ide: unify conversion macros
[linux-2.6] / 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 DRV_NAME "ide-tape"
19
20 #define IDETAPE_VERSION "1.20"
21
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/kernel.h>
26 #include <linux/delay.h>
27 #include <linux/timer.h>
28 #include <linux/mm.h>
29 #include <linux/interrupt.h>
30 #include <linux/jiffies.h>
31 #include <linux/major.h>
32 #include <linux/errno.h>
33 #include <linux/genhd.h>
34 #include <linux/slab.h>
35 #include <linux/pci.h>
36 #include <linux/ide.h>
37 #include <linux/smp_lock.h>
38 #include <linux/completion.h>
39 #include <linux/bitops.h>
40 #include <linux/mutex.h>
41 #include <scsi/scsi.h>
42
43 #include <asm/byteorder.h>
44 #include <linux/irq.h>
45 #include <linux/uaccess.h>
46 #include <linux/io.h>
47 #include <asm/unaligned.h>
48 #include <linux/mtio.h>
49
50 enum {
51         /* output errors only */
52         DBG_ERR =               (1 << 0),
53         /* output all sense key/asc */
54         DBG_SENSE =             (1 << 1),
55         /* info regarding all chrdev-related procedures */
56         DBG_CHRDEV =            (1 << 2),
57         /* all remaining procedures */
58         DBG_PROCS =             (1 << 3),
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  * The following parameter is used to select the point in the internal tape fifo
85  * in which we will start to refill the buffer. Decreasing the following
86  * parameter will improve the system's latency and interactive response, while
87  * using a high value might improve system throughput.
88  */
89 #define IDETAPE_FIFO_THRESHOLD          2
90
91 /*
92  * DSC polling parameters.
93  *
94  * Polling for DSC (a single bit in the status register) is a very important
95  * function in ide-tape. There are two cases in which we poll for DSC:
96  *
97  * 1. Before a read/write packet command, to ensure that we can transfer data
98  * from/to the tape's data buffers, without causing an actual media access.
99  * In case the tape is not ready yet, we take out our request from the device
100  * request queue, so that ide.c could service requests from the other device
101  * on the same interface in the meantime.
102  *
103  * 2. After the successful initialization of a "media access packet command",
104  * which is a command that can take a long time to complete (the interval can
105  * range from several seconds to even an hour). Again, we postpone our request
106  * in the middle to free the bus for the other device. The polling frequency
107  * here should be lower than the read/write frequency since those media access
108  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
109  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
110  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
111  *
112  * We also set a timeout for the timer, in case something goes wrong. The
113  * timeout should be longer then the maximum execution time of a tape operation.
114  */
115
116 /* DSC timings. */
117 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
118 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
119 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
120 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
121 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
122 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
123 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
124
125 /*************************** End of tunable parameters ***********************/
126
127 /* tape directions */
128 enum {
129         IDETAPE_DIR_NONE  = (1 << 0),
130         IDETAPE_DIR_READ  = (1 << 1),
131         IDETAPE_DIR_WRITE = (1 << 2),
132 };
133
134 struct idetape_bh {
135         u32 b_size;
136         atomic_t b_count;
137         struct idetape_bh *b_reqnext;
138         char *b_data;
139 };
140
141 /* Tape door status */
142 #define DOOR_UNLOCKED                   0
143 #define DOOR_LOCKED                     1
144 #define DOOR_EXPLICITLY_LOCKED          2
145
146 /* Some defines for the SPACE command */
147 #define IDETAPE_SPACE_OVER_FILEMARK     1
148 #define IDETAPE_SPACE_TO_EOD            3
149
150 /* Some defines for the LOAD UNLOAD command */
151 #define IDETAPE_LU_LOAD_MASK            1
152 #define IDETAPE_LU_RETENSION_MASK       2
153 #define IDETAPE_LU_EOT_MASK             4
154
155 /* Error codes returned in rq->errors to the higher part of the driver. */
156 #define IDETAPE_ERROR_GENERAL           101
157 #define IDETAPE_ERROR_FILEMARK          102
158 #define IDETAPE_ERROR_EOD               103
159
160 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
161 #define IDETAPE_BLOCK_DESCRIPTOR        0
162 #define IDETAPE_CAPABILITIES_PAGE       0x2a
163
164 /*
165  * Most of our global data which we need to save even as we leave the driver due
166  * to an interrupt or a timer event is stored in the struct defined below.
167  */
168 typedef struct ide_tape_obj {
169         ide_drive_t     *drive;
170         ide_driver_t    *driver;
171         struct gendisk  *disk;
172         struct kref     kref;
173
174         /*
175          *      failed_pc points to the last failed packet command, or contains
176          *      NULL if we do not need to retry any packet command. This is
177          *      required since an additional packet command is needed before the
178          *      retry, to get detailed information on what went wrong.
179          */
180         /* Last failed packet command */
181         struct ide_atapi_pc *failed_pc;
182         /* used by REQ_IDETAPE_{READ,WRITE} requests */
183         struct ide_atapi_pc queued_pc;
184
185         /*
186          * DSC polling variables.
187          *
188          * While polling for DSC we use postponed_rq to postpone the current
189          * request so that ide.c will be able to service pending requests on the
190          * other device. Note that at most we will have only one DSC (usually
191          * data transfer) request in the device request queue.
192          */
193         struct request *postponed_rq;
194         /* The time in which we started polling for DSC */
195         unsigned long dsc_polling_start;
196         /* Timer used to poll for dsc */
197         struct timer_list dsc_timer;
198         /* Read/Write dsc polling frequency */
199         unsigned long best_dsc_rw_freq;
200         unsigned long dsc_poll_freq;
201         unsigned long dsc_timeout;
202
203         /* Read position information */
204         u8 partition;
205         /* Current block */
206         unsigned int first_frame;
207
208         /* Last error information */
209         u8 sense_key, asc, ascq;
210
211         /* Character device operation */
212         unsigned int minor;
213         /* device name */
214         char name[4];
215         /* Current character device data transfer direction */
216         u8 chrdev_dir;
217
218         /* tape block size, usually 512 or 1024 bytes */
219         unsigned short blk_size;
220         int user_bs_factor;
221
222         /* Copy of the tape's Capabilities and Mechanical Page */
223         u8 caps[20];
224
225         /*
226          * Active data transfer request parameters.
227          *
228          * At most, there is only one ide-tape originated data transfer request
229          * in the device request queue. This allows ide.c to easily service
230          * requests from the other device when we postpone our active request.
231          */
232
233         /* Data buffer size chosen based on the tape's recommendation */
234         int buffer_size;
235         /* merge buffer */
236         struct idetape_bh *merge_bh;
237         /* size of the merge buffer */
238         int merge_bh_size;
239         /* pointer to current buffer head within the merge buffer */
240         struct idetape_bh *bh;
241         char *b_data;
242         int b_count;
243
244         int pages_per_buffer;
245         /* Wasted space in each stage */
246         int excess_bh_size;
247
248         /* protects the ide-tape queue */
249         spinlock_t lock;
250
251         /* Measures average tape speed */
252         unsigned long avg_time;
253         int avg_size;
254         int avg_speed;
255
256         /* the door is currently locked */
257         int door_locked;
258         /* the tape hardware is write protected */
259         char drv_write_prot;
260         /* the tape is write protected (hardware or opened as read-only) */
261         char write_prot;
262
263         u32 debug_mask;
264 } idetape_tape_t;
265
266 static DEFINE_MUTEX(idetape_ref_mutex);
267
268 static struct class *idetape_sysfs_class;
269
270 static void ide_tape_release(struct kref *);
271
272 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
273 {
274         struct ide_tape_obj *tape = NULL;
275
276         mutex_lock(&idetape_ref_mutex);
277         tape = ide_drv_g(disk, ide_tape_obj);
278         if (tape) {
279                 if (ide_device_get(tape->drive))
280                         tape = NULL;
281                 else
282                         kref_get(&tape->kref);
283         }
284         mutex_unlock(&idetape_ref_mutex);
285         return tape;
286 }
287
288 static void ide_tape_put(struct ide_tape_obj *tape)
289 {
290         ide_drive_t *drive = tape->drive;
291
292         mutex_lock(&idetape_ref_mutex);
293         kref_put(&tape->kref, ide_tape_release);
294         ide_device_put(drive);
295         mutex_unlock(&idetape_ref_mutex);
296 }
297
298 /*
299  * The variables below are used for the character device interface. Additional
300  * state variables are defined in our ide_drive_t structure.
301  */
302 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
303
304 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
305 {
306         struct ide_tape_obj *tape = NULL;
307
308         mutex_lock(&idetape_ref_mutex);
309         tape = idetape_devs[i];
310         if (tape)
311                 kref_get(&tape->kref);
312         mutex_unlock(&idetape_ref_mutex);
313         return tape;
314 }
315
316 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
317                                   unsigned int bcount)
318 {
319         struct idetape_bh *bh = pc->bh;
320         int count;
321
322         while (bcount) {
323                 if (bh == NULL) {
324                         printk(KERN_ERR "ide-tape: bh == NULL in "
325                                 "idetape_input_buffers\n");
326                         ide_pad_transfer(drive, 0, bcount);
327                         return;
328                 }
329                 count = min(
330                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
331                         bcount);
332                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
333                                         atomic_read(&bh->b_count), count);
334                 bcount -= count;
335                 atomic_add(count, &bh->b_count);
336                 if (atomic_read(&bh->b_count) == bh->b_size) {
337                         bh = bh->b_reqnext;
338                         if (bh)
339                                 atomic_set(&bh->b_count, 0);
340                 }
341         }
342         pc->bh = bh;
343 }
344
345 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
346                                    unsigned int bcount)
347 {
348         struct idetape_bh *bh = pc->bh;
349         int count;
350
351         while (bcount) {
352                 if (bh == NULL) {
353                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
354                                         __func__);
355                         return;
356                 }
357                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
358                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
359                 bcount -= count;
360                 pc->b_data += count;
361                 pc->b_count -= count;
362                 if (!pc->b_count) {
363                         bh = bh->b_reqnext;
364                         pc->bh = bh;
365                         if (bh) {
366                                 pc->b_data = bh->b_data;
367                                 pc->b_count = atomic_read(&bh->b_count);
368                         }
369                 }
370         }
371 }
372
373 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
374 {
375         struct idetape_bh *bh = pc->bh;
376         int count;
377         unsigned int bcount = pc->xferred;
378
379         if (pc->flags & PC_FLAG_WRITING)
380                 return;
381         while (bcount) {
382                 if (bh == NULL) {
383                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
384                                         __func__);
385                         return;
386                 }
387                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
388                 atomic_set(&bh->b_count, count);
389                 if (atomic_read(&bh->b_count) == bh->b_size)
390                         bh = bh->b_reqnext;
391                 bcount -= count;
392         }
393         pc->bh = bh;
394 }
395
396 /*
397  * called on each failed packet command retry to analyze the request sense. We
398  * currently do not utilize this information.
399  */
400 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
401 {
402         idetape_tape_t *tape = drive->driver_data;
403         struct ide_atapi_pc *pc = tape->failed_pc;
404
405         tape->sense_key = sense[2] & 0xF;
406         tape->asc       = sense[12];
407         tape->ascq      = sense[13];
408
409         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
410                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
411
412         /* Correct pc->xferred by asking the tape.       */
413         if (pc->flags & PC_FLAG_DMA_ERROR) {
414                 pc->xferred = pc->req_xfer -
415                         tape->blk_size *
416                         get_unaligned_be32(&sense[3]);
417                 idetape_update_buffers(drive, pc);
418         }
419
420         /*
421          * If error was the result of a zero-length read or write command,
422          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
423          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
424          */
425         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
426             /* length == 0 */
427             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
428                 if (tape->sense_key == 5) {
429                         /* don't report an error, everything's ok */
430                         pc->error = 0;
431                         /* don't retry read/write */
432                         pc->flags |= PC_FLAG_ABORT;
433                 }
434         }
435         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
436                 pc->error = IDETAPE_ERROR_FILEMARK;
437                 pc->flags |= PC_FLAG_ABORT;
438         }
439         if (pc->c[0] == WRITE_6) {
440                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
441                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
442                         pc->error = IDETAPE_ERROR_EOD;
443                         pc->flags |= PC_FLAG_ABORT;
444                 }
445         }
446         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
447                 if (tape->sense_key == 8) {
448                         pc->error = IDETAPE_ERROR_EOD;
449                         pc->flags |= PC_FLAG_ABORT;
450                 }
451                 if (!(pc->flags & PC_FLAG_ABORT) &&
452                     pc->xferred)
453                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
454         }
455 }
456
457 /* Free data buffers completely. */
458 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
459 {
460         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
461
462         while (bh) {
463                 u32 size = bh->b_size;
464
465                 while (size) {
466                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
467
468                         if (bh->b_data)
469                                 free_pages((unsigned long)bh->b_data, order);
470
471                         size &= (order-1);
472                         bh->b_data += (1 << order) * PAGE_SIZE;
473                 }
474                 prev_bh = bh;
475                 bh = bh->b_reqnext;
476                 kfree(prev_bh);
477         }
478 }
479
480 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
481 {
482         struct request *rq = HWGROUP(drive)->rq;
483         idetape_tape_t *tape = drive->driver_data;
484         unsigned long flags;
485         int error;
486
487         debug_log(DBG_PROCS, "Enter %s\n", __func__);
488
489         switch (uptodate) {
490         case 0: error = IDETAPE_ERROR_GENERAL; break;
491         case 1: error = 0; break;
492         default: error = uptodate;
493         }
494         rq->errors = error;
495         if (error)
496                 tape->failed_pc = NULL;
497
498         if (!blk_special_request(rq)) {
499                 ide_end_request(drive, uptodate, nr_sects);
500                 return 0;
501         }
502
503         spin_lock_irqsave(&tape->lock, flags);
504
505         ide_end_drive_cmd(drive, 0, 0);
506
507         spin_unlock_irqrestore(&tape->lock, flags);
508         return 0;
509 }
510
511 static void ide_tape_handle_dsc(ide_drive_t *);
512
513 static void ide_tape_callback(ide_drive_t *drive, int dsc)
514 {
515         idetape_tape_t *tape = drive->driver_data;
516         struct ide_atapi_pc *pc = drive->pc;
517         int uptodate = pc->error ? 0 : 1;
518
519         debug_log(DBG_PROCS, "Enter %s\n", __func__);
520
521         if (dsc)
522                 ide_tape_handle_dsc(drive);
523
524         if (tape->failed_pc == pc)
525                 tape->failed_pc = NULL;
526
527         if (pc->c[0] == REQUEST_SENSE) {
528                 if (uptodate)
529                         idetape_analyze_error(drive, pc->buf);
530                 else
531                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
532                                         "itself - Aborting request!\n");
533         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
534                 struct request *rq = drive->hwif->hwgroup->rq;
535                 int blocks = pc->xferred / tape->blk_size;
536
537                 tape->avg_size += blocks * tape->blk_size;
538
539                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
540                         tape->avg_speed = tape->avg_size * HZ /
541                                 (jiffies - tape->avg_time) / 1024;
542                         tape->avg_size = 0;
543                         tape->avg_time = jiffies;
544                 }
545
546                 tape->first_frame += blocks;
547                 rq->current_nr_sectors -= blocks;
548
549                 if (pc->error)
550                         uptodate = pc->error;
551         } else if (pc->c[0] == READ_POSITION && uptodate) {
552                 u8 *readpos = pc->buf;
553
554                 debug_log(DBG_SENSE, "BOP - %s\n",
555                                 (readpos[0] & 0x80) ? "Yes" : "No");
556                 debug_log(DBG_SENSE, "EOP - %s\n",
557                                 (readpos[0] & 0x40) ? "Yes" : "No");
558
559                 if (readpos[0] & 0x4) {
560                         printk(KERN_INFO "ide-tape: Block location is unknown"
561                                          "to the tape\n");
562                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
563                         uptodate = 0;
564                 } else {
565                         debug_log(DBG_SENSE, "Block Location - %u\n",
566                                         be32_to_cpup((__be32 *)&readpos[4]));
567
568                         tape->partition = readpos[1];
569                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
570                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
571                 }
572         }
573
574         idetape_end_request(drive, uptodate, 0);
575 }
576
577 /*
578  * Postpone the current request so that ide.c will be able to service requests
579  * from another device on the same hwgroup while we are polling for DSC.
580  */
581 static void idetape_postpone_request(ide_drive_t *drive)
582 {
583         idetape_tape_t *tape = drive->driver_data;
584
585         debug_log(DBG_PROCS, "Enter %s\n", __func__);
586
587         tape->postponed_rq = HWGROUP(drive)->rq;
588         ide_stall_queue(drive, tape->dsc_poll_freq);
589 }
590
591 static void ide_tape_handle_dsc(ide_drive_t *drive)
592 {
593         idetape_tape_t *tape = drive->driver_data;
594
595         /* Media access command */
596         tape->dsc_polling_start = jiffies;
597         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
598         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
599         /* Allow ide.c to handle other requests */
600         idetape_postpone_request(drive);
601 }
602
603 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
604                                 unsigned int bcount, int write)
605 {
606         if (write)
607                 idetape_output_buffers(drive, pc, bcount);
608         else
609                 idetape_input_buffers(drive, pc, bcount);
610
611         return bcount;
612 }
613
614 /*
615  * Packet Command Interface
616  *
617  * The current Packet Command is available in drive->pc, and will not change
618  * until we finish handling it. Each packet command is associated with a
619  * callback function that will be called when the command is finished.
620  *
621  * The handling will be done in three stages:
622  *
623  * 1. idetape_issue_pc will send the packet command to the drive, and will set
624  * the interrupt handler to ide_pc_intr.
625  *
626  * 2. On each interrupt, ide_pc_intr will be called. This step will be
627  * repeated until the device signals us that no more interrupts will be issued.
628  *
629  * 3. ATAPI Tape media access commands have immediate status with a delayed
630  * process. In case of a successful initiation of a media access packet command,
631  * the DSC bit will be set when the actual execution of the command is finished.
632  * Since the tape drive will not issue an interrupt, we have to poll for this
633  * event. In this case, we define the request as "low priority request" by
634  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
635  * exit the driver.
636  *
637  * ide.c will then give higher priority to requests which originate from the
638  * other device, until will change rq_status to RQ_ACTIVE.
639  *
640  * 4. When the packet command is finished, it will be checked for errors.
641  *
642  * 5. In case an error was found, we queue a request sense packet command in
643  * front of the request queue and retry the operation up to
644  * IDETAPE_MAX_PC_RETRIES times.
645  *
646  * 6. In case no error was found, or we decided to give up and not to retry
647  * again, the callback function will be called and then we will handle the next
648  * request.
649  */
650
651 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
652                 struct ide_atapi_pc *pc)
653 {
654         idetape_tape_t *tape = drive->driver_data;
655
656         if (drive->pc->c[0] == REQUEST_SENSE &&
657             pc->c[0] == REQUEST_SENSE) {
658                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
659                         "Two request sense in serial were issued\n");
660         }
661
662         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
663                 tape->failed_pc = pc;
664
665         /* Set the current packet command */
666         drive->pc = pc;
667
668         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
669                 (pc->flags & PC_FLAG_ABORT)) {
670                 /*
671                  * We will "abort" retrying a packet command in case legitimate
672                  * error code was received (crossing a filemark, or end of the
673                  * media, for example).
674                  */
675                 if (!(pc->flags & PC_FLAG_ABORT)) {
676                         if (!(pc->c[0] == TEST_UNIT_READY &&
677                               tape->sense_key == 2 && tape->asc == 4 &&
678                              (tape->ascq == 1 || tape->ascq == 8))) {
679                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
680                                                 "pc = %2x, key = %2x, "
681                                                 "asc = %2x, ascq = %2x\n",
682                                                 tape->name, pc->c[0],
683                                                 tape->sense_key, tape->asc,
684                                                 tape->ascq);
685                         }
686                         /* Giving up */
687                         pc->error = IDETAPE_ERROR_GENERAL;
688                 }
689                 tape->failed_pc = NULL;
690                 drive->pc_callback(drive, 0);
691                 return ide_stopped;
692         }
693         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
694
695         pc->retries++;
696
697         return ide_issue_pc(drive, WAIT_TAPE_CMD, NULL);
698 }
699
700 /* A mode sense command is used to "sense" tape parameters. */
701 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
702 {
703         ide_init_pc(pc);
704         pc->c[0] = MODE_SENSE;
705         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
706                 /* DBD = 1 - Don't return block descriptors */
707                 pc->c[1] = 8;
708         pc->c[2] = page_code;
709         /*
710          * Changed pc->c[3] to 0 (255 will at best return unused info).
711          *
712          * For SCSI this byte is defined as subpage instead of high byte
713          * of length and some IDE drives seem to interpret it this way
714          * and return an error when 255 is used.
715          */
716         pc->c[3] = 0;
717         /* We will just discard data in that case */
718         pc->c[4] = 255;
719         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
720                 pc->req_xfer = 12;
721         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
722                 pc->req_xfer = 24;
723         else
724                 pc->req_xfer = 50;
725 }
726
727 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
728 {
729         ide_hwif_t *hwif = drive->hwif;
730         idetape_tape_t *tape = drive->driver_data;
731         struct ide_atapi_pc *pc = drive->pc;
732         u8 stat;
733
734         stat = hwif->tp_ops->read_status(hwif);
735
736         if (stat & ATA_DSC) {
737                 if (stat & ATA_ERR) {
738                         /* Error detected */
739                         if (pc->c[0] != TEST_UNIT_READY)
740                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
741                                                 tape->name);
742                         /* Retry operation */
743                         ide_retry_pc(drive, tape->disk);
744                         return ide_stopped;
745                 }
746                 pc->error = 0;
747         } else {
748                 pc->error = IDETAPE_ERROR_GENERAL;
749                 tape->failed_pc = NULL;
750         }
751         drive->pc_callback(drive, 0);
752         return ide_stopped;
753 }
754
755 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
756                                    struct ide_atapi_pc *pc, struct request *rq,
757                                    u8 opcode)
758 {
759         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
760         unsigned int length = rq->current_nr_sectors;
761
762         ide_init_pc(pc);
763         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
764         pc->c[1] = 1;
765         pc->bh = bh;
766         pc->buf = NULL;
767         pc->buf_size = length * tape->blk_size;
768         pc->req_xfer = pc->buf_size;
769         if (pc->req_xfer == tape->buffer_size)
770                 pc->flags |= PC_FLAG_DMA_OK;
771
772         if (opcode == READ_6) {
773                 pc->c[0] = READ_6;
774                 atomic_set(&bh->b_count, 0);
775         } else if (opcode == WRITE_6) {
776                 pc->c[0] = WRITE_6;
777                 pc->flags |= PC_FLAG_WRITING;
778                 pc->b_data = bh->b_data;
779                 pc->b_count = atomic_read(&bh->b_count);
780         }
781
782         memcpy(rq->cmd, pc->c, 12);
783 }
784
785 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
786                                           struct request *rq, sector_t block)
787 {
788         ide_hwif_t *hwif = drive->hwif;
789         idetape_tape_t *tape = drive->driver_data;
790         struct ide_atapi_pc *pc = NULL;
791         struct request *postponed_rq = tape->postponed_rq;
792         u8 stat;
793
794         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
795                         " current_nr_sectors: %u\n",
796                         (unsigned long long)rq->sector, rq->nr_sectors,
797                         rq->current_nr_sectors);
798
799         if (!blk_special_request(rq)) {
800                 /* We do not support buffer cache originated requests. */
801                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
802                         "request queue (%d)\n", drive->name, rq->cmd_type);
803                 ide_end_request(drive, 0, 0);
804                 return ide_stopped;
805         }
806
807         /* Retry a failed packet command */
808         if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
809                 pc = tape->failed_pc;
810                 goto out;
811         }
812
813         if (postponed_rq != NULL)
814                 if (rq != postponed_rq) {
815                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
816                                         "Two DSC requests were queued\n");
817                         idetape_end_request(drive, 0, 0);
818                         return ide_stopped;
819                 }
820
821         tape->postponed_rq = NULL;
822
823         /*
824          * If the tape is still busy, postpone our request and service
825          * the other device meanwhile.
826          */
827         stat = hwif->tp_ops->read_status(hwif);
828
829         if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
830                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
831
832         if (drive->post_reset == 1) {
833                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
834                 drive->post_reset = 0;
835         }
836
837         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
838             (stat & ATA_DSC) == 0) {
839                 if (postponed_rq == NULL) {
840                         tape->dsc_polling_start = jiffies;
841                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
842                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
843                 } else if (time_after(jiffies, tape->dsc_timeout)) {
844                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
845                                 tape->name);
846                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
847                                 idetape_media_access_finished(drive);
848                                 return ide_stopped;
849                         } else {
850                                 return ide_do_reset(drive);
851                         }
852                 } else if (time_after(jiffies,
853                                         tape->dsc_polling_start +
854                                         IDETAPE_DSC_MA_THRESHOLD))
855                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
856                 idetape_postpone_request(drive);
857                 return ide_stopped;
858         }
859         if (rq->cmd[13] & REQ_IDETAPE_READ) {
860                 pc = &tape->queued_pc;
861                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
862                 goto out;
863         }
864         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
865                 pc = &tape->queued_pc;
866                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
867                 goto out;
868         }
869         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
870                 pc = (struct ide_atapi_pc *) rq->buffer;
871                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
872                 rq->cmd[13] |= REQ_IDETAPE_PC2;
873                 goto out;
874         }
875         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
876                 idetape_media_access_finished(drive);
877                 return ide_stopped;
878         }
879         BUG();
880
881 out:
882         return idetape_issue_pc(drive, pc);
883 }
884
885 /*
886  * The function below uses __get_free_pages to allocate a data buffer of size
887  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
888  * much as possible.
889  *
890  * It returns a pointer to the newly allocated buffer, or NULL in case of
891  * failure.
892  */
893 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
894                                                   int full, int clear)
895 {
896         struct idetape_bh *prev_bh, *bh, *merge_bh;
897         int pages = tape->pages_per_buffer;
898         unsigned int order, b_allocd;
899         char *b_data = NULL;
900
901         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
902         bh = merge_bh;
903         if (bh == NULL)
904                 goto abort;
905
906         order = fls(pages) - 1;
907         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
908         if (!bh->b_data)
909                 goto abort;
910         b_allocd = (1 << order) * PAGE_SIZE;
911         pages &= (order-1);
912
913         if (clear)
914                 memset(bh->b_data, 0, b_allocd);
915         bh->b_reqnext = NULL;
916         bh->b_size = b_allocd;
917         atomic_set(&bh->b_count, full ? bh->b_size : 0);
918
919         while (pages) {
920                 order = fls(pages) - 1;
921                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
922                 if (!b_data)
923                         goto abort;
924                 b_allocd = (1 << order) * PAGE_SIZE;
925
926                 if (clear)
927                         memset(b_data, 0, b_allocd);
928
929                 /* newly allocated page frames below buffer header or ...*/
930                 if (bh->b_data == b_data + b_allocd) {
931                         bh->b_size += b_allocd;
932                         bh->b_data -= b_allocd;
933                         if (full)
934                                 atomic_add(b_allocd, &bh->b_count);
935                         continue;
936                 }
937                 /* they are above the header */
938                 if (b_data == bh->b_data + bh->b_size) {
939                         bh->b_size += b_allocd;
940                         if (full)
941                                 atomic_add(b_allocd, &bh->b_count);
942                         continue;
943                 }
944                 prev_bh = bh;
945                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
946                 if (!bh) {
947                         free_pages((unsigned long) b_data, order);
948                         goto abort;
949                 }
950                 bh->b_reqnext = NULL;
951                 bh->b_data = b_data;
952                 bh->b_size = b_allocd;
953                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
954                 prev_bh->b_reqnext = bh;
955
956                 pages &= (order-1);
957         }
958
959         bh->b_size -= tape->excess_bh_size;
960         if (full)
961                 atomic_sub(tape->excess_bh_size, &bh->b_count);
962         return merge_bh;
963 abort:
964         ide_tape_kfree_buffer(tape);
965         return NULL;
966 }
967
968 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
969                                         const char __user *buf, int n)
970 {
971         struct idetape_bh *bh = tape->bh;
972         int count;
973         int ret = 0;
974
975         while (n) {
976                 if (bh == NULL) {
977                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
978                                         __func__);
979                         return 1;
980                 }
981                 count = min((unsigned int)
982                                 (bh->b_size - atomic_read(&bh->b_count)),
983                                 (unsigned int)n);
984                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
985                                 count))
986                         ret = 1;
987                 n -= count;
988                 atomic_add(count, &bh->b_count);
989                 buf += count;
990                 if (atomic_read(&bh->b_count) == bh->b_size) {
991                         bh = bh->b_reqnext;
992                         if (bh)
993                                 atomic_set(&bh->b_count, 0);
994                 }
995         }
996         tape->bh = bh;
997         return ret;
998 }
999
1000 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1001                                       int n)
1002 {
1003         struct idetape_bh *bh = tape->bh;
1004         int count;
1005         int ret = 0;
1006
1007         while (n) {
1008                 if (bh == NULL) {
1009                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1010                                         __func__);
1011                         return 1;
1012                 }
1013                 count = min(tape->b_count, n);
1014                 if  (copy_to_user(buf, tape->b_data, count))
1015                         ret = 1;
1016                 n -= count;
1017                 tape->b_data += count;
1018                 tape->b_count -= count;
1019                 buf += count;
1020                 if (!tape->b_count) {
1021                         bh = bh->b_reqnext;
1022                         tape->bh = bh;
1023                         if (bh) {
1024                                 tape->b_data = bh->b_data;
1025                                 tape->b_count = atomic_read(&bh->b_count);
1026                         }
1027                 }
1028         }
1029         return ret;
1030 }
1031
1032 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1033 {
1034         struct idetape_bh *bh = tape->merge_bh;
1035         tape->bh = tape->merge_bh;
1036
1037         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1038                 atomic_set(&bh->b_count, 0);
1039         else {
1040                 tape->b_data = bh->b_data;
1041                 tape->b_count = atomic_read(&bh->b_count);
1042         }
1043 }
1044
1045 /*
1046  * Write a filemark if write_filemark=1. Flush the device buffers without
1047  * writing a filemark otherwise.
1048  */
1049 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1050                 struct ide_atapi_pc *pc, int write_filemark)
1051 {
1052         ide_init_pc(pc);
1053         pc->c[0] = WRITE_FILEMARKS;
1054         pc->c[4] = write_filemark;
1055         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1056 }
1057
1058 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1059 {
1060         idetape_tape_t *tape = drive->driver_data;
1061         struct gendisk *disk = tape->disk;
1062         int load_attempted = 0;
1063
1064         /* Wait for the tape to become ready */
1065         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1066         timeout += jiffies;
1067         while (time_before(jiffies, timeout)) {
1068                 if (ide_do_test_unit_ready(drive, disk) == 0)
1069                         return 0;
1070                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1071                     || (tape->asc == 0x3A)) {
1072                         /* no media */
1073                         if (load_attempted)
1074                                 return -ENOMEDIUM;
1075                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1076                         load_attempted = 1;
1077                 /* not about to be ready */
1078                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1079                              (tape->ascq == 1 || tape->ascq == 8)))
1080                         return -EIO;
1081                 msleep(100);
1082         }
1083         return -EIO;
1084 }
1085
1086 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1087 {
1088         struct ide_tape_obj *tape = drive->driver_data;
1089         struct ide_atapi_pc pc;
1090         int rc;
1091
1092         idetape_create_write_filemark_cmd(drive, &pc, 0);
1093         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1094         if (rc)
1095                 return rc;
1096         idetape_wait_ready(drive, 60 * 5 * HZ);
1097         return 0;
1098 }
1099
1100 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1101 {
1102         ide_init_pc(pc);
1103         pc->c[0] = READ_POSITION;
1104         pc->req_xfer = 20;
1105 }
1106
1107 static int idetape_read_position(ide_drive_t *drive)
1108 {
1109         idetape_tape_t *tape = drive->driver_data;
1110         struct ide_atapi_pc pc;
1111         int position;
1112
1113         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1114
1115         idetape_create_read_position_cmd(&pc);
1116         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1117                 return -1;
1118         position = tape->first_frame;
1119         return position;
1120 }
1121
1122 static void idetape_create_locate_cmd(ide_drive_t *drive,
1123                 struct ide_atapi_pc *pc,
1124                 unsigned int block, u8 partition, int skip)
1125 {
1126         ide_init_pc(pc);
1127         pc->c[0] = POSITION_TO_ELEMENT;
1128         pc->c[1] = 2;
1129         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1130         pc->c[8] = partition;
1131         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1132 }
1133
1134 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1135 {
1136         idetape_tape_t *tape = drive->driver_data;
1137
1138         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1139                 return;
1140
1141         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1142         tape->merge_bh_size = 0;
1143         if (tape->merge_bh != NULL) {
1144                 ide_tape_kfree_buffer(tape);
1145                 tape->merge_bh = NULL;
1146         }
1147
1148         tape->chrdev_dir = IDETAPE_DIR_NONE;
1149 }
1150
1151 /*
1152  * Position the tape to the requested block using the LOCATE packet command.
1153  * A READ POSITION command is then issued to check where we are positioned. Like
1154  * all higher level operations, we queue the commands at the tail of the request
1155  * queue and wait for their completion.
1156  */
1157 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1158                 u8 partition, int skip)
1159 {
1160         idetape_tape_t *tape = drive->driver_data;
1161         struct gendisk *disk = tape->disk;
1162         int retval;
1163         struct ide_atapi_pc pc;
1164
1165         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1166                 __ide_tape_discard_merge_buffer(drive);
1167         idetape_wait_ready(drive, 60 * 5 * HZ);
1168         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1169         retval = ide_queue_pc_tail(drive, disk, &pc);
1170         if (retval)
1171                 return (retval);
1172
1173         idetape_create_read_position_cmd(&pc);
1174         return ide_queue_pc_tail(drive, disk, &pc);
1175 }
1176
1177 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1178                                           int restore_position)
1179 {
1180         idetape_tape_t *tape = drive->driver_data;
1181         int seek, position;
1182
1183         __ide_tape_discard_merge_buffer(drive);
1184         if (restore_position) {
1185                 position = idetape_read_position(drive);
1186                 seek = position > 0 ? position : 0;
1187                 if (idetape_position_tape(drive, seek, 0, 0)) {
1188                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1189                                          " %s\n", tape->name, __func__);
1190                         return;
1191                 }
1192         }
1193 }
1194
1195 /*
1196  * Generate a read/write request for the block device interface and wait for it
1197  * to be serviced.
1198  */
1199 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1200                                  struct idetape_bh *bh)
1201 {
1202         idetape_tape_t *tape = drive->driver_data;
1203         struct request *rq;
1204         int ret, errors;
1205
1206         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1207
1208         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1209         rq->cmd_type = REQ_TYPE_SPECIAL;
1210         rq->cmd[13] = cmd;
1211         rq->rq_disk = tape->disk;
1212         rq->special = (void *)bh;
1213         rq->sector = tape->first_frame;
1214         rq->nr_sectors = blocks;
1215         rq->current_nr_sectors = blocks;
1216         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1217
1218         errors = rq->errors;
1219         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1220         blk_put_request(rq);
1221
1222         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1223                 return 0;
1224
1225         if (tape->merge_bh)
1226                 idetape_init_merge_buffer(tape);
1227         if (errors == IDETAPE_ERROR_GENERAL)
1228                 return -EIO;
1229         return ret;
1230 }
1231
1232 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1233 {
1234         ide_init_pc(pc);
1235         pc->c[0] = INQUIRY;
1236         pc->c[4] = 254;
1237         pc->req_xfer = 254;
1238 }
1239
1240 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1241                 struct ide_atapi_pc *pc)
1242 {
1243         ide_init_pc(pc);
1244         pc->c[0] = REZERO_UNIT;
1245         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1246 }
1247
1248 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1249 {
1250         ide_init_pc(pc);
1251         pc->c[0] = ERASE;
1252         pc->c[1] = 1;
1253         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1254 }
1255
1256 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1257 {
1258         ide_init_pc(pc);
1259         pc->c[0] = SPACE;
1260         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1261         pc->c[1] = cmd;
1262         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1263 }
1264
1265 /* Queue up a character device originated write request. */
1266 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1267 {
1268         idetape_tape_t *tape = drive->driver_data;
1269
1270         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1271
1272         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1273                                      blocks, tape->merge_bh);
1274 }
1275
1276 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1277 {
1278         idetape_tape_t *tape = drive->driver_data;
1279         int blocks, min;
1280         struct idetape_bh *bh;
1281
1282         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1283                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1284                                 " but we are not writing.\n");
1285                 return;
1286         }
1287         if (tape->merge_bh_size > tape->buffer_size) {
1288                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1289                 tape->merge_bh_size = tape->buffer_size;
1290         }
1291         if (tape->merge_bh_size) {
1292                 blocks = tape->merge_bh_size / tape->blk_size;
1293                 if (tape->merge_bh_size % tape->blk_size) {
1294                         unsigned int i;
1295
1296                         blocks++;
1297                         i = tape->blk_size - tape->merge_bh_size %
1298                                 tape->blk_size;
1299                         bh = tape->bh->b_reqnext;
1300                         while (bh) {
1301                                 atomic_set(&bh->b_count, 0);
1302                                 bh = bh->b_reqnext;
1303                         }
1304                         bh = tape->bh;
1305                         while (i) {
1306                                 if (bh == NULL) {
1307                                         printk(KERN_INFO "ide-tape: bug,"
1308                                                          " bh NULL\n");
1309                                         break;
1310                                 }
1311                                 min = min(i, (unsigned int)(bh->b_size -
1312                                                 atomic_read(&bh->b_count)));
1313                                 memset(bh->b_data + atomic_read(&bh->b_count),
1314                                                 0, min);
1315                                 atomic_add(min, &bh->b_count);
1316                                 i -= min;
1317                                 bh = bh->b_reqnext;
1318                         }
1319                 }
1320                 (void) idetape_add_chrdev_write_request(drive, blocks);
1321                 tape->merge_bh_size = 0;
1322         }
1323         if (tape->merge_bh != NULL) {
1324                 ide_tape_kfree_buffer(tape);
1325                 tape->merge_bh = NULL;
1326         }
1327         tape->chrdev_dir = IDETAPE_DIR_NONE;
1328 }
1329
1330 static int idetape_init_read(ide_drive_t *drive)
1331 {
1332         idetape_tape_t *tape = drive->driver_data;
1333         int bytes_read;
1334
1335         /* Initialize read operation */
1336         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1337                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1338                         ide_tape_flush_merge_buffer(drive);
1339                         idetape_flush_tape_buffers(drive);
1340                 }
1341                 if (tape->merge_bh || tape->merge_bh_size) {
1342                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1343                                          " 0 now\n");
1344                         tape->merge_bh_size = 0;
1345                 }
1346                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1347                 if (!tape->merge_bh)
1348                         return -ENOMEM;
1349                 tape->chrdev_dir = IDETAPE_DIR_READ;
1350
1351                 /*
1352                  * Issue a read 0 command to ensure that DSC handshake is
1353                  * switched from completion mode to buffer available mode.
1354                  * No point in issuing this if DSC overlap isn't supported, some
1355                  * drives (Seagate STT3401A) will return an error.
1356                  */
1357                 if (drive->dsc_overlap) {
1358                         bytes_read = idetape_queue_rw_tail(drive,
1359                                                         REQ_IDETAPE_READ, 0,
1360                                                         tape->merge_bh);
1361                         if (bytes_read < 0) {
1362                                 ide_tape_kfree_buffer(tape);
1363                                 tape->merge_bh = NULL;
1364                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1365                                 return bytes_read;
1366                         }
1367                 }
1368         }
1369
1370         return 0;
1371 }
1372
1373 /* called from idetape_chrdev_read() to service a chrdev read request. */
1374 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1375 {
1376         idetape_tape_t *tape = drive->driver_data;
1377
1378         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1379
1380         /* If we are at a filemark, return a read length of 0 */
1381         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1382                 return 0;
1383
1384         idetape_init_read(drive);
1385
1386         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1387                                      tape->merge_bh);
1388 }
1389
1390 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1391 {
1392         idetape_tape_t *tape = drive->driver_data;
1393         struct idetape_bh *bh;
1394         int blocks;
1395
1396         while (bcount) {
1397                 unsigned int count;
1398
1399                 bh = tape->merge_bh;
1400                 count = min(tape->buffer_size, bcount);
1401                 bcount -= count;
1402                 blocks = count / tape->blk_size;
1403                 while (count) {
1404                         atomic_set(&bh->b_count,
1405                                    min(count, (unsigned int)bh->b_size));
1406                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1407                         count -= atomic_read(&bh->b_count);
1408                         bh = bh->b_reqnext;
1409                 }
1410                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1411                                       tape->merge_bh);
1412         }
1413 }
1414
1415 /*
1416  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1417  * currently support only one partition.
1418  */
1419 static int idetape_rewind_tape(ide_drive_t *drive)
1420 {
1421         struct ide_tape_obj *tape = drive->driver_data;
1422         struct gendisk *disk = tape->disk;
1423         int retval;
1424         struct ide_atapi_pc pc;
1425
1426         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1427
1428         idetape_create_rewind_cmd(drive, &pc);
1429         retval = ide_queue_pc_tail(drive, disk, &pc);
1430         if (retval)
1431                 return retval;
1432
1433         idetape_create_read_position_cmd(&pc);
1434         retval = ide_queue_pc_tail(drive, disk, &pc);
1435         if (retval)
1436                 return retval;
1437         return 0;
1438 }
1439
1440 /* mtio.h compatible commands should be issued to the chrdev interface. */
1441 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1442                                 unsigned long arg)
1443 {
1444         idetape_tape_t *tape = drive->driver_data;
1445         void __user *argp = (void __user *)arg;
1446
1447         struct idetape_config {
1448                 int dsc_rw_frequency;
1449                 int dsc_media_access_frequency;
1450                 int nr_stages;
1451         } config;
1452
1453         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1454
1455         switch (cmd) {
1456         case 0x0340:
1457                 if (copy_from_user(&config, argp, sizeof(config)))
1458                         return -EFAULT;
1459                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1460                 break;
1461         case 0x0350:
1462                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1463                 config.nr_stages = 1;
1464                 if (copy_to_user(argp, &config, sizeof(config)))
1465                         return -EFAULT;
1466                 break;
1467         default:
1468                 return -EIO;
1469         }
1470         return 0;
1471 }
1472
1473 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1474                                         int mt_count)
1475 {
1476         idetape_tape_t *tape = drive->driver_data;
1477         struct gendisk *disk = tape->disk;
1478         struct ide_atapi_pc pc;
1479         int retval, count = 0;
1480         int sprev = !!(tape->caps[4] & 0x20);
1481
1482         if (mt_count == 0)
1483                 return 0;
1484         if (MTBSF == mt_op || MTBSFM == mt_op) {
1485                 if (!sprev)
1486                         return -EIO;
1487                 mt_count = -mt_count;
1488         }
1489
1490         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1491                 tape->merge_bh_size = 0;
1492                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1493                         ++count;
1494                 ide_tape_discard_merge_buffer(drive, 0);
1495         }
1496
1497         switch (mt_op) {
1498         case MTFSF:
1499         case MTBSF:
1500                 idetape_create_space_cmd(&pc, mt_count - count,
1501                                          IDETAPE_SPACE_OVER_FILEMARK);
1502                 return ide_queue_pc_tail(drive, disk, &pc);
1503         case MTFSFM:
1504         case MTBSFM:
1505                 if (!sprev)
1506                         return -EIO;
1507                 retval = idetape_space_over_filemarks(drive, MTFSF,
1508                                                       mt_count - count);
1509                 if (retval)
1510                         return retval;
1511                 count = (MTBSFM == mt_op ? 1 : -1);
1512                 return idetape_space_over_filemarks(drive, MTFSF, count);
1513         default:
1514                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1515                                 mt_op);
1516                 return -EIO;
1517         }
1518 }
1519
1520 /*
1521  * Our character device read / write functions.
1522  *
1523  * The tape is optimized to maximize throughput when it is transferring an
1524  * integral number of the "continuous transfer limit", which is a parameter of
1525  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1526  *
1527  * As of version 1.3 of the driver, the character device provides an abstract
1528  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1529  * same backup/restore procedure is supported. The driver will internally
1530  * convert the requests to the recommended transfer unit, so that an unmatch
1531  * between the user's block size to the recommended size will only result in a
1532  * (slightly) increased driver overhead, but will no longer hit performance.
1533  * This is not applicable to Onstream.
1534  */
1535 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1536                                    size_t count, loff_t *ppos)
1537 {
1538         struct ide_tape_obj *tape = file->private_data;
1539         ide_drive_t *drive = tape->drive;
1540         ssize_t bytes_read, temp, actually_read = 0, rc;
1541         ssize_t ret = 0;
1542         u16 ctl = *(u16 *)&tape->caps[12];
1543
1544         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1545
1546         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1547                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1548                         if (count > tape->blk_size &&
1549                             (count % tape->blk_size) == 0)
1550                                 tape->user_bs_factor = count / tape->blk_size;
1551         }
1552         rc = idetape_init_read(drive);
1553         if (rc < 0)
1554                 return rc;
1555         if (count == 0)
1556                 return (0);
1557         if (tape->merge_bh_size) {
1558                 actually_read = min((unsigned int)(tape->merge_bh_size),
1559                                     (unsigned int)count);
1560                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1561                         ret = -EFAULT;
1562                 buf += actually_read;
1563                 tape->merge_bh_size -= actually_read;
1564                 count -= actually_read;
1565         }
1566         while (count >= tape->buffer_size) {
1567                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1568                 if (bytes_read <= 0)
1569                         goto finish;
1570                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1571                         ret = -EFAULT;
1572                 buf += bytes_read;
1573                 count -= bytes_read;
1574                 actually_read += bytes_read;
1575         }
1576         if (count) {
1577                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1578                 if (bytes_read <= 0)
1579                         goto finish;
1580                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1581                 if (idetape_copy_stage_to_user(tape, buf, temp))
1582                         ret = -EFAULT;
1583                 actually_read += temp;
1584                 tape->merge_bh_size = bytes_read-temp;
1585         }
1586 finish:
1587         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1588                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1589
1590                 idetape_space_over_filemarks(drive, MTFSF, 1);
1591                 return 0;
1592         }
1593
1594         return ret ? ret : actually_read;
1595 }
1596
1597 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1598                                      size_t count, loff_t *ppos)
1599 {
1600         struct ide_tape_obj *tape = file->private_data;
1601         ide_drive_t *drive = tape->drive;
1602         ssize_t actually_written = 0;
1603         ssize_t ret = 0;
1604         u16 ctl = *(u16 *)&tape->caps[12];
1605
1606         /* The drive is write protected. */
1607         if (tape->write_prot)
1608                 return -EACCES;
1609
1610         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1611
1612         /* Initialize write operation */
1613         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1614                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1615                         ide_tape_discard_merge_buffer(drive, 1);
1616                 if (tape->merge_bh || tape->merge_bh_size) {
1617                         printk(KERN_ERR "ide-tape: merge_bh_size "
1618                                 "should be 0 now\n");
1619                         tape->merge_bh_size = 0;
1620                 }
1621                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1622                 if (!tape->merge_bh)
1623                         return -ENOMEM;
1624                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1625                 idetape_init_merge_buffer(tape);
1626
1627                 /*
1628                  * Issue a write 0 command to ensure that DSC handshake is
1629                  * switched from completion mode to buffer available mode. No
1630                  * point in issuing this if DSC overlap isn't supported, some
1631                  * drives (Seagate STT3401A) will return an error.
1632                  */
1633                 if (drive->dsc_overlap) {
1634                         ssize_t retval = idetape_queue_rw_tail(drive,
1635                                                         REQ_IDETAPE_WRITE, 0,
1636                                                         tape->merge_bh);
1637                         if (retval < 0) {
1638                                 ide_tape_kfree_buffer(tape);
1639                                 tape->merge_bh = NULL;
1640                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1641                                 return retval;
1642                         }
1643                 }
1644         }
1645         if (count == 0)
1646                 return (0);
1647         if (tape->merge_bh_size) {
1648                 if (tape->merge_bh_size >= tape->buffer_size) {
1649                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1650                         tape->merge_bh_size = 0;
1651                 }
1652                 actually_written = min((unsigned int)
1653                                 (tape->buffer_size - tape->merge_bh_size),
1654                                 (unsigned int)count);
1655                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1656                                 ret = -EFAULT;
1657                 buf += actually_written;
1658                 tape->merge_bh_size += actually_written;
1659                 count -= actually_written;
1660
1661                 if (tape->merge_bh_size == tape->buffer_size) {
1662                         ssize_t retval;
1663                         tape->merge_bh_size = 0;
1664                         retval = idetape_add_chrdev_write_request(drive, ctl);
1665                         if (retval <= 0)
1666                                 return (retval);
1667                 }
1668         }
1669         while (count >= tape->buffer_size) {
1670                 ssize_t retval;
1671                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1672                         ret = -EFAULT;
1673                 buf += tape->buffer_size;
1674                 count -= tape->buffer_size;
1675                 retval = idetape_add_chrdev_write_request(drive, ctl);
1676                 actually_written += tape->buffer_size;
1677                 if (retval <= 0)
1678                         return (retval);
1679         }
1680         if (count) {
1681                 actually_written += count;
1682                 if (idetape_copy_stage_from_user(tape, buf, count))
1683                         ret = -EFAULT;
1684                 tape->merge_bh_size += count;
1685         }
1686         return ret ? ret : actually_written;
1687 }
1688
1689 static int idetape_write_filemark(ide_drive_t *drive)
1690 {
1691         struct ide_tape_obj *tape = drive->driver_data;
1692         struct ide_atapi_pc pc;
1693
1694         /* Write a filemark */
1695         idetape_create_write_filemark_cmd(drive, &pc, 1);
1696         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1697                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1698                 return -EIO;
1699         }
1700         return 0;
1701 }
1702
1703 /*
1704  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1705  * requested.
1706  *
1707  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1708  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1709  * usually not supported.
1710  *
1711  * The following commands are currently not supported:
1712  *
1713  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1714  * MT_ST_WRITE_THRESHOLD.
1715  */
1716 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1717 {
1718         idetape_tape_t *tape = drive->driver_data;
1719         struct gendisk *disk = tape->disk;
1720         struct ide_atapi_pc pc;
1721         int i, retval;
1722
1723         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1724                         mt_op, mt_count);
1725
1726         switch (mt_op) {
1727         case MTFSF:
1728         case MTFSFM:
1729         case MTBSF:
1730         case MTBSFM:
1731                 if (!mt_count)
1732                         return 0;
1733                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1734         default:
1735                 break;
1736         }
1737
1738         switch (mt_op) {
1739         case MTWEOF:
1740                 if (tape->write_prot)
1741                         return -EACCES;
1742                 ide_tape_discard_merge_buffer(drive, 1);
1743                 for (i = 0; i < mt_count; i++) {
1744                         retval = idetape_write_filemark(drive);
1745                         if (retval)
1746                                 return retval;
1747                 }
1748                 return 0;
1749         case MTREW:
1750                 ide_tape_discard_merge_buffer(drive, 0);
1751                 if (idetape_rewind_tape(drive))
1752                         return -EIO;
1753                 return 0;
1754         case MTLOAD:
1755                 ide_tape_discard_merge_buffer(drive, 0);
1756                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1757         case MTUNLOAD:
1758         case MTOFFL:
1759                 /*
1760                  * If door is locked, attempt to unlock before
1761                  * attempting to eject.
1762                  */
1763                 if (tape->door_locked) {
1764                         if (!ide_set_media_lock(drive, disk, 0))
1765                                 tape->door_locked = DOOR_UNLOCKED;
1766                 }
1767                 ide_tape_discard_merge_buffer(drive, 0);
1768                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1769                 if (!retval)
1770                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1771                 return retval;
1772         case MTNOP:
1773                 ide_tape_discard_merge_buffer(drive, 0);
1774                 return idetape_flush_tape_buffers(drive);
1775         case MTRETEN:
1776                 ide_tape_discard_merge_buffer(drive, 0);
1777                 return ide_do_start_stop(drive, disk,
1778                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1779         case MTEOM:
1780                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1781                 return ide_queue_pc_tail(drive, disk, &pc);
1782         case MTERASE:
1783                 (void)idetape_rewind_tape(drive);
1784                 idetape_create_erase_cmd(&pc);
1785                 return ide_queue_pc_tail(drive, disk, &pc);
1786         case MTSETBLK:
1787                 if (mt_count) {
1788                         if (mt_count < tape->blk_size ||
1789                             mt_count % tape->blk_size)
1790                                 return -EIO;
1791                         tape->user_bs_factor = mt_count / tape->blk_size;
1792                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1793                 } else
1794                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1795                 return 0;
1796         case MTSEEK:
1797                 ide_tape_discard_merge_buffer(drive, 0);
1798                 return idetape_position_tape(drive,
1799                         mt_count * tape->user_bs_factor, tape->partition, 0);
1800         case MTSETPART:
1801                 ide_tape_discard_merge_buffer(drive, 0);
1802                 return idetape_position_tape(drive, 0, mt_count, 0);
1803         case MTFSR:
1804         case MTBSR:
1805         case MTLOCK:
1806                 retval = ide_set_media_lock(drive, disk, 1);
1807                 if (retval)
1808                         return retval;
1809                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1810                 return 0;
1811         case MTUNLOCK:
1812                 retval = ide_set_media_lock(drive, disk, 0);
1813                 if (retval)
1814                         return retval;
1815                 tape->door_locked = DOOR_UNLOCKED;
1816                 return 0;
1817         default:
1818                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1819                                 mt_op);
1820                 return -EIO;
1821         }
1822 }
1823
1824 /*
1825  * Our character device ioctls. General mtio.h magnetic io commands are
1826  * supported here, and not in the corresponding block interface. Our own
1827  * ide-tape ioctls are supported on both interfaces.
1828  */
1829 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1830                                 unsigned int cmd, unsigned long arg)
1831 {
1832         struct ide_tape_obj *tape = file->private_data;
1833         ide_drive_t *drive = tape->drive;
1834         struct mtop mtop;
1835         struct mtget mtget;
1836         struct mtpos mtpos;
1837         int block_offset = 0, position = tape->first_frame;
1838         void __user *argp = (void __user *)arg;
1839
1840         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1841
1842         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1843                 ide_tape_flush_merge_buffer(drive);
1844                 idetape_flush_tape_buffers(drive);
1845         }
1846         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1847                 block_offset = tape->merge_bh_size /
1848                         (tape->blk_size * tape->user_bs_factor);
1849                 position = idetape_read_position(drive);
1850                 if (position < 0)
1851                         return -EIO;
1852         }
1853         switch (cmd) {
1854         case MTIOCTOP:
1855                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1856                         return -EFAULT;
1857                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1858         case MTIOCGET:
1859                 memset(&mtget, 0, sizeof(struct mtget));
1860                 mtget.mt_type = MT_ISSCSI2;
1861                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1862                 mtget.mt_dsreg =
1863                         ((tape->blk_size * tape->user_bs_factor)
1864                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1865
1866                 if (tape->drv_write_prot)
1867                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1868
1869                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1870                         return -EFAULT;
1871                 return 0;
1872         case MTIOCPOS:
1873                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1874                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1875                         return -EFAULT;
1876                 return 0;
1877         default:
1878                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1879                         ide_tape_discard_merge_buffer(drive, 1);
1880                 return idetape_blkdev_ioctl(drive, cmd, arg);
1881         }
1882 }
1883
1884 /*
1885  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1886  * block size with the reported value.
1887  */
1888 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1889 {
1890         idetape_tape_t *tape = drive->driver_data;
1891         struct ide_atapi_pc pc;
1892
1893         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1894         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1895                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1896                 if (tape->blk_size == 0) {
1897                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1898                                             "block size, assuming 32k\n");
1899                         tape->blk_size = 32768;
1900                 }
1901                 return;
1902         }
1903         tape->blk_size = (pc.buf[4 + 5] << 16) +
1904                                 (pc.buf[4 + 6] << 8)  +
1905                                  pc.buf[4 + 7];
1906         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1907 }
1908
1909 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1910 {
1911         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1912         ide_drive_t *drive;
1913         idetape_tape_t *tape;
1914         int retval;
1915
1916         if (i >= MAX_HWIFS * MAX_DRIVES)
1917                 return -ENXIO;
1918
1919         lock_kernel();
1920         tape = ide_tape_chrdev_get(i);
1921         if (!tape) {
1922                 unlock_kernel();
1923                 return -ENXIO;
1924         }
1925
1926         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1927
1928         /*
1929          * We really want to do nonseekable_open(inode, filp); here, but some
1930          * versions of tar incorrectly call lseek on tapes and bail out if that
1931          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1932          */
1933         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1934
1935         drive = tape->drive;
1936
1937         filp->private_data = tape;
1938
1939         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1940                 retval = -EBUSY;
1941                 goto out_put_tape;
1942         }
1943
1944         retval = idetape_wait_ready(drive, 60 * HZ);
1945         if (retval) {
1946                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1947                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1948                 goto out_put_tape;
1949         }
1950
1951         idetape_read_position(drive);
1952         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1953                 (void)idetape_rewind_tape(drive);
1954
1955         /* Read block size and write protect status from drive. */
1956         ide_tape_get_bsize_from_bdesc(drive);
1957
1958         /* Set write protect flag if device is opened as read-only. */
1959         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1960                 tape->write_prot = 1;
1961         else
1962                 tape->write_prot = tape->drv_write_prot;
1963
1964         /* Make sure drive isn't write protected if user wants to write. */
1965         if (tape->write_prot) {
1966                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1967                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1968                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1969                         retval = -EROFS;
1970                         goto out_put_tape;
1971                 }
1972         }
1973
1974         /* Lock the tape drive door so user can't eject. */
1975         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1976                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1977                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1978                                 tape->door_locked = DOOR_LOCKED;
1979                 }
1980         }
1981         unlock_kernel();
1982         return 0;
1983
1984 out_put_tape:
1985         ide_tape_put(tape);
1986         unlock_kernel();
1987         return retval;
1988 }
1989
1990 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
1991 {
1992         idetape_tape_t *tape = drive->driver_data;
1993
1994         ide_tape_flush_merge_buffer(drive);
1995         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
1996         if (tape->merge_bh != NULL) {
1997                 idetape_pad_zeros(drive, tape->blk_size *
1998                                 (tape->user_bs_factor - 1));
1999                 ide_tape_kfree_buffer(tape);
2000                 tape->merge_bh = NULL;
2001         }
2002         idetape_write_filemark(drive);
2003         idetape_flush_tape_buffers(drive);
2004         idetape_flush_tape_buffers(drive);
2005 }
2006
2007 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2008 {
2009         struct ide_tape_obj *tape = filp->private_data;
2010         ide_drive_t *drive = tape->drive;
2011         unsigned int minor = iminor(inode);
2012
2013         lock_kernel();
2014         tape = drive->driver_data;
2015
2016         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2017
2018         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2019                 idetape_write_release(drive, minor);
2020         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2021                 if (minor < 128)
2022                         ide_tape_discard_merge_buffer(drive, 1);
2023         }
2024
2025         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2026                 (void) idetape_rewind_tape(drive);
2027         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2028                 if (tape->door_locked == DOOR_LOCKED) {
2029                         if (!ide_set_media_lock(drive, tape->disk, 0))
2030                                 tape->door_locked = DOOR_UNLOCKED;
2031                 }
2032         }
2033         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2034         ide_tape_put(tape);
2035         unlock_kernel();
2036         return 0;
2037 }
2038
2039 static void idetape_get_inquiry_results(ide_drive_t *drive)
2040 {
2041         idetape_tape_t *tape = drive->driver_data;
2042         struct ide_atapi_pc pc;
2043         char fw_rev[4], vendor_id[8], product_id[16];
2044
2045         idetape_create_inquiry_cmd(&pc);
2046         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2047                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2048                                 tape->name);
2049                 return;
2050         }
2051         memcpy(vendor_id, &pc.buf[8], 8);
2052         memcpy(product_id, &pc.buf[16], 16);
2053         memcpy(fw_rev, &pc.buf[32], 4);
2054
2055         ide_fixstring(vendor_id, 8, 0);
2056         ide_fixstring(product_id, 16, 0);
2057         ide_fixstring(fw_rev, 4, 0);
2058
2059         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2060                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2061 }
2062
2063 /*
2064  * Ask the tape about its various parameters. In particular, we will adjust our
2065  * data transfer buffer size to the recommended value as returned by the tape.
2066  */
2067 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2068 {
2069         idetape_tape_t *tape = drive->driver_data;
2070         struct ide_atapi_pc pc;
2071         u8 *caps;
2072         u8 speed, max_speed;
2073
2074         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2075         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2076                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2077                                 " some default values\n");
2078                 tape->blk_size = 512;
2079                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2080                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2081                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2082                 return;
2083         }
2084         caps = pc.buf + 4 + pc.buf[3];
2085
2086         /* convert to host order and save for later use */
2087         speed = be16_to_cpup((__be16 *)&caps[14]);
2088         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2089
2090         *(u16 *)&caps[8] = max_speed;
2091         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2092         *(u16 *)&caps[14] = speed;
2093         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2094
2095         if (!speed) {
2096                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2097                                 "(assuming 650KB/sec)\n", drive->name);
2098                 *(u16 *)&caps[14] = 650;
2099         }
2100         if (!max_speed) {
2101                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2102                                 "(assuming 650KB/sec)\n", drive->name);
2103                 *(u16 *)&caps[8] = 650;
2104         }
2105
2106         memcpy(&tape->caps, caps, 20);
2107
2108         /* device lacks locking support according to capabilities page */
2109         if ((caps[6] & 1) == 0)
2110                 drive->atapi_flags |= IDE_AFLAG_NO_DOORLOCK;
2111
2112         if (caps[7] & 0x02)
2113                 tape->blk_size = 512;
2114         else if (caps[7] & 0x04)
2115                 tape->blk_size = 1024;
2116 }
2117
2118 #ifdef CONFIG_IDE_PROC_FS
2119 #define ide_tape_devset_get(name, field) \
2120 static int get_##name(ide_drive_t *drive) \
2121 { \
2122         idetape_tape_t *tape = drive->driver_data; \
2123         return tape->field; \
2124 }
2125
2126 #define ide_tape_devset_set(name, field) \
2127 static int set_##name(ide_drive_t *drive, int arg) \
2128 { \
2129         idetape_tape_t *tape = drive->driver_data; \
2130         tape->field = arg; \
2131         return 0; \
2132 }
2133
2134 #define ide_tape_devset_rw_field(_name, _field) \
2135 ide_tape_devset_get(_name, _field) \
2136 ide_tape_devset_set(_name, _field) \
2137 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2138
2139 #define ide_tape_devset_r_field(_name, _field) \
2140 ide_tape_devset_get(_name, _field) \
2141 IDE_DEVSET(_name, 0, get_##_name, NULL)
2142
2143 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2144 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2145 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2146 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2147
2148 ide_devset_rw_field(dsc_overlap, dsc_overlap);
2149
2150 ide_tape_devset_rw_field(debug_mask, debug_mask);
2151 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2152
2153 ide_tape_devset_r_field(avg_speed, avg_speed);
2154 ide_tape_devset_r_field(speed, caps[14]);
2155 ide_tape_devset_r_field(buffer, caps[16]);
2156 ide_tape_devset_r_field(buffer_size, buffer_size);
2157
2158 static const struct ide_proc_devset idetape_settings[] = {
2159         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2160         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2161         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2162         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2163         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2164         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2165         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2166                                         mulf_tdsc, divf_tdsc),
2167         { 0 },
2168 };
2169 #endif
2170
2171 /*
2172  * The function below is called to:
2173  *
2174  * 1. Initialize our various state variables.
2175  * 2. Ask the tape for its capabilities.
2176  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2177  * is chosen based on the recommendation which we received in step 2.
2178  *
2179  * Note that at this point ide.c already assigned us an irq, so that we can
2180  * queue requests here and wait for their completion.
2181  */
2182 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2183 {
2184         unsigned long t;
2185         int speed;
2186         int buffer_size;
2187         u8 gcw[2];
2188         u16 *ctl = (u16 *)&tape->caps[12];
2189
2190         drive->pc_callback       = ide_tape_callback;
2191         drive->pc_update_buffers = idetape_update_buffers;
2192         drive->pc_io_buffers     = ide_tape_io_buffers;
2193
2194         spin_lock_init(&tape->lock);
2195         drive->dsc_overlap = 1;
2196         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2197                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2198                                  tape->name);
2199                 drive->dsc_overlap = 0;
2200         }
2201         /* Seagate Travan drives do not support DSC overlap. */
2202         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2203                 drive->dsc_overlap = 0;
2204         tape->minor = minor;
2205         tape->name[0] = 'h';
2206         tape->name[1] = 't';
2207         tape->name[2] = '0' + minor;
2208         tape->chrdev_dir = IDETAPE_DIR_NONE;
2209
2210         *((u16 *)&gcw) = drive->id[ATA_ID_CONFIG];
2211
2212         /* Command packet DRQ type */
2213         if (((gcw[0] & 0x60) >> 5) == 1)
2214                 set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
2215
2216         idetape_get_inquiry_results(drive);
2217         idetape_get_mode_sense_results(drive);
2218         ide_tape_get_bsize_from_bdesc(drive);
2219         tape->user_bs_factor = 1;
2220         tape->buffer_size = *ctl * tape->blk_size;
2221         while (tape->buffer_size > 0xffff) {
2222                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2223                 *ctl /= 2;
2224                 tape->buffer_size = *ctl * tape->blk_size;
2225         }
2226         buffer_size = tape->buffer_size;
2227         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2228         if (buffer_size % PAGE_SIZE) {
2229                 tape->pages_per_buffer++;
2230                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2231         }
2232
2233         /* select the "best" DSC read/write polling freq */
2234         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2235
2236         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2237
2238         /*
2239          * Ensure that the number we got makes sense; limit it within
2240          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2241          */
2242         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2243                                          IDETAPE_DSC_RW_MAX);
2244         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2245                 "%lums tDSC%s\n",
2246                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2247                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2248                 tape->buffer_size / 1024,
2249                 tape->best_dsc_rw_freq * 1000 / HZ,
2250                 drive->using_dma ? ", DMA":"");
2251
2252         ide_proc_register_driver(drive, tape->driver);
2253 }
2254
2255 static void ide_tape_remove(ide_drive_t *drive)
2256 {
2257         idetape_tape_t *tape = drive->driver_data;
2258
2259         ide_proc_unregister_driver(drive, tape->driver);
2260
2261         ide_unregister_region(tape->disk);
2262
2263         ide_tape_put(tape);
2264 }
2265
2266 static void ide_tape_release(struct kref *kref)
2267 {
2268         struct ide_tape_obj *tape = to_ide_drv(kref, ide_tape_obj);
2269         ide_drive_t *drive = tape->drive;
2270         struct gendisk *g = tape->disk;
2271
2272         BUG_ON(tape->merge_bh_size);
2273
2274         drive->dsc_overlap = 0;
2275         drive->driver_data = NULL;
2276         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2277         device_destroy(idetape_sysfs_class,
2278                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2279         idetape_devs[tape->minor] = NULL;
2280         g->private_data = NULL;
2281         put_disk(g);
2282         kfree(tape);
2283 }
2284
2285 #ifdef CONFIG_IDE_PROC_FS
2286 static int proc_idetape_read_name
2287         (char *page, char **start, off_t off, int count, int *eof, void *data)
2288 {
2289         ide_drive_t     *drive = (ide_drive_t *) data;
2290         idetape_tape_t  *tape = drive->driver_data;
2291         char            *out = page;
2292         int             len;
2293
2294         len = sprintf(out, "%s\n", tape->name);
2295         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2296 }
2297
2298 static ide_proc_entry_t idetape_proc[] = {
2299         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2300         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2301         { NULL, 0, NULL, NULL }
2302 };
2303 #endif
2304
2305 static int ide_tape_probe(ide_drive_t *);
2306
2307 static ide_driver_t idetape_driver = {
2308         .gen_driver = {
2309                 .owner          = THIS_MODULE,
2310                 .name           = "ide-tape",
2311                 .bus            = &ide_bus_type,
2312         },
2313         .probe                  = ide_tape_probe,
2314         .remove                 = ide_tape_remove,
2315         .version                = IDETAPE_VERSION,
2316         .media                  = ide_tape,
2317         .do_request             = idetape_do_request,
2318         .end_request            = idetape_end_request,
2319         .error                  = __ide_error,
2320 #ifdef CONFIG_IDE_PROC_FS
2321         .proc                   = idetape_proc,
2322         .settings               = idetape_settings,
2323 #endif
2324 };
2325
2326 /* Our character device supporting functions, passed to register_chrdev. */
2327 static const struct file_operations idetape_fops = {
2328         .owner          = THIS_MODULE,
2329         .read           = idetape_chrdev_read,
2330         .write          = idetape_chrdev_write,
2331         .ioctl          = idetape_chrdev_ioctl,
2332         .open           = idetape_chrdev_open,
2333         .release        = idetape_chrdev_release,
2334 };
2335
2336 static int idetape_open(struct inode *inode, struct file *filp)
2337 {
2338         struct gendisk *disk = inode->i_bdev->bd_disk;
2339         struct ide_tape_obj *tape;
2340
2341         tape = ide_tape_get(disk);
2342         if (!tape)
2343                 return -ENXIO;
2344
2345         return 0;
2346 }
2347
2348 static int idetape_release(struct inode *inode, struct file *filp)
2349 {
2350         struct gendisk *disk = inode->i_bdev->bd_disk;
2351         struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
2352
2353         ide_tape_put(tape);
2354
2355         return 0;
2356 }
2357
2358 static int idetape_ioctl(struct inode *inode, struct file *file,
2359                         unsigned int cmd, unsigned long arg)
2360 {
2361         struct block_device *bdev = inode->i_bdev;
2362         struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
2363         ide_drive_t *drive = tape->drive;
2364         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2365         if (err == -EINVAL)
2366                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2367         return err;
2368 }
2369
2370 static struct block_device_operations idetape_block_ops = {
2371         .owner          = THIS_MODULE,
2372         .open           = idetape_open,
2373         .release        = idetape_release,
2374         .ioctl          = idetape_ioctl,
2375 };
2376
2377 static int ide_tape_probe(ide_drive_t *drive)
2378 {
2379         idetape_tape_t *tape;
2380         struct gendisk *g;
2381         int minor;
2382
2383         if (!strstr("ide-tape", drive->driver_req))
2384                 goto failed;
2385
2386         if (drive->media != ide_tape)
2387                 goto failed;
2388
2389         if (drive->id_read == 1 && !ide_check_atapi_device(drive, DRV_NAME)) {
2390                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2391                                 " the driver\n", drive->name);
2392                 goto failed;
2393         }
2394         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2395         if (tape == NULL) {
2396                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2397                                 drive->name);
2398                 goto failed;
2399         }
2400
2401         g = alloc_disk(1 << PARTN_BITS);
2402         if (!g)
2403                 goto out_free_tape;
2404
2405         ide_init_disk(g, drive);
2406
2407         kref_init(&tape->kref);
2408
2409         tape->drive = drive;
2410         tape->driver = &idetape_driver;
2411         tape->disk = g;
2412
2413         g->private_data = &tape->driver;
2414
2415         drive->driver_data = tape;
2416
2417         mutex_lock(&idetape_ref_mutex);
2418         for (minor = 0; idetape_devs[minor]; minor++)
2419                 ;
2420         idetape_devs[minor] = tape;
2421         mutex_unlock(&idetape_ref_mutex);
2422
2423         idetape_setup(drive, tape, minor);
2424
2425         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2426                               MKDEV(IDETAPE_MAJOR, minor), NULL,
2427                               "%s", tape->name);
2428         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2429                               MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2430                               "n%s", tape->name);
2431
2432         g->fops = &idetape_block_ops;
2433         ide_register_region(g);
2434
2435         return 0;
2436
2437 out_free_tape:
2438         kfree(tape);
2439 failed:
2440         return -ENODEV;
2441 }
2442
2443 static void __exit idetape_exit(void)
2444 {
2445         driver_unregister(&idetape_driver.gen_driver);
2446         class_destroy(idetape_sysfs_class);
2447         unregister_chrdev(IDETAPE_MAJOR, "ht");
2448 }
2449
2450 static int __init idetape_init(void)
2451 {
2452         int error = 1;
2453         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2454         if (IS_ERR(idetape_sysfs_class)) {
2455                 idetape_sysfs_class = NULL;
2456                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2457                 error = -EBUSY;
2458                 goto out;
2459         }
2460
2461         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2462                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2463                                 " interface\n");
2464                 error = -EBUSY;
2465                 goto out_free_class;
2466         }
2467
2468         error = driver_register(&idetape_driver.gen_driver);
2469         if (error)
2470                 goto out_free_driver;
2471
2472         return 0;
2473
2474 out_free_driver:
2475         driver_unregister(&idetape_driver.gen_driver);
2476 out_free_class:
2477         class_destroy(idetape_sysfs_class);
2478 out:
2479         return error;
2480 }
2481
2482 MODULE_ALIAS("ide:*m-tape*");
2483 module_init(idetape_init);
2484 module_exit(idetape_exit);
2485 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2486 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2487 MODULE_LICENSE("GPL");