ide: remove CONFIG_BLK_DEV_IDE config option (take 2)
[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 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
271
272 #define ide_tape_g(disk) \
273         container_of((disk)->private_data, struct ide_tape_obj, driver)
274
275 static void ide_tape_release(struct kref *);
276
277 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
278 {
279         struct ide_tape_obj *tape = NULL;
280
281         mutex_lock(&idetape_ref_mutex);
282         tape = ide_tape_g(disk);
283         if (tape) {
284                 if (ide_device_get(tape->drive))
285                         tape = NULL;
286                 else
287                         kref_get(&tape->kref);
288         }
289         mutex_unlock(&idetape_ref_mutex);
290         return tape;
291 }
292
293 static void ide_tape_put(struct ide_tape_obj *tape)
294 {
295         ide_drive_t *drive = tape->drive;
296
297         mutex_lock(&idetape_ref_mutex);
298         kref_put(&tape->kref, ide_tape_release);
299         ide_device_put(drive);
300         mutex_unlock(&idetape_ref_mutex);
301 }
302
303 /*
304  * The variables below are used for the character device interface. Additional
305  * state variables are defined in our ide_drive_t structure.
306  */
307 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
308
309 #define ide_tape_f(file) ((file)->private_data)
310
311 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
312 {
313         struct ide_tape_obj *tape = NULL;
314
315         mutex_lock(&idetape_ref_mutex);
316         tape = idetape_devs[i];
317         if (tape)
318                 kref_get(&tape->kref);
319         mutex_unlock(&idetape_ref_mutex);
320         return tape;
321 }
322
323 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
324                                   unsigned int bcount)
325 {
326         struct idetape_bh *bh = pc->bh;
327         int count;
328
329         while (bcount) {
330                 if (bh == NULL) {
331                         printk(KERN_ERR "ide-tape: bh == NULL in "
332                                 "idetape_input_buffers\n");
333                         ide_pad_transfer(drive, 0, bcount);
334                         return;
335                 }
336                 count = min(
337                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
338                         bcount);
339                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
340                                         atomic_read(&bh->b_count), count);
341                 bcount -= count;
342                 atomic_add(count, &bh->b_count);
343                 if (atomic_read(&bh->b_count) == bh->b_size) {
344                         bh = bh->b_reqnext;
345                         if (bh)
346                                 atomic_set(&bh->b_count, 0);
347                 }
348         }
349         pc->bh = bh;
350 }
351
352 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
353                                    unsigned int bcount)
354 {
355         struct idetape_bh *bh = pc->bh;
356         int count;
357
358         while (bcount) {
359                 if (bh == NULL) {
360                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
361                                         __func__);
362                         return;
363                 }
364                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
365                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
366                 bcount -= count;
367                 pc->b_data += count;
368                 pc->b_count -= count;
369                 if (!pc->b_count) {
370                         bh = bh->b_reqnext;
371                         pc->bh = bh;
372                         if (bh) {
373                                 pc->b_data = bh->b_data;
374                                 pc->b_count = atomic_read(&bh->b_count);
375                         }
376                 }
377         }
378 }
379
380 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
381 {
382         struct idetape_bh *bh = pc->bh;
383         int count;
384         unsigned int bcount = pc->xferred;
385
386         if (pc->flags & PC_FLAG_WRITING)
387                 return;
388         while (bcount) {
389                 if (bh == NULL) {
390                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
391                                         __func__);
392                         return;
393                 }
394                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
395                 atomic_set(&bh->b_count, count);
396                 if (atomic_read(&bh->b_count) == bh->b_size)
397                         bh = bh->b_reqnext;
398                 bcount -= count;
399         }
400         pc->bh = bh;
401 }
402
403 /*
404  * called on each failed packet command retry to analyze the request sense. We
405  * currently do not utilize this information.
406  */
407 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
408 {
409         idetape_tape_t *tape = drive->driver_data;
410         struct ide_atapi_pc *pc = tape->failed_pc;
411
412         tape->sense_key = sense[2] & 0xF;
413         tape->asc       = sense[12];
414         tape->ascq      = sense[13];
415
416         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
417                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
418
419         /* Correct pc->xferred by asking the tape.       */
420         if (pc->flags & PC_FLAG_DMA_ERROR) {
421                 pc->xferred = pc->req_xfer -
422                         tape->blk_size *
423                         get_unaligned_be32(&sense[3]);
424                 idetape_update_buffers(drive, pc);
425         }
426
427         /*
428          * If error was the result of a zero-length read or write command,
429          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
430          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
431          */
432         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
433             /* length == 0 */
434             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
435                 if (tape->sense_key == 5) {
436                         /* don't report an error, everything's ok */
437                         pc->error = 0;
438                         /* don't retry read/write */
439                         pc->flags |= PC_FLAG_ABORT;
440                 }
441         }
442         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
443                 pc->error = IDETAPE_ERROR_FILEMARK;
444                 pc->flags |= PC_FLAG_ABORT;
445         }
446         if (pc->c[0] == WRITE_6) {
447                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
448                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
449                         pc->error = IDETAPE_ERROR_EOD;
450                         pc->flags |= PC_FLAG_ABORT;
451                 }
452         }
453         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
454                 if (tape->sense_key == 8) {
455                         pc->error = IDETAPE_ERROR_EOD;
456                         pc->flags |= PC_FLAG_ABORT;
457                 }
458                 if (!(pc->flags & PC_FLAG_ABORT) &&
459                     pc->xferred)
460                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
461         }
462 }
463
464 /* Free data buffers completely. */
465 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
466 {
467         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
468
469         while (bh) {
470                 u32 size = bh->b_size;
471
472                 while (size) {
473                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
474
475                         if (bh->b_data)
476                                 free_pages((unsigned long)bh->b_data, order);
477
478                         size &= (order-1);
479                         bh->b_data += (1 << order) * PAGE_SIZE;
480                 }
481                 prev_bh = bh;
482                 bh = bh->b_reqnext;
483                 kfree(prev_bh);
484         }
485 }
486
487 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
488 {
489         struct request *rq = HWGROUP(drive)->rq;
490         idetape_tape_t *tape = drive->driver_data;
491         unsigned long flags;
492         int error;
493
494         debug_log(DBG_PROCS, "Enter %s\n", __func__);
495
496         switch (uptodate) {
497         case 0: error = IDETAPE_ERROR_GENERAL; break;
498         case 1: error = 0; break;
499         default: error = uptodate;
500         }
501         rq->errors = error;
502         if (error)
503                 tape->failed_pc = NULL;
504
505         if (!blk_special_request(rq)) {
506                 ide_end_request(drive, uptodate, nr_sects);
507                 return 0;
508         }
509
510         spin_lock_irqsave(&tape->lock, flags);
511
512         ide_end_drive_cmd(drive, 0, 0);
513
514         spin_unlock_irqrestore(&tape->lock, flags);
515         return 0;
516 }
517
518 static void ide_tape_handle_dsc(ide_drive_t *);
519
520 static void ide_tape_callback(ide_drive_t *drive, int dsc)
521 {
522         idetape_tape_t *tape = drive->driver_data;
523         struct ide_atapi_pc *pc = drive->pc;
524         int uptodate = pc->error ? 0 : 1;
525
526         debug_log(DBG_PROCS, "Enter %s\n", __func__);
527
528         if (dsc)
529                 ide_tape_handle_dsc(drive);
530
531         if (tape->failed_pc == pc)
532                 tape->failed_pc = NULL;
533
534         if (pc->c[0] == REQUEST_SENSE) {
535                 if (uptodate)
536                         idetape_analyze_error(drive, pc->buf);
537                 else
538                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
539                                         "itself - Aborting request!\n");
540         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
541                 struct request *rq = drive->hwif->hwgroup->rq;
542                 int blocks = pc->xferred / tape->blk_size;
543
544                 tape->avg_size += blocks * tape->blk_size;
545
546                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
547                         tape->avg_speed = tape->avg_size * HZ /
548                                 (jiffies - tape->avg_time) / 1024;
549                         tape->avg_size = 0;
550                         tape->avg_time = jiffies;
551                 }
552
553                 tape->first_frame += blocks;
554                 rq->current_nr_sectors -= blocks;
555
556                 if (pc->error)
557                         uptodate = pc->error;
558         } else if (pc->c[0] == READ_POSITION && uptodate) {
559                 u8 *readpos = pc->buf;
560
561                 debug_log(DBG_SENSE, "BOP - %s\n",
562                                 (readpos[0] & 0x80) ? "Yes" : "No");
563                 debug_log(DBG_SENSE, "EOP - %s\n",
564                                 (readpos[0] & 0x40) ? "Yes" : "No");
565
566                 if (readpos[0] & 0x4) {
567                         printk(KERN_INFO "ide-tape: Block location is unknown"
568                                          "to the tape\n");
569                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
570                         uptodate = 0;
571                 } else {
572                         debug_log(DBG_SENSE, "Block Location - %u\n",
573                                         be32_to_cpup((__be32 *)&readpos[4]));
574
575                         tape->partition = readpos[1];
576                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
577                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
578                 }
579         }
580
581         idetape_end_request(drive, uptodate, 0);
582 }
583
584 /*
585  * Postpone the current request so that ide.c will be able to service requests
586  * from another device on the same hwgroup while we are polling for DSC.
587  */
588 static void idetape_postpone_request(ide_drive_t *drive)
589 {
590         idetape_tape_t *tape = drive->driver_data;
591
592         debug_log(DBG_PROCS, "Enter %s\n", __func__);
593
594         tape->postponed_rq = HWGROUP(drive)->rq;
595         ide_stall_queue(drive, tape->dsc_poll_freq);
596 }
597
598 static void ide_tape_handle_dsc(ide_drive_t *drive)
599 {
600         idetape_tape_t *tape = drive->driver_data;
601
602         /* Media access command */
603         tape->dsc_polling_start = jiffies;
604         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
605         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
606         /* Allow ide.c to handle other requests */
607         idetape_postpone_request(drive);
608 }
609
610 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
611                                 unsigned int bcount, int write)
612 {
613         if (write)
614                 idetape_output_buffers(drive, pc, bcount);
615         else
616                 idetape_input_buffers(drive, pc, bcount);
617
618         return bcount;
619 }
620
621 /*
622  * Packet Command Interface
623  *
624  * The current Packet Command is available in drive->pc, and will not change
625  * until we finish handling it. Each packet command is associated with a
626  * callback function that will be called when the command is finished.
627  *
628  * The handling will be done in three stages:
629  *
630  * 1. idetape_issue_pc will send the packet command to the drive, and will set
631  * the interrupt handler to ide_pc_intr.
632  *
633  * 2. On each interrupt, ide_pc_intr will be called. This step will be
634  * repeated until the device signals us that no more interrupts will be issued.
635  *
636  * 3. ATAPI Tape media access commands have immediate status with a delayed
637  * process. In case of a successful initiation of a media access packet command,
638  * the DSC bit will be set when the actual execution of the command is finished.
639  * Since the tape drive will not issue an interrupt, we have to poll for this
640  * event. In this case, we define the request as "low priority request" by
641  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
642  * exit the driver.
643  *
644  * ide.c will then give higher priority to requests which originate from the
645  * other device, until will change rq_status to RQ_ACTIVE.
646  *
647  * 4. When the packet command is finished, it will be checked for errors.
648  *
649  * 5. In case an error was found, we queue a request sense packet command in
650  * front of the request queue and retry the operation up to
651  * IDETAPE_MAX_PC_RETRIES times.
652  *
653  * 6. In case no error was found, or we decided to give up and not to retry
654  * again, the callback function will be called and then we will handle the next
655  * request.
656  */
657
658 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
659                 struct ide_atapi_pc *pc)
660 {
661         idetape_tape_t *tape = drive->driver_data;
662
663         if (drive->pc->c[0] == REQUEST_SENSE &&
664             pc->c[0] == REQUEST_SENSE) {
665                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
666                         "Two request sense in serial were issued\n");
667         }
668
669         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
670                 tape->failed_pc = pc;
671
672         /* Set the current packet command */
673         drive->pc = pc;
674
675         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
676                 (pc->flags & PC_FLAG_ABORT)) {
677                 /*
678                  * We will "abort" retrying a packet command in case legitimate
679                  * error code was received (crossing a filemark, or end of the
680                  * media, for example).
681                  */
682                 if (!(pc->flags & PC_FLAG_ABORT)) {
683                         if (!(pc->c[0] == TEST_UNIT_READY &&
684                               tape->sense_key == 2 && tape->asc == 4 &&
685                              (tape->ascq == 1 || tape->ascq == 8))) {
686                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
687                                                 "pc = %2x, key = %2x, "
688                                                 "asc = %2x, ascq = %2x\n",
689                                                 tape->name, pc->c[0],
690                                                 tape->sense_key, tape->asc,
691                                                 tape->ascq);
692                         }
693                         /* Giving up */
694                         pc->error = IDETAPE_ERROR_GENERAL;
695                 }
696                 tape->failed_pc = NULL;
697                 drive->pc_callback(drive, 0);
698                 return ide_stopped;
699         }
700         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
701
702         pc->retries++;
703
704         return ide_issue_pc(drive, WAIT_TAPE_CMD, NULL);
705 }
706
707 /* A mode sense command is used to "sense" tape parameters. */
708 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
709 {
710         ide_init_pc(pc);
711         pc->c[0] = MODE_SENSE;
712         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
713                 /* DBD = 1 - Don't return block descriptors */
714                 pc->c[1] = 8;
715         pc->c[2] = page_code;
716         /*
717          * Changed pc->c[3] to 0 (255 will at best return unused info).
718          *
719          * For SCSI this byte is defined as subpage instead of high byte
720          * of length and some IDE drives seem to interpret it this way
721          * and return an error when 255 is used.
722          */
723         pc->c[3] = 0;
724         /* We will just discard data in that case */
725         pc->c[4] = 255;
726         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
727                 pc->req_xfer = 12;
728         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
729                 pc->req_xfer = 24;
730         else
731                 pc->req_xfer = 50;
732 }
733
734 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
735 {
736         ide_hwif_t *hwif = drive->hwif;
737         idetape_tape_t *tape = drive->driver_data;
738         struct ide_atapi_pc *pc = drive->pc;
739         u8 stat;
740
741         stat = hwif->tp_ops->read_status(hwif);
742
743         if (stat & ATA_DSC) {
744                 if (stat & ATA_ERR) {
745                         /* Error detected */
746                         if (pc->c[0] != TEST_UNIT_READY)
747                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
748                                                 tape->name);
749                         /* Retry operation */
750                         ide_retry_pc(drive, tape->disk);
751                         return ide_stopped;
752                 }
753                 pc->error = 0;
754         } else {
755                 pc->error = IDETAPE_ERROR_GENERAL;
756                 tape->failed_pc = NULL;
757         }
758         drive->pc_callback(drive, 0);
759         return ide_stopped;
760 }
761
762 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
763                                    struct ide_atapi_pc *pc, struct request *rq,
764                                    u8 opcode)
765 {
766         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
767         unsigned int length = rq->current_nr_sectors;
768
769         ide_init_pc(pc);
770         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
771         pc->c[1] = 1;
772         pc->bh = bh;
773         pc->buf = NULL;
774         pc->buf_size = length * tape->blk_size;
775         pc->req_xfer = pc->buf_size;
776         if (pc->req_xfer == tape->buffer_size)
777                 pc->flags |= PC_FLAG_DMA_OK;
778
779         if (opcode == READ_6) {
780                 pc->c[0] = READ_6;
781                 atomic_set(&bh->b_count, 0);
782         } else if (opcode == WRITE_6) {
783                 pc->c[0] = WRITE_6;
784                 pc->flags |= PC_FLAG_WRITING;
785                 pc->b_data = bh->b_data;
786                 pc->b_count = atomic_read(&bh->b_count);
787         }
788
789         memcpy(rq->cmd, pc->c, 12);
790 }
791
792 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
793                                           struct request *rq, sector_t block)
794 {
795         ide_hwif_t *hwif = drive->hwif;
796         idetape_tape_t *tape = drive->driver_data;
797         struct ide_atapi_pc *pc = NULL;
798         struct request *postponed_rq = tape->postponed_rq;
799         u8 stat;
800
801         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
802                         " current_nr_sectors: %u\n",
803                         (unsigned long long)rq->sector, rq->nr_sectors,
804                         rq->current_nr_sectors);
805
806         if (!blk_special_request(rq)) {
807                 /* We do not support buffer cache originated requests. */
808                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
809                         "request queue (%d)\n", drive->name, rq->cmd_type);
810                 ide_end_request(drive, 0, 0);
811                 return ide_stopped;
812         }
813
814         /* Retry a failed packet command */
815         if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
816                 pc = tape->failed_pc;
817                 goto out;
818         }
819
820         if (postponed_rq != NULL)
821                 if (rq != postponed_rq) {
822                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
823                                         "Two DSC requests were queued\n");
824                         idetape_end_request(drive, 0, 0);
825                         return ide_stopped;
826                 }
827
828         tape->postponed_rq = NULL;
829
830         /*
831          * If the tape is still busy, postpone our request and service
832          * the other device meanwhile.
833          */
834         stat = hwif->tp_ops->read_status(hwif);
835
836         if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
837                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
838
839         if (drive->post_reset == 1) {
840                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
841                 drive->post_reset = 0;
842         }
843
844         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
845             (stat & ATA_DSC) == 0) {
846                 if (postponed_rq == NULL) {
847                         tape->dsc_polling_start = jiffies;
848                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
849                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
850                 } else if (time_after(jiffies, tape->dsc_timeout)) {
851                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
852                                 tape->name);
853                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
854                                 idetape_media_access_finished(drive);
855                                 return ide_stopped;
856                         } else {
857                                 return ide_do_reset(drive);
858                         }
859                 } else if (time_after(jiffies,
860                                         tape->dsc_polling_start +
861                                         IDETAPE_DSC_MA_THRESHOLD))
862                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
863                 idetape_postpone_request(drive);
864                 return ide_stopped;
865         }
866         if (rq->cmd[13] & REQ_IDETAPE_READ) {
867                 pc = &tape->queued_pc;
868                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
869                 goto out;
870         }
871         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
872                 pc = &tape->queued_pc;
873                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
874                 goto out;
875         }
876         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
877                 pc = (struct ide_atapi_pc *) rq->buffer;
878                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
879                 rq->cmd[13] |= REQ_IDETAPE_PC2;
880                 goto out;
881         }
882         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
883                 idetape_media_access_finished(drive);
884                 return ide_stopped;
885         }
886         BUG();
887
888 out:
889         return idetape_issue_pc(drive, pc);
890 }
891
892 /*
893  * The function below uses __get_free_pages to allocate a data buffer of size
894  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
895  * much as possible.
896  *
897  * It returns a pointer to the newly allocated buffer, or NULL in case of
898  * failure.
899  */
900 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
901                                                   int full, int clear)
902 {
903         struct idetape_bh *prev_bh, *bh, *merge_bh;
904         int pages = tape->pages_per_buffer;
905         unsigned int order, b_allocd;
906         char *b_data = NULL;
907
908         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
909         bh = merge_bh;
910         if (bh == NULL)
911                 goto abort;
912
913         order = fls(pages) - 1;
914         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
915         if (!bh->b_data)
916                 goto abort;
917         b_allocd = (1 << order) * PAGE_SIZE;
918         pages &= (order-1);
919
920         if (clear)
921                 memset(bh->b_data, 0, b_allocd);
922         bh->b_reqnext = NULL;
923         bh->b_size = b_allocd;
924         atomic_set(&bh->b_count, full ? bh->b_size : 0);
925
926         while (pages) {
927                 order = fls(pages) - 1;
928                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
929                 if (!b_data)
930                         goto abort;
931                 b_allocd = (1 << order) * PAGE_SIZE;
932
933                 if (clear)
934                         memset(b_data, 0, b_allocd);
935
936                 /* newly allocated page frames below buffer header or ...*/
937                 if (bh->b_data == b_data + b_allocd) {
938                         bh->b_size += b_allocd;
939                         bh->b_data -= b_allocd;
940                         if (full)
941                                 atomic_add(b_allocd, &bh->b_count);
942                         continue;
943                 }
944                 /* they are above the header */
945                 if (b_data == bh->b_data + bh->b_size) {
946                         bh->b_size += b_allocd;
947                         if (full)
948                                 atomic_add(b_allocd, &bh->b_count);
949                         continue;
950                 }
951                 prev_bh = bh;
952                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
953                 if (!bh) {
954                         free_pages((unsigned long) b_data, order);
955                         goto abort;
956                 }
957                 bh->b_reqnext = NULL;
958                 bh->b_data = b_data;
959                 bh->b_size = b_allocd;
960                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
961                 prev_bh->b_reqnext = bh;
962
963                 pages &= (order-1);
964         }
965
966         bh->b_size -= tape->excess_bh_size;
967         if (full)
968                 atomic_sub(tape->excess_bh_size, &bh->b_count);
969         return merge_bh;
970 abort:
971         ide_tape_kfree_buffer(tape);
972         return NULL;
973 }
974
975 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
976                                         const char __user *buf, int n)
977 {
978         struct idetape_bh *bh = tape->bh;
979         int count;
980         int ret = 0;
981
982         while (n) {
983                 if (bh == NULL) {
984                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
985                                         __func__);
986                         return 1;
987                 }
988                 count = min((unsigned int)
989                                 (bh->b_size - atomic_read(&bh->b_count)),
990                                 (unsigned int)n);
991                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
992                                 count))
993                         ret = 1;
994                 n -= count;
995                 atomic_add(count, &bh->b_count);
996                 buf += count;
997                 if (atomic_read(&bh->b_count) == bh->b_size) {
998                         bh = bh->b_reqnext;
999                         if (bh)
1000                                 atomic_set(&bh->b_count, 0);
1001                 }
1002         }
1003         tape->bh = bh;
1004         return ret;
1005 }
1006
1007 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1008                                       int n)
1009 {
1010         struct idetape_bh *bh = tape->bh;
1011         int count;
1012         int ret = 0;
1013
1014         while (n) {
1015                 if (bh == NULL) {
1016                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1017                                         __func__);
1018                         return 1;
1019                 }
1020                 count = min(tape->b_count, n);
1021                 if  (copy_to_user(buf, tape->b_data, count))
1022                         ret = 1;
1023                 n -= count;
1024                 tape->b_data += count;
1025                 tape->b_count -= count;
1026                 buf += count;
1027                 if (!tape->b_count) {
1028                         bh = bh->b_reqnext;
1029                         tape->bh = bh;
1030                         if (bh) {
1031                                 tape->b_data = bh->b_data;
1032                                 tape->b_count = atomic_read(&bh->b_count);
1033                         }
1034                 }
1035         }
1036         return ret;
1037 }
1038
1039 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1040 {
1041         struct idetape_bh *bh = tape->merge_bh;
1042         tape->bh = tape->merge_bh;
1043
1044         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1045                 atomic_set(&bh->b_count, 0);
1046         else {
1047                 tape->b_data = bh->b_data;
1048                 tape->b_count = atomic_read(&bh->b_count);
1049         }
1050 }
1051
1052 /*
1053  * Write a filemark if write_filemark=1. Flush the device buffers without
1054  * writing a filemark otherwise.
1055  */
1056 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1057                 struct ide_atapi_pc *pc, int write_filemark)
1058 {
1059         ide_init_pc(pc);
1060         pc->c[0] = WRITE_FILEMARKS;
1061         pc->c[4] = write_filemark;
1062         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1063 }
1064
1065 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1066 {
1067         idetape_tape_t *tape = drive->driver_data;
1068         struct gendisk *disk = tape->disk;
1069         int load_attempted = 0;
1070
1071         /* Wait for the tape to become ready */
1072         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1073         timeout += jiffies;
1074         while (time_before(jiffies, timeout)) {
1075                 if (ide_do_test_unit_ready(drive, disk) == 0)
1076                         return 0;
1077                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1078                     || (tape->asc == 0x3A)) {
1079                         /* no media */
1080                         if (load_attempted)
1081                                 return -ENOMEDIUM;
1082                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1083                         load_attempted = 1;
1084                 /* not about to be ready */
1085                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1086                              (tape->ascq == 1 || tape->ascq == 8)))
1087                         return -EIO;
1088                 msleep(100);
1089         }
1090         return -EIO;
1091 }
1092
1093 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1094 {
1095         struct ide_tape_obj *tape = drive->driver_data;
1096         struct ide_atapi_pc pc;
1097         int rc;
1098
1099         idetape_create_write_filemark_cmd(drive, &pc, 0);
1100         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1101         if (rc)
1102                 return rc;
1103         idetape_wait_ready(drive, 60 * 5 * HZ);
1104         return 0;
1105 }
1106
1107 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1108 {
1109         ide_init_pc(pc);
1110         pc->c[0] = READ_POSITION;
1111         pc->req_xfer = 20;
1112 }
1113
1114 static int idetape_read_position(ide_drive_t *drive)
1115 {
1116         idetape_tape_t *tape = drive->driver_data;
1117         struct ide_atapi_pc pc;
1118         int position;
1119
1120         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1121
1122         idetape_create_read_position_cmd(&pc);
1123         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1124                 return -1;
1125         position = tape->first_frame;
1126         return position;
1127 }
1128
1129 static void idetape_create_locate_cmd(ide_drive_t *drive,
1130                 struct ide_atapi_pc *pc,
1131                 unsigned int block, u8 partition, int skip)
1132 {
1133         ide_init_pc(pc);
1134         pc->c[0] = POSITION_TO_ELEMENT;
1135         pc->c[1] = 2;
1136         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1137         pc->c[8] = partition;
1138         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1139 }
1140
1141 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1142 {
1143         idetape_tape_t *tape = drive->driver_data;
1144
1145         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1146                 return;
1147
1148         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1149         tape->merge_bh_size = 0;
1150         if (tape->merge_bh != NULL) {
1151                 ide_tape_kfree_buffer(tape);
1152                 tape->merge_bh = NULL;
1153         }
1154
1155         tape->chrdev_dir = IDETAPE_DIR_NONE;
1156 }
1157
1158 /*
1159  * Position the tape to the requested block using the LOCATE packet command.
1160  * A READ POSITION command is then issued to check where we are positioned. Like
1161  * all higher level operations, we queue the commands at the tail of the request
1162  * queue and wait for their completion.
1163  */
1164 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1165                 u8 partition, int skip)
1166 {
1167         idetape_tape_t *tape = drive->driver_data;
1168         struct gendisk *disk = tape->disk;
1169         int retval;
1170         struct ide_atapi_pc pc;
1171
1172         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1173                 __ide_tape_discard_merge_buffer(drive);
1174         idetape_wait_ready(drive, 60 * 5 * HZ);
1175         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1176         retval = ide_queue_pc_tail(drive, disk, &pc);
1177         if (retval)
1178                 return (retval);
1179
1180         idetape_create_read_position_cmd(&pc);
1181         return ide_queue_pc_tail(drive, disk, &pc);
1182 }
1183
1184 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1185                                           int restore_position)
1186 {
1187         idetape_tape_t *tape = drive->driver_data;
1188         int seek, position;
1189
1190         __ide_tape_discard_merge_buffer(drive);
1191         if (restore_position) {
1192                 position = idetape_read_position(drive);
1193                 seek = position > 0 ? position : 0;
1194                 if (idetape_position_tape(drive, seek, 0, 0)) {
1195                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1196                                          " %s\n", tape->name, __func__);
1197                         return;
1198                 }
1199         }
1200 }
1201
1202 /*
1203  * Generate a read/write request for the block device interface and wait for it
1204  * to be serviced.
1205  */
1206 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1207                                  struct idetape_bh *bh)
1208 {
1209         idetape_tape_t *tape = drive->driver_data;
1210         struct request *rq;
1211         int ret, errors;
1212
1213         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1214
1215         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1216         rq->cmd_type = REQ_TYPE_SPECIAL;
1217         rq->cmd[13] = cmd;
1218         rq->rq_disk = tape->disk;
1219         rq->special = (void *)bh;
1220         rq->sector = tape->first_frame;
1221         rq->nr_sectors = blocks;
1222         rq->current_nr_sectors = blocks;
1223         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1224
1225         errors = rq->errors;
1226         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1227         blk_put_request(rq);
1228
1229         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1230                 return 0;
1231
1232         if (tape->merge_bh)
1233                 idetape_init_merge_buffer(tape);
1234         if (errors == IDETAPE_ERROR_GENERAL)
1235                 return -EIO;
1236         return ret;
1237 }
1238
1239 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1240 {
1241         ide_init_pc(pc);
1242         pc->c[0] = INQUIRY;
1243         pc->c[4] = 254;
1244         pc->req_xfer = 254;
1245 }
1246
1247 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1248                 struct ide_atapi_pc *pc)
1249 {
1250         ide_init_pc(pc);
1251         pc->c[0] = REZERO_UNIT;
1252         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1253 }
1254
1255 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1256 {
1257         ide_init_pc(pc);
1258         pc->c[0] = ERASE;
1259         pc->c[1] = 1;
1260         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1261 }
1262
1263 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1264 {
1265         ide_init_pc(pc);
1266         pc->c[0] = SPACE;
1267         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1268         pc->c[1] = cmd;
1269         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1270 }
1271
1272 /* Queue up a character device originated write request. */
1273 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1274 {
1275         idetape_tape_t *tape = drive->driver_data;
1276
1277         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1278
1279         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1280                                      blocks, tape->merge_bh);
1281 }
1282
1283 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1284 {
1285         idetape_tape_t *tape = drive->driver_data;
1286         int blocks, min;
1287         struct idetape_bh *bh;
1288
1289         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1290                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1291                                 " but we are not writing.\n");
1292                 return;
1293         }
1294         if (tape->merge_bh_size > tape->buffer_size) {
1295                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1296                 tape->merge_bh_size = tape->buffer_size;
1297         }
1298         if (tape->merge_bh_size) {
1299                 blocks = tape->merge_bh_size / tape->blk_size;
1300                 if (tape->merge_bh_size % tape->blk_size) {
1301                         unsigned int i;
1302
1303                         blocks++;
1304                         i = tape->blk_size - tape->merge_bh_size %
1305                                 tape->blk_size;
1306                         bh = tape->bh->b_reqnext;
1307                         while (bh) {
1308                                 atomic_set(&bh->b_count, 0);
1309                                 bh = bh->b_reqnext;
1310                         }
1311                         bh = tape->bh;
1312                         while (i) {
1313                                 if (bh == NULL) {
1314                                         printk(KERN_INFO "ide-tape: bug,"
1315                                                          " bh NULL\n");
1316                                         break;
1317                                 }
1318                                 min = min(i, (unsigned int)(bh->b_size -
1319                                                 atomic_read(&bh->b_count)));
1320                                 memset(bh->b_data + atomic_read(&bh->b_count),
1321                                                 0, min);
1322                                 atomic_add(min, &bh->b_count);
1323                                 i -= min;
1324                                 bh = bh->b_reqnext;
1325                         }
1326                 }
1327                 (void) idetape_add_chrdev_write_request(drive, blocks);
1328                 tape->merge_bh_size = 0;
1329         }
1330         if (tape->merge_bh != NULL) {
1331                 ide_tape_kfree_buffer(tape);
1332                 tape->merge_bh = NULL;
1333         }
1334         tape->chrdev_dir = IDETAPE_DIR_NONE;
1335 }
1336
1337 static int idetape_init_read(ide_drive_t *drive)
1338 {
1339         idetape_tape_t *tape = drive->driver_data;
1340         int bytes_read;
1341
1342         /* Initialize read operation */
1343         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1344                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1345                         ide_tape_flush_merge_buffer(drive);
1346                         idetape_flush_tape_buffers(drive);
1347                 }
1348                 if (tape->merge_bh || tape->merge_bh_size) {
1349                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1350                                          " 0 now\n");
1351                         tape->merge_bh_size = 0;
1352                 }
1353                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1354                 if (!tape->merge_bh)
1355                         return -ENOMEM;
1356                 tape->chrdev_dir = IDETAPE_DIR_READ;
1357
1358                 /*
1359                  * Issue a read 0 command to ensure that DSC handshake is
1360                  * switched from completion mode to buffer available mode.
1361                  * No point in issuing this if DSC overlap isn't supported, some
1362                  * drives (Seagate STT3401A) will return an error.
1363                  */
1364                 if (drive->dsc_overlap) {
1365                         bytes_read = idetape_queue_rw_tail(drive,
1366                                                         REQ_IDETAPE_READ, 0,
1367                                                         tape->merge_bh);
1368                         if (bytes_read < 0) {
1369                                 ide_tape_kfree_buffer(tape);
1370                                 tape->merge_bh = NULL;
1371                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1372                                 return bytes_read;
1373                         }
1374                 }
1375         }
1376
1377         return 0;
1378 }
1379
1380 /* called from idetape_chrdev_read() to service a chrdev read request. */
1381 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1382 {
1383         idetape_tape_t *tape = drive->driver_data;
1384
1385         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1386
1387         /* If we are at a filemark, return a read length of 0 */
1388         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1389                 return 0;
1390
1391         idetape_init_read(drive);
1392
1393         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1394                                      tape->merge_bh);
1395 }
1396
1397 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1398 {
1399         idetape_tape_t *tape = drive->driver_data;
1400         struct idetape_bh *bh;
1401         int blocks;
1402
1403         while (bcount) {
1404                 unsigned int count;
1405
1406                 bh = tape->merge_bh;
1407                 count = min(tape->buffer_size, bcount);
1408                 bcount -= count;
1409                 blocks = count / tape->blk_size;
1410                 while (count) {
1411                         atomic_set(&bh->b_count,
1412                                    min(count, (unsigned int)bh->b_size));
1413                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1414                         count -= atomic_read(&bh->b_count);
1415                         bh = bh->b_reqnext;
1416                 }
1417                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1418                                       tape->merge_bh);
1419         }
1420 }
1421
1422 /*
1423  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1424  * currently support only one partition.
1425  */
1426 static int idetape_rewind_tape(ide_drive_t *drive)
1427 {
1428         struct ide_tape_obj *tape = drive->driver_data;
1429         struct gendisk *disk = tape->disk;
1430         int retval;
1431         struct ide_atapi_pc pc;
1432
1433         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1434
1435         idetape_create_rewind_cmd(drive, &pc);
1436         retval = ide_queue_pc_tail(drive, disk, &pc);
1437         if (retval)
1438                 return retval;
1439
1440         idetape_create_read_position_cmd(&pc);
1441         retval = ide_queue_pc_tail(drive, disk, &pc);
1442         if (retval)
1443                 return retval;
1444         return 0;
1445 }
1446
1447 /* mtio.h compatible commands should be issued to the chrdev interface. */
1448 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1449                                 unsigned long arg)
1450 {
1451         idetape_tape_t *tape = drive->driver_data;
1452         void __user *argp = (void __user *)arg;
1453
1454         struct idetape_config {
1455                 int dsc_rw_frequency;
1456                 int dsc_media_access_frequency;
1457                 int nr_stages;
1458         } config;
1459
1460         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1461
1462         switch (cmd) {
1463         case 0x0340:
1464                 if (copy_from_user(&config, argp, sizeof(config)))
1465                         return -EFAULT;
1466                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1467                 break;
1468         case 0x0350:
1469                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1470                 config.nr_stages = 1;
1471                 if (copy_to_user(argp, &config, sizeof(config)))
1472                         return -EFAULT;
1473                 break;
1474         default:
1475                 return -EIO;
1476         }
1477         return 0;
1478 }
1479
1480 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1481                                         int mt_count)
1482 {
1483         idetape_tape_t *tape = drive->driver_data;
1484         struct gendisk *disk = tape->disk;
1485         struct ide_atapi_pc pc;
1486         int retval, count = 0;
1487         int sprev = !!(tape->caps[4] & 0x20);
1488
1489         if (mt_count == 0)
1490                 return 0;
1491         if (MTBSF == mt_op || MTBSFM == mt_op) {
1492                 if (!sprev)
1493                         return -EIO;
1494                 mt_count = -mt_count;
1495         }
1496
1497         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1498                 tape->merge_bh_size = 0;
1499                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1500                         ++count;
1501                 ide_tape_discard_merge_buffer(drive, 0);
1502         }
1503
1504         switch (mt_op) {
1505         case MTFSF:
1506         case MTBSF:
1507                 idetape_create_space_cmd(&pc, mt_count - count,
1508                                          IDETAPE_SPACE_OVER_FILEMARK);
1509                 return ide_queue_pc_tail(drive, disk, &pc);
1510         case MTFSFM:
1511         case MTBSFM:
1512                 if (!sprev)
1513                         return -EIO;
1514                 retval = idetape_space_over_filemarks(drive, MTFSF,
1515                                                       mt_count - count);
1516                 if (retval)
1517                         return retval;
1518                 count = (MTBSFM == mt_op ? 1 : -1);
1519                 return idetape_space_over_filemarks(drive, MTFSF, count);
1520         default:
1521                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1522                                 mt_op);
1523                 return -EIO;
1524         }
1525 }
1526
1527 /*
1528  * Our character device read / write functions.
1529  *
1530  * The tape is optimized to maximize throughput when it is transferring an
1531  * integral number of the "continuous transfer limit", which is a parameter of
1532  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1533  *
1534  * As of version 1.3 of the driver, the character device provides an abstract
1535  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1536  * same backup/restore procedure is supported. The driver will internally
1537  * convert the requests to the recommended transfer unit, so that an unmatch
1538  * between the user's block size to the recommended size will only result in a
1539  * (slightly) increased driver overhead, but will no longer hit performance.
1540  * This is not applicable to Onstream.
1541  */
1542 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1543                                    size_t count, loff_t *ppos)
1544 {
1545         struct ide_tape_obj *tape = ide_tape_f(file);
1546         ide_drive_t *drive = tape->drive;
1547         ssize_t bytes_read, temp, actually_read = 0, rc;
1548         ssize_t ret = 0;
1549         u16 ctl = *(u16 *)&tape->caps[12];
1550
1551         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1552
1553         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1554                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1555                         if (count > tape->blk_size &&
1556                             (count % tape->blk_size) == 0)
1557                                 tape->user_bs_factor = count / tape->blk_size;
1558         }
1559         rc = idetape_init_read(drive);
1560         if (rc < 0)
1561                 return rc;
1562         if (count == 0)
1563                 return (0);
1564         if (tape->merge_bh_size) {
1565                 actually_read = min((unsigned int)(tape->merge_bh_size),
1566                                     (unsigned int)count);
1567                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1568                         ret = -EFAULT;
1569                 buf += actually_read;
1570                 tape->merge_bh_size -= actually_read;
1571                 count -= actually_read;
1572         }
1573         while (count >= tape->buffer_size) {
1574                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1575                 if (bytes_read <= 0)
1576                         goto finish;
1577                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1578                         ret = -EFAULT;
1579                 buf += bytes_read;
1580                 count -= bytes_read;
1581                 actually_read += bytes_read;
1582         }
1583         if (count) {
1584                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1585                 if (bytes_read <= 0)
1586                         goto finish;
1587                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1588                 if (idetape_copy_stage_to_user(tape, buf, temp))
1589                         ret = -EFAULT;
1590                 actually_read += temp;
1591                 tape->merge_bh_size = bytes_read-temp;
1592         }
1593 finish:
1594         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1595                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1596
1597                 idetape_space_over_filemarks(drive, MTFSF, 1);
1598                 return 0;
1599         }
1600
1601         return ret ? ret : actually_read;
1602 }
1603
1604 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1605                                      size_t count, loff_t *ppos)
1606 {
1607         struct ide_tape_obj *tape = ide_tape_f(file);
1608         ide_drive_t *drive = tape->drive;
1609         ssize_t actually_written = 0;
1610         ssize_t ret = 0;
1611         u16 ctl = *(u16 *)&tape->caps[12];
1612
1613         /* The drive is write protected. */
1614         if (tape->write_prot)
1615                 return -EACCES;
1616
1617         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1618
1619         /* Initialize write operation */
1620         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1621                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1622                         ide_tape_discard_merge_buffer(drive, 1);
1623                 if (tape->merge_bh || tape->merge_bh_size) {
1624                         printk(KERN_ERR "ide-tape: merge_bh_size "
1625                                 "should be 0 now\n");
1626                         tape->merge_bh_size = 0;
1627                 }
1628                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1629                 if (!tape->merge_bh)
1630                         return -ENOMEM;
1631                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1632                 idetape_init_merge_buffer(tape);
1633
1634                 /*
1635                  * Issue a write 0 command to ensure that DSC handshake is
1636                  * switched from completion mode to buffer available mode. No
1637                  * point in issuing this if DSC overlap isn't supported, some
1638                  * drives (Seagate STT3401A) will return an error.
1639                  */
1640                 if (drive->dsc_overlap) {
1641                         ssize_t retval = idetape_queue_rw_tail(drive,
1642                                                         REQ_IDETAPE_WRITE, 0,
1643                                                         tape->merge_bh);
1644                         if (retval < 0) {
1645                                 ide_tape_kfree_buffer(tape);
1646                                 tape->merge_bh = NULL;
1647                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1648                                 return retval;
1649                         }
1650                 }
1651         }
1652         if (count == 0)
1653                 return (0);
1654         if (tape->merge_bh_size) {
1655                 if (tape->merge_bh_size >= tape->buffer_size) {
1656                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1657                         tape->merge_bh_size = 0;
1658                 }
1659                 actually_written = min((unsigned int)
1660                                 (tape->buffer_size - tape->merge_bh_size),
1661                                 (unsigned int)count);
1662                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1663                                 ret = -EFAULT;
1664                 buf += actually_written;
1665                 tape->merge_bh_size += actually_written;
1666                 count -= actually_written;
1667
1668                 if (tape->merge_bh_size == tape->buffer_size) {
1669                         ssize_t retval;
1670                         tape->merge_bh_size = 0;
1671                         retval = idetape_add_chrdev_write_request(drive, ctl);
1672                         if (retval <= 0)
1673                                 return (retval);
1674                 }
1675         }
1676         while (count >= tape->buffer_size) {
1677                 ssize_t retval;
1678                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1679                         ret = -EFAULT;
1680                 buf += tape->buffer_size;
1681                 count -= tape->buffer_size;
1682                 retval = idetape_add_chrdev_write_request(drive, ctl);
1683                 actually_written += tape->buffer_size;
1684                 if (retval <= 0)
1685                         return (retval);
1686         }
1687         if (count) {
1688                 actually_written += count;
1689                 if (idetape_copy_stage_from_user(tape, buf, count))
1690                         ret = -EFAULT;
1691                 tape->merge_bh_size += count;
1692         }
1693         return ret ? ret : actually_written;
1694 }
1695
1696 static int idetape_write_filemark(ide_drive_t *drive)
1697 {
1698         struct ide_tape_obj *tape = drive->driver_data;
1699         struct ide_atapi_pc pc;
1700
1701         /* Write a filemark */
1702         idetape_create_write_filemark_cmd(drive, &pc, 1);
1703         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1704                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1705                 return -EIO;
1706         }
1707         return 0;
1708 }
1709
1710 /*
1711  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1712  * requested.
1713  *
1714  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1715  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1716  * usually not supported.
1717  *
1718  * The following commands are currently not supported:
1719  *
1720  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1721  * MT_ST_WRITE_THRESHOLD.
1722  */
1723 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1724 {
1725         idetape_tape_t *tape = drive->driver_data;
1726         struct gendisk *disk = tape->disk;
1727         struct ide_atapi_pc pc;
1728         int i, retval;
1729
1730         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1731                         mt_op, mt_count);
1732
1733         switch (mt_op) {
1734         case MTFSF:
1735         case MTFSFM:
1736         case MTBSF:
1737         case MTBSFM:
1738                 if (!mt_count)
1739                         return 0;
1740                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1741         default:
1742                 break;
1743         }
1744
1745         switch (mt_op) {
1746         case MTWEOF:
1747                 if (tape->write_prot)
1748                         return -EACCES;
1749                 ide_tape_discard_merge_buffer(drive, 1);
1750                 for (i = 0; i < mt_count; i++) {
1751                         retval = idetape_write_filemark(drive);
1752                         if (retval)
1753                                 return retval;
1754                 }
1755                 return 0;
1756         case MTREW:
1757                 ide_tape_discard_merge_buffer(drive, 0);
1758                 if (idetape_rewind_tape(drive))
1759                         return -EIO;
1760                 return 0;
1761         case MTLOAD:
1762                 ide_tape_discard_merge_buffer(drive, 0);
1763                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1764         case MTUNLOAD:
1765         case MTOFFL:
1766                 /*
1767                  * If door is locked, attempt to unlock before
1768                  * attempting to eject.
1769                  */
1770                 if (tape->door_locked) {
1771                         if (!ide_set_media_lock(drive, disk, 0))
1772                                 tape->door_locked = DOOR_UNLOCKED;
1773                 }
1774                 ide_tape_discard_merge_buffer(drive, 0);
1775                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1776                 if (!retval)
1777                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1778                 return retval;
1779         case MTNOP:
1780                 ide_tape_discard_merge_buffer(drive, 0);
1781                 return idetape_flush_tape_buffers(drive);
1782         case MTRETEN:
1783                 ide_tape_discard_merge_buffer(drive, 0);
1784                 return ide_do_start_stop(drive, disk,
1785                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1786         case MTEOM:
1787                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1788                 return ide_queue_pc_tail(drive, disk, &pc);
1789         case MTERASE:
1790                 (void)idetape_rewind_tape(drive);
1791                 idetape_create_erase_cmd(&pc);
1792                 return ide_queue_pc_tail(drive, disk, &pc);
1793         case MTSETBLK:
1794                 if (mt_count) {
1795                         if (mt_count < tape->blk_size ||
1796                             mt_count % tape->blk_size)
1797                                 return -EIO;
1798                         tape->user_bs_factor = mt_count / tape->blk_size;
1799                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1800                 } else
1801                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1802                 return 0;
1803         case MTSEEK:
1804                 ide_tape_discard_merge_buffer(drive, 0);
1805                 return idetape_position_tape(drive,
1806                         mt_count * tape->user_bs_factor, tape->partition, 0);
1807         case MTSETPART:
1808                 ide_tape_discard_merge_buffer(drive, 0);
1809                 return idetape_position_tape(drive, 0, mt_count, 0);
1810         case MTFSR:
1811         case MTBSR:
1812         case MTLOCK:
1813                 retval = ide_set_media_lock(drive, disk, 1);
1814                 if (retval)
1815                         return retval;
1816                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1817                 return 0;
1818         case MTUNLOCK:
1819                 retval = ide_set_media_lock(drive, disk, 0);
1820                 if (retval)
1821                         return retval;
1822                 tape->door_locked = DOOR_UNLOCKED;
1823                 return 0;
1824         default:
1825                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1826                                 mt_op);
1827                 return -EIO;
1828         }
1829 }
1830
1831 /*
1832  * Our character device ioctls. General mtio.h magnetic io commands are
1833  * supported here, and not in the corresponding block interface. Our own
1834  * ide-tape ioctls are supported on both interfaces.
1835  */
1836 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1837                                 unsigned int cmd, unsigned long arg)
1838 {
1839         struct ide_tape_obj *tape = ide_tape_f(file);
1840         ide_drive_t *drive = tape->drive;
1841         struct mtop mtop;
1842         struct mtget mtget;
1843         struct mtpos mtpos;
1844         int block_offset = 0, position = tape->first_frame;
1845         void __user *argp = (void __user *)arg;
1846
1847         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1848
1849         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1850                 ide_tape_flush_merge_buffer(drive);
1851                 idetape_flush_tape_buffers(drive);
1852         }
1853         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1854                 block_offset = tape->merge_bh_size /
1855                         (tape->blk_size * tape->user_bs_factor);
1856                 position = idetape_read_position(drive);
1857                 if (position < 0)
1858                         return -EIO;
1859         }
1860         switch (cmd) {
1861         case MTIOCTOP:
1862                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1863                         return -EFAULT;
1864                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1865         case MTIOCGET:
1866                 memset(&mtget, 0, sizeof(struct mtget));
1867                 mtget.mt_type = MT_ISSCSI2;
1868                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1869                 mtget.mt_dsreg =
1870                         ((tape->blk_size * tape->user_bs_factor)
1871                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1872
1873                 if (tape->drv_write_prot)
1874                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1875
1876                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1877                         return -EFAULT;
1878                 return 0;
1879         case MTIOCPOS:
1880                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1881                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1882                         return -EFAULT;
1883                 return 0;
1884         default:
1885                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1886                         ide_tape_discard_merge_buffer(drive, 1);
1887                 return idetape_blkdev_ioctl(drive, cmd, arg);
1888         }
1889 }
1890
1891 /*
1892  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1893  * block size with the reported value.
1894  */
1895 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1896 {
1897         idetape_tape_t *tape = drive->driver_data;
1898         struct ide_atapi_pc pc;
1899
1900         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1901         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1902                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1903                 if (tape->blk_size == 0) {
1904                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1905                                             "block size, assuming 32k\n");
1906                         tape->blk_size = 32768;
1907                 }
1908                 return;
1909         }
1910         tape->blk_size = (pc.buf[4 + 5] << 16) +
1911                                 (pc.buf[4 + 6] << 8)  +
1912                                  pc.buf[4 + 7];
1913         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1914 }
1915
1916 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1917 {
1918         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1919         ide_drive_t *drive;
1920         idetape_tape_t *tape;
1921         int retval;
1922
1923         if (i >= MAX_HWIFS * MAX_DRIVES)
1924                 return -ENXIO;
1925
1926         lock_kernel();
1927         tape = ide_tape_chrdev_get(i);
1928         if (!tape) {
1929                 unlock_kernel();
1930                 return -ENXIO;
1931         }
1932
1933         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1934
1935         /*
1936          * We really want to do nonseekable_open(inode, filp); here, but some
1937          * versions of tar incorrectly call lseek on tapes and bail out if that
1938          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1939          */
1940         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1941
1942         drive = tape->drive;
1943
1944         filp->private_data = tape;
1945
1946         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1947                 retval = -EBUSY;
1948                 goto out_put_tape;
1949         }
1950
1951         retval = idetape_wait_ready(drive, 60 * HZ);
1952         if (retval) {
1953                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1954                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1955                 goto out_put_tape;
1956         }
1957
1958         idetape_read_position(drive);
1959         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1960                 (void)idetape_rewind_tape(drive);
1961
1962         /* Read block size and write protect status from drive. */
1963         ide_tape_get_bsize_from_bdesc(drive);
1964
1965         /* Set write protect flag if device is opened as read-only. */
1966         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1967                 tape->write_prot = 1;
1968         else
1969                 tape->write_prot = tape->drv_write_prot;
1970
1971         /* Make sure drive isn't write protected if user wants to write. */
1972         if (tape->write_prot) {
1973                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1974                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1975                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1976                         retval = -EROFS;
1977                         goto out_put_tape;
1978                 }
1979         }
1980
1981         /* Lock the tape drive door so user can't eject. */
1982         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1983                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1984                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1985                                 tape->door_locked = DOOR_LOCKED;
1986                 }
1987         }
1988         unlock_kernel();
1989         return 0;
1990
1991 out_put_tape:
1992         ide_tape_put(tape);
1993         unlock_kernel();
1994         return retval;
1995 }
1996
1997 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
1998 {
1999         idetape_tape_t *tape = drive->driver_data;
2000
2001         ide_tape_flush_merge_buffer(drive);
2002         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2003         if (tape->merge_bh != NULL) {
2004                 idetape_pad_zeros(drive, tape->blk_size *
2005                                 (tape->user_bs_factor - 1));
2006                 ide_tape_kfree_buffer(tape);
2007                 tape->merge_bh = NULL;
2008         }
2009         idetape_write_filemark(drive);
2010         idetape_flush_tape_buffers(drive);
2011         idetape_flush_tape_buffers(drive);
2012 }
2013
2014 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2015 {
2016         struct ide_tape_obj *tape = ide_tape_f(filp);
2017         ide_drive_t *drive = tape->drive;
2018         unsigned int minor = iminor(inode);
2019
2020         lock_kernel();
2021         tape = drive->driver_data;
2022
2023         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2024
2025         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2026                 idetape_write_release(drive, minor);
2027         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2028                 if (minor < 128)
2029                         ide_tape_discard_merge_buffer(drive, 1);
2030         }
2031
2032         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2033                 (void) idetape_rewind_tape(drive);
2034         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2035                 if (tape->door_locked == DOOR_LOCKED) {
2036                         if (!ide_set_media_lock(drive, tape->disk, 0))
2037                                 tape->door_locked = DOOR_UNLOCKED;
2038                 }
2039         }
2040         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2041         ide_tape_put(tape);
2042         unlock_kernel();
2043         return 0;
2044 }
2045
2046 static void idetape_get_inquiry_results(ide_drive_t *drive)
2047 {
2048         idetape_tape_t *tape = drive->driver_data;
2049         struct ide_atapi_pc pc;
2050         char fw_rev[4], vendor_id[8], product_id[16];
2051
2052         idetape_create_inquiry_cmd(&pc);
2053         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2054                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2055                                 tape->name);
2056                 return;
2057         }
2058         memcpy(vendor_id, &pc.buf[8], 8);
2059         memcpy(product_id, &pc.buf[16], 16);
2060         memcpy(fw_rev, &pc.buf[32], 4);
2061
2062         ide_fixstring(vendor_id, 8, 0);
2063         ide_fixstring(product_id, 16, 0);
2064         ide_fixstring(fw_rev, 4, 0);
2065
2066         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2067                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2068 }
2069
2070 /*
2071  * Ask the tape about its various parameters. In particular, we will adjust our
2072  * data transfer buffer size to the recommended value as returned by the tape.
2073  */
2074 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2075 {
2076         idetape_tape_t *tape = drive->driver_data;
2077         struct ide_atapi_pc pc;
2078         u8 *caps;
2079         u8 speed, max_speed;
2080
2081         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2082         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2083                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2084                                 " some default values\n");
2085                 tape->blk_size = 512;
2086                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2087                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2088                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2089                 return;
2090         }
2091         caps = pc.buf + 4 + pc.buf[3];
2092
2093         /* convert to host order and save for later use */
2094         speed = be16_to_cpup((__be16 *)&caps[14]);
2095         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2096
2097         *(u16 *)&caps[8] = max_speed;
2098         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2099         *(u16 *)&caps[14] = speed;
2100         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2101
2102         if (!speed) {
2103                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2104                                 "(assuming 650KB/sec)\n", drive->name);
2105                 *(u16 *)&caps[14] = 650;
2106         }
2107         if (!max_speed) {
2108                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2109                                 "(assuming 650KB/sec)\n", drive->name);
2110                 *(u16 *)&caps[8] = 650;
2111         }
2112
2113         memcpy(&tape->caps, caps, 20);
2114
2115         /* device lacks locking support according to capabilities page */
2116         if ((caps[6] & 1) == 0)
2117                 drive->atapi_flags |= IDE_AFLAG_NO_DOORLOCK;
2118
2119         if (caps[7] & 0x02)
2120                 tape->blk_size = 512;
2121         else if (caps[7] & 0x04)
2122                 tape->blk_size = 1024;
2123 }
2124
2125 #ifdef CONFIG_IDE_PROC_FS
2126 #define ide_tape_devset_get(name, field) \
2127 static int get_##name(ide_drive_t *drive) \
2128 { \
2129         idetape_tape_t *tape = drive->driver_data; \
2130         return tape->field; \
2131 }
2132
2133 #define ide_tape_devset_set(name, field) \
2134 static int set_##name(ide_drive_t *drive, int arg) \
2135 { \
2136         idetape_tape_t *tape = drive->driver_data; \
2137         tape->field = arg; \
2138         return 0; \
2139 }
2140
2141 #define ide_tape_devset_rw_field(_name, _field) \
2142 ide_tape_devset_get(_name, _field) \
2143 ide_tape_devset_set(_name, _field) \
2144 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2145
2146 #define ide_tape_devset_r_field(_name, _field) \
2147 ide_tape_devset_get(_name, _field) \
2148 IDE_DEVSET(_name, 0, get_##_name, NULL)
2149
2150 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2151 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2152 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2153 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2154
2155 ide_devset_rw_field(dsc_overlap, dsc_overlap);
2156
2157 ide_tape_devset_rw_field(debug_mask, debug_mask);
2158 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2159
2160 ide_tape_devset_r_field(avg_speed, avg_speed);
2161 ide_tape_devset_r_field(speed, caps[14]);
2162 ide_tape_devset_r_field(buffer, caps[16]);
2163 ide_tape_devset_r_field(buffer_size, buffer_size);
2164
2165 static const struct ide_proc_devset idetape_settings[] = {
2166         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2167         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2168         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2169         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2170         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2171         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2172         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2173                                         mulf_tdsc, divf_tdsc),
2174         { 0 },
2175 };
2176 #endif
2177
2178 /*
2179  * The function below is called to:
2180  *
2181  * 1. Initialize our various state variables.
2182  * 2. Ask the tape for its capabilities.
2183  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2184  * is chosen based on the recommendation which we received in step 2.
2185  *
2186  * Note that at this point ide.c already assigned us an irq, so that we can
2187  * queue requests here and wait for their completion.
2188  */
2189 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2190 {
2191         unsigned long t;
2192         int speed;
2193         int buffer_size;
2194         u8 gcw[2];
2195         u16 *ctl = (u16 *)&tape->caps[12];
2196
2197         drive->pc_callback       = ide_tape_callback;
2198         drive->pc_update_buffers = idetape_update_buffers;
2199         drive->pc_io_buffers     = ide_tape_io_buffers;
2200
2201         spin_lock_init(&tape->lock);
2202         drive->dsc_overlap = 1;
2203         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2204                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2205                                  tape->name);
2206                 drive->dsc_overlap = 0;
2207         }
2208         /* Seagate Travan drives do not support DSC overlap. */
2209         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2210                 drive->dsc_overlap = 0;
2211         tape->minor = minor;
2212         tape->name[0] = 'h';
2213         tape->name[1] = 't';
2214         tape->name[2] = '0' + minor;
2215         tape->chrdev_dir = IDETAPE_DIR_NONE;
2216
2217         *((u16 *)&gcw) = drive->id[ATA_ID_CONFIG];
2218
2219         /* Command packet DRQ type */
2220         if (((gcw[0] & 0x60) >> 5) == 1)
2221                 set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
2222
2223         idetape_get_inquiry_results(drive);
2224         idetape_get_mode_sense_results(drive);
2225         ide_tape_get_bsize_from_bdesc(drive);
2226         tape->user_bs_factor = 1;
2227         tape->buffer_size = *ctl * tape->blk_size;
2228         while (tape->buffer_size > 0xffff) {
2229                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2230                 *ctl /= 2;
2231                 tape->buffer_size = *ctl * tape->blk_size;
2232         }
2233         buffer_size = tape->buffer_size;
2234         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2235         if (buffer_size % PAGE_SIZE) {
2236                 tape->pages_per_buffer++;
2237                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2238         }
2239
2240         /* select the "best" DSC read/write polling freq */
2241         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2242
2243         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2244
2245         /*
2246          * Ensure that the number we got makes sense; limit it within
2247          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2248          */
2249         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2250                                          IDETAPE_DSC_RW_MAX);
2251         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2252                 "%lums tDSC%s\n",
2253                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2254                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2255                 tape->buffer_size / 1024,
2256                 tape->best_dsc_rw_freq * 1000 / HZ,
2257                 drive->using_dma ? ", DMA":"");
2258
2259         ide_proc_register_driver(drive, tape->driver);
2260 }
2261
2262 static void ide_tape_remove(ide_drive_t *drive)
2263 {
2264         idetape_tape_t *tape = drive->driver_data;
2265
2266         ide_proc_unregister_driver(drive, tape->driver);
2267
2268         ide_unregister_region(tape->disk);
2269
2270         ide_tape_put(tape);
2271 }
2272
2273 static void ide_tape_release(struct kref *kref)
2274 {
2275         struct ide_tape_obj *tape = to_ide_tape(kref);
2276         ide_drive_t *drive = tape->drive;
2277         struct gendisk *g = tape->disk;
2278
2279         BUG_ON(tape->merge_bh_size);
2280
2281         drive->dsc_overlap = 0;
2282         drive->driver_data = NULL;
2283         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2284         device_destroy(idetape_sysfs_class,
2285                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2286         idetape_devs[tape->minor] = NULL;
2287         g->private_data = NULL;
2288         put_disk(g);
2289         kfree(tape);
2290 }
2291
2292 #ifdef CONFIG_IDE_PROC_FS
2293 static int proc_idetape_read_name
2294         (char *page, char **start, off_t off, int count, int *eof, void *data)
2295 {
2296         ide_drive_t     *drive = (ide_drive_t *) data;
2297         idetape_tape_t  *tape = drive->driver_data;
2298         char            *out = page;
2299         int             len;
2300
2301         len = sprintf(out, "%s\n", tape->name);
2302         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2303 }
2304
2305 static ide_proc_entry_t idetape_proc[] = {
2306         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2307         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2308         { NULL, 0, NULL, NULL }
2309 };
2310 #endif
2311
2312 static int ide_tape_probe(ide_drive_t *);
2313
2314 static ide_driver_t idetape_driver = {
2315         .gen_driver = {
2316                 .owner          = THIS_MODULE,
2317                 .name           = "ide-tape",
2318                 .bus            = &ide_bus_type,
2319         },
2320         .probe                  = ide_tape_probe,
2321         .remove                 = ide_tape_remove,
2322         .version                = IDETAPE_VERSION,
2323         .media                  = ide_tape,
2324         .do_request             = idetape_do_request,
2325         .end_request            = idetape_end_request,
2326         .error                  = __ide_error,
2327 #ifdef CONFIG_IDE_PROC_FS
2328         .proc                   = idetape_proc,
2329         .settings               = idetape_settings,
2330 #endif
2331 };
2332
2333 /* Our character device supporting functions, passed to register_chrdev. */
2334 static const struct file_operations idetape_fops = {
2335         .owner          = THIS_MODULE,
2336         .read           = idetape_chrdev_read,
2337         .write          = idetape_chrdev_write,
2338         .ioctl          = idetape_chrdev_ioctl,
2339         .open           = idetape_chrdev_open,
2340         .release        = idetape_chrdev_release,
2341 };
2342
2343 static int idetape_open(struct inode *inode, struct file *filp)
2344 {
2345         struct gendisk *disk = inode->i_bdev->bd_disk;
2346         struct ide_tape_obj *tape;
2347
2348         tape = ide_tape_get(disk);
2349         if (!tape)
2350                 return -ENXIO;
2351
2352         return 0;
2353 }
2354
2355 static int idetape_release(struct inode *inode, struct file *filp)
2356 {
2357         struct gendisk *disk = inode->i_bdev->bd_disk;
2358         struct ide_tape_obj *tape = ide_tape_g(disk);
2359
2360         ide_tape_put(tape);
2361
2362         return 0;
2363 }
2364
2365 static int idetape_ioctl(struct inode *inode, struct file *file,
2366                         unsigned int cmd, unsigned long arg)
2367 {
2368         struct block_device *bdev = inode->i_bdev;
2369         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2370         ide_drive_t *drive = tape->drive;
2371         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2372         if (err == -EINVAL)
2373                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2374         return err;
2375 }
2376
2377 static struct block_device_operations idetape_block_ops = {
2378         .owner          = THIS_MODULE,
2379         .open           = idetape_open,
2380         .release        = idetape_release,
2381         .ioctl          = idetape_ioctl,
2382 };
2383
2384 static int ide_tape_probe(ide_drive_t *drive)
2385 {
2386         idetape_tape_t *tape;
2387         struct gendisk *g;
2388         int minor;
2389
2390         if (!strstr("ide-tape", drive->driver_req))
2391                 goto failed;
2392
2393         if (drive->media != ide_tape)
2394                 goto failed;
2395
2396         if (drive->id_read == 1 && !ide_check_atapi_device(drive, DRV_NAME)) {
2397                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2398                                 " the driver\n", drive->name);
2399                 goto failed;
2400         }
2401         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2402         if (tape == NULL) {
2403                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2404                                 drive->name);
2405                 goto failed;
2406         }
2407
2408         g = alloc_disk(1 << PARTN_BITS);
2409         if (!g)
2410                 goto out_free_tape;
2411
2412         ide_init_disk(g, drive);
2413
2414         kref_init(&tape->kref);
2415
2416         tape->drive = drive;
2417         tape->driver = &idetape_driver;
2418         tape->disk = g;
2419
2420         g->private_data = &tape->driver;
2421
2422         drive->driver_data = tape;
2423
2424         mutex_lock(&idetape_ref_mutex);
2425         for (minor = 0; idetape_devs[minor]; minor++)
2426                 ;
2427         idetape_devs[minor] = tape;
2428         mutex_unlock(&idetape_ref_mutex);
2429
2430         idetape_setup(drive, tape, minor);
2431
2432         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2433                               MKDEV(IDETAPE_MAJOR, minor), NULL,
2434                               "%s", tape->name);
2435         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2436                               MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2437                               "n%s", tape->name);
2438
2439         g->fops = &idetape_block_ops;
2440         ide_register_region(g);
2441
2442         return 0;
2443
2444 out_free_tape:
2445         kfree(tape);
2446 failed:
2447         return -ENODEV;
2448 }
2449
2450 static void __exit idetape_exit(void)
2451 {
2452         driver_unregister(&idetape_driver.gen_driver);
2453         class_destroy(idetape_sysfs_class);
2454         unregister_chrdev(IDETAPE_MAJOR, "ht");
2455 }
2456
2457 static int __init idetape_init(void)
2458 {
2459         int error = 1;
2460         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2461         if (IS_ERR(idetape_sysfs_class)) {
2462                 idetape_sysfs_class = NULL;
2463                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2464                 error = -EBUSY;
2465                 goto out;
2466         }
2467
2468         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2469                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2470                                 " interface\n");
2471                 error = -EBUSY;
2472                 goto out_free_class;
2473         }
2474
2475         error = driver_register(&idetape_driver.gen_driver);
2476         if (error)
2477                 goto out_free_driver;
2478
2479         return 0;
2480
2481 out_free_driver:
2482         driver_unregister(&idetape_driver.gen_driver);
2483 out_free_class:
2484         class_destroy(idetape_sysfs_class);
2485 out:
2486         return error;
2487 }
2488
2489 MODULE_ALIAS("ide:*m-tape*");
2490 module_init(idetape_init);
2491 module_exit(idetape_exit);
2492 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2493 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2494 MODULE_LICENSE("GPL");