Remove obsolete #include <linux/config.h>
[linux-3.10.git] / drivers / ide / ide-tape.c
1 /*
2  * linux/drivers/ide/ide-tape.c         Version 1.19    Nov, 2003
3  *
4  * Copyright (C) 1995 - 1999 Gadi Oxman <gadio@netvision.net.il>
5  *
6  * $Header$
7  *
8  * This driver was constructed as a student project in the software laboratory
9  * of the faculty of electrical engineering in the Technion - Israel's
10  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
11  *
12  * It is hereby placed under the terms of the GNU general public license.
13  * (See linux/COPYING).
14  */
15  
16 /*
17  * IDE ATAPI streaming tape driver.
18  *
19  * This driver is a part of the Linux ide driver and works in co-operation
20  * with linux/drivers/block/ide.c.
21  *
22  * The driver, in co-operation with ide.c, basically traverses the 
23  * request-list for the block device interface. The character device
24  * interface, on the other hand, creates new requests, adds them
25  * to the request-list of the block device, and waits for their completion.
26  *
27  * Pipelined operation mode is now supported on both reads and writes.
28  *
29  * The block device major and minor numbers are determined from the
30  * tape's relative position in the ide interfaces, as explained in ide.c.
31  *
32  * The character device interface consists of the following devices:
33  *
34  * ht0          major 37, minor 0       first  IDE tape, rewind on close.
35  * ht1          major 37, minor 1       second IDE tape, rewind on close.
36  * ...
37  * nht0         major 37, minor 128     first  IDE tape, no rewind on close.
38  * nht1         major 37, minor 129     second IDE tape, no rewind on close.
39  * ...
40  *
41  * Run linux/scripts/MAKEDEV.ide to create the above entries.
42  *
43  * The general magnetic tape commands compatible interface, as defined by
44  * include/linux/mtio.h, is accessible through the character device.
45  *
46  * General ide driver configuration options, such as the interrupt-unmask
47  * flag, can be configured by issuing an ioctl to the block device interface,
48  * as any other ide device.
49  *
50  * Our own ide-tape ioctl's can be issued to either the block device or
51  * the character device interface.
52  *
53  * Maximal throughput with minimal bus load will usually be achieved in the
54  * following scenario:
55  *
56  *      1.      ide-tape is operating in the pipelined operation mode.
57  *      2.      No buffering is performed by the user backup program.
58  *
59  * Testing was done with a 2 GB CONNER CTMA 4000 IDE ATAPI Streaming Tape Drive.
60  * 
61  * Ver 0.1   Nov  1 95   Pre-working code :-)
62  * Ver 0.2   Nov 23 95   A short backup (few megabytes) and restore procedure
63  *                        was successful ! (Using tar cvf ... on the block
64  *                        device interface).
65  *                       A longer backup resulted in major swapping, bad
66  *                        overall Linux performance and eventually failed as
67  *                        we received non serial read-ahead requests from the
68  *                        buffer cache.
69  * Ver 0.3   Nov 28 95   Long backups are now possible, thanks to the
70  *                        character device interface. Linux's responsiveness
71  *                        and performance doesn't seem to be much affected
72  *                        from the background backup procedure.
73  *                       Some general mtio.h magnetic tape operations are
74  *                        now supported by our character device. As a result,
75  *                        popular tape utilities are starting to work with
76  *                        ide tapes :-)
77  *                       The following configurations were tested:
78  *                              1. An IDE ATAPI TAPE shares the same interface
79  *                                 and irq with an IDE ATAPI CDROM.
80  *                              2. An IDE ATAPI TAPE shares the same interface
81  *                                 and irq with a normal IDE disk.
82  *                        Both configurations seemed to work just fine !
83  *                        However, to be on the safe side, it is meanwhile
84  *                        recommended to give the IDE TAPE its own interface
85  *                        and irq.
86  *                       The one thing which needs to be done here is to
87  *                        add a "request postpone" feature to ide.c,
88  *                        so that we won't have to wait for the tape to finish
89  *                        performing a long media access (DSC) request (such
90  *                        as a rewind) before we can access the other device
91  *                        on the same interface. This effect doesn't disturb
92  *                        normal operation most of the time because read/write
93  *                        requests are relatively fast, and once we are
94  *                        performing one tape r/w request, a lot of requests
95  *                        from the other device can be queued and ide.c will
96  *                        service all of them after this single tape request.
97  * Ver 1.0   Dec 11 95   Integrated into Linux 1.3.46 development tree.
98  *                       On each read / write request, we now ask the drive
99  *                        if we can transfer a constant number of bytes
100  *                        (a parameter of the drive) only to its buffers,
101  *                        without causing actual media access. If we can't,
102  *                        we just wait until we can by polling the DSC bit.
103  *                        This ensures that while we are not transferring
104  *                        more bytes than the constant referred to above, the
105  *                        interrupt latency will not become too high and
106  *                        we won't cause an interrupt timeout, as happened
107  *                        occasionally in the previous version.
108  *                       While polling for DSC, the current request is
109  *                        postponed and ide.c is free to handle requests from
110  *                        the other device. This is handled transparently to
111  *                        ide.c. The hwgroup locking method which was used
112  *                        in the previous version was removed.
113  *                       Use of new general features which are provided by
114  *                        ide.c for use with atapi devices.
115  *                        (Programming done by Mark Lord)
116  *                       Few potential bug fixes (Again, suggested by Mark)
117  *                       Single character device data transfers are now
118  *                        not limited in size, as they were before.
119  *                       We are asking the tape about its recommended
120  *                        transfer unit and send a larger data transfer
121  *                        as several transfers of the above size.
122  *                        For best results, use an integral number of this
123  *                        basic unit (which is shown during driver
124  *                        initialization). I will soon add an ioctl to get
125  *                        this important parameter.
126  *                       Our data transfer buffer is allocated on startup,
127  *                        rather than before each data transfer. This should
128  *                        ensure that we will indeed have a data buffer.
129  * Ver 1.1   Dec 14 95   Fixed random problems which occurred when the tape
130  *                        shared an interface with another device.
131  *                        (poll_for_dsc was a complete mess).
132  *                       Removed some old (non-active) code which had
133  *                        to do with supporting buffer cache originated
134  *                        requests.
135  *                       The block device interface can now be opened, so
136  *                        that general ide driver features like the unmask
137  *                        interrupts flag can be selected with an ioctl.
138  *                        This is the only use of the block device interface.
139  *                       New fast pipelined operation mode (currently only on
140  *                        writes). When using the pipelined mode, the
141  *                        throughput can potentially reach the maximum
142  *                        tape supported throughput, regardless of the
143  *                        user backup program. On my tape drive, it sometimes
144  *                        boosted performance by a factor of 2. Pipelined
145  *                        mode is enabled by default, but since it has a few
146  *                        downfalls as well, you may want to disable it.
147  *                        A short explanation of the pipelined operation mode
148  *                        is available below.
149  * Ver 1.2   Jan  1 96   Eliminated pipelined mode race condition.
150  *                       Added pipeline read mode. As a result, restores
151  *                        are now as fast as backups.
152  *                       Optimized shared interface behavior. The new behavior
153  *                        typically results in better IDE bus efficiency and
154  *                        higher tape throughput.
155  *                       Pre-calculation of the expected read/write request
156  *                        service time, based on the tape's parameters. In
157  *                        the pipelined operation mode, this allows us to
158  *                        adjust our polling frequency to a much lower value,
159  *                        and thus to dramatically reduce our load on Linux,
160  *                        without any decrease in performance.
161  *                       Implemented additional mtio.h operations.
162  *                       The recommended user block size is returned by
163  *                        the MTIOCGET ioctl.
164  *                       Additional minor changes.
165  * Ver 1.3   Feb  9 96   Fixed pipelined read mode bug which prevented the
166  *                        use of some block sizes during a restore procedure.
167  *                       The character device interface will now present a
168  *                        continuous view of the media - any mix of block sizes
169  *                        during a backup/restore procedure is supported. The
170  *                        driver will buffer the requests internally and
171  *                        convert them to the tape's recommended transfer
172  *                        unit, making performance almost independent of the
173  *                        chosen user block size.
174  *                       Some improvements in error recovery.
175  *                       By cooperating with ide-dma.c, bus mastering DMA can
176  *                        now sometimes be used with IDE tape drives as well.
177  *                        Bus mastering DMA has the potential to dramatically
178  *                        reduce the CPU's overhead when accessing the device,
179  *                        and can be enabled by using hdparm -d1 on the tape's
180  *                        block device interface. For more info, read the
181  *                        comments in ide-dma.c.
182  * Ver 1.4   Mar 13 96   Fixed serialize support.
183  * Ver 1.5   Apr 12 96   Fixed shared interface operation, broken in 1.3.85.
184  *                       Fixed pipelined read mode inefficiency.
185  *                       Fixed nasty null dereferencing bug.
186  * Ver 1.6   Aug 16 96   Fixed FPU usage in the driver.
187  *                       Fixed end of media bug.
188  * Ver 1.7   Sep 10 96   Minor changes for the CONNER CTT8000-A model.
189  * Ver 1.8   Sep 26 96   Attempt to find a better balance between good
190  *                        interactive response and high system throughput.
191  * Ver 1.9   Nov  5 96   Automatically cross encountered filemarks rather
192  *                        than requiring an explicit FSF command.
193  *                       Abort pending requests at end of media.
194  *                       MTTELL was sometimes returning incorrect results.
195  *                       Return the real block size in the MTIOCGET ioctl.
196  *                       Some error recovery bug fixes.
197  * Ver 1.10  Nov  5 96   Major reorganization.
198  *                       Reduced CPU overhead a bit by eliminating internal
199  *                        bounce buffers.
200  *                       Added module support.
201  *                       Added multiple tape drives support.
202  *                       Added partition support.
203  *                       Rewrote DSC handling.
204  *                       Some portability fixes.
205  *                       Removed ide-tape.h.
206  *                       Additional minor changes.
207  * Ver 1.11  Dec  2 96   Bug fix in previous DSC timeout handling.
208  *                       Use ide_stall_queue() for DSC overlap.
209  *                       Use the maximum speed rather than the current speed
210  *                        to compute the request service time.
211  * Ver 1.12  Dec  7 97   Fix random memory overwriting and/or last block data
212  *                        corruption, which could occur if the total number
213  *                        of bytes written to the tape was not an integral
214  *                        number of tape blocks.
215  *                       Add support for INTERRUPT DRQ devices.
216  * Ver 1.13  Jan  2 98   Add "speed == 0" work-around for HP COLORADO 5GB
217  * Ver 1.14  Dec 30 98   Partial fixes for the Sony/AIWA tape drives.
218  *                       Replace cli()/sti() with hwgroup spinlocks.
219  * Ver 1.15  Mar 25 99   Fix SMP race condition by replacing hwgroup
220  *                        spinlock with private per-tape spinlock.
221  * Ver 1.16  Sep  1 99   Add OnStream tape support.
222  *                       Abort read pipeline on EOD.
223  *                       Wait for the tape to become ready in case it returns
224  *                        "in the process of becoming ready" on open().
225  *                       Fix zero padding of the last written block in
226  *                        case the tape block size is larger than PAGE_SIZE.
227  *                       Decrease the default disconnection time to tn.
228  * Ver 1.16e Oct  3 99   Minor fixes.
229  * Ver 1.16e1 Oct 13 99  Patches by Arnold Niessen,
230  *                          niessen@iae.nl / arnold.niessen@philips.com
231  *                   GO-1)  Undefined code in idetape_read_position
232  *                              according to Gadi's email
233  *                   AJN-1) Minor fix asc == 11 should be asc == 0x11
234  *                               in idetape_issue_packet_command (did effect
235  *                               debugging output only)
236  *                   AJN-2) Added more debugging output, and
237  *                              added ide-tape: where missing. I would also
238  *                              like to add tape->name where possible
239  *                   AJN-3) Added different debug_level's 
240  *                              via /proc/ide/hdc/settings
241  *                              "debug_level" determines amount of debugging output;
242  *                              can be changed using /proc/ide/hdx/settings
243  *                              0 : almost no debugging output
244  *                              1 : 0+output errors only
245  *                              2 : 1+output all sensekey/asc
246  *                              3 : 2+follow all chrdev related procedures
247  *                              4 : 3+follow all procedures
248  *                              5 : 4+include pc_stack rq_stack info
249  *                              6 : 5+USE_COUNT updates
250  *                   AJN-4) Fixed timeout for retension in idetape_queue_pc_tail
251  *                              from 5 to 10 minutes
252  *                   AJN-5) Changed maximum number of blocks to skip when
253  *                              reading tapes with multiple consecutive write
254  *                              errors from 100 to 1000 in idetape_get_logical_blk
255  *                   Proposed changes to code:
256  *                   1) output "logical_blk_num" via /proc
257  *                   2) output "current_operation" via /proc
258  *                   3) Either solve or document the fact that `mt rewind' is
259  *                      required after reading from /dev/nhtx to be
260  *                      able to rmmod the idetape module;
261  *                      Also, sometimes an application finishes but the
262  *                      device remains `busy' for some time. Same cause ?
263  *                   Proposed changes to release-notes:
264  *                   4) write a simple `quickstart' section in the
265  *                      release notes; I volunteer if you don't want to
266  *                   5) include a pointer to video4linux in the doc
267  *                      to stimulate video applications
268  *                   6) release notes lines 331 and 362: explain what happens
269  *                      if the application data rate is higher than 1100 KB/s; 
270  *                      similar approach to lower-than-500 kB/s ?
271  *                   7) 6.6 Comparison; wouldn't it be better to allow different 
272  *                      strategies for read and write ?
273  *                      Wouldn't it be better to control the tape buffer
274  *                      contents instead of the bandwidth ?
275  *                   8) line 536: replace will by would (if I understand
276  *                      this section correctly, a hypothetical and unwanted situation
277  *                       is being described)
278  * Ver 1.16f Dec 15 99   Change place of the secondary OnStream header frames.
279  * Ver 1.17  Nov 2000 / Jan 2001  Marcel Mol, marcel@mesa.nl
280  *                      - Add idetape_onstream_mode_sense_tape_parameter_page
281  *                        function to get tape capacity in frames: tape->capacity.
282  *                      - Add support for DI-50 drives( or any DI- drive).
283  *                      - 'workaround' for read error/blank block around block 3000.
284  *                      - Implement Early warning for end of media for Onstream.
285  *                      - Cosmetic code changes for readability.
286  *                      - Idetape_position_tape should not use SKIP bit during
287  *                        Onstream read recovery.
288  *                      - Add capacity, logical_blk_num and first/last_frame_position
289  *                        to /proc/ide/hd?/settings.
290  *                      - Module use count was gone in the Linux 2.4 driver.
291  * Ver 1.17a Apr 2001 Willem Riede osst@riede.org
292  *                      - Get drive's actual block size from mode sense block descriptor
293  *                      - Limit size of pipeline
294  * Ver 1.17b Oct 2002   Alan Stern <stern@rowland.harvard.edu>
295  *                      Changed IDETAPE_MIN_PIPELINE_STAGES to 1 and actually used
296  *                       it in the code!
297  *                      Actually removed aborted stages in idetape_abort_pipeline
298  *                       instead of just changing the command code.
299  *                      Made the transfer byte count for Request Sense equal to the
300  *                       actual length of the data transfer.
301  *                      Changed handling of partial data transfers: they do not
302  *                       cause DMA errors.
303  *                      Moved initiation of DMA transfers to the correct place.
304  *                      Removed reference to unallocated memory.
305  *                      Made __idetape_discard_read_pipeline return the number of
306  *                       sectors skipped, not the number of stages.
307  *                      Replaced errant kfree() calls with __idetape_kfree_stage().
308  *                      Fixed off-by-one error in testing the pipeline length.
309  *                      Fixed handling of filemarks in the read pipeline.
310  *                      Small code optimization for MTBSF and MTBSFM ioctls.
311  *                      Don't try to unlock the door during device close if is
312  *                       already unlocked!
313  *                      Cosmetic fixes to miscellaneous debugging output messages.
314  *                      Set the minimum /proc/ide/hd?/settings values for "pipeline",
315  *                       "pipeline_min", and "pipeline_max" to 1.
316  *
317  * Here are some words from the first releases of hd.c, which are quoted
318  * in ide.c and apply here as well:
319  *
320  * | Special care is recommended.  Have Fun!
321  *
322  */
323
324 /*
325  * An overview of the pipelined operation mode.
326  *
327  * In the pipelined write mode, we will usually just add requests to our
328  * pipeline and return immediately, before we even start to service them. The
329  * user program will then have enough time to prepare the next request while
330  * we are still busy servicing previous requests. In the pipelined read mode,
331  * the situation is similar - we add read-ahead requests into the pipeline,
332  * before the user even requested them.
333  *
334  * The pipeline can be viewed as a "safety net" which will be activated when
335  * the system load is high and prevents the user backup program from keeping up
336  * with the current tape speed. At this point, the pipeline will get
337  * shorter and shorter but the tape will still be streaming at the same speed.
338  * Assuming we have enough pipeline stages, the system load will hopefully
339  * decrease before the pipeline is completely empty, and the backup program
340  * will be able to "catch up" and refill the pipeline again.
341  * 
342  * When using the pipelined mode, it would be best to disable any type of
343  * buffering done by the user program, as ide-tape already provides all the
344  * benefits in the kernel, where it can be done in a more efficient way.
345  * As we will usually not block the user program on a request, the most
346  * efficient user code will then be a simple read-write-read-... cycle.
347  * Any additional logic will usually just slow down the backup process.
348  *
349  * Using the pipelined mode, I get a constant over 400 KBps throughput,
350  * which seems to be the maximum throughput supported by my tape.
351  *
352  * However, there are some downfalls:
353  *
354  *      1.      We use memory (for data buffers) in proportional to the number
355  *              of pipeline stages (each stage is about 26 KB with my tape).
356  *      2.      In the pipelined write mode, we cheat and postpone error codes
357  *              to the user task. In read mode, the actual tape position
358  *              will be a bit further than the last requested block.
359  *
360  * Concerning (1):
361  *
362  *      1.      We allocate stages dynamically only when we need them. When
363  *              we don't need them, we don't consume additional memory. In
364  *              case we can't allocate stages, we just manage without them
365  *              (at the expense of decreased throughput) so when Linux is
366  *              tight in memory, we will not pose additional difficulties.
367  *
368  *      2.      The maximum number of stages (which is, in fact, the maximum
369  *              amount of memory) which we allocate is limited by the compile
370  *              time parameter IDETAPE_MAX_PIPELINE_STAGES.
371  *
372  *      3.      The maximum number of stages is a controlled parameter - We
373  *              don't start from the user defined maximum number of stages
374  *              but from the lower IDETAPE_MIN_PIPELINE_STAGES (again, we
375  *              will not even allocate this amount of stages if the user
376  *              program can't handle the speed). We then implement a feedback
377  *              loop which checks if the pipeline is empty, and if it is, we
378  *              increase the maximum number of stages as necessary until we
379  *              reach the optimum value which just manages to keep the tape
380  *              busy with minimum allocated memory or until we reach
381  *              IDETAPE_MAX_PIPELINE_STAGES.
382  *
383  * Concerning (2):
384  *
385  *      In pipelined write mode, ide-tape can not return accurate error codes
386  *      to the user program since we usually just add the request to the
387  *      pipeline without waiting for it to be serviced. In case an error
388  *      occurs, I will report it on the next user request.
389  *
390  *      In the pipelined read mode, subsequent read requests or forward
391  *      filemark spacing will perform correctly, as we preserve all blocks
392  *      and filemarks which we encountered during our excess read-ahead.
393  * 
394  *      For accurate tape positioning and error reporting, disabling
395  *      pipelined mode might be the best option.
396  *
397  * You can enable/disable/tune the pipelined operation mode by adjusting
398  * the compile time parameters below.
399  */
400
401 /*
402  *      Possible improvements.
403  *
404  *      1.      Support for the ATAPI overlap protocol.
405  *
406  *              In order to maximize bus throughput, we currently use the DSC
407  *              overlap method which enables ide.c to service requests from the
408  *              other device while the tape is busy executing a command. The
409  *              DSC overlap method involves polling the tape's status register
410  *              for the DSC bit, and servicing the other device while the tape
411  *              isn't ready.
412  *
413  *              In the current QIC development standard (December 1995),
414  *              it is recommended that new tape drives will *in addition* 
415  *              implement the ATAPI overlap protocol, which is used for the
416  *              same purpose - efficient use of the IDE bus, but is interrupt
417  *              driven and thus has much less CPU overhead.
418  *
419  *              ATAPI overlap is likely to be supported in most new ATAPI
420  *              devices, including new ATAPI cdroms, and thus provides us
421  *              a method by which we can achieve higher throughput when
422  *              sharing a (fast) ATA-2 disk with any (slow) new ATAPI device.
423  */
424
425 #define IDETAPE_VERSION "1.19"
426
427 #include <linux/module.h>
428 #include <linux/types.h>
429 #include <linux/string.h>
430 #include <linux/kernel.h>
431 #include <linux/delay.h>
432 #include <linux/timer.h>
433 #include <linux/mm.h>
434 #include <linux/interrupt.h>
435 #include <linux/jiffies.h>
436 #include <linux/major.h>
437 #include <linux/errno.h>
438 #include <linux/genhd.h>
439 #include <linux/slab.h>
440 #include <linux/pci.h>
441 #include <linux/ide.h>
442 #include <linux/smp_lock.h>
443 #include <linux/completion.h>
444 #include <linux/bitops.h>
445 #include <linux/mutex.h>
446
447 #include <asm/byteorder.h>
448 #include <asm/irq.h>
449 #include <asm/uaccess.h>
450 #include <asm/io.h>
451 #include <asm/unaligned.h>
452
453 /*
454  * partition
455  */
456 typedef struct os_partition_s {
457         __u8    partition_num;
458         __u8    par_desc_ver;
459         __u16   wrt_pass_cntr;
460         __u32   first_frame_addr;
461         __u32   last_frame_addr;
462         __u32   eod_frame_addr;
463 } os_partition_t;
464
465 /*
466  * DAT entry
467  */
468 typedef struct os_dat_entry_s {
469         __u32   blk_sz;
470         __u16   blk_cnt;
471         __u8    flags;
472         __u8    reserved;
473 } os_dat_entry_t;
474
475 /*
476  * DAT
477  */
478 #define OS_DAT_FLAGS_DATA       (0xc)
479 #define OS_DAT_FLAGS_MARK       (0x1)
480
481 typedef struct os_dat_s {
482         __u8            dat_sz;
483         __u8            reserved1;
484         __u8            entry_cnt;
485         __u8            reserved3;
486         os_dat_entry_t  dat_list[16];
487 } os_dat_t;
488
489 #include <linux/mtio.h>
490
491 /**************************** Tunable parameters *****************************/
492
493
494 /*
495  *      Pipelined mode parameters.
496  *
497  *      We try to use the minimum number of stages which is enough to
498  *      keep the tape constantly streaming. To accomplish that, we implement
499  *      a feedback loop around the maximum number of stages:
500  *
501  *      We start from MIN maximum stages (we will not even use MIN stages
502  *      if we don't need them), increment it by RATE*(MAX-MIN)
503  *      whenever we sense that the pipeline is empty, until we reach
504  *      the optimum value or until we reach MAX.
505  *
506  *      Setting the following parameter to 0 is illegal: the pipelined mode
507  *      cannot be disabled (calculate_speeds() divides by tape->max_stages.)
508  */
509 #define IDETAPE_MIN_PIPELINE_STAGES       1
510 #define IDETAPE_MAX_PIPELINE_STAGES     400
511 #define IDETAPE_INCREASE_STAGES_RATE     20
512
513 /*
514  *      The following are used to debug the driver:
515  *
516  *      Setting IDETAPE_DEBUG_INFO to 1 will report device capabilities.
517  *      Setting IDETAPE_DEBUG_LOG to 1 will log driver flow control.
518  *      Setting IDETAPE_DEBUG_BUGS to 1 will enable self-sanity checks in
519  *      some places.
520  *
521  *      Setting them to 0 will restore normal operation mode:
522  *
523  *              1.      Disable logging normal successful operations.
524  *              2.      Disable self-sanity checks.
525  *              3.      Errors will still be logged, of course.
526  *
527  *      All the #if DEBUG code will be removed some day, when the driver
528  *      is verified to be stable enough. This will make it much more
529  *      esthetic.
530  */
531 #define IDETAPE_DEBUG_INFO              0
532 #define IDETAPE_DEBUG_LOG               0
533 #define IDETAPE_DEBUG_BUGS              1
534
535 /*
536  *      After each failed packet command we issue a request sense command
537  *      and retry the packet command IDETAPE_MAX_PC_RETRIES times.
538  *
539  *      Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
540  */
541 #define IDETAPE_MAX_PC_RETRIES          3
542
543 /*
544  *      With each packet command, we allocate a buffer of
545  *      IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet
546  *      commands (Not for READ/WRITE commands).
547  */
548 #define IDETAPE_PC_BUFFER_SIZE          256
549
550 /*
551  *      In various places in the driver, we need to allocate storage
552  *      for packet commands and requests, which will remain valid while
553  *      we leave the driver to wait for an interrupt or a timeout event.
554  */
555 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
556
557 /*
558  * Some drives (for example, Seagate STT3401A Travan) require a very long
559  * timeout, because they don't return an interrupt or clear their busy bit
560  * until after the command completes (even retension commands).
561  */
562 #define IDETAPE_WAIT_CMD                (900*HZ)
563
564 /*
565  *      The following parameter is used to select the point in the internal
566  *      tape fifo in which we will start to refill the buffer. Decreasing
567  *      the following parameter will improve the system's latency and
568  *      interactive response, while using a high value might improve sytem
569  *      throughput.
570  */
571 #define IDETAPE_FIFO_THRESHOLD          2
572
573 /*
574  *      DSC polling parameters.
575  *
576  *      Polling for DSC (a single bit in the status register) is a very
577  *      important function in ide-tape. There are two cases in which we
578  *      poll for DSC:
579  *
580  *      1.      Before a read/write packet command, to ensure that we
581  *              can transfer data from/to the tape's data buffers, without
582  *              causing an actual media access. In case the tape is not
583  *              ready yet, we take out our request from the device
584  *              request queue, so that ide.c will service requests from
585  *              the other device on the same interface meanwhile.
586  *
587  *      2.      After the successful initialization of a "media access
588  *              packet command", which is a command which can take a long
589  *              time to complete (it can be several seconds or even an hour).
590  *
591  *              Again, we postpone our request in the middle to free the bus
592  *              for the other device. The polling frequency here should be
593  *              lower than the read/write frequency since those media access
594  *              commands are slow. We start from a "fast" frequency -
595  *              IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
596  *              after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
597  *              lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
598  *
599  *      We also set a timeout for the timer, in case something goes wrong.
600  *      The timeout should be longer then the maximum execution time of a
601  *      tape operation.
602  */
603  
604 /*
605  *      DSC timings.
606  */
607 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
608 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
609 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
610 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
611 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
612 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
613 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
614
615 /*************************** End of tunable parameters ***********************/
616
617 /*
618  *      Debugging/Performance analysis
619  *
620  *      I/O trace support
621  */
622 #define USE_IOTRACE     0
623 #if USE_IOTRACE
624 #include <linux/io_trace.h>
625 #define IO_IDETAPE_FIFO 500
626 #endif
627
628 /*
629  *      Read/Write error simulation
630  */
631 #define SIMULATE_ERRORS                 0
632
633 /*
634  *      For general magnetic tape device compatibility.
635  */
636 typedef enum {
637         idetape_direction_none,
638         idetape_direction_read,
639         idetape_direction_write
640 } idetape_chrdev_direction_t;
641
642 struct idetape_bh {
643         unsigned short b_size;
644         atomic_t b_count;
645         struct idetape_bh *b_reqnext;
646         char *b_data;
647 };
648
649 /*
650  *      Our view of a packet command.
651  */
652 typedef struct idetape_packet_command_s {
653         u8 c[12];                               /* Actual packet bytes */
654         int retries;                            /* On each retry, we increment retries */
655         int error;                              /* Error code */
656         int request_transfer;                   /* Bytes to transfer */
657         int actually_transferred;               /* Bytes actually transferred */
658         int buffer_size;                        /* Size of our data buffer */
659         struct idetape_bh *bh;
660         char *b_data;
661         int b_count;
662         u8 *buffer;                             /* Data buffer */
663         u8 *current_position;                   /* Pointer into the above buffer */
664         ide_startstop_t (*callback) (ide_drive_t *);    /* Called when this packet command is completed */
665         u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];   /* Temporary buffer */
666         unsigned long flags;                    /* Status/Action bit flags: long for set_bit */
667 } idetape_pc_t;
668
669 /*
670  *      Packet command flag bits.
671  */
672 /* Set when an error is considered normal - We won't retry */
673 #define PC_ABORT                        0
674 /* 1 When polling for DSC on a media access command */
675 #define PC_WAIT_FOR_DSC                 1
676 /* 1 when we prefer to use DMA if possible */
677 #define PC_DMA_RECOMMENDED              2
678 /* 1 while DMA in progress */
679 #define PC_DMA_IN_PROGRESS              3
680 /* 1 when encountered problem during DMA */
681 #define PC_DMA_ERROR                    4
682 /* Data direction */
683 #define PC_WRITING                      5
684
685 /*
686  *      Capabilities and Mechanical Status Page
687  */
688 typedef struct {
689         unsigned        page_code       :6;     /* Page code - Should be 0x2a */
690         __u8            reserved0_6     :1;
691         __u8            ps              :1;     /* parameters saveable */
692         __u8            page_length;            /* Page Length - Should be 0x12 */
693         __u8            reserved2, reserved3;
694         unsigned        ro              :1;     /* Read Only Mode */
695         unsigned        reserved4_1234  :4;
696         unsigned        sprev           :1;     /* Supports SPACE in the reverse direction */
697         unsigned        reserved4_67    :2;
698         unsigned        reserved5_012   :3;
699         unsigned        efmt            :1;     /* Supports ERASE command initiated formatting */
700         unsigned        reserved5_4     :1;
701         unsigned        qfa             :1;     /* Supports the QFA two partition formats */
702         unsigned        reserved5_67    :2;
703         unsigned        lock            :1;     /* Supports locking the volume */
704         unsigned        locked          :1;     /* The volume is locked */
705         unsigned        prevent         :1;     /* The device defaults in the prevent state after power up */   
706         unsigned        eject           :1;     /* The device can eject the volume */
707         __u8            disconnect      :1;     /* The device can break request > ctl */        
708         __u8            reserved6_5     :1;
709         unsigned        ecc             :1;     /* Supports error correction */
710         unsigned        cmprs           :1;     /* Supports data compression */
711         unsigned        reserved7_0     :1;
712         unsigned        blk512          :1;     /* Supports 512 bytes block size */
713         unsigned        blk1024         :1;     /* Supports 1024 bytes block size */
714         unsigned        reserved7_3_6   :4;
715         unsigned        blk32768        :1;     /* slowb - the device restricts the byte count for PIO */
716                                                 /* transfers for slow buffer memory ??? */
717                                                 /* Also 32768 block size in some cases */
718         __u16           max_speed;              /* Maximum speed supported in KBps */
719         __u8            reserved10, reserved11;
720         __u16           ctl;                    /* Continuous Transfer Limit in blocks */
721         __u16           speed;                  /* Current Speed, in KBps */
722         __u16           buffer_size;            /* Buffer Size, in 512 bytes */
723         __u8            reserved18, reserved19;
724 } idetape_capabilities_page_t;
725
726 /*
727  *      Block Size Page
728  */
729 typedef struct {
730         unsigned        page_code       :6;     /* Page code - Should be 0x30 */
731         unsigned        reserved1_6     :1;
732         unsigned        ps              :1;
733         __u8            page_length;            /* Page Length - Should be 2 */
734         __u8            reserved2;
735         unsigned        play32          :1;
736         unsigned        play32_5        :1;
737         unsigned        reserved2_23    :2;
738         unsigned        record32        :1;
739         unsigned        record32_5      :1;
740         unsigned        reserved2_6     :1;
741         unsigned        one             :1;
742 } idetape_block_size_page_t;
743
744 /*
745  *      A pipeline stage.
746  */
747 typedef struct idetape_stage_s {
748         struct request rq;                      /* The corresponding request */
749         struct idetape_bh *bh;                  /* The data buffers */
750         struct idetape_stage_s *next;           /* Pointer to the next stage */
751 } idetape_stage_t;
752
753 /*
754  *      REQUEST SENSE packet command result - Data Format.
755  */
756 typedef struct {
757         unsigned        error_code      :7;     /* Current of deferred errors */
758         unsigned        valid           :1;     /* The information field conforms to QIC-157C */
759         __u8            reserved1       :8;     /* Segment Number - Reserved */
760         unsigned        sense_key       :4;     /* Sense Key */
761         unsigned        reserved2_4     :1;     /* Reserved */
762         unsigned        ili             :1;     /* Incorrect Length Indicator */
763         unsigned        eom             :1;     /* End Of Medium */
764         unsigned        filemark        :1;     /* Filemark */
765         __u32           information __attribute__ ((packed));
766         __u8            asl;                    /* Additional sense length (n-7) */
767         __u32           command_specific;       /* Additional command specific information */
768         __u8            asc;                    /* Additional Sense Code */
769         __u8            ascq;                   /* Additional Sense Code Qualifier */
770         __u8            replaceable_unit_code;  /* Field Replaceable Unit Code */
771         unsigned        sk_specific1    :7;     /* Sense Key Specific */
772         unsigned        sksv            :1;     /* Sense Key Specific information is valid */
773         __u8            sk_specific2;           /* Sense Key Specific */
774         __u8            sk_specific3;           /* Sense Key Specific */
775         __u8            pad[2];                 /* Padding to 20 bytes */
776 } idetape_request_sense_result_t;
777
778
779 /*
780  *      Most of our global data which we need to save even as we leave the
781  *      driver due to an interrupt or a timer event is stored in a variable
782  *      of type idetape_tape_t, defined below.
783  */
784 typedef struct ide_tape_obj {
785         ide_drive_t     *drive;
786         ide_driver_t    *driver;
787         struct gendisk  *disk;
788         struct kref     kref;
789
790         /*
791          *      Since a typical character device operation requires more
792          *      than one packet command, we provide here enough memory
793          *      for the maximum of interconnected packet commands.
794          *      The packet commands are stored in the circular array pc_stack.
795          *      pc_stack_index points to the last used entry, and warps around
796          *      to the start when we get to the last array entry.
797          *
798          *      pc points to the current processed packet command.
799          *
800          *      failed_pc points to the last failed packet command, or contains
801          *      NULL if we do not need to retry any packet command. This is
802          *      required since an additional packet command is needed before the
803          *      retry, to get detailed information on what went wrong.
804          */
805         /* Current packet command */
806         idetape_pc_t *pc;
807         /* Last failed packet command */
808         idetape_pc_t *failed_pc;
809         /* Packet command stack */
810         idetape_pc_t pc_stack[IDETAPE_PC_STACK];
811         /* Next free packet command storage space */
812         int pc_stack_index;
813         struct request rq_stack[IDETAPE_PC_STACK];
814         /* We implement a circular array */
815         int rq_stack_index;
816
817         /*
818          *      DSC polling variables.
819          *
820          *      While polling for DSC we use postponed_rq to postpone the
821          *      current request so that ide.c will be able to service
822          *      pending requests on the other device. Note that at most
823          *      we will have only one DSC (usually data transfer) request
824          *      in the device request queue. Additional requests can be
825          *      queued in our internal pipeline, but they will be visible
826          *      to ide.c only one at a time.
827          */
828         struct request *postponed_rq;
829         /* The time in which we started polling for DSC */
830         unsigned long dsc_polling_start;
831         /* Timer used to poll for dsc */
832         struct timer_list dsc_timer;
833         /* Read/Write dsc polling frequency */
834         unsigned long best_dsc_rw_frequency;
835         /* The current polling frequency */
836         unsigned long dsc_polling_frequency;
837         /* Maximum waiting time */
838         unsigned long dsc_timeout;
839
840         /*
841          *      Read position information
842          */
843         u8 partition;
844         /* Current block */
845         unsigned int first_frame_position;
846         unsigned int last_frame_position;
847         unsigned int blocks_in_buffer;
848
849         /*
850          *      Last error information
851          */
852         u8 sense_key, asc, ascq;
853
854         /*
855          *      Character device operation
856          */
857         unsigned int minor;
858         /* device name */
859         char name[4];
860         /* Current character device data transfer direction */
861         idetape_chrdev_direction_t chrdev_direction;
862
863         /*
864          *      Device information
865          */
866         /* Usually 512 or 1024 bytes */
867         unsigned short tape_block_size;
868         int user_bs_factor;
869         /* Copy of the tape's Capabilities and Mechanical Page */
870         idetape_capabilities_page_t capabilities;
871
872         /*
873          *      Active data transfer request parameters.
874          *
875          *      At most, there is only one ide-tape originated data transfer
876          *      request in the device request queue. This allows ide.c to
877          *      easily service requests from the other device when we
878          *      postpone our active request. In the pipelined operation
879          *      mode, we use our internal pipeline structure to hold
880          *      more data requests.
881          *
882          *      The data buffer size is chosen based on the tape's
883          *      recommendation.
884          */
885         /* Pointer to the request which is waiting in the device request queue */
886         struct request *active_data_request;
887         /* Data buffer size (chosen based on the tape's recommendation */
888         int stage_size;
889         idetape_stage_t *merge_stage;
890         int merge_stage_size;
891         struct idetape_bh *bh;
892         char *b_data;
893         int b_count;
894         
895         /*
896          *      Pipeline parameters.
897          *
898          *      To accomplish non-pipelined mode, we simply set the following
899          *      variables to zero (or NULL, where appropriate).
900          */
901         /* Number of currently used stages */
902         int nr_stages;
903         /* Number of pending stages */
904         int nr_pending_stages;
905         /* We will not allocate more than this number of stages */
906         int max_stages, min_pipeline, max_pipeline;
907         /* The first stage which will be removed from the pipeline */
908         idetape_stage_t *first_stage;
909         /* The currently active stage */
910         idetape_stage_t *active_stage;
911         /* Will be serviced after the currently active request */
912         idetape_stage_t *next_stage;
913         /* New requests will be added to the pipeline here */
914         idetape_stage_t *last_stage;
915         /* Optional free stage which we can use */
916         idetape_stage_t *cache_stage;
917         int pages_per_stage;
918         /* Wasted space in each stage */
919         int excess_bh_size;
920
921         /* Status/Action flags: long for set_bit */
922         unsigned long flags;
923         /* protects the ide-tape queue */
924         spinlock_t spinlock;
925
926         /*
927          * Measures average tape speed
928          */
929         unsigned long avg_time;
930         int avg_size;
931         int avg_speed;
932
933         /* last sense information */
934         idetape_request_sense_result_t sense;
935
936         char vendor_id[10];
937         char product_id[18];
938         char firmware_revision[6];
939         int firmware_revision_num;
940
941         /* the door is currently locked */
942         int door_locked;
943         /* the tape hardware is write protected */
944         char drv_write_prot;
945         /* the tape is write protected (hardware or opened as read-only) */
946         char write_prot;
947
948         /*
949          * Limit the number of times a request can
950          * be postponed, to avoid an infinite postpone
951          * deadlock.
952          */
953         /* request postpone count limit */
954         int postpone_cnt;
955
956         /*
957          * Measures number of frames:
958          *
959          * 1. written/read to/from the driver pipeline (pipeline_head).
960          * 2. written/read to/from the tape buffers (idetape_bh).
961          * 3. written/read by the tape to/from the media (tape_head).
962          */
963         int pipeline_head;
964         int buffer_head;
965         int tape_head;
966         int last_tape_head;
967
968         /*
969          * Speed control at the tape buffers input/output
970          */
971         unsigned long insert_time;
972         int insert_size;
973         int insert_speed;
974         int max_insert_speed;
975         int measure_insert_time;
976
977         /*
978          * Measure tape still time, in milliseconds
979          */
980         unsigned long tape_still_time_begin;
981         int tape_still_time;
982
983         /*
984          * Speed regulation negative feedback loop
985          */
986         int speed_control;
987         int pipeline_head_speed;
988         int controlled_pipeline_head_speed;
989         int uncontrolled_pipeline_head_speed;
990         int controlled_last_pipeline_head;
991         int uncontrolled_last_pipeline_head;
992         unsigned long uncontrolled_pipeline_head_time;
993         unsigned long controlled_pipeline_head_time;
994         int controlled_previous_pipeline_head;
995         int uncontrolled_previous_pipeline_head;
996         unsigned long controlled_previous_head_time;
997         unsigned long uncontrolled_previous_head_time;
998         int restart_speed_control_req;
999
1000         /*
1001          * Debug_level determines amount of debugging output;
1002          * can be changed using /proc/ide/hdx/settings
1003          * 0 : almost no debugging output
1004          * 1 : 0+output errors only
1005          * 2 : 1+output all sensekey/asc
1006          * 3 : 2+follow all chrdev related procedures
1007          * 4 : 3+follow all procedures
1008          * 5 : 4+include pc_stack rq_stack info
1009          * 6 : 5+USE_COUNT updates
1010          */
1011          int debug_level; 
1012 } idetape_tape_t;
1013
1014 static DEFINE_MUTEX(idetape_ref_mutex);
1015
1016 static struct class *idetape_sysfs_class;
1017
1018 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
1019
1020 #define ide_tape_g(disk) \
1021         container_of((disk)->private_data, struct ide_tape_obj, driver)
1022
1023 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
1024 {
1025         struct ide_tape_obj *tape = NULL;
1026
1027         mutex_lock(&idetape_ref_mutex);
1028         tape = ide_tape_g(disk);
1029         if (tape)
1030                 kref_get(&tape->kref);
1031         mutex_unlock(&idetape_ref_mutex);
1032         return tape;
1033 }
1034
1035 static void ide_tape_release(struct kref *);
1036
1037 static void ide_tape_put(struct ide_tape_obj *tape)
1038 {
1039         mutex_lock(&idetape_ref_mutex);
1040         kref_put(&tape->kref, ide_tape_release);
1041         mutex_unlock(&idetape_ref_mutex);
1042 }
1043
1044 /*
1045  *      Tape door status
1046  */
1047 #define DOOR_UNLOCKED                   0
1048 #define DOOR_LOCKED                     1
1049 #define DOOR_EXPLICITLY_LOCKED          2
1050
1051 /*
1052  *      Tape flag bits values.
1053  */
1054 #define IDETAPE_IGNORE_DSC              0
1055 #define IDETAPE_ADDRESS_VALID           1       /* 0 When the tape position is unknown */
1056 #define IDETAPE_BUSY                    2       /* Device already opened */
1057 #define IDETAPE_PIPELINE_ERROR          3       /* Error detected in a pipeline stage */
1058 #define IDETAPE_DETECT_BS               4       /* Attempt to auto-detect the current user block size */
1059 #define IDETAPE_FILEMARK                5       /* Currently on a filemark */
1060 #define IDETAPE_DRQ_INTERRUPT           6       /* DRQ interrupt device */
1061 #define IDETAPE_READ_ERROR              7
1062 #define IDETAPE_PIPELINE_ACTIVE         8       /* pipeline active */
1063 /* 0 = no tape is loaded, so we don't rewind after ejecting */
1064 #define IDETAPE_MEDIUM_PRESENT          9
1065
1066 /*
1067  *      Supported ATAPI tape drives packet commands
1068  */
1069 #define IDETAPE_TEST_UNIT_READY_CMD     0x00
1070 #define IDETAPE_REWIND_CMD              0x01
1071 #define IDETAPE_REQUEST_SENSE_CMD       0x03
1072 #define IDETAPE_READ_CMD                0x08
1073 #define IDETAPE_WRITE_CMD               0x0a
1074 #define IDETAPE_WRITE_FILEMARK_CMD      0x10
1075 #define IDETAPE_SPACE_CMD               0x11
1076 #define IDETAPE_INQUIRY_CMD             0x12
1077 #define IDETAPE_ERASE_CMD               0x19
1078 #define IDETAPE_MODE_SENSE_CMD          0x1a
1079 #define IDETAPE_MODE_SELECT_CMD         0x15
1080 #define IDETAPE_LOAD_UNLOAD_CMD         0x1b
1081 #define IDETAPE_PREVENT_CMD             0x1e
1082 #define IDETAPE_LOCATE_CMD              0x2b
1083 #define IDETAPE_READ_POSITION_CMD       0x34
1084 #define IDETAPE_READ_BUFFER_CMD         0x3c
1085 #define IDETAPE_SET_SPEED_CMD           0xbb
1086
1087 /*
1088  *      Some defines for the READ BUFFER command
1089  */
1090 #define IDETAPE_RETRIEVE_FAULTY_BLOCK   6
1091
1092 /*
1093  *      Some defines for the SPACE command
1094  */
1095 #define IDETAPE_SPACE_OVER_FILEMARK     1
1096 #define IDETAPE_SPACE_TO_EOD            3
1097
1098 /*
1099  *      Some defines for the LOAD UNLOAD command
1100  */
1101 #define IDETAPE_LU_LOAD_MASK            1
1102 #define IDETAPE_LU_RETENSION_MASK       2
1103 #define IDETAPE_LU_EOT_MASK             4
1104
1105 /*
1106  *      Special requests for our block device strategy routine.
1107  *
1108  *      In order to service a character device command, we add special
1109  *      requests to the tail of our block device request queue and wait
1110  *      for their completion.
1111  */
1112
1113 enum {
1114         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
1115         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
1116         REQ_IDETAPE_READ        = (1 << 2),
1117         REQ_IDETAPE_WRITE       = (1 << 3),
1118         REQ_IDETAPE_READ_BUFFER = (1 << 4),
1119 };
1120
1121 /*
1122  *      Error codes which are returned in rq->errors to the higher part
1123  *      of the driver.
1124  */
1125 #define IDETAPE_ERROR_GENERAL           101
1126 #define IDETAPE_ERROR_FILEMARK          102
1127 #define IDETAPE_ERROR_EOD               103
1128
1129 /*
1130  *      The following is used to format the general configuration word of
1131  *      the ATAPI IDENTIFY DEVICE command.
1132  */
1133 struct idetape_id_gcw { 
1134         unsigned packet_size            :2;     /* Packet Size */
1135         unsigned reserved234            :3;     /* Reserved */
1136         unsigned drq_type               :2;     /* Command packet DRQ type */
1137         unsigned removable              :1;     /* Removable media */
1138         unsigned device_type            :5;     /* Device type */
1139         unsigned reserved13             :1;     /* Reserved */
1140         unsigned protocol               :2;     /* Protocol type */
1141 };
1142
1143 /*
1144  *      INQUIRY packet command - Data Format (From Table 6-8 of QIC-157C)
1145  */
1146 typedef struct {
1147         unsigned        device_type     :5;     /* Peripheral Device Type */
1148         unsigned        reserved0_765   :3;     /* Peripheral Qualifier - Reserved */
1149         unsigned        reserved1_6t0   :7;     /* Reserved */
1150         unsigned        rmb             :1;     /* Removable Medium Bit */
1151         unsigned        ansi_version    :3;     /* ANSI Version */
1152         unsigned        ecma_version    :3;     /* ECMA Version */
1153         unsigned        iso_version     :2;     /* ISO Version */
1154         unsigned        response_format :4;     /* Response Data Format */
1155         unsigned        reserved3_45    :2;     /* Reserved */
1156         unsigned        reserved3_6     :1;     /* TrmIOP - Reserved */
1157         unsigned        reserved3_7     :1;     /* AENC - Reserved */
1158         __u8            additional_length;      /* Additional Length (total_length-4) */
1159         __u8            rsv5, rsv6, rsv7;       /* Reserved */
1160         __u8            vendor_id[8];           /* Vendor Identification */
1161         __u8            product_id[16];         /* Product Identification */
1162         __u8            revision_level[4];      /* Revision Level */
1163         __u8            vendor_specific[20];    /* Vendor Specific - Optional */
1164         __u8            reserved56t95[40];      /* Reserved - Optional */
1165                                                 /* Additional information may be returned */
1166 } idetape_inquiry_result_t;
1167
1168 /*
1169  *      READ POSITION packet command - Data Format (From Table 6-57)
1170  */
1171 typedef struct {
1172         unsigned        reserved0_10    :2;     /* Reserved */
1173         unsigned        bpu             :1;     /* Block Position Unknown */    
1174         unsigned        reserved0_543   :3;     /* Reserved */
1175         unsigned        eop             :1;     /* End Of Partition */
1176         unsigned        bop             :1;     /* Beginning Of Partition */
1177         u8              partition;              /* Partition Number */
1178         u8              reserved2, reserved3;   /* Reserved */
1179         u32             first_block;            /* First Block Location */
1180         u32             last_block;             /* Last Block Location (Optional) */
1181         u8              reserved12;             /* Reserved */
1182         u8              blocks_in_buffer[3];    /* Blocks In Buffer - (Optional) */
1183         u32             bytes_in_buffer;        /* Bytes In Buffer (Optional) */
1184 } idetape_read_position_result_t;
1185
1186 /*
1187  *      Follows structures which are related to the SELECT SENSE / MODE SENSE
1188  *      packet commands. Those packet commands are still not supported
1189  *      by ide-tape.
1190  */
1191 #define IDETAPE_BLOCK_DESCRIPTOR        0
1192 #define IDETAPE_CAPABILITIES_PAGE       0x2a
1193 #define IDETAPE_PARAMTR_PAGE            0x2b   /* Onstream DI-x0 only */
1194 #define IDETAPE_BLOCK_SIZE_PAGE         0x30
1195 #define IDETAPE_BUFFER_FILLING_PAGE     0x33
1196
1197 /*
1198  *      Mode Parameter Header for the MODE SENSE packet command
1199  */
1200 typedef struct {
1201         __u8    mode_data_length;       /* Length of the following data transfer */
1202         __u8    medium_type;            /* Medium Type */
1203         __u8    dsp;                    /* Device Specific Parameter */
1204         __u8    bdl;                    /* Block Descriptor Length */
1205 #if 0
1206         /* data transfer page */
1207         __u8    page_code       :6;
1208         __u8    reserved0_6     :1;
1209         __u8    ps              :1;     /* parameters saveable */
1210         __u8    page_length;            /* page Length == 0x02 */
1211         __u8    reserved2;
1212         __u8    read32k         :1;     /* 32k blk size (data only) */
1213         __u8    read32k5        :1;     /* 32.5k blk size (data&AUX) */
1214         __u8    reserved3_23    :2;
1215         __u8    write32k        :1;     /* 32k blk size (data only) */
1216         __u8    write32k5       :1;     /* 32.5k blk size (data&AUX) */
1217         __u8    reserved3_6     :1;
1218         __u8    streaming       :1;     /* streaming mode enable */
1219 #endif
1220 } idetape_mode_parameter_header_t;
1221
1222 /*
1223  *      Mode Parameter Block Descriptor the MODE SENSE packet command
1224  *
1225  *      Support for block descriptors is optional.
1226  */
1227 typedef struct {
1228         __u8            density_code;           /* Medium density code */
1229         __u8            blocks[3];              /* Number of blocks */
1230         __u8            reserved4;              /* Reserved */
1231         __u8            length[3];              /* Block Length */
1232 } idetape_parameter_block_descriptor_t;
1233
1234 /*
1235  *      The Data Compression Page, as returned by the MODE SENSE packet command.
1236  */
1237 typedef struct {
1238         unsigned        page_code       :6;     /* Page Code - Should be 0xf */
1239         unsigned        reserved0       :1;     /* Reserved */
1240         unsigned        ps              :1;
1241         __u8            page_length;            /* Page Length - Should be 14 */
1242         unsigned        reserved2       :6;     /* Reserved */
1243         unsigned        dcc             :1;     /* Data Compression Capable */
1244         unsigned        dce             :1;     /* Data Compression Enable */
1245         unsigned        reserved3       :5;     /* Reserved */
1246         unsigned        red             :2;     /* Report Exception on Decompression */
1247         unsigned        dde             :1;     /* Data Decompression Enable */
1248         __u32           ca;                     /* Compression Algorithm */
1249         __u32           da;                     /* Decompression Algorithm */
1250         __u8            reserved[4];            /* Reserved */
1251 } idetape_data_compression_page_t;
1252
1253 /*
1254  *      The Medium Partition Page, as returned by the MODE SENSE packet command.
1255  */
1256 typedef struct {
1257         unsigned        page_code       :6;     /* Page Code - Should be 0x11 */
1258         unsigned        reserved1_6     :1;     /* Reserved */
1259         unsigned        ps              :1;
1260         __u8            page_length;            /* Page Length - Should be 6 */
1261         __u8            map;                    /* Maximum Additional Partitions - Should be 0 */
1262         __u8            apd;                    /* Additional Partitions Defined - Should be 0 */
1263         unsigned        reserved4_012   :3;     /* Reserved */
1264         unsigned        psum            :2;     /* Should be 0 */
1265         unsigned        idp             :1;     /* Should be 0 */
1266         unsigned        sdp             :1;     /* Should be 0 */
1267         unsigned        fdp             :1;     /* Fixed Data Partitions */
1268         __u8            mfr;                    /* Medium Format Recognition */
1269         __u8            reserved[2];            /* Reserved */
1270 } idetape_medium_partition_page_t;
1271
1272 /*
1273  *      Run time configurable parameters.
1274  */
1275 typedef struct {
1276         int     dsc_rw_frequency;
1277         int     dsc_media_access_frequency;
1278         int     nr_stages;
1279 } idetape_config_t;
1280
1281 /*
1282  *      The variables below are used for the character device interface.
1283  *      Additional state variables are defined in our ide_drive_t structure.
1284  */
1285 static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
1286
1287 #define ide_tape_f(file) ((file)->private_data)
1288
1289 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
1290 {
1291         struct ide_tape_obj *tape = NULL;
1292
1293         mutex_lock(&idetape_ref_mutex);
1294         tape = idetape_devs[i];
1295         if (tape)
1296                 kref_get(&tape->kref);
1297         mutex_unlock(&idetape_ref_mutex);
1298         return tape;
1299 }
1300
1301 /*
1302  *      Function declarations
1303  *
1304  */
1305 static int idetape_chrdev_release (struct inode *inode, struct file *filp);
1306 static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
1307
1308 /*
1309  * Too bad. The drive wants to send us data which we are not ready to accept.
1310  * Just throw it away.
1311  */
1312 static void idetape_discard_data (ide_drive_t *drive, unsigned int bcount)
1313 {
1314         while (bcount--)
1315                 (void) HWIF(drive)->INB(IDE_DATA_REG);
1316 }
1317
1318 static void idetape_input_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1319 {
1320         struct idetape_bh *bh = pc->bh;
1321         int count;
1322
1323         while (bcount) {
1324 #if IDETAPE_DEBUG_BUGS
1325                 if (bh == NULL) {
1326                         printk(KERN_ERR "ide-tape: bh == NULL in "
1327                                 "idetape_input_buffers\n");
1328                         idetape_discard_data(drive, bcount);
1329                         return;
1330                 }
1331 #endif /* IDETAPE_DEBUG_BUGS */
1332                 count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), bcount);
1333                 HWIF(drive)->atapi_input_bytes(drive, bh->b_data + atomic_read(&bh->b_count), count);
1334                 bcount -= count;
1335                 atomic_add(count, &bh->b_count);
1336                 if (atomic_read(&bh->b_count) == bh->b_size) {
1337                         bh = bh->b_reqnext;
1338                         if (bh)
1339                                 atomic_set(&bh->b_count, 0);
1340                 }
1341         }
1342         pc->bh = bh;
1343 }
1344
1345 static void idetape_output_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1346 {
1347         struct idetape_bh *bh = pc->bh;
1348         int count;
1349
1350         while (bcount) {
1351 #if IDETAPE_DEBUG_BUGS
1352                 if (bh == NULL) {
1353                         printk(KERN_ERR "ide-tape: bh == NULL in "
1354                                 "idetape_output_buffers\n");
1355                         return;
1356                 }
1357 #endif /* IDETAPE_DEBUG_BUGS */
1358                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
1359                 HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
1360                 bcount -= count;
1361                 pc->b_data += count;
1362                 pc->b_count -= count;
1363                 if (!pc->b_count) {
1364                         pc->bh = bh = bh->b_reqnext;
1365                         if (bh) {
1366                                 pc->b_data = bh->b_data;
1367                                 pc->b_count = atomic_read(&bh->b_count);
1368                         }
1369                 }
1370         }
1371 }
1372
1373 static void idetape_update_buffers (idetape_pc_t *pc)
1374 {
1375         struct idetape_bh *bh = pc->bh;
1376         int count;
1377         unsigned int bcount = pc->actually_transferred;
1378
1379         if (test_bit(PC_WRITING, &pc->flags))
1380                 return;
1381         while (bcount) {
1382 #if IDETAPE_DEBUG_BUGS
1383                 if (bh == NULL) {
1384                         printk(KERN_ERR "ide-tape: bh == NULL in "
1385                                 "idetape_update_buffers\n");
1386                         return;
1387                 }
1388 #endif /* IDETAPE_DEBUG_BUGS */
1389                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
1390                 atomic_set(&bh->b_count, count);
1391                 if (atomic_read(&bh->b_count) == bh->b_size)
1392                         bh = bh->b_reqnext;
1393                 bcount -= count;
1394         }
1395         pc->bh = bh;
1396 }
1397
1398 /*
1399  *      idetape_next_pc_storage returns a pointer to a place in which we can
1400  *      safely store a packet command, even though we intend to leave the
1401  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
1402  *      commands is allocated at initialization time.
1403  */
1404 static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
1405 {
1406         idetape_tape_t *tape = drive->driver_data;
1407
1408 #if IDETAPE_DEBUG_LOG
1409         if (tape->debug_level >= 5)
1410                 printk(KERN_INFO "ide-tape: pc_stack_index=%d\n",
1411                         tape->pc_stack_index);
1412 #endif /* IDETAPE_DEBUG_LOG */
1413         if (tape->pc_stack_index == IDETAPE_PC_STACK)
1414                 tape->pc_stack_index=0;
1415         return (&tape->pc_stack[tape->pc_stack_index++]);
1416 }
1417
1418 /*
1419  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
1420  *      Since we queue packet commands in the request queue, we need to
1421  *      allocate a request, along with the allocation of a packet command.
1422  */
1423  
1424 /**************************************************************
1425  *                                                            *
1426  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
1427  *  followed later on by kfree().   -ml                       *
1428  *                                                            *
1429  **************************************************************/
1430  
1431 static struct request *idetape_next_rq_storage (ide_drive_t *drive)
1432 {
1433         idetape_tape_t *tape = drive->driver_data;
1434
1435 #if IDETAPE_DEBUG_LOG
1436         if (tape->debug_level >= 5)
1437                 printk(KERN_INFO "ide-tape: rq_stack_index=%d\n",
1438                         tape->rq_stack_index);
1439 #endif /* IDETAPE_DEBUG_LOG */
1440         if (tape->rq_stack_index == IDETAPE_PC_STACK)
1441                 tape->rq_stack_index=0;
1442         return (&tape->rq_stack[tape->rq_stack_index++]);
1443 }
1444
1445 /*
1446  *      idetape_init_pc initializes a packet command.
1447  */
1448 static void idetape_init_pc (idetape_pc_t *pc)
1449 {
1450         memset(pc->c, 0, 12);
1451         pc->retries = 0;
1452         pc->flags = 0;
1453         pc->request_transfer = 0;
1454         pc->buffer = pc->pc_buffer;
1455         pc->buffer_size = IDETAPE_PC_BUFFER_SIZE;
1456         pc->bh = NULL;
1457         pc->b_data = NULL;
1458 }
1459
1460 /*
1461  *      idetape_analyze_error is called on each failed packet command retry
1462  *      to analyze the request sense. We currently do not utilize this
1463  *      information.
1464  */
1465 static void idetape_analyze_error (ide_drive_t *drive, idetape_request_sense_result_t *result)
1466 {
1467         idetape_tape_t *tape = drive->driver_data;
1468         idetape_pc_t *pc = tape->failed_pc;
1469
1470         tape->sense     = *result;
1471         tape->sense_key = result->sense_key;
1472         tape->asc       = result->asc;
1473         tape->ascq      = result->ascq;
1474 #if IDETAPE_DEBUG_LOG
1475         /*
1476          *      Without debugging, we only log an error if we decided to
1477          *      give up retrying.
1478          */
1479         if (tape->debug_level >= 1)
1480                 printk(KERN_INFO "ide-tape: pc = %x, sense key = %x, "
1481                         "asc = %x, ascq = %x\n",
1482                         pc->c[0], result->sense_key,
1483                         result->asc, result->ascq);
1484 #endif /* IDETAPE_DEBUG_LOG */
1485
1486         /*
1487          *      Correct pc->actually_transferred by asking the tape.
1488          */
1489         if (test_bit(PC_DMA_ERROR, &pc->flags)) {
1490                 pc->actually_transferred = pc->request_transfer - tape->tape_block_size * ntohl(get_unaligned(&result->information));
1491                 idetape_update_buffers(pc);
1492         }
1493
1494         /*
1495          * If error was the result of a zero-length read or write command,
1496          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
1497          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
1498          */
1499         if ((pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD)
1500             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) { /* length==0 */
1501                 if (result->sense_key == 5) {
1502                         /* don't report an error, everything's ok */
1503                         pc->error = 0;
1504                         /* don't retry read/write */
1505                         set_bit(PC_ABORT, &pc->flags);
1506                 }
1507         }
1508         if (pc->c[0] == IDETAPE_READ_CMD && result->filemark) {
1509                 pc->error = IDETAPE_ERROR_FILEMARK;
1510                 set_bit(PC_ABORT, &pc->flags);
1511         }
1512         if (pc->c[0] == IDETAPE_WRITE_CMD) {
1513                 if (result->eom ||
1514                     (result->sense_key == 0xd && result->asc == 0x0 &&
1515                      result->ascq == 0x2)) {
1516                         pc->error = IDETAPE_ERROR_EOD;
1517                         set_bit(PC_ABORT, &pc->flags);
1518                 }
1519         }
1520         if (pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD) {
1521                 if (result->sense_key == 8) {
1522                         pc->error = IDETAPE_ERROR_EOD;
1523                         set_bit(PC_ABORT, &pc->flags);
1524                 }
1525                 if (!test_bit(PC_ABORT, &pc->flags) &&
1526                     pc->actually_transferred)
1527                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
1528         }
1529 }
1530
1531 /*
1532  * idetape_active_next_stage will declare the next stage as "active".
1533  */
1534 static void idetape_active_next_stage (ide_drive_t *drive)
1535 {
1536         idetape_tape_t *tape = drive->driver_data;
1537         idetape_stage_t *stage = tape->next_stage;
1538         struct request *rq = &stage->rq;
1539
1540 #if IDETAPE_DEBUG_LOG
1541         if (tape->debug_level >= 4)
1542                 printk(KERN_INFO "ide-tape: Reached idetape_active_next_stage\n");
1543 #endif /* IDETAPE_DEBUG_LOG */
1544 #if IDETAPE_DEBUG_BUGS
1545         if (stage == NULL) {
1546                 printk(KERN_ERR "ide-tape: bug: Trying to activate a non existing stage\n");
1547                 return;
1548         }
1549 #endif /* IDETAPE_DEBUG_BUGS */ 
1550
1551         rq->rq_disk = tape->disk;
1552         rq->buffer = NULL;
1553         rq->special = (void *)stage->bh;
1554         tape->active_data_request = rq;
1555         tape->active_stage = stage;
1556         tape->next_stage = stage->next;
1557 }
1558
1559 /*
1560  *      idetape_increase_max_pipeline_stages is a part of the feedback
1561  *      loop which tries to find the optimum number of stages. In the
1562  *      feedback loop, we are starting from a minimum maximum number of
1563  *      stages, and if we sense that the pipeline is empty, we try to
1564  *      increase it, until we reach the user compile time memory limit.
1565  */
1566 static void idetape_increase_max_pipeline_stages (ide_drive_t *drive)
1567 {
1568         idetape_tape_t *tape = drive->driver_data;
1569         int increase = (tape->max_pipeline - tape->min_pipeline) / 10;
1570         
1571 #if IDETAPE_DEBUG_LOG
1572         if (tape->debug_level >= 4)
1573                 printk (KERN_INFO "ide-tape: Reached idetape_increase_max_pipeline_stages\n");
1574 #endif /* IDETAPE_DEBUG_LOG */
1575
1576         tape->max_stages += max(increase, 1);
1577         tape->max_stages = max(tape->max_stages, tape->min_pipeline);
1578         tape->max_stages = min(tape->max_stages, tape->max_pipeline);
1579 }
1580
1581 /*
1582  *      idetape_kfree_stage calls kfree to completely free a stage, along with
1583  *      its related buffers.
1584  */
1585 static void __idetape_kfree_stage (idetape_stage_t *stage)
1586 {
1587         struct idetape_bh *prev_bh, *bh = stage->bh;
1588         int size;
1589
1590         while (bh != NULL) {
1591                 if (bh->b_data != NULL) {
1592                         size = (int) bh->b_size;
1593                         while (size > 0) {
1594                                 free_page((unsigned long) bh->b_data);
1595                                 size -= PAGE_SIZE;
1596                                 bh->b_data += PAGE_SIZE;
1597                         }
1598                 }
1599                 prev_bh = bh;
1600                 bh = bh->b_reqnext;
1601                 kfree(prev_bh);
1602         }
1603         kfree(stage);
1604 }
1605
1606 static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
1607 {
1608         __idetape_kfree_stage(stage);
1609 }
1610
1611 /*
1612  *      idetape_remove_stage_head removes tape->first_stage from the pipeline.
1613  *      The caller should avoid race conditions.
1614  */
1615 static void idetape_remove_stage_head (ide_drive_t *drive)
1616 {
1617         idetape_tape_t *tape = drive->driver_data;
1618         idetape_stage_t *stage;
1619         
1620 #if IDETAPE_DEBUG_LOG
1621         if (tape->debug_level >= 4)
1622                 printk(KERN_INFO "ide-tape: Reached idetape_remove_stage_head\n");
1623 #endif /* IDETAPE_DEBUG_LOG */
1624 #if IDETAPE_DEBUG_BUGS
1625         if (tape->first_stage == NULL) {
1626                 printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
1627                 return;         
1628         }
1629         if (tape->active_stage == tape->first_stage) {
1630                 printk(KERN_ERR "ide-tape: bug: Trying to free our active pipeline stage\n");
1631                 return;
1632         }
1633 #endif /* IDETAPE_DEBUG_BUGS */
1634         stage = tape->first_stage;
1635         tape->first_stage = stage->next;
1636         idetape_kfree_stage(tape, stage);
1637         tape->nr_stages--;
1638         if (tape->first_stage == NULL) {
1639                 tape->last_stage = NULL;
1640 #if IDETAPE_DEBUG_BUGS
1641                 if (tape->next_stage != NULL)
1642                         printk(KERN_ERR "ide-tape: bug: tape->next_stage != NULL\n");
1643                 if (tape->nr_stages)
1644                         printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 now\n");
1645 #endif /* IDETAPE_DEBUG_BUGS */
1646         }
1647 }
1648
1649 /*
1650  * This will free all the pipeline stages starting from new_last_stage->next
1651  * to the end of the list, and point tape->last_stage to new_last_stage.
1652  */
1653 static void idetape_abort_pipeline(ide_drive_t *drive,
1654                                    idetape_stage_t *new_last_stage)
1655 {
1656         idetape_tape_t *tape = drive->driver_data;
1657         idetape_stage_t *stage = new_last_stage->next;
1658         idetape_stage_t *nstage;
1659
1660 #if IDETAPE_DEBUG_LOG
1661         if (tape->debug_level >= 4)
1662                 printk(KERN_INFO "ide-tape: %s: idetape_abort_pipeline called\n", tape->name);
1663 #endif
1664         while (stage) {
1665                 nstage = stage->next;
1666                 idetape_kfree_stage(tape, stage);
1667                 --tape->nr_stages;
1668                 --tape->nr_pending_stages;
1669                 stage = nstage;
1670         }
1671         if (new_last_stage)
1672                 new_last_stage->next = NULL;
1673         tape->last_stage = new_last_stage;
1674         tape->next_stage = NULL;
1675 }
1676
1677 /*
1678  *      idetape_end_request is used to finish servicing a request, and to
1679  *      insert a pending pipeline request into the main device queue.
1680  */
1681 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
1682 {
1683         struct request *rq = HWGROUP(drive)->rq;
1684         idetape_tape_t *tape = drive->driver_data;
1685         unsigned long flags;
1686         int error;
1687         int remove_stage = 0;
1688         idetape_stage_t *active_stage;
1689
1690 #if IDETAPE_DEBUG_LOG
1691         if (tape->debug_level >= 4)
1692         printk(KERN_INFO "ide-tape: Reached idetape_end_request\n");
1693 #endif /* IDETAPE_DEBUG_LOG */
1694
1695         switch (uptodate) {
1696                 case 0: error = IDETAPE_ERROR_GENERAL; break;
1697                 case 1: error = 0; break;
1698                 default: error = uptodate;
1699         }
1700         rq->errors = error;
1701         if (error)
1702                 tape->failed_pc = NULL;
1703
1704         spin_lock_irqsave(&tape->spinlock, flags);
1705
1706         /* The request was a pipelined data transfer request */
1707         if (tape->active_data_request == rq) {
1708                 active_stage = tape->active_stage;
1709                 tape->active_stage = NULL;
1710                 tape->active_data_request = NULL;
1711                 tape->nr_pending_stages--;
1712                 if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1713                         remove_stage = 1;
1714                         if (error) {
1715                                 set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1716                                 if (error == IDETAPE_ERROR_EOD)
1717                                         idetape_abort_pipeline(drive, active_stage);
1718                         }
1719                 } else if (rq->cmd[0] & REQ_IDETAPE_READ) {
1720                         if (error == IDETAPE_ERROR_EOD) {
1721                                 set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1722                                 idetape_abort_pipeline(drive, active_stage);
1723                         }
1724                 }
1725                 if (tape->next_stage != NULL) {
1726                         idetape_active_next_stage(drive);
1727
1728                         /*
1729                          * Insert the next request into the request queue.
1730                          */
1731                         (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
1732                 } else if (!error) {
1733                                 idetape_increase_max_pipeline_stages(drive);
1734                 }
1735         }
1736         ide_end_drive_cmd(drive, 0, 0);
1737 //      blkdev_dequeue_request(rq);
1738 //      drive->rq = NULL;
1739 //      end_that_request_last(rq);
1740
1741         if (remove_stage)
1742                 idetape_remove_stage_head(drive);
1743         if (tape->active_data_request == NULL)
1744                 clear_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
1745         spin_unlock_irqrestore(&tape->spinlock, flags);
1746         return 0;
1747 }
1748
1749 static ide_startstop_t idetape_request_sense_callback (ide_drive_t *drive)
1750 {
1751         idetape_tape_t *tape = drive->driver_data;
1752
1753 #if IDETAPE_DEBUG_LOG
1754         if (tape->debug_level >= 4)
1755                 printk(KERN_INFO "ide-tape: Reached idetape_request_sense_callback\n");
1756 #endif /* IDETAPE_DEBUG_LOG */
1757         if (!tape->pc->error) {
1758                 idetape_analyze_error(drive, (idetape_request_sense_result_t *) tape->pc->buffer);
1759                 idetape_end_request(drive, 1, 0);
1760         } else {
1761                 printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - Aborting request!\n");
1762                 idetape_end_request(drive, 0, 0);
1763         }
1764         return ide_stopped;
1765 }
1766
1767 static void idetape_create_request_sense_cmd (idetape_pc_t *pc)
1768 {
1769         idetape_init_pc(pc);    
1770         pc->c[0] = IDETAPE_REQUEST_SENSE_CMD;
1771         pc->c[4] = 20;
1772         pc->request_transfer = 20;
1773         pc->callback = &idetape_request_sense_callback;
1774 }
1775
1776 static void idetape_init_rq(struct request *rq, u8 cmd)
1777 {
1778         memset(rq, 0, sizeof(*rq));
1779         rq->flags = REQ_SPECIAL;
1780         rq->cmd[0] = cmd;
1781 }
1782
1783 /*
1784  *      idetape_queue_pc_head generates a new packet command request in front
1785  *      of the request queue, before the current request, so that it will be
1786  *      processed immediately, on the next pass through the driver.
1787  *
1788  *      idetape_queue_pc_head is called from the request handling part of
1789  *      the driver (the "bottom" part). Safe storage for the request should
1790  *      be allocated with idetape_next_pc_storage and idetape_next_rq_storage
1791  *      before calling idetape_queue_pc_head.
1792  *
1793  *      Memory for those requests is pre-allocated at initialization time, and
1794  *      is limited to IDETAPE_PC_STACK requests. We assume that we have enough
1795  *      space for the maximum possible number of inter-dependent packet commands.
1796  *
1797  *      The higher level of the driver - The ioctl handler and the character
1798  *      device handling functions should queue request to the lower level part
1799  *      and wait for their completion using idetape_queue_pc_tail or
1800  *      idetape_queue_rw_tail.
1801  */
1802 static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
1803 {
1804         struct ide_tape_obj *tape = drive->driver_data;
1805
1806         idetape_init_rq(rq, REQ_IDETAPE_PC1);
1807         rq->buffer = (char *) pc;
1808         rq->rq_disk = tape->disk;
1809         (void) ide_do_drive_cmd(drive, rq, ide_preempt);
1810 }
1811
1812 /*
1813  *      idetape_retry_pc is called when an error was detected during the
1814  *      last packet command. We queue a request sense packet command in
1815  *      the head of the request list.
1816  */
1817 static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
1818 {
1819         idetape_tape_t *tape = drive->driver_data;
1820         idetape_pc_t *pc;
1821         struct request *rq;
1822         atapi_error_t error;
1823
1824         error.all = HWIF(drive)->INB(IDE_ERROR_REG);
1825         pc = idetape_next_pc_storage(drive);
1826         rq = idetape_next_rq_storage(drive);
1827         idetape_create_request_sense_cmd(pc);
1828         set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
1829         idetape_queue_pc_head(drive, pc, rq);
1830         return ide_stopped;
1831 }
1832
1833 /*
1834  *      idetape_postpone_request postpones the current request so that
1835  *      ide.c will be able to service requests from another device on
1836  *      the same hwgroup while we are polling for DSC.
1837  */
1838 static void idetape_postpone_request (ide_drive_t *drive)
1839 {
1840         idetape_tape_t *tape = drive->driver_data;
1841
1842 #if IDETAPE_DEBUG_LOG
1843         if (tape->debug_level >= 4)
1844                 printk(KERN_INFO "ide-tape: idetape_postpone_request\n");
1845 #endif
1846         tape->postponed_rq = HWGROUP(drive)->rq;
1847         ide_stall_queue(drive, tape->dsc_polling_frequency);
1848 }
1849
1850 /*
1851  *      idetape_pc_intr is the usual interrupt handler which will be called
1852  *      during a packet command. We will transfer some of the data (as
1853  *      requested by the drive) and will re-point interrupt handler to us.
1854  *      When data transfer is finished, we will act according to the
1855  *      algorithm described before idetape_issue_packet_command.
1856  *
1857  */
1858 static ide_startstop_t idetape_pc_intr (ide_drive_t *drive)
1859 {
1860         ide_hwif_t *hwif = drive->hwif;
1861         idetape_tape_t *tape = drive->driver_data;
1862         atapi_status_t status;
1863         atapi_bcount_t bcount;
1864         atapi_ireason_t ireason;
1865         idetape_pc_t *pc = tape->pc;
1866
1867         unsigned int temp;
1868 #if SIMULATE_ERRORS
1869         static int error_sim_count = 0;
1870 #endif
1871
1872 #if IDETAPE_DEBUG_LOG
1873         if (tape->debug_level >= 4)
1874                 printk(KERN_INFO "ide-tape: Reached idetape_pc_intr "
1875                                 "interrupt handler\n");
1876 #endif /* IDETAPE_DEBUG_LOG */  
1877
1878         /* Clear the interrupt */
1879         status.all = HWIF(drive)->INB(IDE_STATUS_REG);
1880
1881         if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1882                 if (HWIF(drive)->ide_dma_end(drive) || status.b.check) {
1883                         /*
1884                          * A DMA error is sometimes expected. For example,
1885                          * if the tape is crossing a filemark during a
1886                          * READ command, it will issue an irq and position
1887                          * itself before the filemark, so that only a partial
1888                          * data transfer will occur (which causes the DMA
1889                          * error). In that case, we will later ask the tape
1890                          * how much bytes of the original request were
1891                          * actually transferred (we can't receive that
1892                          * information from the DMA engine on most chipsets).
1893                          */
1894
1895                         /*
1896                          * On the contrary, a DMA error is never expected;
1897                          * it usually indicates a hardware error or abort.
1898                          * If the tape crosses a filemark during a READ
1899                          * command, it will issue an irq and position itself
1900                          * after the filemark (not before). Only a partial
1901                          * data transfer will occur, but no DMA error.
1902                          * (AS, 19 Apr 2001)
1903                          */
1904                         set_bit(PC_DMA_ERROR, &pc->flags);
1905                 } else {
1906                         pc->actually_transferred = pc->request_transfer;
1907                         idetape_update_buffers(pc);
1908                 }
1909 #if IDETAPE_DEBUG_LOG
1910                 if (tape->debug_level >= 4)
1911                         printk(KERN_INFO "ide-tape: DMA finished\n");
1912 #endif /* IDETAPE_DEBUG_LOG */
1913         }
1914
1915         /* No more interrupts */
1916         if (!status.b.drq) {
1917 #if IDETAPE_DEBUG_LOG
1918                 if (tape->debug_level >= 2)
1919                         printk(KERN_INFO "ide-tape: Packet command completed, %d bytes transferred\n", pc->actually_transferred);
1920 #endif /* IDETAPE_DEBUG_LOG */
1921                 clear_bit(PC_DMA_IN_PROGRESS, &pc->flags);
1922
1923                 local_irq_enable();
1924
1925 #if SIMULATE_ERRORS
1926                 if ((pc->c[0] == IDETAPE_WRITE_CMD ||
1927                      pc->c[0] == IDETAPE_READ_CMD) &&
1928                     (++error_sim_count % 100) == 0) {
1929                         printk(KERN_INFO "ide-tape: %s: simulating error\n",
1930                                 tape->name);
1931                         status.b.check = 1;
1932                 }
1933 #endif
1934                 if (status.b.check && pc->c[0] == IDETAPE_REQUEST_SENSE_CMD)
1935                         status.b.check = 0;
1936                 if (status.b.check || test_bit(PC_DMA_ERROR, &pc->flags)) {     /* Error detected */
1937 #if IDETAPE_DEBUG_LOG
1938                         if (tape->debug_level >= 1)
1939                                 printk(KERN_INFO "ide-tape: %s: I/O error\n",
1940                                         tape->name);
1941 #endif /* IDETAPE_DEBUG_LOG */
1942                         if (pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
1943                                 printk(KERN_ERR "ide-tape: I/O error in request sense command\n");
1944                                 return ide_do_reset(drive);
1945                         }
1946 #if IDETAPE_DEBUG_LOG
1947                         if (tape->debug_level >= 1)
1948                                 printk(KERN_INFO "ide-tape: [cmd %x]: check condition\n", pc->c[0]);
1949 #endif
1950                         /* Retry operation */
1951                         return idetape_retry_pc(drive);
1952                 }
1953                 pc->error = 0;
1954                 if (test_bit(PC_WAIT_FOR_DSC, &pc->flags) &&
1955                     !status.b.dsc) {
1956                         /* Media access command */
1957                         tape->dsc_polling_start = jiffies;
1958                         tape->dsc_polling_frequency = IDETAPE_DSC_MA_FAST;
1959                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
1960                         /* Allow ide.c to handle other requests */
1961                         idetape_postpone_request(drive);
1962                         return ide_stopped;
1963                 }
1964                 if (tape->failed_pc == pc)
1965                         tape->failed_pc = NULL;
1966                 /* Command finished - Call the callback function */
1967                 return pc->callback(drive);
1968         }
1969         if (test_and_clear_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1970                 printk(KERN_ERR "ide-tape: The tape wants to issue more "
1971                                 "interrupts in DMA mode\n");
1972                 printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1973                 (void)__ide_dma_off(drive);
1974                 return ide_do_reset(drive);
1975         }
1976         /* Get the number of bytes to transfer on this interrupt. */
1977         bcount.b.high = hwif->INB(IDE_BCOUNTH_REG);
1978         bcount.b.low = hwif->INB(IDE_BCOUNTL_REG);
1979
1980         ireason.all = hwif->INB(IDE_IREASON_REG);
1981
1982         if (ireason.b.cod) {
1983                 printk(KERN_ERR "ide-tape: CoD != 0 in idetape_pc_intr\n");
1984                 return ide_do_reset(drive);
1985         }
1986         if (ireason.b.io == test_bit(PC_WRITING, &pc->flags)) {
1987                 /* Hopefully, we will never get here */
1988                 printk(KERN_ERR "ide-tape: We wanted to %s, ",
1989                         ireason.b.io ? "Write":"Read");
1990                 printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1991                         ireason.b.io ? "Read":"Write");
1992                 return ide_do_reset(drive);
1993         }
1994         if (!test_bit(PC_WRITING, &pc->flags)) {
1995                 /* Reading - Check that we have enough space */
1996                 temp = pc->actually_transferred + bcount.all;
1997                 if (temp > pc->request_transfer) {
1998                         if (temp > pc->buffer_size) {
1999                                 printk(KERN_ERR "ide-tape: The tape wants to send us more data than expected - discarding data\n");
2000                                 idetape_discard_data(drive, bcount.all);
2001                                 ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2002                                 return ide_started;
2003                         }
2004 #if IDETAPE_DEBUG_LOG
2005                         if (tape->debug_level >= 2)
2006                                 printk(KERN_NOTICE "ide-tape: The tape wants to send us more data than expected - allowing transfer\n");
2007 #endif /* IDETAPE_DEBUG_LOG */
2008                 }
2009         }
2010         if (test_bit(PC_WRITING, &pc->flags)) {
2011                 if (pc->bh != NULL)
2012                         idetape_output_buffers(drive, pc, bcount.all);
2013                 else
2014                         /* Write the current buffer */
2015                         HWIF(drive)->atapi_output_bytes(drive, pc->current_position, bcount.all);
2016         } else {
2017                 if (pc->bh != NULL)
2018                         idetape_input_buffers(drive, pc, bcount.all);
2019                 else
2020                         /* Read the current buffer */
2021                         HWIF(drive)->atapi_input_bytes(drive, pc->current_position, bcount.all);
2022         }
2023         /* Update the current position */
2024         pc->actually_transferred += bcount.all;
2025         pc->current_position += bcount.all;
2026 #if IDETAPE_DEBUG_LOG
2027         if (tape->debug_level >= 2)
2028                 printk(KERN_INFO "ide-tape: [cmd %x] transferred %d bytes on that interrupt\n", pc->c[0], bcount.all);
2029 #endif
2030         /* And set the interrupt handler again */
2031         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2032         return ide_started;
2033 }
2034
2035 /*
2036  *      Packet Command Interface
2037  *
2038  *      The current Packet Command is available in tape->pc, and will not
2039  *      change until we finish handling it. Each packet command is associated
2040  *      with a callback function that will be called when the command is
2041  *      finished.
2042  *
2043  *      The handling will be done in three stages:
2044  *
2045  *      1.      idetape_issue_packet_command will send the packet command to the
2046  *              drive, and will set the interrupt handler to idetape_pc_intr.
2047  *
2048  *      2.      On each interrupt, idetape_pc_intr will be called. This step
2049  *              will be repeated until the device signals us that no more
2050  *              interrupts will be issued.
2051  *
2052  *      3.      ATAPI Tape media access commands have immediate status with a
2053  *              delayed process. In case of a successful initiation of a
2054  *              media access packet command, the DSC bit will be set when the
2055  *              actual execution of the command is finished. 
2056  *              Since the tape drive will not issue an interrupt, we have to
2057  *              poll for this event. In this case, we define the request as
2058  *              "low priority request" by setting rq_status to
2059  *              IDETAPE_RQ_POSTPONED,   set a timer to poll for DSC and exit
2060  *              the driver.
2061  *
2062  *              ide.c will then give higher priority to requests which
2063  *              originate from the other device, until will change rq_status
2064  *              to RQ_ACTIVE.
2065  *
2066  *      4.      When the packet command is finished, it will be checked for errors.
2067  *
2068  *      5.      In case an error was found, we queue a request sense packet
2069  *              command in front of the request queue and retry the operation
2070  *              up to IDETAPE_MAX_PC_RETRIES times.
2071  *
2072  *      6.      In case no error was found, or we decided to give up and not
2073  *              to retry again, the callback function will be called and then
2074  *              we will handle the next request.
2075  *
2076  */
2077 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
2078 {
2079         ide_hwif_t *hwif = drive->hwif;
2080         idetape_tape_t *tape = drive->driver_data;
2081         idetape_pc_t *pc = tape->pc;
2082         atapi_ireason_t ireason;
2083         int retries = 100;
2084         ide_startstop_t startstop;
2085
2086         if (ide_wait_stat(&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
2087                 printk(KERN_ERR "ide-tape: Strange, packet command initiated yet DRQ isn't asserted\n");
2088                 return startstop;
2089         }
2090         ireason.all = hwif->INB(IDE_IREASON_REG);
2091         while (retries-- && (!ireason.b.cod || ireason.b.io)) {
2092                 printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
2093                                 "a packet command, retrying\n");
2094                 udelay(100);
2095                 ireason.all = hwif->INB(IDE_IREASON_REG);
2096                 if (retries == 0) {
2097                         printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
2098                                         "issuing a packet command, ignoring\n");
2099                         ireason.b.cod = 1;
2100                         ireason.b.io = 0;
2101                 }
2102         }
2103         if (!ireason.b.cod || ireason.b.io) {
2104                 printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
2105                                 "a packet command\n");
2106                 return ide_do_reset(drive);
2107         }
2108         /* Set the interrupt routine */
2109         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2110 #ifdef CONFIG_BLK_DEV_IDEDMA
2111         /* Begin DMA, if necessary */
2112         if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags))
2113                 hwif->dma_start(drive);
2114 #endif
2115         /* Send the actual packet */
2116         HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
2117         return ide_started;
2118 }
2119
2120 static ide_startstop_t idetape_issue_packet_command (ide_drive_t *drive, idetape_pc_t *pc)
2121 {
2122         ide_hwif_t *hwif = drive->hwif;
2123         idetape_tape_t *tape = drive->driver_data;
2124         atapi_bcount_t bcount;
2125         int dma_ok = 0;
2126
2127 #if IDETAPE_DEBUG_BUGS
2128         if (tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD &&
2129             pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2130                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
2131                         "Two request sense in serial were issued\n");
2132         }
2133 #endif /* IDETAPE_DEBUG_BUGS */
2134
2135         if (tape->failed_pc == NULL && pc->c[0] != IDETAPE_REQUEST_SENSE_CMD)
2136                 tape->failed_pc = pc;
2137         /* Set the current packet command */
2138         tape->pc = pc;
2139
2140         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
2141             test_bit(PC_ABORT, &pc->flags)) {
2142                 /*
2143                  *      We will "abort" retrying a packet command in case
2144                  *      a legitimate error code was received (crossing a
2145                  *      filemark, or end of the media, for example).
2146                  */
2147                 if (!test_bit(PC_ABORT, &pc->flags)) {
2148                         if (!(pc->c[0] == IDETAPE_TEST_UNIT_READY_CMD &&
2149                               tape->sense_key == 2 && tape->asc == 4 &&
2150                              (tape->ascq == 1 || tape->ascq == 8))) {
2151                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
2152                                                 "pc = %2x, key = %2x, "
2153                                                 "asc = %2x, ascq = %2x\n",
2154                                                 tape->name, pc->c[0],
2155                                                 tape->sense_key, tape->asc,
2156                                                 tape->ascq);
2157                         }
2158                         /* Giving up */
2159                         pc->error = IDETAPE_ERROR_GENERAL;
2160                 }
2161                 tape->failed_pc = NULL;
2162                 return pc->callback(drive);
2163         }
2164 #if IDETAPE_DEBUG_LOG
2165         if (tape->debug_level >= 2)
2166                 printk(KERN_INFO "ide-tape: Retry number - %d, cmd = %02X\n", pc->retries, pc->c[0]);
2167 #endif /* IDETAPE_DEBUG_LOG */
2168
2169         pc->retries++;
2170         /* We haven't transferred any data yet */
2171         pc->actually_transferred = 0;
2172         pc->current_position = pc->buffer;
2173         /* Request to transfer the entire buffer at once */
2174         bcount.all = pc->request_transfer;
2175
2176         if (test_and_clear_bit(PC_DMA_ERROR, &pc->flags)) {
2177                 printk(KERN_WARNING "ide-tape: DMA disabled, "
2178                                 "reverting to PIO\n");
2179                 (void)__ide_dma_off(drive);
2180         }
2181         if (test_bit(PC_DMA_RECOMMENDED, &pc->flags) && drive->using_dma)
2182                 dma_ok = !hwif->dma_setup(drive);
2183
2184         if (IDE_CONTROL_REG)
2185                 hwif->OUTB(drive->ctl, IDE_CONTROL_REG);
2186         hwif->OUTB(dma_ok ? 1 : 0, IDE_FEATURE_REG);    /* Use PIO/DMA */
2187         hwif->OUTB(bcount.b.high, IDE_BCOUNTH_REG);
2188         hwif->OUTB(bcount.b.low, IDE_BCOUNTL_REG);
2189         hwif->OUTB(drive->select.all, IDE_SELECT_REG);
2190         if (dma_ok)                     /* Will begin DMA later */
2191                 set_bit(PC_DMA_IN_PROGRESS, &pc->flags);
2192         if (test_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags)) {
2193                 ide_set_handler(drive, &idetape_transfer_pc, IDETAPE_WAIT_CMD, NULL);
2194                 hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2195                 return ide_started;
2196         } else {
2197                 hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2198                 return idetape_transfer_pc(drive);
2199         }
2200 }
2201
2202 /*
2203  *      General packet command callback function.
2204  */
2205 static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
2206 {
2207         idetape_tape_t *tape = drive->driver_data;
2208         
2209 #if IDETAPE_DEBUG_LOG
2210         if (tape->debug_level >= 4)
2211                 printk(KERN_INFO "ide-tape: Reached idetape_pc_callback\n");
2212 #endif /* IDETAPE_DEBUG_LOG */
2213
2214         idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
2215         return ide_stopped;
2216 }
2217
2218 /*
2219  *      A mode sense command is used to "sense" tape parameters.
2220  */
2221 static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
2222 {
2223         idetape_init_pc(pc);
2224         pc->c[0] = IDETAPE_MODE_SENSE_CMD;
2225         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
2226                 pc->c[1] = 8;   /* DBD = 1 - Don't return block descriptors */
2227         pc->c[2] = page_code;
2228         /*
2229          * Changed pc->c[3] to 0 (255 will at best return unused info).
2230          *
2231          * For SCSI this byte is defined as subpage instead of high byte
2232          * of length and some IDE drives seem to interpret it this way
2233          * and return an error when 255 is used.
2234          */
2235         pc->c[3] = 0;
2236         pc->c[4] = 255;         /* (We will just discard data in that case) */
2237         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
2238                 pc->request_transfer = 12;
2239         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
2240                 pc->request_transfer = 24;
2241         else
2242                 pc->request_transfer = 50;
2243         pc->callback = &idetape_pc_callback;
2244 }
2245
2246 static void calculate_speeds(ide_drive_t *drive)
2247 {
2248         idetape_tape_t *tape = drive->driver_data;
2249         int full = 125, empty = 75;
2250
2251         if (time_after(jiffies, tape->controlled_pipeline_head_time + 120 * HZ)) {
2252                 tape->controlled_previous_pipeline_head = tape->controlled_last_pipeline_head;
2253                 tape->controlled_previous_head_time = tape->controlled_pipeline_head_time;
2254                 tape->controlled_last_pipeline_head = tape->pipeline_head;
2255                 tape->controlled_pipeline_head_time = jiffies;
2256         }
2257         if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
2258                 tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_last_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_pipeline_head_time);
2259         else if (time_after(jiffies, tape->controlled_previous_head_time))
2260                 tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_previous_head_time);
2261
2262         if (tape->nr_pending_stages < tape->max_stages /*- 1 */) {
2263                 /* -1 for read mode error recovery */
2264                 if (time_after(jiffies, tape->uncontrolled_previous_head_time + 10 * HZ)) {
2265                         tape->uncontrolled_pipeline_head_time = jiffies;
2266                         tape->uncontrolled_pipeline_head_speed = (tape->pipeline_head - tape->uncontrolled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->uncontrolled_previous_head_time);
2267                 }
2268         } else {
2269                 tape->uncontrolled_previous_head_time = jiffies;
2270                 tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
2271                 if (time_after(jiffies, tape->uncontrolled_pipeline_head_time + 30 * HZ)) {
2272                         tape->uncontrolled_pipeline_head_time = jiffies;
2273                 }
2274         }
2275         tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed, tape->controlled_pipeline_head_speed);
2276         if (tape->speed_control == 0) {
2277                 tape->max_insert_speed = 5000;
2278         } else if (tape->speed_control == 1) {
2279                 if (tape->nr_pending_stages >= tape->max_stages / 2)
2280                         tape->max_insert_speed = tape->pipeline_head_speed +
2281                                 (1100 - tape->pipeline_head_speed) * 2 * (tape->nr_pending_stages - tape->max_stages / 2) / tape->max_stages;
2282                 else
2283                         tape->max_insert_speed = 500 +
2284                                 (tape->pipeline_head_speed - 500) * 2 * tape->nr_pending_stages / tape->max_stages;
2285                 if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
2286                         tape->max_insert_speed = 5000;
2287         } else if (tape->speed_control == 2) {
2288                 tape->max_insert_speed = tape->pipeline_head_speed * empty / 100 +
2289                         (tape->pipeline_head_speed * full / 100 - tape->pipeline_head_speed * empty / 100) * tape->nr_pending_stages / tape->max_stages;
2290         } else
2291                 tape->max_insert_speed = tape->speed_control;
2292         tape->max_insert_speed = max(tape->max_insert_speed, 500);
2293 }
2294
2295 static ide_startstop_t idetape_media_access_finished (ide_drive_t *drive)
2296 {
2297         idetape_tape_t *tape = drive->driver_data;
2298         idetape_pc_t *pc = tape->pc;
2299         atapi_status_t status;
2300
2301         status.all = HWIF(drive)->INB(IDE_STATUS_REG);
2302         if (status.b.dsc) {
2303                 if (status.b.check) {
2304                         /* Error detected */
2305                         if (pc->c[0] != IDETAPE_TEST_UNIT_READY_CMD)
2306                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
2307                                                 tape->name);
2308                         /* Retry operation */
2309                         return idetape_retry_pc(drive);
2310                 }
2311                 pc->error = 0;
2312                 if (tape->failed_pc == pc)
2313                         tape->failed_pc = NULL;
2314         } else {
2315                 pc->error = IDETAPE_ERROR_GENERAL;
2316                 tape->failed_pc = NULL;
2317         }
2318         return pc->callback(drive);
2319 }
2320
2321 static ide_startstop_t idetape_rw_callback (ide_drive_t *drive)
2322 {
2323         idetape_tape_t *tape = drive->driver_data;
2324         struct request *rq = HWGROUP(drive)->rq;
2325         int blocks = tape->pc->actually_transferred / tape->tape_block_size;
2326
2327         tape->avg_size += blocks * tape->tape_block_size;
2328         tape->insert_size += blocks * tape->tape_block_size;
2329         if (tape->insert_size > 1024 * 1024)
2330                 tape->measure_insert_time = 1;
2331         if (tape->measure_insert_time) {
2332                 tape->measure_insert_time = 0;
2333                 tape->insert_time = jiffies;
2334                 tape->insert_size = 0;
2335         }
2336         if (time_after(jiffies, tape->insert_time))
2337                 tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2338         if (time_after_eq(jiffies, tape->avg_time + HZ)) {
2339                 tape->avg_speed = tape->avg_size * HZ / (jiffies - tape->avg_time) / 1024;
2340                 tape->avg_size = 0;
2341                 tape->avg_time = jiffies;
2342         }
2343
2344 #if IDETAPE_DEBUG_LOG   
2345         if (tape->debug_level >= 4)
2346                 printk(KERN_INFO "ide-tape: Reached idetape_rw_callback\n");
2347 #endif /* IDETAPE_DEBUG_LOG */
2348
2349         tape->first_frame_position += blocks;
2350         rq->current_nr_sectors -= blocks;
2351
2352         if (!tape->pc->error)
2353                 idetape_end_request(drive, 1, 0);
2354         else
2355                 idetape_end_request(drive, tape->pc->error, 0);
2356         return ide_stopped;
2357 }
2358
2359 static void idetape_create_read_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2360 {
2361         idetape_init_pc(pc);
2362         pc->c[0] = IDETAPE_READ_CMD;
2363         put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2364         pc->c[1] = 1;
2365         pc->callback = &idetape_rw_callback;
2366         pc->bh = bh;
2367         atomic_set(&bh->b_count, 0);
2368         pc->buffer = NULL;
2369         pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2370         if (pc->request_transfer == tape->stage_size)
2371                 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2372 }
2373
2374 static void idetape_create_read_buffer_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2375 {
2376         int size = 32768;
2377         struct idetape_bh *p = bh;
2378
2379         idetape_init_pc(pc);
2380         pc->c[0] = IDETAPE_READ_BUFFER_CMD;
2381         pc->c[1] = IDETAPE_RETRIEVE_FAULTY_BLOCK;
2382         pc->c[7] = size >> 8;
2383         pc->c[8] = size & 0xff;
2384         pc->callback = &idetape_pc_callback;
2385         pc->bh = bh;
2386         atomic_set(&bh->b_count, 0);
2387         pc->buffer = NULL;
2388         while (p) {
2389                 atomic_set(&p->b_count, 0);
2390                 p = p->b_reqnext;
2391         }
2392         pc->request_transfer = pc->buffer_size = size;
2393 }
2394
2395 static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2396 {
2397         idetape_init_pc(pc);
2398         pc->c[0] = IDETAPE_WRITE_CMD;
2399         put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2400         pc->c[1] = 1;
2401         pc->callback = &idetape_rw_callback;
2402         set_bit(PC_WRITING, &pc->flags);
2403         pc->bh = bh;
2404         pc->b_data = bh->b_data;
2405         pc->b_count = atomic_read(&bh->b_count);
2406         pc->buffer = NULL;
2407         pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2408         if (pc->request_transfer == tape->stage_size)
2409                 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2410 }
2411
2412 /*
2413  * idetape_do_request is our request handling function. 
2414  */
2415 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
2416                                           struct request *rq, sector_t block)
2417 {
2418         idetape_tape_t *tape = drive->driver_data;
2419         idetape_pc_t *pc = NULL;
2420         struct request *postponed_rq = tape->postponed_rq;
2421         atapi_status_t status;
2422
2423 #if IDETAPE_DEBUG_LOG
2424 #if 0
2425         if (tape->debug_level >= 5)
2426                 printk(KERN_INFO "ide-tape: rq_status: %d, "
2427                         "dev: %s, cmd: %ld, errors: %d\n", rq->rq_status,
2428                          rq->rq_disk->disk_name, rq->cmd[0], rq->errors);
2429 #endif
2430         if (tape->debug_level >= 2)
2431                 printk(KERN_INFO "ide-tape: sector: %ld, "
2432                         "nr_sectors: %ld, current_nr_sectors: %d\n",
2433                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
2434 #endif /* IDETAPE_DEBUG_LOG */
2435
2436         if ((rq->flags & REQ_SPECIAL) == 0) {
2437                 /*
2438                  * We do not support buffer cache originated requests.
2439                  */
2440                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
2441                         "request queue (%ld)\n", drive->name, rq->flags);
2442                 ide_end_request(drive, 0, 0);
2443                 return ide_stopped;
2444         }
2445
2446         /*
2447          *      Retry a failed packet command
2448          */
2449         if (tape->failed_pc != NULL &&
2450             tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2451                 return idetape_issue_packet_command(drive, tape->failed_pc);
2452         }
2453 #if IDETAPE_DEBUG_BUGS
2454         if (postponed_rq != NULL)
2455                 if (rq != postponed_rq) {
2456                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
2457                                         "Two DSC requests were queued\n");
2458                         idetape_end_request(drive, 0, 0);
2459                         return ide_stopped;
2460                 }
2461 #endif /* IDETAPE_DEBUG_BUGS */
2462
2463         tape->postponed_rq = NULL;
2464
2465         /*
2466          * If the tape is still busy, postpone our request and service
2467          * the other device meanwhile.
2468          */
2469         status.all = HWIF(drive)->INB(IDE_STATUS_REG);
2470
2471         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
2472                 set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2473
2474         if (drive->post_reset == 1) {
2475                 set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2476                 drive->post_reset = 0;
2477         }
2478
2479         if (tape->tape_still_time > 100 && tape->tape_still_time < 200)
2480                 tape->measure_insert_time = 1;
2481         if (time_after(jiffies, tape->insert_time))
2482                 tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2483         calculate_speeds(drive);
2484         if (!test_and_clear_bit(IDETAPE_IGNORE_DSC, &tape->flags) &&
2485             !status.b.dsc) {
2486                 if (postponed_rq == NULL) {
2487                         tape->dsc_polling_start = jiffies;
2488                         tape->dsc_polling_frequency = tape->best_dsc_rw_frequency;
2489                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
2490                 } else if (time_after(jiffies, tape->dsc_timeout)) {
2491                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
2492                                 tape->name);
2493                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2494                                 idetape_media_access_finished(drive);
2495                                 return ide_stopped;
2496                         } else {
2497                                 return ide_do_reset(drive);
2498                         }
2499                 } else if (time_after(jiffies, tape->dsc_polling_start + IDETAPE_DSC_MA_THRESHOLD))
2500                         tape->dsc_polling_frequency = IDETAPE_DSC_MA_SLOW;
2501                 idetape_postpone_request(drive);
2502                 return ide_stopped;
2503         }
2504         if (rq->cmd[0] & REQ_IDETAPE_READ) {
2505                 tape->buffer_head++;
2506 #if USE_IOTRACE
2507                 IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
2508 #endif
2509                 tape->postpone_cnt = 0;
2510                 pc = idetape_next_pc_storage(drive);
2511                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2512                 goto out;
2513         }
2514         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
2515                 tape->buffer_head++;
2516 #if USE_IOTRACE
2517                 IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
2518 #endif
2519                 tape->postpone_cnt = 0;
2520                 pc = idetape_next_pc_storage(drive);
2521                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2522                 goto out;
2523         }
2524         if (rq->cmd[0] & REQ_IDETAPE_READ_BUFFER) {
2525                 tape->postpone_cnt = 0;
2526                 pc = idetape_next_pc_storage(drive);
2527                 idetape_create_read_buffer_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2528                 goto out;
2529         }
2530         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
2531                 pc = (idetape_pc_t *) rq->buffer;
2532                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
2533                 rq->cmd[0] |= REQ_IDETAPE_PC2;
2534                 goto out;
2535         }
2536         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2537                 idetape_media_access_finished(drive);
2538                 return ide_stopped;
2539         }
2540         BUG();
2541 out:
2542         return idetape_issue_packet_command(drive, pc);
2543 }
2544
2545 /*
2546  *      Pipeline related functions
2547  */
2548 static inline int idetape_pipeline_active (idetape_tape_t *tape)
2549 {
2550         int rc1, rc2;
2551
2552         rc1 = test_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
2553         rc2 = (tape->active_data_request != NULL);
2554         return rc1;
2555 }
2556
2557 /*
2558  *      idetape_kmalloc_stage uses __get_free_page to allocate a pipeline
2559  *      stage, along with all the necessary small buffers which together make
2560  *      a buffer of size tape->stage_size (or a bit more). We attempt to
2561  *      combine sequential pages as much as possible.
2562  *
2563  *      Returns a pointer to the new allocated stage, or NULL if we
2564  *      can't (or don't want to) allocate a stage.
2565  *
2566  *      Pipeline stages are optional and are used to increase performance.
2567  *      If we can't allocate them, we'll manage without them.
2568  */
2569 static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
2570 {
2571         idetape_stage_t *stage;
2572         struct idetape_bh *prev_bh, *bh;
2573         int pages = tape->pages_per_stage;
2574         char *b_data = NULL;
2575
2576         if ((stage = (idetape_stage_t *) kmalloc (sizeof (idetape_stage_t),GFP_KERNEL)) == NULL)
2577                 return NULL;
2578         stage->next = NULL;
2579
2580         bh = stage->bh = (struct idetape_bh *)kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
2581         if (bh == NULL)
2582                 goto abort;
2583         bh->b_reqnext = NULL;
2584         if ((bh->b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2585                 goto abort;
2586         if (clear)
2587                 memset(bh->b_data, 0, PAGE_SIZE);
2588         bh->b_size = PAGE_SIZE;
2589         atomic_set(&bh->b_count, full ? bh->b_size : 0);
2590
2591         while (--pages) {
2592                 if ((b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2593                         goto abort;
2594                 if (clear)
2595                         memset(b_data, 0, PAGE_SIZE);
2596                 if (bh->b_data == b_data + PAGE_SIZE) {
2597                         bh->b_size += PAGE_SIZE;
2598                         bh->b_data -= PAGE_SIZE;
2599                         if (full)
2600                                 atomic_add(PAGE_SIZE, &bh->b_count);
2601                         continue;
2602                 }
2603                 if (b_data == bh->b_data + bh->b_size) {
2604                         bh->b_size += PAGE_SIZE;
2605                         if (full)
2606                                 atomic_add(PAGE_SIZE, &bh->b_count);
2607                         continue;
2608                 }
2609                 prev_bh = bh;
2610                 if ((bh = (struct idetape_bh *)kmalloc(sizeof(struct idetape_bh), GFP_KERNEL)) == NULL) {
2611                         free_page((unsigned long) b_data);
2612                         goto abort;
2613                 }
2614                 bh->b_reqnext = NULL;
2615                 bh->b_data = b_data;
2616                 bh->b_size = PAGE_SIZE;
2617                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
2618                 prev_bh->b_reqnext = bh;
2619         }
2620         bh->b_size -= tape->excess_bh_size;
2621         if (full)
2622                 atomic_sub(tape->excess_bh_size, &bh->b_count);
2623         return stage;
2624 abort:
2625         __idetape_kfree_stage(stage);
2626         return NULL;
2627 }
2628
2629 static idetape_stage_t *idetape_kmalloc_stage (idetape_tape_t *tape)
2630 {
2631         idetape_stage_t *cache_stage = tape->cache_stage;
2632
2633 #if IDETAPE_DEBUG_LOG
2634         if (tape->debug_level >= 4)
2635                 printk(KERN_INFO "ide-tape: Reached idetape_kmalloc_stage\n");
2636 #endif /* IDETAPE_DEBUG_LOG */
2637
2638         if (tape->nr_stages >= tape->max_stages)
2639                 return NULL;
2640         if (cache_stage != NULL) {
2641                 tape->cache_stage = NULL;
2642                 return cache_stage;
2643         }
2644         return __idetape_kmalloc_stage(tape, 0, 0);
2645 }
2646
2647 static int idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
2648 {
2649         struct idetape_bh *bh = tape->bh;
2650         int count;
2651         int ret = 0;
2652
2653         while (n) {
2654 #if IDETAPE_DEBUG_BUGS
2655                 if (bh == NULL) {
2656                         printk(KERN_ERR "ide-tape: bh == NULL in "
2657                                 "idetape_copy_stage_from_user\n");
2658                         return 1;
2659                 }
2660 #endif /* IDETAPE_DEBUG_BUGS */
2661                 count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), (unsigned int)n);
2662                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count))
2663                         ret = 1;
2664                 n -= count;
2665                 atomic_add(count, &bh->b_count);
2666                 buf += count;
2667                 if (atomic_read(&bh->b_count) == bh->b_size) {
2668                         bh = bh->b_reqnext;
2669                         if (bh)
2670                                 atomic_set(&bh->b_count, 0);
2671                 }
2672         }
2673         tape->bh = bh;
2674         return ret;
2675 }
2676
2677 static int idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
2678 {
2679         struct idetape_bh *bh = tape->bh;
2680         int count;
2681         int ret = 0;
2682
2683         while (n) {
2684 #if IDETAPE_DEBUG_BUGS
2685                 if (bh == NULL) {
2686                         printk(KERN_ERR "ide-tape: bh == NULL in "
2687                                 "idetape_copy_stage_to_user\n");
2688                         return 1;
2689                 }
2690 #endif /* IDETAPE_DEBUG_BUGS */
2691                 count = min(tape->b_count, n);
2692                 if  (copy_to_user(buf, tape->b_data, count))
2693                         ret = 1;
2694                 n -= count;
2695                 tape->b_data += count;
2696                 tape->b_count -= count;
2697                 buf += count;
2698                 if (!tape->b_count) {
2699                         tape->bh = bh = bh->b_reqnext;
2700                         if (bh) {
2701                                 tape->b_data = bh->b_data;
2702                                 tape->b_count = atomic_read(&bh->b_count);
2703                         }
2704                 }
2705         }
2706         return ret;
2707 }
2708
2709 static void idetape_init_merge_stage (idetape_tape_t *tape)
2710 {
2711         struct idetape_bh *bh = tape->merge_stage->bh;
2712         
2713         tape->bh = bh;
2714         if (tape->chrdev_direction == idetape_direction_write)
2715                 atomic_set(&bh->b_count, 0);
2716         else {
2717                 tape->b_data = bh->b_data;
2718                 tape->b_count = atomic_read(&bh->b_count);
2719         }
2720 }
2721
2722 static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage)
2723 {
2724         struct idetape_bh *tmp;
2725
2726         tmp = stage->bh;
2727         stage->bh = tape->merge_stage->bh;
2728         tape->merge_stage->bh = tmp;
2729         idetape_init_merge_stage(tape);
2730 }
2731
2732 /*
2733  *      idetape_add_stage_tail adds a new stage at the end of the pipeline.
2734  */
2735 static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
2736 {
2737         idetape_tape_t *tape = drive->driver_data;
2738         unsigned long flags;
2739         
2740 #if IDETAPE_DEBUG_LOG
2741         if (tape->debug_level >= 4)
2742                 printk (KERN_INFO "ide-tape: Reached idetape_add_stage_tail\n");
2743 #endif /* IDETAPE_DEBUG_LOG */
2744         spin_lock_irqsave(&tape->spinlock, flags);
2745         stage->next = NULL;
2746         if (tape->last_stage != NULL)
2747                 tape->last_stage->next=stage;
2748         else
2749                 tape->first_stage = tape->next_stage=stage;
2750         tape->last_stage = stage;
2751         if (tape->next_stage == NULL)
2752                 tape->next_stage = tape->last_stage;
2753         tape->nr_stages++;
2754         tape->nr_pending_stages++;
2755         spin_unlock_irqrestore(&tape->spinlock, flags);
2756 }
2757
2758 /*
2759  *      idetape_wait_for_request installs a completion in a pending request
2760  *      and sleeps until it is serviced.
2761  *
2762  *      The caller should ensure that the request will not be serviced
2763  *      before we install the completion (usually by disabling interrupts).
2764  */
2765 static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
2766 {
2767         DECLARE_COMPLETION(wait);
2768         idetape_tape_t *tape = drive->driver_data;
2769
2770 #if IDETAPE_DEBUG_BUGS
2771         if (rq == NULL || (rq->flags & REQ_SPECIAL) == 0) {
2772                 printk (KERN_ERR "ide-tape: bug: Trying to sleep on non-valid request\n");
2773                 return;
2774         }
2775 #endif /* IDETAPE_DEBUG_BUGS */
2776         rq->waiting = &wait;
2777         rq->end_io = blk_end_sync_rq;
2778         spin_unlock_irq(&tape->spinlock);
2779         wait_for_completion(&wait);
2780         /* The stage and its struct request have been deallocated */
2781         spin_lock_irq(&tape->spinlock);
2782 }
2783
2784 static ide_startstop_t idetape_read_position_callback (ide_drive_t *drive)
2785 {
2786         idetape_tape_t *tape = drive->driver_data;
2787         idetape_read_position_result_t *result;
2788         
2789 #if IDETAPE_DEBUG_LOG
2790         if (tape->debug_level >= 4)
2791                 printk(KERN_INFO "ide-tape: Reached idetape_read_position_callback\n");
2792 #endif /* IDETAPE_DEBUG_LOG */
2793
2794         if (!tape->pc->error) {
2795                 result = (idetape_read_position_result_t *) tape->pc->buffer;
2796 #if IDETAPE_DEBUG_LOG
2797                 if (tape->debug_level >= 2)
2798                         printk(KERN_INFO "ide-tape: BOP - %s\n",result->bop ? "Yes":"No");
2799                 if (tape->debug_level >= 2)
2800                         printk(KERN_INFO "ide-tape: EOP - %s\n",result->eop ? "Yes":"No");
2801 #endif /* IDETAPE_DEBUG_LOG */
2802                 if (result->bpu) {
2803                         printk(KERN_INFO "ide-tape: Block location is unknown to the tape\n");
2804                         clear_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2805                         idetape_end_request(drive, 0, 0);
2806                 } else {
2807 #if IDETAPE_DEBUG_LOG
2808                         if (tape->debug_level >= 2)
2809                                 printk(KERN_INFO "ide-tape: Block Location - %u\n", ntohl(result->first_block));
2810 #endif /* IDETAPE_DEBUG_LOG */
2811                         tape->partition = result->partition;
2812                         tape->first_frame_position = ntohl(result->first_block);
2813                         tape->last_frame_position = ntohl(result->last_block);
2814                         tape->blocks_in_buffer = result->blocks_in_buffer[2];
2815                         set_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2816                         idetape_end_request(drive, 1, 0);
2817                 }
2818         } else {
2819                 idetape_end_request(drive, 0, 0);
2820         }
2821         return ide_stopped;
2822 }
2823
2824 /*
2825  *      idetape_create_write_filemark_cmd will:
2826  *
2827  *              1.      Write a filemark if write_filemark=1.
2828  *              2.      Flush the device buffers without writing a filemark
2829  *                      if write_filemark=0.
2830  *
2831  */
2832 static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
2833 {
2834         idetape_init_pc(pc);
2835         pc->c[0] = IDETAPE_WRITE_FILEMARK_CMD;
2836         pc->c[4] = write_filemark;
2837         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2838         pc->callback = &idetape_pc_callback;
2839 }
2840
2841 static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
2842 {
2843         idetape_init_pc(pc);
2844         pc->c[0] = IDETAPE_TEST_UNIT_READY_CMD;
2845         pc->callback = &idetape_pc_callback;
2846 }
2847
2848 /*
2849  *      idetape_queue_pc_tail is based on the following functions:
2850  *
2851  *      ide_do_drive_cmd from ide.c
2852  *      cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c
2853  *
2854  *      We add a special packet command request to the tail of the request
2855  *      queue, and wait for it to be serviced.
2856  *
2857  *      This is not to be called from within the request handling part
2858  *      of the driver ! We allocate here data in the stack, and it is valid
2859  *      until the request is finished. This is not the case for the bottom
2860  *      part of the driver, where we are always leaving the functions to wait
2861  *      for an interrupt or a timer event.
2862  *
2863  *      From the bottom part of the driver, we should allocate safe memory
2864  *      using idetape_next_pc_storage and idetape_next_rq_storage, and add
2865  *      the request to the request list without waiting for it to be serviced !
2866  *      In that case, we usually use idetape_queue_pc_head.
2867  */
2868 static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
2869 {
2870         struct ide_tape_obj *tape = drive->driver_data;
2871         struct request rq;
2872
2873         idetape_init_rq(&rq, REQ_IDETAPE_PC1);
2874         rq.buffer = (char *) pc;
2875         rq.rq_disk = tape->disk;
2876         return ide_do_drive_cmd(drive, &rq, ide_wait);
2877 }
2878
2879 static void idetape_create_load_unload_cmd (ide_drive_t *drive, idetape_pc_t *pc,int cmd)
2880 {
2881         idetape_init_pc(pc);
2882         pc->c[0] = IDETAPE_LOAD_UNLOAD_CMD;
2883         pc->c[4] = cmd;
2884         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2885         pc->callback = &idetape_pc_callback;
2886 }
2887
2888 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
2889 {
2890         idetape_tape_t *tape = drive->driver_data;
2891         idetape_pc_t pc;
2892         int load_attempted = 0;
2893
2894         /*
2895          * Wait for the tape to become ready
2896          */
2897         set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
2898         timeout += jiffies;
2899         while (time_before(jiffies, timeout)) {
2900                 idetape_create_test_unit_ready_cmd(&pc);
2901                 if (!__idetape_queue_pc_tail(drive, &pc))
2902                         return 0;
2903                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
2904                     || (tape->asc == 0x3A)) {   /* no media */
2905                         if (load_attempted)
2906                                 return -ENOMEDIUM;
2907                         idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
2908                         __idetape_queue_pc_tail(drive, &pc);
2909                         load_attempted = 1;
2910                 /* not about to be ready */
2911                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
2912                              (tape->ascq == 1 || tape->ascq == 8)))
2913                         return -EIO;
2914                 msleep(100);
2915         }
2916         return -EIO;
2917 }
2918
2919 static int idetape_queue_pc_tail (ide_drive_t *drive,idetape_pc_t *pc)
2920 {
2921         return __idetape_queue_pc_tail(drive, pc);
2922 }
2923
2924 static int idetape_flush_tape_buffers (ide_drive_t *drive)
2925 {
2926         idetape_pc_t pc;
2927         int rc;
2928
2929         idetape_create_write_filemark_cmd(drive, &pc, 0);
2930         if ((rc = idetape_queue_pc_tail(drive, &pc)))
2931                 return rc;
2932         idetape_wait_ready(drive, 60 * 5 * HZ);
2933         return 0;
2934 }
2935
2936 static void idetape_create_read_position_cmd (idetape_pc_t *pc)
2937 {
2938         idetape_init_pc(pc);
2939         pc->c[0] = IDETAPE_READ_POSITION_CMD;
2940         pc->request_transfer = 20;
2941         pc->callback = &idetape_read_position_callback;
2942 }
2943
2944 static int idetape_read_position (ide_drive_t *drive)
2945 {
2946         idetape_tape_t *tape = drive->driver_data;
2947         idetape_pc_t pc;
2948         int position;
2949
2950 #if IDETAPE_DEBUG_LOG
2951         if (tape->debug_level >= 4)
2952                 printk(KERN_INFO "ide-tape: Reached idetape_read_position\n");
2953 #endif /* IDETAPE_DEBUG_LOG */
2954
2955         idetape_create_read_position_cmd(&pc);
2956         if (idetape_queue_pc_tail(drive, &pc))
2957                 return -1;
2958         position = tape->first_frame_position;
2959         return position;
2960 }
2961
2962 static void idetape_create_locate_cmd (ide_drive_t *drive, idetape_pc_t *pc, unsigned int block, u8 partition, int skip)
2963 {
2964         idetape_init_pc(pc);
2965         pc->c[0] = IDETAPE_LOCATE_CMD;
2966         pc->c[1] = 2;
2967         put_unaligned(htonl(block), (unsigned int *) &pc->c[3]);
2968         pc->c[8] = partition;
2969         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2970         pc->callback = &idetape_pc_callback;
2971 }
2972
2973 static int idetape_create_prevent_cmd (ide_drive_t *drive, idetape_pc_t *pc, int prevent)
2974 {
2975         idetape_tape_t *tape = drive->driver_data;
2976
2977         if (!tape->capabilities.lock)
2978                 return 0;
2979
2980         idetape_init_pc(pc);
2981         pc->c[0] = IDETAPE_PREVENT_CMD;
2982         pc->c[4] = prevent;
2983         pc->callback = &idetape_pc_callback;
2984         return 1;
2985 }
2986
2987 static int __idetape_discard_read_pipeline (ide_drive_t *drive)
2988 {
2989         idetape_tape_t *tape = drive->driver_data;
2990         unsigned long flags;
2991         int cnt;
2992
2993         if (tape->chrdev_direction != idetape_direction_read)
2994                 return 0;
2995
2996         /* Remove merge stage. */
2997         cnt = tape->merge_stage_size / tape->tape_block_size;
2998         if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
2999                 ++cnt;          /* Filemarks count as 1 sector */
3000         tape->merge_stage_size = 0;
3001         if (tape->merge_stage != NULL) {
3002                 __idetape_kfree_stage(tape->merge_stage);
3003                 tape->merge_stage = NULL;
3004         }
3005
3006         /* Clear pipeline flags. */
3007         clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3008         tape->chrdev_direction = idetape_direction_none;
3009
3010         /* Remove pipeline stages. */
3011         if (tape->first_stage == NULL)
3012                 return 0;
3013
3014         spin_lock_irqsave(&tape->spinlock, flags);
3015         tape->next_stage = NULL;
3016         if (idetape_pipeline_active(tape))
3017                 idetape_wait_for_request(drive, tape->active_data_request);
3018         spin_unlock_irqrestore(&tape->spinlock, flags);
3019
3020         while (tape->first_stage != NULL) {
3021                 struct request *rq_ptr = &tape->first_stage->rq;
3022
3023                 cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors; 
3024                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3025                         ++cnt;
3026                 idetape_remove_stage_head(drive);
3027         }
3028         tape->nr_pending_stages = 0;
3029         tape->max_stages = tape->min_pipeline;
3030         return cnt;
3031 }
3032
3033 /*
3034  *      idetape_position_tape positions the tape to the requested block
3035  *      using the LOCATE packet command. A READ POSITION command is then
3036  *      issued to check where we are positioned.
3037  *
3038  *      Like all higher level operations, we queue the commands at the tail
3039  *      of the request queue and wait for their completion.
3040  *      
3041  */
3042 static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
3043 {
3044         idetape_tape_t *tape = drive->driver_data;
3045         int retval;
3046         idetape_pc_t pc;
3047
3048         if (tape->chrdev_direction == idetape_direction_read)
3049                 __idetape_discard_read_pipeline(drive);
3050         idetape_wait_ready(drive, 60 * 5 * HZ);
3051         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
3052         retval = idetape_queue_pc_tail(drive, &pc);
3053         if (retval)
3054                 return (retval);
3055
3056         idetape_create_read_position_cmd(&pc);
3057         return (idetape_queue_pc_tail(drive, &pc));
3058 }
3059
3060 static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_position)
3061 {
3062         idetape_tape_t *tape = drive->driver_data;
3063         int cnt;
3064         int seek, position;
3065
3066         cnt = __idetape_discard_read_pipeline(drive);
3067         if (restore_position) {
3068                 position = idetape_read_position(drive);
3069                 seek = position > cnt ? position - cnt : 0;
3070                 if (idetape_position_tape(drive, seek, 0, 0)) {
3071                         printk(KERN_INFO "ide-tape: %s: position_tape failed in discard_pipeline()\n", tape->name);
3072                         return;
3073                 }
3074         }
3075 }
3076
3077 /*
3078  * idetape_queue_rw_tail generates a read/write request for the block
3079  * device interface and wait for it to be serviced.
3080  */
3081 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
3082 {
3083         idetape_tape_t *tape = drive->driver_data;
3084         struct request rq;
3085
3086 #if IDETAPE_DEBUG_LOG
3087         if (tape->debug_level >= 2)
3088                 printk(KERN_INFO "ide-tape: idetape_queue_rw_tail: cmd=%d\n",cmd);
3089 #endif /* IDETAPE_DEBUG_LOG */
3090 #if IDETAPE_DEBUG_BUGS
3091         if (idetape_pipeline_active(tape)) {
3092                 printk(KERN_ERR "ide-tape: bug: the pipeline is active in idetape_queue_rw_tail\n");
3093                 return (0);
3094         }
3095 #endif /* IDETAPE_DEBUG_BUGS */ 
3096
3097         idetape_init_rq(&rq, cmd);
3098         rq.rq_disk = tape->disk;
3099         rq.special = (void *)bh;
3100         rq.sector = tape->first_frame_position;
3101         rq.nr_sectors = rq.current_nr_sectors = blocks;
3102         (void) ide_do_drive_cmd(drive, &rq, ide_wait);
3103
3104         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
3105                 return 0;
3106
3107         if (tape->merge_stage)
3108                 idetape_init_merge_stage(tape);
3109         if (rq.errors == IDETAPE_ERROR_GENERAL)
3110                 return -EIO;
3111         return (tape->tape_block_size * (blocks-rq.current_nr_sectors));
3112 }
3113
3114 /*
3115  *      idetape_insert_pipeline_into_queue is used to start servicing the
3116  *      pipeline stages, starting from tape->next_stage.
3117  */
3118 static void idetape_insert_pipeline_into_queue (ide_drive_t *drive)
3119 {
3120         idetape_tape_t *tape = drive->driver_data;
3121
3122         if (tape->next_stage == NULL)
3123                 return;
3124         if (!idetape_pipeline_active(tape)) {
3125                 set_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
3126                 idetape_active_next_stage(drive);
3127                 (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
3128         }
3129 }
3130
3131 static void idetape_create_inquiry_cmd (idetape_pc_t *pc)
3132 {
3133         idetape_init_pc(pc);
3134         pc->c[0] = IDETAPE_INQUIRY_CMD;
3135         pc->c[4] = pc->request_transfer = 254;
3136         pc->callback = &idetape_pc_callback;
3137 }
3138
3139 static void idetape_create_rewind_cmd (ide_drive_t *drive, idetape_pc_t *pc)
3140 {
3141         idetape_init_pc(pc);
3142         pc->c[0] = IDETAPE_REWIND_CMD;
3143         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3144         pc->callback = &idetape_pc_callback;
3145 }
3146
3147 #if 0
3148 static void idetape_create_mode_select_cmd (idetape_pc_t *pc, int length)
3149 {
3150         idetape_init_pc(pc);
3151         set_bit(PC_WRITING, &pc->flags);
3152         pc->c[0] = IDETAPE_MODE_SELECT_CMD;
3153         pc->c[1] = 0x10;
3154         put_unaligned(htons(length), (unsigned short *) &pc->c[3]);
3155         pc->request_transfer = 255;
3156         pc->callback = &idetape_pc_callback;
3157 }
3158 #endif
3159
3160 static void idetape_create_erase_cmd (idetape_pc_t *pc)
3161 {
3162         idetape_init_pc(pc);
3163         pc->c[0] = IDETAPE_ERASE_CMD;
3164         pc->c[1] = 1;
3165         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3166         pc->callback = &idetape_pc_callback;
3167 }
3168
3169 static void idetape_create_space_cmd (idetape_pc_t *pc,int count, u8 cmd)
3170 {
3171         idetape_init_pc(pc);
3172         pc->c[0] = IDETAPE_SPACE_CMD;
3173         put_unaligned(htonl(count), (unsigned int *) &pc->c[1]);
3174         pc->c[1] = cmd;
3175         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3176         pc->callback = &idetape_pc_callback;
3177 }
3178
3179 static void idetape_wait_first_stage (ide_drive_t *drive)
3180 {
3181         idetape_tape_t *tape = drive->driver_data;
3182         unsigned long flags;
3183
3184         if (tape->first_stage == NULL)
3185                 return;
3186         spin_lock_irqsave(&tape->spinlock, flags);
3187         if (tape->active_stage == tape->first_stage)
3188                 idetape_wait_for_request(drive, tape->active_data_request);
3189         spin_unlock_irqrestore(&tape->spinlock, flags);
3190 }
3191
3192 /*
3193  *      idetape_add_chrdev_write_request tries to add a character device
3194  *      originated write request to our pipeline. In case we don't succeed,
3195  *      we revert to non-pipelined operation mode for this request.
3196  *
3197  *      1.      Try to allocate a new pipeline stage.
3198  *      2.      If we can't, wait for more and more requests to be serviced
3199  *              and try again each time.
3200  *      3.      If we still can't allocate a stage, fallback to
3201  *              non-pipelined operation mode for this request.
3202  */
3203 static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
3204 {
3205         idetape_tape_t *tape = drive->driver_data;
3206         idetape_stage_t *new_stage;
3207         unsigned long flags;
3208         struct request *rq;
3209
3210 #if IDETAPE_DEBUG_LOG
3211         if (tape->debug_level >= 3)
3212                 printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_write_request\n");
3213 #endif /* IDETAPE_DEBUG_LOG */
3214
3215         /*
3216          *      Attempt to allocate a new stage.
3217          *      Pay special attention to possible race conditions.
3218          */
3219         while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
3220                 spin_lock_irqsave(&tape->spinlock, flags);
3221                 if (idetape_pipeline_active(tape)) {
3222                         idetape_wait_for_request(drive, tape->active_data_request);
3223                         spin_unlock_irqrestore(&tape->spinlock, flags);
3224                 } else {
3225                         spin_unlock_irqrestore(&tape->spinlock, flags);
3226                         idetape_insert_pipeline_into_queue(drive);
3227                         if (idetape_pipeline_active(tape))
3228                                 continue;
3229                         /*
3230                          *      Linux is short on memory. Fallback to
3231                          *      non-pipelined operation mode for this request.
3232                          */
3233                         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3234                 }
3235         }
3236         rq = &new_stage->rq;
3237         idetape_init_rq(rq, REQ_IDETAPE_WRITE);
3238         /* Doesn't actually matter - We always assume sequential access */
3239         rq->sector = tape->first_frame_position;
3240         rq->nr_sectors = rq->current_nr_sectors = blocks;
3241
3242         idetape_switch_buffers(tape, new_stage);
3243         idetape_add_stage_tail(drive, new_stage);
3244         tape->pipeline_head++;
3245 #if USE_IOTRACE
3246         IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
3247 #endif
3248         calculate_speeds(drive);
3249
3250         /*
3251          *      Estimate whether the tape has stopped writing by checking
3252          *      if our write pipeline is currently empty. If we are not
3253          *      writing anymore, wait for the pipeline to be full enough
3254          *      (90%) before starting to service requests, so that we will
3255          *      be able to keep up with the higher speeds of the tape.
3256          */
3257         if (!idetape_pipeline_active(tape)) {
3258                 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
3259                     tape->nr_stages >= tape->max_stages - tape->uncontrolled_pipeline_head_speed * 3 * 1024 / tape->tape_block_size) {
3260                         tape->measure_insert_time = 1;
3261                         tape->insert_time = jiffies;
3262                         tape->insert_size = 0;
3263                         tape->insert_speed = 0;
3264                         idetape_insert_pipeline_into_queue(drive);
3265                 }
3266         }
3267         if (test_and_clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3268                 /* Return a deferred error */
3269                 return -EIO;
3270         return blocks;
3271 }
3272
3273 /*
3274  *      idetape_wait_for_pipeline will wait until all pending pipeline
3275  *      requests are serviced. Typically called on device close.
3276  */
3277 static void idetape_wait_for_pipeline (ide_drive_t *drive)
3278 {
3279         idetape_tape_t *tape = drive->driver_data;
3280         unsigned long flags;
3281
3282         while (tape->next_stage || idetape_pipeline_active(tape)) {
3283                 idetape_insert_pipeline_into_queue(drive);
3284                 spin_lock_irqsave(&tape->spinlock, flags);
3285                 if (idetape_pipeline_active(tape))
3286                         idetape_wait_for_request(drive, tape->active_data_request);
3287                 spin_unlock_irqrestore(&tape->spinlock, flags);
3288         }
3289 }
3290
3291 static void idetape_empty_write_pipeline (ide_drive_t *drive)
3292 {
3293         idetape_tape_t *tape = drive->driver_data;
3294         int blocks, min;
3295         struct idetape_bh *bh;
3296         
3297 #if IDETAPE_DEBUG_BUGS
3298         if (tape->chrdev_direction != idetape_direction_write) {
3299                 printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline, but we are not writing.\n");
3300                 return;
3301         }
3302         if (tape->merge_stage_size > tape->stage_size) {
3303                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
3304                 tape->merge_stage_size = tape->stage_size;
3305         }
3306 #endif /* IDETAPE_DEBUG_BUGS */
3307         if (tape->merge_stage_size) {
3308                 blocks = tape->merge_stage_size / tape->tape_block_size;
3309                 if (tape->merge_stage_size % tape->tape_block_size) {
3310                         unsigned int i;
3311
3312                         blocks++;
3313                         i = tape->tape_block_size - tape->merge_stage_size % tape->tape_block_size;
3314                         bh = tape->bh->b_reqnext;
3315                         while (bh) {
3316                                 atomic_set(&bh->b_count, 0);
3317                                 bh = bh->b_reqnext;
3318                         }
3319                         bh = tape->bh;
3320                         while (i) {
3321                                 if (bh == NULL) {
3322
3323                                         printk(KERN_INFO "ide-tape: bug, bh NULL\n");
3324                                         break;
3325                                 }
3326                                 min = min(i, (unsigned int)(bh->b_size - atomic_read(&bh->b_count)));
3327                                 memset(bh->b_data + atomic_read(&bh->b_count), 0, min);
3328                                 atomic_add(min, &bh->b_count);
3329                                 i -= min;
3330                                 bh = bh->b_reqnext;
3331                         }
3332                 }
3333                 (void) idetape_add_chrdev_write_request(drive, blocks);
3334                 tape->merge_stage_size = 0;
3335         }
3336         idetape_wait_for_pipeline(drive);
3337         if (tape->merge_stage != NULL) {
3338                 __idetape_kfree_stage(tape->merge_stage);
3339                 tape->merge_stage = NULL;
3340         }
3341         clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3342         tape->chrdev_direction = idetape_direction_none;
3343
3344         /*
3345          *      On the next backup, perform the feedback loop again.
3346          *      (I don't want to keep sense information between backups,
3347          *       as some systems are constantly on, and the system load
3348          *       can be totally different on the next backup).
3349          */
3350         tape->max_stages = tape->min_pipeline;
3351 #if IDETAPE_DEBUG_BUGS
3352         if (tape->first_stage != NULL ||
3353             tape->next_stage != NULL ||
3354             tape->last_stage != NULL ||
3355             tape->nr_stages != 0) {
3356                 printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
3357                         "first_stage %p, next_stage %p, "
3358                         "last_stage %p, nr_stages %d\n",
3359                         tape->first_stage, tape->next_stage,
3360                         tape->last_stage, tape->nr_stages);
3361         }
3362 #endif /* IDETAPE_DEBUG_BUGS */
3363 }
3364
3365 static void idetape_restart_speed_control (ide_drive_t *drive)
3366 {
3367         idetape_tape_t *tape = drive->driver_data;
3368
3369         tape->restart_speed_control_req = 0;
3370         tape->pipeline_head = 0;
3371         tape->controlled_last_pipeline_head = tape->uncontrolled_last_pipeline_head = 0;
3372         tape->controlled_previous_pipeline_head = tape->uncontrolled_previous_pipeline_head = 0;
3373         tape->pipeline_head_speed = tape->controlled_pipeline_head_speed = 5000;
3374         tape->uncontrolled_pipeline_head_speed = 0;
3375         tape->controlled_pipeline_head_time = tape->uncontrolled_pipeline_head_time = jiffies;
3376         tape->controlled_previous_head_time = tape->uncontrolled_previous_head_time = jiffies;
3377 }
3378
3379 static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
3380 {
3381         idetape_tape_t *tape = drive->driver_data;
3382         idetape_stage_t *new_stage;
3383         struct request rq;
3384         int bytes_read;
3385         int blocks = tape->capabilities.ctl;
3386
3387         /* Initialize read operation */
3388         if (tape->chrdev_direction != idetape_direction_read) {
3389                 if (tape->chrdev_direction == idetape_direction_write) {
3390                         idetape_empty_write_pipeline(drive);
3391                         idetape_flush_tape_buffers(drive);
3392                 }
3393 #if IDETAPE_DEBUG_BUGS
3394                 if (tape->merge_stage || tape->merge_stage_size) {
3395                         printk (KERN_ERR "ide-tape: merge_stage_size should be 0 now\n");
3396                         tape->merge_stage_size = 0;
3397                 }
3398 #endif /* IDETAPE_DEBUG_BUGS */
3399                 if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3400                         return -ENOMEM;
3401                 tape->chrdev_direction = idetape_direction_read;
3402
3403                 /*
3404                  *      Issue a read 0 command to ensure that DSC handshake
3405                  *      is switched from completion mode to buffer available
3406                  *      mode.
3407                  *      No point in issuing this if DSC overlap isn't supported,
3408                  *      some drives (Seagate STT3401A) will return an error.
3409                  */
3410                 if (drive->dsc_overlap) {
3411                         bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
3412                         if (bytes_read < 0) {
3413                                 __idetape_kfree_stage(tape->merge_stage);
3414                                 tape->merge_stage = NULL;
3415                                 tape->chrdev_direction = idetape_direction_none;
3416                                 return bytes_read;
3417                         }
3418                 }
3419         }
3420         if (tape->restart_speed_control_req)
3421                 idetape_restart_speed_control(drive);
3422         idetape_init_rq(&rq, REQ_IDETAPE_READ);
3423         rq.sector = tape->first_frame_position;
3424         rq.nr_sectors = rq.current_nr_sectors = blocks;
3425         if (!test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags) &&
3426             tape->nr_stages < max_stages) {
3427                 new_stage = idetape_kmalloc_stage(tape);
3428                 while (new_stage != NULL) {
3429                         new_stage->rq = rq;
3430                         idetape_add_stage_tail(drive, new_stage);
3431                         if (tape->nr_stages >= max_stages)
3432                                 break;
3433                         new_stage = idetape_kmalloc_stage(tape);
3434                 }
3435         }
3436         if (!idetape_pipeline_active(tape)) {
3437                 if (tape->nr_pending_stages >= 3 * max_stages / 4) {
3438                         tape->measure_insert_time = 1;
3439                         tape->insert_time = jiffies;
3440                         tape->insert_size = 0;
3441                         tape->insert_speed = 0;
3442                         idetape_insert_pipeline_into_queue(drive);
3443                 }
3444         }
3445         return 0;
3446 }
3447
3448 /*
3449  *      idetape_add_chrdev_read_request is called from idetape_chrdev_read
3450  *      to service a character device read request and add read-ahead
3451  *      requests to our pipeline.
3452  */
3453 static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
3454 {
3455         idetape_tape_t *tape = drive->driver_data;
3456         unsigned long flags;
3457         struct request *rq_ptr;
3458         int bytes_read;
3459
3460 #if IDETAPE_DEBUG_LOG
3461         if (tape->debug_level >= 4)
3462                 printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_read_request, %d blocks\n", blocks);
3463 #endif /* IDETAPE_DEBUG_LOG */
3464
3465         /*
3466          * If we are at a filemark, return a read length of 0
3467          */
3468         if (test_bit(IDETAPE_FILEMARK, &tape->flags))
3469                 return 0;
3470
3471         /*
3472          * Wait for the next block to be available at the head
3473          * of the pipeline
3474          */
3475         idetape_initiate_read(drive, tape->max_stages);
3476         if (tape->first_stage == NULL) {
3477                 if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3478                         return 0;
3479                 return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, tape->merge_stage->bh);
3480         }
3481         idetape_wait_first_stage(drive);
3482         rq_ptr = &tape->first_stage->rq;
3483         bytes_read = tape->tape_block_size * (rq_ptr->nr_sectors - rq_ptr->current_nr_sectors);
3484         rq_ptr->nr_sectors = rq_ptr->current_nr_sectors = 0;
3485
3486
3487         if (rq_ptr->errors == IDETAPE_ERROR_EOD)
3488                 return 0;
3489         else {
3490                 idetape_switch_buffers(tape, tape->first_stage);
3491                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3492                         set_bit(IDETAPE_FILEMARK, &tape->flags);
3493                 spin_lock_irqsave(&tape->spinlock, flags);
3494                 idetape_remove_stage_head(drive);
3495                 spin_unlock_irqrestore(&tape->spinlock, flags);
3496                 tape->pipeline_head++;
3497 #if USE_IOTRACE
3498                 IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
3499 #endif
3500                 calculate_speeds(drive);
3501         }
3502 #if IDETAPE_DEBUG_BUGS
3503         if (bytes_read > blocks * tape->tape_block_size) {
3504                 printk(KERN_ERR "ide-tape: bug: trying to return more bytes than requested\n");
3505                 bytes_read = blocks * tape->tape_block_size;
3506         }
3507 #endif /* IDETAPE_DEBUG_BUGS */
3508         return (bytes_read);
3509 }
3510
3511 static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
3512 {
3513         idetape_tape_t *tape = drive->driver_data;
3514         struct idetape_bh *bh;
3515         int blocks;
3516         
3517         while (bcount) {
3518                 unsigned int count;
3519
3520                 bh = tape->merge_stage->bh;
3521                 count = min(tape->stage_size, bcount);
3522                 bcount -= count;
3523                 blocks = count / tape->tape_block_size;
3524                 while (count) {
3525                         atomic_set(&bh->b_count, min(count, (unsigned int)bh->b_size));
3526                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
3527                         count -= atomic_read(&bh->b_count);
3528                         bh = bh->b_reqnext;
3529                 }
3530                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3531         }
3532 }
3533
3534 static int idetape_pipeline_size (ide_drive_t *drive)
3535 {
3536         idetape_tape_t *tape = drive->driver_data;
3537         idetape_stage_t *stage;
3538         struct request *rq;
3539         int size = 0;
3540
3541         idetape_wait_for_pipeline(drive);
3542         stage = tape->first_stage;
3543         while (stage != NULL) {
3544                 rq = &stage->rq;
3545                 size += tape->tape_block_size * (rq->nr_sectors-rq->current_nr_sectors);
3546                 if (rq->errors == IDETAPE_ERROR_FILEMARK)
3547                         size += tape->tape_block_size;
3548                 stage = stage->next;
3549         }
3550         size += tape->merge_stage_size;
3551         return size;
3552 }
3553
3554 /*
3555  *      Rewinds the tape to the Beginning Of the current Partition (BOP).
3556  *
3557  *      We currently support only one partition.
3558  */ 
3559 static int idetape_rewind_tape (ide_drive_t *drive)
3560 {
3561         int retval;
3562         idetape_pc_t pc;
3563 #if IDETAPE_DEBUG_LOG
3564         idetape_tape_t *tape = drive->driver_data;
3565         if (tape->debug_level >= 2)
3566                 printk(KERN_INFO "ide-tape: Reached idetape_rewind_tape\n");
3567 #endif /* IDETAPE_DEBUG_LOG */  
3568         
3569         idetape_create_rewind_cmd(drive, &pc);
3570         retval = idetape_queue_pc_tail(drive, &pc);
3571         if (retval)
3572                 return retval;
3573
3574         idetape_create_read_position_cmd(&pc);
3575         retval = idetape_queue_pc_tail(drive, &pc);
3576         if (retval)
3577                 return retval;
3578         return 0;
3579 }
3580
3581 /*
3582  *      Our special ide-tape ioctl's.
3583  *
3584  *      Currently there aren't any ioctl's.
3585  *      mtio.h compatible commands should be issued to the character device
3586  *      interface.
3587  */
3588 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
3589 {
3590         idetape_tape_t *tape = drive->driver_data;
3591         idetape_config_t config;
3592         void __user *argp = (void __user *)arg;
3593
3594 #if IDETAPE_DEBUG_LOG   
3595         if (tape->debug_level >= 4)
3596                 printk(KERN_INFO "ide-tape: Reached idetape_blkdev_ioctl\n");
3597 #endif /* IDETAPE_DEBUG_LOG */
3598         switch (cmd) {
3599                 case 0x0340:
3600                         if (copy_from_user(&config, argp, sizeof (idetape_config_t)))
3601                                 return -EFAULT;
3602                         tape->best_dsc_rw_frequency = config.dsc_rw_frequency;
3603                         tape->max_stages = config.nr_stages;
3604                         break;
3605                 case 0x0350:
3606                         config.dsc_rw_frequency = (int) tape->best_dsc_rw_frequency;
3607                         config.nr_stages = tape->max_stages; 
3608                         if (copy_to_user(argp, &config, sizeof (idetape_config_t)))
3609                                 return -EFAULT;
3610                         break;
3611                 default:
3612                         return -EIO;
3613         }
3614         return 0;
3615 }
3616
3617 /*
3618  *      idetape_space_over_filemarks is now a bit more complicated than just
3619  *      passing the command to the tape since we may have crossed some
3620  *      filemarks during our pipelined read-ahead mode.
3621  *
3622  *      As a minor side effect, the pipeline enables us to support MTFSFM when
3623  *      the filemark is in our internal pipeline even if the tape doesn't
3624  *      support spacing over filemarks in the reverse direction.
3625  */
3626 static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
3627 {
3628         idetape_tape_t *tape = drive->driver_data;
3629         idetape_pc_t pc;
3630         unsigned long flags;
3631         int retval,count=0;
3632
3633         if (mt_count == 0)
3634                 return 0;
3635         if (MTBSF == mt_op || MTBSFM == mt_op) {
3636                 if (!tape->capabilities.sprev)
3637                         return -EIO;
3638                 mt_count = - mt_count;
3639         }
3640
3641         if (tape->chrdev_direction == idetape_direction_read) {
3642                 /*
3643                  *      We have a read-ahead buffer. Scan it for crossed
3644                  *      filemarks.
3645                  */
3646                 tape->merge_stage_size = 0;
3647                 if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
3648                         ++count;
3649                 while (tape->first_stage != NULL) {
3650                         if (count == mt_count) {
3651                                 if (mt_op == MTFSFM)
3652                                         set_bit(IDETAPE_FILEMARK, &tape->flags);
3653                                 return 0;
3654                         }
3655                         spin_lock_irqsave(&tape->spinlock, flags);
3656                         if (tape->first_stage == tape->active_stage) {
3657                                 /*
3658                                  *      We have reached the active stage in the read pipeline.
3659                                  *      There is no point in allowing the drive to continue
3660                                  *      reading any farther, so we stop the pipeline.
3661                                  *
3662                                  *      This section should be moved to a separate subroutine,
3663                                  *      because a similar function is performed in
3664                                  *      __idetape_discard_read_pipeline(), for example.
3665                                  */
3666                                 tape->next_stage = NULL;
3667                                 spin_unlock_irqrestore(&tape->spinlock, flags);
3668                                 idetape_wait_first_stage(drive);
3669                                 tape->next_stage = tape->first_stage->next;
3670                         } else
3671                                 spin_unlock_irqrestore(&tape->spinlock, flags);
3672                         if (tape->first_stage->rq.errors == IDETAPE_ERROR_FILEMARK)
3673                                 ++count;
3674                         idetape_remove_stage_head(drive);
3675                 }
3676                 idetape_discard_read_pipeline(drive, 0);
3677         }
3678
3679         /*
3680          *      The filemark was not found in our internal pipeline.
3681          *      Now we can issue the space command.
3682          */
3683         switch (mt_op) {
3684                 case MTFSF:
3685                 case MTBSF:
3686                         idetape_create_space_cmd(&pc,mt_count-count,IDETAPE_SPACE_OVER_FILEMARK);
3687                         return (idetape_queue_pc_tail(drive, &pc));
3688                 case MTFSFM:
3689                 case MTBSFM:
3690                         if (!tape->capabilities.sprev)
3691                                 return (-EIO);
3692                         retval = idetape_space_over_filemarks(drive, MTFSF, mt_count-count);
3693                         if (retval) return (retval);
3694                         count = (MTBSFM == mt_op ? 1 : -1);
3695                         return (idetape_space_over_filemarks(drive, MTFSF, count));
3696                 default:
3697                         printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",mt_op);
3698                         return (-EIO);
3699         }
3700 }
3701
3702
3703 /*
3704  *      Our character device read / write functions.
3705  *
3706  *      The tape is optimized to maximize throughput when it is transferring
3707  *      an integral number of the "continuous transfer limit", which is
3708  *      a parameter of the specific tape (26 KB on my particular tape).
3709  *      (32 kB for Onstream)
3710  *
3711  *      As of version 1.3 of the driver, the character device provides an
3712  *      abstract continuous view of the media - any mix of block sizes (even 1
3713  *      byte) on the same backup/restore procedure is supported. The driver
3714  *      will internally convert the requests to the recommended transfer unit,
3715  *      so that an unmatch between the user's block size to the recommended
3716  *      size will only result in a (slightly) increased driver overhead, but
3717  *      will no longer hit performance.
3718  *      This is not applicable to Onstream.
3719  */
3720 static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
3721                                     size_t count, loff_t *ppos)
3722 {
3723         struct ide_tape_obj *tape = ide_tape_f(file);
3724         ide_drive_t *drive = tape->drive;
3725         ssize_t bytes_read,temp, actually_read = 0, rc;
3726         ssize_t ret = 0;
3727
3728 #if IDETAPE_DEBUG_LOG
3729         if (tape->debug_level >= 3)
3730                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_read, count %Zd\n", count);
3731 #endif /* IDETAPE_DEBUG_LOG */
3732
3733         if (tape->chrdev_direction != idetape_direction_read) {
3734                 if (test_bit(IDETAPE_DETECT_BS, &tape->flags))
3735                         if (count > tape->tape_block_size &&
3736                             (count % tape->tape_block_size) == 0)
3737                                 tape->user_bs_factor = count / tape->tape_block_size;
3738         }
3739         if ((rc = idetape_initiate_read(drive, tape->max_stages)) < 0)
3740                 return rc;
3741         if (count == 0)
3742                 return (0);
3743         if (tape->merge_stage_size) {
3744                 actually_read = min((unsigned int)(tape->merge_stage_size), (unsigned int)count);
3745                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read))
3746                         ret = -EFAULT;
3747                 buf += actually_read;
3748                 tape->merge_stage_size -= actually_read;
3749                 count -= actually_read;
3750         }
3751         while (count >= tape->stage_size) {
3752                 bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3753                 if (bytes_read <= 0)
3754                         goto finish;
3755                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read))
3756                         ret = -EFAULT;
3757                 buf += bytes_read;
3758                 count -= bytes_read;
3759                 actually_read += bytes_read;
3760         }
3761         if (count) {
3762                 bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3763                 if (bytes_read <= 0)
3764                         goto finish;
3765                 temp = min((unsigned long)count, (unsigned long)bytes_read);
3766                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp))
3767                         ret = -EFAULT;
3768                 actually_read += temp;
3769                 tape->merge_stage_size = bytes_read-temp;
3770         }
3771 finish:
3772         if (!actually_read && test_bit(IDETAPE_FILEMARK, &tape->flags)) {
3773 #if IDETAPE_DEBUG_LOG
3774                 if (tape->debug_level >= 2)
3775                         printk(KERN_INFO "ide-tape: %s: spacing over filemark\n", tape->name);
3776 #endif
3777                 idetape_space_over_filemarks(drive, MTFSF, 1);
3778                 return 0;
3779         }
3780
3781         return (ret) ? ret : actually_read;
3782 }
3783
3784 static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
3785                                      size_t count, loff_t *ppos)
3786 {
3787         struct ide_tape_obj *tape = ide_tape_f(file);
3788         ide_drive_t *drive = tape->drive;
3789         ssize_t actually_written = 0;
3790         ssize_t ret = 0;
3791
3792         /* The drive is write protected. */
3793         if (tape->write_prot)
3794                 return -EACCES;
3795
3796 #if IDETAPE_DEBUG_LOG
3797         if (tape->debug_level >= 3)
3798                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_write, "
3799                         "count %Zd\n", count);
3800 #endif /* IDETAPE_DEBUG_LOG */
3801
3802         /* Initialize write operation */
3803         if (tape->chrdev_direction != idetape_direction_write) {
3804                 if (tape->chrdev_direction == idetape_direction_read)
3805                         idetape_discard_read_pipeline(drive, 1);
3806 #if IDETAPE_DEBUG_BUGS
3807                 if (tape->merge_stage || tape->merge_stage_size) {
3808                         printk(KERN_ERR "ide-tape: merge_stage_size "
3809                                 "should be 0 now\n");
3810                         tape->merge_stage_size = 0;
3811                 }
3812 #endif /* IDETAPE_DEBUG_BUGS */
3813                 if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3814                         return -ENOMEM;
3815                 tape->chrdev_direction = idetape_direction_write;
3816                 idetape_init_merge_stage(tape);
3817
3818                 /*
3819                  *      Issue a write 0 command to ensure that DSC handshake
3820                  *      is switched from completion mode to buffer available
3821                  *      mode.
3822                  *      No point in issuing this if DSC overlap isn't supported,
3823                  *      some drives (Seagate STT3401A) will return an error.
3824                  */
3825                 if (drive->dsc_overlap) {
3826                         ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
3827                         if (retval < 0) {
3828                                 __idetape_kfree_stage(tape->merge_stage);
3829                                 tape->merge_stage = NULL;
3830                                 tape->chrdev_direction = idetape_direction_none;
3831                                 return retval;
3832                         }
3833                 }
3834         }
3835         if (count == 0)
3836                 return (0);
3837         if (tape->restart_speed_control_req)
3838                 idetape_restart_speed_control(drive);
3839         if (tape->merge_stage_size) {
3840 #if IDETAPE_DEBUG_BUGS
3841                 if (tape->merge_stage_size >= tape->stage_size) {
3842                         printk(KERN_ERR "ide-tape: bug: merge buffer too big\n");
3843                         tape->merge_stage_size = 0;
3844                 }
3845 #endif /* IDETAPE_DEBUG_BUGS */
3846                 actually_written = min((unsigned int)(tape->stage_size - tape->merge_stage_size), (unsigned int)count);
3847                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written))
3848                                 ret = -EFAULT;
3849                 buf += actually_written;
3850                 tape->merge_stage_size += actually_written;
3851                 count -= actually_written;
3852
3853                 if (tape->merge_stage_size == tape->stage_size) {
3854                         ssize_t retval;
3855                         tape->merge_stage_size = 0;
3856                         retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3857                         if (retval <= 0)
3858                                 return (retval);
3859                 }
3860         }
3861         while (count >= tape->stage_size) {
3862                 ssize_t retval;
3863                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size))
3864                         ret = -EFAULT;
3865                 buf += tape->stage_size;
3866                 count -= tape->stage_size;
3867                 retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3868                 actually_written += tape->stage_size;
3869                 if (retval <= 0)
3870                         return (retval);
3871         }
3872         if (count) {
3873                 actually_written += count;
3874                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count))
3875                         ret = -EFAULT;
3876                 tape->merge_stage_size += count;
3877         }
3878         return (ret) ? ret : actually_written;
3879 }
3880
3881 static int idetape_write_filemark (ide_drive_t *drive)
3882 {
3883         idetape_pc_t pc;
3884
3885         /* Write a filemark */
3886         idetape_create_write_filemark_cmd(drive, &pc, 1);
3887         if (idetape_queue_pc_tail(drive, &pc)) {
3888                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
3889                 return -EIO;
3890         }
3891         return 0;
3892 }
3893
3894 /*
3895  *      idetape_mtioctop is called from idetape_chrdev_ioctl when
3896  *      the general mtio MTIOCTOP ioctl is requested.
3897  *
3898  *      We currently support the following mtio.h operations:
3899  *
3900  *      MTFSF   -       Space over mt_count filemarks in the positive direction.
3901  *                      The tape is positioned after the last spaced filemark.
3902  *
3903  *      MTFSFM  -       Same as MTFSF, but the tape is positioned before the
3904  *                      last filemark.
3905  *
3906  *      MTBSF   -       Steps background over mt_count filemarks, tape is
3907  *                      positioned before the last filemark.
3908  *
3909  *      MTBSFM  -       Like MTBSF, only tape is positioned after the last filemark.
3910  *
3911  *      Note:
3912  *
3913  *              MTBSF and MTBSFM are not supported when the tape doesn't
3914  *              support spacing over filemarks in the reverse direction.
3915  *              In this case, MTFSFM is also usually not supported (it is
3916  *              supported in the rare case in which we crossed the filemark
3917  *              during our read-ahead pipelined operation mode).
3918  *              
3919  *      MTWEOF  -       Writes mt_count filemarks. Tape is positioned after
3920  *                      the last written filemark.
3921  *
3922  *      MTREW   -       Rewinds tape.
3923  *
3924  *      MTLOAD  -       Loads the tape.
3925  *
3926  *      MTOFFL  -       Puts the tape drive "Offline": Rewinds the tape and
3927  *      MTUNLOAD        prevents further access until the media is replaced.
3928  *
3929  *      MTNOP   -       Flushes tape buffers.
3930  *
3931  *      MTRETEN -       Retension media. This typically consists of one end
3932  *                      to end pass on the media.
3933  *
3934  *      MTEOM   -       Moves to the end of recorded data.
3935  *
3936  *      MTERASE -       Erases tape.
3937  *
3938  *      MTSETBLK -      Sets the user block size to mt_count bytes. If
3939  *                      mt_count is 0, we will attempt to autodetect
3940  *                      the block size.
3941  *
3942  *      MTSEEK  -       Positions the tape in a specific block number, where
3943  *                      each block is assumed to contain which user_block_size
3944  *                      bytes.
3945  *
3946  *      MTSETPART -     Switches to another tape partition.
3947  *
3948  *      MTLOCK -        Locks the tape door.
3949  *
3950  *      MTUNLOCK -      Unlocks the tape door.
3951  *
3952  *      The following commands are currently not supported:
3953  *
3954  *      MTFSS, MTBSS, MTWSM, MTSETDENSITY,
3955  *      MTSETDRVBUFFER, MT_ST_BOOLEANS, MT_ST_WRITE_THRESHOLD.
3956  */
3957 static int idetape_mtioctop (ide_drive_t *drive,short mt_op,int mt_count)
3958 {
3959         idetape_tape_t *tape = drive->driver_data;
3960         idetape_pc_t pc;
3961         int i,retval;
3962
3963 #if IDETAPE_DEBUG_LOG
3964         if (tape->debug_level >= 1)
3965                 printk(KERN_INFO "ide-tape: Handling MTIOCTOP ioctl: "
3966                         "mt_op=%d, mt_count=%d\n", mt_op, mt_count);
3967 #endif /* IDETAPE_DEBUG_LOG */
3968         /*
3969          *      Commands which need our pipelined read-ahead stages.
3970          */
3971         switch (mt_op) {
3972                 case MTFSF:
3973                 case MTFSFM:
3974                 case MTBSF:
3975                 case MTBSFM:
3976                         if (!mt_count)
3977                                 return (0);
3978                         return (idetape_space_over_filemarks(drive,mt_op,mt_count));
3979                 default:
3980                         break;
3981         }
3982         switch (mt_op) {
3983                 case MTWEOF:
3984                         if (tape->write_prot)
3985                                 return -EACCES;
3986                         idetape_discard_read_pipeline(drive, 1);
3987                         for (i = 0; i < mt_count; i++) {
3988                                 retval = idetape_write_filemark(drive);
3989                                 if (retval)
3990                                         return retval;
3991                         }
3992                         return (0);
3993                 case MTREW:
3994                         idetape_discard_read_pipeline(drive, 0);
3995                         if (idetape_rewind_tape(drive))
3996                                 return -EIO;
3997                         return 0;
3998                 case MTLOAD:
3999                         idetape_discard_read_pipeline(drive, 0);
4000                         idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
4001                         return (idetape_queue_pc_tail(drive, &pc));
4002                 case MTUNLOAD:
4003                 case MTOFFL:
4004                         /*
4005                          * If door is locked, attempt to unlock before
4006                          * attempting to eject.
4007                          */
4008                         if (tape->door_locked) {
4009                                 if (idetape_create_prevent_cmd(drive, &pc, 0))
4010                                         if (!idetape_queue_pc_tail(drive, &pc))
4011                                                 tape->door_locked = DOOR_UNLOCKED;
4012                         }
4013                         idetape_discard_read_pipeline(drive, 0);
4014                         idetape_create_load_unload_cmd(drive, &pc,!IDETAPE_LU_LOAD_MASK);
4015                         retval = idetape_queue_pc_tail(drive, &pc);
4016                         if (!retval)
4017                                 clear_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
4018                         return retval;
4019                 case MTNOP:
4020                         idetape_discard_read_pipeline(drive, 0);
4021                         return (idetape_flush_tape_buffers(drive));
4022                 case MTRETEN:
4023                         idetape_discard_read_pipeline(drive, 0);
4024                         idetape_create_load_unload_cmd(drive, &pc,IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
4025                         return (idetape_queue_pc_tail(drive, &pc));
4026                 case MTEOM:
4027                         idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
4028                         return (idetape_queue_pc_tail(drive, &pc));
4029                 case MTERASE:
4030                         (void) idetape_rewind_tape(drive);
4031                         idetape_create_erase_cmd(&pc);
4032                         return (idetape_queue_pc_tail(drive, &pc));
4033                 case MTSETBLK:
4034                         if (mt_count) {
4035                                 if (mt_count < tape->tape_block_size || mt_count % tape->tape_block_size)
4036                                         return -EIO;
4037                                 tape->user_bs_factor = mt_count / tape->tape_block_size;
4038                                 clear_bit(IDETAPE_DETECT_BS, &tape->flags);
4039                         } else
4040                                 set_bit(IDETAPE_DETECT_BS, &tape->flags);
4041                         return 0;
4042                 case MTSEEK:
4043                         idetape_discard_read_pipeline(drive, 0);
4044                         return idetape_position_tape(drive, mt_count * tape->user_bs_factor, tape->partition, 0);
4045                 case MTSETPART:
4046                         idetape_discard_read_pipeline(drive, 0);
4047                         return (idetape_position_tape(drive, 0, mt_count, 0));
4048                 case MTFSR:
4049                 case MTBSR:
4050                 case MTLOCK:
4051                         if (!idetape_create_prevent_cmd(drive, &pc, 1))
4052                                 return 0;
4053                         retval = idetape_queue_pc_tail(drive, &pc);
4054                         if (retval) return retval;
4055                         tape->door_locked = DOOR_EXPLICITLY_LOCKED;
4056                         return 0;
4057                 case MTUNLOCK:
4058                         if (!idetape_create_prevent_cmd(drive, &pc, 0))
4059                                 return 0;
4060                         retval = idetape_queue_pc_tail(drive, &pc);
4061                         if (retval) return retval;
4062                         tape->door_locked = DOOR_UNLOCKED;
4063                         return 0;
4064                 default:
4065                         printk(KERN_ERR "ide-tape: MTIO operation %d not "
4066                                 "supported\n", mt_op);
4067                         return (-EIO);
4068         }
4069 }
4070
4071 /*
4072  *      Our character device ioctls.
4073  *
4074  *      General mtio.h magnetic io commands are supported here, and not in
4075  *      the corresponding block interface.
4076  *
4077  *      The following ioctls are supported:
4078  *
4079  *      MTIOCTOP -      Refer to idetape_mtioctop for detailed description.
4080  *
4081  *      MTIOCGET -      The mt_dsreg field in the returned mtget structure
4082  *                      will be set to (user block size in bytes <<
4083  *                      MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK.
4084  *
4085  *                      The mt_blkno is set to the current user block number.
4086  *                      The other mtget fields are not supported.
4087  *
4088  *      MTIOCPOS -      The current tape "block position" is returned. We
4089  *                      assume that each block contains user_block_size
4090  *                      bytes.
4091  *
4092  *      Our own ide-tape ioctls are supported on both interfaces.
4093  */
4094 static int idetape_chrdev_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
4095 {
4096         struct ide_tape_obj *tape = ide_tape_f(file);
4097         ide_drive_t *drive = tape->drive;
4098         struct mtop mtop;
4099         struct mtget mtget;
4100         struct mtpos mtpos;
4101         int block_offset = 0, position = tape->first_frame_position;
4102         void __user *argp = (void __user *)arg;
4103
4104 #if IDETAPE_DEBUG_LOG
4105         if (tape->debug_level >= 3)
4106                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_ioctl, "
4107                         "cmd=%u\n", cmd);
4108 #endif /* IDETAPE_DEBUG_LOG */
4109
4110         tape->restart_speed_control_req = 1;
4111         if (tape->chrdev_direction == idetape_direction_write) {
4112                 idetape_empty_write_pipeline(drive);
4113                 idetape_flush_tape_buffers(drive);
4114         }
4115         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
4116                 block_offset = idetape_pipeline_size(drive) / (tape->tape_block_size * tape->user_bs_factor);
4117                 if ((position = idetape_read_position(drive)) < 0)
4118                         return -EIO;
4119         }
4120         switch (cmd) {
4121                 case MTIOCTOP:
4122                         if (copy_from_user(&mtop, argp, sizeof (struct mtop)))
4123                                 return -EFAULT;
4124                         return (idetape_mtioctop(drive,mtop.mt_op,mtop.mt_count));
4125                 case MTIOCGET:
4126                         memset(&mtget, 0, sizeof (struct mtget));
4127                         mtget.mt_type = MT_ISSCSI2;
4128                         mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
4129                         mtget.mt_dsreg = ((tape->tape_block_size * tape->user_bs_factor) << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
4130                         if (tape->drv_write_prot) {
4131                                 mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
4132                         }
4133                         if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
4134                                 return -EFAULT;
4135                         return 0;
4136                 case MTIOCPOS:
4137                         mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
4138                         if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
4139                                 return -EFAULT;
4140                         return 0;
4141                 default:
4142                         if (tape->chrdev_direction == idetape_direction_read)
4143                                 idetape_discard_read_pipeline(drive, 1);
4144                         return idetape_blkdev_ioctl(drive, cmd, arg);
4145         }
4146 }
4147
4148 static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive);
4149
4150 /*
4151  *      Our character device open function.
4152  */
4153 static int idetape_chrdev_open (struct inode *inode, struct file *filp)
4154 {
4155         unsigned int minor = iminor(inode), i = minor & ~0xc0;
4156         ide_drive_t *drive;
4157         idetape_tape_t *tape;
4158         idetape_pc_t pc;
4159         int retval;
4160
4161         /*
4162          * We really want to do nonseekable_open(inode, filp); here, but some
4163          * versions of tar incorrectly call lseek on tapes and bail out if that
4164          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
4165          */
4166         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
4167
4168 #if IDETAPE_DEBUG_LOG
4169         printk(KERN_INFO "ide-tape: Reached idetape_chrdev_open\n");
4170 #endif /* IDETAPE_DEBUG_LOG */
4171         
4172         if (i >= MAX_HWIFS * MAX_DRIVES)
4173                 return -ENXIO;
4174
4175         if (!(tape = ide_tape_chrdev_get(i)))
4176                 return -ENXIO;
4177
4178         drive = tape->drive;
4179
4180         filp->private_data = tape;
4181
4182         if (test_and_set_bit(IDETAPE_BUSY, &tape->flags)) {
4183                 retval = -EBUSY;
4184                 goto out_put_tape;
4185         }
4186
4187         retval = idetape_wait_ready(drive, 60 * HZ);
4188         if (retval) {
4189                 clear_bit(IDETAPE_BUSY, &tape->flags);
4190                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
4191                 goto out_put_tape;
4192         }
4193
4194         idetape_read_position(drive);
4195         if (!test_bit(IDETAPE_ADDRESS_VALID, &tape->flags))
4196                 (void)idetape_rewind_tape(drive);
4197
4198         if (tape->chrdev_direction != idetape_direction_read)
4199                 clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
4200
4201         /* Read block size and write protect status from drive. */
4202         idetape_get_blocksize_from_block_descriptor(drive);
4203
4204         /* Set write protect flag if device is opened as read-only. */
4205         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
4206                 tape->write_prot = 1;
4207         else
4208                 tape->write_prot = tape->drv_write_prot;
4209
4210         /* Make sure drive isn't write protected if user wants to write. */
4211         if (tape->write_prot) {
4212                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
4213                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
4214                         clear_bit(IDETAPE_BUSY, &tape->flags);
4215                         retval = -EROFS;
4216                         goto out_put_tape;
4217                 }
4218         }
4219
4220         /*
4221          * Lock the tape drive door so user can't eject.
4222          */
4223         if (tape->chrdev_direction == idetape_direction_none) {
4224                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
4225                         if (!idetape_queue_pc_tail(drive, &pc)) {
4226                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
4227                                         tape->door_locked = DOOR_LOCKED;
4228                         }
4229                 }
4230         }
4231         idetape_restart_speed_control(drive);
4232         tape->restart_speed_control_req = 0;
4233         return 0;
4234
4235 out_put_tape:
4236         ide_tape_put(tape);
4237         return retval;
4238 }
4239
4240 static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
4241 {
4242         idetape_tape_t *tape = drive->driver_data;
4243
4244         idetape_empty_write_pipeline(drive);
4245         tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
4246         if (tape->merge_stage != NULL) {
4247                 idetape_pad_zeros(drive, tape->tape_block_size * (tape->user_bs_factor - 1));
4248                 __idetape_kfree_stage(tape->merge_stage);
4249                 tape->merge_stage = NULL;
4250         }
4251         idetape_write_filemark(drive);
4252         idetape_flush_tape_buffers(drive);
4253         idetape_flush_tape_buffers(drive);
4254 }
4255
4256 /*
4257  *      Our character device release function.
4258  */
4259 static int idetape_chrdev_release (struct inode *inode, struct file *filp)
4260 {
4261         struct ide_tape_obj *tape = ide_tape_f(filp);
4262         ide_drive_t *drive = tape->drive;
4263         idetape_pc_t pc;
4264         unsigned int minor = iminor(inode);
4265
4266         lock_kernel();
4267         tape = drive->driver_data;
4268 #if IDETAPE_DEBUG_LOG
4269         if (tape->debug_level >= 3)
4270                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_release\n");
4271 #endif /* IDETAPE_DEBUG_LOG */
4272
4273         if (tape->chrdev_direction == idetape_direction_write)
4274                 idetape_write_release(drive, minor);
4275         if (tape->chrdev_direction == idetape_direction_read) {
4276                 if (minor < 128)
4277                         idetape_discard_read_pipeline(drive, 1);
4278                 else
4279                         idetape_wait_for_pipeline(drive);
4280         }
4281         if (tape->cache_stage != NULL) {
4282                 __idetape_kfree_stage(tape->cache_stage);
4283                 tape->cache_stage = NULL;
4284         }
4285         if (minor < 128 && test_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags))
4286                 (void) idetape_rewind_tape(drive);
4287         if (tape->chrdev_direction == idetape_direction_none) {
4288                 if (tape->door_locked == DOOR_LOCKED) {
4289                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
4290                                 if (!idetape_queue_pc_tail(drive, &pc))
4291                                         tape->door_locked = DOOR_UNLOCKED;
4292                         }
4293                 }
4294         }
4295         clear_bit(IDETAPE_BUSY, &tape->flags);
4296         ide_tape_put(tape);
4297         unlock_kernel();
4298         return 0;
4299 }
4300
4301 /*
4302  *      idetape_identify_device is called to check the contents of the
4303  *      ATAPI IDENTIFY command results. We return:
4304  *
4305  *      1       If the tape can be supported by us, based on the information
4306  *              we have so far.
4307  *
4308  *      0       If this tape driver is not currently supported by us.
4309  */
4310 static int idetape_identify_device (ide_drive_t *drive)
4311 {
4312         struct idetape_id_gcw gcw;
4313         struct hd_driveid *id = drive->id;
4314 #if IDETAPE_DEBUG_INFO
4315         unsigned short mask,i;
4316 #endif /* IDETAPE_DEBUG_INFO */
4317
4318         if (drive->id_read == 0)
4319                 return 1;
4320
4321         *((unsigned short *) &gcw) = id->config;
4322
4323 #if IDETAPE_DEBUG_INFO
4324         printk(KERN_INFO "ide-tape: Dumping ATAPI Identify Device tape parameters\n");
4325         printk(KERN_INFO "ide-tape: Protocol Type: ");
4326         switch (gcw.protocol) {
4327                 case 0: case 1: printk("ATA\n");break;
4328                 case 2: printk("ATAPI\n");break;
4329                 case 3: printk("Reserved (Unknown to ide-tape)\n");break;
4330         }
4331         printk(KERN_INFO "ide-tape: Device Type: %x - ",gcw.device_type);       
4332         switch (gcw.device_type) {
4333                 case 0: printk("Direct-access Device\n");break;
4334                 case 1: printk("Streaming Tape Device\n");break;
4335                 case 2: case 3: case 4: printk("Reserved\n");break;
4336                 case 5: printk("CD-ROM Device\n");break;
4337                 case 6: printk("Reserved\n");
4338                 case 7: printk("Optical memory Device\n");break;
4339                 case 0x1f: printk("Unknown or no Device type\n");break;
4340                 default: printk("Reserved\n");
4341         }
4342         printk(KERN_INFO "ide-tape: Removable: %s",gcw.removable ? "Yes\n":"No\n");     
4343         printk(KERN_INFO "ide-tape: Command Packet DRQ Type: ");
4344         switch (gcw.drq_type) {
4345                 case 0: printk("Microprocessor DRQ\n");break;
4346                 case 1: printk("Interrupt DRQ\n");break;
4347                 case 2: printk("Accelerated DRQ\n");break;
4348                 case 3: printk("Reserved\n");break;
4349         }
4350         printk(KERN_INFO "ide-tape: Command Packet Size: ");
4351         switch (gcw.packet_size) {
4352                 case 0: printk("12 bytes\n");break;
4353                 case 1: printk("16 bytes\n");break;
4354                 default: printk("Reserved\n");break;
4355         }
4356         printk(KERN_INFO "ide-tape: Model: %.40s\n",id->model);
4357         printk(KERN_INFO "ide-tape: Firmware Revision: %.8s\n",id->fw_rev);
4358         printk(KERN_INFO "ide-tape: Serial Number: %.20s\n",id->serial_no);
4359         printk(KERN_INFO "ide-tape: Write buffer size: %d bytes\n",id->buf_size*512);
4360         printk(KERN_INFO "ide-tape: DMA: %s",id->capability & 0x01 ? "Yes\n":"No\n");
4361         printk(KERN_INFO "ide-tape: LBA: %s",id->capability & 0x02 ? "Yes\n":"No\n");
4362         printk(KERN_INFO "ide-tape: IORDY can be disabled: %s",id->capability & 0x04 ? "Yes\n":"No\n");
4363         printk(KERN_INFO "ide-tape: IORDY supported: %s",id->capability & 0x08 ? "Yes\n":"Unknown\n");
4364         printk(KERN_INFO "ide-tape: ATAPI overlap supported: %s",id->capability & 0x20 ? "Yes\n":"No\n");
4365         printk(KERN_INFO "ide-tape: PIO Cycle Timing Category: %d\n",id->tPIO);
4366         printk(KERN_INFO "ide-tape: DMA Cycle Timing Category: %d\n",id->tDMA);
4367         printk(KERN_INFO "ide-tape: Single Word DMA supported modes: ");
4368         for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4369                 if (id->dma_1word & mask)
4370                         printk("%d ",i);
4371                 if (id->dma_1word & (mask << 8))
4372                         printk("(active) ");
4373         }
4374         printk("\n");
4375         printk(KERN_INFO "ide-tape: Multi Word DMA supported modes: ");
4376         for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4377                 if (id->dma_mword & mask)
4378                         printk("%d ",i);
4379                 if (id->dma_mword & (mask << 8))
4380                         printk("(active) ");
4381         }
4382         printk("\n");
4383         if (id->field_valid & 0x0002) {
4384                 printk(KERN_INFO "ide-tape: Enhanced PIO Modes: %s\n",
4385                         id->eide_pio_modes & 1 ? "Mode 3":"None");
4386                 printk(KERN_INFO "ide-tape: Minimum Multi-word DMA cycle per word: ");
4387                 if (id->eide_dma_min == 0)
4388                         printk("Not supported\n");
4389                 else
4390                         printk("%d ns\n",id->eide_dma_min);
4391
4392                 printk(KERN_INFO "ide-tape: Manufacturer\'s Recommended Multi-word cycle: ");
4393                 if (id->eide_dma_time == 0)
4394                         printk("Not supported\n");
4395                 else
4396                         printk("%d ns\n",id->eide_dma_time);
4397
4398                 printk(KERN_INFO "ide-tape: Minimum PIO cycle without IORDY: ");
4399                 if (id->eide_pio == 0)
4400                         printk("Not supported\n");
4401                 else
4402                         printk("%d ns\n",id->eide_pio);
4403
4404                 printk(KERN_INFO "ide-tape: Minimum PIO cycle with IORDY: ");
4405                 if (id->eide_pio_iordy == 0)
4406                         printk("Not supported\n");
4407                 else
4408                         printk("%d ns\n",id->eide_pio_iordy);
4409                 
4410         } else
4411                 printk(KERN_INFO "ide-tape: According to the device, fields 64-70 are not valid.\n");
4412 #endif /* IDETAPE_DEBUG_INFO */
4413
4414         /* Check that we can support this device */
4415
4416         if (gcw.protocol !=2 )
4417                 printk(KERN_ERR "ide-tape: Protocol is not ATAPI\n");
4418         else if (gcw.device_type != 1)
4419                 printk(KERN_ERR "ide-tape: Device type is not set to tape\n");
4420         else if (!gcw.removable)
4421                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
4422         else if (gcw.packet_size != 0) {
4423                 printk(KERN_ERR "ide-tape: Packet size is not 12 bytes long\n");
4424                 if (gcw.packet_size == 1)
4425                         printk(KERN_ERR "ide-tape: Sorry, padding to 16 bytes is still not supported\n");
4426         } else
4427                 return 1;
4428         return 0;
4429 }
4430
4431 /*
4432  * Use INQUIRY to get the firmware revision
4433  */
4434 static void idetape_get_inquiry_results (ide_drive_t *drive)
4435 {
4436         char *r;
4437         idetape_tape_t *tape = drive->driver_data;
4438         idetape_pc_t pc;
4439         idetape_inquiry_result_t *inquiry;
4440         
4441         idetape_create_inquiry_cmd(&pc);
4442         if (idetape_queue_pc_tail(drive, &pc)) {
4443                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n", tape->name);
4444                 return;
4445         }
4446         inquiry = (idetape_inquiry_result_t *) pc.buffer;
4447         memcpy(tape->vendor_id, inquiry->vendor_id, 8);
4448         memcpy(tape->product_id, inquiry->product_id, 16);
4449         memcpy(tape->firmware_revision, inquiry->revision_level, 4);
4450         ide_fixstring(tape->vendor_id, 10, 0);
4451         ide_fixstring(tape->product_id, 18, 0);
4452         ide_fixstring(tape->firmware_revision, 6, 0);
4453         r = tape->firmware_revision;
4454         if (*(r + 1) == '.')
4455                 tape->firmware_revision_num = (*r - '0') * 100 + (*(r + 2) - '0') * 10 + *(r + 3) - '0';
4456         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n", drive->name, tape->name, tape->vendor_id, tape->product_id, tape->firmware_revision);
4457 }
4458
4459 /*
4460  *      idetape_get_mode_sense_results asks the tape about its various
4461  *      parameters. In particular, we will adjust our data transfer buffer
4462  *      size to the recommended value as returned by the tape.
4463  */
4464 static void idetape_get_mode_sense_results (ide_drive_t *drive)
4465 {
4466         idetape_tape_t *tape = drive->driver_data;
4467         idetape_pc_t pc;
4468         idetape_mode_parameter_header_t *header;
4469         idetape_capabilities_page_t *capabilities;
4470         
4471         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
4472         if (idetape_queue_pc_tail(drive, &pc)) {
4473                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming some default values\n");
4474                 tape->tape_block_size = 512;
4475                 tape->capabilities.ctl = 52;
4476                 tape->capabilities.speed = 450;
4477                 tape->capabilities.buffer_size = 6 * 52;
4478                 return;
4479         }
4480         header = (idetape_mode_parameter_header_t *) pc.buffer;
4481         capabilities = (idetape_capabilities_page_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t) + header->bdl);
4482
4483         capabilities->max_speed = ntohs(capabilities->max_speed);
4484         capabilities->ctl = ntohs(capabilities->ctl);
4485         capabilities->speed = ntohs(capabilities->speed);
4486         capabilities->buffer_size = ntohs(capabilities->buffer_size);
4487
4488         if (!capabilities->speed) {
4489                 printk(KERN_INFO "ide-tape: %s: overriding capabilities->speed (assuming 650KB/sec)\n", drive->name);
4490                 capabilities->speed = 650;
4491         }
4492         if (!capabilities->max_speed) {
4493                 printk(KERN_INFO "ide-tape: %s: overriding capabilities->max_speed (assuming 650KB/sec)\n", drive->name);
4494                 capabilities->max_speed = 650;
4495         }
4496
4497         tape->capabilities = *capabilities;             /* Save us a copy */
4498         if (capabilities->blk512)
4499                 tape->tape_block_size = 512;
4500         else if (capabilities->blk1024)
4501                 tape->tape_block_size = 1024;
4502
4503 #if IDETAPE_DEBUG_INFO
4504         printk(KERN_INFO "ide-tape: Dumping the results of the MODE SENSE packet command\n");
4505         printk(KERN_INFO "ide-tape: Mode Parameter Header:\n");
4506         printk(KERN_INFO "ide-tape: Mode Data Length - %d\n",header->mode_data_length);
4507         printk(KERN_INFO "ide-tape: Medium Type - %d\n",header->medium_type);
4508         printk(KERN_INFO "ide-tape: Device Specific Parameter - %d\n",header->dsp);
4509         printk(KERN_INFO "ide-tape: Block Descriptor Length - %d\n",header->bdl);
4510         
4511         printk(KERN_INFO "ide-tape: Capabilities and Mechanical Status Page:\n");
4512         printk(KERN_INFO "ide-tape: Page code - %d\n",capabilities->page_code);
4513         printk(KERN_INFO "ide-tape: Page length - %d\n",capabilities->page_length);
4514         printk(KERN_INFO "ide-tape: Read only - %s\n",capabilities->ro ? "Yes":"No");
4515         printk(KERN_INFO "ide-tape: Supports reverse space - %s\n",capabilities->sprev ? "Yes":"No");
4516         printk(KERN_INFO "ide-tape: Supports erase initiated formatting - %s\n",capabilities->efmt ? "Yes":"No");
4517         printk(KERN_INFO "ide-tape: Supports QFA two Partition format - %s\n",capabilities->qfa ? "Yes":"No");
4518         printk(KERN_INFO "ide-tape: Supports locking the medium - %s\n",capabilities->lock ? "Yes":"No");
4519         printk(KERN_INFO "ide-tape: The volume is currently locked - %s\n",capabilities->locked ? "Yes":"No");
4520         printk(KERN_INFO "ide-tape: The device defaults in the prevent state - %s\n",capabilities->prevent ? "Yes":"No");
4521         printk(KERN_INFO "ide-tape: Supports ejecting the medium - %s\n",capabilities->eject ? "Yes":"No");
4522         printk(KERN_INFO "ide-tape: Supports error correction - %s\n",capabilities->ecc ? "Yes":"No");
4523         printk(KERN_INFO "ide-tape: Supports data compression - %s\n",capabilities->cmprs ? "Yes":"No");
4524         printk(KERN_INFO "ide-tape: Supports 512 bytes block size - %s\n",capabilities->blk512 ? "Yes":"No");
4525         printk(KERN_INFO "ide-tape: Supports 1024 bytes block size - %s\n",capabilities->blk1024 ? "Yes":"No");
4526         printk(KERN_INFO "ide-tape: Supports 32768 bytes block size / Restricted byte count for PIO transfers - %s\n",capabilities->blk32768 ? "Yes":"No");
4527         printk(KERN_INFO "ide-tape: Maximum supported speed in KBps - %d\n",capabilities->max_speed);
4528         printk(KERN_INFO "ide-tape: Continuous transfer limits in blocks - %d\n",capabilities->ctl);
4529         printk(KERN_INFO "ide-tape: Current speed in KBps - %d\n",capabilities->speed); 
4530         printk(KERN_INFO "ide-tape: Buffer size - %d\n",capabilities->buffer_size*512);
4531 #endif /* IDETAPE_DEBUG_INFO */
4532 }
4533
4534 /*
4535  *      ide_get_blocksize_from_block_descriptor does a mode sense page 0 with block descriptor
4536  *      and if it succeeds sets the tape block size with the reported value
4537  */
4538 static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive)
4539 {
4540
4541         idetape_tape_t *tape = drive->driver_data;
4542         idetape_pc_t pc;
4543         idetape_mode_parameter_header_t *header;
4544         idetape_parameter_block_descriptor_t *block_descrp;
4545         
4546         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
4547         if (idetape_queue_pc_tail(drive, &pc)) {
4548                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
4549                 if (tape->tape_block_size == 0) {
4550                         printk(KERN_WARNING "ide-tape: Cannot deal with zero block size, assume 32k\n");
4551                         tape->tape_block_size =  32768;
4552                 }
4553                 return;
4554         }
4555         header = (idetape_mode_parameter_header_t *) pc.buffer;
4556         block_descrp = (idetape_parameter_block_descriptor_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t));
4557         tape->tape_block_size =( block_descrp->length[0]<<16) + (block_descrp->length[1]<<8) + block_descrp->length[2];
4558         tape->drv_write_prot = (header->dsp & 0x80) >> 7;
4559
4560 #if IDETAPE_DEBUG_INFO
4561         printk(KERN_INFO "ide-tape: Adjusted block size - %d\n", tape->tape_block_size);
4562 #endif /* IDETAPE_DEBUG_INFO */
4563 }
4564 static void idetape_add_settings (ide_drive_t *drive)
4565 {
4566         idetape_tape_t *tape = drive->driver_data;
4567
4568 /*
4569  *                      drive   setting name    read/write      ioctl   ioctl           data type       min                     max                     mul_factor                      div_factor                      data pointer                            set function
4570  */
4571         ide_add_setting(drive,  "buffer",       SETTING_READ,   -1,     -1,             TYPE_SHORT,     0,                      0xffff,                 1,                              2,                              &tape->capabilities.buffer_size,        NULL);
4572         ide_add_setting(drive,  "pipeline_min", SETTING_RW,     -1,     -1,             TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->min_pipeline,                    NULL);
4573         ide_add_setting(drive,  "pipeline",     SETTING_RW,     -1,     -1,             TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->max_stages,                      NULL);
4574         ide_add_setting(drive,  "pipeline_max", SETTING_RW,     -1,     -1,             TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->max_pipeline,                    NULL);
4575         ide_add_setting(drive,  "pipeline_used",SETTING_READ,   -1,     -1,             TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->nr_stages,                       NULL);
4576         ide_add_setting(drive,  "pipeline_pending",SETTING_READ,-1,     -1,             TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->nr_pending_stages,               NULL);
4577         ide_add_setting(drive,  "speed",        SETTING_READ,   -1,     -1,             TYPE_SHORT,     0,                      0xffff,                 1,                              1,                              &tape->capabilities.speed,              NULL);
4578         ide_add_setting(drive,  "stage",        SETTING_READ,   -1,     -1,             TYPE_INT,       0,                      0xffff,                 1,                              1024,                           &tape->stage_size,                      NULL);
4579         ide_add_setting(drive,  "tdsc",         SETTING_RW,     -1,     -1,             TYPE_INT,       IDETAPE_DSC_RW_MIN,     IDETAPE_DSC_RW_MAX,     1000,                           HZ,                             &tape->best_dsc_rw_frequency,           NULL);
4580         ide_add_setting(drive,  "dsc_overlap",  SETTING_RW,     -1,     -1,             TYPE_BYTE,      0,                      1,                      1,                              1,                              &drive->dsc_overlap,                    NULL);
4581         ide_add_setting(drive,  "pipeline_head_speed_c",SETTING_READ,   -1,     -1,     TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->controlled_pipeline_head_speed,  NULL);
4582         ide_add_setting(drive,  "pipeline_head_speed_u",SETTING_READ,   -1,     -1,     TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->uncontrolled_pipeline_head_speed,        NULL);
4583         ide_add_setting(drive,  "avg_speed",    SETTING_READ,   -1,     -1,             TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->avg_speed,               NULL);
4584         ide_add_setting(drive,  "debug_level",SETTING_RW,       -1,     -1,             TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->debug_level,             NULL);
4585 }
4586
4587 /*
4588  *      ide_setup is called to:
4589  *
4590  *              1.      Initialize our various state variables.
4591  *              2.      Ask the tape for its capabilities.
4592  *              3.      Allocate a buffer which will be used for data
4593  *                      transfer. The buffer size is chosen based on
4594  *                      the recommendation which we received in step (2).
4595  *
4596  *      Note that at this point ide.c already assigned us an irq, so that
4597  *      we can queue requests here and wait for their completion.
4598  */
4599 static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
4600 {
4601         unsigned long t1, tmid, tn, t;
4602         int speed;
4603         struct idetape_id_gcw gcw;
4604         int stage_size;
4605         struct sysinfo si;
4606
4607         spin_lock_init(&tape->spinlock);
4608         drive->dsc_overlap = 1;
4609 #ifdef CONFIG_BLK_DEV_IDEPCI
4610         if (HWIF(drive)->pci_dev != NULL) {
4611                 /*
4612                  * These two ide-pci host adapters appear to need DSC overlap disabled.
4613                  * This probably needs further analysis.
4614                  */
4615                 if ((HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_ARTOP_ATP850UF) ||
4616                     (HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_TTI_HPT343)) {
4617                         printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n", tape->name);
4618                         drive->dsc_overlap = 0;
4619                 }
4620         }
4621 #endif /* CONFIG_BLK_DEV_IDEPCI */
4622         /* Seagate Travan drives do not support DSC overlap. */
4623         if (strstr(drive->id->model, "Seagate STT3401"))
4624                 drive->dsc_overlap = 0;
4625         tape->minor = minor;
4626         tape->name[0] = 'h';
4627         tape->name[1] = 't';
4628         tape->name[2] = '0' + minor;
4629         tape->chrdev_direction = idetape_direction_none;
4630         tape->pc = tape->pc_stack;
4631         tape->max_insert_speed = 10000;
4632         tape->speed_control = 1;
4633         *((unsigned short *) &gcw) = drive->id->config;
4634         if (gcw.drq_type == 1)
4635                 set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
4636
4637         tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
4638         
4639         idetape_get_inquiry_results(drive);
4640         idetape_get_mode_sense_results(drive);
4641         idetape_get_blocksize_from_block_descriptor(drive);
4642         tape->user_bs_factor = 1;
4643         tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4644         while (tape->stage_size > 0xffff) {
4645                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
4646                 tape->capabilities.ctl /= 2;
4647                 tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4648         }
4649         stage_size = tape->stage_size;
4650         tape->pages_per_stage = stage_size / PAGE_SIZE;
4651         if (stage_size % PAGE_SIZE) {
4652                 tape->pages_per_stage++;
4653                 tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
4654         }
4655
4656         /*
4657          *      Select the "best" DSC read/write polling frequency
4658          *      and pipeline size.
4659          */
4660         speed = max(tape->capabilities.speed, tape->capabilities.max_speed);
4661
4662         tape->max_stages = speed * 1000 * 10 / tape->stage_size;
4663
4664         /*
4665          *      Limit memory use for pipeline to 10% of physical memory
4666          */
4667         si_meminfo(&si);
4668         if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
4669                 tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size);
4670         tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
4671         tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
4672         tape->max_pipeline = min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
4673         if (tape->max_stages == 0)
4674                 tape->max_stages = tape->min_pipeline = tape->max_pipeline = 1;
4675
4676         t1 = (tape->stage_size * HZ) / (speed * 1000);
4677         tmid = (tape->capabilities.buffer_size * 32 * HZ) / (speed * 125);
4678         tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
4679
4680         if (tape->max_stages)
4681                 t = tn;
4682         else
4683                 t = t1;
4684
4685         /*
4686          *      Ensure that the number we got makes sense; limit
4687          *      it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
4688          */
4689         tape->best_dsc_rw_frequency = max_t(unsigned long, min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), IDETAPE_DSC_RW_MIN);
4690         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
4691                 "%dkB pipeline, %lums tDSC%s\n",
4692                 drive->name, tape->name, tape->capabilities.speed,
4693                 (tape->capabilities.buffer_size * 512) / tape->stage_size,
4694                 tape->stage_size / 1024,
4695                 tape->max_stages * tape->stage_size / 1024,
4696                 tape->best_dsc_rw_frequency * 1000 / HZ,
4697                 drive->using_dma ? ", DMA":"");
4698
4699         idetape_add_settings(drive);
4700 }
4701
4702 static void ide_tape_remove(ide_drive_t *drive)
4703 {
4704         idetape_tape_t *tape = drive->driver_data;
4705
4706         ide_unregister_subdriver(drive, tape->driver);
4707
4708         ide_unregister_region(tape->disk);
4709
4710         ide_tape_put(tape);
4711 }
4712
4713 static void ide_tape_release(struct kref *kref)
4714 {
4715         struct ide_tape_obj *tape = to_ide_tape(kref);
4716         ide_drive_t *drive = tape->drive;
4717         struct gendisk *g = tape->disk;
4718
4719         BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
4720
4721         drive->dsc_overlap = 0;
4722         drive->driver_data = NULL;
4723         class_device_destroy(idetape_sysfs_class,
4724                         MKDEV(IDETAPE_MAJOR, tape->minor));
4725         class_device_destroy(idetape_sysfs_class,
4726                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
4727         idetape_devs[tape->minor] = NULL;
4728         g->private_data = NULL;
4729         put_disk(g);
4730         kfree(tape);
4731 }
4732
4733 #ifdef CONFIG_PROC_FS
4734
4735 static int proc_idetape_read_name
4736         (char *page, char **start, off_t off, int count, int *eof, void *data)
4737 {
4738         ide_drive_t     *drive = (ide_drive_t *) data;
4739         idetape_tape_t  *tape = drive->driver_data;
4740         char            *out = page;
4741         int             len;
4742
4743         len = sprintf(out, "%s\n", tape->name);
4744         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
4745 }
4746
4747 static ide_proc_entry_t idetape_proc[] = {
4748         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
4749         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
4750         { NULL, 0, NULL, NULL }
4751 };
4752
4753 #else
4754
4755 #define idetape_proc    NULL
4756
4757 #endif
4758
4759 static int ide_tape_probe(ide_drive_t *);
4760
4761 static ide_driver_t idetape_driver = {
4762         .gen_driver = {
4763                 .owner          = THIS_MODULE,
4764                 .name           = "ide-tape",
4765                 .bus            = &ide_bus_type,
4766         },
4767         .probe                  = ide_tape_probe,
4768         .remove                 = ide_tape_remove,
4769         .version                = IDETAPE_VERSION,
4770         .media                  = ide_tape,
4771         .supports_dsc_overlap   = 1,
4772         .do_request             = idetape_do_request,
4773         .end_request            = idetape_end_request,
4774         .error                  = __ide_error,
4775         .abort                  = __ide_abort,
4776         .proc                   = idetape_proc,
4777 };
4778
4779 /*
4780  *      Our character device supporting functions, passed to register_chrdev.
4781  */
4782 static struct file_operations idetape_fops = {
4783         .owner          = THIS_MODULE,
4784         .read           = idetape_chrdev_read,
4785         .write          = idetape_chrdev_write,
4786         .ioctl          = idetape_chrdev_ioctl,
4787         .open           = idetape_chrdev_open,
4788         .release        = idetape_chrdev_release,
4789 };
4790
4791 static int idetape_open(struct inode *inode, struct file *filp)
4792 {
4793         struct gendisk *disk = inode->i_bdev->bd_disk;
4794         struct ide_tape_obj *tape;
4795         ide_drive_t *drive;
4796
4797         if (!(tape = ide_tape_get(disk)))
4798                 return -ENXIO;
4799
4800         drive = tape->drive;
4801
4802         drive->usage++;
4803
4804         return 0;
4805 }
4806
4807 static int idetape_release(struct inode *inode, struct file *filp)
4808 {
4809         struct gendisk *disk = inode->i_bdev->bd_disk;
4810         struct ide_tape_obj *tape = ide_tape_g(disk);
4811         ide_drive_t *drive = tape->drive;
4812
4813         drive->usage--;
4814
4815         ide_tape_put(tape);
4816
4817         return 0;
4818 }
4819
4820 static int idetape_ioctl(struct inode *inode, struct file *file,
4821                         unsigned int cmd, unsigned long arg)
4822 {
4823         struct block_device *bdev = inode->i_bdev;
4824         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
4825         ide_drive_t *drive = tape->drive;
4826         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
4827         if (err == -EINVAL)
4828                 err = idetape_blkdev_ioctl(drive, cmd, arg);
4829         return err;
4830 }
4831
4832 static struct block_device_operations idetape_block_ops = {
4833         .owner          = THIS_MODULE,
4834         .open           = idetape_open,
4835         .release        = idetape_release,
4836         .ioctl          = idetape_ioctl,
4837 };
4838
4839 static int ide_tape_probe(ide_drive_t *drive)
4840 {
4841         idetape_tape_t *tape;
4842         struct gendisk *g;
4843         int minor;
4844
4845         if (!strstr("ide-tape", drive->driver_req))
4846                 goto failed;
4847         if (!drive->present)
4848                 goto failed;
4849         if (drive->media != ide_tape)
4850                 goto failed;
4851         if (!idetape_identify_device (drive)) {
4852                 printk(KERN_ERR "ide-tape: %s: not supported by this version of ide-tape\n", drive->name);
4853                 goto failed;
4854         }
4855         if (drive->scsi) {
4856                 printk("ide-tape: passing drive %s to ide-scsi emulation.\n", drive->name);
4857                 goto failed;
4858         }
4859         if (strstr(drive->id->model, "OnStream DI-")) {
4860                 printk(KERN_WARNING "ide-tape: Use drive %s with ide-scsi emulation and osst.\n", drive->name);
4861                 printk(KERN_WARNING "ide-tape: OnStream support will be removed soon from ide-tape!\n");
4862         }
4863         tape = (idetape_tape_t *) kzalloc (sizeof (idetape_tape_t), GFP_KERNEL);
4864         if (tape == NULL) {
4865                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape structure\n", drive->name);
4866                 goto failed;
4867         }
4868
4869         g = alloc_disk(1 << PARTN_BITS);
4870         if (!g)
4871                 goto out_free_tape;
4872
4873         ide_init_disk(g, drive);
4874
4875         ide_register_subdriver(drive, &idetape_driver);
4876
4877         kref_init(&tape->kref);
4878
4879         tape->drive = drive;
4880         tape->driver = &idetape_driver;
4881         tape->disk = g;
4882
4883         g->private_data = &tape->driver;
4884
4885         drive->driver_data = tape;
4886
4887         mutex_lock(&idetape_ref_mutex);
4888         for (minor = 0; idetape_devs[minor]; minor++)
4889                 ;
4890         idetape_devs[minor] = tape;
4891         mutex_unlock(&idetape_ref_mutex);
4892
4893         idetape_setup(drive, tape, minor);
4894
4895         class_device_create(idetape_sysfs_class, NULL,
4896                         MKDEV(IDETAPE_MAJOR, minor), &drive->gendev, "%s", tape->name);
4897         class_device_create(idetape_sysfs_class, NULL,
4898                         MKDEV(IDETAPE_MAJOR, minor + 128), &drive->gendev, "n%s", tape->name);
4899
4900         g->fops = &idetape_block_ops;
4901         ide_register_region(g);
4902
4903         return 0;
4904
4905 out_free_tape:
4906         kfree(tape);
4907 failed:
4908         return -ENODEV;
4909 }
4910
4911 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
4912 MODULE_LICENSE("GPL");
4913
4914 static void __exit idetape_exit (void)
4915 {
4916         driver_unregister(&idetape_driver.gen_driver);
4917         class_destroy(idetape_sysfs_class);
4918         unregister_chrdev(IDETAPE_MAJOR, "ht");
4919 }
4920
4921 static int __init idetape_init(void)
4922 {
4923         int error = 1;
4924         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
4925         if (IS_ERR(idetape_sysfs_class)) {
4926                 idetape_sysfs_class = NULL;
4927                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
4928                 error = -EBUSY;
4929                 goto out;
4930         }
4931
4932         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
4933                 printk(KERN_ERR "ide-tape: Failed to register character device interface\n");
4934                 error = -EBUSY;
4935                 goto out_free_class;
4936         }
4937
4938         error = driver_register(&idetape_driver.gen_driver);
4939         if (error)
4940                 goto out_free_driver;
4941
4942         return 0;
4943
4944 out_free_driver:
4945         driver_unregister(&idetape_driver.gen_driver);
4946 out_free_class:
4947         class_destroy(idetape_sysfs_class);
4948 out:
4949         return error;
4950 }
4951
4952 MODULE_ALIAS("ide:*m-tape*");
4953 module_init(idetape_init);
4954 module_exit(idetape_exit);
4955 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);