5d2aa22cd6e471617176ab38624f5b164ccb3f09
[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 static void ide_tape_release(struct kref *);
271
272 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
273 {
274         struct ide_tape_obj *tape = NULL;
275
276         mutex_lock(&idetape_ref_mutex);
277         tape = ide_drv_g(disk, ide_tape_obj);
278         if (tape) {
279                 if (ide_device_get(tape->drive))
280                         tape = NULL;
281                 else
282                         kref_get(&tape->kref);
283         }
284         mutex_unlock(&idetape_ref_mutex);
285         return tape;
286 }
287
288 static void ide_tape_put(struct ide_tape_obj *tape)
289 {
290         ide_drive_t *drive = tape->drive;
291
292         mutex_lock(&idetape_ref_mutex);
293         kref_put(&tape->kref, ide_tape_release);
294         ide_device_put(drive);
295         mutex_unlock(&idetape_ref_mutex);
296 }
297
298 /*
299  * The variables below are used for the character device interface. Additional
300  * state variables are defined in our ide_drive_t structure.
301  */
302 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
303
304 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
305 {
306         struct ide_tape_obj *tape = NULL;
307
308         mutex_lock(&idetape_ref_mutex);
309         tape = idetape_devs[i];
310         if (tape)
311                 kref_get(&tape->kref);
312         mutex_unlock(&idetape_ref_mutex);
313         return tape;
314 }
315
316 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
317                                   unsigned int bcount)
318 {
319         struct idetape_bh *bh = pc->bh;
320         int count;
321
322         while (bcount) {
323                 if (bh == NULL) {
324                         printk(KERN_ERR "ide-tape: bh == NULL in "
325                                 "idetape_input_buffers\n");
326                         ide_pad_transfer(drive, 0, bcount);
327                         return;
328                 }
329                 count = min(
330                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
331                         bcount);
332                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
333                                         atomic_read(&bh->b_count), count);
334                 bcount -= count;
335                 atomic_add(count, &bh->b_count);
336                 if (atomic_read(&bh->b_count) == bh->b_size) {
337                         bh = bh->b_reqnext;
338                         if (bh)
339                                 atomic_set(&bh->b_count, 0);
340                 }
341         }
342         pc->bh = bh;
343 }
344
345 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
346                                    unsigned int bcount)
347 {
348         struct idetape_bh *bh = pc->bh;
349         int count;
350
351         while (bcount) {
352                 if (bh == NULL) {
353                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
354                                         __func__);
355                         return;
356                 }
357                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
358                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
359                 bcount -= count;
360                 pc->b_data += count;
361                 pc->b_count -= count;
362                 if (!pc->b_count) {
363                         bh = bh->b_reqnext;
364                         pc->bh = bh;
365                         if (bh) {
366                                 pc->b_data = bh->b_data;
367                                 pc->b_count = atomic_read(&bh->b_count);
368                         }
369                 }
370         }
371 }
372
373 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
374 {
375         struct idetape_bh *bh = pc->bh;
376         int count;
377         unsigned int bcount = pc->xferred;
378
379         if (pc->flags & PC_FLAG_WRITING)
380                 return;
381         while (bcount) {
382                 if (bh == NULL) {
383                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
384                                         __func__);
385                         return;
386                 }
387                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
388                 atomic_set(&bh->b_count, count);
389                 if (atomic_read(&bh->b_count) == bh->b_size)
390                         bh = bh->b_reqnext;
391                 bcount -= count;
392         }
393         pc->bh = bh;
394 }
395
396 /*
397  * called on each failed packet command retry to analyze the request sense. We
398  * currently do not utilize this information.
399  */
400 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
401 {
402         idetape_tape_t *tape = drive->driver_data;
403         struct ide_atapi_pc *pc = tape->failed_pc;
404
405         tape->sense_key = sense[2] & 0xF;
406         tape->asc       = sense[12];
407         tape->ascq      = sense[13];
408
409         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
410                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
411
412         /* Correct pc->xferred by asking the tape.       */
413         if (pc->flags & PC_FLAG_DMA_ERROR) {
414                 pc->xferred = pc->req_xfer -
415                         tape->blk_size *
416                         get_unaligned_be32(&sense[3]);
417                 idetape_update_buffers(drive, pc);
418         }
419
420         /*
421          * If error was the result of a zero-length read or write command,
422          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
423          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
424          */
425         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
426             /* length == 0 */
427             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
428                 if (tape->sense_key == 5) {
429                         /* don't report an error, everything's ok */
430                         pc->error = 0;
431                         /* don't retry read/write */
432                         pc->flags |= PC_FLAG_ABORT;
433                 }
434         }
435         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
436                 pc->error = IDETAPE_ERROR_FILEMARK;
437                 pc->flags |= PC_FLAG_ABORT;
438         }
439         if (pc->c[0] == WRITE_6) {
440                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
441                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
442                         pc->error = IDETAPE_ERROR_EOD;
443                         pc->flags |= PC_FLAG_ABORT;
444                 }
445         }
446         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
447                 if (tape->sense_key == 8) {
448                         pc->error = IDETAPE_ERROR_EOD;
449                         pc->flags |= PC_FLAG_ABORT;
450                 }
451                 if (!(pc->flags & PC_FLAG_ABORT) &&
452                     pc->xferred)
453                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
454         }
455 }
456
457 /* Free data buffers completely. */
458 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
459 {
460         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
461
462         while (bh) {
463                 u32 size = bh->b_size;
464
465                 while (size) {
466                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
467
468                         if (bh->b_data)
469                                 free_pages((unsigned long)bh->b_data, order);
470
471                         size &= (order-1);
472                         bh->b_data += (1 << order) * PAGE_SIZE;
473                 }
474                 prev_bh = bh;
475                 bh = bh->b_reqnext;
476                 kfree(prev_bh);
477         }
478 }
479
480 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
481 {
482         struct request *rq = HWGROUP(drive)->rq;
483         idetape_tape_t *tape = drive->driver_data;
484         unsigned long flags;
485         int error;
486
487         debug_log(DBG_PROCS, "Enter %s\n", __func__);
488
489         switch (uptodate) {
490         case 0: error = IDETAPE_ERROR_GENERAL; break;
491         case 1: error = 0; break;
492         default: error = uptodate;
493         }
494         rq->errors = error;
495         if (error)
496                 tape->failed_pc = NULL;
497
498         if (!blk_special_request(rq)) {
499                 ide_end_request(drive, uptodate, nr_sects);
500                 return 0;
501         }
502
503         spin_lock_irqsave(&tape->lock, flags);
504
505         ide_end_drive_cmd(drive, 0, 0);
506
507         spin_unlock_irqrestore(&tape->lock, flags);
508         return 0;
509 }
510
511 static void ide_tape_handle_dsc(ide_drive_t *);
512
513 static void ide_tape_callback(ide_drive_t *drive, int dsc)
514 {
515         idetape_tape_t *tape = drive->driver_data;
516         struct ide_atapi_pc *pc = drive->pc;
517         int uptodate = pc->error ? 0 : 1;
518
519         debug_log(DBG_PROCS, "Enter %s\n", __func__);
520
521         if (dsc)
522                 ide_tape_handle_dsc(drive);
523
524         if (tape->failed_pc == pc)
525                 tape->failed_pc = NULL;
526
527         if (pc->c[0] == REQUEST_SENSE) {
528                 if (uptodate)
529                         idetape_analyze_error(drive, pc->buf);
530                 else
531                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
532                                         "itself - Aborting request!\n");
533         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
534                 struct request *rq = drive->hwif->hwgroup->rq;
535                 int blocks = pc->xferred / tape->blk_size;
536
537                 tape->avg_size += blocks * tape->blk_size;
538
539                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
540                         tape->avg_speed = tape->avg_size * HZ /
541                                 (jiffies - tape->avg_time) / 1024;
542                         tape->avg_size = 0;
543                         tape->avg_time = jiffies;
544                 }
545
546                 tape->first_frame += blocks;
547                 rq->current_nr_sectors -= blocks;
548
549                 if (pc->error)
550                         uptodate = pc->error;
551         } else if (pc->c[0] == READ_POSITION && uptodate) {
552                 u8 *readpos = pc->buf;
553
554                 debug_log(DBG_SENSE, "BOP - %s\n",
555                                 (readpos[0] & 0x80) ? "Yes" : "No");
556                 debug_log(DBG_SENSE, "EOP - %s\n",
557                                 (readpos[0] & 0x40) ? "Yes" : "No");
558
559                 if (readpos[0] & 0x4) {
560                         printk(KERN_INFO "ide-tape: Block location is unknown"
561                                          "to the tape\n");
562                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
563                         uptodate = 0;
564                 } else {
565                         debug_log(DBG_SENSE, "Block Location - %u\n",
566                                         be32_to_cpup((__be32 *)&readpos[4]));
567
568                         tape->partition = readpos[1];
569                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
570                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
571                 }
572         }
573
574         idetape_end_request(drive, uptodate, 0);
575 }
576
577 /*
578  * Postpone the current request so that ide.c will be able to service requests
579  * from another device on the same hwgroup while we are polling for DSC.
580  */
581 static void idetape_postpone_request(ide_drive_t *drive)
582 {
583         idetape_tape_t *tape = drive->driver_data;
584
585         debug_log(DBG_PROCS, "Enter %s\n", __func__);
586
587         tape->postponed_rq = HWGROUP(drive)->rq;
588         ide_stall_queue(drive, tape->dsc_poll_freq);
589 }
590
591 static void ide_tape_handle_dsc(ide_drive_t *drive)
592 {
593         idetape_tape_t *tape = drive->driver_data;
594
595         /* Media access command */
596         tape->dsc_polling_start = jiffies;
597         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
598         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
599         /* Allow ide.c to handle other requests */
600         idetape_postpone_request(drive);
601 }
602
603 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
604                                 unsigned int bcount, int write)
605 {
606         if (write)
607                 idetape_output_buffers(drive, pc, bcount);
608         else
609                 idetape_input_buffers(drive, pc, bcount);
610
611         return bcount;
612 }
613
614 /*
615  * Packet Command Interface
616  *
617  * The current Packet Command is available in drive->pc, and will not change
618  * until we finish handling it. Each packet command is associated with a
619  * callback function that will be called when the command is finished.
620  *
621  * The handling will be done in three stages:
622  *
623  * 1. idetape_issue_pc will send the packet command to the drive, and will set
624  * the interrupt handler to ide_pc_intr.
625  *
626  * 2. On each interrupt, ide_pc_intr will be called. This step will be
627  * repeated until the device signals us that no more interrupts will be issued.
628  *
629  * 3. ATAPI Tape media access commands have immediate status with a delayed
630  * process. In case of a successful initiation of a media access packet command,
631  * the DSC bit will be set when the actual execution of the command is finished.
632  * Since the tape drive will not issue an interrupt, we have to poll for this
633  * event. In this case, we define the request as "low priority request" by
634  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
635  * exit the driver.
636  *
637  * ide.c will then give higher priority to requests which originate from the
638  * other device, until will change rq_status to RQ_ACTIVE.
639  *
640  * 4. When the packet command is finished, it will be checked for errors.
641  *
642  * 5. In case an error was found, we queue a request sense packet command in
643  * front of the request queue and retry the operation up to
644  * IDETAPE_MAX_PC_RETRIES times.
645  *
646  * 6. In case no error was found, or we decided to give up and not to retry
647  * again, the callback function will be called and then we will handle the next
648  * request.
649  */
650
651 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
652                 struct ide_atapi_pc *pc)
653 {
654         idetape_tape_t *tape = drive->driver_data;
655
656         if (drive->pc->c[0] == REQUEST_SENSE &&
657             pc->c[0] == REQUEST_SENSE) {
658                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
659                         "Two request sense in serial were issued\n");
660         }
661
662         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
663                 tape->failed_pc = pc;
664
665         /* Set the current packet command */
666         drive->pc = pc;
667
668         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
669                 (pc->flags & PC_FLAG_ABORT)) {
670                 /*
671                  * We will "abort" retrying a packet command in case legitimate
672                  * error code was received (crossing a filemark, or end of the
673                  * media, for example).
674                  */
675                 if (!(pc->flags & PC_FLAG_ABORT)) {
676                         if (!(pc->c[0] == TEST_UNIT_READY &&
677                               tape->sense_key == 2 && tape->asc == 4 &&
678                              (tape->ascq == 1 || tape->ascq == 8))) {
679                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
680                                                 "pc = %2x, key = %2x, "
681                                                 "asc = %2x, ascq = %2x\n",
682                                                 tape->name, pc->c[0],
683                                                 tape->sense_key, tape->asc,
684                                                 tape->ascq);
685                         }
686                         /* Giving up */
687                         pc->error = IDETAPE_ERROR_GENERAL;
688                 }
689                 tape->failed_pc = NULL;
690                 drive->pc_callback(drive, 0);
691                 return ide_stopped;
692         }
693         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
694
695         pc->retries++;
696
697         return ide_issue_pc(drive);
698 }
699
700 /* A mode sense command is used to "sense" tape parameters. */
701 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
702 {
703         ide_init_pc(pc);
704         pc->c[0] = MODE_SENSE;
705         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
706                 /* DBD = 1 - Don't return block descriptors */
707                 pc->c[1] = 8;
708         pc->c[2] = page_code;
709         /*
710          * Changed pc->c[3] to 0 (255 will at best return unused info).
711          *
712          * For SCSI this byte is defined as subpage instead of high byte
713          * of length and some IDE drives seem to interpret it this way
714          * and return an error when 255 is used.
715          */
716         pc->c[3] = 0;
717         /* We will just discard data in that case */
718         pc->c[4] = 255;
719         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
720                 pc->req_xfer = 12;
721         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
722                 pc->req_xfer = 24;
723         else
724                 pc->req_xfer = 50;
725 }
726
727 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
728 {
729         ide_hwif_t *hwif = drive->hwif;
730         idetape_tape_t *tape = drive->driver_data;
731         struct ide_atapi_pc *pc = drive->pc;
732         u8 stat;
733
734         stat = hwif->tp_ops->read_status(hwif);
735
736         if (stat & ATA_DSC) {
737                 if (stat & ATA_ERR) {
738                         /* Error detected */
739                         if (pc->c[0] != TEST_UNIT_READY)
740                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
741                                                 tape->name);
742                         /* Retry operation */
743                         ide_retry_pc(drive, tape->disk);
744                         return ide_stopped;
745                 }
746                 pc->error = 0;
747         } else {
748                 pc->error = IDETAPE_ERROR_GENERAL;
749                 tape->failed_pc = NULL;
750         }
751         drive->pc_callback(drive, 0);
752         return ide_stopped;
753 }
754
755 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
756                                    struct ide_atapi_pc *pc, struct request *rq,
757                                    u8 opcode)
758 {
759         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
760         unsigned int length = rq->current_nr_sectors;
761
762         ide_init_pc(pc);
763         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
764         pc->c[1] = 1;
765         pc->bh = bh;
766         pc->buf = NULL;
767         pc->buf_size = length * tape->blk_size;
768         pc->req_xfer = pc->buf_size;
769         if (pc->req_xfer == tape->buffer_size)
770                 pc->flags |= PC_FLAG_DMA_OK;
771
772         if (opcode == READ_6) {
773                 pc->c[0] = READ_6;
774                 atomic_set(&bh->b_count, 0);
775         } else if (opcode == WRITE_6) {
776                 pc->c[0] = WRITE_6;
777                 pc->flags |= PC_FLAG_WRITING;
778                 pc->b_data = bh->b_data;
779                 pc->b_count = atomic_read(&bh->b_count);
780         }
781
782         memcpy(rq->cmd, pc->c, 12);
783 }
784
785 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
786                                           struct request *rq, sector_t block)
787 {
788         ide_hwif_t *hwif = drive->hwif;
789         idetape_tape_t *tape = drive->driver_data;
790         struct ide_atapi_pc *pc = NULL;
791         struct request *postponed_rq = tape->postponed_rq;
792         u8 stat;
793
794         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
795                         " current_nr_sectors: %u\n",
796                         (unsigned long long)rq->sector, rq->nr_sectors,
797                         rq->current_nr_sectors);
798
799         if (!blk_special_request(rq)) {
800                 /* We do not support buffer cache originated requests. */
801                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
802                         "request queue (%d)\n", drive->name, rq->cmd_type);
803                 ide_end_request(drive, 0, 0);
804                 return ide_stopped;
805         }
806
807         /* Retry a failed packet command */
808         if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
809                 pc = tape->failed_pc;
810                 goto out;
811         }
812
813         if (postponed_rq != NULL)
814                 if (rq != postponed_rq) {
815                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
816                                         "Two DSC requests were queued\n");
817                         idetape_end_request(drive, 0, 0);
818                         return ide_stopped;
819                 }
820
821         tape->postponed_rq = NULL;
822
823         /*
824          * If the tape is still busy, postpone our request and service
825          * the other device meanwhile.
826          */
827         stat = hwif->tp_ops->read_status(hwif);
828
829         if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
830             (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
831                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
832
833         if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
834                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
835                 drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
836         }
837
838         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
839             (stat & ATA_DSC) == 0) {
840                 if (postponed_rq == NULL) {
841                         tape->dsc_polling_start = jiffies;
842                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
843                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
844                 } else if (time_after(jiffies, tape->dsc_timeout)) {
845                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
846                                 tape->name);
847                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
848                                 idetape_media_access_finished(drive);
849                                 return ide_stopped;
850                         } else {
851                                 return ide_do_reset(drive);
852                         }
853                 } else if (time_after(jiffies,
854                                         tape->dsc_polling_start +
855                                         IDETAPE_DSC_MA_THRESHOLD))
856                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
857                 idetape_postpone_request(drive);
858                 return ide_stopped;
859         }
860         if (rq->cmd[13] & REQ_IDETAPE_READ) {
861                 pc = &tape->queued_pc;
862                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
863                 goto out;
864         }
865         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
866                 pc = &tape->queued_pc;
867                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
868                 goto out;
869         }
870         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
871                 pc = (struct ide_atapi_pc *) rq->buffer;
872                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
873                 rq->cmd[13] |= REQ_IDETAPE_PC2;
874                 goto out;
875         }
876         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
877                 idetape_media_access_finished(drive);
878                 return ide_stopped;
879         }
880         BUG();
881
882 out:
883         return idetape_issue_pc(drive, pc);
884 }
885
886 /*
887  * The function below uses __get_free_pages to allocate a data buffer of size
888  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
889  * much as possible.
890  *
891  * It returns a pointer to the newly allocated buffer, or NULL in case of
892  * failure.
893  */
894 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
895                                                   int full, int clear)
896 {
897         struct idetape_bh *prev_bh, *bh, *merge_bh;
898         int pages = tape->pages_per_buffer;
899         unsigned int order, b_allocd;
900         char *b_data = NULL;
901
902         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
903         bh = merge_bh;
904         if (bh == NULL)
905                 goto abort;
906
907         order = fls(pages) - 1;
908         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
909         if (!bh->b_data)
910                 goto abort;
911         b_allocd = (1 << order) * PAGE_SIZE;
912         pages &= (order-1);
913
914         if (clear)
915                 memset(bh->b_data, 0, b_allocd);
916         bh->b_reqnext = NULL;
917         bh->b_size = b_allocd;
918         atomic_set(&bh->b_count, full ? bh->b_size : 0);
919
920         while (pages) {
921                 order = fls(pages) - 1;
922                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
923                 if (!b_data)
924                         goto abort;
925                 b_allocd = (1 << order) * PAGE_SIZE;
926
927                 if (clear)
928                         memset(b_data, 0, b_allocd);
929
930                 /* newly allocated page frames below buffer header or ...*/
931                 if (bh->b_data == b_data + b_allocd) {
932                         bh->b_size += b_allocd;
933                         bh->b_data -= b_allocd;
934                         if (full)
935                                 atomic_add(b_allocd, &bh->b_count);
936                         continue;
937                 }
938                 /* they are above the header */
939                 if (b_data == bh->b_data + bh->b_size) {
940                         bh->b_size += b_allocd;
941                         if (full)
942                                 atomic_add(b_allocd, &bh->b_count);
943                         continue;
944                 }
945                 prev_bh = bh;
946                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
947                 if (!bh) {
948                         free_pages((unsigned long) b_data, order);
949                         goto abort;
950                 }
951                 bh->b_reqnext = NULL;
952                 bh->b_data = b_data;
953                 bh->b_size = b_allocd;
954                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
955                 prev_bh->b_reqnext = bh;
956
957                 pages &= (order-1);
958         }
959
960         bh->b_size -= tape->excess_bh_size;
961         if (full)
962                 atomic_sub(tape->excess_bh_size, &bh->b_count);
963         return merge_bh;
964 abort:
965         ide_tape_kfree_buffer(tape);
966         return NULL;
967 }
968
969 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
970                                         const char __user *buf, int n)
971 {
972         struct idetape_bh *bh = tape->bh;
973         int count;
974         int ret = 0;
975
976         while (n) {
977                 if (bh == NULL) {
978                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
979                                         __func__);
980                         return 1;
981                 }
982                 count = min((unsigned int)
983                                 (bh->b_size - atomic_read(&bh->b_count)),
984                                 (unsigned int)n);
985                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
986                                 count))
987                         ret = 1;
988                 n -= count;
989                 atomic_add(count, &bh->b_count);
990                 buf += count;
991                 if (atomic_read(&bh->b_count) == bh->b_size) {
992                         bh = bh->b_reqnext;
993                         if (bh)
994                                 atomic_set(&bh->b_count, 0);
995                 }
996         }
997         tape->bh = bh;
998         return ret;
999 }
1000
1001 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1002                                       int n)
1003 {
1004         struct idetape_bh *bh = tape->bh;
1005         int count;
1006         int ret = 0;
1007
1008         while (n) {
1009                 if (bh == NULL) {
1010                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1011                                         __func__);
1012                         return 1;
1013                 }
1014                 count = min(tape->b_count, n);
1015                 if  (copy_to_user(buf, tape->b_data, count))
1016                         ret = 1;
1017                 n -= count;
1018                 tape->b_data += count;
1019                 tape->b_count -= count;
1020                 buf += count;
1021                 if (!tape->b_count) {
1022                         bh = bh->b_reqnext;
1023                         tape->bh = bh;
1024                         if (bh) {
1025                                 tape->b_data = bh->b_data;
1026                                 tape->b_count = atomic_read(&bh->b_count);
1027                         }
1028                 }
1029         }
1030         return ret;
1031 }
1032
1033 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1034 {
1035         struct idetape_bh *bh = tape->merge_bh;
1036         tape->bh = tape->merge_bh;
1037
1038         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1039                 atomic_set(&bh->b_count, 0);
1040         else {
1041                 tape->b_data = bh->b_data;
1042                 tape->b_count = atomic_read(&bh->b_count);
1043         }
1044 }
1045
1046 /*
1047  * Write a filemark if write_filemark=1. Flush the device buffers without
1048  * writing a filemark otherwise.
1049  */
1050 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1051                 struct ide_atapi_pc *pc, int write_filemark)
1052 {
1053         ide_init_pc(pc);
1054         pc->c[0] = WRITE_FILEMARKS;
1055         pc->c[4] = write_filemark;
1056         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1057 }
1058
1059 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1060 {
1061         idetape_tape_t *tape = drive->driver_data;
1062         struct gendisk *disk = tape->disk;
1063         int load_attempted = 0;
1064
1065         /* Wait for the tape to become ready */
1066         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1067         timeout += jiffies;
1068         while (time_before(jiffies, timeout)) {
1069                 if (ide_do_test_unit_ready(drive, disk) == 0)
1070                         return 0;
1071                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1072                     || (tape->asc == 0x3A)) {
1073                         /* no media */
1074                         if (load_attempted)
1075                                 return -ENOMEDIUM;
1076                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1077                         load_attempted = 1;
1078                 /* not about to be ready */
1079                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1080                              (tape->ascq == 1 || tape->ascq == 8)))
1081                         return -EIO;
1082                 msleep(100);
1083         }
1084         return -EIO;
1085 }
1086
1087 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1088 {
1089         struct ide_tape_obj *tape = drive->driver_data;
1090         struct ide_atapi_pc pc;
1091         int rc;
1092
1093         idetape_create_write_filemark_cmd(drive, &pc, 0);
1094         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1095         if (rc)
1096                 return rc;
1097         idetape_wait_ready(drive, 60 * 5 * HZ);
1098         return 0;
1099 }
1100
1101 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1102 {
1103         ide_init_pc(pc);
1104         pc->c[0] = READ_POSITION;
1105         pc->req_xfer = 20;
1106 }
1107
1108 static int idetape_read_position(ide_drive_t *drive)
1109 {
1110         idetape_tape_t *tape = drive->driver_data;
1111         struct ide_atapi_pc pc;
1112         int position;
1113
1114         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1115
1116         idetape_create_read_position_cmd(&pc);
1117         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1118                 return -1;
1119         position = tape->first_frame;
1120         return position;
1121 }
1122
1123 static void idetape_create_locate_cmd(ide_drive_t *drive,
1124                 struct ide_atapi_pc *pc,
1125                 unsigned int block, u8 partition, int skip)
1126 {
1127         ide_init_pc(pc);
1128         pc->c[0] = POSITION_TO_ELEMENT;
1129         pc->c[1] = 2;
1130         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1131         pc->c[8] = partition;
1132         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1133 }
1134
1135 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1136 {
1137         idetape_tape_t *tape = drive->driver_data;
1138
1139         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1140                 return;
1141
1142         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1143         tape->merge_bh_size = 0;
1144         if (tape->merge_bh != NULL) {
1145                 ide_tape_kfree_buffer(tape);
1146                 tape->merge_bh = NULL;
1147         }
1148
1149         tape->chrdev_dir = IDETAPE_DIR_NONE;
1150 }
1151
1152 /*
1153  * Position the tape to the requested block using the LOCATE packet command.
1154  * A READ POSITION command is then issued to check where we are positioned. Like
1155  * all higher level operations, we queue the commands at the tail of the request
1156  * queue and wait for their completion.
1157  */
1158 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1159                 u8 partition, int skip)
1160 {
1161         idetape_tape_t *tape = drive->driver_data;
1162         struct gendisk *disk = tape->disk;
1163         int retval;
1164         struct ide_atapi_pc pc;
1165
1166         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1167                 __ide_tape_discard_merge_buffer(drive);
1168         idetape_wait_ready(drive, 60 * 5 * HZ);
1169         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1170         retval = ide_queue_pc_tail(drive, disk, &pc);
1171         if (retval)
1172                 return (retval);
1173
1174         idetape_create_read_position_cmd(&pc);
1175         return ide_queue_pc_tail(drive, disk, &pc);
1176 }
1177
1178 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1179                                           int restore_position)
1180 {
1181         idetape_tape_t *tape = drive->driver_data;
1182         int seek, position;
1183
1184         __ide_tape_discard_merge_buffer(drive);
1185         if (restore_position) {
1186                 position = idetape_read_position(drive);
1187                 seek = position > 0 ? position : 0;
1188                 if (idetape_position_tape(drive, seek, 0, 0)) {
1189                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1190                                          " %s\n", tape->name, __func__);
1191                         return;
1192                 }
1193         }
1194 }
1195
1196 /*
1197  * Generate a read/write request for the block device interface and wait for it
1198  * to be serviced.
1199  */
1200 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1201                                  struct idetape_bh *bh)
1202 {
1203         idetape_tape_t *tape = drive->driver_data;
1204         struct request *rq;
1205         int ret, errors;
1206
1207         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1208
1209         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1210         rq->cmd_type = REQ_TYPE_SPECIAL;
1211         rq->cmd[13] = cmd;
1212         rq->rq_disk = tape->disk;
1213         rq->special = (void *)bh;
1214         rq->sector = tape->first_frame;
1215         rq->nr_sectors = blocks;
1216         rq->current_nr_sectors = blocks;
1217         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1218
1219         errors = rq->errors;
1220         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1221         blk_put_request(rq);
1222
1223         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1224                 return 0;
1225
1226         if (tape->merge_bh)
1227                 idetape_init_merge_buffer(tape);
1228         if (errors == IDETAPE_ERROR_GENERAL)
1229                 return -EIO;
1230         return ret;
1231 }
1232
1233 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1234 {
1235         ide_init_pc(pc);
1236         pc->c[0] = INQUIRY;
1237         pc->c[4] = 254;
1238         pc->req_xfer = 254;
1239 }
1240
1241 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1242                 struct ide_atapi_pc *pc)
1243 {
1244         ide_init_pc(pc);
1245         pc->c[0] = REZERO_UNIT;
1246         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1247 }
1248
1249 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1250 {
1251         ide_init_pc(pc);
1252         pc->c[0] = ERASE;
1253         pc->c[1] = 1;
1254         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1255 }
1256
1257 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1258 {
1259         ide_init_pc(pc);
1260         pc->c[0] = SPACE;
1261         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1262         pc->c[1] = cmd;
1263         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1264 }
1265
1266 /* Queue up a character device originated write request. */
1267 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1268 {
1269         idetape_tape_t *tape = drive->driver_data;
1270
1271         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1272
1273         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1274                                      blocks, tape->merge_bh);
1275 }
1276
1277 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1278 {
1279         idetape_tape_t *tape = drive->driver_data;
1280         int blocks, min;
1281         struct idetape_bh *bh;
1282
1283         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1284                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1285                                 " but we are not writing.\n");
1286                 return;
1287         }
1288         if (tape->merge_bh_size > tape->buffer_size) {
1289                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1290                 tape->merge_bh_size = tape->buffer_size;
1291         }
1292         if (tape->merge_bh_size) {
1293                 blocks = tape->merge_bh_size / tape->blk_size;
1294                 if (tape->merge_bh_size % tape->blk_size) {
1295                         unsigned int i;
1296
1297                         blocks++;
1298                         i = tape->blk_size - tape->merge_bh_size %
1299                                 tape->blk_size;
1300                         bh = tape->bh->b_reqnext;
1301                         while (bh) {
1302                                 atomic_set(&bh->b_count, 0);
1303                                 bh = bh->b_reqnext;
1304                         }
1305                         bh = tape->bh;
1306                         while (i) {
1307                                 if (bh == NULL) {
1308                                         printk(KERN_INFO "ide-tape: bug,"
1309                                                          " bh NULL\n");
1310                                         break;
1311                                 }
1312                                 min = min(i, (unsigned int)(bh->b_size -
1313                                                 atomic_read(&bh->b_count)));
1314                                 memset(bh->b_data + atomic_read(&bh->b_count),
1315                                                 0, min);
1316                                 atomic_add(min, &bh->b_count);
1317                                 i -= min;
1318                                 bh = bh->b_reqnext;
1319                         }
1320                 }
1321                 (void) idetape_add_chrdev_write_request(drive, blocks);
1322                 tape->merge_bh_size = 0;
1323         }
1324         if (tape->merge_bh != NULL) {
1325                 ide_tape_kfree_buffer(tape);
1326                 tape->merge_bh = NULL;
1327         }
1328         tape->chrdev_dir = IDETAPE_DIR_NONE;
1329 }
1330
1331 static int idetape_init_read(ide_drive_t *drive)
1332 {
1333         idetape_tape_t *tape = drive->driver_data;
1334         int bytes_read;
1335
1336         /* Initialize read operation */
1337         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1338                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1339                         ide_tape_flush_merge_buffer(drive);
1340                         idetape_flush_tape_buffers(drive);
1341                 }
1342                 if (tape->merge_bh || tape->merge_bh_size) {
1343                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1344                                          " 0 now\n");
1345                         tape->merge_bh_size = 0;
1346                 }
1347                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1348                 if (!tape->merge_bh)
1349                         return -ENOMEM;
1350                 tape->chrdev_dir = IDETAPE_DIR_READ;
1351
1352                 /*
1353                  * Issue a read 0 command to ensure that DSC handshake is
1354                  * switched from completion mode to buffer available mode.
1355                  * No point in issuing this if DSC overlap isn't supported, some
1356                  * drives (Seagate STT3401A) will return an error.
1357                  */
1358                 if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
1359                         bytes_read = idetape_queue_rw_tail(drive,
1360                                                         REQ_IDETAPE_READ, 0,
1361                                                         tape->merge_bh);
1362                         if (bytes_read < 0) {
1363                                 ide_tape_kfree_buffer(tape);
1364                                 tape->merge_bh = NULL;
1365                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1366                                 return bytes_read;
1367                         }
1368                 }
1369         }
1370
1371         return 0;
1372 }
1373
1374 /* called from idetape_chrdev_read() to service a chrdev read request. */
1375 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1376 {
1377         idetape_tape_t *tape = drive->driver_data;
1378
1379         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1380
1381         /* If we are at a filemark, return a read length of 0 */
1382         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1383                 return 0;
1384
1385         idetape_init_read(drive);
1386
1387         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1388                                      tape->merge_bh);
1389 }
1390
1391 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1392 {
1393         idetape_tape_t *tape = drive->driver_data;
1394         struct idetape_bh *bh;
1395         int blocks;
1396
1397         while (bcount) {
1398                 unsigned int count;
1399
1400                 bh = tape->merge_bh;
1401                 count = min(tape->buffer_size, bcount);
1402                 bcount -= count;
1403                 blocks = count / tape->blk_size;
1404                 while (count) {
1405                         atomic_set(&bh->b_count,
1406                                    min(count, (unsigned int)bh->b_size));
1407                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1408                         count -= atomic_read(&bh->b_count);
1409                         bh = bh->b_reqnext;
1410                 }
1411                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1412                                       tape->merge_bh);
1413         }
1414 }
1415
1416 /*
1417  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1418  * currently support only one partition.
1419  */
1420 static int idetape_rewind_tape(ide_drive_t *drive)
1421 {
1422         struct ide_tape_obj *tape = drive->driver_data;
1423         struct gendisk *disk = tape->disk;
1424         int retval;
1425         struct ide_atapi_pc pc;
1426
1427         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1428
1429         idetape_create_rewind_cmd(drive, &pc);
1430         retval = ide_queue_pc_tail(drive, disk, &pc);
1431         if (retval)
1432                 return retval;
1433
1434         idetape_create_read_position_cmd(&pc);
1435         retval = ide_queue_pc_tail(drive, disk, &pc);
1436         if (retval)
1437                 return retval;
1438         return 0;
1439 }
1440
1441 /* mtio.h compatible commands should be issued to the chrdev interface. */
1442 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1443                                 unsigned long arg)
1444 {
1445         idetape_tape_t *tape = drive->driver_data;
1446         void __user *argp = (void __user *)arg;
1447
1448         struct idetape_config {
1449                 int dsc_rw_frequency;
1450                 int dsc_media_access_frequency;
1451                 int nr_stages;
1452         } config;
1453
1454         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1455
1456         switch (cmd) {
1457         case 0x0340:
1458                 if (copy_from_user(&config, argp, sizeof(config)))
1459                         return -EFAULT;
1460                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1461                 break;
1462         case 0x0350:
1463                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1464                 config.nr_stages = 1;
1465                 if (copy_to_user(argp, &config, sizeof(config)))
1466                         return -EFAULT;
1467                 break;
1468         default:
1469                 return -EIO;
1470         }
1471         return 0;
1472 }
1473
1474 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1475                                         int mt_count)
1476 {
1477         idetape_tape_t *tape = drive->driver_data;
1478         struct gendisk *disk = tape->disk;
1479         struct ide_atapi_pc pc;
1480         int retval, count = 0;
1481         int sprev = !!(tape->caps[4] & 0x20);
1482
1483         if (mt_count == 0)
1484                 return 0;
1485         if (MTBSF == mt_op || MTBSFM == mt_op) {
1486                 if (!sprev)
1487                         return -EIO;
1488                 mt_count = -mt_count;
1489         }
1490
1491         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1492                 tape->merge_bh_size = 0;
1493                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1494                         ++count;
1495                 ide_tape_discard_merge_buffer(drive, 0);
1496         }
1497
1498         switch (mt_op) {
1499         case MTFSF:
1500         case MTBSF:
1501                 idetape_create_space_cmd(&pc, mt_count - count,
1502                                          IDETAPE_SPACE_OVER_FILEMARK);
1503                 return ide_queue_pc_tail(drive, disk, &pc);
1504         case MTFSFM:
1505         case MTBSFM:
1506                 if (!sprev)
1507                         return -EIO;
1508                 retval = idetape_space_over_filemarks(drive, MTFSF,
1509                                                       mt_count - count);
1510                 if (retval)
1511                         return retval;
1512                 count = (MTBSFM == mt_op ? 1 : -1);
1513                 return idetape_space_over_filemarks(drive, MTFSF, count);
1514         default:
1515                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1516                                 mt_op);
1517                 return -EIO;
1518         }
1519 }
1520
1521 /*
1522  * Our character device read / write functions.
1523  *
1524  * The tape is optimized to maximize throughput when it is transferring an
1525  * integral number of the "continuous transfer limit", which is a parameter of
1526  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1527  *
1528  * As of version 1.3 of the driver, the character device provides an abstract
1529  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1530  * same backup/restore procedure is supported. The driver will internally
1531  * convert the requests to the recommended transfer unit, so that an unmatch
1532  * between the user's block size to the recommended size will only result in a
1533  * (slightly) increased driver overhead, but will no longer hit performance.
1534  * This is not applicable to Onstream.
1535  */
1536 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1537                                    size_t count, loff_t *ppos)
1538 {
1539         struct ide_tape_obj *tape = file->private_data;
1540         ide_drive_t *drive = tape->drive;
1541         ssize_t bytes_read, temp, actually_read = 0, rc;
1542         ssize_t ret = 0;
1543         u16 ctl = *(u16 *)&tape->caps[12];
1544
1545         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1546
1547         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1548                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1549                         if (count > tape->blk_size &&
1550                             (count % tape->blk_size) == 0)
1551                                 tape->user_bs_factor = count / tape->blk_size;
1552         }
1553         rc = idetape_init_read(drive);
1554         if (rc < 0)
1555                 return rc;
1556         if (count == 0)
1557                 return (0);
1558         if (tape->merge_bh_size) {
1559                 actually_read = min((unsigned int)(tape->merge_bh_size),
1560                                     (unsigned int)count);
1561                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1562                         ret = -EFAULT;
1563                 buf += actually_read;
1564                 tape->merge_bh_size -= actually_read;
1565                 count -= actually_read;
1566         }
1567         while (count >= tape->buffer_size) {
1568                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1569                 if (bytes_read <= 0)
1570                         goto finish;
1571                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1572                         ret = -EFAULT;
1573                 buf += bytes_read;
1574                 count -= bytes_read;
1575                 actually_read += bytes_read;
1576         }
1577         if (count) {
1578                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1579                 if (bytes_read <= 0)
1580                         goto finish;
1581                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1582                 if (idetape_copy_stage_to_user(tape, buf, temp))
1583                         ret = -EFAULT;
1584                 actually_read += temp;
1585                 tape->merge_bh_size = bytes_read-temp;
1586         }
1587 finish:
1588         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1589                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1590
1591                 idetape_space_over_filemarks(drive, MTFSF, 1);
1592                 return 0;
1593         }
1594
1595         return ret ? ret : actually_read;
1596 }
1597
1598 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1599                                      size_t count, loff_t *ppos)
1600 {
1601         struct ide_tape_obj *tape = file->private_data;
1602         ide_drive_t *drive = tape->drive;
1603         ssize_t actually_written = 0;
1604         ssize_t ret = 0;
1605         u16 ctl = *(u16 *)&tape->caps[12];
1606
1607         /* The drive is write protected. */
1608         if (tape->write_prot)
1609                 return -EACCES;
1610
1611         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1612
1613         /* Initialize write operation */
1614         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1615                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1616                         ide_tape_discard_merge_buffer(drive, 1);
1617                 if (tape->merge_bh || tape->merge_bh_size) {
1618                         printk(KERN_ERR "ide-tape: merge_bh_size "
1619                                 "should be 0 now\n");
1620                         tape->merge_bh_size = 0;
1621                 }
1622                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1623                 if (!tape->merge_bh)
1624                         return -ENOMEM;
1625                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1626                 idetape_init_merge_buffer(tape);
1627
1628                 /*
1629                  * Issue a write 0 command to ensure that DSC handshake is
1630                  * switched from completion mode to buffer available mode. No
1631                  * point in issuing this if DSC overlap isn't supported, some
1632                  * drives (Seagate STT3401A) will return an error.
1633                  */
1634                 if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
1635                         ssize_t retval = idetape_queue_rw_tail(drive,
1636                                                         REQ_IDETAPE_WRITE, 0,
1637                                                         tape->merge_bh);
1638                         if (retval < 0) {
1639                                 ide_tape_kfree_buffer(tape);
1640                                 tape->merge_bh = NULL;
1641                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1642                                 return retval;
1643                         }
1644                 }
1645         }
1646         if (count == 0)
1647                 return (0);
1648         if (tape->merge_bh_size) {
1649                 if (tape->merge_bh_size >= tape->buffer_size) {
1650                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1651                         tape->merge_bh_size = 0;
1652                 }
1653                 actually_written = min((unsigned int)
1654                                 (tape->buffer_size - tape->merge_bh_size),
1655                                 (unsigned int)count);
1656                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1657                                 ret = -EFAULT;
1658                 buf += actually_written;
1659                 tape->merge_bh_size += actually_written;
1660                 count -= actually_written;
1661
1662                 if (tape->merge_bh_size == tape->buffer_size) {
1663                         ssize_t retval;
1664                         tape->merge_bh_size = 0;
1665                         retval = idetape_add_chrdev_write_request(drive, ctl);
1666                         if (retval <= 0)
1667                                 return (retval);
1668                 }
1669         }
1670         while (count >= tape->buffer_size) {
1671                 ssize_t retval;
1672                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1673                         ret = -EFAULT;
1674                 buf += tape->buffer_size;
1675                 count -= tape->buffer_size;
1676                 retval = idetape_add_chrdev_write_request(drive, ctl);
1677                 actually_written += tape->buffer_size;
1678                 if (retval <= 0)
1679                         return (retval);
1680         }
1681         if (count) {
1682                 actually_written += count;
1683                 if (idetape_copy_stage_from_user(tape, buf, count))
1684                         ret = -EFAULT;
1685                 tape->merge_bh_size += count;
1686         }
1687         return ret ? ret : actually_written;
1688 }
1689
1690 static int idetape_write_filemark(ide_drive_t *drive)
1691 {
1692         struct ide_tape_obj *tape = drive->driver_data;
1693         struct ide_atapi_pc pc;
1694
1695         /* Write a filemark */
1696         idetape_create_write_filemark_cmd(drive, &pc, 1);
1697         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1698                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1699                 return -EIO;
1700         }
1701         return 0;
1702 }
1703
1704 /*
1705  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1706  * requested.
1707  *
1708  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1709  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1710  * usually not supported.
1711  *
1712  * The following commands are currently not supported:
1713  *
1714  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1715  * MT_ST_WRITE_THRESHOLD.
1716  */
1717 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1718 {
1719         idetape_tape_t *tape = drive->driver_data;
1720         struct gendisk *disk = tape->disk;
1721         struct ide_atapi_pc pc;
1722         int i, retval;
1723
1724         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1725                         mt_op, mt_count);
1726
1727         switch (mt_op) {
1728         case MTFSF:
1729         case MTFSFM:
1730         case MTBSF:
1731         case MTBSFM:
1732                 if (!mt_count)
1733                         return 0;
1734                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1735         default:
1736                 break;
1737         }
1738
1739         switch (mt_op) {
1740         case MTWEOF:
1741                 if (tape->write_prot)
1742                         return -EACCES;
1743                 ide_tape_discard_merge_buffer(drive, 1);
1744                 for (i = 0; i < mt_count; i++) {
1745                         retval = idetape_write_filemark(drive);
1746                         if (retval)
1747                                 return retval;
1748                 }
1749                 return 0;
1750         case MTREW:
1751                 ide_tape_discard_merge_buffer(drive, 0);
1752                 if (idetape_rewind_tape(drive))
1753                         return -EIO;
1754                 return 0;
1755         case MTLOAD:
1756                 ide_tape_discard_merge_buffer(drive, 0);
1757                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1758         case MTUNLOAD:
1759         case MTOFFL:
1760                 /*
1761                  * If door is locked, attempt to unlock before
1762                  * attempting to eject.
1763                  */
1764                 if (tape->door_locked) {
1765                         if (!ide_set_media_lock(drive, disk, 0))
1766                                 tape->door_locked = DOOR_UNLOCKED;
1767                 }
1768                 ide_tape_discard_merge_buffer(drive, 0);
1769                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1770                 if (!retval)
1771                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1772                 return retval;
1773         case MTNOP:
1774                 ide_tape_discard_merge_buffer(drive, 0);
1775                 return idetape_flush_tape_buffers(drive);
1776         case MTRETEN:
1777                 ide_tape_discard_merge_buffer(drive, 0);
1778                 return ide_do_start_stop(drive, disk,
1779                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1780         case MTEOM:
1781                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1782                 return ide_queue_pc_tail(drive, disk, &pc);
1783         case MTERASE:
1784                 (void)idetape_rewind_tape(drive);
1785                 idetape_create_erase_cmd(&pc);
1786                 return ide_queue_pc_tail(drive, disk, &pc);
1787         case MTSETBLK:
1788                 if (mt_count) {
1789                         if (mt_count < tape->blk_size ||
1790                             mt_count % tape->blk_size)
1791                                 return -EIO;
1792                         tape->user_bs_factor = mt_count / tape->blk_size;
1793                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1794                 } else
1795                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1796                 return 0;
1797         case MTSEEK:
1798                 ide_tape_discard_merge_buffer(drive, 0);
1799                 return idetape_position_tape(drive,
1800                         mt_count * tape->user_bs_factor, tape->partition, 0);
1801         case MTSETPART:
1802                 ide_tape_discard_merge_buffer(drive, 0);
1803                 return idetape_position_tape(drive, 0, mt_count, 0);
1804         case MTFSR:
1805         case MTBSR:
1806         case MTLOCK:
1807                 retval = ide_set_media_lock(drive, disk, 1);
1808                 if (retval)
1809                         return retval;
1810                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1811                 return 0;
1812         case MTUNLOCK:
1813                 retval = ide_set_media_lock(drive, disk, 0);
1814                 if (retval)
1815                         return retval;
1816                 tape->door_locked = DOOR_UNLOCKED;
1817                 return 0;
1818         default:
1819                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1820                                 mt_op);
1821                 return -EIO;
1822         }
1823 }
1824
1825 /*
1826  * Our character device ioctls. General mtio.h magnetic io commands are
1827  * supported here, and not in the corresponding block interface. Our own
1828  * ide-tape ioctls are supported on both interfaces.
1829  */
1830 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1831                                 unsigned int cmd, unsigned long arg)
1832 {
1833         struct ide_tape_obj *tape = file->private_data;
1834         ide_drive_t *drive = tape->drive;
1835         struct mtop mtop;
1836         struct mtget mtget;
1837         struct mtpos mtpos;
1838         int block_offset = 0, position = tape->first_frame;
1839         void __user *argp = (void __user *)arg;
1840
1841         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1842
1843         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1844                 ide_tape_flush_merge_buffer(drive);
1845                 idetape_flush_tape_buffers(drive);
1846         }
1847         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1848                 block_offset = tape->merge_bh_size /
1849                         (tape->blk_size * tape->user_bs_factor);
1850                 position = idetape_read_position(drive);
1851                 if (position < 0)
1852                         return -EIO;
1853         }
1854         switch (cmd) {
1855         case MTIOCTOP:
1856                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1857                         return -EFAULT;
1858                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1859         case MTIOCGET:
1860                 memset(&mtget, 0, sizeof(struct mtget));
1861                 mtget.mt_type = MT_ISSCSI2;
1862                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1863                 mtget.mt_dsreg =
1864                         ((tape->blk_size * tape->user_bs_factor)
1865                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1866
1867                 if (tape->drv_write_prot)
1868                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1869
1870                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1871                         return -EFAULT;
1872                 return 0;
1873         case MTIOCPOS:
1874                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1875                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1876                         return -EFAULT;
1877                 return 0;
1878         default:
1879                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1880                         ide_tape_discard_merge_buffer(drive, 1);
1881                 return idetape_blkdev_ioctl(drive, cmd, arg);
1882         }
1883 }
1884
1885 /*
1886  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1887  * block size with the reported value.
1888  */
1889 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1890 {
1891         idetape_tape_t *tape = drive->driver_data;
1892         struct ide_atapi_pc pc;
1893
1894         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1895         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1896                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1897                 if (tape->blk_size == 0) {
1898                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1899                                             "block size, assuming 32k\n");
1900                         tape->blk_size = 32768;
1901                 }
1902                 return;
1903         }
1904         tape->blk_size = (pc.buf[4 + 5] << 16) +
1905                                 (pc.buf[4 + 6] << 8)  +
1906                                  pc.buf[4 + 7];
1907         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1908 }
1909
1910 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1911 {
1912         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1913         ide_drive_t *drive;
1914         idetape_tape_t *tape;
1915         int retval;
1916
1917         if (i >= MAX_HWIFS * MAX_DRIVES)
1918                 return -ENXIO;
1919
1920         lock_kernel();
1921         tape = ide_tape_chrdev_get(i);
1922         if (!tape) {
1923                 unlock_kernel();
1924                 return -ENXIO;
1925         }
1926
1927         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1928
1929         /*
1930          * We really want to do nonseekable_open(inode, filp); here, but some
1931          * versions of tar incorrectly call lseek on tapes and bail out if that
1932          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1933          */
1934         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1935
1936         drive = tape->drive;
1937
1938         filp->private_data = tape;
1939
1940         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1941                 retval = -EBUSY;
1942                 goto out_put_tape;
1943         }
1944
1945         retval = idetape_wait_ready(drive, 60 * HZ);
1946         if (retval) {
1947                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1948                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1949                 goto out_put_tape;
1950         }
1951
1952         idetape_read_position(drive);
1953         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1954                 (void)idetape_rewind_tape(drive);
1955
1956         /* Read block size and write protect status from drive. */
1957         ide_tape_get_bsize_from_bdesc(drive);
1958
1959         /* Set write protect flag if device is opened as read-only. */
1960         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1961                 tape->write_prot = 1;
1962         else
1963                 tape->write_prot = tape->drv_write_prot;
1964
1965         /* Make sure drive isn't write protected if user wants to write. */
1966         if (tape->write_prot) {
1967                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1968                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1969                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1970                         retval = -EROFS;
1971                         goto out_put_tape;
1972                 }
1973         }
1974
1975         /* Lock the tape drive door so user can't eject. */
1976         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1977                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1978                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1979                                 tape->door_locked = DOOR_LOCKED;
1980                 }
1981         }
1982         unlock_kernel();
1983         return 0;
1984
1985 out_put_tape:
1986         ide_tape_put(tape);
1987         unlock_kernel();
1988         return retval;
1989 }
1990
1991 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
1992 {
1993         idetape_tape_t *tape = drive->driver_data;
1994
1995         ide_tape_flush_merge_buffer(drive);
1996         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
1997         if (tape->merge_bh != NULL) {
1998                 idetape_pad_zeros(drive, tape->blk_size *
1999                                 (tape->user_bs_factor - 1));
2000                 ide_tape_kfree_buffer(tape);
2001                 tape->merge_bh = NULL;
2002         }
2003         idetape_write_filemark(drive);
2004         idetape_flush_tape_buffers(drive);
2005         idetape_flush_tape_buffers(drive);
2006 }
2007
2008 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2009 {
2010         struct ide_tape_obj *tape = filp->private_data;
2011         ide_drive_t *drive = tape->drive;
2012         unsigned int minor = iminor(inode);
2013
2014         lock_kernel();
2015         tape = drive->driver_data;
2016
2017         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2018
2019         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2020                 idetape_write_release(drive, minor);
2021         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2022                 if (minor < 128)
2023                         ide_tape_discard_merge_buffer(drive, 1);
2024         }
2025
2026         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2027                 (void) idetape_rewind_tape(drive);
2028         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2029                 if (tape->door_locked == DOOR_LOCKED) {
2030                         if (!ide_set_media_lock(drive, tape->disk, 0))
2031                                 tape->door_locked = DOOR_UNLOCKED;
2032                 }
2033         }
2034         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2035         ide_tape_put(tape);
2036         unlock_kernel();
2037         return 0;
2038 }
2039
2040 static void idetape_get_inquiry_results(ide_drive_t *drive)
2041 {
2042         idetape_tape_t *tape = drive->driver_data;
2043         struct ide_atapi_pc pc;
2044         char fw_rev[4], vendor_id[8], product_id[16];
2045
2046         idetape_create_inquiry_cmd(&pc);
2047         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2048                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2049                                 tape->name);
2050                 return;
2051         }
2052         memcpy(vendor_id, &pc.buf[8], 8);
2053         memcpy(product_id, &pc.buf[16], 16);
2054         memcpy(fw_rev, &pc.buf[32], 4);
2055
2056         ide_fixstring(vendor_id, 8, 0);
2057         ide_fixstring(product_id, 16, 0);
2058         ide_fixstring(fw_rev, 4, 0);
2059
2060         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2061                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2062 }
2063
2064 /*
2065  * Ask the tape about its various parameters. In particular, we will adjust our
2066  * data transfer buffer size to the recommended value as returned by the tape.
2067  */
2068 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2069 {
2070         idetape_tape_t *tape = drive->driver_data;
2071         struct ide_atapi_pc pc;
2072         u8 *caps;
2073         u8 speed, max_speed;
2074
2075         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2076         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2077                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2078                                 " some default values\n");
2079                 tape->blk_size = 512;
2080                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2081                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2082                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2083                 return;
2084         }
2085         caps = pc.buf + 4 + pc.buf[3];
2086
2087         /* convert to host order and save for later use */
2088         speed = be16_to_cpup((__be16 *)&caps[14]);
2089         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2090
2091         *(u16 *)&caps[8] = max_speed;
2092         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2093         *(u16 *)&caps[14] = speed;
2094         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2095
2096         if (!speed) {
2097                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2098                                 "(assuming 650KB/sec)\n", drive->name);
2099                 *(u16 *)&caps[14] = 650;
2100         }
2101         if (!max_speed) {
2102                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2103                                 "(assuming 650KB/sec)\n", drive->name);
2104                 *(u16 *)&caps[8] = 650;
2105         }
2106
2107         memcpy(&tape->caps, caps, 20);
2108
2109         /* device lacks locking support according to capabilities page */
2110         if ((caps[6] & 1) == 0)
2111                 drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;
2112
2113         if (caps[7] & 0x02)
2114                 tape->blk_size = 512;
2115         else if (caps[7] & 0x04)
2116                 tape->blk_size = 1024;
2117 }
2118
2119 #ifdef CONFIG_IDE_PROC_FS
2120 #define ide_tape_devset_get(name, field) \
2121 static int get_##name(ide_drive_t *drive) \
2122 { \
2123         idetape_tape_t *tape = drive->driver_data; \
2124         return tape->field; \
2125 }
2126
2127 #define ide_tape_devset_set(name, field) \
2128 static int set_##name(ide_drive_t *drive, int arg) \
2129 { \
2130         idetape_tape_t *tape = drive->driver_data; \
2131         tape->field = arg; \
2132         return 0; \
2133 }
2134
2135 #define ide_tape_devset_rw_field(_name, _field) \
2136 ide_tape_devset_get(_name, _field) \
2137 ide_tape_devset_set(_name, _field) \
2138 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2139
2140 #define ide_tape_devset_r_field(_name, _field) \
2141 ide_tape_devset_get(_name, _field) \
2142 IDE_DEVSET(_name, 0, get_##_name, NULL)
2143
2144 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2145 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2146 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2147 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2148
2149 ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);
2150
2151 ide_tape_devset_rw_field(debug_mask, debug_mask);
2152 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2153
2154 ide_tape_devset_r_field(avg_speed, avg_speed);
2155 ide_tape_devset_r_field(speed, caps[14]);
2156 ide_tape_devset_r_field(buffer, caps[16]);
2157 ide_tape_devset_r_field(buffer_size, buffer_size);
2158
2159 static const struct ide_proc_devset idetape_settings[] = {
2160         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2161         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2162         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2163         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2164         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2165         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2166         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2167                                         mulf_tdsc, divf_tdsc),
2168         { 0 },
2169 };
2170 #endif
2171
2172 /*
2173  * The function below is called to:
2174  *
2175  * 1. Initialize our various state variables.
2176  * 2. Ask the tape for its capabilities.
2177  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2178  * is chosen based on the recommendation which we received in step 2.
2179  *
2180  * Note that at this point ide.c already assigned us an irq, so that we can
2181  * queue requests here and wait for their completion.
2182  */
2183 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2184 {
2185         unsigned long t;
2186         int speed;
2187         int buffer_size;
2188         u16 *ctl = (u16 *)&tape->caps[12];
2189
2190         drive->pc_callback       = ide_tape_callback;
2191         drive->pc_update_buffers = idetape_update_buffers;
2192         drive->pc_io_buffers     = ide_tape_io_buffers;
2193
2194         spin_lock_init(&tape->lock);
2195
2196         drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
2197
2198         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2199                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2200                                  tape->name);
2201                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2202         }
2203
2204         /* Seagate Travan drives do not support DSC overlap. */
2205         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2206                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2207
2208         tape->minor = minor;
2209         tape->name[0] = 'h';
2210         tape->name[1] = 't';
2211         tape->name[2] = '0' + minor;
2212         tape->chrdev_dir = IDETAPE_DIR_NONE;
2213
2214         idetape_get_inquiry_results(drive);
2215         idetape_get_mode_sense_results(drive);
2216         ide_tape_get_bsize_from_bdesc(drive);
2217         tape->user_bs_factor = 1;
2218         tape->buffer_size = *ctl * tape->blk_size;
2219         while (tape->buffer_size > 0xffff) {
2220                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2221                 *ctl /= 2;
2222                 tape->buffer_size = *ctl * tape->blk_size;
2223         }
2224         buffer_size = tape->buffer_size;
2225         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2226         if (buffer_size % PAGE_SIZE) {
2227                 tape->pages_per_buffer++;
2228                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2229         }
2230
2231         /* select the "best" DSC read/write polling freq */
2232         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2233
2234         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2235
2236         /*
2237          * Ensure that the number we got makes sense; limit it within
2238          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2239          */
2240         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2241                                          IDETAPE_DSC_RW_MAX);
2242         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2243                 "%lums tDSC%s\n",
2244                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2245                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2246                 tape->buffer_size / 1024,
2247                 tape->best_dsc_rw_freq * 1000 / HZ,
2248                 (drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");
2249
2250         ide_proc_register_driver(drive, tape->driver);
2251 }
2252
2253 static void ide_tape_remove(ide_drive_t *drive)
2254 {
2255         idetape_tape_t *tape = drive->driver_data;
2256
2257         ide_proc_unregister_driver(drive, tape->driver);
2258
2259         ide_unregister_region(tape->disk);
2260
2261         ide_tape_put(tape);
2262 }
2263
2264 static void ide_tape_release(struct kref *kref)
2265 {
2266         struct ide_tape_obj *tape = to_ide_drv(kref, ide_tape_obj);
2267         ide_drive_t *drive = tape->drive;
2268         struct gendisk *g = tape->disk;
2269
2270         BUG_ON(tape->merge_bh_size);
2271
2272         drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2273         drive->driver_data = NULL;
2274         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2275         device_destroy(idetape_sysfs_class,
2276                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2277         idetape_devs[tape->minor] = NULL;
2278         g->private_data = NULL;
2279         put_disk(g);
2280         kfree(tape);
2281 }
2282
2283 #ifdef CONFIG_IDE_PROC_FS
2284 static int proc_idetape_read_name
2285         (char *page, char **start, off_t off, int count, int *eof, void *data)
2286 {
2287         ide_drive_t     *drive = (ide_drive_t *) data;
2288         idetape_tape_t  *tape = drive->driver_data;
2289         char            *out = page;
2290         int             len;
2291
2292         len = sprintf(out, "%s\n", tape->name);
2293         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2294 }
2295
2296 static ide_proc_entry_t idetape_proc[] = {
2297         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2298         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2299         { NULL, 0, NULL, NULL }
2300 };
2301
2302 static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive)
2303 {
2304         return idetape_proc;
2305 }
2306
2307 static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive)
2308 {
2309         return idetape_settings;
2310 }
2311 #endif
2312
2313 static int ide_tape_probe(ide_drive_t *);
2314
2315 static ide_driver_t idetape_driver = {
2316         .gen_driver = {
2317                 .owner          = THIS_MODULE,
2318                 .name           = "ide-tape",
2319                 .bus            = &ide_bus_type,
2320         },
2321         .probe                  = ide_tape_probe,
2322         .remove                 = ide_tape_remove,
2323         .version                = IDETAPE_VERSION,
2324         .do_request             = idetape_do_request,
2325         .end_request            = idetape_end_request,
2326         .error                  = __ide_error,
2327 #ifdef CONFIG_IDE_PROC_FS
2328         .proc_entries           = ide_tape_proc_entries,
2329         .proc_devsets           = ide_tape_proc_devsets,
2330 #endif
2331 };
2332
2333 /* Our character device supporting functions, passed to register_chrdev. */
2334 static const struct file_operations idetape_fops = {
2335         .owner          = THIS_MODULE,
2336         .read           = idetape_chrdev_read,
2337         .write          = idetape_chrdev_write,
2338         .ioctl          = idetape_chrdev_ioctl,
2339         .open           = idetape_chrdev_open,
2340         .release        = idetape_chrdev_release,
2341 };
2342
2343 static int idetape_open(struct block_device *bdev, fmode_t mode)
2344 {
2345         struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk);
2346
2347         if (!tape)
2348                 return -ENXIO;
2349
2350         return 0;
2351 }
2352
2353 static int idetape_release(struct gendisk *disk, fmode_t mode)
2354 {
2355         struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
2356
2357         ide_tape_put(tape);
2358         return 0;
2359 }
2360
2361 static int idetape_ioctl(struct block_device *bdev, fmode_t mode,
2362                         unsigned int cmd, unsigned long arg)
2363 {
2364         struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
2365         ide_drive_t *drive = tape->drive;
2366         int err = generic_ide_ioctl(drive, bdev, cmd, arg);
2367         if (err == -EINVAL)
2368                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2369         return err;
2370 }
2371
2372 static struct block_device_operations idetape_block_ops = {
2373         .owner          = THIS_MODULE,
2374         .open           = idetape_open,
2375         .release        = idetape_release,
2376         .locked_ioctl   = idetape_ioctl,
2377 };
2378
2379 static int ide_tape_probe(ide_drive_t *drive)
2380 {
2381         idetape_tape_t *tape;
2382         struct gendisk *g;
2383         int minor;
2384
2385         if (!strstr("ide-tape", drive->driver_req))
2386                 goto failed;
2387
2388         if (drive->media != ide_tape)
2389                 goto failed;
2390
2391         if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&
2392             ide_check_atapi_device(drive, DRV_NAME) == 0) {
2393                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2394                                 " the driver\n", drive->name);
2395                 goto failed;
2396         }
2397         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2398         if (tape == NULL) {
2399                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2400                                 drive->name);
2401                 goto failed;
2402         }
2403
2404         g = alloc_disk(1 << PARTN_BITS);
2405         if (!g)
2406                 goto out_free_tape;
2407
2408         ide_init_disk(g, drive);
2409
2410         kref_init(&tape->kref);
2411
2412         tape->drive = drive;
2413         tape->driver = &idetape_driver;
2414         tape->disk = g;
2415
2416         g->private_data = &tape->driver;
2417
2418         drive->driver_data = tape;
2419
2420         mutex_lock(&idetape_ref_mutex);
2421         for (minor = 0; idetape_devs[minor]; minor++)
2422                 ;
2423         idetape_devs[minor] = tape;
2424         mutex_unlock(&idetape_ref_mutex);
2425
2426         idetape_setup(drive, tape, minor);
2427
2428         device_create(idetape_sysfs_class, &drive->gendev,
2429                       MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);
2430         device_create(idetape_sysfs_class, &drive->gendev,
2431                       MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2432                       "n%s", tape->name);
2433
2434         g->fops = &idetape_block_ops;
2435         ide_register_region(g);
2436
2437         return 0;
2438
2439 out_free_tape:
2440         kfree(tape);
2441 failed:
2442         return -ENODEV;
2443 }
2444
2445 static void __exit idetape_exit(void)
2446 {
2447         driver_unregister(&idetape_driver.gen_driver);
2448         class_destroy(idetape_sysfs_class);
2449         unregister_chrdev(IDETAPE_MAJOR, "ht");
2450 }
2451
2452 static int __init idetape_init(void)
2453 {
2454         int error = 1;
2455         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2456         if (IS_ERR(idetape_sysfs_class)) {
2457                 idetape_sysfs_class = NULL;
2458                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2459                 error = -EBUSY;
2460                 goto out;
2461         }
2462
2463         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2464                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2465                                 " interface\n");
2466                 error = -EBUSY;
2467                 goto out_free_class;
2468         }
2469
2470         error = driver_register(&idetape_driver.gen_driver);
2471         if (error)
2472                 goto out_free_driver;
2473
2474         return 0;
2475
2476 out_free_driver:
2477         driver_unregister(&idetape_driver.gen_driver);
2478 out_free_class:
2479         class_destroy(idetape_sysfs_class);
2480 out:
2481         return error;
2482 }
2483
2484 MODULE_ALIAS("ide:*m-tape*");
2485 module_init(idetape_init);
2486 module_exit(idetape_exit);
2487 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2488 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2489 MODULE_LICENSE("GPL");