5c26e98e2e396c70a63a982d3db6e7d10b95e0d8
[linux-2.6.git] / drivers / ide / ide-tape.c
1 /*
2  * IDE ATAPI streaming tape driver.
3  *
4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
6  *
7  * This driver was constructed as a student project in the software laboratory
8  * of the faculty of electrical engineering in the Technion - Israel's
9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
10  *
11  * It is hereby placed under the terms of the GNU general public license.
12  * (See linux/COPYING).
13  *
14  * For a historical changelog see
15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
16  */
17
18 #define DRV_NAME "ide-tape"
19
20 #define IDETAPE_VERSION "1.20"
21
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/kernel.h>
26 #include <linux/delay.h>
27 #include <linux/timer.h>
28 #include <linux/mm.h>
29 #include <linux/interrupt.h>
30 #include <linux/jiffies.h>
31 #include <linux/major.h>
32 #include <linux/errno.h>
33 #include <linux/genhd.h>
34 #include <linux/slab.h>
35 #include <linux/pci.h>
36 #include <linux/ide.h>
37 #include <linux/smp_lock.h>
38 #include <linux/completion.h>
39 #include <linux/bitops.h>
40 #include <linux/mutex.h>
41 #include <scsi/scsi.h>
42
43 #include <asm/byteorder.h>
44 #include <linux/irq.h>
45 #include <linux/uaccess.h>
46 #include <linux/io.h>
47 #include <asm/unaligned.h>
48 #include <linux/mtio.h>
49
50 enum {
51         /* output errors only */
52         DBG_ERR =               (1 << 0),
53         /* output all sense key/asc */
54         DBG_SENSE =             (1 << 1),
55         /* info regarding all chrdev-related procedures */
56         DBG_CHRDEV =            (1 << 2),
57         /* all remaining procedures */
58         DBG_PROCS =             (1 << 3),
59 };
60
61 /* define to see debug info */
62 #define IDETAPE_DEBUG_LOG               0
63
64 #if IDETAPE_DEBUG_LOG
65 #define debug_log(lvl, fmt, args...)                    \
66 {                                                       \
67         if (tape->debug_mask & lvl)                     \
68         printk(KERN_INFO "ide-tape: " fmt, ## args);    \
69 }
70 #else
71 #define debug_log(lvl, fmt, args...) do {} while (0)
72 #endif
73
74 /**************************** Tunable parameters *****************************/
75 /*
76  * After each failed packet command we issue a request sense command and retry
77  * the packet command IDETAPE_MAX_PC_RETRIES times.
78  *
79  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
80  */
81 #define IDETAPE_MAX_PC_RETRIES          3
82
83 /*
84  * The following parameter is used to select the point in the internal tape fifo
85  * in which we will start to refill the buffer. Decreasing the following
86  * parameter will improve the system's latency and interactive response, while
87  * using a high value might improve system throughput.
88  */
89 #define IDETAPE_FIFO_THRESHOLD          2
90
91 /*
92  * DSC polling parameters.
93  *
94  * Polling for DSC (a single bit in the status register) is a very important
95  * function in ide-tape. There are two cases in which we poll for DSC:
96  *
97  * 1. Before a read/write packet command, to ensure that we can transfer data
98  * from/to the tape's data buffers, without causing an actual media access.
99  * In case the tape is not ready yet, we take out our request from the device
100  * request queue, so that ide.c could service requests from the other device
101  * on the same interface in the meantime.
102  *
103  * 2. After the successful initialization of a "media access packet command",
104  * which is a command that can take a long time to complete (the interval can
105  * range from several seconds to even an hour). Again, we postpone our request
106  * in the middle to free the bus for the other device. The polling frequency
107  * here should be lower than the read/write frequency since those media access
108  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
109  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
110  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
111  *
112  * We also set a timeout for the timer, in case something goes wrong. The
113  * timeout should be longer then the maximum execution time of a tape operation.
114  */
115
116 /* DSC timings. */
117 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
118 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
119 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
120 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
121 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
122 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
123 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
124
125 /*************************** End of tunable parameters ***********************/
126
127 /* tape directions */
128 enum {
129         IDETAPE_DIR_NONE  = (1 << 0),
130         IDETAPE_DIR_READ  = (1 << 1),
131         IDETAPE_DIR_WRITE = (1 << 2),
132 };
133
134 struct idetape_bh {
135         u32 b_size;
136         atomic_t b_count;
137         struct idetape_bh *b_reqnext;
138         char *b_data;
139 };
140
141 /* Tape door status */
142 #define DOOR_UNLOCKED                   0
143 #define DOOR_LOCKED                     1
144 #define DOOR_EXPLICITLY_LOCKED          2
145
146 /* Some defines for the SPACE command */
147 #define IDETAPE_SPACE_OVER_FILEMARK     1
148 #define IDETAPE_SPACE_TO_EOD            3
149
150 /* Some defines for the LOAD UNLOAD command */
151 #define IDETAPE_LU_LOAD_MASK            1
152 #define IDETAPE_LU_RETENSION_MASK       2
153 #define IDETAPE_LU_EOT_MASK             4
154
155 /* Error codes returned in rq->errors to the higher part of the driver. */
156 #define IDETAPE_ERROR_GENERAL           101
157 #define IDETAPE_ERROR_FILEMARK          102
158 #define IDETAPE_ERROR_EOD               103
159
160 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
161 #define IDETAPE_BLOCK_DESCRIPTOR        0
162 #define IDETAPE_CAPABILITIES_PAGE       0x2a
163
164 /*
165  * Most of our global data which we need to save even as we leave the driver due
166  * to an interrupt or a timer event is stored in the struct defined below.
167  */
168 typedef struct ide_tape_obj {
169         ide_drive_t     *drive;
170         ide_driver_t    *driver;
171         struct gendisk  *disk;
172         struct kref     kref;
173
174         /*
175          *      failed_pc points to the last failed packet command, or contains
176          *      NULL if we do not need to retry any packet command. This is
177          *      required since an additional packet command is needed before the
178          *      retry, to get detailed information on what went wrong.
179          */
180         /* Last failed packet command */
181         struct ide_atapi_pc *failed_pc;
182         /* used by REQ_IDETAPE_{READ,WRITE} requests */
183         struct ide_atapi_pc queued_pc;
184
185         /*
186          * DSC polling variables.
187          *
188          * While polling for DSC we use postponed_rq to postpone the current
189          * request so that ide.c will be able to service pending requests on the
190          * other device. Note that at most we will have only one DSC (usually
191          * data transfer) request in the device request queue.
192          */
193         struct request *postponed_rq;
194         /* The time in which we started polling for DSC */
195         unsigned long dsc_polling_start;
196         /* Timer used to poll for dsc */
197         struct timer_list dsc_timer;
198         /* Read/Write dsc polling frequency */
199         unsigned long best_dsc_rw_freq;
200         unsigned long dsc_poll_freq;
201         unsigned long dsc_timeout;
202
203         /* Read position information */
204         u8 partition;
205         /* Current block */
206         unsigned int first_frame;
207
208         /* Last error information */
209         u8 sense_key, asc, ascq;
210
211         /* Character device operation */
212         unsigned int minor;
213         /* device name */
214         char name[4];
215         /* Current character device data transfer direction */
216         u8 chrdev_dir;
217
218         /* tape block size, usually 512 or 1024 bytes */
219         unsigned short blk_size;
220         int user_bs_factor;
221
222         /* Copy of the tape's Capabilities and Mechanical Page */
223         u8 caps[20];
224
225         /*
226          * Active data transfer request parameters.
227          *
228          * At most, there is only one ide-tape originated data transfer request
229          * in the device request queue. This allows ide.c to easily service
230          * requests from the other device when we postpone our active request.
231          */
232
233         /* Data buffer size chosen based on the tape's recommendation */
234         int buffer_size;
235         /* merge buffer */
236         struct idetape_bh *merge_bh;
237         /* size of the merge buffer */
238         int merge_bh_size;
239         /* pointer to current buffer head within the merge buffer */
240         struct idetape_bh *bh;
241         char *b_data;
242         int b_count;
243
244         int pages_per_buffer;
245         /* Wasted space in each stage */
246         int excess_bh_size;
247
248         /* protects the ide-tape queue */
249         spinlock_t lock;
250
251         /* Measures average tape speed */
252         unsigned long avg_time;
253         int avg_size;
254         int avg_speed;
255
256         /* the door is currently locked */
257         int door_locked;
258         /* the tape hardware is write protected */
259         char drv_write_prot;
260         /* the tape is write protected (hardware or opened as read-only) */
261         char write_prot;
262
263         u32 debug_mask;
264 } idetape_tape_t;
265
266 static DEFINE_MUTEX(idetape_ref_mutex);
267
268 static struct class *idetape_sysfs_class;
269
270 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
271
272 #define ide_tape_g(disk) \
273         container_of((disk)->private_data, struct ide_tape_obj, driver)
274
275 static void ide_tape_release(struct kref *);
276
277 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
278 {
279         struct ide_tape_obj *tape = NULL;
280
281         mutex_lock(&idetape_ref_mutex);
282         tape = ide_tape_g(disk);
283         if (tape) {
284                 if (ide_device_get(tape->drive))
285                         tape = NULL;
286                 else
287                         kref_get(&tape->kref);
288         }
289         mutex_unlock(&idetape_ref_mutex);
290         return tape;
291 }
292
293 static void ide_tape_put(struct ide_tape_obj *tape)
294 {
295         ide_drive_t *drive = tape->drive;
296
297         mutex_lock(&idetape_ref_mutex);
298         kref_put(&tape->kref, ide_tape_release);
299         ide_device_put(drive);
300         mutex_unlock(&idetape_ref_mutex);
301 }
302
303 /*
304  * The variables below are used for the character device interface. Additional
305  * state variables are defined in our ide_drive_t structure.
306  */
307 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
308
309 #define ide_tape_f(file) ((file)->private_data)
310
311 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
312 {
313         struct ide_tape_obj *tape = NULL;
314
315         mutex_lock(&idetape_ref_mutex);
316         tape = idetape_devs[i];
317         if (tape)
318                 kref_get(&tape->kref);
319         mutex_unlock(&idetape_ref_mutex);
320         return tape;
321 }
322
323 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
324                                   unsigned int bcount)
325 {
326         struct idetape_bh *bh = pc->bh;
327         int count;
328
329         while (bcount) {
330                 if (bh == NULL) {
331                         printk(KERN_ERR "ide-tape: bh == NULL in "
332                                 "idetape_input_buffers\n");
333                         ide_pad_transfer(drive, 0, bcount);
334                         return;
335                 }
336                 count = min(
337                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
338                         bcount);
339                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
340                                         atomic_read(&bh->b_count), count);
341                 bcount -= count;
342                 atomic_add(count, &bh->b_count);
343                 if (atomic_read(&bh->b_count) == bh->b_size) {
344                         bh = bh->b_reqnext;
345                         if (bh)
346                                 atomic_set(&bh->b_count, 0);
347                 }
348         }
349         pc->bh = bh;
350 }
351
352 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
353                                    unsigned int bcount)
354 {
355         struct idetape_bh *bh = pc->bh;
356         int count;
357
358         while (bcount) {
359                 if (bh == NULL) {
360                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
361                                         __func__);
362                         return;
363                 }
364                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
365                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
366                 bcount -= count;
367                 pc->b_data += count;
368                 pc->b_count -= count;
369                 if (!pc->b_count) {
370                         bh = bh->b_reqnext;
371                         pc->bh = bh;
372                         if (bh) {
373                                 pc->b_data = bh->b_data;
374                                 pc->b_count = atomic_read(&bh->b_count);
375                         }
376                 }
377         }
378 }
379
380 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
381 {
382         struct idetape_bh *bh = pc->bh;
383         int count;
384         unsigned int bcount = pc->xferred;
385
386         if (pc->flags & PC_FLAG_WRITING)
387                 return;
388         while (bcount) {
389                 if (bh == NULL) {
390                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
391                                         __func__);
392                         return;
393                 }
394                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
395                 atomic_set(&bh->b_count, count);
396                 if (atomic_read(&bh->b_count) == bh->b_size)
397                         bh = bh->b_reqnext;
398                 bcount -= count;
399         }
400         pc->bh = bh;
401 }
402
403 /*
404  * called on each failed packet command retry to analyze the request sense. We
405  * currently do not utilize this information.
406  */
407 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
408 {
409         idetape_tape_t *tape = drive->driver_data;
410         struct ide_atapi_pc *pc = tape->failed_pc;
411
412         tape->sense_key = sense[2] & 0xF;
413         tape->asc       = sense[12];
414         tape->ascq      = sense[13];
415
416         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
417                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
418
419         /* Correct pc->xferred by asking the tape.       */
420         if (pc->flags & PC_FLAG_DMA_ERROR) {
421                 pc->xferred = pc->req_xfer -
422                         tape->blk_size *
423                         get_unaligned_be32(&sense[3]);
424                 idetape_update_buffers(drive, pc);
425         }
426
427         /*
428          * If error was the result of a zero-length read or write command,
429          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
430          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
431          */
432         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
433             /* length == 0 */
434             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
435                 if (tape->sense_key == 5) {
436                         /* don't report an error, everything's ok */
437                         pc->error = 0;
438                         /* don't retry read/write */
439                         pc->flags |= PC_FLAG_ABORT;
440                 }
441         }
442         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
443                 pc->error = IDETAPE_ERROR_FILEMARK;
444                 pc->flags |= PC_FLAG_ABORT;
445         }
446         if (pc->c[0] == WRITE_6) {
447                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
448                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
449                         pc->error = IDETAPE_ERROR_EOD;
450                         pc->flags |= PC_FLAG_ABORT;
451                 }
452         }
453         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
454                 if (tape->sense_key == 8) {
455                         pc->error = IDETAPE_ERROR_EOD;
456                         pc->flags |= PC_FLAG_ABORT;
457                 }
458                 if (!(pc->flags & PC_FLAG_ABORT) &&
459                     pc->xferred)
460                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
461         }
462 }
463
464 /* Free data buffers completely. */
465 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
466 {
467         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
468
469         while (bh) {
470                 u32 size = bh->b_size;
471
472                 while (size) {
473                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
474
475                         if (bh->b_data)
476                                 free_pages((unsigned long)bh->b_data, order);
477
478                         size &= (order-1);
479                         bh->b_data += (1 << order) * PAGE_SIZE;
480                 }
481                 prev_bh = bh;
482                 bh = bh->b_reqnext;
483                 kfree(prev_bh);
484         }
485 }
486
487 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
488 {
489         struct request *rq = HWGROUP(drive)->rq;
490         idetape_tape_t *tape = drive->driver_data;
491         unsigned long flags;
492         int error;
493
494         debug_log(DBG_PROCS, "Enter %s\n", __func__);
495
496         switch (uptodate) {
497         case 0: error = IDETAPE_ERROR_GENERAL; break;
498         case 1: error = 0; break;
499         default: error = uptodate;
500         }
501         rq->errors = error;
502         if (error)
503                 tape->failed_pc = NULL;
504
505         if (!blk_special_request(rq)) {
506                 ide_end_request(drive, uptodate, nr_sects);
507                 return 0;
508         }
509
510         spin_lock_irqsave(&tape->lock, flags);
511
512         ide_end_drive_cmd(drive, 0, 0);
513
514         spin_unlock_irqrestore(&tape->lock, flags);
515         return 0;
516 }
517
518 static void ide_tape_handle_dsc(ide_drive_t *);
519
520 static void ide_tape_callback(ide_drive_t *drive, int dsc)
521 {
522         idetape_tape_t *tape = drive->driver_data;
523         struct ide_atapi_pc *pc = drive->pc;
524         int uptodate = pc->error ? 0 : 1;
525
526         debug_log(DBG_PROCS, "Enter %s\n", __func__);
527
528         if (dsc)
529                 ide_tape_handle_dsc(drive);
530
531         if (tape->failed_pc == pc)
532                 tape->failed_pc = NULL;
533
534         if (pc->c[0] == REQUEST_SENSE) {
535                 if (uptodate)
536                         idetape_analyze_error(drive, pc->buf);
537                 else
538                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
539                                         "itself - Aborting request!\n");
540         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
541                 struct request *rq = drive->hwif->hwgroup->rq;
542                 int blocks = pc->xferred / tape->blk_size;
543
544                 tape->avg_size += blocks * tape->blk_size;
545
546                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
547                         tape->avg_speed = tape->avg_size * HZ /
548                                 (jiffies - tape->avg_time) / 1024;
549                         tape->avg_size = 0;
550                         tape->avg_time = jiffies;
551                 }
552
553                 tape->first_frame += blocks;
554                 rq->current_nr_sectors -= blocks;
555
556                 if (pc->error)
557                         uptodate = pc->error;
558         } else if (pc->c[0] == READ_POSITION && uptodate) {
559                 u8 *readpos = pc->buf;
560
561                 debug_log(DBG_SENSE, "BOP - %s\n",
562                                 (readpos[0] & 0x80) ? "Yes" : "No");
563                 debug_log(DBG_SENSE, "EOP - %s\n",
564                                 (readpos[0] & 0x40) ? "Yes" : "No");
565
566                 if (readpos[0] & 0x4) {
567                         printk(KERN_INFO "ide-tape: Block location is unknown"
568                                          "to the tape\n");
569                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
570                         uptodate = 0;
571                 } else {
572                         debug_log(DBG_SENSE, "Block Location - %u\n",
573                                         be32_to_cpup((__be32 *)&readpos[4]));
574
575                         tape->partition = readpos[1];
576                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
577                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
578                 }
579         }
580
581         idetape_end_request(drive, uptodate, 0);
582 }
583
584 /*
585  * Postpone the current request so that ide.c will be able to service requests
586  * from another device on the same hwgroup while we are polling for DSC.
587  */
588 static void idetape_postpone_request(ide_drive_t *drive)
589 {
590         idetape_tape_t *tape = drive->driver_data;
591
592         debug_log(DBG_PROCS, "Enter %s\n", __func__);
593
594         tape->postponed_rq = HWGROUP(drive)->rq;
595         ide_stall_queue(drive, tape->dsc_poll_freq);
596 }
597
598 static void ide_tape_handle_dsc(ide_drive_t *drive)
599 {
600         idetape_tape_t *tape = drive->driver_data;
601
602         /* Media access command */
603         tape->dsc_polling_start = jiffies;
604         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
605         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
606         /* Allow ide.c to handle other requests */
607         idetape_postpone_request(drive);
608 }
609
610 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
611                                 unsigned int bcount, int write)
612 {
613         if (write)
614                 idetape_output_buffers(drive, pc, bcount);
615         else
616                 idetape_input_buffers(drive, pc, bcount);
617
618         return bcount;
619 }
620
621 /*
622  * This is the usual interrupt handler which will be called during a packet
623  * command. We will transfer some of the data (as requested by the drive) and
624  * will re-point interrupt handler to us. When data transfer is finished, we
625  * will act according to the algorithm described before
626  * idetape_issue_pc.
627  */
628 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
629 {
630         return ide_pc_intr(drive, idetape_pc_intr);
631 }
632
633 /*
634  * Packet Command Interface
635  *
636  * The current Packet Command is available in drive->pc, and will not change
637  * until we finish handling it. Each packet command is associated with a
638  * callback function that will be called when the command is finished.
639  *
640  * The handling will be done in three stages:
641  *
642  * 1. idetape_issue_pc will send the packet command to the drive, and will set
643  * the interrupt handler to idetape_pc_intr.
644  *
645  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
646  * repeated until the device signals us that no more interrupts will be issued.
647  *
648  * 3. ATAPI Tape media access commands have immediate status with a delayed
649  * process. In case of a successful initiation of a media access packet command,
650  * the DSC bit will be set when the actual execution of the command is finished.
651  * Since the tape drive will not issue an interrupt, we have to poll for this
652  * event. In this case, we define the request as "low priority request" by
653  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
654  * exit the driver.
655  *
656  * ide.c will then give higher priority to requests which originate from the
657  * other device, until will change rq_status to RQ_ACTIVE.
658  *
659  * 4. When the packet command is finished, it will be checked for errors.
660  *
661  * 5. In case an error was found, we queue a request sense packet command in
662  * front of the request queue and retry the operation up to
663  * IDETAPE_MAX_PC_RETRIES times.
664  *
665  * 6. In case no error was found, or we decided to give up and not to retry
666  * again, the callback function will be called and then we will handle the next
667  * request.
668  */
669 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
670 {
671         return ide_transfer_pc(drive, idetape_pc_intr, WAIT_TAPE_CMD, NULL);
672 }
673
674 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
675                 struct ide_atapi_pc *pc)
676 {
677         idetape_tape_t *tape = drive->driver_data;
678
679         if (drive->pc->c[0] == REQUEST_SENSE &&
680             pc->c[0] == REQUEST_SENSE) {
681                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
682                         "Two request sense in serial were issued\n");
683         }
684
685         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
686                 tape->failed_pc = pc;
687
688         /* Set the current packet command */
689         drive->pc = pc;
690
691         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
692                 (pc->flags & PC_FLAG_ABORT)) {
693                 /*
694                  * We will "abort" retrying a packet command in case legitimate
695                  * error code was received (crossing a filemark, or end of the
696                  * media, for example).
697                  */
698                 if (!(pc->flags & PC_FLAG_ABORT)) {
699                         if (!(pc->c[0] == TEST_UNIT_READY &&
700                               tape->sense_key == 2 && tape->asc == 4 &&
701                              (tape->ascq == 1 || tape->ascq == 8))) {
702                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
703                                                 "pc = %2x, key = %2x, "
704                                                 "asc = %2x, ascq = %2x\n",
705                                                 tape->name, pc->c[0],
706                                                 tape->sense_key, tape->asc,
707                                                 tape->ascq);
708                         }
709                         /* Giving up */
710                         pc->error = IDETAPE_ERROR_GENERAL;
711                 }
712                 tape->failed_pc = NULL;
713                 drive->pc_callback(drive, 0);
714                 return ide_stopped;
715         }
716         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
717
718         pc->retries++;
719
720         return ide_issue_pc(drive, idetape_transfer_pc, WAIT_TAPE_CMD, NULL);
721 }
722
723 /* A mode sense command is used to "sense" tape parameters. */
724 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
725 {
726         ide_init_pc(pc);
727         pc->c[0] = MODE_SENSE;
728         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
729                 /* DBD = 1 - Don't return block descriptors */
730                 pc->c[1] = 8;
731         pc->c[2] = page_code;
732         /*
733          * Changed pc->c[3] to 0 (255 will at best return unused info).
734          *
735          * For SCSI this byte is defined as subpage instead of high byte
736          * of length and some IDE drives seem to interpret it this way
737          * and return an error when 255 is used.
738          */
739         pc->c[3] = 0;
740         /* We will just discard data in that case */
741         pc->c[4] = 255;
742         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
743                 pc->req_xfer = 12;
744         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
745                 pc->req_xfer = 24;
746         else
747                 pc->req_xfer = 50;
748 }
749
750 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
751 {
752         ide_hwif_t *hwif = drive->hwif;
753         idetape_tape_t *tape = drive->driver_data;
754         struct ide_atapi_pc *pc = drive->pc;
755         u8 stat;
756
757         stat = hwif->tp_ops->read_status(hwif);
758
759         if (stat & ATA_DSC) {
760                 if (stat & ATA_ERR) {
761                         /* Error detected */
762                         if (pc->c[0] != TEST_UNIT_READY)
763                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
764                                                 tape->name);
765                         /* Retry operation */
766                         ide_retry_pc(drive, tape->disk);
767                         return ide_stopped;
768                 }
769                 pc->error = 0;
770         } else {
771                 pc->error = IDETAPE_ERROR_GENERAL;
772                 tape->failed_pc = NULL;
773         }
774         drive->pc_callback(drive, 0);
775         return ide_stopped;
776 }
777
778 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
779                                    struct ide_atapi_pc *pc, struct request *rq,
780                                    u8 opcode)
781 {
782         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
783         unsigned int length = rq->current_nr_sectors;
784
785         ide_init_pc(pc);
786         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
787         pc->c[1] = 1;
788         pc->bh = bh;
789         pc->buf = NULL;
790         pc->buf_size = length * tape->blk_size;
791         pc->req_xfer = pc->buf_size;
792         if (pc->req_xfer == tape->buffer_size)
793                 pc->flags |= PC_FLAG_DMA_OK;
794
795         if (opcode == READ_6) {
796                 pc->c[0] = READ_6;
797                 atomic_set(&bh->b_count, 0);
798         } else if (opcode == WRITE_6) {
799                 pc->c[0] = WRITE_6;
800                 pc->flags |= PC_FLAG_WRITING;
801                 pc->b_data = bh->b_data;
802                 pc->b_count = atomic_read(&bh->b_count);
803         }
804
805         memcpy(rq->cmd, pc->c, 12);
806 }
807
808 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
809                                           struct request *rq, sector_t block)
810 {
811         ide_hwif_t *hwif = drive->hwif;
812         idetape_tape_t *tape = drive->driver_data;
813         struct ide_atapi_pc *pc = NULL;
814         struct request *postponed_rq = tape->postponed_rq;
815         u8 stat;
816
817         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
818                         " current_nr_sectors: %u\n",
819                         (unsigned long long)rq->sector, rq->nr_sectors,
820                         rq->current_nr_sectors);
821
822         if (!blk_special_request(rq)) {
823                 /* We do not support buffer cache originated requests. */
824                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
825                         "request queue (%d)\n", drive->name, rq->cmd_type);
826                 ide_end_request(drive, 0, 0);
827                 return ide_stopped;
828         }
829
830         /* Retry a failed packet command */
831         if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
832                 pc = tape->failed_pc;
833                 goto out;
834         }
835
836         if (postponed_rq != NULL)
837                 if (rq != postponed_rq) {
838                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
839                                         "Two DSC requests were queued\n");
840                         idetape_end_request(drive, 0, 0);
841                         return ide_stopped;
842                 }
843
844         tape->postponed_rq = NULL;
845
846         /*
847          * If the tape is still busy, postpone our request and service
848          * the other device meanwhile.
849          */
850         stat = hwif->tp_ops->read_status(hwif);
851
852         if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
853                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
854
855         if (drive->post_reset == 1) {
856                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
857                 drive->post_reset = 0;
858         }
859
860         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
861             (stat & ATA_DSC) == 0) {
862                 if (postponed_rq == NULL) {
863                         tape->dsc_polling_start = jiffies;
864                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
865                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
866                 } else if (time_after(jiffies, tape->dsc_timeout)) {
867                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
868                                 tape->name);
869                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
870                                 idetape_media_access_finished(drive);
871                                 return ide_stopped;
872                         } else {
873                                 return ide_do_reset(drive);
874                         }
875                 } else if (time_after(jiffies,
876                                         tape->dsc_polling_start +
877                                         IDETAPE_DSC_MA_THRESHOLD))
878                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
879                 idetape_postpone_request(drive);
880                 return ide_stopped;
881         }
882         if (rq->cmd[13] & REQ_IDETAPE_READ) {
883                 pc = &tape->queued_pc;
884                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
885                 goto out;
886         }
887         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
888                 pc = &tape->queued_pc;
889                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
890                 goto out;
891         }
892         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
893                 pc = (struct ide_atapi_pc *) rq->buffer;
894                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
895                 rq->cmd[13] |= REQ_IDETAPE_PC2;
896                 goto out;
897         }
898         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
899                 idetape_media_access_finished(drive);
900                 return ide_stopped;
901         }
902         BUG();
903
904 out:
905         return idetape_issue_pc(drive, pc);
906 }
907
908 /*
909  * The function below uses __get_free_pages to allocate a data buffer of size
910  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
911  * much as possible.
912  *
913  * It returns a pointer to the newly allocated buffer, or NULL in case of
914  * failure.
915  */
916 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
917                                                   int full, int clear)
918 {
919         struct idetape_bh *prev_bh, *bh, *merge_bh;
920         int pages = tape->pages_per_buffer;
921         unsigned int order, b_allocd;
922         char *b_data = NULL;
923
924         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
925         bh = merge_bh;
926         if (bh == NULL)
927                 goto abort;
928
929         order = fls(pages) - 1;
930         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
931         if (!bh->b_data)
932                 goto abort;
933         b_allocd = (1 << order) * PAGE_SIZE;
934         pages &= (order-1);
935
936         if (clear)
937                 memset(bh->b_data, 0, b_allocd);
938         bh->b_reqnext = NULL;
939         bh->b_size = b_allocd;
940         atomic_set(&bh->b_count, full ? bh->b_size : 0);
941
942         while (pages) {
943                 order = fls(pages) - 1;
944                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
945                 if (!b_data)
946                         goto abort;
947                 b_allocd = (1 << order) * PAGE_SIZE;
948
949                 if (clear)
950                         memset(b_data, 0, b_allocd);
951
952                 /* newly allocated page frames below buffer header or ...*/
953                 if (bh->b_data == b_data + b_allocd) {
954                         bh->b_size += b_allocd;
955                         bh->b_data -= b_allocd;
956                         if (full)
957                                 atomic_add(b_allocd, &bh->b_count);
958                         continue;
959                 }
960                 /* they are above the header */
961                 if (b_data == bh->b_data + bh->b_size) {
962                         bh->b_size += b_allocd;
963                         if (full)
964                                 atomic_add(b_allocd, &bh->b_count);
965                         continue;
966                 }
967                 prev_bh = bh;
968                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
969                 if (!bh) {
970                         free_pages((unsigned long) b_data, order);
971                         goto abort;
972                 }
973                 bh->b_reqnext = NULL;
974                 bh->b_data = b_data;
975                 bh->b_size = b_allocd;
976                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
977                 prev_bh->b_reqnext = bh;
978
979                 pages &= (order-1);
980         }
981
982         bh->b_size -= tape->excess_bh_size;
983         if (full)
984                 atomic_sub(tape->excess_bh_size, &bh->b_count);
985         return merge_bh;
986 abort:
987         ide_tape_kfree_buffer(tape);
988         return NULL;
989 }
990
991 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
992                                         const char __user *buf, int n)
993 {
994         struct idetape_bh *bh = tape->bh;
995         int count;
996         int ret = 0;
997
998         while (n) {
999                 if (bh == NULL) {
1000                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1001                                         __func__);
1002                         return 1;
1003                 }
1004                 count = min((unsigned int)
1005                                 (bh->b_size - atomic_read(&bh->b_count)),
1006                                 (unsigned int)n);
1007                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1008                                 count))
1009                         ret = 1;
1010                 n -= count;
1011                 atomic_add(count, &bh->b_count);
1012                 buf += count;
1013                 if (atomic_read(&bh->b_count) == bh->b_size) {
1014                         bh = bh->b_reqnext;
1015                         if (bh)
1016                                 atomic_set(&bh->b_count, 0);
1017                 }
1018         }
1019         tape->bh = bh;
1020         return ret;
1021 }
1022
1023 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1024                                       int n)
1025 {
1026         struct idetape_bh *bh = tape->bh;
1027         int count;
1028         int ret = 0;
1029
1030         while (n) {
1031                 if (bh == NULL) {
1032                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1033                                         __func__);
1034                         return 1;
1035                 }
1036                 count = min(tape->b_count, n);
1037                 if  (copy_to_user(buf, tape->b_data, count))
1038                         ret = 1;
1039                 n -= count;
1040                 tape->b_data += count;
1041                 tape->b_count -= count;
1042                 buf += count;
1043                 if (!tape->b_count) {
1044                         bh = bh->b_reqnext;
1045                         tape->bh = bh;
1046                         if (bh) {
1047                                 tape->b_data = bh->b_data;
1048                                 tape->b_count = atomic_read(&bh->b_count);
1049                         }
1050                 }
1051         }
1052         return ret;
1053 }
1054
1055 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1056 {
1057         struct idetape_bh *bh = tape->merge_bh;
1058         tape->bh = tape->merge_bh;
1059
1060         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1061                 atomic_set(&bh->b_count, 0);
1062         else {
1063                 tape->b_data = bh->b_data;
1064                 tape->b_count = atomic_read(&bh->b_count);
1065         }
1066 }
1067
1068 /*
1069  * Write a filemark if write_filemark=1. Flush the device buffers without
1070  * writing a filemark otherwise.
1071  */
1072 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1073                 struct ide_atapi_pc *pc, int write_filemark)
1074 {
1075         ide_init_pc(pc);
1076         pc->c[0] = WRITE_FILEMARKS;
1077         pc->c[4] = write_filemark;
1078         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1079 }
1080
1081 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1082 {
1083         idetape_tape_t *tape = drive->driver_data;
1084         struct gendisk *disk = tape->disk;
1085         int load_attempted = 0;
1086
1087         /* Wait for the tape to become ready */
1088         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1089         timeout += jiffies;
1090         while (time_before(jiffies, timeout)) {
1091                 if (ide_do_test_unit_ready(drive, disk) == 0)
1092                         return 0;
1093                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1094                     || (tape->asc == 0x3A)) {
1095                         /* no media */
1096                         if (load_attempted)
1097                                 return -ENOMEDIUM;
1098                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1099                         load_attempted = 1;
1100                 /* not about to be ready */
1101                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1102                              (tape->ascq == 1 || tape->ascq == 8)))
1103                         return -EIO;
1104                 msleep(100);
1105         }
1106         return -EIO;
1107 }
1108
1109 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1110 {
1111         struct ide_tape_obj *tape = drive->driver_data;
1112         struct ide_atapi_pc pc;
1113         int rc;
1114
1115         idetape_create_write_filemark_cmd(drive, &pc, 0);
1116         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1117         if (rc)
1118                 return rc;
1119         idetape_wait_ready(drive, 60 * 5 * HZ);
1120         return 0;
1121 }
1122
1123 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1124 {
1125         ide_init_pc(pc);
1126         pc->c[0] = READ_POSITION;
1127         pc->req_xfer = 20;
1128 }
1129
1130 static int idetape_read_position(ide_drive_t *drive)
1131 {
1132         idetape_tape_t *tape = drive->driver_data;
1133         struct ide_atapi_pc pc;
1134         int position;
1135
1136         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1137
1138         idetape_create_read_position_cmd(&pc);
1139         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1140                 return -1;
1141         position = tape->first_frame;
1142         return position;
1143 }
1144
1145 static void idetape_create_locate_cmd(ide_drive_t *drive,
1146                 struct ide_atapi_pc *pc,
1147                 unsigned int block, u8 partition, int skip)
1148 {
1149         ide_init_pc(pc);
1150         pc->c[0] = POSITION_TO_ELEMENT;
1151         pc->c[1] = 2;
1152         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1153         pc->c[8] = partition;
1154         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1155 }
1156
1157 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1158 {
1159         idetape_tape_t *tape = drive->driver_data;
1160
1161         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1162                 return;
1163
1164         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1165         tape->merge_bh_size = 0;
1166         if (tape->merge_bh != NULL) {
1167                 ide_tape_kfree_buffer(tape);
1168                 tape->merge_bh = NULL;
1169         }
1170
1171         tape->chrdev_dir = IDETAPE_DIR_NONE;
1172 }
1173
1174 /*
1175  * Position the tape to the requested block using the LOCATE packet command.
1176  * A READ POSITION command is then issued to check where we are positioned. Like
1177  * all higher level operations, we queue the commands at the tail of the request
1178  * queue and wait for their completion.
1179  */
1180 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1181                 u8 partition, int skip)
1182 {
1183         idetape_tape_t *tape = drive->driver_data;
1184         struct gendisk *disk = tape->disk;
1185         int retval;
1186         struct ide_atapi_pc pc;
1187
1188         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1189                 __ide_tape_discard_merge_buffer(drive);
1190         idetape_wait_ready(drive, 60 * 5 * HZ);
1191         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1192         retval = ide_queue_pc_tail(drive, disk, &pc);
1193         if (retval)
1194                 return (retval);
1195
1196         idetape_create_read_position_cmd(&pc);
1197         return ide_queue_pc_tail(drive, disk, &pc);
1198 }
1199
1200 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1201                                           int restore_position)
1202 {
1203         idetape_tape_t *tape = drive->driver_data;
1204         int seek, position;
1205
1206         __ide_tape_discard_merge_buffer(drive);
1207         if (restore_position) {
1208                 position = idetape_read_position(drive);
1209                 seek = position > 0 ? position : 0;
1210                 if (idetape_position_tape(drive, seek, 0, 0)) {
1211                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1212                                          " %s\n", tape->name, __func__);
1213                         return;
1214                 }
1215         }
1216 }
1217
1218 /*
1219  * Generate a read/write request for the block device interface and wait for it
1220  * to be serviced.
1221  */
1222 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1223                                  struct idetape_bh *bh)
1224 {
1225         idetape_tape_t *tape = drive->driver_data;
1226         struct request *rq;
1227         int ret, errors;
1228
1229         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1230
1231         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1232         rq->cmd_type = REQ_TYPE_SPECIAL;
1233         rq->cmd[13] = cmd;
1234         rq->rq_disk = tape->disk;
1235         rq->special = (void *)bh;
1236         rq->sector = tape->first_frame;
1237         rq->nr_sectors = blocks;
1238         rq->current_nr_sectors = blocks;
1239         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1240
1241         errors = rq->errors;
1242         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1243         blk_put_request(rq);
1244
1245         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1246                 return 0;
1247
1248         if (tape->merge_bh)
1249                 idetape_init_merge_buffer(tape);
1250         if (errors == IDETAPE_ERROR_GENERAL)
1251                 return -EIO;
1252         return ret;
1253 }
1254
1255 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1256 {
1257         ide_init_pc(pc);
1258         pc->c[0] = INQUIRY;
1259         pc->c[4] = 254;
1260         pc->req_xfer = 254;
1261 }
1262
1263 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1264                 struct ide_atapi_pc *pc)
1265 {
1266         ide_init_pc(pc);
1267         pc->c[0] = REZERO_UNIT;
1268         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1269 }
1270
1271 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1272 {
1273         ide_init_pc(pc);
1274         pc->c[0] = ERASE;
1275         pc->c[1] = 1;
1276         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1277 }
1278
1279 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1280 {
1281         ide_init_pc(pc);
1282         pc->c[0] = SPACE;
1283         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1284         pc->c[1] = cmd;
1285         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1286 }
1287
1288 /* Queue up a character device originated write request. */
1289 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1290 {
1291         idetape_tape_t *tape = drive->driver_data;
1292
1293         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1294
1295         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1296                                      blocks, tape->merge_bh);
1297 }
1298
1299 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1300 {
1301         idetape_tape_t *tape = drive->driver_data;
1302         int blocks, min;
1303         struct idetape_bh *bh;
1304
1305         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1306                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1307                                 " but we are not writing.\n");
1308                 return;
1309         }
1310         if (tape->merge_bh_size > tape->buffer_size) {
1311                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1312                 tape->merge_bh_size = tape->buffer_size;
1313         }
1314         if (tape->merge_bh_size) {
1315                 blocks = tape->merge_bh_size / tape->blk_size;
1316                 if (tape->merge_bh_size % tape->blk_size) {
1317                         unsigned int i;
1318
1319                         blocks++;
1320                         i = tape->blk_size - tape->merge_bh_size %
1321                                 tape->blk_size;
1322                         bh = tape->bh->b_reqnext;
1323                         while (bh) {
1324                                 atomic_set(&bh->b_count, 0);
1325                                 bh = bh->b_reqnext;
1326                         }
1327                         bh = tape->bh;
1328                         while (i) {
1329                                 if (bh == NULL) {
1330                                         printk(KERN_INFO "ide-tape: bug,"
1331                                                          " bh NULL\n");
1332                                         break;
1333                                 }
1334                                 min = min(i, (unsigned int)(bh->b_size -
1335                                                 atomic_read(&bh->b_count)));
1336                                 memset(bh->b_data + atomic_read(&bh->b_count),
1337                                                 0, min);
1338                                 atomic_add(min, &bh->b_count);
1339                                 i -= min;
1340                                 bh = bh->b_reqnext;
1341                         }
1342                 }
1343                 (void) idetape_add_chrdev_write_request(drive, blocks);
1344                 tape->merge_bh_size = 0;
1345         }
1346         if (tape->merge_bh != NULL) {
1347                 ide_tape_kfree_buffer(tape);
1348                 tape->merge_bh = NULL;
1349         }
1350         tape->chrdev_dir = IDETAPE_DIR_NONE;
1351 }
1352
1353 static int idetape_init_read(ide_drive_t *drive)
1354 {
1355         idetape_tape_t *tape = drive->driver_data;
1356         int bytes_read;
1357
1358         /* Initialize read operation */
1359         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1360                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1361                         ide_tape_flush_merge_buffer(drive);
1362                         idetape_flush_tape_buffers(drive);
1363                 }
1364                 if (tape->merge_bh || tape->merge_bh_size) {
1365                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1366                                          " 0 now\n");
1367                         tape->merge_bh_size = 0;
1368                 }
1369                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1370                 if (!tape->merge_bh)
1371                         return -ENOMEM;
1372                 tape->chrdev_dir = IDETAPE_DIR_READ;
1373
1374                 /*
1375                  * Issue a read 0 command to ensure that DSC handshake is
1376                  * switched from completion mode to buffer available mode.
1377                  * No point in issuing this if DSC overlap isn't supported, some
1378                  * drives (Seagate STT3401A) will return an error.
1379                  */
1380                 if (drive->dsc_overlap) {
1381                         bytes_read = idetape_queue_rw_tail(drive,
1382                                                         REQ_IDETAPE_READ, 0,
1383                                                         tape->merge_bh);
1384                         if (bytes_read < 0) {
1385                                 ide_tape_kfree_buffer(tape);
1386                                 tape->merge_bh = NULL;
1387                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1388                                 return bytes_read;
1389                         }
1390                 }
1391         }
1392
1393         return 0;
1394 }
1395
1396 /* called from idetape_chrdev_read() to service a chrdev read request. */
1397 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1398 {
1399         idetape_tape_t *tape = drive->driver_data;
1400
1401         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1402
1403         /* If we are at a filemark, return a read length of 0 */
1404         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1405                 return 0;
1406
1407         idetape_init_read(drive);
1408
1409         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1410                                      tape->merge_bh);
1411 }
1412
1413 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1414 {
1415         idetape_tape_t *tape = drive->driver_data;
1416         struct idetape_bh *bh;
1417         int blocks;
1418
1419         while (bcount) {
1420                 unsigned int count;
1421
1422                 bh = tape->merge_bh;
1423                 count = min(tape->buffer_size, bcount);
1424                 bcount -= count;
1425                 blocks = count / tape->blk_size;
1426                 while (count) {
1427                         atomic_set(&bh->b_count,
1428                                    min(count, (unsigned int)bh->b_size));
1429                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1430                         count -= atomic_read(&bh->b_count);
1431                         bh = bh->b_reqnext;
1432                 }
1433                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1434                                       tape->merge_bh);
1435         }
1436 }
1437
1438 /*
1439  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1440  * currently support only one partition.
1441  */
1442 static int idetape_rewind_tape(ide_drive_t *drive)
1443 {
1444         struct ide_tape_obj *tape = drive->driver_data;
1445         struct gendisk *disk = tape->disk;
1446         int retval;
1447         struct ide_atapi_pc pc;
1448
1449         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1450
1451         idetape_create_rewind_cmd(drive, &pc);
1452         retval = ide_queue_pc_tail(drive, disk, &pc);
1453         if (retval)
1454                 return retval;
1455
1456         idetape_create_read_position_cmd(&pc);
1457         retval = ide_queue_pc_tail(drive, disk, &pc);
1458         if (retval)
1459                 return retval;
1460         return 0;
1461 }
1462
1463 /* mtio.h compatible commands should be issued to the chrdev interface. */
1464 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1465                                 unsigned long arg)
1466 {
1467         idetape_tape_t *tape = drive->driver_data;
1468         void __user *argp = (void __user *)arg;
1469
1470         struct idetape_config {
1471                 int dsc_rw_frequency;
1472                 int dsc_media_access_frequency;
1473                 int nr_stages;
1474         } config;
1475
1476         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1477
1478         switch (cmd) {
1479         case 0x0340:
1480                 if (copy_from_user(&config, argp, sizeof(config)))
1481                         return -EFAULT;
1482                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1483                 break;
1484         case 0x0350:
1485                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1486                 config.nr_stages = 1;
1487                 if (copy_to_user(argp, &config, sizeof(config)))
1488                         return -EFAULT;
1489                 break;
1490         default:
1491                 return -EIO;
1492         }
1493         return 0;
1494 }
1495
1496 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1497                                         int mt_count)
1498 {
1499         idetape_tape_t *tape = drive->driver_data;
1500         struct gendisk *disk = tape->disk;
1501         struct ide_atapi_pc pc;
1502         int retval, count = 0;
1503         int sprev = !!(tape->caps[4] & 0x20);
1504
1505         if (mt_count == 0)
1506                 return 0;
1507         if (MTBSF == mt_op || MTBSFM == mt_op) {
1508                 if (!sprev)
1509                         return -EIO;
1510                 mt_count = -mt_count;
1511         }
1512
1513         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1514                 tape->merge_bh_size = 0;
1515                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1516                         ++count;
1517                 ide_tape_discard_merge_buffer(drive, 0);
1518         }
1519
1520         switch (mt_op) {
1521         case MTFSF:
1522         case MTBSF:
1523                 idetape_create_space_cmd(&pc, mt_count - count,
1524                                          IDETAPE_SPACE_OVER_FILEMARK);
1525                 return ide_queue_pc_tail(drive, disk, &pc);
1526         case MTFSFM:
1527         case MTBSFM:
1528                 if (!sprev)
1529                         return -EIO;
1530                 retval = idetape_space_over_filemarks(drive, MTFSF,
1531                                                       mt_count - count);
1532                 if (retval)
1533                         return retval;
1534                 count = (MTBSFM == mt_op ? 1 : -1);
1535                 return idetape_space_over_filemarks(drive, MTFSF, count);
1536         default:
1537                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1538                                 mt_op);
1539                 return -EIO;
1540         }
1541 }
1542
1543 /*
1544  * Our character device read / write functions.
1545  *
1546  * The tape is optimized to maximize throughput when it is transferring an
1547  * integral number of the "continuous transfer limit", which is a parameter of
1548  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1549  *
1550  * As of version 1.3 of the driver, the character device provides an abstract
1551  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1552  * same backup/restore procedure is supported. The driver will internally
1553  * convert the requests to the recommended transfer unit, so that an unmatch
1554  * between the user's block size to the recommended size will only result in a
1555  * (slightly) increased driver overhead, but will no longer hit performance.
1556  * This is not applicable to Onstream.
1557  */
1558 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1559                                    size_t count, loff_t *ppos)
1560 {
1561         struct ide_tape_obj *tape = ide_tape_f(file);
1562         ide_drive_t *drive = tape->drive;
1563         ssize_t bytes_read, temp, actually_read = 0, rc;
1564         ssize_t ret = 0;
1565         u16 ctl = *(u16 *)&tape->caps[12];
1566
1567         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1568
1569         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1570                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1571                         if (count > tape->blk_size &&
1572                             (count % tape->blk_size) == 0)
1573                                 tape->user_bs_factor = count / tape->blk_size;
1574         }
1575         rc = idetape_init_read(drive);
1576         if (rc < 0)
1577                 return rc;
1578         if (count == 0)
1579                 return (0);
1580         if (tape->merge_bh_size) {
1581                 actually_read = min((unsigned int)(tape->merge_bh_size),
1582                                     (unsigned int)count);
1583                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1584                         ret = -EFAULT;
1585                 buf += actually_read;
1586                 tape->merge_bh_size -= actually_read;
1587                 count -= actually_read;
1588         }
1589         while (count >= tape->buffer_size) {
1590                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1591                 if (bytes_read <= 0)
1592                         goto finish;
1593                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1594                         ret = -EFAULT;
1595                 buf += bytes_read;
1596                 count -= bytes_read;
1597                 actually_read += bytes_read;
1598         }
1599         if (count) {
1600                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1601                 if (bytes_read <= 0)
1602                         goto finish;
1603                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1604                 if (idetape_copy_stage_to_user(tape, buf, temp))
1605                         ret = -EFAULT;
1606                 actually_read += temp;
1607                 tape->merge_bh_size = bytes_read-temp;
1608         }
1609 finish:
1610         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1611                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1612
1613                 idetape_space_over_filemarks(drive, MTFSF, 1);
1614                 return 0;
1615         }
1616
1617         return ret ? ret : actually_read;
1618 }
1619
1620 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1621                                      size_t count, loff_t *ppos)
1622 {
1623         struct ide_tape_obj *tape = ide_tape_f(file);
1624         ide_drive_t *drive = tape->drive;
1625         ssize_t actually_written = 0;
1626         ssize_t ret = 0;
1627         u16 ctl = *(u16 *)&tape->caps[12];
1628
1629         /* The drive is write protected. */
1630         if (tape->write_prot)
1631                 return -EACCES;
1632
1633         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1634
1635         /* Initialize write operation */
1636         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1637                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1638                         ide_tape_discard_merge_buffer(drive, 1);
1639                 if (tape->merge_bh || tape->merge_bh_size) {
1640                         printk(KERN_ERR "ide-tape: merge_bh_size "
1641                                 "should be 0 now\n");
1642                         tape->merge_bh_size = 0;
1643                 }
1644                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1645                 if (!tape->merge_bh)
1646                         return -ENOMEM;
1647                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1648                 idetape_init_merge_buffer(tape);
1649
1650                 /*
1651                  * Issue a write 0 command to ensure that DSC handshake is
1652                  * switched from completion mode to buffer available mode. No
1653                  * point in issuing this if DSC overlap isn't supported, some
1654                  * drives (Seagate STT3401A) will return an error.
1655                  */
1656                 if (drive->dsc_overlap) {
1657                         ssize_t retval = idetape_queue_rw_tail(drive,
1658                                                         REQ_IDETAPE_WRITE, 0,
1659                                                         tape->merge_bh);
1660                         if (retval < 0) {
1661                                 ide_tape_kfree_buffer(tape);
1662                                 tape->merge_bh = NULL;
1663                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1664                                 return retval;
1665                         }
1666                 }
1667         }
1668         if (count == 0)
1669                 return (0);
1670         if (tape->merge_bh_size) {
1671                 if (tape->merge_bh_size >= tape->buffer_size) {
1672                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1673                         tape->merge_bh_size = 0;
1674                 }
1675                 actually_written = min((unsigned int)
1676                                 (tape->buffer_size - tape->merge_bh_size),
1677                                 (unsigned int)count);
1678                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1679                                 ret = -EFAULT;
1680                 buf += actually_written;
1681                 tape->merge_bh_size += actually_written;
1682                 count -= actually_written;
1683
1684                 if (tape->merge_bh_size == tape->buffer_size) {
1685                         ssize_t retval;
1686                         tape->merge_bh_size = 0;
1687                         retval = idetape_add_chrdev_write_request(drive, ctl);
1688                         if (retval <= 0)
1689                                 return (retval);
1690                 }
1691         }
1692         while (count >= tape->buffer_size) {
1693                 ssize_t retval;
1694                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1695                         ret = -EFAULT;
1696                 buf += tape->buffer_size;
1697                 count -= tape->buffer_size;
1698                 retval = idetape_add_chrdev_write_request(drive, ctl);
1699                 actually_written += tape->buffer_size;
1700                 if (retval <= 0)
1701                         return (retval);
1702         }
1703         if (count) {
1704                 actually_written += count;
1705                 if (idetape_copy_stage_from_user(tape, buf, count))
1706                         ret = -EFAULT;
1707                 tape->merge_bh_size += count;
1708         }
1709         return ret ? ret : actually_written;
1710 }
1711
1712 static int idetape_write_filemark(ide_drive_t *drive)
1713 {
1714         struct ide_tape_obj *tape = drive->driver_data;
1715         struct ide_atapi_pc pc;
1716
1717         /* Write a filemark */
1718         idetape_create_write_filemark_cmd(drive, &pc, 1);
1719         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1720                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1721                 return -EIO;
1722         }
1723         return 0;
1724 }
1725
1726 /*
1727  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1728  * requested.
1729  *
1730  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1731  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1732  * usually not supported.
1733  *
1734  * The following commands are currently not supported:
1735  *
1736  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1737  * MT_ST_WRITE_THRESHOLD.
1738  */
1739 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1740 {
1741         idetape_tape_t *tape = drive->driver_data;
1742         struct gendisk *disk = tape->disk;
1743         struct ide_atapi_pc pc;
1744         int i, retval;
1745
1746         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1747                         mt_op, mt_count);
1748
1749         switch (mt_op) {
1750         case MTFSF:
1751         case MTFSFM:
1752         case MTBSF:
1753         case MTBSFM:
1754                 if (!mt_count)
1755                         return 0;
1756                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1757         default:
1758                 break;
1759         }
1760
1761         switch (mt_op) {
1762         case MTWEOF:
1763                 if (tape->write_prot)
1764                         return -EACCES;
1765                 ide_tape_discard_merge_buffer(drive, 1);
1766                 for (i = 0; i < mt_count; i++) {
1767                         retval = idetape_write_filemark(drive);
1768                         if (retval)
1769                                 return retval;
1770                 }
1771                 return 0;
1772         case MTREW:
1773                 ide_tape_discard_merge_buffer(drive, 0);
1774                 if (idetape_rewind_tape(drive))
1775                         return -EIO;
1776                 return 0;
1777         case MTLOAD:
1778                 ide_tape_discard_merge_buffer(drive, 0);
1779                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1780         case MTUNLOAD:
1781         case MTOFFL:
1782                 /*
1783                  * If door is locked, attempt to unlock before
1784                  * attempting to eject.
1785                  */
1786                 if (tape->door_locked) {
1787                         if (!ide_set_media_lock(drive, disk, 0))
1788                                 tape->door_locked = DOOR_UNLOCKED;
1789                 }
1790                 ide_tape_discard_merge_buffer(drive, 0);
1791                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1792                 if (!retval)
1793                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1794                 return retval;
1795         case MTNOP:
1796                 ide_tape_discard_merge_buffer(drive, 0);
1797                 return idetape_flush_tape_buffers(drive);
1798         case MTRETEN:
1799                 ide_tape_discard_merge_buffer(drive, 0);
1800                 return ide_do_start_stop(drive, disk,
1801                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1802         case MTEOM:
1803                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1804                 return ide_queue_pc_tail(drive, disk, &pc);
1805         case MTERASE:
1806                 (void)idetape_rewind_tape(drive);
1807                 idetape_create_erase_cmd(&pc);
1808                 return ide_queue_pc_tail(drive, disk, &pc);
1809         case MTSETBLK:
1810                 if (mt_count) {
1811                         if (mt_count < tape->blk_size ||
1812                             mt_count % tape->blk_size)
1813                                 return -EIO;
1814                         tape->user_bs_factor = mt_count / tape->blk_size;
1815                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1816                 } else
1817                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1818                 return 0;
1819         case MTSEEK:
1820                 ide_tape_discard_merge_buffer(drive, 0);
1821                 return idetape_position_tape(drive,
1822                         mt_count * tape->user_bs_factor, tape->partition, 0);
1823         case MTSETPART:
1824                 ide_tape_discard_merge_buffer(drive, 0);
1825                 return idetape_position_tape(drive, 0, mt_count, 0);
1826         case MTFSR:
1827         case MTBSR:
1828         case MTLOCK:
1829                 retval = ide_set_media_lock(drive, disk, 1);
1830                 if (retval)
1831                         return retval;
1832                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1833                 return 0;
1834         case MTUNLOCK:
1835                 retval = ide_set_media_lock(drive, disk, 0);
1836                 if (retval)
1837                         return retval;
1838                 tape->door_locked = DOOR_UNLOCKED;
1839                 return 0;
1840         default:
1841                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1842                                 mt_op);
1843                 return -EIO;
1844         }
1845 }
1846
1847 /*
1848  * Our character device ioctls. General mtio.h magnetic io commands are
1849  * supported here, and not in the corresponding block interface. Our own
1850  * ide-tape ioctls are supported on both interfaces.
1851  */
1852 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1853                                 unsigned int cmd, unsigned long arg)
1854 {
1855         struct ide_tape_obj *tape = ide_tape_f(file);
1856         ide_drive_t *drive = tape->drive;
1857         struct mtop mtop;
1858         struct mtget mtget;
1859         struct mtpos mtpos;
1860         int block_offset = 0, position = tape->first_frame;
1861         void __user *argp = (void __user *)arg;
1862
1863         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1864
1865         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1866                 ide_tape_flush_merge_buffer(drive);
1867                 idetape_flush_tape_buffers(drive);
1868         }
1869         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1870                 block_offset = tape->merge_bh_size /
1871                         (tape->blk_size * tape->user_bs_factor);
1872                 position = idetape_read_position(drive);
1873                 if (position < 0)
1874                         return -EIO;
1875         }
1876         switch (cmd) {
1877         case MTIOCTOP:
1878                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1879                         return -EFAULT;
1880                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1881         case MTIOCGET:
1882                 memset(&mtget, 0, sizeof(struct mtget));
1883                 mtget.mt_type = MT_ISSCSI2;
1884                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1885                 mtget.mt_dsreg =
1886                         ((tape->blk_size * tape->user_bs_factor)
1887                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1888
1889                 if (tape->drv_write_prot)
1890                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1891
1892                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1893                         return -EFAULT;
1894                 return 0;
1895         case MTIOCPOS:
1896                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1897                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1898                         return -EFAULT;
1899                 return 0;
1900         default:
1901                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1902                         ide_tape_discard_merge_buffer(drive, 1);
1903                 return idetape_blkdev_ioctl(drive, cmd, arg);
1904         }
1905 }
1906
1907 /*
1908  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1909  * block size with the reported value.
1910  */
1911 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1912 {
1913         idetape_tape_t *tape = drive->driver_data;
1914         struct ide_atapi_pc pc;
1915
1916         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1917         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1918                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1919                 if (tape->blk_size == 0) {
1920                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1921                                             "block size, assuming 32k\n");
1922                         tape->blk_size = 32768;
1923                 }
1924                 return;
1925         }
1926         tape->blk_size = (pc.buf[4 + 5] << 16) +
1927                                 (pc.buf[4 + 6] << 8)  +
1928                                  pc.buf[4 + 7];
1929         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
1930 }
1931
1932 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1933 {
1934         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1935         ide_drive_t *drive;
1936         idetape_tape_t *tape;
1937         int retval;
1938
1939         if (i >= MAX_HWIFS * MAX_DRIVES)
1940                 return -ENXIO;
1941
1942         lock_kernel();
1943         tape = ide_tape_chrdev_get(i);
1944         if (!tape) {
1945                 unlock_kernel();
1946                 return -ENXIO;
1947         }
1948
1949         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1950
1951         /*
1952          * We really want to do nonseekable_open(inode, filp); here, but some
1953          * versions of tar incorrectly call lseek on tapes and bail out if that
1954          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1955          */
1956         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1957
1958         drive = tape->drive;
1959
1960         filp->private_data = tape;
1961
1962         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
1963                 retval = -EBUSY;
1964                 goto out_put_tape;
1965         }
1966
1967         retval = idetape_wait_ready(drive, 60 * HZ);
1968         if (retval) {
1969                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1970                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1971                 goto out_put_tape;
1972         }
1973
1974         idetape_read_position(drive);
1975         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
1976                 (void)idetape_rewind_tape(drive);
1977
1978         /* Read block size and write protect status from drive. */
1979         ide_tape_get_bsize_from_bdesc(drive);
1980
1981         /* Set write protect flag if device is opened as read-only. */
1982         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1983                 tape->write_prot = 1;
1984         else
1985                 tape->write_prot = tape->drv_write_prot;
1986
1987         /* Make sure drive isn't write protected if user wants to write. */
1988         if (tape->write_prot) {
1989                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1990                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1991                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
1992                         retval = -EROFS;
1993                         goto out_put_tape;
1994                 }
1995         }
1996
1997         /* Lock the tape drive door so user can't eject. */
1998         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1999                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
2000                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2001                                 tape->door_locked = DOOR_LOCKED;
2002                 }
2003         }
2004         unlock_kernel();
2005         return 0;
2006
2007 out_put_tape:
2008         ide_tape_put(tape);
2009         unlock_kernel();
2010         return retval;
2011 }
2012
2013 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2014 {
2015         idetape_tape_t *tape = drive->driver_data;
2016
2017         ide_tape_flush_merge_buffer(drive);
2018         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2019         if (tape->merge_bh != NULL) {
2020                 idetape_pad_zeros(drive, tape->blk_size *
2021                                 (tape->user_bs_factor - 1));
2022                 ide_tape_kfree_buffer(tape);
2023                 tape->merge_bh = NULL;
2024         }
2025         idetape_write_filemark(drive);
2026         idetape_flush_tape_buffers(drive);
2027         idetape_flush_tape_buffers(drive);
2028 }
2029
2030 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2031 {
2032         struct ide_tape_obj *tape = ide_tape_f(filp);
2033         ide_drive_t *drive = tape->drive;
2034         unsigned int minor = iminor(inode);
2035
2036         lock_kernel();
2037         tape = drive->driver_data;
2038
2039         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2040
2041         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2042                 idetape_write_release(drive, minor);
2043         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2044                 if (minor < 128)
2045                         ide_tape_discard_merge_buffer(drive, 1);
2046         }
2047
2048         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2049                 (void) idetape_rewind_tape(drive);
2050         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2051                 if (tape->door_locked == DOOR_LOCKED) {
2052                         if (!ide_set_media_lock(drive, tape->disk, 0))
2053                                 tape->door_locked = DOOR_UNLOCKED;
2054                 }
2055         }
2056         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2057         ide_tape_put(tape);
2058         unlock_kernel();
2059         return 0;
2060 }
2061
2062 static void idetape_get_inquiry_results(ide_drive_t *drive)
2063 {
2064         idetape_tape_t *tape = drive->driver_data;
2065         struct ide_atapi_pc pc;
2066         char fw_rev[4], vendor_id[8], product_id[16];
2067
2068         idetape_create_inquiry_cmd(&pc);
2069         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2070                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2071                                 tape->name);
2072                 return;
2073         }
2074         memcpy(vendor_id, &pc.buf[8], 8);
2075         memcpy(product_id, &pc.buf[16], 16);
2076         memcpy(fw_rev, &pc.buf[32], 4);
2077
2078         ide_fixstring(vendor_id, 8, 0);
2079         ide_fixstring(product_id, 16, 0);
2080         ide_fixstring(fw_rev, 4, 0);
2081
2082         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2083                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2084 }
2085
2086 /*
2087  * Ask the tape about its various parameters. In particular, we will adjust our
2088  * data transfer buffer size to the recommended value as returned by the tape.
2089  */
2090 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2091 {
2092         idetape_tape_t *tape = drive->driver_data;
2093         struct ide_atapi_pc pc;
2094         u8 *caps;
2095         u8 speed, max_speed;
2096
2097         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2098         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2099                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2100                                 " some default values\n");
2101                 tape->blk_size = 512;
2102                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2103                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2104                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2105                 return;
2106         }
2107         caps = pc.buf + 4 + pc.buf[3];
2108
2109         /* convert to host order and save for later use */
2110         speed = be16_to_cpup((__be16 *)&caps[14]);
2111         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2112
2113         *(u16 *)&caps[8] = max_speed;
2114         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2115         *(u16 *)&caps[14] = speed;
2116         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2117
2118         if (!speed) {
2119                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2120                                 "(assuming 650KB/sec)\n", drive->name);
2121                 *(u16 *)&caps[14] = 650;
2122         }
2123         if (!max_speed) {
2124                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2125                                 "(assuming 650KB/sec)\n", drive->name);
2126                 *(u16 *)&caps[8] = 650;
2127         }
2128
2129         memcpy(&tape->caps, caps, 20);
2130
2131         /* device lacks locking support according to capabilities page */
2132         if ((caps[6] & 1) == 0)
2133                 drive->atapi_flags |= IDE_AFLAG_NO_DOORLOCK;
2134
2135         if (caps[7] & 0x02)
2136                 tape->blk_size = 512;
2137         else if (caps[7] & 0x04)
2138                 tape->blk_size = 1024;
2139 }
2140
2141 #ifdef CONFIG_IDE_PROC_FS
2142 #define ide_tape_devset_get(name, field) \
2143 static int get_##name(ide_drive_t *drive) \
2144 { \
2145         idetape_tape_t *tape = drive->driver_data; \
2146         return tape->field; \
2147 }
2148
2149 #define ide_tape_devset_set(name, field) \
2150 static int set_##name(ide_drive_t *drive, int arg) \
2151 { \
2152         idetape_tape_t *tape = drive->driver_data; \
2153         tape->field = arg; \
2154         return 0; \
2155 }
2156
2157 #define ide_tape_devset_rw_field(_name, _field) \
2158 ide_tape_devset_get(_name, _field) \
2159 ide_tape_devset_set(_name, _field) \
2160 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
2161
2162 #define ide_tape_devset_r_field(_name, _field) \
2163 ide_tape_devset_get(_name, _field) \
2164 IDE_DEVSET(_name, 0, get_##_name, NULL)
2165
2166 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2167 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2168 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2169 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2170
2171 ide_devset_rw_field(dsc_overlap, dsc_overlap);
2172
2173 ide_tape_devset_rw_field(debug_mask, debug_mask);
2174 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
2175
2176 ide_tape_devset_r_field(avg_speed, avg_speed);
2177 ide_tape_devset_r_field(speed, caps[14]);
2178 ide_tape_devset_r_field(buffer, caps[16]);
2179 ide_tape_devset_r_field(buffer_size, buffer_size);
2180
2181 static const struct ide_proc_devset idetape_settings[] = {
2182         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
2183         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
2184         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
2185         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
2186         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
2187         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
2188         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2189                                         mulf_tdsc, divf_tdsc),
2190         { 0 },
2191 };
2192 #endif
2193
2194 /*
2195  * The function below is called to:
2196  *
2197  * 1. Initialize our various state variables.
2198  * 2. Ask the tape for its capabilities.
2199  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2200  * is chosen based on the recommendation which we received in step 2.
2201  *
2202  * Note that at this point ide.c already assigned us an irq, so that we can
2203  * queue requests here and wait for their completion.
2204  */
2205 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2206 {
2207         unsigned long t;
2208         int speed;
2209         int buffer_size;
2210         u8 gcw[2];
2211         u16 *ctl = (u16 *)&tape->caps[12];
2212
2213         drive->pc_callback       = ide_tape_callback;
2214         drive->pc_update_buffers = idetape_update_buffers;
2215         drive->pc_io_buffers     = ide_tape_io_buffers;
2216
2217         spin_lock_init(&tape->lock);
2218         drive->dsc_overlap = 1;
2219         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2220                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2221                                  tape->name);
2222                 drive->dsc_overlap = 0;
2223         }
2224         /* Seagate Travan drives do not support DSC overlap. */
2225         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2226                 drive->dsc_overlap = 0;
2227         tape->minor = minor;
2228         tape->name[0] = 'h';
2229         tape->name[1] = 't';
2230         tape->name[2] = '0' + minor;
2231         tape->chrdev_dir = IDETAPE_DIR_NONE;
2232
2233         *((u16 *)&gcw) = drive->id[ATA_ID_CONFIG];
2234
2235         /* Command packet DRQ type */
2236         if (((gcw[0] & 0x60) >> 5) == 1)
2237                 set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
2238
2239         idetape_get_inquiry_results(drive);
2240         idetape_get_mode_sense_results(drive);
2241         ide_tape_get_bsize_from_bdesc(drive);
2242         tape->user_bs_factor = 1;
2243         tape->buffer_size = *ctl * tape->blk_size;
2244         while (tape->buffer_size > 0xffff) {
2245                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2246                 *ctl /= 2;
2247                 tape->buffer_size = *ctl * tape->blk_size;
2248         }
2249         buffer_size = tape->buffer_size;
2250         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2251         if (buffer_size % PAGE_SIZE) {
2252                 tape->pages_per_buffer++;
2253                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2254         }
2255
2256         /* select the "best" DSC read/write polling freq */
2257         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2258
2259         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2260
2261         /*
2262          * Ensure that the number we got makes sense; limit it within
2263          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2264          */
2265         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2266                                          IDETAPE_DSC_RW_MAX);
2267         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2268                 "%lums tDSC%s\n",
2269                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2270                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2271                 tape->buffer_size / 1024,
2272                 tape->best_dsc_rw_freq * 1000 / HZ,
2273                 drive->using_dma ? ", DMA":"");
2274
2275         ide_proc_register_driver(drive, tape->driver);
2276 }
2277
2278 static void ide_tape_remove(ide_drive_t *drive)
2279 {
2280         idetape_tape_t *tape = drive->driver_data;
2281
2282         ide_proc_unregister_driver(drive, tape->driver);
2283
2284         ide_unregister_region(tape->disk);
2285
2286         ide_tape_put(tape);
2287 }
2288
2289 static void ide_tape_release(struct kref *kref)
2290 {
2291         struct ide_tape_obj *tape = to_ide_tape(kref);
2292         ide_drive_t *drive = tape->drive;
2293         struct gendisk *g = tape->disk;
2294
2295         BUG_ON(tape->merge_bh_size);
2296
2297         drive->dsc_overlap = 0;
2298         drive->driver_data = NULL;
2299         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2300         device_destroy(idetape_sysfs_class,
2301                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2302         idetape_devs[tape->minor] = NULL;
2303         g->private_data = NULL;
2304         put_disk(g);
2305         kfree(tape);
2306 }
2307
2308 #ifdef CONFIG_IDE_PROC_FS
2309 static int proc_idetape_read_name
2310         (char *page, char **start, off_t off, int count, int *eof, void *data)
2311 {
2312         ide_drive_t     *drive = (ide_drive_t *) data;
2313         idetape_tape_t  *tape = drive->driver_data;
2314         char            *out = page;
2315         int             len;
2316
2317         len = sprintf(out, "%s\n", tape->name);
2318         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2319 }
2320
2321 static ide_proc_entry_t idetape_proc[] = {
2322         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2323         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2324         { NULL, 0, NULL, NULL }
2325 };
2326 #endif
2327
2328 static int ide_tape_probe(ide_drive_t *);
2329
2330 static ide_driver_t idetape_driver = {
2331         .gen_driver = {
2332                 .owner          = THIS_MODULE,
2333                 .name           = "ide-tape",
2334                 .bus            = &ide_bus_type,
2335         },
2336         .probe                  = ide_tape_probe,
2337         .remove                 = ide_tape_remove,
2338         .version                = IDETAPE_VERSION,
2339         .media                  = ide_tape,
2340         .do_request             = idetape_do_request,
2341         .end_request            = idetape_end_request,
2342         .error                  = __ide_error,
2343 #ifdef CONFIG_IDE_PROC_FS
2344         .proc                   = idetape_proc,
2345         .settings               = idetape_settings,
2346 #endif
2347 };
2348
2349 /* Our character device supporting functions, passed to register_chrdev. */
2350 static const struct file_operations idetape_fops = {
2351         .owner          = THIS_MODULE,
2352         .read           = idetape_chrdev_read,
2353         .write          = idetape_chrdev_write,
2354         .ioctl          = idetape_chrdev_ioctl,
2355         .open           = idetape_chrdev_open,
2356         .release        = idetape_chrdev_release,
2357 };
2358
2359 static int idetape_open(struct inode *inode, struct file *filp)
2360 {
2361         struct gendisk *disk = inode->i_bdev->bd_disk;
2362         struct ide_tape_obj *tape;
2363
2364         tape = ide_tape_get(disk);
2365         if (!tape)
2366                 return -ENXIO;
2367
2368         return 0;
2369 }
2370
2371 static int idetape_release(struct inode *inode, struct file *filp)
2372 {
2373         struct gendisk *disk = inode->i_bdev->bd_disk;
2374         struct ide_tape_obj *tape = ide_tape_g(disk);
2375
2376         ide_tape_put(tape);
2377
2378         return 0;
2379 }
2380
2381 static int idetape_ioctl(struct inode *inode, struct file *file,
2382                         unsigned int cmd, unsigned long arg)
2383 {
2384         struct block_device *bdev = inode->i_bdev;
2385         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2386         ide_drive_t *drive = tape->drive;
2387         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2388         if (err == -EINVAL)
2389                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2390         return err;
2391 }
2392
2393 static struct block_device_operations idetape_block_ops = {
2394         .owner          = THIS_MODULE,
2395         .open           = idetape_open,
2396         .release        = idetape_release,
2397         .ioctl          = idetape_ioctl,
2398 };
2399
2400 static int ide_tape_probe(ide_drive_t *drive)
2401 {
2402         idetape_tape_t *tape;
2403         struct gendisk *g;
2404         int minor;
2405
2406         if (!strstr("ide-tape", drive->driver_req))
2407                 goto failed;
2408
2409         if (drive->media != ide_tape)
2410                 goto failed;
2411
2412         if (drive->id_read == 1 && !ide_check_atapi_device(drive, DRV_NAME)) {
2413                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2414                                 " the driver\n", drive->name);
2415                 goto failed;
2416         }
2417         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2418         if (tape == NULL) {
2419                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2420                                 drive->name);
2421                 goto failed;
2422         }
2423
2424         g = alloc_disk(1 << PARTN_BITS);
2425         if (!g)
2426                 goto out_free_tape;
2427
2428         ide_init_disk(g, drive);
2429
2430         kref_init(&tape->kref);
2431
2432         tape->drive = drive;
2433         tape->driver = &idetape_driver;
2434         tape->disk = g;
2435
2436         g->private_data = &tape->driver;
2437
2438         drive->driver_data = tape;
2439
2440         mutex_lock(&idetape_ref_mutex);
2441         for (minor = 0; idetape_devs[minor]; minor++)
2442                 ;
2443         idetape_devs[minor] = tape;
2444         mutex_unlock(&idetape_ref_mutex);
2445
2446         idetape_setup(drive, tape, minor);
2447
2448         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2449                               MKDEV(IDETAPE_MAJOR, minor), NULL,
2450                               "%s", tape->name);
2451         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2452                               MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2453                               "n%s", tape->name);
2454
2455         g->fops = &idetape_block_ops;
2456         ide_register_region(g);
2457
2458         return 0;
2459
2460 out_free_tape:
2461         kfree(tape);
2462 failed:
2463         return -ENODEV;
2464 }
2465
2466 static void __exit idetape_exit(void)
2467 {
2468         driver_unregister(&idetape_driver.gen_driver);
2469         class_destroy(idetape_sysfs_class);
2470         unregister_chrdev(IDETAPE_MAJOR, "ht");
2471 }
2472
2473 static int __init idetape_init(void)
2474 {
2475         int error = 1;
2476         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2477         if (IS_ERR(idetape_sysfs_class)) {
2478                 idetape_sysfs_class = NULL;
2479                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2480                 error = -EBUSY;
2481                 goto out;
2482         }
2483
2484         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2485                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2486                                 " interface\n");
2487                 error = -EBUSY;
2488                 goto out_free_class;
2489         }
2490
2491         error = driver_register(&idetape_driver.gen_driver);
2492         if (error)
2493                 goto out_free_driver;
2494
2495         return 0;
2496
2497 out_free_driver:
2498         driver_unregister(&idetape_driver.gen_driver);
2499 out_free_class:
2500         class_destroy(idetape_sysfs_class);
2501 out:
2502         return error;
2503 }
2504
2505 MODULE_ALIAS("ide:*m-tape*");
2506 module_init(idetape_init);
2507 module_exit(idetape_exit);
2508 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2509 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2510 MODULE_LICENSE("GPL");