cba18a6755063c310ceb511228ddb0cdc2901683
[linux-2.6.git] / drivers / ide / ide-tape.c
1 /*
2  * IDE ATAPI streaming tape driver.
3  *
4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
6  *
7  * This driver was constructed as a student project in the software laboratory
8  * of the faculty of electrical engineering in the Technion - Israel's
9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
10  *
11  * It is hereby placed under the terms of the GNU general public license.
12  * (See linux/COPYING).
13  *
14  * For a historical changelog see
15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
16  */
17
18 #define IDETAPE_VERSION "1.20"
19
20 #include <linux/module.h>
21 #include <linux/types.h>
22 #include <linux/string.h>
23 #include <linux/kernel.h>
24 #include <linux/delay.h>
25 #include <linux/timer.h>
26 #include <linux/mm.h>
27 #include <linux/interrupt.h>
28 #include <linux/jiffies.h>
29 #include <linux/major.h>
30 #include <linux/errno.h>
31 #include <linux/genhd.h>
32 #include <linux/slab.h>
33 #include <linux/pci.h>
34 #include <linux/ide.h>
35 #include <linux/smp_lock.h>
36 #include <linux/completion.h>
37 #include <linux/bitops.h>
38 #include <linux/mutex.h>
39 #include <scsi/scsi.h>
40
41 #include <asm/byteorder.h>
42 #include <linux/irq.h>
43 #include <linux/uaccess.h>
44 #include <linux/io.h>
45 #include <asm/unaligned.h>
46 #include <linux/mtio.h>
47
48 enum {
49         /* output errors only */
50         DBG_ERR =               (1 << 0),
51         /* output all sense key/asc */
52         DBG_SENSE =             (1 << 1),
53         /* info regarding all chrdev-related procedures */
54         DBG_CHRDEV =            (1 << 2),
55         /* all remaining procedures */
56         DBG_PROCS =             (1 << 3),
57         /* buffer alloc info (pc_stack & rq_stack) */
58         DBG_PCRQ_STACK =        (1 << 4),
59 };
60
61 /* define to see debug info */
62 #define IDETAPE_DEBUG_LOG               0
63
64 #if IDETAPE_DEBUG_LOG
65 #define debug_log(lvl, fmt, args...)                    \
66 {                                                       \
67         if (tape->debug_mask & lvl)                     \
68         printk(KERN_INFO "ide-tape: " fmt, ## args);    \
69 }
70 #else
71 #define debug_log(lvl, fmt, args...) do {} while (0)
72 #endif
73
74 /**************************** Tunable parameters *****************************/
75 /*
76  * After each failed packet command we issue a request sense command and retry
77  * the packet command IDETAPE_MAX_PC_RETRIES times.
78  *
79  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
80  */
81 #define IDETAPE_MAX_PC_RETRIES          3
82
83 /*
84  * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
85  * bytes. This is used for several packet commands (Not for READ/WRITE commands)
86  */
87 #define IDETAPE_PC_BUFFER_SIZE          256
88
89 /*
90  *      In various places in the driver, we need to allocate storage
91  *      for packet commands and requests, which will remain valid while
92  *      we leave the driver to wait for an interrupt or a timeout event.
93  */
94 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
95
96 /*
97  * Some drives (for example, Seagate STT3401A Travan) require a very long
98  * timeout, because they don't return an interrupt or clear their busy bit
99  * until after the command completes (even retension commands).
100  */
101 #define IDETAPE_WAIT_CMD                (900*HZ)
102
103 /*
104  * The following parameter is used to select the point in the internal tape fifo
105  * in which we will start to refill the buffer. Decreasing the following
106  * parameter will improve the system's latency and interactive response, while
107  * using a high value might improve system throughput.
108  */
109 #define IDETAPE_FIFO_THRESHOLD          2
110
111 /*
112  * DSC polling parameters.
113  *
114  * Polling for DSC (a single bit in the status register) is a very important
115  * function in ide-tape. There are two cases in which we poll for DSC:
116  *
117  * 1. Before a read/write packet command, to ensure that we can transfer data
118  * from/to the tape's data buffers, without causing an actual media access.
119  * In case the tape is not ready yet, we take out our request from the device
120  * request queue, so that ide.c could service requests from the other device
121  * on the same interface in the meantime.
122  *
123  * 2. After the successful initialization of a "media access packet command",
124  * which is a command that can take a long time to complete (the interval can
125  * range from several seconds to even an hour). Again, we postpone our request
126  * in the middle to free the bus for the other device. The polling frequency
127  * here should be lower than the read/write frequency since those media access
128  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
129  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
130  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
131  *
132  * We also set a timeout for the timer, in case something goes wrong. The
133  * timeout should be longer then the maximum execution time of a tape operation.
134  */
135
136 /* DSC timings. */
137 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
138 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
139 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
140 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
141 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
142 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
143 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
144
145 /*************************** End of tunable parameters ***********************/
146
147 /* tape directions */
148 enum {
149         IDETAPE_DIR_NONE  = (1 << 0),
150         IDETAPE_DIR_READ  = (1 << 1),
151         IDETAPE_DIR_WRITE = (1 << 2),
152 };
153
154 struct idetape_bh {
155         u32 b_size;
156         atomic_t b_count;
157         struct idetape_bh *b_reqnext;
158         char *b_data;
159 };
160
161 /* Tape door status */
162 #define DOOR_UNLOCKED                   0
163 #define DOOR_LOCKED                     1
164 #define DOOR_EXPLICITLY_LOCKED          2
165
166 /* Some defines for the SPACE command */
167 #define IDETAPE_SPACE_OVER_FILEMARK     1
168 #define IDETAPE_SPACE_TO_EOD            3
169
170 /* Some defines for the LOAD UNLOAD command */
171 #define IDETAPE_LU_LOAD_MASK            1
172 #define IDETAPE_LU_RETENSION_MASK       2
173 #define IDETAPE_LU_EOT_MASK             4
174
175 /*
176  * Special requests for our block device strategy routine.
177  *
178  * In order to service a character device command, we add special requests to
179  * the tail of our block device request queue and wait for their completion.
180  */
181
182 enum {
183         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
184         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
185         REQ_IDETAPE_READ        = (1 << 2),
186         REQ_IDETAPE_WRITE       = (1 << 3),
187 };
188
189 /* Error codes returned in rq->errors to the higher part of the driver. */
190 #define IDETAPE_ERROR_GENERAL           101
191 #define IDETAPE_ERROR_FILEMARK          102
192 #define IDETAPE_ERROR_EOD               103
193
194 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
195 #define IDETAPE_BLOCK_DESCRIPTOR        0
196 #define IDETAPE_CAPABILITIES_PAGE       0x2a
197
198 /* Tape flag bits values. */
199 enum {
200         IDETAPE_FLAG_IGNORE_DSC         = (1 << 0),
201         /* 0 When the tape position is unknown */
202         IDETAPE_FLAG_ADDRESS_VALID      = (1 << 1),
203         /* Device already opened */
204         IDETAPE_FLAG_BUSY               = (1 << 2),
205         /* Attempt to auto-detect the current user block size */
206         IDETAPE_FLAG_DETECT_BS          = (1 << 3),
207         /* Currently on a filemark */
208         IDETAPE_FLAG_FILEMARK           = (1 << 4),
209         /* DRQ interrupt device */
210         IDETAPE_FLAG_DRQ_INTERRUPT      = (1 << 5),
211         /* 0 = no tape is loaded, so we don't rewind after ejecting */
212         IDETAPE_FLAG_MEDIUM_PRESENT     = (1 << 6),
213 };
214
215 /*
216  * Most of our global data which we need to save even as we leave the driver due
217  * to an interrupt or a timer event is stored in the struct defined below.
218  */
219 typedef struct ide_tape_obj {
220         ide_drive_t     *drive;
221         ide_driver_t    *driver;
222         struct gendisk  *disk;
223         struct kref     kref;
224
225         /*
226          *      Since a typical character device operation requires more
227          *      than one packet command, we provide here enough memory
228          *      for the maximum of interconnected packet commands.
229          *      The packet commands are stored in the circular array pc_stack.
230          *      pc_stack_index points to the last used entry, and warps around
231          *      to the start when we get to the last array entry.
232          *
233          *      pc points to the current processed packet command.
234          *
235          *      failed_pc points to the last failed packet command, or contains
236          *      NULL if we do not need to retry any packet command. This is
237          *      required since an additional packet command is needed before the
238          *      retry, to get detailed information on what went wrong.
239          */
240         /* Current packet command */
241         struct ide_atapi_pc *pc;
242         /* Last failed packet command */
243         struct ide_atapi_pc *failed_pc;
244         /* Packet command stack */
245         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
246         /* Next free packet command storage space */
247         int pc_stack_index;
248         struct request rq_stack[IDETAPE_PC_STACK];
249         /* We implement a circular array */
250         int rq_stack_index;
251
252         /*
253          * DSC polling variables.
254          *
255          * While polling for DSC we use postponed_rq to postpone the current
256          * request so that ide.c will be able to service pending requests on the
257          * other device. Note that at most we will have only one DSC (usually
258          * data transfer) request in the device request queue.
259          */
260         struct request *postponed_rq;
261         /* The time in which we started polling for DSC */
262         unsigned long dsc_polling_start;
263         /* Timer used to poll for dsc */
264         struct timer_list dsc_timer;
265         /* Read/Write dsc polling frequency */
266         unsigned long best_dsc_rw_freq;
267         unsigned long dsc_poll_freq;
268         unsigned long dsc_timeout;
269
270         /* Read position information */
271         u8 partition;
272         /* Current block */
273         unsigned int first_frame;
274
275         /* Last error information */
276         u8 sense_key, asc, ascq;
277
278         /* Character device operation */
279         unsigned int minor;
280         /* device name */
281         char name[4];
282         /* Current character device data transfer direction */
283         u8 chrdev_dir;
284
285         /* tape block size, usually 512 or 1024 bytes */
286         unsigned short blk_size;
287         int user_bs_factor;
288
289         /* Copy of the tape's Capabilities and Mechanical Page */
290         u8 caps[20];
291
292         /*
293          * Active data transfer request parameters.
294          *
295          * At most, there is only one ide-tape originated data transfer request
296          * in the device request queue. This allows ide.c to easily service
297          * requests from the other device when we postpone our active request.
298          */
299
300         /* Data buffer size chosen based on the tape's recommendation */
301         int buffer_size;
302         /* merge buffer */
303         struct idetape_bh *merge_bh;
304         /* size of the merge buffer */
305         int merge_bh_size;
306         /* pointer to current buffer head within the merge buffer */
307         struct idetape_bh *bh;
308         char *b_data;
309         int b_count;
310
311         int pages_per_buffer;
312         /* Wasted space in each stage */
313         int excess_bh_size;
314
315         /* Status/Action flags: long for set_bit */
316         unsigned long flags;
317         /* protects the ide-tape queue */
318         spinlock_t lock;
319
320         /* Measures average tape speed */
321         unsigned long avg_time;
322         int avg_size;
323         int avg_speed;
324
325         /* the door is currently locked */
326         int door_locked;
327         /* the tape hardware is write protected */
328         char drv_write_prot;
329         /* the tape is write protected (hardware or opened as read-only) */
330         char write_prot;
331
332         u32 debug_mask;
333 } idetape_tape_t;
334
335 static DEFINE_MUTEX(idetape_ref_mutex);
336
337 static struct class *idetape_sysfs_class;
338
339 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
340
341 #define ide_tape_g(disk) \
342         container_of((disk)->private_data, struct ide_tape_obj, driver)
343
344 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
345 {
346         struct ide_tape_obj *tape = NULL;
347
348         mutex_lock(&idetape_ref_mutex);
349         tape = ide_tape_g(disk);
350         if (tape)
351                 kref_get(&tape->kref);
352         mutex_unlock(&idetape_ref_mutex);
353         return tape;
354 }
355
356 static void ide_tape_release(struct kref *);
357
358 static void ide_tape_put(struct ide_tape_obj *tape)
359 {
360         mutex_lock(&idetape_ref_mutex);
361         kref_put(&tape->kref, ide_tape_release);
362         mutex_unlock(&idetape_ref_mutex);
363 }
364
365 /*
366  * The variables below are used for the character device interface. Additional
367  * state variables are defined in our ide_drive_t structure.
368  */
369 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
370
371 #define ide_tape_f(file) ((file)->private_data)
372
373 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
374 {
375         struct ide_tape_obj *tape = NULL;
376
377         mutex_lock(&idetape_ref_mutex);
378         tape = idetape_devs[i];
379         if (tape)
380                 kref_get(&tape->kref);
381         mutex_unlock(&idetape_ref_mutex);
382         return tape;
383 }
384
385 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
386                                   unsigned int bcount)
387 {
388         struct idetape_bh *bh = pc->bh;
389         int count;
390
391         while (bcount) {
392                 if (bh == NULL) {
393                         printk(KERN_ERR "ide-tape: bh == NULL in "
394                                 "idetape_input_buffers\n");
395                         ide_pad_transfer(drive, 0, bcount);
396                         return;
397                 }
398                 count = min(
399                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
400                         bcount);
401                 drive->hwif->input_data(drive, NULL, bh->b_data +
402                                         atomic_read(&bh->b_count), count);
403                 bcount -= count;
404                 atomic_add(count, &bh->b_count);
405                 if (atomic_read(&bh->b_count) == bh->b_size) {
406                         bh = bh->b_reqnext;
407                         if (bh)
408                                 atomic_set(&bh->b_count, 0);
409                 }
410         }
411         pc->bh = bh;
412 }
413
414 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
415                                    unsigned int bcount)
416 {
417         struct idetape_bh *bh = pc->bh;
418         int count;
419
420         while (bcount) {
421                 if (bh == NULL) {
422                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
423                                         __func__);
424                         return;
425                 }
426                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
427                 drive->hwif->output_data(drive, NULL, pc->b_data, count);
428                 bcount -= count;
429                 pc->b_data += count;
430                 pc->b_count -= count;
431                 if (!pc->b_count) {
432                         bh = bh->b_reqnext;
433                         pc->bh = bh;
434                         if (bh) {
435                                 pc->b_data = bh->b_data;
436                                 pc->b_count = atomic_read(&bh->b_count);
437                         }
438                 }
439         }
440 }
441
442 static void idetape_update_buffers(struct ide_atapi_pc *pc)
443 {
444         struct idetape_bh *bh = pc->bh;
445         int count;
446         unsigned int bcount = pc->xferred;
447
448         if (pc->flags & PC_FLAG_WRITING)
449                 return;
450         while (bcount) {
451                 if (bh == NULL) {
452                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
453                                         __func__);
454                         return;
455                 }
456                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
457                 atomic_set(&bh->b_count, count);
458                 if (atomic_read(&bh->b_count) == bh->b_size)
459                         bh = bh->b_reqnext;
460                 bcount -= count;
461         }
462         pc->bh = bh;
463 }
464
465 /*
466  *      idetape_next_pc_storage returns a pointer to a place in which we can
467  *      safely store a packet command, even though we intend to leave the
468  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
469  *      commands is allocated at initialization time.
470  */
471 static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
472 {
473         idetape_tape_t *tape = drive->driver_data;
474
475         debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
476
477         if (tape->pc_stack_index == IDETAPE_PC_STACK)
478                 tape->pc_stack_index = 0;
479         return (&tape->pc_stack[tape->pc_stack_index++]);
480 }
481
482 /*
483  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
484  *      Since we queue packet commands in the request queue, we need to
485  *      allocate a request, along with the allocation of a packet command.
486  */
487
488 /**************************************************************
489  *                                                            *
490  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
491  *  followed later on by kfree().   -ml                       *
492  *                                                            *
493  **************************************************************/
494
495 static struct request *idetape_next_rq_storage(ide_drive_t *drive)
496 {
497         idetape_tape_t *tape = drive->driver_data;
498
499         debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
500
501         if (tape->rq_stack_index == IDETAPE_PC_STACK)
502                 tape->rq_stack_index = 0;
503         return (&tape->rq_stack[tape->rq_stack_index++]);
504 }
505
506 /*
507  * called on each failed packet command retry to analyze the request sense. We
508  * currently do not utilize this information.
509  */
510 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
511 {
512         idetape_tape_t *tape = drive->driver_data;
513         struct ide_atapi_pc *pc = tape->failed_pc;
514
515         tape->sense_key = sense[2] & 0xF;
516         tape->asc       = sense[12];
517         tape->ascq      = sense[13];
518
519         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
520                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
521
522         /* Correct pc->xferred by asking the tape.       */
523         if (pc->flags & PC_FLAG_DMA_ERROR) {
524                 pc->xferred = pc->req_xfer -
525                         tape->blk_size *
526                         get_unaligned_be32(&sense[3]);
527                 idetape_update_buffers(pc);
528         }
529
530         /*
531          * If error was the result of a zero-length read or write command,
532          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
533          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
534          */
535         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
536             /* length == 0 */
537             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
538                 if (tape->sense_key == 5) {
539                         /* don't report an error, everything's ok */
540                         pc->error = 0;
541                         /* don't retry read/write */
542                         pc->flags |= PC_FLAG_ABORT;
543                 }
544         }
545         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
546                 pc->error = IDETAPE_ERROR_FILEMARK;
547                 pc->flags |= PC_FLAG_ABORT;
548         }
549         if (pc->c[0] == WRITE_6) {
550                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
551                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
552                         pc->error = IDETAPE_ERROR_EOD;
553                         pc->flags |= PC_FLAG_ABORT;
554                 }
555         }
556         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
557                 if (tape->sense_key == 8) {
558                         pc->error = IDETAPE_ERROR_EOD;
559                         pc->flags |= PC_FLAG_ABORT;
560                 }
561                 if (!(pc->flags & PC_FLAG_ABORT) &&
562                     pc->xferred)
563                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
564         }
565 }
566
567 /* Free data buffers completely. */
568 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
569 {
570         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
571
572         while (bh) {
573                 u32 size = bh->b_size;
574
575                 while (size) {
576                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
577
578                         if (bh->b_data)
579                                 free_pages((unsigned long)bh->b_data, order);
580
581                         size &= (order-1);
582                         bh->b_data += (1 << order) * PAGE_SIZE;
583                 }
584                 prev_bh = bh;
585                 bh = bh->b_reqnext;
586                 kfree(prev_bh);
587         }
588         kfree(tape->merge_bh);
589 }
590
591 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
592 {
593         struct request *rq = HWGROUP(drive)->rq;
594         idetape_tape_t *tape = drive->driver_data;
595         unsigned long flags;
596         int error;
597
598         debug_log(DBG_PROCS, "Enter %s\n", __func__);
599
600         switch (uptodate) {
601         case 0: error = IDETAPE_ERROR_GENERAL; break;
602         case 1: error = 0; break;
603         default: error = uptodate;
604         }
605         rq->errors = error;
606         if (error)
607                 tape->failed_pc = NULL;
608
609         if (!blk_special_request(rq)) {
610                 ide_end_request(drive, uptodate, nr_sects);
611                 return 0;
612         }
613
614         spin_lock_irqsave(&tape->lock, flags);
615
616         ide_end_drive_cmd(drive, 0, 0);
617
618         spin_unlock_irqrestore(&tape->lock, flags);
619         return 0;
620 }
621
622 static void ide_tape_callback(ide_drive_t *drive)
623 {
624         idetape_tape_t *tape = drive->driver_data;
625         struct ide_atapi_pc *pc = tape->pc;
626         int uptodate = pc->error ? 0 : 1;
627
628         debug_log(DBG_PROCS, "Enter %s\n", __func__);
629
630         if (pc->c[0] == REQUEST_SENSE) {
631                 if (uptodate)
632                         idetape_analyze_error(drive, pc->buf);
633                 else
634                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
635                                         "itself - Aborting request!\n");
636         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
637                 struct request *rq = drive->hwif->hwgroup->rq;
638                 int blocks = pc->xferred / tape->blk_size;
639
640                 tape->avg_size += blocks * tape->blk_size;
641
642                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
643                         tape->avg_speed = tape->avg_size * HZ /
644                                 (jiffies - tape->avg_time) / 1024;
645                         tape->avg_size = 0;
646                         tape->avg_time = jiffies;
647                 }
648
649                 tape->first_frame += blocks;
650                 rq->current_nr_sectors -= blocks;
651
652                 if (pc->error)
653                         uptodate = pc->error;
654         } else if (pc->c[0] == READ_POSITION && uptodate) {
655                 u8 *readpos = tape->pc->buf;
656
657                 debug_log(DBG_SENSE, "BOP - %s\n",
658                                 (readpos[0] & 0x80) ? "Yes" : "No");
659                 debug_log(DBG_SENSE, "EOP - %s\n",
660                                 (readpos[0] & 0x40) ? "Yes" : "No");
661
662                 if (readpos[0] & 0x4) {
663                         printk(KERN_INFO "ide-tape: Block location is unknown"
664                                          "to the tape\n");
665                         clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
666                         uptodate = 0;
667                 } else {
668                         debug_log(DBG_SENSE, "Block Location - %u\n",
669                                         be32_to_cpu(*(u32 *)&readpos[4]));
670
671                         tape->partition = readpos[1];
672                         tape->first_frame = be32_to_cpu(*(u32 *)&readpos[4]);
673                         set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
674                 }
675         }
676
677         idetape_end_request(drive, uptodate, 0);
678 }
679
680 static void idetape_init_pc(struct ide_atapi_pc *pc)
681 {
682         memset(pc->c, 0, 12);
683         pc->retries = 0;
684         pc->flags = 0;
685         pc->req_xfer = 0;
686         pc->buf = pc->pc_buf;
687         pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
688         pc->bh = NULL;
689         pc->b_data = NULL;
690         pc->callback = ide_tape_callback;
691 }
692
693 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
694 {
695         idetape_init_pc(pc);
696         pc->c[0] = REQUEST_SENSE;
697         pc->c[4] = 20;
698         pc->req_xfer = 20;
699 }
700
701 static void idetape_init_rq(struct request *rq, u8 cmd)
702 {
703         blk_rq_init(NULL, rq);
704         rq->cmd_type = REQ_TYPE_SPECIAL;
705         rq->cmd[0] = cmd;
706 }
707
708 /*
709  * Generate a new packet command request in front of the request queue, before
710  * the current request, so that it will be processed immediately, on the next
711  * pass through the driver. The function below is called from the request
712  * handling part of the driver (the "bottom" part). Safe storage for the request
713  * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
714  *
715  * Memory for those requests is pre-allocated at initialization time, and is
716  * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
717  * the maximum possible number of inter-dependent packet commands.
718  *
719  * The higher level of the driver - The ioctl handler and the character device
720  * handling functions should queue request to the lower level part and wait for
721  * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
722  */
723 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
724                                   struct request *rq)
725 {
726         struct ide_tape_obj *tape = drive->driver_data;
727
728         idetape_init_rq(rq, REQ_IDETAPE_PC1);
729         rq->cmd_flags |= REQ_PREEMPT;
730         rq->buffer = (char *) pc;
731         rq->rq_disk = tape->disk;
732         ide_do_drive_cmd(drive, rq);
733 }
734
735 /*
736  *      idetape_retry_pc is called when an error was detected during the
737  *      last packet command. We queue a request sense packet command in
738  *      the head of the request list.
739  */
740 static void idetape_retry_pc(ide_drive_t *drive)
741 {
742         idetape_tape_t *tape = drive->driver_data;
743         struct ide_atapi_pc *pc;
744         struct request *rq;
745
746         (void)ide_read_error(drive);
747         pc = idetape_next_pc_storage(drive);
748         rq = idetape_next_rq_storage(drive);
749         idetape_create_request_sense_cmd(pc);
750         set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
751         idetape_queue_pc_head(drive, pc, rq);
752 }
753
754 /*
755  * Postpone the current request so that ide.c will be able to service requests
756  * from another device on the same hwgroup while we are polling for DSC.
757  */
758 static void idetape_postpone_request(ide_drive_t *drive)
759 {
760         idetape_tape_t *tape = drive->driver_data;
761
762         debug_log(DBG_PROCS, "Enter %s\n", __func__);
763
764         tape->postponed_rq = HWGROUP(drive)->rq;
765         ide_stall_queue(drive, tape->dsc_poll_freq);
766 }
767
768 typedef void idetape_io_buf(ide_drive_t *, struct ide_atapi_pc *, unsigned int);
769
770 /*
771  * This is the usual interrupt handler which will be called during a packet
772  * command. We will transfer some of the data (as requested by the drive) and
773  * will re-point interrupt handler to us. When data transfer is finished, we
774  * will act according to the algorithm described before
775  * idetape_issue_pc.
776  */
777 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
778 {
779         ide_hwif_t *hwif = drive->hwif;
780         idetape_tape_t *tape = drive->driver_data;
781         struct ide_atapi_pc *pc = tape->pc;
782         xfer_func_t *xferfunc;
783         idetape_io_buf *iobuf;
784         unsigned int temp;
785         u16 bcount;
786         u8 stat, ireason;
787
788         debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
789
790         /* Clear the interrupt */
791         stat = ide_read_status(drive);
792
793         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
794                 if (hwif->dma_ops->dma_end(drive) || (stat & ERR_STAT)) {
795                         pc->flags |= PC_FLAG_DMA_ERROR;
796                 } else {
797                         pc->xferred = pc->req_xfer;
798                         idetape_update_buffers(pc);
799                 }
800                 debug_log(DBG_PROCS, "DMA finished\n");
801
802         }
803
804         /* No more interrupts */
805         if ((stat & DRQ_STAT) == 0) {
806                 debug_log(DBG_SENSE, "Packet command completed, %d bytes"
807                                 " transferred\n", pc->xferred);
808
809                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
810                 local_irq_enable_in_hardirq();
811
812                 if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
813                         stat &= ~ERR_STAT;
814                 if ((stat & ERR_STAT) || (pc->flags & PC_FLAG_DMA_ERROR)) {
815                         /* Error detected */
816                         debug_log(DBG_ERR, "%s: I/O error\n", tape->name);
817
818                         if (pc->c[0] == REQUEST_SENSE) {
819                                 printk(KERN_ERR "%s: I/O error in request sense"
820                                                 " command\n", drive->name);
821                                 return ide_do_reset(drive);
822                         }
823                         debug_log(DBG_ERR, "[cmd %x]: check condition\n",
824                                         pc->c[0]);
825
826                         /* Retry operation */
827                         idetape_retry_pc(drive);
828                         return ide_stopped;
829                 }
830                 pc->error = 0;
831                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
832                     (stat & SEEK_STAT) == 0) {
833                         /* Media access command */
834                         tape->dsc_polling_start = jiffies;
835                         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
836                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
837                         /* Allow ide.c to handle other requests */
838                         idetape_postpone_request(drive);
839                         return ide_stopped;
840                 }
841                 if (tape->failed_pc == pc)
842                         tape->failed_pc = NULL;
843                 /* Command finished - Call the callback function */
844                 pc->callback(drive);
845                 return ide_stopped;
846         }
847
848         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
849                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
850                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
851                                 "in DMA mode\n", drive->name);
852                 ide_dma_off(drive);
853                 return ide_do_reset(drive);
854         }
855         /* Get the number of bytes to transfer on this interrupt. */
856         bcount = (hwif->INB(hwif->io_ports.lbah_addr) << 8) |
857                   hwif->INB(hwif->io_ports.lbam_addr);
858
859         ireason = hwif->INB(hwif->io_ports.nsect_addr);
860
861         if (ireason & CD) {
862                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
863                 return ide_do_reset(drive);
864         }
865         if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
866                 /* Hopefully, we will never get here */
867                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
868                                 "to %s!\n", drive->name,
869                                 (ireason & IO) ? "Write" : "Read",
870                                 (ireason & IO) ? "Read" : "Write");
871                 return ide_do_reset(drive);
872         }
873         if (!(pc->flags & PC_FLAG_WRITING)) {
874                 /* Reading - Check that we have enough space */
875                 temp = pc->xferred + bcount;
876                 if (temp > pc->req_xfer) {
877                         if (temp > pc->buf_size) {
878                                 printk(KERN_ERR "%s: The device wants to send "
879                                                 "us more data than expected - "
880                                                 "discarding data\n",
881                                                 drive->name);
882                                 ide_pad_transfer(drive, 0, bcount);
883                                 ide_set_handler(drive, &idetape_pc_intr,
884                                                 IDETAPE_WAIT_CMD, NULL);
885                                 return ide_started;
886                         }
887                         debug_log(DBG_SENSE, "The device wants to send us more "
888                                 "data than expected - allowing transfer\n");
889                 }
890                 iobuf = &idetape_input_buffers;
891                 xferfunc = hwif->input_data;
892         } else {
893                 iobuf = &idetape_output_buffers;
894                 xferfunc = hwif->output_data;
895         }
896
897         if (pc->bh)
898                 iobuf(drive, pc, bcount);
899         else
900                 xferfunc(drive, NULL, pc->cur_pos, bcount);
901
902         /* Update the current position */
903         pc->xferred += bcount;
904         pc->cur_pos += bcount;
905
906         debug_log(DBG_SENSE, "[cmd %x] transferred %d bytes on that intr.\n",
907                         pc->c[0], bcount);
908
909         /* And set the interrupt handler again */
910         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
911         return ide_started;
912 }
913
914 /*
915  * Packet Command Interface
916  *
917  * The current Packet Command is available in tape->pc, and will not change
918  * until we finish handling it. Each packet command is associated with a
919  * callback function that will be called when the command is finished.
920  *
921  * The handling will be done in three stages:
922  *
923  * 1. idetape_issue_pc will send the packet command to the drive, and will set
924  * the interrupt handler to idetape_pc_intr.
925  *
926  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
927  * repeated until the device signals us that no more interrupts will be issued.
928  *
929  * 3. ATAPI Tape media access commands have immediate status with a delayed
930  * process. In case of a successful initiation of a media access packet command,
931  * the DSC bit will be set when the actual execution of the command is finished.
932  * Since the tape drive will not issue an interrupt, we have to poll for this
933  * event. In this case, we define the request as "low priority request" by
934  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
935  * exit the driver.
936  *
937  * ide.c will then give higher priority to requests which originate from the
938  * other device, until will change rq_status to RQ_ACTIVE.
939  *
940  * 4. When the packet command is finished, it will be checked for errors.
941  *
942  * 5. In case an error was found, we queue a request sense packet command in
943  * front of the request queue and retry the operation up to
944  * IDETAPE_MAX_PC_RETRIES times.
945  *
946  * 6. In case no error was found, or we decided to give up and not to retry
947  * again, the callback function will be called and then we will handle the next
948  * request.
949  */
950 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
951 {
952         idetape_tape_t *tape = drive->driver_data;
953
954         return ide_transfer_pc(drive, tape->pc, idetape_pc_intr,
955                                IDETAPE_WAIT_CMD, NULL);
956 }
957
958 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
959                 struct ide_atapi_pc *pc)
960 {
961         ide_hwif_t *hwif = drive->hwif;
962         idetape_tape_t *tape = drive->driver_data;
963         int dma_ok = 0;
964         u16 bcount;
965
966         if (tape->pc->c[0] == REQUEST_SENSE &&
967             pc->c[0] == REQUEST_SENSE) {
968                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
969                         "Two request sense in serial were issued\n");
970         }
971
972         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
973                 tape->failed_pc = pc;
974         /* Set the current packet command */
975         tape->pc = pc;
976
977         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
978                 (pc->flags & PC_FLAG_ABORT)) {
979                 /*
980                  * We will "abort" retrying a packet command in case legitimate
981                  * error code was received (crossing a filemark, or end of the
982                  * media, for example).
983                  */
984                 if (!(pc->flags & PC_FLAG_ABORT)) {
985                         if (!(pc->c[0] == TEST_UNIT_READY &&
986                               tape->sense_key == 2 && tape->asc == 4 &&
987                              (tape->ascq == 1 || tape->ascq == 8))) {
988                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
989                                                 "pc = %2x, key = %2x, "
990                                                 "asc = %2x, ascq = %2x\n",
991                                                 tape->name, pc->c[0],
992                                                 tape->sense_key, tape->asc,
993                                                 tape->ascq);
994                         }
995                         /* Giving up */
996                         pc->error = IDETAPE_ERROR_GENERAL;
997                 }
998                 tape->failed_pc = NULL;
999                 pc->callback(drive);
1000                 return ide_stopped;
1001         }
1002         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
1003
1004         pc->retries++;
1005         /* We haven't transferred any data yet */
1006         pc->xferred = 0;
1007         pc->cur_pos = pc->buf;
1008         /* Request to transfer the entire buffer at once */
1009         bcount = pc->req_xfer;
1010
1011         if (pc->flags & PC_FLAG_DMA_ERROR) {
1012                 pc->flags &= ~PC_FLAG_DMA_ERROR;
1013                 ide_dma_off(drive);
1014         }
1015         if ((pc->flags & PC_FLAG_DMA_OK) && drive->using_dma)
1016                 dma_ok = !hwif->dma_ops->dma_setup(drive);
1017
1018         if (!dma_ok)
1019                 pc->flags &= ~PC_FLAG_DMA_OK;
1020
1021         ide_pktcmd_tf_load(drive, IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
1022
1023         if (pc->flags & PC_FLAG_DRQ_INTERRUPT) {
1024                 ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
1025                                     IDETAPE_WAIT_CMD, NULL);
1026                 return ide_started;
1027         } else {
1028                 ide_execute_pkt_cmd(drive);
1029                 return idetape_transfer_pc(drive);
1030         }
1031 }
1032
1033 /* A mode sense command is used to "sense" tape parameters. */
1034 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
1035 {
1036         idetape_init_pc(pc);
1037         pc->c[0] = MODE_SENSE;
1038         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1039                 /* DBD = 1 - Don't return block descriptors */
1040                 pc->c[1] = 8;
1041         pc->c[2] = page_code;
1042         /*
1043          * Changed pc->c[3] to 0 (255 will at best return unused info).
1044          *
1045          * For SCSI this byte is defined as subpage instead of high byte
1046          * of length and some IDE drives seem to interpret it this way
1047          * and return an error when 255 is used.
1048          */
1049         pc->c[3] = 0;
1050         /* We will just discard data in that case */
1051         pc->c[4] = 255;
1052         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1053                 pc->req_xfer = 12;
1054         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
1055                 pc->req_xfer = 24;
1056         else
1057                 pc->req_xfer = 50;
1058 }
1059
1060 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
1061 {
1062         idetape_tape_t *tape = drive->driver_data;
1063         struct ide_atapi_pc *pc = tape->pc;
1064         u8 stat;
1065
1066         stat = ide_read_status(drive);
1067
1068         if (stat & SEEK_STAT) {
1069                 if (stat & ERR_STAT) {
1070                         /* Error detected */
1071                         if (pc->c[0] != TEST_UNIT_READY)
1072                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
1073                                                 tape->name);
1074                         /* Retry operation */
1075                         idetape_retry_pc(drive);
1076                         return ide_stopped;
1077                 }
1078                 pc->error = 0;
1079                 if (tape->failed_pc == pc)
1080                         tape->failed_pc = NULL;
1081         } else {
1082                 pc->error = IDETAPE_ERROR_GENERAL;
1083                 tape->failed_pc = NULL;
1084         }
1085         pc->callback(drive);
1086         return ide_stopped;
1087 }
1088
1089 static void idetape_create_read_cmd(idetape_tape_t *tape,
1090                 struct ide_atapi_pc *pc,
1091                 unsigned int length, struct idetape_bh *bh)
1092 {
1093         idetape_init_pc(pc);
1094         pc->c[0] = READ_6;
1095         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1096         pc->c[1] = 1;
1097         pc->bh = bh;
1098         atomic_set(&bh->b_count, 0);
1099         pc->buf = NULL;
1100         pc->buf_size = length * tape->blk_size;
1101         pc->req_xfer = pc->buf_size;
1102         if (pc->req_xfer == tape->buffer_size)
1103                 pc->flags |= PC_FLAG_DMA_OK;
1104 }
1105
1106 static void idetape_create_write_cmd(idetape_tape_t *tape,
1107                 struct ide_atapi_pc *pc,
1108                 unsigned int length, struct idetape_bh *bh)
1109 {
1110         idetape_init_pc(pc);
1111         pc->c[0] = WRITE_6;
1112         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1113         pc->c[1] = 1;
1114         pc->flags |= PC_FLAG_WRITING;
1115         pc->bh = bh;
1116         pc->b_data = bh->b_data;
1117         pc->b_count = atomic_read(&bh->b_count);
1118         pc->buf = NULL;
1119         pc->buf_size = length * tape->blk_size;
1120         pc->req_xfer = pc->buf_size;
1121         if (pc->req_xfer == tape->buffer_size)
1122                 pc->flags |= PC_FLAG_DMA_OK;
1123 }
1124
1125 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1126                                           struct request *rq, sector_t block)
1127 {
1128         idetape_tape_t *tape = drive->driver_data;
1129         struct ide_atapi_pc *pc = NULL;
1130         struct request *postponed_rq = tape->postponed_rq;
1131         u8 stat;
1132
1133         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
1134                         " current_nr_sectors: %d\n",
1135                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1136
1137         if (!blk_special_request(rq)) {
1138                 /* We do not support buffer cache originated requests. */
1139                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1140                         "request queue (%d)\n", drive->name, rq->cmd_type);
1141                 ide_end_request(drive, 0, 0);
1142                 return ide_stopped;
1143         }
1144
1145         /* Retry a failed packet command */
1146         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE) {
1147                 pc = tape->failed_pc;
1148                 goto out;
1149         }
1150
1151         if (postponed_rq != NULL)
1152                 if (rq != postponed_rq) {
1153                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1154                                         "Two DSC requests were queued\n");
1155                         idetape_end_request(drive, 0, 0);
1156                         return ide_stopped;
1157                 }
1158
1159         tape->postponed_rq = NULL;
1160
1161         /*
1162          * If the tape is still busy, postpone our request and service
1163          * the other device meanwhile.
1164          */
1165         stat = ide_read_status(drive);
1166
1167         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
1168                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1169
1170         if (drive->post_reset == 1) {
1171                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1172                 drive->post_reset = 0;
1173         }
1174
1175         if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&
1176             (stat & SEEK_STAT) == 0) {
1177                 if (postponed_rq == NULL) {
1178                         tape->dsc_polling_start = jiffies;
1179                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1180                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1181                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1182                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1183                                 tape->name);
1184                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1185                                 idetape_media_access_finished(drive);
1186                                 return ide_stopped;
1187                         } else {
1188                                 return ide_do_reset(drive);
1189                         }
1190                 } else if (time_after(jiffies,
1191                                         tape->dsc_polling_start +
1192                                         IDETAPE_DSC_MA_THRESHOLD))
1193                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1194                 idetape_postpone_request(drive);
1195                 return ide_stopped;
1196         }
1197         if (rq->cmd[0] & REQ_IDETAPE_READ) {
1198                 pc = idetape_next_pc_storage(drive);
1199                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
1200                                         (struct idetape_bh *)rq->special);
1201                 goto out;
1202         }
1203         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1204                 pc = idetape_next_pc_storage(drive);
1205                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
1206                                          (struct idetape_bh *)rq->special);
1207                 goto out;
1208         }
1209         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
1210                 pc = (struct ide_atapi_pc *) rq->buffer;
1211                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
1212                 rq->cmd[0] |= REQ_IDETAPE_PC2;
1213                 goto out;
1214         }
1215         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1216                 idetape_media_access_finished(drive);
1217                 return ide_stopped;
1218         }
1219         BUG();
1220 out:
1221         if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags))
1222                 pc->flags |= PC_FLAG_DRQ_INTERRUPT;
1223
1224         return idetape_issue_pc(drive, pc);
1225 }
1226
1227 /*
1228  * The function below uses __get_free_pages to allocate a data buffer of size
1229  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
1230  * much as possible.
1231  *
1232  * It returns a pointer to the newly allocated buffer, or NULL in case of
1233  * failure.
1234  */
1235 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
1236                                                   int full, int clear)
1237 {
1238         struct idetape_bh *prev_bh, *bh, *merge_bh;
1239         int pages = tape->pages_per_buffer;
1240         unsigned int order, b_allocd;
1241         char *b_data = NULL;
1242
1243         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1244         bh = merge_bh;
1245         if (bh == NULL)
1246                 goto abort;
1247
1248         order = fls(pages) - 1;
1249         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1250         if (!bh->b_data)
1251                 goto abort;
1252         b_allocd = (1 << order) * PAGE_SIZE;
1253         pages &= (order-1);
1254
1255         if (clear)
1256                 memset(bh->b_data, 0, b_allocd);
1257         bh->b_reqnext = NULL;
1258         bh->b_size = b_allocd;
1259         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1260
1261         while (pages) {
1262                 order = fls(pages) - 1;
1263                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1264                 if (!b_data)
1265                         goto abort;
1266                 b_allocd = (1 << order) * PAGE_SIZE;
1267
1268                 if (clear)
1269                         memset(b_data, 0, b_allocd);
1270
1271                 /* newly allocated page frames below buffer header or ...*/
1272                 if (bh->b_data == b_data + b_allocd) {
1273                         bh->b_size += b_allocd;
1274                         bh->b_data -= b_allocd;
1275                         if (full)
1276                                 atomic_add(b_allocd, &bh->b_count);
1277                         continue;
1278                 }
1279                 /* they are above the header */
1280                 if (b_data == bh->b_data + bh->b_size) {
1281                         bh->b_size += b_allocd;
1282                         if (full)
1283                                 atomic_add(b_allocd, &bh->b_count);
1284                         continue;
1285                 }
1286                 prev_bh = bh;
1287                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1288                 if (!bh) {
1289                         free_pages((unsigned long) b_data, order);
1290                         goto abort;
1291                 }
1292                 bh->b_reqnext = NULL;
1293                 bh->b_data = b_data;
1294                 bh->b_size = b_allocd;
1295                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1296                 prev_bh->b_reqnext = bh;
1297
1298                 pages &= (order-1);
1299         }
1300
1301         bh->b_size -= tape->excess_bh_size;
1302         if (full)
1303                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1304         return merge_bh;
1305 abort:
1306         ide_tape_kfree_buffer(tape);
1307         return NULL;
1308 }
1309
1310 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1311                                         const char __user *buf, int n)
1312 {
1313         struct idetape_bh *bh = tape->bh;
1314         int count;
1315         int ret = 0;
1316
1317         while (n) {
1318                 if (bh == NULL) {
1319                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1320                                         __func__);
1321                         return 1;
1322                 }
1323                 count = min((unsigned int)
1324                                 (bh->b_size - atomic_read(&bh->b_count)),
1325                                 (unsigned int)n);
1326                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1327                                 count))
1328                         ret = 1;
1329                 n -= count;
1330                 atomic_add(count, &bh->b_count);
1331                 buf += count;
1332                 if (atomic_read(&bh->b_count) == bh->b_size) {
1333                         bh = bh->b_reqnext;
1334                         if (bh)
1335                                 atomic_set(&bh->b_count, 0);
1336                 }
1337         }
1338         tape->bh = bh;
1339         return ret;
1340 }
1341
1342 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1343                                       int n)
1344 {
1345         struct idetape_bh *bh = tape->bh;
1346         int count;
1347         int ret = 0;
1348
1349         while (n) {
1350                 if (bh == NULL) {
1351                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1352                                         __func__);
1353                         return 1;
1354                 }
1355                 count = min(tape->b_count, n);
1356                 if  (copy_to_user(buf, tape->b_data, count))
1357                         ret = 1;
1358                 n -= count;
1359                 tape->b_data += count;
1360                 tape->b_count -= count;
1361                 buf += count;
1362                 if (!tape->b_count) {
1363                         bh = bh->b_reqnext;
1364                         tape->bh = bh;
1365                         if (bh) {
1366                                 tape->b_data = bh->b_data;
1367                                 tape->b_count = atomic_read(&bh->b_count);
1368                         }
1369                 }
1370         }
1371         return ret;
1372 }
1373
1374 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1375 {
1376         struct idetape_bh *bh = tape->merge_bh;
1377         tape->bh = tape->merge_bh;
1378
1379         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1380                 atomic_set(&bh->b_count, 0);
1381         else {
1382                 tape->b_data = bh->b_data;
1383                 tape->b_count = atomic_read(&bh->b_count);
1384         }
1385 }
1386
1387 /*
1388  * Write a filemark if write_filemark=1. Flush the device buffers without
1389  * writing a filemark otherwise.
1390  */
1391 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1392                 struct ide_atapi_pc *pc, int write_filemark)
1393 {
1394         idetape_init_pc(pc);
1395         pc->c[0] = WRITE_FILEMARKS;
1396         pc->c[4] = write_filemark;
1397         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1398 }
1399
1400 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1401 {
1402         idetape_init_pc(pc);
1403         pc->c[0] = TEST_UNIT_READY;
1404 }
1405
1406 /*
1407  * We add a special packet command request to the tail of the request queue, and
1408  * wait for it to be serviced. This is not to be called from within the request
1409  * handling part of the driver! We allocate here data on the stack and it is
1410  * valid until the request is finished. This is not the case for the bottom part
1411  * of the driver, where we are always leaving the functions to wait for an
1412  * interrupt or a timer event.
1413  *
1414  * From the bottom part of the driver, we should allocate safe memory using
1415  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1416  * to the request list without waiting for it to be serviced! In that case, we
1417  * usually use idetape_queue_pc_head().
1418  */
1419 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1420 {
1421         struct ide_tape_obj *tape = drive->driver_data;
1422         struct request *rq;
1423         int error;
1424
1425         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1426         rq->cmd_type = REQ_TYPE_SPECIAL;
1427         rq->cmd[0] = REQ_IDETAPE_PC1;
1428         rq->buffer = (char *)pc;
1429         error = blk_execute_rq(drive->queue, tape->disk, rq, 0);
1430         blk_put_request(rq);
1431         return error;
1432 }
1433
1434 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1435                 struct ide_atapi_pc *pc, int cmd)
1436 {
1437         idetape_init_pc(pc);
1438         pc->c[0] = START_STOP;
1439         pc->c[4] = cmd;
1440         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1441 }
1442
1443 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1444 {
1445         idetape_tape_t *tape = drive->driver_data;
1446         struct ide_atapi_pc pc;
1447         int load_attempted = 0;
1448
1449         /* Wait for the tape to become ready */
1450         set_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
1451         timeout += jiffies;
1452         while (time_before(jiffies, timeout)) {
1453                 idetape_create_test_unit_ready_cmd(&pc);
1454                 if (!idetape_queue_pc_tail(drive, &pc))
1455                         return 0;
1456                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1457                     || (tape->asc == 0x3A)) {
1458                         /* no media */
1459                         if (load_attempted)
1460                                 return -ENOMEDIUM;
1461                         idetape_create_load_unload_cmd(drive, &pc,
1462                                                         IDETAPE_LU_LOAD_MASK);
1463                         idetape_queue_pc_tail(drive, &pc);
1464                         load_attempted = 1;
1465                 /* not about to be ready */
1466                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1467                              (tape->ascq == 1 || tape->ascq == 8)))
1468                         return -EIO;
1469                 msleep(100);
1470         }
1471         return -EIO;
1472 }
1473
1474 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1475 {
1476         struct ide_atapi_pc pc;
1477         int rc;
1478
1479         idetape_create_write_filemark_cmd(drive, &pc, 0);
1480         rc = idetape_queue_pc_tail(drive, &pc);
1481         if (rc)
1482                 return rc;
1483         idetape_wait_ready(drive, 60 * 5 * HZ);
1484         return 0;
1485 }
1486
1487 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1488 {
1489         idetape_init_pc(pc);
1490         pc->c[0] = READ_POSITION;
1491         pc->req_xfer = 20;
1492 }
1493
1494 static int idetape_read_position(ide_drive_t *drive)
1495 {
1496         idetape_tape_t *tape = drive->driver_data;
1497         struct ide_atapi_pc pc;
1498         int position;
1499
1500         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1501
1502         idetape_create_read_position_cmd(&pc);
1503         if (idetape_queue_pc_tail(drive, &pc))
1504                 return -1;
1505         position = tape->first_frame;
1506         return position;
1507 }
1508
1509 static void idetape_create_locate_cmd(ide_drive_t *drive,
1510                 struct ide_atapi_pc *pc,
1511                 unsigned int block, u8 partition, int skip)
1512 {
1513         idetape_init_pc(pc);
1514         pc->c[0] = POSITION_TO_ELEMENT;
1515         pc->c[1] = 2;
1516         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1517         pc->c[8] = partition;
1518         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1519 }
1520
1521 static int idetape_create_prevent_cmd(ide_drive_t *drive,
1522                 struct ide_atapi_pc *pc, int prevent)
1523 {
1524         idetape_tape_t *tape = drive->driver_data;
1525
1526         /* device supports locking according to capabilities page */
1527         if (!(tape->caps[6] & 0x01))
1528                 return 0;
1529
1530         idetape_init_pc(pc);
1531         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
1532         pc->c[4] = prevent;
1533         return 1;
1534 }
1535
1536 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1537 {
1538         idetape_tape_t *tape = drive->driver_data;
1539
1540         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1541                 return;
1542
1543         clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
1544         tape->merge_bh_size = 0;
1545         if (tape->merge_bh != NULL) {
1546                 ide_tape_kfree_buffer(tape);
1547                 tape->merge_bh = NULL;
1548         }
1549
1550         tape->chrdev_dir = IDETAPE_DIR_NONE;
1551 }
1552
1553 /*
1554  * Position the tape to the requested block using the LOCATE packet command.
1555  * A READ POSITION command is then issued to check where we are positioned. Like
1556  * all higher level operations, we queue the commands at the tail of the request
1557  * queue and wait for their completion.
1558  */
1559 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1560                 u8 partition, int skip)
1561 {
1562         idetape_tape_t *tape = drive->driver_data;
1563         int retval;
1564         struct ide_atapi_pc pc;
1565
1566         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1567                 __ide_tape_discard_merge_buffer(drive);
1568         idetape_wait_ready(drive, 60 * 5 * HZ);
1569         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1570         retval = idetape_queue_pc_tail(drive, &pc);
1571         if (retval)
1572                 return (retval);
1573
1574         idetape_create_read_position_cmd(&pc);
1575         return (idetape_queue_pc_tail(drive, &pc));
1576 }
1577
1578 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1579                                           int restore_position)
1580 {
1581         idetape_tape_t *tape = drive->driver_data;
1582         int seek, position;
1583
1584         __ide_tape_discard_merge_buffer(drive);
1585         if (restore_position) {
1586                 position = idetape_read_position(drive);
1587                 seek = position > 0 ? position : 0;
1588                 if (idetape_position_tape(drive, seek, 0, 0)) {
1589                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1590                                          " %s\n", tape->name, __func__);
1591                         return;
1592                 }
1593         }
1594 }
1595
1596 /*
1597  * Generate a read/write request for the block device interface and wait for it
1598  * to be serviced.
1599  */
1600 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1601                                  struct idetape_bh *bh)
1602 {
1603         idetape_tape_t *tape = drive->driver_data;
1604         struct request *rq;
1605         int ret, errors;
1606
1607         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1608
1609         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1610         rq->cmd_type = REQ_TYPE_SPECIAL;
1611         rq->cmd[0] = cmd;
1612         rq->rq_disk = tape->disk;
1613         rq->special = (void *)bh;
1614         rq->sector = tape->first_frame;
1615         rq->nr_sectors = blocks;
1616         rq->current_nr_sectors = blocks;
1617         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1618
1619         errors = rq->errors;
1620         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1621         blk_put_request(rq);
1622
1623         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1624                 return 0;
1625
1626         if (tape->merge_bh)
1627                 idetape_init_merge_buffer(tape);
1628         if (errors == IDETAPE_ERROR_GENERAL)
1629                 return -EIO;
1630         return ret;
1631 }
1632
1633 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1634 {
1635         idetape_init_pc(pc);
1636         pc->c[0] = INQUIRY;
1637         pc->c[4] = 254;
1638         pc->req_xfer = 254;
1639 }
1640
1641 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1642                 struct ide_atapi_pc *pc)
1643 {
1644         idetape_init_pc(pc);
1645         pc->c[0] = REZERO_UNIT;
1646         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1647 }
1648
1649 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1650 {
1651         idetape_init_pc(pc);
1652         pc->c[0] = ERASE;
1653         pc->c[1] = 1;
1654         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1655 }
1656
1657 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1658 {
1659         idetape_init_pc(pc);
1660         pc->c[0] = SPACE;
1661         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1662         pc->c[1] = cmd;
1663         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1664 }
1665
1666 /* Queue up a character device originated write request. */
1667 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1668 {
1669         idetape_tape_t *tape = drive->driver_data;
1670
1671         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1672
1673         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1674                                      blocks, tape->merge_bh);
1675 }
1676
1677 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1678 {
1679         idetape_tape_t *tape = drive->driver_data;
1680         int blocks, min;
1681         struct idetape_bh *bh;
1682
1683         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1684                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1685                                 " but we are not writing.\n");
1686                 return;
1687         }
1688         if (tape->merge_bh_size > tape->buffer_size) {
1689                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1690                 tape->merge_bh_size = tape->buffer_size;
1691         }
1692         if (tape->merge_bh_size) {
1693                 blocks = tape->merge_bh_size / tape->blk_size;
1694                 if (tape->merge_bh_size % tape->blk_size) {
1695                         unsigned int i;
1696
1697                         blocks++;
1698                         i = tape->blk_size - tape->merge_bh_size %
1699                                 tape->blk_size;
1700                         bh = tape->bh->b_reqnext;
1701                         while (bh) {
1702                                 atomic_set(&bh->b_count, 0);
1703                                 bh = bh->b_reqnext;
1704                         }
1705                         bh = tape->bh;
1706                         while (i) {
1707                                 if (bh == NULL) {
1708                                         printk(KERN_INFO "ide-tape: bug,"
1709                                                          " bh NULL\n");
1710                                         break;
1711                                 }
1712                                 min = min(i, (unsigned int)(bh->b_size -
1713                                                 atomic_read(&bh->b_count)));
1714                                 memset(bh->b_data + atomic_read(&bh->b_count),
1715                                                 0, min);
1716                                 atomic_add(min, &bh->b_count);
1717                                 i -= min;
1718                                 bh = bh->b_reqnext;
1719                         }
1720                 }
1721                 (void) idetape_add_chrdev_write_request(drive, blocks);
1722                 tape->merge_bh_size = 0;
1723         }
1724         if (tape->merge_bh != NULL) {
1725                 ide_tape_kfree_buffer(tape);
1726                 tape->merge_bh = NULL;
1727         }
1728         tape->chrdev_dir = IDETAPE_DIR_NONE;
1729 }
1730
1731 static int idetape_init_read(ide_drive_t *drive)
1732 {
1733         idetape_tape_t *tape = drive->driver_data;
1734         int bytes_read;
1735
1736         /* Initialize read operation */
1737         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1738                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1739                         ide_tape_flush_merge_buffer(drive);
1740                         idetape_flush_tape_buffers(drive);
1741                 }
1742                 if (tape->merge_bh || tape->merge_bh_size) {
1743                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1744                                          " 0 now\n");
1745                         tape->merge_bh_size = 0;
1746                 }
1747                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1748                 if (!tape->merge_bh)
1749                         return -ENOMEM;
1750                 tape->chrdev_dir = IDETAPE_DIR_READ;
1751
1752                 /*
1753                  * Issue a read 0 command to ensure that DSC handshake is
1754                  * switched from completion mode to buffer available mode.
1755                  * No point in issuing this if DSC overlap isn't supported, some
1756                  * drives (Seagate STT3401A) will return an error.
1757                  */
1758                 if (drive->dsc_overlap) {
1759                         bytes_read = idetape_queue_rw_tail(drive,
1760                                                         REQ_IDETAPE_READ, 0,
1761                                                         tape->merge_bh);
1762                         if (bytes_read < 0) {
1763                                 ide_tape_kfree_buffer(tape);
1764                                 tape->merge_bh = NULL;
1765                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1766                                 return bytes_read;
1767                         }
1768                 }
1769         }
1770
1771         return 0;
1772 }
1773
1774 /* called from idetape_chrdev_read() to service a chrdev read request. */
1775 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1776 {
1777         idetape_tape_t *tape = drive->driver_data;
1778
1779         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1780
1781         /* If we are at a filemark, return a read length of 0 */
1782         if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1783                 return 0;
1784
1785         idetape_init_read(drive);
1786
1787         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1788                                      tape->merge_bh);
1789 }
1790
1791 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1792 {
1793         idetape_tape_t *tape = drive->driver_data;
1794         struct idetape_bh *bh;
1795         int blocks;
1796
1797         while (bcount) {
1798                 unsigned int count;
1799
1800                 bh = tape->merge_bh;
1801                 count = min(tape->buffer_size, bcount);
1802                 bcount -= count;
1803                 blocks = count / tape->blk_size;
1804                 while (count) {
1805                         atomic_set(&bh->b_count,
1806                                    min(count, (unsigned int)bh->b_size));
1807                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1808                         count -= atomic_read(&bh->b_count);
1809                         bh = bh->b_reqnext;
1810                 }
1811                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1812                                       tape->merge_bh);
1813         }
1814 }
1815
1816 /*
1817  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1818  * currently support only one partition.
1819  */
1820 static int idetape_rewind_tape(ide_drive_t *drive)
1821 {
1822         int retval;
1823         struct ide_atapi_pc pc;
1824         idetape_tape_t *tape;
1825         tape = drive->driver_data;
1826
1827         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1828
1829         idetape_create_rewind_cmd(drive, &pc);
1830         retval = idetape_queue_pc_tail(drive, &pc);
1831         if (retval)
1832                 return retval;
1833
1834         idetape_create_read_position_cmd(&pc);
1835         retval = idetape_queue_pc_tail(drive, &pc);
1836         if (retval)
1837                 return retval;
1838         return 0;
1839 }
1840
1841 /* mtio.h compatible commands should be issued to the chrdev interface. */
1842 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1843                                 unsigned long arg)
1844 {
1845         idetape_tape_t *tape = drive->driver_data;
1846         void __user *argp = (void __user *)arg;
1847
1848         struct idetape_config {
1849                 int dsc_rw_frequency;
1850                 int dsc_media_access_frequency;
1851                 int nr_stages;
1852         } config;
1853
1854         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1855
1856         switch (cmd) {
1857         case 0x0340:
1858                 if (copy_from_user(&config, argp, sizeof(config)))
1859                         return -EFAULT;
1860                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1861                 break;
1862         case 0x0350:
1863                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1864                 config.nr_stages = 1;
1865                 if (copy_to_user(argp, &config, sizeof(config)))
1866                         return -EFAULT;
1867                 break;
1868         default:
1869                 return -EIO;
1870         }
1871         return 0;
1872 }
1873
1874 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1875                                         int mt_count)
1876 {
1877         idetape_tape_t *tape = drive->driver_data;
1878         struct ide_atapi_pc pc;
1879         int retval, count = 0;
1880         int sprev = !!(tape->caps[4] & 0x20);
1881
1882         if (mt_count == 0)
1883                 return 0;
1884         if (MTBSF == mt_op || MTBSFM == mt_op) {
1885                 if (!sprev)
1886                         return -EIO;
1887                 mt_count = -mt_count;
1888         }
1889
1890         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1891                 tape->merge_bh_size = 0;
1892                 if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1893                         ++count;
1894                 ide_tape_discard_merge_buffer(drive, 0);
1895         }
1896
1897         switch (mt_op) {
1898         case MTFSF:
1899         case MTBSF:
1900                 idetape_create_space_cmd(&pc, mt_count - count,
1901                                          IDETAPE_SPACE_OVER_FILEMARK);
1902                 return idetape_queue_pc_tail(drive, &pc);
1903         case MTFSFM:
1904         case MTBSFM:
1905                 if (!sprev)
1906                         return -EIO;
1907                 retval = idetape_space_over_filemarks(drive, MTFSF,
1908                                                       mt_count - count);
1909                 if (retval)
1910                         return retval;
1911                 count = (MTBSFM == mt_op ? 1 : -1);
1912                 return idetape_space_over_filemarks(drive, MTFSF, count);
1913         default:
1914                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1915                                 mt_op);
1916                 return -EIO;
1917         }
1918 }
1919
1920 /*
1921  * Our character device read / write functions.
1922  *
1923  * The tape is optimized to maximize throughput when it is transferring an
1924  * integral number of the "continuous transfer limit", which is a parameter of
1925  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1926  *
1927  * As of version 1.3 of the driver, the character device provides an abstract
1928  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1929  * same backup/restore procedure is supported. The driver will internally
1930  * convert the requests to the recommended transfer unit, so that an unmatch
1931  * between the user's block size to the recommended size will only result in a
1932  * (slightly) increased driver overhead, but will no longer hit performance.
1933  * This is not applicable to Onstream.
1934  */
1935 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1936                                    size_t count, loff_t *ppos)
1937 {
1938         struct ide_tape_obj *tape = ide_tape_f(file);
1939         ide_drive_t *drive = tape->drive;
1940         ssize_t bytes_read, temp, actually_read = 0, rc;
1941         ssize_t ret = 0;
1942         u16 ctl = *(u16 *)&tape->caps[12];
1943
1944         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1945
1946         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1947                 if (test_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags))
1948                         if (count > tape->blk_size &&
1949                             (count % tape->blk_size) == 0)
1950                                 tape->user_bs_factor = count / tape->blk_size;
1951         }
1952         rc = idetape_init_read(drive);
1953         if (rc < 0)
1954                 return rc;
1955         if (count == 0)
1956                 return (0);
1957         if (tape->merge_bh_size) {
1958                 actually_read = min((unsigned int)(tape->merge_bh_size),
1959                                     (unsigned int)count);
1960                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1961                         ret = -EFAULT;
1962                 buf += actually_read;
1963                 tape->merge_bh_size -= actually_read;
1964                 count -= actually_read;
1965         }
1966         while (count >= tape->buffer_size) {
1967                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1968                 if (bytes_read <= 0)
1969                         goto finish;
1970                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1971                         ret = -EFAULT;
1972                 buf += bytes_read;
1973                 count -= bytes_read;
1974                 actually_read += bytes_read;
1975         }
1976         if (count) {
1977                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1978                 if (bytes_read <= 0)
1979                         goto finish;
1980                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1981                 if (idetape_copy_stage_to_user(tape, buf, temp))
1982                         ret = -EFAULT;
1983                 actually_read += temp;
1984                 tape->merge_bh_size = bytes_read-temp;
1985         }
1986 finish:
1987         if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
1988                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1989
1990                 idetape_space_over_filemarks(drive, MTFSF, 1);
1991                 return 0;
1992         }
1993
1994         return ret ? ret : actually_read;
1995 }
1996
1997 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1998                                      size_t count, loff_t *ppos)
1999 {
2000         struct ide_tape_obj *tape = ide_tape_f(file);
2001         ide_drive_t *drive = tape->drive;
2002         ssize_t actually_written = 0;
2003         ssize_t ret = 0;
2004         u16 ctl = *(u16 *)&tape->caps[12];
2005
2006         /* The drive is write protected. */
2007         if (tape->write_prot)
2008                 return -EACCES;
2009
2010         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2011
2012         /* Initialize write operation */
2013         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2014                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2015                         ide_tape_discard_merge_buffer(drive, 1);
2016                 if (tape->merge_bh || tape->merge_bh_size) {
2017                         printk(KERN_ERR "ide-tape: merge_bh_size "
2018                                 "should be 0 now\n");
2019                         tape->merge_bh_size = 0;
2020                 }
2021                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
2022                 if (!tape->merge_bh)
2023                         return -ENOMEM;
2024                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
2025                 idetape_init_merge_buffer(tape);
2026
2027                 /*
2028                  * Issue a write 0 command to ensure that DSC handshake is
2029                  * switched from completion mode to buffer available mode. No
2030                  * point in issuing this if DSC overlap isn't supported, some
2031                  * drives (Seagate STT3401A) will return an error.
2032                  */
2033                 if (drive->dsc_overlap) {
2034                         ssize_t retval = idetape_queue_rw_tail(drive,
2035                                                         REQ_IDETAPE_WRITE, 0,
2036                                                         tape->merge_bh);
2037                         if (retval < 0) {
2038                                 ide_tape_kfree_buffer(tape);
2039                                 tape->merge_bh = NULL;
2040                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2041                                 return retval;
2042                         }
2043                 }
2044         }
2045         if (count == 0)
2046                 return (0);
2047         if (tape->merge_bh_size) {
2048                 if (tape->merge_bh_size >= tape->buffer_size) {
2049                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
2050                         tape->merge_bh_size = 0;
2051                 }
2052                 actually_written = min((unsigned int)
2053                                 (tape->buffer_size - tape->merge_bh_size),
2054                                 (unsigned int)count);
2055                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
2056                                 ret = -EFAULT;
2057                 buf += actually_written;
2058                 tape->merge_bh_size += actually_written;
2059                 count -= actually_written;
2060
2061                 if (tape->merge_bh_size == tape->buffer_size) {
2062                         ssize_t retval;
2063                         tape->merge_bh_size = 0;
2064                         retval = idetape_add_chrdev_write_request(drive, ctl);
2065                         if (retval <= 0)
2066                                 return (retval);
2067                 }
2068         }
2069         while (count >= tape->buffer_size) {
2070                 ssize_t retval;
2071                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
2072                         ret = -EFAULT;
2073                 buf += tape->buffer_size;
2074                 count -= tape->buffer_size;
2075                 retval = idetape_add_chrdev_write_request(drive, ctl);
2076                 actually_written += tape->buffer_size;
2077                 if (retval <= 0)
2078                         return (retval);
2079         }
2080         if (count) {
2081                 actually_written += count;
2082                 if (idetape_copy_stage_from_user(tape, buf, count))
2083                         ret = -EFAULT;
2084                 tape->merge_bh_size += count;
2085         }
2086         return ret ? ret : actually_written;
2087 }
2088
2089 static int idetape_write_filemark(ide_drive_t *drive)
2090 {
2091         struct ide_atapi_pc pc;
2092
2093         /* Write a filemark */
2094         idetape_create_write_filemark_cmd(drive, &pc, 1);
2095         if (idetape_queue_pc_tail(drive, &pc)) {
2096                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
2097                 return -EIO;
2098         }
2099         return 0;
2100 }
2101
2102 /*
2103  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
2104  * requested.
2105  *
2106  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
2107  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
2108  * usually not supported.
2109  *
2110  * The following commands are currently not supported:
2111  *
2112  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
2113  * MT_ST_WRITE_THRESHOLD.
2114  */
2115 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
2116 {
2117         idetape_tape_t *tape = drive->driver_data;
2118         struct ide_atapi_pc pc;
2119         int i, retval;
2120
2121         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
2122                         mt_op, mt_count);
2123
2124         switch (mt_op) {
2125         case MTFSF:
2126         case MTFSFM:
2127         case MTBSF:
2128         case MTBSFM:
2129                 if (!mt_count)
2130                         return 0;
2131                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
2132         default:
2133                 break;
2134         }
2135
2136         switch (mt_op) {
2137         case MTWEOF:
2138                 if (tape->write_prot)
2139                         return -EACCES;
2140                 ide_tape_discard_merge_buffer(drive, 1);
2141                 for (i = 0; i < mt_count; i++) {
2142                         retval = idetape_write_filemark(drive);
2143                         if (retval)
2144                                 return retval;
2145                 }
2146                 return 0;
2147         case MTREW:
2148                 ide_tape_discard_merge_buffer(drive, 0);
2149                 if (idetape_rewind_tape(drive))
2150                         return -EIO;
2151                 return 0;
2152         case MTLOAD:
2153                 ide_tape_discard_merge_buffer(drive, 0);
2154                 idetape_create_load_unload_cmd(drive, &pc,
2155                                                IDETAPE_LU_LOAD_MASK);
2156                 return idetape_queue_pc_tail(drive, &pc);
2157         case MTUNLOAD:
2158         case MTOFFL:
2159                 /*
2160                  * If door is locked, attempt to unlock before
2161                  * attempting to eject.
2162                  */
2163                 if (tape->door_locked) {
2164                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2165                                 if (!idetape_queue_pc_tail(drive, &pc))
2166                                         tape->door_locked = DOOR_UNLOCKED;
2167                 }
2168                 ide_tape_discard_merge_buffer(drive, 0);
2169                 idetape_create_load_unload_cmd(drive, &pc,
2170                                               !IDETAPE_LU_LOAD_MASK);
2171                 retval = idetape_queue_pc_tail(drive, &pc);
2172                 if (!retval)
2173                         clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
2174                 return retval;
2175         case MTNOP:
2176                 ide_tape_discard_merge_buffer(drive, 0);
2177                 return idetape_flush_tape_buffers(drive);
2178         case MTRETEN:
2179                 ide_tape_discard_merge_buffer(drive, 0);
2180                 idetape_create_load_unload_cmd(drive, &pc,
2181                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2182                 return idetape_queue_pc_tail(drive, &pc);
2183         case MTEOM:
2184                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
2185                 return idetape_queue_pc_tail(drive, &pc);
2186         case MTERASE:
2187                 (void)idetape_rewind_tape(drive);
2188                 idetape_create_erase_cmd(&pc);
2189                 return idetape_queue_pc_tail(drive, &pc);
2190         case MTSETBLK:
2191                 if (mt_count) {
2192                         if (mt_count < tape->blk_size ||
2193                             mt_count % tape->blk_size)
2194                                 return -EIO;
2195                         tape->user_bs_factor = mt_count / tape->blk_size;
2196                         clear_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2197                 } else
2198                         set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2199                 return 0;
2200         case MTSEEK:
2201                 ide_tape_discard_merge_buffer(drive, 0);
2202                 return idetape_position_tape(drive,
2203                         mt_count * tape->user_bs_factor, tape->partition, 0);
2204         case MTSETPART:
2205                 ide_tape_discard_merge_buffer(drive, 0);
2206                 return idetape_position_tape(drive, 0, mt_count, 0);
2207         case MTFSR:
2208         case MTBSR:
2209         case MTLOCK:
2210                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
2211                         return 0;
2212                 retval = idetape_queue_pc_tail(drive, &pc);
2213                 if (retval)
2214                         return retval;
2215                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
2216                 return 0;
2217         case MTUNLOCK:
2218                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
2219                         return 0;
2220                 retval = idetape_queue_pc_tail(drive, &pc);
2221                 if (retval)
2222                         return retval;
2223                 tape->door_locked = DOOR_UNLOCKED;
2224                 return 0;
2225         default:
2226                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2227                                 mt_op);
2228                 return -EIO;
2229         }
2230 }
2231
2232 /*
2233  * Our character device ioctls. General mtio.h magnetic io commands are
2234  * supported here, and not in the corresponding block interface. Our own
2235  * ide-tape ioctls are supported on both interfaces.
2236  */
2237 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
2238                                 unsigned int cmd, unsigned long arg)
2239 {
2240         struct ide_tape_obj *tape = ide_tape_f(file);
2241         ide_drive_t *drive = tape->drive;
2242         struct mtop mtop;
2243         struct mtget mtget;
2244         struct mtpos mtpos;
2245         int block_offset = 0, position = tape->first_frame;
2246         void __user *argp = (void __user *)arg;
2247
2248         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
2249
2250         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2251                 ide_tape_flush_merge_buffer(drive);
2252                 idetape_flush_tape_buffers(drive);
2253         }
2254         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
2255                 block_offset = tape->merge_bh_size /
2256                         (tape->blk_size * tape->user_bs_factor);
2257                 position = idetape_read_position(drive);
2258                 if (position < 0)
2259                         return -EIO;
2260         }
2261         switch (cmd) {
2262         case MTIOCTOP:
2263                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
2264                         return -EFAULT;
2265                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
2266         case MTIOCGET:
2267                 memset(&mtget, 0, sizeof(struct mtget));
2268                 mtget.mt_type = MT_ISSCSI2;
2269                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
2270                 mtget.mt_dsreg =
2271                         ((tape->blk_size * tape->user_bs_factor)
2272                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
2273
2274                 if (tape->drv_write_prot)
2275                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
2276
2277                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
2278                         return -EFAULT;
2279                 return 0;
2280         case MTIOCPOS:
2281                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
2282                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
2283                         return -EFAULT;
2284                 return 0;
2285         default:
2286                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2287                         ide_tape_discard_merge_buffer(drive, 1);
2288                 return idetape_blkdev_ioctl(drive, cmd, arg);
2289         }
2290 }
2291
2292 /*
2293  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
2294  * block size with the reported value.
2295  */
2296 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
2297 {
2298         idetape_tape_t *tape = drive->driver_data;
2299         struct ide_atapi_pc pc;
2300
2301         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
2302         if (idetape_queue_pc_tail(drive, &pc)) {
2303                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
2304                 if (tape->blk_size == 0) {
2305                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
2306                                             "block size, assuming 32k\n");
2307                         tape->blk_size = 32768;
2308                 }
2309                 return;
2310         }
2311         tape->blk_size = (pc.buf[4 + 5] << 16) +
2312                                 (pc.buf[4 + 6] << 8)  +
2313                                  pc.buf[4 + 7];
2314         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
2315 }
2316
2317 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
2318 {
2319         unsigned int minor = iminor(inode), i = minor & ~0xc0;
2320         ide_drive_t *drive;
2321         idetape_tape_t *tape;
2322         struct ide_atapi_pc pc;
2323         int retval;
2324
2325         if (i >= MAX_HWIFS * MAX_DRIVES)
2326                 return -ENXIO;
2327
2328         tape = ide_tape_chrdev_get(i);
2329         if (!tape)
2330                 return -ENXIO;
2331
2332         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2333
2334         /*
2335          * We really want to do nonseekable_open(inode, filp); here, but some
2336          * versions of tar incorrectly call lseek on tapes and bail out if that
2337          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
2338          */
2339         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
2340
2341         drive = tape->drive;
2342
2343         filp->private_data = tape;
2344
2345         if (test_and_set_bit(IDETAPE_FLAG_BUSY, &tape->flags)) {
2346                 retval = -EBUSY;
2347                 goto out_put_tape;
2348         }
2349
2350         retval = idetape_wait_ready(drive, 60 * HZ);
2351         if (retval) {
2352                 clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2353                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
2354                 goto out_put_tape;
2355         }
2356
2357         idetape_read_position(drive);
2358         if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
2359                 (void)idetape_rewind_tape(drive);
2360
2361         /* Read block size and write protect status from drive. */
2362         ide_tape_get_bsize_from_bdesc(drive);
2363
2364         /* Set write protect flag if device is opened as read-only. */
2365         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
2366                 tape->write_prot = 1;
2367         else
2368                 tape->write_prot = tape->drv_write_prot;
2369
2370         /* Make sure drive isn't write protected if user wants to write. */
2371         if (tape->write_prot) {
2372                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
2373                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
2374                         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2375                         retval = -EROFS;
2376                         goto out_put_tape;
2377                 }
2378         }
2379
2380         /* Lock the tape drive door so user can't eject. */
2381         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2382                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
2383                         if (!idetape_queue_pc_tail(drive, &pc)) {
2384                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2385                                         tape->door_locked = DOOR_LOCKED;
2386                         }
2387                 }
2388         }
2389         return 0;
2390
2391 out_put_tape:
2392         ide_tape_put(tape);
2393         return retval;
2394 }
2395
2396 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2397 {
2398         idetape_tape_t *tape = drive->driver_data;
2399
2400         ide_tape_flush_merge_buffer(drive);
2401         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2402         if (tape->merge_bh != NULL) {
2403                 idetape_pad_zeros(drive, tape->blk_size *
2404                                 (tape->user_bs_factor - 1));
2405                 ide_tape_kfree_buffer(tape);
2406                 tape->merge_bh = NULL;
2407         }
2408         idetape_write_filemark(drive);
2409         idetape_flush_tape_buffers(drive);
2410         idetape_flush_tape_buffers(drive);
2411 }
2412
2413 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2414 {
2415         struct ide_tape_obj *tape = ide_tape_f(filp);
2416         ide_drive_t *drive = tape->drive;
2417         struct ide_atapi_pc pc;
2418         unsigned int minor = iminor(inode);
2419
2420         lock_kernel();
2421         tape = drive->driver_data;
2422
2423         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2424
2425         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2426                 idetape_write_release(drive, minor);
2427         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2428                 if (minor < 128)
2429                         ide_tape_discard_merge_buffer(drive, 1);
2430         }
2431
2432         if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
2433                 (void) idetape_rewind_tape(drive);
2434         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2435                 if (tape->door_locked == DOOR_LOCKED) {
2436                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
2437                                 if (!idetape_queue_pc_tail(drive, &pc))
2438                                         tape->door_locked = DOOR_UNLOCKED;
2439                         }
2440                 }
2441         }
2442         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2443         ide_tape_put(tape);
2444         unlock_kernel();
2445         return 0;
2446 }
2447
2448 /*
2449  * check the contents of the ATAPI IDENTIFY command results. We return:
2450  *
2451  * 1 - If the tape can be supported by us, based on the information we have so
2452  * far.
2453  *
2454  * 0 - If this tape driver is not currently supported by us.
2455  */
2456 static int idetape_identify_device(ide_drive_t *drive)
2457 {
2458         u8 gcw[2], protocol, device_type, removable, packet_size;
2459
2460         if (drive->id_read == 0)
2461                 return 1;
2462
2463         *((unsigned short *) &gcw) = drive->id->config;
2464
2465         protocol        =   (gcw[1] & 0xC0) >> 6;
2466         device_type     =    gcw[1] & 0x1F;
2467         removable       = !!(gcw[0] & 0x80);
2468         packet_size     =    gcw[0] & 0x3;
2469
2470         /* Check that we can support this device */
2471         if (protocol != 2)
2472                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
2473                                 protocol);
2474         else if (device_type != 1)
2475                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
2476                                 "to tape\n", device_type);
2477         else if (!removable)
2478                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
2479         else if (packet_size != 0) {
2480                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
2481                                 " bytes\n", packet_size);
2482         } else
2483                 return 1;
2484         return 0;
2485 }
2486
2487 static void idetape_get_inquiry_results(ide_drive_t *drive)
2488 {
2489         idetape_tape_t *tape = drive->driver_data;
2490         struct ide_atapi_pc pc;
2491         char fw_rev[6], vendor_id[10], product_id[18];
2492
2493         idetape_create_inquiry_cmd(&pc);
2494         if (idetape_queue_pc_tail(drive, &pc)) {
2495                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2496                                 tape->name);
2497                 return;
2498         }
2499         memcpy(vendor_id, &pc.buf[8], 8);
2500         memcpy(product_id, &pc.buf[16], 16);
2501         memcpy(fw_rev, &pc.buf[32], 4);
2502
2503         ide_fixstring(vendor_id, 10, 0);
2504         ide_fixstring(product_id, 18, 0);
2505         ide_fixstring(fw_rev, 6, 0);
2506
2507         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
2508                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2509 }
2510
2511 /*
2512  * Ask the tape about its various parameters. In particular, we will adjust our
2513  * data transfer buffer size to the recommended value as returned by the tape.
2514  */
2515 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2516 {
2517         idetape_tape_t *tape = drive->driver_data;
2518         struct ide_atapi_pc pc;
2519         u8 *caps;
2520         u8 speed, max_speed;
2521
2522         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2523         if (idetape_queue_pc_tail(drive, &pc)) {
2524                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2525                                 " some default values\n");
2526                 tape->blk_size = 512;
2527                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2528                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2529                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2530                 return;
2531         }
2532         caps = pc.buf + 4 + pc.buf[3];
2533
2534         /* convert to host order and save for later use */
2535         speed = be16_to_cpu(*(u16 *)&caps[14]);
2536         max_speed = be16_to_cpu(*(u16 *)&caps[8]);
2537
2538         put_unaligned(max_speed, (u16 *)&caps[8]);
2539         put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
2540         put_unaligned(speed, (u16 *)&caps[14]);
2541         put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
2542
2543         if (!speed) {
2544                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2545                                 "(assuming 650KB/sec)\n", drive->name);
2546                 put_unaligned(650, (u16 *)&caps[14]);
2547         }
2548         if (!max_speed) {
2549                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2550                                 "(assuming 650KB/sec)\n", drive->name);
2551                 put_unaligned(650, (u16 *)&caps[8]);
2552         }
2553
2554         memcpy(&tape->caps, caps, 20);
2555         if (caps[7] & 0x02)
2556                 tape->blk_size = 512;
2557         else if (caps[7] & 0x04)
2558                 tape->blk_size = 1024;
2559 }
2560
2561 #ifdef CONFIG_IDE_PROC_FS
2562 static void idetape_add_settings(ide_drive_t *drive)
2563 {
2564         idetape_tape_t *tape = drive->driver_data;
2565
2566         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2567                         1, 2, (u16 *)&tape->caps[16], NULL);
2568         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2569                         1, 1, (u16 *)&tape->caps[14], NULL);
2570         ide_add_setting(drive, "buffer_size", SETTING_READ, TYPE_INT, 0, 0xffff,
2571                         1, 1024, &tape->buffer_size, NULL);
2572         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
2573                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
2574                         NULL);
2575         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
2576                         1, &drive->dsc_overlap, NULL);
2577         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
2578                         1, 1, &tape->avg_speed, NULL);
2579         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
2580                         1, &tape->debug_mask, NULL);
2581 }
2582 #else
2583 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
2584 #endif
2585
2586 /*
2587  * The function below is called to:
2588  *
2589  * 1. Initialize our various state variables.
2590  * 2. Ask the tape for its capabilities.
2591  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2592  * is chosen based on the recommendation which we received in step 2.
2593  *
2594  * Note that at this point ide.c already assigned us an irq, so that we can
2595  * queue requests here and wait for their completion.
2596  */
2597 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2598 {
2599         unsigned long t;
2600         int speed;
2601         int buffer_size;
2602         u8 gcw[2];
2603         u16 *ctl = (u16 *)&tape->caps[12];
2604
2605         spin_lock_init(&tape->lock);
2606         drive->dsc_overlap = 1;
2607         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2608                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2609                                  tape->name);
2610                 drive->dsc_overlap = 0;
2611         }
2612         /* Seagate Travan drives do not support DSC overlap. */
2613         if (strstr(drive->id->model, "Seagate STT3401"))
2614                 drive->dsc_overlap = 0;
2615         tape->minor = minor;
2616         tape->name[0] = 'h';
2617         tape->name[1] = 't';
2618         tape->name[2] = '0' + minor;
2619         tape->chrdev_dir = IDETAPE_DIR_NONE;
2620         tape->pc = tape->pc_stack;
2621         *((unsigned short *) &gcw) = drive->id->config;
2622
2623         /* Command packet DRQ type */
2624         if (((gcw[0] & 0x60) >> 5) == 1)
2625                 set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
2626
2627         idetape_get_inquiry_results(drive);
2628         idetape_get_mode_sense_results(drive);
2629         ide_tape_get_bsize_from_bdesc(drive);
2630         tape->user_bs_factor = 1;
2631         tape->buffer_size = *ctl * tape->blk_size;
2632         while (tape->buffer_size > 0xffff) {
2633                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2634                 *ctl /= 2;
2635                 tape->buffer_size = *ctl * tape->blk_size;
2636         }
2637         buffer_size = tape->buffer_size;
2638         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2639         if (buffer_size % PAGE_SIZE) {
2640                 tape->pages_per_buffer++;
2641                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2642         }
2643
2644         /* select the "best" DSC read/write polling freq */
2645         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2646
2647         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2648
2649         /*
2650          * Ensure that the number we got makes sense; limit it within
2651          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2652          */
2653         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2654                                          IDETAPE_DSC_RW_MAX);
2655         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2656                 "%lums tDSC%s\n",
2657                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2658                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2659                 tape->buffer_size / 1024,
2660                 tape->best_dsc_rw_freq * 1000 / HZ,
2661                 drive->using_dma ? ", DMA":"");
2662
2663         idetape_add_settings(drive);
2664 }
2665
2666 static void ide_tape_remove(ide_drive_t *drive)
2667 {
2668         idetape_tape_t *tape = drive->driver_data;
2669
2670         ide_proc_unregister_driver(drive, tape->driver);
2671
2672         ide_unregister_region(tape->disk);
2673
2674         ide_tape_put(tape);
2675 }
2676
2677 static void ide_tape_release(struct kref *kref)
2678 {
2679         struct ide_tape_obj *tape = to_ide_tape(kref);
2680         ide_drive_t *drive = tape->drive;
2681         struct gendisk *g = tape->disk;
2682
2683         BUG_ON(tape->merge_bh_size);
2684
2685         drive->dsc_overlap = 0;
2686         drive->driver_data = NULL;
2687         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2688         device_destroy(idetape_sysfs_class,
2689                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2690         idetape_devs[tape->minor] = NULL;
2691         g->private_data = NULL;
2692         put_disk(g);
2693         kfree(tape);
2694 }
2695
2696 #ifdef CONFIG_IDE_PROC_FS
2697 static int proc_idetape_read_name
2698         (char *page, char **start, off_t off, int count, int *eof, void *data)
2699 {
2700         ide_drive_t     *drive = (ide_drive_t *) data;
2701         idetape_tape_t  *tape = drive->driver_data;
2702         char            *out = page;
2703         int             len;
2704
2705         len = sprintf(out, "%s\n", tape->name);
2706         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2707 }
2708
2709 static ide_proc_entry_t idetape_proc[] = {
2710         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2711         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2712         { NULL, 0, NULL, NULL }
2713 };
2714 #endif
2715
2716 static int ide_tape_probe(ide_drive_t *);
2717
2718 static ide_driver_t idetape_driver = {
2719         .gen_driver = {
2720                 .owner          = THIS_MODULE,
2721                 .name           = "ide-tape",
2722                 .bus            = &ide_bus_type,
2723         },
2724         .probe                  = ide_tape_probe,
2725         .remove                 = ide_tape_remove,
2726         .version                = IDETAPE_VERSION,
2727         .media                  = ide_tape,
2728         .supports_dsc_overlap   = 1,
2729         .do_request             = idetape_do_request,
2730         .end_request            = idetape_end_request,
2731         .error                  = __ide_error,
2732         .abort                  = __ide_abort,
2733 #ifdef CONFIG_IDE_PROC_FS
2734         .proc                   = idetape_proc,
2735 #endif
2736 };
2737
2738 /* Our character device supporting functions, passed to register_chrdev. */
2739 static const struct file_operations idetape_fops = {
2740         .owner          = THIS_MODULE,
2741         .read           = idetape_chrdev_read,
2742         .write          = idetape_chrdev_write,
2743         .ioctl          = idetape_chrdev_ioctl,
2744         .open           = idetape_chrdev_open,
2745         .release        = idetape_chrdev_release,
2746 };
2747
2748 static int idetape_open(struct inode *inode, struct file *filp)
2749 {
2750         struct gendisk *disk = inode->i_bdev->bd_disk;
2751         struct ide_tape_obj *tape;
2752
2753         tape = ide_tape_get(disk);
2754         if (!tape)
2755                 return -ENXIO;
2756
2757         return 0;
2758 }
2759
2760 static int idetape_release(struct inode *inode, struct file *filp)
2761 {
2762         struct gendisk *disk = inode->i_bdev->bd_disk;
2763         struct ide_tape_obj *tape = ide_tape_g(disk);
2764
2765         ide_tape_put(tape);
2766
2767         return 0;
2768 }
2769
2770 static int idetape_ioctl(struct inode *inode, struct file *file,
2771                         unsigned int cmd, unsigned long arg)
2772 {
2773         struct block_device *bdev = inode->i_bdev;
2774         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2775         ide_drive_t *drive = tape->drive;
2776         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2777         if (err == -EINVAL)
2778                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2779         return err;
2780 }
2781
2782 static struct block_device_operations idetape_block_ops = {
2783         .owner          = THIS_MODULE,
2784         .open           = idetape_open,
2785         .release        = idetape_release,
2786         .ioctl          = idetape_ioctl,
2787 };
2788
2789 static int ide_tape_probe(ide_drive_t *drive)
2790 {
2791         idetape_tape_t *tape;
2792         struct gendisk *g;
2793         int minor;
2794
2795         if (!strstr("ide-tape", drive->driver_req))
2796                 goto failed;
2797         if (!drive->present)
2798                 goto failed;
2799         if (drive->media != ide_tape)
2800                 goto failed;
2801         if (!idetape_identify_device(drive)) {
2802                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2803                                 " the driver\n", drive->name);
2804                 goto failed;
2805         }
2806         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2807         if (tape == NULL) {
2808                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2809                                 drive->name);
2810                 goto failed;
2811         }
2812
2813         g = alloc_disk(1 << PARTN_BITS);
2814         if (!g)
2815                 goto out_free_tape;
2816
2817         ide_init_disk(g, drive);
2818
2819         ide_proc_register_driver(drive, &idetape_driver);
2820
2821         kref_init(&tape->kref);
2822
2823         tape->drive = drive;
2824         tape->driver = &idetape_driver;
2825         tape->disk = g;
2826
2827         g->private_data = &tape->driver;
2828
2829         drive->driver_data = tape;
2830
2831         mutex_lock(&idetape_ref_mutex);
2832         for (minor = 0; idetape_devs[minor]; minor++)
2833                 ;
2834         idetape_devs[minor] = tape;
2835         mutex_unlock(&idetape_ref_mutex);
2836
2837         idetape_setup(drive, tape, minor);
2838
2839         device_create(idetape_sysfs_class, &drive->gendev,
2840                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
2841         device_create(idetape_sysfs_class, &drive->gendev,
2842                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
2843
2844         g->fops = &idetape_block_ops;
2845         ide_register_region(g);
2846
2847         return 0;
2848
2849 out_free_tape:
2850         kfree(tape);
2851 failed:
2852         return -ENODEV;
2853 }
2854
2855 static void __exit idetape_exit(void)
2856 {
2857         driver_unregister(&idetape_driver.gen_driver);
2858         class_destroy(idetape_sysfs_class);
2859         unregister_chrdev(IDETAPE_MAJOR, "ht");
2860 }
2861
2862 static int __init idetape_init(void)
2863 {
2864         int error = 1;
2865         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2866         if (IS_ERR(idetape_sysfs_class)) {
2867                 idetape_sysfs_class = NULL;
2868                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2869                 error = -EBUSY;
2870                 goto out;
2871         }
2872
2873         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2874                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2875                                 " interface\n");
2876                 error = -EBUSY;
2877                 goto out_free_class;
2878         }
2879
2880         error = driver_register(&idetape_driver.gen_driver);
2881         if (error)
2882                 goto out_free_driver;
2883
2884         return 0;
2885
2886 out_free_driver:
2887         driver_unregister(&idetape_driver.gen_driver);
2888 out_free_class:
2889         class_destroy(idetape_sysfs_class);
2890 out:
2891         return error;
2892 }
2893
2894 MODULE_ALIAS("ide:*m-tape*");
2895 module_init(idetape_init);
2896 module_exit(idetape_exit);
2897 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2898 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2899 MODULE_LICENSE("GPL");