ide: add ide_issue_pc() helper
[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         idetape_tape_t *tape = drive->driver_data;
962
963         if (tape->pc->c[0] == REQUEST_SENSE &&
964             pc->c[0] == REQUEST_SENSE) {
965                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
966                         "Two request sense in serial were issued\n");
967         }
968
969         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
970                 tape->failed_pc = pc;
971         /* Set the current packet command */
972         tape->pc = pc;
973
974         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
975                 (pc->flags & PC_FLAG_ABORT)) {
976                 /*
977                  * We will "abort" retrying a packet command in case legitimate
978                  * error code was received (crossing a filemark, or end of the
979                  * media, for example).
980                  */
981                 if (!(pc->flags & PC_FLAG_ABORT)) {
982                         if (!(pc->c[0] == TEST_UNIT_READY &&
983                               tape->sense_key == 2 && tape->asc == 4 &&
984                              (tape->ascq == 1 || tape->ascq == 8))) {
985                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
986                                                 "pc = %2x, key = %2x, "
987                                                 "asc = %2x, ascq = %2x\n",
988                                                 tape->name, pc->c[0],
989                                                 tape->sense_key, tape->asc,
990                                                 tape->ascq);
991                         }
992                         /* Giving up */
993                         pc->error = IDETAPE_ERROR_GENERAL;
994                 }
995                 tape->failed_pc = NULL;
996                 pc->callback(drive);
997                 return ide_stopped;
998         }
999         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
1000
1001         pc->retries++;
1002
1003         return ide_issue_pc(drive, pc, idetape_transfer_pc,
1004                             IDETAPE_WAIT_CMD, NULL);
1005 }
1006
1007 /* A mode sense command is used to "sense" tape parameters. */
1008 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
1009 {
1010         idetape_init_pc(pc);
1011         pc->c[0] = MODE_SENSE;
1012         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1013                 /* DBD = 1 - Don't return block descriptors */
1014                 pc->c[1] = 8;
1015         pc->c[2] = page_code;
1016         /*
1017          * Changed pc->c[3] to 0 (255 will at best return unused info).
1018          *
1019          * For SCSI this byte is defined as subpage instead of high byte
1020          * of length and some IDE drives seem to interpret it this way
1021          * and return an error when 255 is used.
1022          */
1023         pc->c[3] = 0;
1024         /* We will just discard data in that case */
1025         pc->c[4] = 255;
1026         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1027                 pc->req_xfer = 12;
1028         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
1029                 pc->req_xfer = 24;
1030         else
1031                 pc->req_xfer = 50;
1032 }
1033
1034 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
1035 {
1036         idetape_tape_t *tape = drive->driver_data;
1037         struct ide_atapi_pc *pc = tape->pc;
1038         u8 stat;
1039
1040         stat = ide_read_status(drive);
1041
1042         if (stat & SEEK_STAT) {
1043                 if (stat & ERR_STAT) {
1044                         /* Error detected */
1045                         if (pc->c[0] != TEST_UNIT_READY)
1046                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
1047                                                 tape->name);
1048                         /* Retry operation */
1049                         idetape_retry_pc(drive);
1050                         return ide_stopped;
1051                 }
1052                 pc->error = 0;
1053                 if (tape->failed_pc == pc)
1054                         tape->failed_pc = NULL;
1055         } else {
1056                 pc->error = IDETAPE_ERROR_GENERAL;
1057                 tape->failed_pc = NULL;
1058         }
1059         pc->callback(drive);
1060         return ide_stopped;
1061 }
1062
1063 static void idetape_create_read_cmd(idetape_tape_t *tape,
1064                 struct ide_atapi_pc *pc,
1065                 unsigned int length, struct idetape_bh *bh)
1066 {
1067         idetape_init_pc(pc);
1068         pc->c[0] = READ_6;
1069         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1070         pc->c[1] = 1;
1071         pc->bh = bh;
1072         atomic_set(&bh->b_count, 0);
1073         pc->buf = NULL;
1074         pc->buf_size = length * tape->blk_size;
1075         pc->req_xfer = pc->buf_size;
1076         if (pc->req_xfer == tape->buffer_size)
1077                 pc->flags |= PC_FLAG_DMA_OK;
1078 }
1079
1080 static void idetape_create_write_cmd(idetape_tape_t *tape,
1081                 struct ide_atapi_pc *pc,
1082                 unsigned int length, struct idetape_bh *bh)
1083 {
1084         idetape_init_pc(pc);
1085         pc->c[0] = WRITE_6;
1086         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1087         pc->c[1] = 1;
1088         pc->flags |= PC_FLAG_WRITING;
1089         pc->bh = bh;
1090         pc->b_data = bh->b_data;
1091         pc->b_count = atomic_read(&bh->b_count);
1092         pc->buf = NULL;
1093         pc->buf_size = length * tape->blk_size;
1094         pc->req_xfer = pc->buf_size;
1095         if (pc->req_xfer == tape->buffer_size)
1096                 pc->flags |= PC_FLAG_DMA_OK;
1097 }
1098
1099 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1100                                           struct request *rq, sector_t block)
1101 {
1102         idetape_tape_t *tape = drive->driver_data;
1103         struct ide_atapi_pc *pc = NULL;
1104         struct request *postponed_rq = tape->postponed_rq;
1105         u8 stat;
1106
1107         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
1108                         " current_nr_sectors: %d\n",
1109                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1110
1111         if (!blk_special_request(rq)) {
1112                 /* We do not support buffer cache originated requests. */
1113                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1114                         "request queue (%d)\n", drive->name, rq->cmd_type);
1115                 ide_end_request(drive, 0, 0);
1116                 return ide_stopped;
1117         }
1118
1119         /* Retry a failed packet command */
1120         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE) {
1121                 pc = tape->failed_pc;
1122                 goto out;
1123         }
1124
1125         if (postponed_rq != NULL)
1126                 if (rq != postponed_rq) {
1127                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1128                                         "Two DSC requests were queued\n");
1129                         idetape_end_request(drive, 0, 0);
1130                         return ide_stopped;
1131                 }
1132
1133         tape->postponed_rq = NULL;
1134
1135         /*
1136          * If the tape is still busy, postpone our request and service
1137          * the other device meanwhile.
1138          */
1139         stat = ide_read_status(drive);
1140
1141         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
1142                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1143
1144         if (drive->post_reset == 1) {
1145                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1146                 drive->post_reset = 0;
1147         }
1148
1149         if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&
1150             (stat & SEEK_STAT) == 0) {
1151                 if (postponed_rq == NULL) {
1152                         tape->dsc_polling_start = jiffies;
1153                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1154                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1155                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1156                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1157                                 tape->name);
1158                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1159                                 idetape_media_access_finished(drive);
1160                                 return ide_stopped;
1161                         } else {
1162                                 return ide_do_reset(drive);
1163                         }
1164                 } else if (time_after(jiffies,
1165                                         tape->dsc_polling_start +
1166                                         IDETAPE_DSC_MA_THRESHOLD))
1167                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1168                 idetape_postpone_request(drive);
1169                 return ide_stopped;
1170         }
1171         if (rq->cmd[0] & REQ_IDETAPE_READ) {
1172                 pc = idetape_next_pc_storage(drive);
1173                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
1174                                         (struct idetape_bh *)rq->special);
1175                 goto out;
1176         }
1177         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1178                 pc = idetape_next_pc_storage(drive);
1179                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
1180                                          (struct idetape_bh *)rq->special);
1181                 goto out;
1182         }
1183         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
1184                 pc = (struct ide_atapi_pc *) rq->buffer;
1185                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
1186                 rq->cmd[0] |= REQ_IDETAPE_PC2;
1187                 goto out;
1188         }
1189         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1190                 idetape_media_access_finished(drive);
1191                 return ide_stopped;
1192         }
1193         BUG();
1194 out:
1195         if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags))
1196                 pc->flags |= PC_FLAG_DRQ_INTERRUPT;
1197
1198         return idetape_issue_pc(drive, pc);
1199 }
1200
1201 /*
1202  * The function below uses __get_free_pages to allocate a data buffer of size
1203  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
1204  * much as possible.
1205  *
1206  * It returns a pointer to the newly allocated buffer, or NULL in case of
1207  * failure.
1208  */
1209 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
1210                                                   int full, int clear)
1211 {
1212         struct idetape_bh *prev_bh, *bh, *merge_bh;
1213         int pages = tape->pages_per_buffer;
1214         unsigned int order, b_allocd;
1215         char *b_data = NULL;
1216
1217         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1218         bh = merge_bh;
1219         if (bh == NULL)
1220                 goto abort;
1221
1222         order = fls(pages) - 1;
1223         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1224         if (!bh->b_data)
1225                 goto abort;
1226         b_allocd = (1 << order) * PAGE_SIZE;
1227         pages &= (order-1);
1228
1229         if (clear)
1230                 memset(bh->b_data, 0, b_allocd);
1231         bh->b_reqnext = NULL;
1232         bh->b_size = b_allocd;
1233         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1234
1235         while (pages) {
1236                 order = fls(pages) - 1;
1237                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1238                 if (!b_data)
1239                         goto abort;
1240                 b_allocd = (1 << order) * PAGE_SIZE;
1241
1242                 if (clear)
1243                         memset(b_data, 0, b_allocd);
1244
1245                 /* newly allocated page frames below buffer header or ...*/
1246                 if (bh->b_data == b_data + b_allocd) {
1247                         bh->b_size += b_allocd;
1248                         bh->b_data -= b_allocd;
1249                         if (full)
1250                                 atomic_add(b_allocd, &bh->b_count);
1251                         continue;
1252                 }
1253                 /* they are above the header */
1254                 if (b_data == bh->b_data + bh->b_size) {
1255                         bh->b_size += b_allocd;
1256                         if (full)
1257                                 atomic_add(b_allocd, &bh->b_count);
1258                         continue;
1259                 }
1260                 prev_bh = bh;
1261                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1262                 if (!bh) {
1263                         free_pages((unsigned long) b_data, order);
1264                         goto abort;
1265                 }
1266                 bh->b_reqnext = NULL;
1267                 bh->b_data = b_data;
1268                 bh->b_size = b_allocd;
1269                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1270                 prev_bh->b_reqnext = bh;
1271
1272                 pages &= (order-1);
1273         }
1274
1275         bh->b_size -= tape->excess_bh_size;
1276         if (full)
1277                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1278         return merge_bh;
1279 abort:
1280         ide_tape_kfree_buffer(tape);
1281         return NULL;
1282 }
1283
1284 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1285                                         const char __user *buf, int n)
1286 {
1287         struct idetape_bh *bh = tape->bh;
1288         int count;
1289         int ret = 0;
1290
1291         while (n) {
1292                 if (bh == NULL) {
1293                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1294                                         __func__);
1295                         return 1;
1296                 }
1297                 count = min((unsigned int)
1298                                 (bh->b_size - atomic_read(&bh->b_count)),
1299                                 (unsigned int)n);
1300                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1301                                 count))
1302                         ret = 1;
1303                 n -= count;
1304                 atomic_add(count, &bh->b_count);
1305                 buf += count;
1306                 if (atomic_read(&bh->b_count) == bh->b_size) {
1307                         bh = bh->b_reqnext;
1308                         if (bh)
1309                                 atomic_set(&bh->b_count, 0);
1310                 }
1311         }
1312         tape->bh = bh;
1313         return ret;
1314 }
1315
1316 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1317                                       int n)
1318 {
1319         struct idetape_bh *bh = tape->bh;
1320         int count;
1321         int ret = 0;
1322
1323         while (n) {
1324                 if (bh == NULL) {
1325                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1326                                         __func__);
1327                         return 1;
1328                 }
1329                 count = min(tape->b_count, n);
1330                 if  (copy_to_user(buf, tape->b_data, count))
1331                         ret = 1;
1332                 n -= count;
1333                 tape->b_data += count;
1334                 tape->b_count -= count;
1335                 buf += count;
1336                 if (!tape->b_count) {
1337                         bh = bh->b_reqnext;
1338                         tape->bh = bh;
1339                         if (bh) {
1340                                 tape->b_data = bh->b_data;
1341                                 tape->b_count = atomic_read(&bh->b_count);
1342                         }
1343                 }
1344         }
1345         return ret;
1346 }
1347
1348 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1349 {
1350         struct idetape_bh *bh = tape->merge_bh;
1351         tape->bh = tape->merge_bh;
1352
1353         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1354                 atomic_set(&bh->b_count, 0);
1355         else {
1356                 tape->b_data = bh->b_data;
1357                 tape->b_count = atomic_read(&bh->b_count);
1358         }
1359 }
1360
1361 /*
1362  * Write a filemark if write_filemark=1. Flush the device buffers without
1363  * writing a filemark otherwise.
1364  */
1365 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1366                 struct ide_atapi_pc *pc, int write_filemark)
1367 {
1368         idetape_init_pc(pc);
1369         pc->c[0] = WRITE_FILEMARKS;
1370         pc->c[4] = write_filemark;
1371         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1372 }
1373
1374 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1375 {
1376         idetape_init_pc(pc);
1377         pc->c[0] = TEST_UNIT_READY;
1378 }
1379
1380 /*
1381  * We add a special packet command request to the tail of the request queue, and
1382  * wait for it to be serviced. This is not to be called from within the request
1383  * handling part of the driver! We allocate here data on the stack and it is
1384  * valid until the request is finished. This is not the case for the bottom part
1385  * of the driver, where we are always leaving the functions to wait for an
1386  * interrupt or a timer event.
1387  *
1388  * From the bottom part of the driver, we should allocate safe memory using
1389  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1390  * to the request list without waiting for it to be serviced! In that case, we
1391  * usually use idetape_queue_pc_head().
1392  */
1393 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1394 {
1395         struct ide_tape_obj *tape = drive->driver_data;
1396         struct request *rq;
1397         int error;
1398
1399         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1400         rq->cmd_type = REQ_TYPE_SPECIAL;
1401         rq->cmd[0] = REQ_IDETAPE_PC1;
1402         rq->buffer = (char *)pc;
1403         error = blk_execute_rq(drive->queue, tape->disk, rq, 0);
1404         blk_put_request(rq);
1405         return error;
1406 }
1407
1408 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1409                 struct ide_atapi_pc *pc, int cmd)
1410 {
1411         idetape_init_pc(pc);
1412         pc->c[0] = START_STOP;
1413         pc->c[4] = cmd;
1414         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1415 }
1416
1417 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1418 {
1419         idetape_tape_t *tape = drive->driver_data;
1420         struct ide_atapi_pc pc;
1421         int load_attempted = 0;
1422
1423         /* Wait for the tape to become ready */
1424         set_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
1425         timeout += jiffies;
1426         while (time_before(jiffies, timeout)) {
1427                 idetape_create_test_unit_ready_cmd(&pc);
1428                 if (!idetape_queue_pc_tail(drive, &pc))
1429                         return 0;
1430                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1431                     || (tape->asc == 0x3A)) {
1432                         /* no media */
1433                         if (load_attempted)
1434                                 return -ENOMEDIUM;
1435                         idetape_create_load_unload_cmd(drive, &pc,
1436                                                         IDETAPE_LU_LOAD_MASK);
1437                         idetape_queue_pc_tail(drive, &pc);
1438                         load_attempted = 1;
1439                 /* not about to be ready */
1440                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1441                              (tape->ascq == 1 || tape->ascq == 8)))
1442                         return -EIO;
1443                 msleep(100);
1444         }
1445         return -EIO;
1446 }
1447
1448 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1449 {
1450         struct ide_atapi_pc pc;
1451         int rc;
1452
1453         idetape_create_write_filemark_cmd(drive, &pc, 0);
1454         rc = idetape_queue_pc_tail(drive, &pc);
1455         if (rc)
1456                 return rc;
1457         idetape_wait_ready(drive, 60 * 5 * HZ);
1458         return 0;
1459 }
1460
1461 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1462 {
1463         idetape_init_pc(pc);
1464         pc->c[0] = READ_POSITION;
1465         pc->req_xfer = 20;
1466 }
1467
1468 static int idetape_read_position(ide_drive_t *drive)
1469 {
1470         idetape_tape_t *tape = drive->driver_data;
1471         struct ide_atapi_pc pc;
1472         int position;
1473
1474         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1475
1476         idetape_create_read_position_cmd(&pc);
1477         if (idetape_queue_pc_tail(drive, &pc))
1478                 return -1;
1479         position = tape->first_frame;
1480         return position;
1481 }
1482
1483 static void idetape_create_locate_cmd(ide_drive_t *drive,
1484                 struct ide_atapi_pc *pc,
1485                 unsigned int block, u8 partition, int skip)
1486 {
1487         idetape_init_pc(pc);
1488         pc->c[0] = POSITION_TO_ELEMENT;
1489         pc->c[1] = 2;
1490         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1491         pc->c[8] = partition;
1492         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1493 }
1494
1495 static int idetape_create_prevent_cmd(ide_drive_t *drive,
1496                 struct ide_atapi_pc *pc, int prevent)
1497 {
1498         idetape_tape_t *tape = drive->driver_data;
1499
1500         /* device supports locking according to capabilities page */
1501         if (!(tape->caps[6] & 0x01))
1502                 return 0;
1503
1504         idetape_init_pc(pc);
1505         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
1506         pc->c[4] = prevent;
1507         return 1;
1508 }
1509
1510 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1511 {
1512         idetape_tape_t *tape = drive->driver_data;
1513
1514         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1515                 return;
1516
1517         clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
1518         tape->merge_bh_size = 0;
1519         if (tape->merge_bh != NULL) {
1520                 ide_tape_kfree_buffer(tape);
1521                 tape->merge_bh = NULL;
1522         }
1523
1524         tape->chrdev_dir = IDETAPE_DIR_NONE;
1525 }
1526
1527 /*
1528  * Position the tape to the requested block using the LOCATE packet command.
1529  * A READ POSITION command is then issued to check where we are positioned. Like
1530  * all higher level operations, we queue the commands at the tail of the request
1531  * queue and wait for their completion.
1532  */
1533 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1534                 u8 partition, int skip)
1535 {
1536         idetape_tape_t *tape = drive->driver_data;
1537         int retval;
1538         struct ide_atapi_pc pc;
1539
1540         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1541                 __ide_tape_discard_merge_buffer(drive);
1542         idetape_wait_ready(drive, 60 * 5 * HZ);
1543         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1544         retval = idetape_queue_pc_tail(drive, &pc);
1545         if (retval)
1546                 return (retval);
1547
1548         idetape_create_read_position_cmd(&pc);
1549         return (idetape_queue_pc_tail(drive, &pc));
1550 }
1551
1552 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1553                                           int restore_position)
1554 {
1555         idetape_tape_t *tape = drive->driver_data;
1556         int seek, position;
1557
1558         __ide_tape_discard_merge_buffer(drive);
1559         if (restore_position) {
1560                 position = idetape_read_position(drive);
1561                 seek = position > 0 ? position : 0;
1562                 if (idetape_position_tape(drive, seek, 0, 0)) {
1563                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1564                                          " %s\n", tape->name, __func__);
1565                         return;
1566                 }
1567         }
1568 }
1569
1570 /*
1571  * Generate a read/write request for the block device interface and wait for it
1572  * to be serviced.
1573  */
1574 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1575                                  struct idetape_bh *bh)
1576 {
1577         idetape_tape_t *tape = drive->driver_data;
1578         struct request *rq;
1579         int ret, errors;
1580
1581         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1582
1583         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1584         rq->cmd_type = REQ_TYPE_SPECIAL;
1585         rq->cmd[0] = cmd;
1586         rq->rq_disk = tape->disk;
1587         rq->special = (void *)bh;
1588         rq->sector = tape->first_frame;
1589         rq->nr_sectors = blocks;
1590         rq->current_nr_sectors = blocks;
1591         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1592
1593         errors = rq->errors;
1594         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1595         blk_put_request(rq);
1596
1597         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1598                 return 0;
1599
1600         if (tape->merge_bh)
1601                 idetape_init_merge_buffer(tape);
1602         if (errors == IDETAPE_ERROR_GENERAL)
1603                 return -EIO;
1604         return ret;
1605 }
1606
1607 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1608 {
1609         idetape_init_pc(pc);
1610         pc->c[0] = INQUIRY;
1611         pc->c[4] = 254;
1612         pc->req_xfer = 254;
1613 }
1614
1615 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1616                 struct ide_atapi_pc *pc)
1617 {
1618         idetape_init_pc(pc);
1619         pc->c[0] = REZERO_UNIT;
1620         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1621 }
1622
1623 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1624 {
1625         idetape_init_pc(pc);
1626         pc->c[0] = ERASE;
1627         pc->c[1] = 1;
1628         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1629 }
1630
1631 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1632 {
1633         idetape_init_pc(pc);
1634         pc->c[0] = SPACE;
1635         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1636         pc->c[1] = cmd;
1637         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1638 }
1639
1640 /* Queue up a character device originated write request. */
1641 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1642 {
1643         idetape_tape_t *tape = drive->driver_data;
1644
1645         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1646
1647         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1648                                      blocks, tape->merge_bh);
1649 }
1650
1651 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1652 {
1653         idetape_tape_t *tape = drive->driver_data;
1654         int blocks, min;
1655         struct idetape_bh *bh;
1656
1657         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1658                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1659                                 " but we are not writing.\n");
1660                 return;
1661         }
1662         if (tape->merge_bh_size > tape->buffer_size) {
1663                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1664                 tape->merge_bh_size = tape->buffer_size;
1665         }
1666         if (tape->merge_bh_size) {
1667                 blocks = tape->merge_bh_size / tape->blk_size;
1668                 if (tape->merge_bh_size % tape->blk_size) {
1669                         unsigned int i;
1670
1671                         blocks++;
1672                         i = tape->blk_size - tape->merge_bh_size %
1673                                 tape->blk_size;
1674                         bh = tape->bh->b_reqnext;
1675                         while (bh) {
1676                                 atomic_set(&bh->b_count, 0);
1677                                 bh = bh->b_reqnext;
1678                         }
1679                         bh = tape->bh;
1680                         while (i) {
1681                                 if (bh == NULL) {
1682                                         printk(KERN_INFO "ide-tape: bug,"
1683                                                          " bh NULL\n");
1684                                         break;
1685                                 }
1686                                 min = min(i, (unsigned int)(bh->b_size -
1687                                                 atomic_read(&bh->b_count)));
1688                                 memset(bh->b_data + atomic_read(&bh->b_count),
1689                                                 0, min);
1690                                 atomic_add(min, &bh->b_count);
1691                                 i -= min;
1692                                 bh = bh->b_reqnext;
1693                         }
1694                 }
1695                 (void) idetape_add_chrdev_write_request(drive, blocks);
1696                 tape->merge_bh_size = 0;
1697         }
1698         if (tape->merge_bh != NULL) {
1699                 ide_tape_kfree_buffer(tape);
1700                 tape->merge_bh = NULL;
1701         }
1702         tape->chrdev_dir = IDETAPE_DIR_NONE;
1703 }
1704
1705 static int idetape_init_read(ide_drive_t *drive)
1706 {
1707         idetape_tape_t *tape = drive->driver_data;
1708         int bytes_read;
1709
1710         /* Initialize read operation */
1711         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1712                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1713                         ide_tape_flush_merge_buffer(drive);
1714                         idetape_flush_tape_buffers(drive);
1715                 }
1716                 if (tape->merge_bh || tape->merge_bh_size) {
1717                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1718                                          " 0 now\n");
1719                         tape->merge_bh_size = 0;
1720                 }
1721                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1722                 if (!tape->merge_bh)
1723                         return -ENOMEM;
1724                 tape->chrdev_dir = IDETAPE_DIR_READ;
1725
1726                 /*
1727                  * Issue a read 0 command to ensure that DSC handshake is
1728                  * switched from completion mode to buffer available mode.
1729                  * No point in issuing this if DSC overlap isn't supported, some
1730                  * drives (Seagate STT3401A) will return an error.
1731                  */
1732                 if (drive->dsc_overlap) {
1733                         bytes_read = idetape_queue_rw_tail(drive,
1734                                                         REQ_IDETAPE_READ, 0,
1735                                                         tape->merge_bh);
1736                         if (bytes_read < 0) {
1737                                 ide_tape_kfree_buffer(tape);
1738                                 tape->merge_bh = NULL;
1739                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1740                                 return bytes_read;
1741                         }
1742                 }
1743         }
1744
1745         return 0;
1746 }
1747
1748 /* called from idetape_chrdev_read() to service a chrdev read request. */
1749 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1750 {
1751         idetape_tape_t *tape = drive->driver_data;
1752
1753         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1754
1755         /* If we are at a filemark, return a read length of 0 */
1756         if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1757                 return 0;
1758
1759         idetape_init_read(drive);
1760
1761         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1762                                      tape->merge_bh);
1763 }
1764
1765 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1766 {
1767         idetape_tape_t *tape = drive->driver_data;
1768         struct idetape_bh *bh;
1769         int blocks;
1770
1771         while (bcount) {
1772                 unsigned int count;
1773
1774                 bh = tape->merge_bh;
1775                 count = min(tape->buffer_size, bcount);
1776                 bcount -= count;
1777                 blocks = count / tape->blk_size;
1778                 while (count) {
1779                         atomic_set(&bh->b_count,
1780                                    min(count, (unsigned int)bh->b_size));
1781                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1782                         count -= atomic_read(&bh->b_count);
1783                         bh = bh->b_reqnext;
1784                 }
1785                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1786                                       tape->merge_bh);
1787         }
1788 }
1789
1790 /*
1791  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1792  * currently support only one partition.
1793  */
1794 static int idetape_rewind_tape(ide_drive_t *drive)
1795 {
1796         int retval;
1797         struct ide_atapi_pc pc;
1798         idetape_tape_t *tape;
1799         tape = drive->driver_data;
1800
1801         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1802
1803         idetape_create_rewind_cmd(drive, &pc);
1804         retval = idetape_queue_pc_tail(drive, &pc);
1805         if (retval)
1806                 return retval;
1807
1808         idetape_create_read_position_cmd(&pc);
1809         retval = idetape_queue_pc_tail(drive, &pc);
1810         if (retval)
1811                 return retval;
1812         return 0;
1813 }
1814
1815 /* mtio.h compatible commands should be issued to the chrdev interface. */
1816 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1817                                 unsigned long arg)
1818 {
1819         idetape_tape_t *tape = drive->driver_data;
1820         void __user *argp = (void __user *)arg;
1821
1822         struct idetape_config {
1823                 int dsc_rw_frequency;
1824                 int dsc_media_access_frequency;
1825                 int nr_stages;
1826         } config;
1827
1828         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1829
1830         switch (cmd) {
1831         case 0x0340:
1832                 if (copy_from_user(&config, argp, sizeof(config)))
1833                         return -EFAULT;
1834                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1835                 break;
1836         case 0x0350:
1837                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1838                 config.nr_stages = 1;
1839                 if (copy_to_user(argp, &config, sizeof(config)))
1840                         return -EFAULT;
1841                 break;
1842         default:
1843                 return -EIO;
1844         }
1845         return 0;
1846 }
1847
1848 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1849                                         int mt_count)
1850 {
1851         idetape_tape_t *tape = drive->driver_data;
1852         struct ide_atapi_pc pc;
1853         int retval, count = 0;
1854         int sprev = !!(tape->caps[4] & 0x20);
1855
1856         if (mt_count == 0)
1857                 return 0;
1858         if (MTBSF == mt_op || MTBSFM == mt_op) {
1859                 if (!sprev)
1860                         return -EIO;
1861                 mt_count = -mt_count;
1862         }
1863
1864         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1865                 tape->merge_bh_size = 0;
1866                 if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1867                         ++count;
1868                 ide_tape_discard_merge_buffer(drive, 0);
1869         }
1870
1871         switch (mt_op) {
1872         case MTFSF:
1873         case MTBSF:
1874                 idetape_create_space_cmd(&pc, mt_count - count,
1875                                          IDETAPE_SPACE_OVER_FILEMARK);
1876                 return idetape_queue_pc_tail(drive, &pc);
1877         case MTFSFM:
1878         case MTBSFM:
1879                 if (!sprev)
1880                         return -EIO;
1881                 retval = idetape_space_over_filemarks(drive, MTFSF,
1882                                                       mt_count - count);
1883                 if (retval)
1884                         return retval;
1885                 count = (MTBSFM == mt_op ? 1 : -1);
1886                 return idetape_space_over_filemarks(drive, MTFSF, count);
1887         default:
1888                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1889                                 mt_op);
1890                 return -EIO;
1891         }
1892 }
1893
1894 /*
1895  * Our character device read / write functions.
1896  *
1897  * The tape is optimized to maximize throughput when it is transferring an
1898  * integral number of the "continuous transfer limit", which is a parameter of
1899  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1900  *
1901  * As of version 1.3 of the driver, the character device provides an abstract
1902  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1903  * same backup/restore procedure is supported. The driver will internally
1904  * convert the requests to the recommended transfer unit, so that an unmatch
1905  * between the user's block size to the recommended size will only result in a
1906  * (slightly) increased driver overhead, but will no longer hit performance.
1907  * This is not applicable to Onstream.
1908  */
1909 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1910                                    size_t count, loff_t *ppos)
1911 {
1912         struct ide_tape_obj *tape = ide_tape_f(file);
1913         ide_drive_t *drive = tape->drive;
1914         ssize_t bytes_read, temp, actually_read = 0, rc;
1915         ssize_t ret = 0;
1916         u16 ctl = *(u16 *)&tape->caps[12];
1917
1918         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1919
1920         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1921                 if (test_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags))
1922                         if (count > tape->blk_size &&
1923                             (count % tape->blk_size) == 0)
1924                                 tape->user_bs_factor = count / tape->blk_size;
1925         }
1926         rc = idetape_init_read(drive);
1927         if (rc < 0)
1928                 return rc;
1929         if (count == 0)
1930                 return (0);
1931         if (tape->merge_bh_size) {
1932                 actually_read = min((unsigned int)(tape->merge_bh_size),
1933                                     (unsigned int)count);
1934                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1935                         ret = -EFAULT;
1936                 buf += actually_read;
1937                 tape->merge_bh_size -= actually_read;
1938                 count -= actually_read;
1939         }
1940         while (count >= tape->buffer_size) {
1941                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1942                 if (bytes_read <= 0)
1943                         goto finish;
1944                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1945                         ret = -EFAULT;
1946                 buf += bytes_read;
1947                 count -= bytes_read;
1948                 actually_read += bytes_read;
1949         }
1950         if (count) {
1951                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1952                 if (bytes_read <= 0)
1953                         goto finish;
1954                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1955                 if (idetape_copy_stage_to_user(tape, buf, temp))
1956                         ret = -EFAULT;
1957                 actually_read += temp;
1958                 tape->merge_bh_size = bytes_read-temp;
1959         }
1960 finish:
1961         if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
1962                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1963
1964                 idetape_space_over_filemarks(drive, MTFSF, 1);
1965                 return 0;
1966         }
1967
1968         return ret ? ret : actually_read;
1969 }
1970
1971 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1972                                      size_t count, loff_t *ppos)
1973 {
1974         struct ide_tape_obj *tape = ide_tape_f(file);
1975         ide_drive_t *drive = tape->drive;
1976         ssize_t actually_written = 0;
1977         ssize_t ret = 0;
1978         u16 ctl = *(u16 *)&tape->caps[12];
1979
1980         /* The drive is write protected. */
1981         if (tape->write_prot)
1982                 return -EACCES;
1983
1984         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1985
1986         /* Initialize write operation */
1987         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1988                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1989                         ide_tape_discard_merge_buffer(drive, 1);
1990                 if (tape->merge_bh || tape->merge_bh_size) {
1991                         printk(KERN_ERR "ide-tape: merge_bh_size "
1992                                 "should be 0 now\n");
1993                         tape->merge_bh_size = 0;
1994                 }
1995                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1996                 if (!tape->merge_bh)
1997                         return -ENOMEM;
1998                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1999                 idetape_init_merge_buffer(tape);
2000
2001                 /*
2002                  * Issue a write 0 command to ensure that DSC handshake is
2003                  * switched from completion mode to buffer available mode. No
2004                  * point in issuing this if DSC overlap isn't supported, some
2005                  * drives (Seagate STT3401A) will return an error.
2006                  */
2007                 if (drive->dsc_overlap) {
2008                         ssize_t retval = idetape_queue_rw_tail(drive,
2009                                                         REQ_IDETAPE_WRITE, 0,
2010                                                         tape->merge_bh);
2011                         if (retval < 0) {
2012                                 ide_tape_kfree_buffer(tape);
2013                                 tape->merge_bh = NULL;
2014                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2015                                 return retval;
2016                         }
2017                 }
2018         }
2019         if (count == 0)
2020                 return (0);
2021         if (tape->merge_bh_size) {
2022                 if (tape->merge_bh_size >= tape->buffer_size) {
2023                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
2024                         tape->merge_bh_size = 0;
2025                 }
2026                 actually_written = min((unsigned int)
2027                                 (tape->buffer_size - tape->merge_bh_size),
2028                                 (unsigned int)count);
2029                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
2030                                 ret = -EFAULT;
2031                 buf += actually_written;
2032                 tape->merge_bh_size += actually_written;
2033                 count -= actually_written;
2034
2035                 if (tape->merge_bh_size == tape->buffer_size) {
2036                         ssize_t retval;
2037                         tape->merge_bh_size = 0;
2038                         retval = idetape_add_chrdev_write_request(drive, ctl);
2039                         if (retval <= 0)
2040                                 return (retval);
2041                 }
2042         }
2043         while (count >= tape->buffer_size) {
2044                 ssize_t retval;
2045                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
2046                         ret = -EFAULT;
2047                 buf += tape->buffer_size;
2048                 count -= tape->buffer_size;
2049                 retval = idetape_add_chrdev_write_request(drive, ctl);
2050                 actually_written += tape->buffer_size;
2051                 if (retval <= 0)
2052                         return (retval);
2053         }
2054         if (count) {
2055                 actually_written += count;
2056                 if (idetape_copy_stage_from_user(tape, buf, count))
2057                         ret = -EFAULT;
2058                 tape->merge_bh_size += count;
2059         }
2060         return ret ? ret : actually_written;
2061 }
2062
2063 static int idetape_write_filemark(ide_drive_t *drive)
2064 {
2065         struct ide_atapi_pc pc;
2066
2067         /* Write a filemark */
2068         idetape_create_write_filemark_cmd(drive, &pc, 1);
2069         if (idetape_queue_pc_tail(drive, &pc)) {
2070                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
2071                 return -EIO;
2072         }
2073         return 0;
2074 }
2075
2076 /*
2077  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
2078  * requested.
2079  *
2080  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
2081  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
2082  * usually not supported.
2083  *
2084  * The following commands are currently not supported:
2085  *
2086  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
2087  * MT_ST_WRITE_THRESHOLD.
2088  */
2089 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
2090 {
2091         idetape_tape_t *tape = drive->driver_data;
2092         struct ide_atapi_pc pc;
2093         int i, retval;
2094
2095         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
2096                         mt_op, mt_count);
2097
2098         switch (mt_op) {
2099         case MTFSF:
2100         case MTFSFM:
2101         case MTBSF:
2102         case MTBSFM:
2103                 if (!mt_count)
2104                         return 0;
2105                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
2106         default:
2107                 break;
2108         }
2109
2110         switch (mt_op) {
2111         case MTWEOF:
2112                 if (tape->write_prot)
2113                         return -EACCES;
2114                 ide_tape_discard_merge_buffer(drive, 1);
2115                 for (i = 0; i < mt_count; i++) {
2116                         retval = idetape_write_filemark(drive);
2117                         if (retval)
2118                                 return retval;
2119                 }
2120                 return 0;
2121         case MTREW:
2122                 ide_tape_discard_merge_buffer(drive, 0);
2123                 if (idetape_rewind_tape(drive))
2124                         return -EIO;
2125                 return 0;
2126         case MTLOAD:
2127                 ide_tape_discard_merge_buffer(drive, 0);
2128                 idetape_create_load_unload_cmd(drive, &pc,
2129                                                IDETAPE_LU_LOAD_MASK);
2130                 return idetape_queue_pc_tail(drive, &pc);
2131         case MTUNLOAD:
2132         case MTOFFL:
2133                 /*
2134                  * If door is locked, attempt to unlock before
2135                  * attempting to eject.
2136                  */
2137                 if (tape->door_locked) {
2138                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2139                                 if (!idetape_queue_pc_tail(drive, &pc))
2140                                         tape->door_locked = DOOR_UNLOCKED;
2141                 }
2142                 ide_tape_discard_merge_buffer(drive, 0);
2143                 idetape_create_load_unload_cmd(drive, &pc,
2144                                               !IDETAPE_LU_LOAD_MASK);
2145                 retval = idetape_queue_pc_tail(drive, &pc);
2146                 if (!retval)
2147                         clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
2148                 return retval;
2149         case MTNOP:
2150                 ide_tape_discard_merge_buffer(drive, 0);
2151                 return idetape_flush_tape_buffers(drive);
2152         case MTRETEN:
2153                 ide_tape_discard_merge_buffer(drive, 0);
2154                 idetape_create_load_unload_cmd(drive, &pc,
2155                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2156                 return idetape_queue_pc_tail(drive, &pc);
2157         case MTEOM:
2158                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
2159                 return idetape_queue_pc_tail(drive, &pc);
2160         case MTERASE:
2161                 (void)idetape_rewind_tape(drive);
2162                 idetape_create_erase_cmd(&pc);
2163                 return idetape_queue_pc_tail(drive, &pc);
2164         case MTSETBLK:
2165                 if (mt_count) {
2166                         if (mt_count < tape->blk_size ||
2167                             mt_count % tape->blk_size)
2168                                 return -EIO;
2169                         tape->user_bs_factor = mt_count / tape->blk_size;
2170                         clear_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2171                 } else
2172                         set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2173                 return 0;
2174         case MTSEEK:
2175                 ide_tape_discard_merge_buffer(drive, 0);
2176                 return idetape_position_tape(drive,
2177                         mt_count * tape->user_bs_factor, tape->partition, 0);
2178         case MTSETPART:
2179                 ide_tape_discard_merge_buffer(drive, 0);
2180                 return idetape_position_tape(drive, 0, mt_count, 0);
2181         case MTFSR:
2182         case MTBSR:
2183         case MTLOCK:
2184                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
2185                         return 0;
2186                 retval = idetape_queue_pc_tail(drive, &pc);
2187                 if (retval)
2188                         return retval;
2189                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
2190                 return 0;
2191         case MTUNLOCK:
2192                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
2193                         return 0;
2194                 retval = idetape_queue_pc_tail(drive, &pc);
2195                 if (retval)
2196                         return retval;
2197                 tape->door_locked = DOOR_UNLOCKED;
2198                 return 0;
2199         default:
2200                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2201                                 mt_op);
2202                 return -EIO;
2203         }
2204 }
2205
2206 /*
2207  * Our character device ioctls. General mtio.h magnetic io commands are
2208  * supported here, and not in the corresponding block interface. Our own
2209  * ide-tape ioctls are supported on both interfaces.
2210  */
2211 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
2212                                 unsigned int cmd, unsigned long arg)
2213 {
2214         struct ide_tape_obj *tape = ide_tape_f(file);
2215         ide_drive_t *drive = tape->drive;
2216         struct mtop mtop;
2217         struct mtget mtget;
2218         struct mtpos mtpos;
2219         int block_offset = 0, position = tape->first_frame;
2220         void __user *argp = (void __user *)arg;
2221
2222         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
2223
2224         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2225                 ide_tape_flush_merge_buffer(drive);
2226                 idetape_flush_tape_buffers(drive);
2227         }
2228         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
2229                 block_offset = tape->merge_bh_size /
2230                         (tape->blk_size * tape->user_bs_factor);
2231                 position = idetape_read_position(drive);
2232                 if (position < 0)
2233                         return -EIO;
2234         }
2235         switch (cmd) {
2236         case MTIOCTOP:
2237                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
2238                         return -EFAULT;
2239                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
2240         case MTIOCGET:
2241                 memset(&mtget, 0, sizeof(struct mtget));
2242                 mtget.mt_type = MT_ISSCSI2;
2243                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
2244                 mtget.mt_dsreg =
2245                         ((tape->blk_size * tape->user_bs_factor)
2246                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
2247
2248                 if (tape->drv_write_prot)
2249                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
2250
2251                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
2252                         return -EFAULT;
2253                 return 0;
2254         case MTIOCPOS:
2255                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
2256                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
2257                         return -EFAULT;
2258                 return 0;
2259         default:
2260                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2261                         ide_tape_discard_merge_buffer(drive, 1);
2262                 return idetape_blkdev_ioctl(drive, cmd, arg);
2263         }
2264 }
2265
2266 /*
2267  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
2268  * block size with the reported value.
2269  */
2270 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
2271 {
2272         idetape_tape_t *tape = drive->driver_data;
2273         struct ide_atapi_pc pc;
2274
2275         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
2276         if (idetape_queue_pc_tail(drive, &pc)) {
2277                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
2278                 if (tape->blk_size == 0) {
2279                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
2280                                             "block size, assuming 32k\n");
2281                         tape->blk_size = 32768;
2282                 }
2283                 return;
2284         }
2285         tape->blk_size = (pc.buf[4 + 5] << 16) +
2286                                 (pc.buf[4 + 6] << 8)  +
2287                                  pc.buf[4 + 7];
2288         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
2289 }
2290
2291 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
2292 {
2293         unsigned int minor = iminor(inode), i = minor & ~0xc0;
2294         ide_drive_t *drive;
2295         idetape_tape_t *tape;
2296         struct ide_atapi_pc pc;
2297         int retval;
2298
2299         if (i >= MAX_HWIFS * MAX_DRIVES)
2300                 return -ENXIO;
2301
2302         tape = ide_tape_chrdev_get(i);
2303         if (!tape)
2304                 return -ENXIO;
2305
2306         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2307
2308         /*
2309          * We really want to do nonseekable_open(inode, filp); here, but some
2310          * versions of tar incorrectly call lseek on tapes and bail out if that
2311          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
2312          */
2313         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
2314
2315         drive = tape->drive;
2316
2317         filp->private_data = tape;
2318
2319         if (test_and_set_bit(IDETAPE_FLAG_BUSY, &tape->flags)) {
2320                 retval = -EBUSY;
2321                 goto out_put_tape;
2322         }
2323
2324         retval = idetape_wait_ready(drive, 60 * HZ);
2325         if (retval) {
2326                 clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2327                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
2328                 goto out_put_tape;
2329         }
2330
2331         idetape_read_position(drive);
2332         if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
2333                 (void)idetape_rewind_tape(drive);
2334
2335         /* Read block size and write protect status from drive. */
2336         ide_tape_get_bsize_from_bdesc(drive);
2337
2338         /* Set write protect flag if device is opened as read-only. */
2339         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
2340                 tape->write_prot = 1;
2341         else
2342                 tape->write_prot = tape->drv_write_prot;
2343
2344         /* Make sure drive isn't write protected if user wants to write. */
2345         if (tape->write_prot) {
2346                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
2347                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
2348                         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2349                         retval = -EROFS;
2350                         goto out_put_tape;
2351                 }
2352         }
2353
2354         /* Lock the tape drive door so user can't eject. */
2355         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2356                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
2357                         if (!idetape_queue_pc_tail(drive, &pc)) {
2358                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2359                                         tape->door_locked = DOOR_LOCKED;
2360                         }
2361                 }
2362         }
2363         return 0;
2364
2365 out_put_tape:
2366         ide_tape_put(tape);
2367         return retval;
2368 }
2369
2370 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2371 {
2372         idetape_tape_t *tape = drive->driver_data;
2373
2374         ide_tape_flush_merge_buffer(drive);
2375         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2376         if (tape->merge_bh != NULL) {
2377                 idetape_pad_zeros(drive, tape->blk_size *
2378                                 (tape->user_bs_factor - 1));
2379                 ide_tape_kfree_buffer(tape);
2380                 tape->merge_bh = NULL;
2381         }
2382         idetape_write_filemark(drive);
2383         idetape_flush_tape_buffers(drive);
2384         idetape_flush_tape_buffers(drive);
2385 }
2386
2387 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2388 {
2389         struct ide_tape_obj *tape = ide_tape_f(filp);
2390         ide_drive_t *drive = tape->drive;
2391         struct ide_atapi_pc pc;
2392         unsigned int minor = iminor(inode);
2393
2394         lock_kernel();
2395         tape = drive->driver_data;
2396
2397         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2398
2399         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2400                 idetape_write_release(drive, minor);
2401         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2402                 if (minor < 128)
2403                         ide_tape_discard_merge_buffer(drive, 1);
2404         }
2405
2406         if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
2407                 (void) idetape_rewind_tape(drive);
2408         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2409                 if (tape->door_locked == DOOR_LOCKED) {
2410                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
2411                                 if (!idetape_queue_pc_tail(drive, &pc))
2412                                         tape->door_locked = DOOR_UNLOCKED;
2413                         }
2414                 }
2415         }
2416         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2417         ide_tape_put(tape);
2418         unlock_kernel();
2419         return 0;
2420 }
2421
2422 /*
2423  * check the contents of the ATAPI IDENTIFY command results. We return:
2424  *
2425  * 1 - If the tape can be supported by us, based on the information we have so
2426  * far.
2427  *
2428  * 0 - If this tape driver is not currently supported by us.
2429  */
2430 static int idetape_identify_device(ide_drive_t *drive)
2431 {
2432         u8 gcw[2], protocol, device_type, removable, packet_size;
2433
2434         if (drive->id_read == 0)
2435                 return 1;
2436
2437         *((unsigned short *) &gcw) = drive->id->config;
2438
2439         protocol        =   (gcw[1] & 0xC0) >> 6;
2440         device_type     =    gcw[1] & 0x1F;
2441         removable       = !!(gcw[0] & 0x80);
2442         packet_size     =    gcw[0] & 0x3;
2443
2444         /* Check that we can support this device */
2445         if (protocol != 2)
2446                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
2447                                 protocol);
2448         else if (device_type != 1)
2449                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
2450                                 "to tape\n", device_type);
2451         else if (!removable)
2452                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
2453         else if (packet_size != 0) {
2454                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
2455                                 " bytes\n", packet_size);
2456         } else
2457                 return 1;
2458         return 0;
2459 }
2460
2461 static void idetape_get_inquiry_results(ide_drive_t *drive)
2462 {
2463         idetape_tape_t *tape = drive->driver_data;
2464         struct ide_atapi_pc pc;
2465         char fw_rev[6], vendor_id[10], product_id[18];
2466
2467         idetape_create_inquiry_cmd(&pc);
2468         if (idetape_queue_pc_tail(drive, &pc)) {
2469                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2470                                 tape->name);
2471                 return;
2472         }
2473         memcpy(vendor_id, &pc.buf[8], 8);
2474         memcpy(product_id, &pc.buf[16], 16);
2475         memcpy(fw_rev, &pc.buf[32], 4);
2476
2477         ide_fixstring(vendor_id, 10, 0);
2478         ide_fixstring(product_id, 18, 0);
2479         ide_fixstring(fw_rev, 6, 0);
2480
2481         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
2482                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2483 }
2484
2485 /*
2486  * Ask the tape about its various parameters. In particular, we will adjust our
2487  * data transfer buffer size to the recommended value as returned by the tape.
2488  */
2489 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2490 {
2491         idetape_tape_t *tape = drive->driver_data;
2492         struct ide_atapi_pc pc;
2493         u8 *caps;
2494         u8 speed, max_speed;
2495
2496         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2497         if (idetape_queue_pc_tail(drive, &pc)) {
2498                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2499                                 " some default values\n");
2500                 tape->blk_size = 512;
2501                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2502                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2503                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2504                 return;
2505         }
2506         caps = pc.buf + 4 + pc.buf[3];
2507
2508         /* convert to host order and save for later use */
2509         speed = be16_to_cpu(*(u16 *)&caps[14]);
2510         max_speed = be16_to_cpu(*(u16 *)&caps[8]);
2511
2512         put_unaligned(max_speed, (u16 *)&caps[8]);
2513         put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
2514         put_unaligned(speed, (u16 *)&caps[14]);
2515         put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
2516
2517         if (!speed) {
2518                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2519                                 "(assuming 650KB/sec)\n", drive->name);
2520                 put_unaligned(650, (u16 *)&caps[14]);
2521         }
2522         if (!max_speed) {
2523                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2524                                 "(assuming 650KB/sec)\n", drive->name);
2525                 put_unaligned(650, (u16 *)&caps[8]);
2526         }
2527
2528         memcpy(&tape->caps, caps, 20);
2529         if (caps[7] & 0x02)
2530                 tape->blk_size = 512;
2531         else if (caps[7] & 0x04)
2532                 tape->blk_size = 1024;
2533 }
2534
2535 #ifdef CONFIG_IDE_PROC_FS
2536 static void idetape_add_settings(ide_drive_t *drive)
2537 {
2538         idetape_tape_t *tape = drive->driver_data;
2539
2540         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2541                         1, 2, (u16 *)&tape->caps[16], NULL);
2542         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2543                         1, 1, (u16 *)&tape->caps[14], NULL);
2544         ide_add_setting(drive, "buffer_size", SETTING_READ, TYPE_INT, 0, 0xffff,
2545                         1, 1024, &tape->buffer_size, NULL);
2546         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
2547                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
2548                         NULL);
2549         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
2550                         1, &drive->dsc_overlap, NULL);
2551         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
2552                         1, 1, &tape->avg_speed, NULL);
2553         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
2554                         1, &tape->debug_mask, NULL);
2555 }
2556 #else
2557 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
2558 #endif
2559
2560 /*
2561  * The function below is called to:
2562  *
2563  * 1. Initialize our various state variables.
2564  * 2. Ask the tape for its capabilities.
2565  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2566  * is chosen based on the recommendation which we received in step 2.
2567  *
2568  * Note that at this point ide.c already assigned us an irq, so that we can
2569  * queue requests here and wait for their completion.
2570  */
2571 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2572 {
2573         unsigned long t;
2574         int speed;
2575         int buffer_size;
2576         u8 gcw[2];
2577         u16 *ctl = (u16 *)&tape->caps[12];
2578
2579         spin_lock_init(&tape->lock);
2580         drive->dsc_overlap = 1;
2581         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2582                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2583                                  tape->name);
2584                 drive->dsc_overlap = 0;
2585         }
2586         /* Seagate Travan drives do not support DSC overlap. */
2587         if (strstr(drive->id->model, "Seagate STT3401"))
2588                 drive->dsc_overlap = 0;
2589         tape->minor = minor;
2590         tape->name[0] = 'h';
2591         tape->name[1] = 't';
2592         tape->name[2] = '0' + minor;
2593         tape->chrdev_dir = IDETAPE_DIR_NONE;
2594         tape->pc = tape->pc_stack;
2595         *((unsigned short *) &gcw) = drive->id->config;
2596
2597         /* Command packet DRQ type */
2598         if (((gcw[0] & 0x60) >> 5) == 1)
2599                 set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
2600
2601         idetape_get_inquiry_results(drive);
2602         idetape_get_mode_sense_results(drive);
2603         ide_tape_get_bsize_from_bdesc(drive);
2604         tape->user_bs_factor = 1;
2605         tape->buffer_size = *ctl * tape->blk_size;
2606         while (tape->buffer_size > 0xffff) {
2607                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2608                 *ctl /= 2;
2609                 tape->buffer_size = *ctl * tape->blk_size;
2610         }
2611         buffer_size = tape->buffer_size;
2612         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2613         if (buffer_size % PAGE_SIZE) {
2614                 tape->pages_per_buffer++;
2615                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2616         }
2617
2618         /* select the "best" DSC read/write polling freq */
2619         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2620
2621         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2622
2623         /*
2624          * Ensure that the number we got makes sense; limit it within
2625          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2626          */
2627         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2628                                          IDETAPE_DSC_RW_MAX);
2629         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2630                 "%lums tDSC%s\n",
2631                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2632                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2633                 tape->buffer_size / 1024,
2634                 tape->best_dsc_rw_freq * 1000 / HZ,
2635                 drive->using_dma ? ", DMA":"");
2636
2637         idetape_add_settings(drive);
2638 }
2639
2640 static void ide_tape_remove(ide_drive_t *drive)
2641 {
2642         idetape_tape_t *tape = drive->driver_data;
2643
2644         ide_proc_unregister_driver(drive, tape->driver);
2645
2646         ide_unregister_region(tape->disk);
2647
2648         ide_tape_put(tape);
2649 }
2650
2651 static void ide_tape_release(struct kref *kref)
2652 {
2653         struct ide_tape_obj *tape = to_ide_tape(kref);
2654         ide_drive_t *drive = tape->drive;
2655         struct gendisk *g = tape->disk;
2656
2657         BUG_ON(tape->merge_bh_size);
2658
2659         drive->dsc_overlap = 0;
2660         drive->driver_data = NULL;
2661         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2662         device_destroy(idetape_sysfs_class,
2663                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2664         idetape_devs[tape->minor] = NULL;
2665         g->private_data = NULL;
2666         put_disk(g);
2667         kfree(tape);
2668 }
2669
2670 #ifdef CONFIG_IDE_PROC_FS
2671 static int proc_idetape_read_name
2672         (char *page, char **start, off_t off, int count, int *eof, void *data)
2673 {
2674         ide_drive_t     *drive = (ide_drive_t *) data;
2675         idetape_tape_t  *tape = drive->driver_data;
2676         char            *out = page;
2677         int             len;
2678
2679         len = sprintf(out, "%s\n", tape->name);
2680         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2681 }
2682
2683 static ide_proc_entry_t idetape_proc[] = {
2684         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2685         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2686         { NULL, 0, NULL, NULL }
2687 };
2688 #endif
2689
2690 static int ide_tape_probe(ide_drive_t *);
2691
2692 static ide_driver_t idetape_driver = {
2693         .gen_driver = {
2694                 .owner          = THIS_MODULE,
2695                 .name           = "ide-tape",
2696                 .bus            = &ide_bus_type,
2697         },
2698         .probe                  = ide_tape_probe,
2699         .remove                 = ide_tape_remove,
2700         .version                = IDETAPE_VERSION,
2701         .media                  = ide_tape,
2702         .supports_dsc_overlap   = 1,
2703         .do_request             = idetape_do_request,
2704         .end_request            = idetape_end_request,
2705         .error                  = __ide_error,
2706         .abort                  = __ide_abort,
2707 #ifdef CONFIG_IDE_PROC_FS
2708         .proc                   = idetape_proc,
2709 #endif
2710 };
2711
2712 /* Our character device supporting functions, passed to register_chrdev. */
2713 static const struct file_operations idetape_fops = {
2714         .owner          = THIS_MODULE,
2715         .read           = idetape_chrdev_read,
2716         .write          = idetape_chrdev_write,
2717         .ioctl          = idetape_chrdev_ioctl,
2718         .open           = idetape_chrdev_open,
2719         .release        = idetape_chrdev_release,
2720 };
2721
2722 static int idetape_open(struct inode *inode, struct file *filp)
2723 {
2724         struct gendisk *disk = inode->i_bdev->bd_disk;
2725         struct ide_tape_obj *tape;
2726
2727         tape = ide_tape_get(disk);
2728         if (!tape)
2729                 return -ENXIO;
2730
2731         return 0;
2732 }
2733
2734 static int idetape_release(struct inode *inode, struct file *filp)
2735 {
2736         struct gendisk *disk = inode->i_bdev->bd_disk;
2737         struct ide_tape_obj *tape = ide_tape_g(disk);
2738
2739         ide_tape_put(tape);
2740
2741         return 0;
2742 }
2743
2744 static int idetape_ioctl(struct inode *inode, struct file *file,
2745                         unsigned int cmd, unsigned long arg)
2746 {
2747         struct block_device *bdev = inode->i_bdev;
2748         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2749         ide_drive_t *drive = tape->drive;
2750         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2751         if (err == -EINVAL)
2752                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2753         return err;
2754 }
2755
2756 static struct block_device_operations idetape_block_ops = {
2757         .owner          = THIS_MODULE,
2758         .open           = idetape_open,
2759         .release        = idetape_release,
2760         .ioctl          = idetape_ioctl,
2761 };
2762
2763 static int ide_tape_probe(ide_drive_t *drive)
2764 {
2765         idetape_tape_t *tape;
2766         struct gendisk *g;
2767         int minor;
2768
2769         if (!strstr("ide-tape", drive->driver_req))
2770                 goto failed;
2771         if (!drive->present)
2772                 goto failed;
2773         if (drive->media != ide_tape)
2774                 goto failed;
2775         if (!idetape_identify_device(drive)) {
2776                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2777                                 " the driver\n", drive->name);
2778                 goto failed;
2779         }
2780         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2781         if (tape == NULL) {
2782                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2783                                 drive->name);
2784                 goto failed;
2785         }
2786
2787         g = alloc_disk(1 << PARTN_BITS);
2788         if (!g)
2789                 goto out_free_tape;
2790
2791         ide_init_disk(g, drive);
2792
2793         ide_proc_register_driver(drive, &idetape_driver);
2794
2795         kref_init(&tape->kref);
2796
2797         tape->drive = drive;
2798         tape->driver = &idetape_driver;
2799         tape->disk = g;
2800
2801         g->private_data = &tape->driver;
2802
2803         drive->driver_data = tape;
2804
2805         mutex_lock(&idetape_ref_mutex);
2806         for (minor = 0; idetape_devs[minor]; minor++)
2807                 ;
2808         idetape_devs[minor] = tape;
2809         mutex_unlock(&idetape_ref_mutex);
2810
2811         idetape_setup(drive, tape, minor);
2812
2813         device_create(idetape_sysfs_class, &drive->gendev,
2814                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
2815         device_create(idetape_sysfs_class, &drive->gendev,
2816                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
2817
2818         g->fops = &idetape_block_ops;
2819         ide_register_region(g);
2820
2821         return 0;
2822
2823 out_free_tape:
2824         kfree(tape);
2825 failed:
2826         return -ENODEV;
2827 }
2828
2829 static void __exit idetape_exit(void)
2830 {
2831         driver_unregister(&idetape_driver.gen_driver);
2832         class_destroy(idetape_sysfs_class);
2833         unregister_chrdev(IDETAPE_MAJOR, "ht");
2834 }
2835
2836 static int __init idetape_init(void)
2837 {
2838         int error = 1;
2839         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2840         if (IS_ERR(idetape_sysfs_class)) {
2841                 idetape_sysfs_class = NULL;
2842                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2843                 error = -EBUSY;
2844                 goto out;
2845         }
2846
2847         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2848                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2849                                 " interface\n");
2850                 error = -EBUSY;
2851                 goto out_free_class;
2852         }
2853
2854         error = driver_register(&idetape_driver.gen_driver);
2855         if (error)
2856                 goto out_free_driver;
2857
2858         return 0;
2859
2860 out_free_driver:
2861         driver_unregister(&idetape_driver.gen_driver);
2862 out_free_class:
2863         class_destroy(idetape_sysfs_class);
2864 out:
2865         return error;
2866 }
2867
2868 MODULE_ALIAS("ide:*m-tape*");
2869 module_init(idetape_init);
2870 module_exit(idetape_exit);
2871 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2872 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2873 MODULE_LICENSE("GPL");