ide: make ide_pc_intr() static
[linux-2.6.git] / drivers / ide / ide-tape.c
1 /*
2  * IDE ATAPI streaming tape driver.
3  *
4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
6  *
7  * This driver was constructed as a student project in the software laboratory
8  * of the faculty of electrical engineering in the Technion - Israel's
9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
10  *
11  * It is hereby placed under the terms of the GNU general public license.
12  * (See linux/COPYING).
13  *
14  * For a historical changelog see
15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
16  */
17
18 #define 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 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
658 {
659         return ide_transfer_pc(drive, WAIT_TAPE_CMD, NULL);
660 }
661
662 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
663                 struct ide_atapi_pc *pc)
664 {
665         idetape_tape_t *tape = drive->driver_data;
666
667         if (drive->pc->c[0] == REQUEST_SENSE &&
668             pc->c[0] == REQUEST_SENSE) {
669                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
670                         "Two request sense in serial were issued\n");
671         }
672
673         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
674                 tape->failed_pc = pc;
675
676         /* Set the current packet command */
677         drive->pc = pc;
678
679         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
680                 (pc->flags & PC_FLAG_ABORT)) {
681                 /*
682                  * We will "abort" retrying a packet command in case legitimate
683                  * error code was received (crossing a filemark, or end of the
684                  * media, for example).
685                  */
686                 if (!(pc->flags & PC_FLAG_ABORT)) {
687                         if (!(pc->c[0] == TEST_UNIT_READY &&
688                               tape->sense_key == 2 && tape->asc == 4 &&
689                              (tape->ascq == 1 || tape->ascq == 8))) {
690                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
691                                                 "pc = %2x, key = %2x, "
692                                                 "asc = %2x, ascq = %2x\n",
693                                                 tape->name, pc->c[0],
694                                                 tape->sense_key, tape->asc,
695                                                 tape->ascq);
696                         }
697                         /* Giving up */
698                         pc->error = IDETAPE_ERROR_GENERAL;
699                 }
700                 tape->failed_pc = NULL;
701                 drive->pc_callback(drive, 0);
702                 return ide_stopped;
703         }
704         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
705
706         pc->retries++;
707
708         return ide_issue_pc(drive, idetape_transfer_pc, WAIT_TAPE_CMD, NULL);
709 }
710
711 /* A mode sense command is used to "sense" tape parameters. */
712 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
713 {
714         ide_init_pc(pc);
715         pc->c[0] = MODE_SENSE;
716         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
717                 /* DBD = 1 - Don't return block descriptors */
718                 pc->c[1] = 8;
719         pc->c[2] = page_code;
720         /*
721          * Changed pc->c[3] to 0 (255 will at best return unused info).
722          *
723          * For SCSI this byte is defined as subpage instead of high byte
724          * of length and some IDE drives seem to interpret it this way
725          * and return an error when 255 is used.
726          */
727         pc->c[3] = 0;
728         /* We will just discard data in that case */
729         pc->c[4] = 255;
730         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
731                 pc->req_xfer = 12;
732         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
733                 pc->req_xfer = 24;
734         else
735                 pc->req_xfer = 50;
736 }
737
738 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
739 {
740         ide_hwif_t *hwif = drive->hwif;
741         idetape_tape_t *tape = drive->driver_data;
742         struct ide_atapi_pc *pc = drive->pc;
743         u8 stat;
744
745         stat = hwif->tp_ops->read_status(hwif);
746
747         if (stat & ATA_DSC) {
748                 if (stat & ATA_ERR) {
749                         /* Error detected */
750                         if (pc->c[0] != TEST_UNIT_READY)
751                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
752                                                 tape->name);
753                         /* Retry operation */
754                         ide_retry_pc(drive, tape->disk);
755                         return ide_stopped;
756                 }
757                 pc->error = 0;
758         } else {
759                 pc->error = IDETAPE_ERROR_GENERAL;
760                 tape->failed_pc = NULL;
761         }
762         drive->pc_callback(drive, 0);
763         return ide_stopped;
764 }
765
766 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
767                                    struct ide_atapi_pc *pc, struct request *rq,
768                                    u8 opcode)
769 {
770         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
771         unsigned int length = rq->current_nr_sectors;
772
773         ide_init_pc(pc);
774         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
775         pc->c[1] = 1;
776         pc->bh = bh;
777         pc->buf = NULL;
778         pc->buf_size = length * tape->blk_size;
779         pc->req_xfer = pc->buf_size;
780         if (pc->req_xfer == tape->buffer_size)
781                 pc->flags |= PC_FLAG_DMA_OK;
782
783         if (opcode == READ_6) {
784                 pc->c[0] = READ_6;
785                 atomic_set(&bh->b_count, 0);
786         } else if (opcode == WRITE_6) {
787                 pc->c[0] = WRITE_6;
788                 pc->flags |= PC_FLAG_WRITING;
789                 pc->b_data = bh->b_data;
790                 pc->b_count = atomic_read(&bh->b_count);
791         }
792
793         memcpy(rq->cmd, pc->c, 12);
794 }
795
796 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
797                                           struct request *rq, sector_t block)
798 {
799         ide_hwif_t *hwif = drive->hwif;
800         idetape_tape_t *tape = drive->driver_data;
801         struct ide_atapi_pc *pc = NULL;
802         struct request *postponed_rq = tape->postponed_rq;
803         u8 stat;
804
805         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
806                         " current_nr_sectors: %u\n",
807                         (unsigned long long)rq->sector, rq->nr_sectors,
808                         rq->current_nr_sectors);
809
810         if (!blk_special_request(rq)) {
811                 /* We do not support buffer cache originated requests. */
812                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
813                         "request queue (%d)\n", drive->name, rq->cmd_type);
814                 ide_end_request(drive, 0, 0);
815                 return ide_stopped;
816         }
817
818         /* Retry a failed packet command */
819         if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
820                 pc = tape->failed_pc;
821                 goto out;
822         }
823
824         if (postponed_rq != NULL)
825                 if (rq != postponed_rq) {
826                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
827                                         "Two DSC requests were queued\n");
828                         idetape_end_request(drive, 0, 0);
829                         return ide_stopped;
830                 }
831
832         tape->postponed_rq = NULL;
833
834         /*
835          * If the tape is still busy, postpone our request and service
836          * the other device meanwhile.
837          */
838         stat = hwif->tp_ops->read_status(hwif);
839
840         if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
841                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
842
843         if (drive->post_reset == 1) {
844                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
845                 drive->post_reset = 0;
846         }
847
848         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
849             (stat & ATA_DSC) == 0) {
850                 if (postponed_rq == NULL) {
851                         tape->dsc_polling_start = jiffies;
852                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
853                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
854                 } else if (time_after(jiffies, tape->dsc_timeout)) {
855                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
856                                 tape->name);
857                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
858                                 idetape_media_access_finished(drive);
859                                 return ide_stopped;
860                         } else {
861                                 return ide_do_reset(drive);
862                         }
863                 } else if (time_after(jiffies,
864                                         tape->dsc_polling_start +
865                                         IDETAPE_DSC_MA_THRESHOLD))
866                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
867                 idetape_postpone_request(drive);
868                 return ide_stopped;
869         }
870         if (rq->cmd[13] & REQ_IDETAPE_READ) {
871                 pc = &tape->queued_pc;
872                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
873                 goto out;
874         }
875         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
876                 pc = &tape->queued_pc;
877                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
878                 goto out;
879         }
880         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
881                 pc = (struct ide_atapi_pc *) rq->buffer;
882                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
883                 rq->cmd[13] |= REQ_IDETAPE_PC2;
884                 goto out;
885         }
886         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
887                 idetape_media_access_finished(drive);
888                 return ide_stopped;
889         }
890         BUG();
891
892 out:
893         return idetape_issue_pc(drive, pc);
894 }
895
896 /*
897  * The function below uses __get_free_pages to allocate a data buffer of size
898  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
899  * much as possible.
900  *
901  * It returns a pointer to the newly allocated buffer, or NULL in case of
902  * failure.
903  */
904 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
905                                                   int full, int clear)
906 {
907         struct idetape_bh *prev_bh, *bh, *merge_bh;
908         int pages = tape->pages_per_buffer;
909         unsigned int order, b_allocd;
910         char *b_data = NULL;
911
912         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
913         bh = merge_bh;
914         if (bh == NULL)
915                 goto abort;
916
917         order = fls(pages) - 1;
918         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
919         if (!bh->b_data)
920                 goto abort;
921         b_allocd = (1 << order) * PAGE_SIZE;
922         pages &= (order-1);
923
924         if (clear)
925                 memset(bh->b_data, 0, b_allocd);
926         bh->b_reqnext = NULL;
927         bh->b_size = b_allocd;
928         atomic_set(&bh->b_count, full ? bh->b_size : 0);
929
930         while (pages) {
931                 order = fls(pages) - 1;
932                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
933                 if (!b_data)
934                         goto abort;
935                 b_allocd = (1 << order) * PAGE_SIZE;
936
937                 if (clear)
938                         memset(b_data, 0, b_allocd);
939
940                 /* newly allocated page frames below buffer header or ...*/
941                 if (bh->b_data == b_data + b_allocd) {
942                         bh->b_size += b_allocd;
943                         bh->b_data -= b_allocd;
944                         if (full)
945                                 atomic_add(b_allocd, &bh->b_count);
946                         continue;
947                 }
948                 /* they are above the header */
949                 if (b_data == bh->b_data + bh->b_size) {
950                         bh->b_size += b_allocd;
951                         if (full)
952                                 atomic_add(b_allocd, &bh->b_count);
953                         continue;
954                 }
955                 prev_bh = bh;
956                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
957                 if (!bh) {
958                         free_pages((unsigned long) b_data, order);
959                         goto abort;
960                 }
961                 bh->b_reqnext = NULL;
962                 bh->b_data = b_data;
963                 bh->b_size = b_allocd;
964                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
965                 prev_bh->b_reqnext = bh;
966
967                 pages &= (order-1);
968         }
969
970         bh->b_size -= tape->excess_bh_size;
971         if (full)
972                 atomic_sub(tape->excess_bh_size, &bh->b_count);
973         return merge_bh;
974 abort:
975         ide_tape_kfree_buffer(tape);
976         return NULL;
977 }
978
979 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
980                                         const char __user *buf, int n)
981 {
982         struct idetape_bh *bh = tape->bh;
983         int count;
984         int ret = 0;
985
986         while (n) {
987                 if (bh == NULL) {
988                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
989                                         __func__);
990                         return 1;
991                 }
992                 count = min((unsigned int)
993                                 (bh->b_size - atomic_read(&bh->b_count)),
994                                 (unsigned int)n);
995                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
996                                 count))
997                         ret = 1;
998                 n -= count;
999                 atomic_add(count, &bh->b_count);
1000                 buf += count;
1001                 if (atomic_read(&bh->b_count) == bh->b_size) {
1002                         bh = bh->b_reqnext;
1003                         if (bh)
1004                                 atomic_set(&bh->b_count, 0);
1005                 }
1006         }
1007         tape->bh = bh;
1008         return ret;
1009 }
1010
1011 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1012                                       int n)
1013 {
1014         struct idetape_bh *bh = tape->bh;
1015         int count;
1016         int ret = 0;
1017
1018         while (n) {
1019                 if (bh == NULL) {
1020                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1021                                         __func__);
1022                         return 1;
1023                 }
1024                 count = min(tape->b_count, n);
1025                 if  (copy_to_user(buf, tape->b_data, count))
1026                         ret = 1;
1027                 n -= count;
1028                 tape->b_data += count;
1029                 tape->b_count -= count;
1030                 buf += count;
1031                 if (!tape->b_count) {
1032                         bh = bh->b_reqnext;
1033                         tape->bh = bh;
1034                         if (bh) {
1035                                 tape->b_data = bh->b_data;
1036                                 tape->b_count = atomic_read(&bh->b_count);
1037                         }
1038                 }
1039         }
1040         return ret;
1041 }
1042
1043 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1044 {
1045         struct idetape_bh *bh = tape->merge_bh;
1046         tape->bh = tape->merge_bh;
1047
1048         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1049                 atomic_set(&bh->b_count, 0);
1050         else {
1051                 tape->b_data = bh->b_data;
1052                 tape->b_count = atomic_read(&bh->b_count);
1053         }
1054 }
1055
1056 /*
1057  * Write a filemark if write_filemark=1. Flush the device buffers without
1058  * writing a filemark otherwise.
1059  */
1060 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1061                 struct ide_atapi_pc *pc, int write_filemark)
1062 {
1063         ide_init_pc(pc);
1064         pc->c[0] = WRITE_FILEMARKS;
1065         pc->c[4] = write_filemark;
1066         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1067 }
1068
1069 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1070 {
1071         idetape_tape_t *tape = drive->driver_data;
1072         struct gendisk *disk = tape->disk;
1073         int load_attempted = 0;
1074
1075         /* Wait for the tape to become ready */
1076         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1077         timeout += jiffies;
1078         while (time_before(jiffies, timeout)) {
1079                 if (ide_do_test_unit_ready(drive, disk) == 0)
1080                         return 0;
1081                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1082                     || (tape->asc == 0x3A)) {
1083                         /* no media */
1084                         if (load_attempted)
1085                                 return -ENOMEDIUM;
1086                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1087                         load_attempted = 1;
1088                 /* not about to be ready */
1089                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1090                              (tape->ascq == 1 || tape->ascq == 8)))
1091                         return -EIO;
1092                 msleep(100);
1093         }
1094         return -EIO;
1095 }
1096
1097 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1098 {
1099         struct ide_tape_obj *tape = drive->driver_data;
1100         struct ide_atapi_pc pc;
1101         int rc;
1102
1103         idetape_create_write_filemark_cmd(drive, &pc, 0);
1104         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1105         if (rc)
1106                 return rc;
1107         idetape_wait_ready(drive, 60 * 5 * HZ);
1108         return 0;
1109 }
1110
1111 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1112 {
1113         ide_init_pc(pc);
1114         pc->c[0] = READ_POSITION;
1115         pc->req_xfer = 20;
1116 }
1117
1118 static int idetape_read_position(ide_drive_t *drive)
1119 {
1120         idetape_tape_t *tape = drive->driver_data;
1121         struct ide_atapi_pc pc;
1122         int position;
1123
1124         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1125
1126         idetape_create_read_position_cmd(&pc);
1127         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1128                 return -1;
1129         position = tape->first_frame;
1130         return position;
1131 }
1132
1133 static void idetape_create_locate_cmd(ide_drive_t *drive,
1134                 struct ide_atapi_pc *pc,
1135                 unsigned int block, u8 partition, int skip)
1136 {
1137         ide_init_pc(pc);
1138         pc->c[0] = POSITION_TO_ELEMENT;
1139         pc->c[1] = 2;
1140         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1141         pc->c[8] = partition;
1142         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1143 }
1144
1145 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1146 {
1147         idetape_tape_t *tape = drive->driver_data;
1148
1149         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1150                 return;
1151
1152         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1153         tape->merge_bh_size = 0;
1154         if (tape->merge_bh != NULL) {
1155                 ide_tape_kfree_buffer(tape);
1156                 tape->merge_bh = NULL;
1157         }
1158
1159         tape->chrdev_dir = IDETAPE_DIR_NONE;
1160 }
1161
1162 /*
1163  * Position the tape to the requested block using the LOCATE packet command.
1164  * A READ POSITION command is then issued to check where we are positioned. Like
1165  * all higher level operations, we queue the commands at the tail of the request
1166  * queue and wait for their completion.
1167  */
1168 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1169                 u8 partition, int skip)
1170 {
1171         idetape_tape_t *tape = drive->driver_data;
1172         struct gendisk *disk = tape->disk;
1173         int retval;
1174         struct ide_atapi_pc pc;
1175
1176         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1177                 __ide_tape_discard_merge_buffer(drive);
1178         idetape_wait_ready(drive, 60 * 5 * HZ);
1179         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1180         retval = ide_queue_pc_tail(drive, disk, &pc);
1181         if (retval)
1182                 return (retval);
1183
1184         idetape_create_read_position_cmd(&pc);
1185         return ide_queue_pc_tail(drive, disk, &pc);
1186 }
1187
1188 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1189                                           int restore_position)
1190 {
1191         idetape_tape_t *tape = drive->driver_data;
1192         int seek, position;
1193
1194         __ide_tape_discard_merge_buffer(drive);
1195         if (restore_position) {
1196                 position = idetape_read_position(drive);
1197                 seek = position > 0 ? position : 0;
1198                 if (idetape_position_tape(drive, seek, 0, 0)) {
1199                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1200                                          " %s\n", tape->name, __func__);
1201                         return;
1202                 }
1203         }
1204 }
1205
1206 /*
1207  * Generate a read/write request for the block device interface and wait for it
1208  * to be serviced.
1209  */
1210 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1211                                  struct idetape_bh *bh)
1212 {
1213         idetape_tape_t *tape = drive->driver_data;
1214         struct request *rq;
1215         int ret, errors;
1216
1217         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1218
1219         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1220         rq->cmd_type = REQ_TYPE_SPECIAL;
1221         rq->cmd[13] = cmd;
1222         rq->rq_disk = tape->disk;
1223         rq->special = (void *)bh;
1224         rq->sector = tape->first_frame;
1225         rq->nr_sectors = blocks;
1226         rq->current_nr_sectors = blocks;
1227         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1228
1229         errors = rq->errors;
1230         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1231         blk_put_request(rq);
1232
1233         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1234                 return 0;
1235
1236         if (tape->merge_bh)
1237                 idetape_init_merge_buffer(tape);
1238         if (errors == IDETAPE_ERROR_GENERAL)
1239                 return -EIO;
1240         return ret;
1241 }
1242
1243 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1244 {
1245         ide_init_pc(pc);
1246         pc->c[0] = INQUIRY;
1247         pc->c[4] = 254;
1248         pc->req_xfer = 254;
1249 }
1250
1251 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1252                 struct ide_atapi_pc *pc)
1253 {
1254         ide_init_pc(pc);
1255         pc->c[0] = REZERO_UNIT;
1256         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1257 }
1258
1259 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1260 {
1261         ide_init_pc(pc);
1262         pc->c[0] = ERASE;
1263         pc->c[1] = 1;
1264         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1265 }
1266
1267 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1268 {
1269         ide_init_pc(pc);
1270         pc->c[0] = SPACE;
1271         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1272         pc->c[1] = cmd;
1273         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1274 }
1275
1276 /* Queue up a character device originated write request. */
1277 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1278 {
1279         idetape_tape_t *tape = drive->driver_data;
1280
1281         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1282
1283         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1284                                      blocks, tape->merge_bh);
1285 }
1286
1287 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1288 {
1289         idetape_tape_t *tape = drive->driver_data;
1290         int blocks, min;
1291         struct idetape_bh *bh;
1292
1293         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1294                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1295                                 " but we are not writing.\n");
1296                 return;
1297         }
1298         if (tape->merge_bh_size > tape->buffer_size) {
1299                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1300                 tape->merge_bh_size = tape->buffer_size;
1301         }
1302         if (tape->merge_bh_size) {
1303                 blocks = tape->merge_bh_size / tape->blk_size;
1304                 if (tape->merge_bh_size % tape->blk_size) {
1305                         unsigned int i;
1306
1307                         blocks++;
1308                         i = tape->blk_size - tape->merge_bh_size %
1309                                 tape->blk_size;
1310                         bh = tape->bh->b_reqnext;
1311                         while (bh) {
1312                                 atomic_set(&bh->b_count, 0);
1313                                 bh = bh->b_reqnext;
1314                         }
1315                         bh = tape->bh;
1316                         while (i) {
1317                                 if (bh == NULL) {
1318                                         printk(KERN_INFO "ide-tape: bug,"
1319                                                          " bh NULL\n");
1320                                         break;
1321                                 }
1322                                 min = min(i, (unsigned int)(bh->b_size -
1323                                                 atomic_read(&bh->b_count)));
1324                                 memset(bh->b_data + atomic_read(&bh->b_count),
1325                                                 0, min);
1326                                 atomic_add(min, &bh->b_count);
1327                                 i -= min;
1328                                 bh = bh->b_reqnext;
1329                         }
1330                 }
1331                 (void) idetape_add_chrdev_write_request(drive, blocks);
1332                 tape->merge_bh_size = 0;
1333         }
1334         if (tape->merge_bh != NULL) {
1335                 ide_tape_kfree_buffer(tape);
1336                 tape->merge_bh = NULL;
1337         }
1338         tape->chrdev_dir = IDETAPE_DIR_NONE;
1339 }
1340
1341 static int idetape_init_read(ide_drive_t *drive)
1342 {
1343         idetape_tape_t *tape = drive->driver_data;
1344         int bytes_read;
1345
1346         /* Initialize read operation */
1347         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1348                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1349                         ide_tape_flush_merge_buffer(drive);
1350                         idetape_flush_tape_buffers(drive);
1351                 }
1352                 if (tape->merge_bh || tape->merge_bh_size) {
1353                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1354                                          " 0 now\n");
1355                         tape->merge_bh_size = 0;
1356                 }
1357                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1358                 if (!tape->merge_bh)
1359                         return -ENOMEM;
1360                 tape->chrdev_dir = IDETAPE_DIR_READ;
1361
1362                 /*
1363                  * Issue a read 0 command to ensure that DSC handshake is
1364                  * switched from completion mode to buffer available mode.
1365                  * No point in issuing this if DSC overlap isn't supported, some
1366                  * drives (Seagate STT3401A) will return an error.
1367                  */
1368                 if (drive->dsc_overlap) {
1369                         bytes_read = idetape_queue_rw_tail(drive,
1370                                                         REQ_IDETAPE_READ, 0,
1371                                                         tape->merge_bh);
1372                         if (bytes_read < 0) {
1373                                 ide_tape_kfree_buffer(tape);
1374                                 tape->merge_bh = NULL;
1375                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1376                                 return bytes_read;
1377                         }
1378                 }
1379         }
1380
1381         return 0;
1382 }
1383
1384 /* called from idetape_chrdev_read() to service a chrdev read request. */
1385 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1386 {
1387         idetape_tape_t *tape = drive->driver_data;
1388
1389         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1390
1391         /* If we are at a filemark, return a read length of 0 */
1392         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1393                 return 0;
1394
1395         idetape_init_read(drive);
1396
1397         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1398                                      tape->merge_bh);
1399 }
1400
1401 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1402 {
1403         idetape_tape_t *tape = drive->driver_data;
1404         struct idetape_bh *bh;
1405         int blocks;
1406
1407         while (bcount) {
1408                 unsigned int count;
1409
1410                 bh = tape->merge_bh;
1411                 count = min(tape->buffer_size, bcount);
1412                 bcount -= count;
1413                 blocks = count / tape->blk_size;
1414                 while (count) {
1415                         atomic_set(&bh->b_count,
1416                                    min(count, (unsigned int)bh->b_size));
1417                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1418                         count -= atomic_read(&bh->b_count);
1419                         bh = bh->b_reqnext;
1420                 }
1421                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1422                                       tape->merge_bh);
1423         }
1424 }
1425
1426 /*
1427  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1428  * currently support only one partition.
1429  */
1430 static int idetape_rewind_tape(ide_drive_t *drive)
1431 {
1432         struct ide_tape_obj *tape = drive->driver_data;
1433         struct gendisk *disk = tape->disk;
1434         int retval;
1435         struct ide_atapi_pc pc;
1436
1437         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1438
1439         idetape_create_rewind_cmd(drive, &pc);
1440         retval = ide_queue_pc_tail(drive, disk, &pc);
1441         if (retval)
1442                 return retval;
1443
1444         idetape_create_read_position_cmd(&pc);
1445         retval = ide_queue_pc_tail(drive, disk, &pc);
1446         if (retval)
1447                 return retval;
1448         return 0;
1449 }
1450
1451 /* mtio.h compatible commands should be issued to the chrdev interface. */
1452 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1453                                 unsigned long arg)
1454 {
1455         idetape_tape_t *tape = drive->driver_data;
1456         void __user *argp = (void __user *)arg;
1457
1458         struct idetape_config {
1459                 int dsc_rw_frequency;
1460                 int dsc_media_access_frequency;
1461                 int nr_stages;
1462         } config;
1463
1464         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1465
1466         switch (cmd) {
1467         case 0x0340:
1468                 if (copy_from_user(&config, argp, sizeof(config)))
1469                         return -EFAULT;
1470                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1471                 break;
1472         case 0x0350:
1473                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1474                 config.nr_stages = 1;
1475                 if (copy_to_user(argp, &config, sizeof(config)))
1476                         return -EFAULT;
1477                 break;
1478         default:
1479                 return -EIO;
1480         }
1481         return 0;
1482 }
1483
1484 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1485                                         int mt_count)
1486 {
1487         idetape_tape_t *tape = drive->driver_data;
1488         struct gendisk *disk = tape->disk;
1489         struct ide_atapi_pc pc;
1490         int retval, count = 0;
1491         int sprev = !!(tape->caps[4] & 0x20);
1492
1493         if (mt_count == 0)
1494                 return 0;
1495         if (MTBSF == mt_op || MTBSFM == mt_op) {
1496                 if (!sprev)
1497                         return -EIO;
1498                 mt_count = -mt_count;
1499         }
1500
1501         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1502                 tape->merge_bh_size = 0;
1503                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1504                         ++count;
1505                 ide_tape_discard_merge_buffer(drive, 0);
1506         }
1507
1508         switch (mt_op) {
1509         case MTFSF:
1510         case MTBSF:
1511                 idetape_create_space_cmd(&pc, mt_count - count,
1512                                          IDETAPE_SPACE_OVER_FILEMARK);
1513                 return ide_queue_pc_tail(drive, disk, &pc);
1514         case MTFSFM:
1515         case MTBSFM:
1516                 if (!sprev)
1517                         return -EIO;
1518                 retval = idetape_space_over_filemarks(drive, MTFSF,
1519                                                       mt_count - count);
1520                 if (retval)
1521                         return retval;
1522                 count = (MTBSFM == mt_op ? 1 : -1);
1523                 return idetape_space_over_filemarks(drive, MTFSF, count);
1524         default:
1525                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1526                                 mt_op);
1527                 return -EIO;
1528         }
1529 }
1530
1531 /*
1532  * Our character device read / write functions.
1533  *
1534  * The tape is optimized to maximize throughput when it is transferring an
1535  * integral number of the "continuous transfer limit", which is a parameter of
1536  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1537  *
1538  * As of version 1.3 of the driver, the character device provides an abstract
1539  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1540  * same backup/restore procedure is supported. The driver will internally
1541  * convert the requests to the recommended transfer unit, so that an unmatch
1542  * between the user's block size to the recommended size will only result in a
1543  * (slightly) increased driver overhead, but will no longer hit performance.
1544  * This is not applicable to Onstream.
1545  */
1546 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1547                                    size_t count, loff_t *ppos)
1548 {
1549         struct ide_tape_obj *tape = ide_tape_f(file);
1550         ide_drive_t *drive = tape->drive;
1551         ssize_t bytes_read, temp, actually_read = 0, rc;
1552         ssize_t ret = 0;
1553         u16 ctl = *(u16 *)&tape->caps[12];
1554
1555         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1556
1557         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1558                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1559                         if (count > tape->blk_size &&
1560                             (count % tape->blk_size) == 0)
1561                                 tape->user_bs_factor = count / tape->blk_size;
1562         }
1563         rc = idetape_init_read(drive);
1564         if (rc < 0)
1565                 return rc;
1566         if (count == 0)
1567                 return (0);
1568         if (tape->merge_bh_size) {
1569                 actually_read = min((unsigned int)(tape->merge_bh_size),
1570                                     (unsigned int)count);
1571                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1572                         ret = -EFAULT;
1573                 buf += actually_read;
1574                 tape->merge_bh_size -= actually_read;
1575                 count -= actually_read;
1576         }
1577         while (count >= tape->buffer_size) {
1578                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1579                 if (bytes_read <= 0)
1580                         goto finish;
1581                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1582                         ret = -EFAULT;
1583                 buf += bytes_read;
1584                 count -= bytes_read;
1585                 actually_read += bytes_read;
1586         }
1587         if (count) {
1588                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1589                 if (bytes_read <= 0)
1590                         goto finish;
1591                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1592                 if (idetape_copy_stage_to_user(tape, buf, temp))
1593                         ret = -EFAULT;
1594                 actually_read += temp;
1595                 tape->merge_bh_size = bytes_read-temp;
1596         }
1597 finish:
1598         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1599                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1600
1601                 idetape_space_over_filemarks(drive, MTFSF, 1);
1602                 return 0;
1603         }
1604
1605         return ret ? ret : actually_read;
1606 }
1607
1608 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1609                                      size_t count, loff_t *ppos)
1610 {
1611         struct ide_tape_obj *tape = ide_tape_f(file);
1612         ide_drive_t *drive = tape->drive;
1613         ssize_t actually_written = 0;
1614         ssize_t ret = 0;
1615         u16 ctl = *(u16 *)&tape->caps[12];
1616
1617         /* The drive is write protected. */
1618         if (tape->write_prot)
1619                 return -EACCES;
1620
1621         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1622
1623         /* Initialize write operation */
1624         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1625                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1626                         ide_tape_discard_merge_buffer(drive, 1);
1627                 if (tape->merge_bh || tape->merge_bh_size) {
1628                         printk(KERN_ERR "ide-tape: merge_bh_size "
1629                                 "should be 0 now\n");
1630                         tape->merge_bh_size = 0;
1631                 }
1632                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1633                 if (!tape->merge_bh)
1634                         return -ENOMEM;
1635                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1636                 idetape_init_merge_buffer(tape);
1637
1638                 /*
1639                  * Issue a write 0 command to ensure that DSC handshake is
1640                  * switched from completion mode to buffer available mode. No
1641                  * point in issuing this if DSC overlap isn't supported, some
1642                  * drives (Seagate STT3401A) will return an error.
1643                  */
1644                 if (drive->dsc_overlap) {
1645                         ssize_t retval = idetape_queue_rw_tail(drive,
1646                                                         REQ_IDETAPE_WRITE, 0,
1647                                                         tape->merge_bh);
1648                         if (retval < 0) {
1649                                 ide_tape_kfree_buffer(tape);
1650                                 tape->merge_bh = NULL;
1651                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1652                                 return retval;
1653                         }
1654                 }
1655         }
1656         if (count == 0)
1657                 return (0);
1658         if (tape->merge_bh_size) {
1659                 if (tape->merge_bh_size >= tape->buffer_size) {
1660                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1661                         tape->merge_bh_size = 0;
1662                 }
1663                 actually_written = min((unsigned int)
1664                                 (tape->buffer_size - tape->merge_bh_size),
1665                                 (unsigned int)count);
1666                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1667                                 ret = -EFAULT;
1668                 buf += actually_written;
1669                 tape->merge_bh_size += actually_written;
1670                 count -= actually_written;
1671
1672                 if (tape->merge_bh_size == tape->buffer_size) {
1673                         ssize_t retval;
1674                         tape->merge_bh_size = 0;
1675                         retval = idetape_add_chrdev_write_request(drive, ctl);
1676                         if (retval <= 0)
1677                                 return (retval);
1678                 }
1679         }
1680         while (count >= tape->buffer_size) {
1681                 ssize_t retval;
1682                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1683                         ret = -EFAULT;
1684                 buf += tape->buffer_size;
1685                 count -= tape->buffer_size;
1686                 retval = idetape_add_chrdev_write_request(drive, ctl);
1687                 actually_written += tape->buffer_size;
1688                 if (retval <= 0)
1689                         return (retval);
1690         }
1691         if (count) {
1692                 actually_written += count;
1693                 if (idetape_copy_stage_from_user(tape, buf, count))
1694                         ret = -EFAULT;
1695                 tape->merge_bh_size += count;
1696         }
1697         return ret ? ret : actually_written;
1698 }
1699
1700 static int idetape_write_filemark(ide_drive_t *drive)
1701 {
1702         struct ide_tape_obj *tape = drive->driver_data;
1703         struct ide_atapi_pc pc;
1704
1705         /* Write a filemark */
1706         idetape_create_write_filemark_cmd(drive, &pc, 1);
1707         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1708                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1709                 return -EIO;
1710         }
1711         return 0;
1712 }
1713
1714 /*
1715  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1716  * requested.
1717  *
1718  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1719  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1720  * usually not supported.
1721  *
1722  * The following commands are currently not supported:
1723  *
1724  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1725  * MT_ST_WRITE_THRESHOLD.
1726  */
1727 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1728 {
1729         idetape_tape_t *tape = drive->driver_data;
1730         struct gendisk *disk = tape->disk;
1731         struct ide_atapi_pc pc;
1732         int i, retval;
1733
1734         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1735                         mt_op, mt_count);
1736
1737         switch (mt_op) {
1738         case MTFSF:
1739         case MTFSFM:
1740         case MTBSF:
1741         case MTBSFM:
1742                 if (!mt_count)
1743                         return 0;
1744                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1745         default:
1746                 break;
1747         }
1748
1749         switch (mt_op) {
1750         case MTWEOF:
1751                 if (tape->write_prot)
1752                         return -EACCES;
1753                 ide_tape_discard_merge_buffer(drive, 1);
1754                 for (i = 0; i < mt_count; i++) {
1755                         retval = idetape_write_filemark(drive);
1756                         if (retval)
1757                                 return retval;
1758                 }
1759                 return 0;
1760         case MTREW:
1761                 ide_tape_discard_merge_buffer(drive, 0);
1762                 if (idetape_rewind_tape(drive))
1763                         return -EIO;
1764                 return 0;
1765         case MTLOAD:
1766                 ide_tape_discard_merge_buffer(drive, 0);
1767                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1768         case MTUNLOAD:
1769         case MTOFFL:
1770                 /*
1771                  * If door is locked, attempt to unlock before
1772                  * attempting to eject.
1773                  */
1774                 if (tape->door_locked) {
1775                         if (!ide_set_media_lock(drive, disk, 0))
1776                                 tape->door_locked = DOOR_UNLOCKED;
1777                 }
1778                 ide_tape_discard_merge_buffer(drive, 0);
1779                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1780                 if (!retval)
1781                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1782                 return retval;
1783         case MTNOP:
1784                 ide_tape_discard_merge_buffer(drive, 0);
1785                 return idetape_flush_tape_buffers(drive);
1786         case MTRETEN:
1787                 ide_tape_discard_merge_buffer(drive, 0);
1788                 return ide_do_start_stop(drive, disk,
1789                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1790         case MTEOM:
1791                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1792                 return ide_queue_pc_tail(drive, disk, &pc);
1793         case MTERASE:
1794                 (void)idetape_rewind_tape(drive);
1795                 idetape_create_erase_cmd(&pc);
1796                 return ide_queue_pc_tail(drive, disk, &pc);
1797         case MTSETBLK:
1798                 if (mt_count) {
1799                         if (mt_count < tape->blk_size ||
1800                             mt_count % tape->blk_size)
1801                                 return -EIO;
1802                         tape->user_bs_factor = mt_count / tape->blk_size;
1803                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1804                 } else
1805                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1806                 return 0;
1807         case MTSEEK:
1808                 ide_tape_discard_merge_buffer(drive, 0);
1809                 return idetape_position_tape(drive,
1810                         mt_count * tape->user_bs_factor, tape->partition, 0);
1811         case MTSETPART:
1812                 ide_tape_discard_merge_buffer(drive, 0);
1813                 return idetape_position_tape(drive, 0, mt_count, 0);
1814         case MTFSR:
1815         case MTBSR:
1816         case MTLOCK:
1817                 retval = ide_set_media_lock(drive, disk, 1);
1818                 if (retval)
1819                         return retval;
1820                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1821                 return 0;
1822         case MTUNLOCK:
1823                 retval = ide_set_media_lock(drive, disk, 0);
1824                 if (retval)
1825                         return retval;
1826                 tape->door_locked = DOOR_UNLOCKED;
1827                 return 0;
1828         default:
1829                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1830                                 mt_op);
1831                 return -EIO;
1832         }
1833 }
1834
1835 /*
1836  * Our character device ioctls. General mtio.h magnetic io commands are
1837  * supported here, and not in the corresponding block interface. Our own
1838  * ide-tape ioctls are supported on both interfaces.
1839  */
1840 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1841                                 unsigned int cmd, unsigned long arg)
1842 {
1843         struct ide_tape_obj *tape = ide_tape_f(file);
1844         ide_drive_t *drive = tape->drive;
1845         struct mtop mtop;
1846         struct mtget mtget;
1847         struct mtpos mtpos;
1848         int block_offset = 0, position = tape->first_frame;
1849         void __user *argp = (void __user *)arg;
1850
1851         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1852
1853         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1854                 ide_tape_flush_merge_buffer(drive);
1855                 idetape_flush_tape_buffers(drive);
1856         }
1857         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1858                 block_offset = tape->merge_bh_size /
1859                         (tape->blk_size * tape->user_bs_factor);
1860                 position = idetape_read_position(drive);
1861                 if (position < 0)
1862                         return -EIO;
1863         }
1864         switch (cmd) {
1865         case MTIOCTOP:
1866                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1867                         return -EFAULT;
1868                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1869         case MTIOCGET:
1870                 memset(&mtget, 0, sizeof(struct mtget));
1871                 mtget.mt_type = MT_ISSCSI2;
1872                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1873                 mtget.mt_dsreg =
1874                         ((tape->blk_size * tape->user_bs_factor)
1875                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1876
1877                 if (tape->drv_write_prot)
1878                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1879
1880                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1881                         return -EFAULT;
1882                 return 0;
1883         case MTIOCPOS:
1884                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1885                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1886                         return -EFAULT;
1887                 return 0;
1888         default:
1889                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1890                         ide_tape_discard_merge_buffer(drive, 1);
1891                 return idetape_blkdev_ioctl(drive, cmd, arg);
1892         }
1893 }
1894
1895 /*
1896  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1897  * block size with the reported value.
1898  */
1899 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1900 {
1901         idetape_tape_t *tape = drive->driver_data;
1902         struct ide_atapi_pc pc;
1903
1904         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1905         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1906                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1907                 if (tape->blk_size == 0) {
1908                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1909                                             "block size, assuming 32k\n");
1910                         tape->blk_size = 32768;
1911                 }
1912                 return;
1913         }
1914         tape->blk_size = (pc.buf[4 + 5] << 16) +
1915                                 (pc.buf[4 + 6] << 8)  +
1916                                  pc.buf[4 + 7];
1917         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1918 }
1919
1920 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1921 {
1922         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1923         ide_drive_t *drive;
1924         idetape_tape_t *tape;
1925         int retval;
1926
1927         if (i >= MAX_HWIFS * MAX_DRIVES)
1928                 return -ENXIO;
1929
1930         lock_kernel();
1931         tape = ide_tape_chrdev_get(i);
1932         if (!tape) {
1933                 unlock_kernel();
1934                 return -ENXIO;
1935         }
1936
1937         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1938
1939         /*
1940          * We really want to do nonseekable_open(inode, filp); here, but some
1941          * versions of tar incorrectly call lseek on tapes and bail out if that
1942          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1943          */
1944         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1945
1946         drive = tape->drive;
1947
1948         filp->private_data = tape;
1949
1950         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1951                 retval = -EBUSY;
1952                 goto out_put_tape;
1953         }
1954
1955         retval = idetape_wait_ready(drive, 60 * HZ);
1956         if (retval) {
1957                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1958                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1959                 goto out_put_tape;
1960         }
1961
1962         idetape_read_position(drive);
1963         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1964                 (void)idetape_rewind_tape(drive);
1965
1966         /* Read block size and write protect status from drive. */
1967         ide_tape_get_bsize_from_bdesc(drive);
1968
1969         /* Set write protect flag if device is opened as read-only. */
1970         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1971                 tape->write_prot = 1;
1972         else
1973                 tape->write_prot = tape->drv_write_prot;
1974
1975         /* Make sure drive isn't write protected if user wants to write. */
1976         if (tape->write_prot) {
1977                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1978                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1979                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1980                         retval = -EROFS;
1981                         goto out_put_tape;
1982                 }
1983         }
1984
1985         /* Lock the tape drive door so user can't eject. */
1986         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1987                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1988                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1989                                 tape->door_locked = DOOR_LOCKED;
1990                 }
1991         }
1992         unlock_kernel();
1993         return 0;
1994
1995 out_put_tape:
1996         ide_tape_put(tape);
1997         unlock_kernel();
1998         return retval;
1999 }
2000
2001 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2002 {
2003         idetape_tape_t *tape = drive->driver_data;
2004
2005         ide_tape_flush_merge_buffer(drive);
2006         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2007         if (tape->merge_bh != NULL) {
2008                 idetape_pad_zeros(drive, tape->blk_size *
2009                                 (tape->user_bs_factor - 1));
2010                 ide_tape_kfree_buffer(tape);
2011                 tape->merge_bh = NULL;
2012         }
2013         idetape_write_filemark(drive);
2014         idetape_flush_tape_buffers(drive);
2015         idetape_flush_tape_buffers(drive);
2016 }
2017
2018 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2019 {
2020         struct ide_tape_obj *tape = ide_tape_f(filp);
2021         ide_drive_t *drive = tape->drive;
2022         unsigned int minor = iminor(inode);
2023
2024         lock_kernel();
2025         tape = drive->driver_data;
2026
2027         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2028
2029         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2030                 idetape_write_release(drive, minor);
2031         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2032                 if (minor < 128)
2033                         ide_tape_discard_merge_buffer(drive, 1);
2034         }
2035
2036         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2037                 (void) idetape_rewind_tape(drive);
2038         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2039                 if (tape->door_locked == DOOR_LOCKED) {
2040                         if (!ide_set_media_lock(drive, tape->disk, 0))
2041                                 tape->door_locked = DOOR_UNLOCKED;
2042                 }
2043         }
2044         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2045         ide_tape_put(tape);
2046         unlock_kernel();
2047         return 0;
2048 }
2049
2050 static void idetape_get_inquiry_results(ide_drive_t *drive)
2051 {
2052         idetape_tape_t *tape = drive->driver_data;
2053         struct ide_atapi_pc pc;
2054         char fw_rev[4], vendor_id[8], product_id[16];
2055
2056         idetape_create_inquiry_cmd(&pc);
2057         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2058                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2059                                 tape->name);
2060                 return;
2061         }
2062         memcpy(vendor_id, &pc.buf[8], 8);
2063         memcpy(product_id, &pc.buf[16], 16);
2064         memcpy(fw_rev, &pc.buf[32], 4);
2065
2066         ide_fixstring(vendor_id, 8, 0);
2067         ide_fixstring(product_id, 16, 0);
2068         ide_fixstring(fw_rev, 4, 0);
2069
2070         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2071                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2072 }
2073
2074 /*
2075  * Ask the tape about its various parameters. In particular, we will adjust our
2076  * data transfer buffer size to the recommended value as returned by the tape.
2077  */
2078 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2079 {
2080         idetape_tape_t *tape = drive->driver_data;
2081         struct ide_atapi_pc pc;
2082         u8 *caps;
2083         u8 speed, max_speed;
2084
2085         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2086         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2087                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2088                                 " some default values\n");
2089                 tape->blk_size = 512;
2090                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2091                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2092                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2093                 return;
2094         }
2095         caps = pc.buf + 4 + pc.buf[3];
2096
2097         /* convert to host order and save for later use */
2098         speed = be16_to_cpup((__be16 *)&caps[14]);
2099         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2100
2101         *(u16 *)&caps[8] = max_speed;
2102         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2103         *(u16 *)&caps[14] = speed;
2104         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2105
2106         if (!speed) {
2107                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2108                                 "(assuming 650KB/sec)\n", drive->name);
2109                 *(u16 *)&caps[14] = 650;
2110         }
2111         if (!max_speed) {
2112                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2113                                 "(assuming 650KB/sec)\n", drive->name);
2114                 *(u16 *)&caps[8] = 650;
2115         }
2116
2117         memcpy(&tape->caps, caps, 20);
2118
2119         /* device lacks locking support according to capabilities page */
2120         if ((caps[6] & 1) == 0)
2121                 drive->atapi_flags |= IDE_AFLAG_NO_DOORLOCK;
2122
2123         if (caps[7] & 0x02)
2124                 tape->blk_size = 512;
2125         else if (caps[7] & 0x04)
2126                 tape->blk_size = 1024;
2127 }
2128
2129 #ifdef CONFIG_IDE_PROC_FS
2130 #define ide_tape_devset_get(name, field) \
2131 static int get_##name(ide_drive_t *drive) \
2132 { \
2133         idetape_tape_t *tape = drive->driver_data; \
2134         return tape->field; \
2135 }
2136
2137 #define ide_tape_devset_set(name, field) \
2138 static int set_##name(ide_drive_t *drive, int arg) \
2139 { \
2140         idetape_tape_t *tape = drive->driver_data; \
2141         tape->field = arg; \
2142         return 0; \
2143 }
2144
2145 #define ide_tape_devset_rw_field(_name, _field) \
2146 ide_tape_devset_get(_name, _field) \
2147 ide_tape_devset_set(_name, _field) \
2148 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2149
2150 #define ide_tape_devset_r_field(_name, _field) \
2151 ide_tape_devset_get(_name, _field) \
2152 IDE_DEVSET(_name, 0, get_##_name, NULL)
2153
2154 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2155 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2156 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2157 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2158
2159 ide_devset_rw_field(dsc_overlap, dsc_overlap);
2160
2161 ide_tape_devset_rw_field(debug_mask, debug_mask);
2162 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2163
2164 ide_tape_devset_r_field(avg_speed, avg_speed);
2165 ide_tape_devset_r_field(speed, caps[14]);
2166 ide_tape_devset_r_field(buffer, caps[16]);
2167 ide_tape_devset_r_field(buffer_size, buffer_size);
2168
2169 static const struct ide_proc_devset idetape_settings[] = {
2170         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2171         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2172         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2173         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2174         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2175         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2176         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2177                                         mulf_tdsc, divf_tdsc),
2178         { 0 },
2179 };
2180 #endif
2181
2182 /*
2183  * The function below is called to:
2184  *
2185  * 1. Initialize our various state variables.
2186  * 2. Ask the tape for its capabilities.
2187  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2188  * is chosen based on the recommendation which we received in step 2.
2189  *
2190  * Note that at this point ide.c already assigned us an irq, so that we can
2191  * queue requests here and wait for their completion.
2192  */
2193 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2194 {
2195         unsigned long t;
2196         int speed;
2197         int buffer_size;
2198         u8 gcw[2];
2199         u16 *ctl = (u16 *)&tape->caps[12];
2200
2201         drive->pc_callback       = ide_tape_callback;
2202         drive->pc_update_buffers = idetape_update_buffers;
2203         drive->pc_io_buffers     = ide_tape_io_buffers;
2204
2205         spin_lock_init(&tape->lock);
2206         drive->dsc_overlap = 1;
2207         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2208                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2209                                  tape->name);
2210                 drive->dsc_overlap = 0;
2211         }
2212         /* Seagate Travan drives do not support DSC overlap. */
2213         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2214                 drive->dsc_overlap = 0;
2215         tape->minor = minor;
2216         tape->name[0] = 'h';
2217         tape->name[1] = 't';
2218         tape->name[2] = '0' + minor;
2219         tape->chrdev_dir = IDETAPE_DIR_NONE;
2220
2221         *((u16 *)&gcw) = drive->id[ATA_ID_CONFIG];
2222
2223         /* Command packet DRQ type */
2224         if (((gcw[0] & 0x60) >> 5) == 1)
2225                 set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
2226
2227         idetape_get_inquiry_results(drive);
2228         idetape_get_mode_sense_results(drive);
2229         ide_tape_get_bsize_from_bdesc(drive);
2230         tape->user_bs_factor = 1;
2231         tape->buffer_size = *ctl * tape->blk_size;
2232         while (tape->buffer_size > 0xffff) {
2233                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2234                 *ctl /= 2;
2235                 tape->buffer_size = *ctl * tape->blk_size;
2236         }
2237         buffer_size = tape->buffer_size;
2238         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2239         if (buffer_size % PAGE_SIZE) {
2240                 tape->pages_per_buffer++;
2241                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2242         }
2243
2244         /* select the "best" DSC read/write polling freq */
2245         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2246
2247         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2248
2249         /*
2250          * Ensure that the number we got makes sense; limit it within
2251          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2252          */
2253         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2254                                          IDETAPE_DSC_RW_MAX);
2255         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2256                 "%lums tDSC%s\n",
2257                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2258                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2259                 tape->buffer_size / 1024,
2260                 tape->best_dsc_rw_freq * 1000 / HZ,
2261                 drive->using_dma ? ", DMA":"");
2262
2263         ide_proc_register_driver(drive, tape->driver);
2264 }
2265
2266 static void ide_tape_remove(ide_drive_t *drive)
2267 {
2268         idetape_tape_t *tape = drive->driver_data;
2269
2270         ide_proc_unregister_driver(drive, tape->driver);
2271
2272         ide_unregister_region(tape->disk);
2273
2274         ide_tape_put(tape);
2275 }
2276
2277 static void ide_tape_release(struct kref *kref)
2278 {
2279         struct ide_tape_obj *tape = to_ide_tape(kref);
2280         ide_drive_t *drive = tape->drive;
2281         struct gendisk *g = tape->disk;
2282
2283         BUG_ON(tape->merge_bh_size);
2284
2285         drive->dsc_overlap = 0;
2286         drive->driver_data = NULL;
2287         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2288         device_destroy(idetape_sysfs_class,
2289                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2290         idetape_devs[tape->minor] = NULL;
2291         g->private_data = NULL;
2292         put_disk(g);
2293         kfree(tape);
2294 }
2295
2296 #ifdef CONFIG_IDE_PROC_FS
2297 static int proc_idetape_read_name
2298         (char *page, char **start, off_t off, int count, int *eof, void *data)
2299 {
2300         ide_drive_t     *drive = (ide_drive_t *) data;
2301         idetape_tape_t  *tape = drive->driver_data;
2302         char            *out = page;
2303         int             len;
2304
2305         len = sprintf(out, "%s\n", tape->name);
2306         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2307 }
2308
2309 static ide_proc_entry_t idetape_proc[] = {
2310         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2311         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2312         { NULL, 0, NULL, NULL }
2313 };
2314 #endif
2315
2316 static int ide_tape_probe(ide_drive_t *);
2317
2318 static ide_driver_t idetape_driver = {
2319         .gen_driver = {
2320                 .owner          = THIS_MODULE,
2321                 .name           = "ide-tape",
2322                 .bus            = &ide_bus_type,
2323         },
2324         .probe                  = ide_tape_probe,
2325         .remove                 = ide_tape_remove,
2326         .version                = IDETAPE_VERSION,
2327         .media                  = ide_tape,
2328         .do_request             = idetape_do_request,
2329         .end_request            = idetape_end_request,
2330         .error                  = __ide_error,
2331 #ifdef CONFIG_IDE_PROC_FS
2332         .proc                   = idetape_proc,
2333         .settings               = idetape_settings,
2334 #endif
2335 };
2336
2337 /* Our character device supporting functions, passed to register_chrdev. */
2338 static const struct file_operations idetape_fops = {
2339         .owner          = THIS_MODULE,
2340         .read           = idetape_chrdev_read,
2341         .write          = idetape_chrdev_write,
2342         .ioctl          = idetape_chrdev_ioctl,
2343         .open           = idetape_chrdev_open,
2344         .release        = idetape_chrdev_release,
2345 };
2346
2347 static int idetape_open(struct inode *inode, struct file *filp)
2348 {
2349         struct gendisk *disk = inode->i_bdev->bd_disk;
2350         struct ide_tape_obj *tape;
2351
2352         tape = ide_tape_get(disk);
2353         if (!tape)
2354                 return -ENXIO;
2355
2356         return 0;
2357 }
2358
2359 static int idetape_release(struct inode *inode, struct file *filp)
2360 {
2361         struct gendisk *disk = inode->i_bdev->bd_disk;
2362         struct ide_tape_obj *tape = ide_tape_g(disk);
2363
2364         ide_tape_put(tape);
2365
2366         return 0;
2367 }
2368
2369 static int idetape_ioctl(struct inode *inode, struct file *file,
2370                         unsigned int cmd, unsigned long arg)
2371 {
2372         struct block_device *bdev = inode->i_bdev;
2373         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2374         ide_drive_t *drive = tape->drive;
2375         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2376         if (err == -EINVAL)
2377                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2378         return err;
2379 }
2380
2381 static struct block_device_operations idetape_block_ops = {
2382         .owner          = THIS_MODULE,
2383         .open           = idetape_open,
2384         .release        = idetape_release,
2385         .ioctl          = idetape_ioctl,
2386 };
2387
2388 static int ide_tape_probe(ide_drive_t *drive)
2389 {
2390         idetape_tape_t *tape;
2391         struct gendisk *g;
2392         int minor;
2393
2394         if (!strstr("ide-tape", drive->driver_req))
2395                 goto failed;
2396
2397         if (drive->media != ide_tape)
2398                 goto failed;
2399
2400         if (drive->id_read == 1 && !ide_check_atapi_device(drive, DRV_NAME)) {
2401                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2402                                 " the driver\n", drive->name);
2403                 goto failed;
2404         }
2405         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2406         if (tape == NULL) {
2407                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2408                                 drive->name);
2409                 goto failed;
2410         }
2411
2412         g = alloc_disk(1 << PARTN_BITS);
2413         if (!g)
2414                 goto out_free_tape;
2415
2416         ide_init_disk(g, drive);
2417
2418         kref_init(&tape->kref);
2419
2420         tape->drive = drive;
2421         tape->driver = &idetape_driver;
2422         tape->disk = g;
2423
2424         g->private_data = &tape->driver;
2425
2426         drive->driver_data = tape;
2427
2428         mutex_lock(&idetape_ref_mutex);
2429         for (minor = 0; idetape_devs[minor]; minor++)
2430                 ;
2431         idetape_devs[minor] = tape;
2432         mutex_unlock(&idetape_ref_mutex);
2433
2434         idetape_setup(drive, tape, minor);
2435
2436         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2437                               MKDEV(IDETAPE_MAJOR, minor), NULL,
2438                               "%s", tape->name);
2439         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2440                               MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2441                               "n%s", tape->name);
2442
2443         g->fops = &idetape_block_ops;
2444         ide_register_region(g);
2445
2446         return 0;
2447
2448 out_free_tape:
2449         kfree(tape);
2450 failed:
2451         return -ENODEV;
2452 }
2453
2454 static void __exit idetape_exit(void)
2455 {
2456         driver_unregister(&idetape_driver.gen_driver);
2457         class_destroy(idetape_sysfs_class);
2458         unregister_chrdev(IDETAPE_MAJOR, "ht");
2459 }
2460
2461 static int __init idetape_init(void)
2462 {
2463         int error = 1;
2464         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2465         if (IS_ERR(idetape_sysfs_class)) {
2466                 idetape_sysfs_class = NULL;
2467                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2468                 error = -EBUSY;
2469                 goto out;
2470         }
2471
2472         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2473                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2474                                 " interface\n");
2475                 error = -EBUSY;
2476                 goto out_free_class;
2477         }
2478
2479         error = driver_register(&idetape_driver.gen_driver);
2480         if (error)
2481                 goto out_free_driver;
2482
2483         return 0;
2484
2485 out_free_driver:
2486         driver_unregister(&idetape_driver.gen_driver);
2487 out_free_class:
2488         class_destroy(idetape_sysfs_class);
2489 out:
2490         return error;
2491 }
2492
2493 MODULE_ALIAS("ide:*m-tape*");
2494 module_init(idetape_init);
2495 module_exit(idetape_exit);
2496 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2497 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2498 MODULE_LICENSE("GPL");