Merge branch 'master' into next
[linux-2.6] / drivers / ide / ide-tape.c
1 /*
2  * IDE ATAPI streaming tape driver.
3  *
4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
6  *
7  * This driver was constructed as a student project in the software laboratory
8  * of the faculty of electrical engineering in the Technion - Israel's
9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
10  *
11  * It is hereby placed under the terms of the GNU general public license.
12  * (See linux/COPYING).
13  *
14  * For a historical changelog see
15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
16  */
17
18 #define DRV_NAME "ide-tape"
19
20 #define IDETAPE_VERSION "1.20"
21
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/kernel.h>
26 #include <linux/delay.h>
27 #include <linux/timer.h>
28 #include <linux/mm.h>
29 #include <linux/interrupt.h>
30 #include <linux/jiffies.h>
31 #include <linux/major.h>
32 #include <linux/errno.h>
33 #include <linux/genhd.h>
34 #include <linux/slab.h>
35 #include <linux/pci.h>
36 #include <linux/ide.h>
37 #include <linux/smp_lock.h>
38 #include <linux/completion.h>
39 #include <linux/bitops.h>
40 #include <linux/mutex.h>
41 #include <scsi/scsi.h>
42
43 #include <asm/byteorder.h>
44 #include <linux/irq.h>
45 #include <linux/uaccess.h>
46 #include <linux/io.h>
47 #include <asm/unaligned.h>
48 #include <linux/mtio.h>
49
50 enum {
51         /* output errors only */
52         DBG_ERR =               (1 << 0),
53         /* output all sense key/asc */
54         DBG_SENSE =             (1 << 1),
55         /* info regarding all chrdev-related procedures */
56         DBG_CHRDEV =            (1 << 2),
57         /* all remaining procedures */
58         DBG_PROCS =             (1 << 3),
59 };
60
61 /* define to see debug info */
62 #define IDETAPE_DEBUG_LOG               0
63
64 #if IDETAPE_DEBUG_LOG
65 #define debug_log(lvl, fmt, args...)                    \
66 {                                                       \
67         if (tape->debug_mask & lvl)                     \
68         printk(KERN_INFO "ide-tape: " fmt, ## args);    \
69 }
70 #else
71 #define debug_log(lvl, fmt, args...) do {} while (0)
72 #endif
73
74 /**************************** Tunable parameters *****************************/
75 /*
76  * After each failed packet command we issue a request sense command and retry
77  * the packet command IDETAPE_MAX_PC_RETRIES times.
78  *
79  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
80  */
81 #define IDETAPE_MAX_PC_RETRIES          3
82
83 /*
84  * The following parameter is used to select the point in the internal tape fifo
85  * in which we will start to refill the buffer. Decreasing the following
86  * parameter will improve the system's latency and interactive response, while
87  * using a high value might improve system throughput.
88  */
89 #define IDETAPE_FIFO_THRESHOLD          2
90
91 /*
92  * DSC polling parameters.
93  *
94  * Polling for DSC (a single bit in the status register) is a very important
95  * function in ide-tape. There are two cases in which we poll for DSC:
96  *
97  * 1. Before a read/write packet command, to ensure that we can transfer data
98  * from/to the tape's data buffers, without causing an actual media access.
99  * In case the tape is not ready yet, we take out our request from the device
100  * request queue, so that ide.c could service requests from the other device
101  * on the same interface in the meantime.
102  *
103  * 2. After the successful initialization of a "media access packet command",
104  * which is a command that can take a long time to complete (the interval can
105  * range from several seconds to even an hour). Again, we postpone our request
106  * in the middle to free the bus for the other device. The polling frequency
107  * here should be lower than the read/write frequency since those media access
108  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
109  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
110  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
111  *
112  * We also set a timeout for the timer, in case something goes wrong. The
113  * timeout should be longer then the maximum execution time of a tape operation.
114  */
115
116 /* DSC timings. */
117 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
118 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
119 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
120 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
121 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
122 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
123 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
124
125 /*************************** End of tunable parameters ***********************/
126
127 /* tape directions */
128 enum {
129         IDETAPE_DIR_NONE  = (1 << 0),
130         IDETAPE_DIR_READ  = (1 << 1),
131         IDETAPE_DIR_WRITE = (1 << 2),
132 };
133
134 struct idetape_bh {
135         u32 b_size;
136         atomic_t b_count;
137         struct idetape_bh *b_reqnext;
138         char *b_data;
139 };
140
141 /* Tape door status */
142 #define DOOR_UNLOCKED                   0
143 #define DOOR_LOCKED                     1
144 #define DOOR_EXPLICITLY_LOCKED          2
145
146 /* Some defines for the SPACE command */
147 #define IDETAPE_SPACE_OVER_FILEMARK     1
148 #define IDETAPE_SPACE_TO_EOD            3
149
150 /* Some defines for the LOAD UNLOAD command */
151 #define IDETAPE_LU_LOAD_MASK            1
152 #define IDETAPE_LU_RETENSION_MASK       2
153 #define IDETAPE_LU_EOT_MASK             4
154
155 /* Error codes returned in rq->errors to the higher part of the driver. */
156 #define IDETAPE_ERROR_GENERAL           101
157 #define IDETAPE_ERROR_FILEMARK          102
158 #define IDETAPE_ERROR_EOD               103
159
160 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
161 #define IDETAPE_BLOCK_DESCRIPTOR        0
162 #define IDETAPE_CAPABILITIES_PAGE       0x2a
163
164 /*
165  * Most of our global data which we need to save even as we leave the driver due
166  * to an interrupt or a timer event is stored in the struct defined below.
167  */
168 typedef struct ide_tape_obj {
169         ide_drive_t             *drive;
170         struct ide_driver       *driver;
171         struct gendisk          *disk;
172         struct device           dev;
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 device *);
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                         get_device(&tape->dev);
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         put_device(&tape->dev);
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                 get_device(&tape->dev);
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 = drive->hwif->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->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 port 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 = drive->hwif->rq;
588
589         ide_stall_queue(drive, tape->dsc_poll_freq);
590 }
591
592 static void ide_tape_handle_dsc(ide_drive_t *drive)
593 {
594         idetape_tape_t *tape = drive->driver_data;
595
596         /* Media access command */
597         tape->dsc_polling_start = jiffies;
598         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
599         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
600         /* Allow ide.c to handle other requests */
601         idetape_postpone_request(drive);
602 }
603
604 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
605                                 unsigned int bcount, int write)
606 {
607         if (write)
608                 idetape_output_buffers(drive, pc, bcount);
609         else
610                 idetape_input_buffers(drive, pc, bcount);
611
612         return bcount;
613 }
614
615 /*
616  * Packet Command Interface
617  *
618  * The current Packet Command is available in drive->pc, and will not change
619  * until we finish handling it. Each packet command is associated with a
620  * callback function that will be called when the command is finished.
621  *
622  * The handling will be done in three stages:
623  *
624  * 1. idetape_issue_pc will send the packet command to the drive, and will set
625  * the interrupt handler to ide_pc_intr.
626  *
627  * 2. On each interrupt, ide_pc_intr will be called. This step will be
628  * repeated until the device signals us that no more interrupts will be issued.
629  *
630  * 3. ATAPI Tape media access commands have immediate status with a delayed
631  * process. In case of a successful initiation of a media access packet command,
632  * the DSC bit will be set when the actual execution of the command is finished.
633  * Since the tape drive will not issue an interrupt, we have to poll for this
634  * event. In this case, we define the request as "low priority request" by
635  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
636  * exit the driver.
637  *
638  * ide.c will then give higher priority to requests which originate from the
639  * other device, until will change rq_status to RQ_ACTIVE.
640  *
641  * 4. When the packet command is finished, it will be checked for errors.
642  *
643  * 5. In case an error was found, we queue a request sense packet command in
644  * front of the request queue and retry the operation up to
645  * IDETAPE_MAX_PC_RETRIES times.
646  *
647  * 6. In case no error was found, or we decided to give up and not to retry
648  * again, the callback function will be called and then we will handle the next
649  * request.
650  */
651
652 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
653                 struct ide_atapi_pc *pc)
654 {
655         idetape_tape_t *tape = drive->driver_data;
656
657         if (drive->pc->c[0] == REQUEST_SENSE &&
658             pc->c[0] == REQUEST_SENSE) {
659                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
660                         "Two request sense in serial were issued\n");
661         }
662
663         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
664                 tape->failed_pc = pc;
665
666         /* Set the current packet command */
667         drive->pc = pc;
668
669         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
670                 (pc->flags & PC_FLAG_ABORT)) {
671                 /*
672                  * We will "abort" retrying a packet command in case legitimate
673                  * error code was received (crossing a filemark, or end of the
674                  * media, for example).
675                  */
676                 if (!(pc->flags & PC_FLAG_ABORT)) {
677                         if (!(pc->c[0] == TEST_UNIT_READY &&
678                               tape->sense_key == 2 && tape->asc == 4 &&
679                              (tape->ascq == 1 || tape->ascq == 8))) {
680                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
681                                                 "pc = %2x, key = %2x, "
682                                                 "asc = %2x, ascq = %2x\n",
683                                                 tape->name, pc->c[0],
684                                                 tape->sense_key, tape->asc,
685                                                 tape->ascq);
686                         }
687                         /* Giving up */
688                         pc->error = IDETAPE_ERROR_GENERAL;
689                 }
690                 tape->failed_pc = NULL;
691                 drive->pc_callback(drive, 0);
692                 return ide_stopped;
693         }
694         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
695
696         pc->retries++;
697
698         return ide_issue_pc(drive);
699 }
700
701 /* A mode sense command is used to "sense" tape parameters. */
702 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
703 {
704         ide_init_pc(pc);
705         pc->c[0] = MODE_SENSE;
706         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
707                 /* DBD = 1 - Don't return block descriptors */
708                 pc->c[1] = 8;
709         pc->c[2] = page_code;
710         /*
711          * Changed pc->c[3] to 0 (255 will at best return unused info).
712          *
713          * For SCSI this byte is defined as subpage instead of high byte
714          * of length and some IDE drives seem to interpret it this way
715          * and return an error when 255 is used.
716          */
717         pc->c[3] = 0;
718         /* We will just discard data in that case */
719         pc->c[4] = 255;
720         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
721                 pc->req_xfer = 12;
722         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
723                 pc->req_xfer = 24;
724         else
725                 pc->req_xfer = 50;
726 }
727
728 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
729 {
730         ide_hwif_t *hwif = drive->hwif;
731         idetape_tape_t *tape = drive->driver_data;
732         struct ide_atapi_pc *pc = drive->pc;
733         u8 stat;
734
735         stat = hwif->tp_ops->read_status(hwif);
736
737         if (stat & ATA_DSC) {
738                 if (stat & ATA_ERR) {
739                         /* Error detected */
740                         if (pc->c[0] != TEST_UNIT_READY)
741                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
742                                                 tape->name);
743                         /* Retry operation */
744                         ide_retry_pc(drive, tape->disk);
745                         return ide_stopped;
746                 }
747                 pc->error = 0;
748         } else {
749                 pc->error = IDETAPE_ERROR_GENERAL;
750                 tape->failed_pc = NULL;
751         }
752         drive->pc_callback(drive, 0);
753         return ide_stopped;
754 }
755
756 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
757                                    struct ide_atapi_pc *pc, struct request *rq,
758                                    u8 opcode)
759 {
760         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
761         unsigned int length = rq->current_nr_sectors;
762
763         ide_init_pc(pc);
764         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
765         pc->c[1] = 1;
766         pc->bh = bh;
767         pc->buf = NULL;
768         pc->buf_size = length * tape->blk_size;
769         pc->req_xfer = pc->buf_size;
770         if (pc->req_xfer == tape->buffer_size)
771                 pc->flags |= PC_FLAG_DMA_OK;
772
773         if (opcode == READ_6) {
774                 pc->c[0] = READ_6;
775                 atomic_set(&bh->b_count, 0);
776         } else if (opcode == WRITE_6) {
777                 pc->c[0] = WRITE_6;
778                 pc->flags |= PC_FLAG_WRITING;
779                 pc->b_data = bh->b_data;
780                 pc->b_count = atomic_read(&bh->b_count);
781         }
782
783         memcpy(rq->cmd, pc->c, 12);
784 }
785
786 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
787                                           struct request *rq, sector_t block)
788 {
789         ide_hwif_t *hwif = drive->hwif;
790         idetape_tape_t *tape = drive->driver_data;
791         struct ide_atapi_pc *pc = NULL;
792         struct request *postponed_rq = tape->postponed_rq;
793         u8 stat;
794
795         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
796                         " current_nr_sectors: %u\n",
797                         (unsigned long long)rq->sector, rq->nr_sectors,
798                         rq->current_nr_sectors);
799
800         if (!blk_special_request(rq)) {
801                 /* We do not support buffer cache originated requests. */
802                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
803                         "request queue (%d)\n", drive->name, rq->cmd_type);
804                 ide_end_request(drive, 0, 0);
805                 return ide_stopped;
806         }
807
808         /* Retry a failed packet command */
809         if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
810                 pc = tape->failed_pc;
811                 goto out;
812         }
813
814         if (postponed_rq != NULL)
815                 if (rq != postponed_rq) {
816                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
817                                         "Two DSC requests were queued\n");
818                         idetape_end_request(drive, 0, 0);
819                         return ide_stopped;
820                 }
821
822         tape->postponed_rq = NULL;
823
824         /*
825          * If the tape is still busy, postpone our request and service
826          * the other device meanwhile.
827          */
828         stat = hwif->tp_ops->read_status(hwif);
829
830         if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
831             (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
832                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
833
834         if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
835                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
836                 drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
837         }
838
839         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
840             (stat & ATA_DSC) == 0) {
841                 if (postponed_rq == NULL) {
842                         tape->dsc_polling_start = jiffies;
843                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
844                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
845                 } else if (time_after(jiffies, tape->dsc_timeout)) {
846                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
847                                 tape->name);
848                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
849                                 idetape_media_access_finished(drive);
850                                 return ide_stopped;
851                         } else {
852                                 return ide_do_reset(drive);
853                         }
854                 } else if (time_after(jiffies,
855                                         tape->dsc_polling_start +
856                                         IDETAPE_DSC_MA_THRESHOLD))
857                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
858                 idetape_postpone_request(drive);
859                 return ide_stopped;
860         }
861         if (rq->cmd[13] & REQ_IDETAPE_READ) {
862                 pc = &tape->queued_pc;
863                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
864                 goto out;
865         }
866         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
867                 pc = &tape->queued_pc;
868                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
869                 goto out;
870         }
871         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
872                 pc = (struct ide_atapi_pc *) rq->buffer;
873                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
874                 rq->cmd[13] |= REQ_IDETAPE_PC2;
875                 goto out;
876         }
877         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
878                 idetape_media_access_finished(drive);
879                 return ide_stopped;
880         }
881         BUG();
882
883 out:
884         return idetape_issue_pc(drive, pc);
885 }
886
887 /*
888  * The function below uses __get_free_pages to allocate a data buffer of size
889  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
890  * much as possible.
891  *
892  * It returns a pointer to the newly allocated buffer, or NULL in case of
893  * failure.
894  */
895 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
896                                                   int full, int clear)
897 {
898         struct idetape_bh *prev_bh, *bh, *merge_bh;
899         int pages = tape->pages_per_buffer;
900         unsigned int order, b_allocd;
901         char *b_data = NULL;
902
903         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
904         bh = merge_bh;
905         if (bh == NULL)
906                 goto abort;
907
908         order = fls(pages) - 1;
909         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
910         if (!bh->b_data)
911                 goto abort;
912         b_allocd = (1 << order) * PAGE_SIZE;
913         pages &= (order-1);
914
915         if (clear)
916                 memset(bh->b_data, 0, b_allocd);
917         bh->b_reqnext = NULL;
918         bh->b_size = b_allocd;
919         atomic_set(&bh->b_count, full ? bh->b_size : 0);
920
921         while (pages) {
922                 order = fls(pages) - 1;
923                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
924                 if (!b_data)
925                         goto abort;
926                 b_allocd = (1 << order) * PAGE_SIZE;
927
928                 if (clear)
929                         memset(b_data, 0, b_allocd);
930
931                 /* newly allocated page frames below buffer header or ...*/
932                 if (bh->b_data == b_data + b_allocd) {
933                         bh->b_size += b_allocd;
934                         bh->b_data -= b_allocd;
935                         if (full)
936                                 atomic_add(b_allocd, &bh->b_count);
937                         continue;
938                 }
939                 /* they are above the header */
940                 if (b_data == bh->b_data + bh->b_size) {
941                         bh->b_size += b_allocd;
942                         if (full)
943                                 atomic_add(b_allocd, &bh->b_count);
944                         continue;
945                 }
946                 prev_bh = bh;
947                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
948                 if (!bh) {
949                         free_pages((unsigned long) b_data, order);
950                         goto abort;
951                 }
952                 bh->b_reqnext = NULL;
953                 bh->b_data = b_data;
954                 bh->b_size = b_allocd;
955                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
956                 prev_bh->b_reqnext = bh;
957
958                 pages &= (order-1);
959         }
960
961         bh->b_size -= tape->excess_bh_size;
962         if (full)
963                 atomic_sub(tape->excess_bh_size, &bh->b_count);
964         return merge_bh;
965 abort:
966         ide_tape_kfree_buffer(tape);
967         return NULL;
968 }
969
970 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
971                                         const char __user *buf, int n)
972 {
973         struct idetape_bh *bh = tape->bh;
974         int count;
975         int ret = 0;
976
977         while (n) {
978                 if (bh == NULL) {
979                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
980                                         __func__);
981                         return 1;
982                 }
983                 count = min((unsigned int)
984                                 (bh->b_size - atomic_read(&bh->b_count)),
985                                 (unsigned int)n);
986                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
987                                 count))
988                         ret = 1;
989                 n -= count;
990                 atomic_add(count, &bh->b_count);
991                 buf += count;
992                 if (atomic_read(&bh->b_count) == bh->b_size) {
993                         bh = bh->b_reqnext;
994                         if (bh)
995                                 atomic_set(&bh->b_count, 0);
996                 }
997         }
998         tape->bh = bh;
999         return ret;
1000 }
1001
1002 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1003                                       int n)
1004 {
1005         struct idetape_bh *bh = tape->bh;
1006         int count;
1007         int ret = 0;
1008
1009         while (n) {
1010                 if (bh == NULL) {
1011                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1012                                         __func__);
1013                         return 1;
1014                 }
1015                 count = min(tape->b_count, n);
1016                 if  (copy_to_user(buf, tape->b_data, count))
1017                         ret = 1;
1018                 n -= count;
1019                 tape->b_data += count;
1020                 tape->b_count -= count;
1021                 buf += count;
1022                 if (!tape->b_count) {
1023                         bh = bh->b_reqnext;
1024                         tape->bh = bh;
1025                         if (bh) {
1026                                 tape->b_data = bh->b_data;
1027                                 tape->b_count = atomic_read(&bh->b_count);
1028                         }
1029                 }
1030         }
1031         return ret;
1032 }
1033
1034 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1035 {
1036         struct idetape_bh *bh = tape->merge_bh;
1037         tape->bh = tape->merge_bh;
1038
1039         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1040                 atomic_set(&bh->b_count, 0);
1041         else {
1042                 tape->b_data = bh->b_data;
1043                 tape->b_count = atomic_read(&bh->b_count);
1044         }
1045 }
1046
1047 /*
1048  * Write a filemark if write_filemark=1. Flush the device buffers without
1049  * writing a filemark otherwise.
1050  */
1051 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1052                 struct ide_atapi_pc *pc, int write_filemark)
1053 {
1054         ide_init_pc(pc);
1055         pc->c[0] = WRITE_FILEMARKS;
1056         pc->c[4] = write_filemark;
1057         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1058 }
1059
1060 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1061 {
1062         idetape_tape_t *tape = drive->driver_data;
1063         struct gendisk *disk = tape->disk;
1064         int load_attempted = 0;
1065
1066         /* Wait for the tape to become ready */
1067         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1068         timeout += jiffies;
1069         while (time_before(jiffies, timeout)) {
1070                 if (ide_do_test_unit_ready(drive, disk) == 0)
1071                         return 0;
1072                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1073                     || (tape->asc == 0x3A)) {
1074                         /* no media */
1075                         if (load_attempted)
1076                                 return -ENOMEDIUM;
1077                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1078                         load_attempted = 1;
1079                 /* not about to be ready */
1080                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1081                              (tape->ascq == 1 || tape->ascq == 8)))
1082                         return -EIO;
1083                 msleep(100);
1084         }
1085         return -EIO;
1086 }
1087
1088 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1089 {
1090         struct ide_tape_obj *tape = drive->driver_data;
1091         struct ide_atapi_pc pc;
1092         int rc;
1093
1094         idetape_create_write_filemark_cmd(drive, &pc, 0);
1095         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1096         if (rc)
1097                 return rc;
1098         idetape_wait_ready(drive, 60 * 5 * HZ);
1099         return 0;
1100 }
1101
1102 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1103 {
1104         ide_init_pc(pc);
1105         pc->c[0] = READ_POSITION;
1106         pc->req_xfer = 20;
1107 }
1108
1109 static int idetape_read_position(ide_drive_t *drive)
1110 {
1111         idetape_tape_t *tape = drive->driver_data;
1112         struct ide_atapi_pc pc;
1113         int position;
1114
1115         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1116
1117         idetape_create_read_position_cmd(&pc);
1118         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1119                 return -1;
1120         position = tape->first_frame;
1121         return position;
1122 }
1123
1124 static void idetape_create_locate_cmd(ide_drive_t *drive,
1125                 struct ide_atapi_pc *pc,
1126                 unsigned int block, u8 partition, int skip)
1127 {
1128         ide_init_pc(pc);
1129         pc->c[0] = POSITION_TO_ELEMENT;
1130         pc->c[1] = 2;
1131         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1132         pc->c[8] = partition;
1133         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1134 }
1135
1136 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1137 {
1138         idetape_tape_t *tape = drive->driver_data;
1139
1140         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1141                 return;
1142
1143         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1144         tape->merge_bh_size = 0;
1145         if (tape->merge_bh != NULL) {
1146                 ide_tape_kfree_buffer(tape);
1147                 tape->merge_bh = NULL;
1148         }
1149
1150         tape->chrdev_dir = IDETAPE_DIR_NONE;
1151 }
1152
1153 /*
1154  * Position the tape to the requested block using the LOCATE packet command.
1155  * A READ POSITION command is then issued to check where we are positioned. Like
1156  * all higher level operations, we queue the commands at the tail of the request
1157  * queue and wait for their completion.
1158  */
1159 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1160                 u8 partition, int skip)
1161 {
1162         idetape_tape_t *tape = drive->driver_data;
1163         struct gendisk *disk = tape->disk;
1164         int retval;
1165         struct ide_atapi_pc pc;
1166
1167         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1168                 __ide_tape_discard_merge_buffer(drive);
1169         idetape_wait_ready(drive, 60 * 5 * HZ);
1170         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1171         retval = ide_queue_pc_tail(drive, disk, &pc);
1172         if (retval)
1173                 return (retval);
1174
1175         idetape_create_read_position_cmd(&pc);
1176         return ide_queue_pc_tail(drive, disk, &pc);
1177 }
1178
1179 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1180                                           int restore_position)
1181 {
1182         idetape_tape_t *tape = drive->driver_data;
1183         int seek, position;
1184
1185         __ide_tape_discard_merge_buffer(drive);
1186         if (restore_position) {
1187                 position = idetape_read_position(drive);
1188                 seek = position > 0 ? position : 0;
1189                 if (idetape_position_tape(drive, seek, 0, 0)) {
1190                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1191                                          " %s\n", tape->name, __func__);
1192                         return;
1193                 }
1194         }
1195 }
1196
1197 /*
1198  * Generate a read/write request for the block device interface and wait for it
1199  * to be serviced.
1200  */
1201 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1202                                  struct idetape_bh *bh)
1203 {
1204         idetape_tape_t *tape = drive->driver_data;
1205         struct request *rq;
1206         int ret, errors;
1207
1208         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1209
1210         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1211         rq->cmd_type = REQ_TYPE_SPECIAL;
1212         rq->cmd[13] = cmd;
1213         rq->rq_disk = tape->disk;
1214         rq->special = (void *)bh;
1215         rq->sector = tape->first_frame;
1216         rq->nr_sectors = blocks;
1217         rq->current_nr_sectors = blocks;
1218         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1219
1220         errors = rq->errors;
1221         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1222         blk_put_request(rq);
1223
1224         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1225                 return 0;
1226
1227         if (tape->merge_bh)
1228                 idetape_init_merge_buffer(tape);
1229         if (errors == IDETAPE_ERROR_GENERAL)
1230                 return -EIO;
1231         return ret;
1232 }
1233
1234 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1235 {
1236         ide_init_pc(pc);
1237         pc->c[0] = INQUIRY;
1238         pc->c[4] = 254;
1239         pc->req_xfer = 254;
1240 }
1241
1242 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1243                 struct ide_atapi_pc *pc)
1244 {
1245         ide_init_pc(pc);
1246         pc->c[0] = REZERO_UNIT;
1247         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1248 }
1249
1250 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1251 {
1252         ide_init_pc(pc);
1253         pc->c[0] = ERASE;
1254         pc->c[1] = 1;
1255         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1256 }
1257
1258 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1259 {
1260         ide_init_pc(pc);
1261         pc->c[0] = SPACE;
1262         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1263         pc->c[1] = cmd;
1264         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1265 }
1266
1267 /* Queue up a character device originated write request. */
1268 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1269 {
1270         idetape_tape_t *tape = drive->driver_data;
1271
1272         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1273
1274         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1275                                      blocks, tape->merge_bh);
1276 }
1277
1278 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1279 {
1280         idetape_tape_t *tape = drive->driver_data;
1281         int blocks, min;
1282         struct idetape_bh *bh;
1283
1284         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1285                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1286                                 " but we are not writing.\n");
1287                 return;
1288         }
1289         if (tape->merge_bh_size > tape->buffer_size) {
1290                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1291                 tape->merge_bh_size = tape->buffer_size;
1292         }
1293         if (tape->merge_bh_size) {
1294                 blocks = tape->merge_bh_size / tape->blk_size;
1295                 if (tape->merge_bh_size % tape->blk_size) {
1296                         unsigned int i;
1297
1298                         blocks++;
1299                         i = tape->blk_size - tape->merge_bh_size %
1300                                 tape->blk_size;
1301                         bh = tape->bh->b_reqnext;
1302                         while (bh) {
1303                                 atomic_set(&bh->b_count, 0);
1304                                 bh = bh->b_reqnext;
1305                         }
1306                         bh = tape->bh;
1307                         while (i) {
1308                                 if (bh == NULL) {
1309                                         printk(KERN_INFO "ide-tape: bug,"
1310                                                          " bh NULL\n");
1311                                         break;
1312                                 }
1313                                 min = min(i, (unsigned int)(bh->b_size -
1314                                                 atomic_read(&bh->b_count)));
1315                                 memset(bh->b_data + atomic_read(&bh->b_count),
1316                                                 0, min);
1317                                 atomic_add(min, &bh->b_count);
1318                                 i -= min;
1319                                 bh = bh->b_reqnext;
1320                         }
1321                 }
1322                 (void) idetape_add_chrdev_write_request(drive, blocks);
1323                 tape->merge_bh_size = 0;
1324         }
1325         if (tape->merge_bh != NULL) {
1326                 ide_tape_kfree_buffer(tape);
1327                 tape->merge_bh = NULL;
1328         }
1329         tape->chrdev_dir = IDETAPE_DIR_NONE;
1330 }
1331
1332 static int idetape_init_read(ide_drive_t *drive)
1333 {
1334         idetape_tape_t *tape = drive->driver_data;
1335         int bytes_read;
1336
1337         /* Initialize read operation */
1338         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1339                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1340                         ide_tape_flush_merge_buffer(drive);
1341                         idetape_flush_tape_buffers(drive);
1342                 }
1343                 if (tape->merge_bh || tape->merge_bh_size) {
1344                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1345                                          " 0 now\n");
1346                         tape->merge_bh_size = 0;
1347                 }
1348                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1349                 if (!tape->merge_bh)
1350                         return -ENOMEM;
1351                 tape->chrdev_dir = IDETAPE_DIR_READ;
1352
1353                 /*
1354                  * Issue a read 0 command to ensure that DSC handshake is
1355                  * switched from completion mode to buffer available mode.
1356                  * No point in issuing this if DSC overlap isn't supported, some
1357                  * drives (Seagate STT3401A) will return an error.
1358                  */
1359                 if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
1360                         bytes_read = idetape_queue_rw_tail(drive,
1361                                                         REQ_IDETAPE_READ, 0,
1362                                                         tape->merge_bh);
1363                         if (bytes_read < 0) {
1364                                 ide_tape_kfree_buffer(tape);
1365                                 tape->merge_bh = NULL;
1366                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1367                                 return bytes_read;
1368                         }
1369                 }
1370         }
1371
1372         return 0;
1373 }
1374
1375 /* called from idetape_chrdev_read() to service a chrdev read request. */
1376 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1377 {
1378         idetape_tape_t *tape = drive->driver_data;
1379
1380         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1381
1382         /* If we are at a filemark, return a read length of 0 */
1383         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1384                 return 0;
1385
1386         idetape_init_read(drive);
1387
1388         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1389                                      tape->merge_bh);
1390 }
1391
1392 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1393 {
1394         idetape_tape_t *tape = drive->driver_data;
1395         struct idetape_bh *bh;
1396         int blocks;
1397
1398         while (bcount) {
1399                 unsigned int count;
1400
1401                 bh = tape->merge_bh;
1402                 count = min(tape->buffer_size, bcount);
1403                 bcount -= count;
1404                 blocks = count / tape->blk_size;
1405                 while (count) {
1406                         atomic_set(&bh->b_count,
1407                                    min(count, (unsigned int)bh->b_size));
1408                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1409                         count -= atomic_read(&bh->b_count);
1410                         bh = bh->b_reqnext;
1411                 }
1412                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1413                                       tape->merge_bh);
1414         }
1415 }
1416
1417 /*
1418  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1419  * currently support only one partition.
1420  */
1421 static int idetape_rewind_tape(ide_drive_t *drive)
1422 {
1423         struct ide_tape_obj *tape = drive->driver_data;
1424         struct gendisk *disk = tape->disk;
1425         int retval;
1426         struct ide_atapi_pc pc;
1427
1428         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1429
1430         idetape_create_rewind_cmd(drive, &pc);
1431         retval = ide_queue_pc_tail(drive, disk, &pc);
1432         if (retval)
1433                 return retval;
1434
1435         idetape_create_read_position_cmd(&pc);
1436         retval = ide_queue_pc_tail(drive, disk, &pc);
1437         if (retval)
1438                 return retval;
1439         return 0;
1440 }
1441
1442 /* mtio.h compatible commands should be issued to the chrdev interface. */
1443 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1444                                 unsigned long arg)
1445 {
1446         idetape_tape_t *tape = drive->driver_data;
1447         void __user *argp = (void __user *)arg;
1448
1449         struct idetape_config {
1450                 int dsc_rw_frequency;
1451                 int dsc_media_access_frequency;
1452                 int nr_stages;
1453         } config;
1454
1455         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1456
1457         switch (cmd) {
1458         case 0x0340:
1459                 if (copy_from_user(&config, argp, sizeof(config)))
1460                         return -EFAULT;
1461                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1462                 break;
1463         case 0x0350:
1464                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1465                 config.nr_stages = 1;
1466                 if (copy_to_user(argp, &config, sizeof(config)))
1467                         return -EFAULT;
1468                 break;
1469         default:
1470                 return -EIO;
1471         }
1472         return 0;
1473 }
1474
1475 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1476                                         int mt_count)
1477 {
1478         idetape_tape_t *tape = drive->driver_data;
1479         struct gendisk *disk = tape->disk;
1480         struct ide_atapi_pc pc;
1481         int retval, count = 0;
1482         int sprev = !!(tape->caps[4] & 0x20);
1483
1484         if (mt_count == 0)
1485                 return 0;
1486         if (MTBSF == mt_op || MTBSFM == mt_op) {
1487                 if (!sprev)
1488                         return -EIO;
1489                 mt_count = -mt_count;
1490         }
1491
1492         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1493                 tape->merge_bh_size = 0;
1494                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1495                         ++count;
1496                 ide_tape_discard_merge_buffer(drive, 0);
1497         }
1498
1499         switch (mt_op) {
1500         case MTFSF:
1501         case MTBSF:
1502                 idetape_create_space_cmd(&pc, mt_count - count,
1503                                          IDETAPE_SPACE_OVER_FILEMARK);
1504                 return ide_queue_pc_tail(drive, disk, &pc);
1505         case MTFSFM:
1506         case MTBSFM:
1507                 if (!sprev)
1508                         return -EIO;
1509                 retval = idetape_space_over_filemarks(drive, MTFSF,
1510                                                       mt_count - count);
1511                 if (retval)
1512                         return retval;
1513                 count = (MTBSFM == mt_op ? 1 : -1);
1514                 return idetape_space_over_filemarks(drive, MTFSF, count);
1515         default:
1516                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1517                                 mt_op);
1518                 return -EIO;
1519         }
1520 }
1521
1522 /*
1523  * Our character device read / write functions.
1524  *
1525  * The tape is optimized to maximize throughput when it is transferring an
1526  * integral number of the "continuous transfer limit", which is a parameter of
1527  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1528  *
1529  * As of version 1.3 of the driver, the character device provides an abstract
1530  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1531  * same backup/restore procedure is supported. The driver will internally
1532  * convert the requests to the recommended transfer unit, so that an unmatch
1533  * between the user's block size to the recommended size will only result in a
1534  * (slightly) increased driver overhead, but will no longer hit performance.
1535  * This is not applicable to Onstream.
1536  */
1537 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1538                                    size_t count, loff_t *ppos)
1539 {
1540         struct ide_tape_obj *tape = file->private_data;
1541         ide_drive_t *drive = tape->drive;
1542         ssize_t bytes_read, temp, actually_read = 0, rc;
1543         ssize_t ret = 0;
1544         u16 ctl = *(u16 *)&tape->caps[12];
1545
1546         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1547
1548         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1549                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1550                         if (count > tape->blk_size &&
1551                             (count % tape->blk_size) == 0)
1552                                 tape->user_bs_factor = count / tape->blk_size;
1553         }
1554         rc = idetape_init_read(drive);
1555         if (rc < 0)
1556                 return rc;
1557         if (count == 0)
1558                 return (0);
1559         if (tape->merge_bh_size) {
1560                 actually_read = min((unsigned int)(tape->merge_bh_size),
1561                                     (unsigned int)count);
1562                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1563                         ret = -EFAULT;
1564                 buf += actually_read;
1565                 tape->merge_bh_size -= actually_read;
1566                 count -= actually_read;
1567         }
1568         while (count >= tape->buffer_size) {
1569                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1570                 if (bytes_read <= 0)
1571                         goto finish;
1572                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1573                         ret = -EFAULT;
1574                 buf += bytes_read;
1575                 count -= bytes_read;
1576                 actually_read += bytes_read;
1577         }
1578         if (count) {
1579                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1580                 if (bytes_read <= 0)
1581                         goto finish;
1582                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1583                 if (idetape_copy_stage_to_user(tape, buf, temp))
1584                         ret = -EFAULT;
1585                 actually_read += temp;
1586                 tape->merge_bh_size = bytes_read-temp;
1587         }
1588 finish:
1589         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1590                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1591
1592                 idetape_space_over_filemarks(drive, MTFSF, 1);
1593                 return 0;
1594         }
1595
1596         return ret ? ret : actually_read;
1597 }
1598
1599 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1600                                      size_t count, loff_t *ppos)
1601 {
1602         struct ide_tape_obj *tape = file->private_data;
1603         ide_drive_t *drive = tape->drive;
1604         ssize_t actually_written = 0;
1605         ssize_t ret = 0;
1606         u16 ctl = *(u16 *)&tape->caps[12];
1607
1608         /* The drive is write protected. */
1609         if (tape->write_prot)
1610                 return -EACCES;
1611
1612         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1613
1614         /* Initialize write operation */
1615         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1616                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1617                         ide_tape_discard_merge_buffer(drive, 1);
1618                 if (tape->merge_bh || tape->merge_bh_size) {
1619                         printk(KERN_ERR "ide-tape: merge_bh_size "
1620                                 "should be 0 now\n");
1621                         tape->merge_bh_size = 0;
1622                 }
1623                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1624                 if (!tape->merge_bh)
1625                         return -ENOMEM;
1626                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1627                 idetape_init_merge_buffer(tape);
1628
1629                 /*
1630                  * Issue a write 0 command to ensure that DSC handshake is
1631                  * switched from completion mode to buffer available mode. No
1632                  * point in issuing this if DSC overlap isn't supported, some
1633                  * drives (Seagate STT3401A) will return an error.
1634                  */
1635                 if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
1636                         ssize_t retval = idetape_queue_rw_tail(drive,
1637                                                         REQ_IDETAPE_WRITE, 0,
1638                                                         tape->merge_bh);
1639                         if (retval < 0) {
1640                                 ide_tape_kfree_buffer(tape);
1641                                 tape->merge_bh = NULL;
1642                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1643                                 return retval;
1644                         }
1645                 }
1646         }
1647         if (count == 0)
1648                 return (0);
1649         if (tape->merge_bh_size) {
1650                 if (tape->merge_bh_size >= tape->buffer_size) {
1651                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1652                         tape->merge_bh_size = 0;
1653                 }
1654                 actually_written = min((unsigned int)
1655                                 (tape->buffer_size - tape->merge_bh_size),
1656                                 (unsigned int)count);
1657                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1658                                 ret = -EFAULT;
1659                 buf += actually_written;
1660                 tape->merge_bh_size += actually_written;
1661                 count -= actually_written;
1662
1663                 if (tape->merge_bh_size == tape->buffer_size) {
1664                         ssize_t retval;
1665                         tape->merge_bh_size = 0;
1666                         retval = idetape_add_chrdev_write_request(drive, ctl);
1667                         if (retval <= 0)
1668                                 return (retval);
1669                 }
1670         }
1671         while (count >= tape->buffer_size) {
1672                 ssize_t retval;
1673                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1674                         ret = -EFAULT;
1675                 buf += tape->buffer_size;
1676                 count -= tape->buffer_size;
1677                 retval = idetape_add_chrdev_write_request(drive, ctl);
1678                 actually_written += tape->buffer_size;
1679                 if (retval <= 0)
1680                         return (retval);
1681         }
1682         if (count) {
1683                 actually_written += count;
1684                 if (idetape_copy_stage_from_user(tape, buf, count))
1685                         ret = -EFAULT;
1686                 tape->merge_bh_size += count;
1687         }
1688         return ret ? ret : actually_written;
1689 }
1690
1691 static int idetape_write_filemark(ide_drive_t *drive)
1692 {
1693         struct ide_tape_obj *tape = drive->driver_data;
1694         struct ide_atapi_pc pc;
1695
1696         /* Write a filemark */
1697         idetape_create_write_filemark_cmd(drive, &pc, 1);
1698         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1699                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1700                 return -EIO;
1701         }
1702         return 0;
1703 }
1704
1705 /*
1706  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1707  * requested.
1708  *
1709  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1710  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1711  * usually not supported.
1712  *
1713  * The following commands are currently not supported:
1714  *
1715  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1716  * MT_ST_WRITE_THRESHOLD.
1717  */
1718 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1719 {
1720         idetape_tape_t *tape = drive->driver_data;
1721         struct gendisk *disk = tape->disk;
1722         struct ide_atapi_pc pc;
1723         int i, retval;
1724
1725         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1726                         mt_op, mt_count);
1727
1728         switch (mt_op) {
1729         case MTFSF:
1730         case MTFSFM:
1731         case MTBSF:
1732         case MTBSFM:
1733                 if (!mt_count)
1734                         return 0;
1735                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1736         default:
1737                 break;
1738         }
1739
1740         switch (mt_op) {
1741         case MTWEOF:
1742                 if (tape->write_prot)
1743                         return -EACCES;
1744                 ide_tape_discard_merge_buffer(drive, 1);
1745                 for (i = 0; i < mt_count; i++) {
1746                         retval = idetape_write_filemark(drive);
1747                         if (retval)
1748                                 return retval;
1749                 }
1750                 return 0;
1751         case MTREW:
1752                 ide_tape_discard_merge_buffer(drive, 0);
1753                 if (idetape_rewind_tape(drive))
1754                         return -EIO;
1755                 return 0;
1756         case MTLOAD:
1757                 ide_tape_discard_merge_buffer(drive, 0);
1758                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1759         case MTUNLOAD:
1760         case MTOFFL:
1761                 /*
1762                  * If door is locked, attempt to unlock before
1763                  * attempting to eject.
1764                  */
1765                 if (tape->door_locked) {
1766                         if (!ide_set_media_lock(drive, disk, 0))
1767                                 tape->door_locked = DOOR_UNLOCKED;
1768                 }
1769                 ide_tape_discard_merge_buffer(drive, 0);
1770                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1771                 if (!retval)
1772                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1773                 return retval;
1774         case MTNOP:
1775                 ide_tape_discard_merge_buffer(drive, 0);
1776                 return idetape_flush_tape_buffers(drive);
1777         case MTRETEN:
1778                 ide_tape_discard_merge_buffer(drive, 0);
1779                 return ide_do_start_stop(drive, disk,
1780                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1781         case MTEOM:
1782                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1783                 return ide_queue_pc_tail(drive, disk, &pc);
1784         case MTERASE:
1785                 (void)idetape_rewind_tape(drive);
1786                 idetape_create_erase_cmd(&pc);
1787                 return ide_queue_pc_tail(drive, disk, &pc);
1788         case MTSETBLK:
1789                 if (mt_count) {
1790                         if (mt_count < tape->blk_size ||
1791                             mt_count % tape->blk_size)
1792                                 return -EIO;
1793                         tape->user_bs_factor = mt_count / tape->blk_size;
1794                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1795                 } else
1796                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1797                 return 0;
1798         case MTSEEK:
1799                 ide_tape_discard_merge_buffer(drive, 0);
1800                 return idetape_position_tape(drive,
1801                         mt_count * tape->user_bs_factor, tape->partition, 0);
1802         case MTSETPART:
1803                 ide_tape_discard_merge_buffer(drive, 0);
1804                 return idetape_position_tape(drive, 0, mt_count, 0);
1805         case MTFSR:
1806         case MTBSR:
1807         case MTLOCK:
1808                 retval = ide_set_media_lock(drive, disk, 1);
1809                 if (retval)
1810                         return retval;
1811                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1812                 return 0;
1813         case MTUNLOCK:
1814                 retval = ide_set_media_lock(drive, disk, 0);
1815                 if (retval)
1816                         return retval;
1817                 tape->door_locked = DOOR_UNLOCKED;
1818                 return 0;
1819         default:
1820                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1821                                 mt_op);
1822                 return -EIO;
1823         }
1824 }
1825
1826 /*
1827  * Our character device ioctls. General mtio.h magnetic io commands are
1828  * supported here, and not in the corresponding block interface. Our own
1829  * ide-tape ioctls are supported on both interfaces.
1830  */
1831 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1832                                 unsigned int cmd, unsigned long arg)
1833 {
1834         struct ide_tape_obj *tape = file->private_data;
1835         ide_drive_t *drive = tape->drive;
1836         struct mtop mtop;
1837         struct mtget mtget;
1838         struct mtpos mtpos;
1839         int block_offset = 0, position = tape->first_frame;
1840         void __user *argp = (void __user *)arg;
1841
1842         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1843
1844         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1845                 ide_tape_flush_merge_buffer(drive);
1846                 idetape_flush_tape_buffers(drive);
1847         }
1848         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1849                 block_offset = tape->merge_bh_size /
1850                         (tape->blk_size * tape->user_bs_factor);
1851                 position = idetape_read_position(drive);
1852                 if (position < 0)
1853                         return -EIO;
1854         }
1855         switch (cmd) {
1856         case MTIOCTOP:
1857                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1858                         return -EFAULT;
1859                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1860         case MTIOCGET:
1861                 memset(&mtget, 0, sizeof(struct mtget));
1862                 mtget.mt_type = MT_ISSCSI2;
1863                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1864                 mtget.mt_dsreg =
1865                         ((tape->blk_size * tape->user_bs_factor)
1866                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1867
1868                 if (tape->drv_write_prot)
1869                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1870
1871                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1872                         return -EFAULT;
1873                 return 0;
1874         case MTIOCPOS:
1875                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1876                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1877                         return -EFAULT;
1878                 return 0;
1879         default:
1880                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1881                         ide_tape_discard_merge_buffer(drive, 1);
1882                 return idetape_blkdev_ioctl(drive, cmd, arg);
1883         }
1884 }
1885
1886 /*
1887  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1888  * block size with the reported value.
1889  */
1890 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1891 {
1892         idetape_tape_t *tape = drive->driver_data;
1893         struct ide_atapi_pc pc;
1894
1895         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1896         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1897                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1898                 if (tape->blk_size == 0) {
1899                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1900                                             "block size, assuming 32k\n");
1901                         tape->blk_size = 32768;
1902                 }
1903                 return;
1904         }
1905         tape->blk_size = (pc.buf[4 + 5] << 16) +
1906                                 (pc.buf[4 + 6] << 8)  +
1907                                  pc.buf[4 + 7];
1908         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1909 }
1910
1911 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1912 {
1913         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1914         ide_drive_t *drive;
1915         idetape_tape_t *tape;
1916         int retval;
1917
1918         if (i >= MAX_HWIFS * MAX_DRIVES)
1919                 return -ENXIO;
1920
1921         lock_kernel();
1922         tape = ide_tape_chrdev_get(i);
1923         if (!tape) {
1924                 unlock_kernel();
1925                 return -ENXIO;
1926         }
1927
1928         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1929
1930         /*
1931          * We really want to do nonseekable_open(inode, filp); here, but some
1932          * versions of tar incorrectly call lseek on tapes and bail out if that
1933          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1934          */
1935         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1936
1937         drive = tape->drive;
1938
1939         filp->private_data = tape;
1940
1941         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1942                 retval = -EBUSY;
1943                 goto out_put_tape;
1944         }
1945
1946         retval = idetape_wait_ready(drive, 60 * HZ);
1947         if (retval) {
1948                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1949                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1950                 goto out_put_tape;
1951         }
1952
1953         idetape_read_position(drive);
1954         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1955                 (void)idetape_rewind_tape(drive);
1956
1957         /* Read block size and write protect status from drive. */
1958         ide_tape_get_bsize_from_bdesc(drive);
1959
1960         /* Set write protect flag if device is opened as read-only. */
1961         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1962                 tape->write_prot = 1;
1963         else
1964                 tape->write_prot = tape->drv_write_prot;
1965
1966         /* Make sure drive isn't write protected if user wants to write. */
1967         if (tape->write_prot) {
1968                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1969                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1970                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1971                         retval = -EROFS;
1972                         goto out_put_tape;
1973                 }
1974         }
1975
1976         /* Lock the tape drive door so user can't eject. */
1977         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1978                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1979                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1980                                 tape->door_locked = DOOR_LOCKED;
1981                 }
1982         }
1983         unlock_kernel();
1984         return 0;
1985
1986 out_put_tape:
1987         ide_tape_put(tape);
1988         unlock_kernel();
1989         return retval;
1990 }
1991
1992 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
1993 {
1994         idetape_tape_t *tape = drive->driver_data;
1995
1996         ide_tape_flush_merge_buffer(drive);
1997         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
1998         if (tape->merge_bh != NULL) {
1999                 idetape_pad_zeros(drive, tape->blk_size *
2000                                 (tape->user_bs_factor - 1));
2001                 ide_tape_kfree_buffer(tape);
2002                 tape->merge_bh = NULL;
2003         }
2004         idetape_write_filemark(drive);
2005         idetape_flush_tape_buffers(drive);
2006         idetape_flush_tape_buffers(drive);
2007 }
2008
2009 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2010 {
2011         struct ide_tape_obj *tape = filp->private_data;
2012         ide_drive_t *drive = tape->drive;
2013         unsigned int minor = iminor(inode);
2014
2015         lock_kernel();
2016         tape = drive->driver_data;
2017
2018         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2019
2020         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2021                 idetape_write_release(drive, minor);
2022         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2023                 if (minor < 128)
2024                         ide_tape_discard_merge_buffer(drive, 1);
2025         }
2026
2027         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2028                 (void) idetape_rewind_tape(drive);
2029         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2030                 if (tape->door_locked == DOOR_LOCKED) {
2031                         if (!ide_set_media_lock(drive, tape->disk, 0))
2032                                 tape->door_locked = DOOR_UNLOCKED;
2033                 }
2034         }
2035         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2036         ide_tape_put(tape);
2037         unlock_kernel();
2038         return 0;
2039 }
2040
2041 static void idetape_get_inquiry_results(ide_drive_t *drive)
2042 {
2043         idetape_tape_t *tape = drive->driver_data;
2044         struct ide_atapi_pc pc;
2045         char fw_rev[4], vendor_id[8], product_id[16];
2046
2047         idetape_create_inquiry_cmd(&pc);
2048         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2049                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2050                                 tape->name);
2051                 return;
2052         }
2053         memcpy(vendor_id, &pc.buf[8], 8);
2054         memcpy(product_id, &pc.buf[16], 16);
2055         memcpy(fw_rev, &pc.buf[32], 4);
2056
2057         ide_fixstring(vendor_id, 8, 0);
2058         ide_fixstring(product_id, 16, 0);
2059         ide_fixstring(fw_rev, 4, 0);
2060
2061         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2062                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2063 }
2064
2065 /*
2066  * Ask the tape about its various parameters. In particular, we will adjust our
2067  * data transfer buffer size to the recommended value as returned by the tape.
2068  */
2069 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2070 {
2071         idetape_tape_t *tape = drive->driver_data;
2072         struct ide_atapi_pc pc;
2073         u8 *caps;
2074         u8 speed, max_speed;
2075
2076         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2077         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2078                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2079                                 " some default values\n");
2080                 tape->blk_size = 512;
2081                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2082                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2083                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2084                 return;
2085         }
2086         caps = pc.buf + 4 + pc.buf[3];
2087
2088         /* convert to host order and save for later use */
2089         speed = be16_to_cpup((__be16 *)&caps[14]);
2090         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2091
2092         *(u16 *)&caps[8] = max_speed;
2093         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2094         *(u16 *)&caps[14] = speed;
2095         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2096
2097         if (!speed) {
2098                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2099                                 "(assuming 650KB/sec)\n", drive->name);
2100                 *(u16 *)&caps[14] = 650;
2101         }
2102         if (!max_speed) {
2103                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2104                                 "(assuming 650KB/sec)\n", drive->name);
2105                 *(u16 *)&caps[8] = 650;
2106         }
2107
2108         memcpy(&tape->caps, caps, 20);
2109
2110         /* device lacks locking support according to capabilities page */
2111         if ((caps[6] & 1) == 0)
2112                 drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;
2113
2114         if (caps[7] & 0x02)
2115                 tape->blk_size = 512;
2116         else if (caps[7] & 0x04)
2117                 tape->blk_size = 1024;
2118 }
2119
2120 #ifdef CONFIG_IDE_PROC_FS
2121 #define ide_tape_devset_get(name, field) \
2122 static int get_##name(ide_drive_t *drive) \
2123 { \
2124         idetape_tape_t *tape = drive->driver_data; \
2125         return tape->field; \
2126 }
2127
2128 #define ide_tape_devset_set(name, field) \
2129 static int set_##name(ide_drive_t *drive, int arg) \
2130 { \
2131         idetape_tape_t *tape = drive->driver_data; \
2132         tape->field = arg; \
2133         return 0; \
2134 }
2135
2136 #define ide_tape_devset_rw_field(_name, _field) \
2137 ide_tape_devset_get(_name, _field) \
2138 ide_tape_devset_set(_name, _field) \
2139 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2140
2141 #define ide_tape_devset_r_field(_name, _field) \
2142 ide_tape_devset_get(_name, _field) \
2143 IDE_DEVSET(_name, 0, get_##_name, NULL)
2144
2145 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2146 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2147 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2148 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2149
2150 ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);
2151
2152 ide_tape_devset_rw_field(debug_mask, debug_mask);
2153 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2154
2155 ide_tape_devset_r_field(avg_speed, avg_speed);
2156 ide_tape_devset_r_field(speed, caps[14]);
2157 ide_tape_devset_r_field(buffer, caps[16]);
2158 ide_tape_devset_r_field(buffer_size, buffer_size);
2159
2160 static const struct ide_proc_devset idetape_settings[] = {
2161         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2162         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2163         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2164         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2165         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2166         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2167         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2168                                         mulf_tdsc, divf_tdsc),
2169         { NULL },
2170 };
2171 #endif
2172
2173 /*
2174  * The function below is called to:
2175  *
2176  * 1. Initialize our various state variables.
2177  * 2. Ask the tape for its capabilities.
2178  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2179  * is chosen based on the recommendation which we received in step 2.
2180  *
2181  * Note that at this point ide.c already assigned us an irq, so that we can
2182  * queue requests here and wait for their completion.
2183  */
2184 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2185 {
2186         unsigned long t;
2187         int speed;
2188         int buffer_size;
2189         u16 *ctl = (u16 *)&tape->caps[12];
2190
2191         drive->pc_callback       = ide_tape_callback;
2192         drive->pc_update_buffers = idetape_update_buffers;
2193         drive->pc_io_buffers     = ide_tape_io_buffers;
2194
2195         spin_lock_init(&tape->lock);
2196
2197         drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
2198
2199         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2200                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2201                                  tape->name);
2202                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2203         }
2204
2205         /* Seagate Travan drives do not support DSC overlap. */
2206         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2207                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2208
2209         tape->minor = minor;
2210         tape->name[0] = 'h';
2211         tape->name[1] = 't';
2212         tape->name[2] = '0' + minor;
2213         tape->chrdev_dir = IDETAPE_DIR_NONE;
2214
2215         idetape_get_inquiry_results(drive);
2216         idetape_get_mode_sense_results(drive);
2217         ide_tape_get_bsize_from_bdesc(drive);
2218         tape->user_bs_factor = 1;
2219         tape->buffer_size = *ctl * tape->blk_size;
2220         while (tape->buffer_size > 0xffff) {
2221                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2222                 *ctl /= 2;
2223                 tape->buffer_size = *ctl * tape->blk_size;
2224         }
2225         buffer_size = tape->buffer_size;
2226         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2227         if (buffer_size % PAGE_SIZE) {
2228                 tape->pages_per_buffer++;
2229                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2230         }
2231
2232         /* select the "best" DSC read/write polling freq */
2233         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2234
2235         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2236
2237         /*
2238          * Ensure that the number we got makes sense; limit it within
2239          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2240          */
2241         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2242                                          IDETAPE_DSC_RW_MAX);
2243         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2244                 "%lums tDSC%s\n",
2245                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2246                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2247                 tape->buffer_size / 1024,
2248                 tape->best_dsc_rw_freq * 1000 / HZ,
2249                 (drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");
2250
2251         ide_proc_register_driver(drive, tape->driver);
2252 }
2253
2254 static void ide_tape_remove(ide_drive_t *drive)
2255 {
2256         idetape_tape_t *tape = drive->driver_data;
2257
2258         ide_proc_unregister_driver(drive, tape->driver);
2259         device_del(&tape->dev);
2260         ide_unregister_region(tape->disk);
2261
2262         mutex_lock(&idetape_ref_mutex);
2263         put_device(&tape->dev);
2264         mutex_unlock(&idetape_ref_mutex);
2265 }
2266
2267 static void ide_tape_release(struct device *dev)
2268 {
2269         struct ide_tape_obj *tape = to_ide_drv(dev, ide_tape_obj);
2270         ide_drive_t *drive = tape->drive;
2271         struct gendisk *g = tape->disk;
2272
2273         BUG_ON(tape->merge_bh_size);
2274
2275         drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
2276         drive->driver_data = NULL;
2277         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2278         device_destroy(idetape_sysfs_class,
2279                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2280         idetape_devs[tape->minor] = NULL;
2281         g->private_data = NULL;
2282         put_disk(g);
2283         kfree(tape);
2284 }
2285
2286 #ifdef CONFIG_IDE_PROC_FS
2287 static int proc_idetape_read_name
2288         (char *page, char **start, off_t off, int count, int *eof, void *data)
2289 {
2290         ide_drive_t     *drive = (ide_drive_t *) data;
2291         idetape_tape_t  *tape = drive->driver_data;
2292         char            *out = page;
2293         int             len;
2294
2295         len = sprintf(out, "%s\n", tape->name);
2296         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2297 }
2298
2299 static ide_proc_entry_t idetape_proc[] = {
2300         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2301         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2302         { NULL, 0, NULL, NULL }
2303 };
2304
2305 static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive)
2306 {
2307         return idetape_proc;
2308 }
2309
2310 static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive)
2311 {
2312         return idetape_settings;
2313 }
2314 #endif
2315
2316 static int ide_tape_probe(ide_drive_t *);
2317
2318 static struct ide_driver idetape_driver = {
2319         .gen_driver = {
2320                 .owner          = THIS_MODULE,
2321                 .name           = "ide-tape",
2322                 .bus            = &ide_bus_type,
2323         },
2324         .probe                  = ide_tape_probe,
2325         .remove                 = ide_tape_remove,
2326         .version                = IDETAPE_VERSION,
2327         .do_request             = idetape_do_request,
2328         .end_request            = idetape_end_request,
2329 #ifdef CONFIG_IDE_PROC_FS
2330         .proc_entries           = ide_tape_proc_entries,
2331         .proc_devsets           = ide_tape_proc_devsets,
2332 #endif
2333 };
2334
2335 /* Our character device supporting functions, passed to register_chrdev. */
2336 static const struct file_operations idetape_fops = {
2337         .owner          = THIS_MODULE,
2338         .read           = idetape_chrdev_read,
2339         .write          = idetape_chrdev_write,
2340         .ioctl          = idetape_chrdev_ioctl,
2341         .open           = idetape_chrdev_open,
2342         .release        = idetape_chrdev_release,
2343 };
2344
2345 static int idetape_open(struct block_device *bdev, fmode_t mode)
2346 {
2347         struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk);
2348
2349         if (!tape)
2350                 return -ENXIO;
2351
2352         return 0;
2353 }
2354
2355 static int idetape_release(struct gendisk *disk, fmode_t mode)
2356 {
2357         struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
2358
2359         ide_tape_put(tape);
2360         return 0;
2361 }
2362
2363 static int idetape_ioctl(struct block_device *bdev, fmode_t mode,
2364                         unsigned int cmd, unsigned long arg)
2365 {
2366         struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
2367         ide_drive_t *drive = tape->drive;
2368         int err = generic_ide_ioctl(drive, bdev, cmd, arg);
2369         if (err == -EINVAL)
2370                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2371         return err;
2372 }
2373
2374 static struct block_device_operations idetape_block_ops = {
2375         .owner          = THIS_MODULE,
2376         .open           = idetape_open,
2377         .release        = idetape_release,
2378         .locked_ioctl   = idetape_ioctl,
2379 };
2380
2381 static int ide_tape_probe(ide_drive_t *drive)
2382 {
2383         idetape_tape_t *tape;
2384         struct gendisk *g;
2385         int minor;
2386
2387         if (!strstr("ide-tape", drive->driver_req))
2388                 goto failed;
2389
2390         if (drive->media != ide_tape)
2391                 goto failed;
2392
2393         if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&
2394             ide_check_atapi_device(drive, DRV_NAME) == 0) {
2395                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2396                                 " the driver\n", drive->name);
2397                 goto failed;
2398         }
2399         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2400         if (tape == NULL) {
2401                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2402                                 drive->name);
2403                 goto failed;
2404         }
2405
2406         g = alloc_disk(1 << PARTN_BITS);
2407         if (!g)
2408                 goto out_free_tape;
2409
2410         ide_init_disk(g, drive);
2411
2412         tape->dev.parent = &drive->gendev;
2413         tape->dev.release = ide_tape_release;
2414         dev_set_name(&tape->dev, dev_name(&drive->gendev));
2415
2416         if (device_register(&tape->dev))
2417                 goto out_free_disk;
2418
2419         tape->drive = drive;
2420         tape->driver = &idetape_driver;
2421         tape->disk = g;
2422
2423         g->private_data = &tape->driver;
2424
2425         drive->driver_data = tape;
2426
2427         mutex_lock(&idetape_ref_mutex);
2428         for (minor = 0; idetape_devs[minor]; minor++)
2429                 ;
2430         idetape_devs[minor] = tape;
2431         mutex_unlock(&idetape_ref_mutex);
2432
2433         idetape_setup(drive, tape, minor);
2434
2435         device_create(idetape_sysfs_class, &drive->gendev,
2436                       MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);
2437         device_create(idetape_sysfs_class, &drive->gendev,
2438                       MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2439                       "n%s", tape->name);
2440
2441         g->fops = &idetape_block_ops;
2442         ide_register_region(g);
2443
2444         return 0;
2445
2446 out_free_disk:
2447         put_disk(g);
2448 out_free_tape:
2449         kfree(tape);
2450 failed:
2451         return -ENODEV;
2452 }
2453
2454 static void __exit idetape_exit(void)
2455 {
2456         driver_unregister(&idetape_driver.gen_driver);
2457         class_destroy(idetape_sysfs_class);
2458         unregister_chrdev(IDETAPE_MAJOR, "ht");
2459 }
2460
2461 static int __init idetape_init(void)
2462 {
2463         int error = 1;
2464         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2465         if (IS_ERR(idetape_sysfs_class)) {
2466                 idetape_sysfs_class = NULL;
2467                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2468                 error = -EBUSY;
2469                 goto out;
2470         }
2471
2472         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2473                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2474                                 " interface\n");
2475                 error = -EBUSY;
2476                 goto out_free_class;
2477         }
2478
2479         error = driver_register(&idetape_driver.gen_driver);
2480         if (error)
2481                 goto out_free_driver;
2482
2483         return 0;
2484
2485 out_free_driver:
2486         driver_unregister(&idetape_driver.gen_driver);
2487 out_free_class:
2488         class_destroy(idetape_sysfs_class);
2489 out:
2490         return error;
2491 }
2492
2493 MODULE_ALIAS("ide:*m-tape*");
2494 module_init(idetape_init);
2495 module_exit(idetape_exit);
2496 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2497 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2498 MODULE_LICENSE("GPL");