ide: fix regression caused by ide_device_{get,put}() addition (take 2)
[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 IDETAPE_VERSION "1.20"
19
20 #include <linux/module.h>
21 #include <linux/types.h>
22 #include <linux/string.h>
23 #include <linux/kernel.h>
24 #include <linux/delay.h>
25 #include <linux/timer.h>
26 #include <linux/mm.h>
27 #include <linux/interrupt.h>
28 #include <linux/jiffies.h>
29 #include <linux/major.h>
30 #include <linux/errno.h>
31 #include <linux/genhd.h>
32 #include <linux/slab.h>
33 #include <linux/pci.h>
34 #include <linux/ide.h>
35 #include <linux/smp_lock.h>
36 #include <linux/completion.h>
37 #include <linux/bitops.h>
38 #include <linux/mutex.h>
39 #include <scsi/scsi.h>
40
41 #include <asm/byteorder.h>
42 #include <linux/irq.h>
43 #include <linux/uaccess.h>
44 #include <linux/io.h>
45 #include <asm/unaligned.h>
46 #include <linux/mtio.h>
47
48 enum {
49         /* output errors only */
50         DBG_ERR =               (1 << 0),
51         /* output all sense key/asc */
52         DBG_SENSE =             (1 << 1),
53         /* info regarding all chrdev-related procedures */
54         DBG_CHRDEV =            (1 << 2),
55         /* all remaining procedures */
56         DBG_PROCS =             (1 << 3),
57         /* buffer alloc info (pc_stack & rq_stack) */
58         DBG_PCRQ_STACK =        (1 << 4),
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  * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
85  * bytes. This is used for several packet commands (Not for READ/WRITE commands)
86  */
87 #define IDETAPE_PC_BUFFER_SIZE          256
88
89 /*
90  *      In various places in the driver, we need to allocate storage
91  *      for packet commands and requests, which will remain valid while
92  *      we leave the driver to wait for an interrupt or a timeout event.
93  */
94 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
95
96 /*
97  * Some drives (for example, Seagate STT3401A Travan) require a very long
98  * timeout, because they don't return an interrupt or clear their busy bit
99  * until after the command completes (even retension commands).
100  */
101 #define IDETAPE_WAIT_CMD                (900*HZ)
102
103 /*
104  * The following parameter is used to select the point in the internal tape fifo
105  * in which we will start to refill the buffer. Decreasing the following
106  * parameter will improve the system's latency and interactive response, while
107  * using a high value might improve system throughput.
108  */
109 #define IDETAPE_FIFO_THRESHOLD          2
110
111 /*
112  * DSC polling parameters.
113  *
114  * Polling for DSC (a single bit in the status register) is a very important
115  * function in ide-tape. There are two cases in which we poll for DSC:
116  *
117  * 1. Before a read/write packet command, to ensure that we can transfer data
118  * from/to the tape's data buffers, without causing an actual media access.
119  * In case the tape is not ready yet, we take out our request from the device
120  * request queue, so that ide.c could service requests from the other device
121  * on the same interface in the meantime.
122  *
123  * 2. After the successful initialization of a "media access packet command",
124  * which is a command that can take a long time to complete (the interval can
125  * range from several seconds to even an hour). Again, we postpone our request
126  * in the middle to free the bus for the other device. The polling frequency
127  * here should be lower than the read/write frequency since those media access
128  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
129  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
130  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
131  *
132  * We also set a timeout for the timer, in case something goes wrong. The
133  * timeout should be longer then the maximum execution time of a tape operation.
134  */
135
136 /* DSC timings. */
137 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
138 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
139 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
140 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
141 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
142 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
143 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
144
145 /*************************** End of tunable parameters ***********************/
146
147 /* tape directions */
148 enum {
149         IDETAPE_DIR_NONE  = (1 << 0),
150         IDETAPE_DIR_READ  = (1 << 1),
151         IDETAPE_DIR_WRITE = (1 << 2),
152 };
153
154 struct idetape_bh {
155         u32 b_size;
156         atomic_t b_count;
157         struct idetape_bh *b_reqnext;
158         char *b_data;
159 };
160
161 /* Tape door status */
162 #define DOOR_UNLOCKED                   0
163 #define DOOR_LOCKED                     1
164 #define DOOR_EXPLICITLY_LOCKED          2
165
166 /* Some defines for the SPACE command */
167 #define IDETAPE_SPACE_OVER_FILEMARK     1
168 #define IDETAPE_SPACE_TO_EOD            3
169
170 /* Some defines for the LOAD UNLOAD command */
171 #define IDETAPE_LU_LOAD_MASK            1
172 #define IDETAPE_LU_RETENSION_MASK       2
173 #define IDETAPE_LU_EOT_MASK             4
174
175 /*
176  * Special requests for our block device strategy routine.
177  *
178  * In order to service a character device command, we add special requests to
179  * the tail of our block device request queue and wait for their completion.
180  */
181
182 enum {
183         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
184         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
185         REQ_IDETAPE_READ        = (1 << 2),
186         REQ_IDETAPE_WRITE       = (1 << 3),
187 };
188
189 /* Error codes returned in rq->errors to the higher part of the driver. */
190 #define IDETAPE_ERROR_GENERAL           101
191 #define IDETAPE_ERROR_FILEMARK          102
192 #define IDETAPE_ERROR_EOD               103
193
194 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
195 #define IDETAPE_BLOCK_DESCRIPTOR        0
196 #define IDETAPE_CAPABILITIES_PAGE       0x2a
197
198 /*
199  * Most of our global data which we need to save even as we leave the driver due
200  * to an interrupt or a timer event is stored in the struct defined below.
201  */
202 typedef struct ide_tape_obj {
203         ide_drive_t     *drive;
204         ide_driver_t    *driver;
205         struct gendisk  *disk;
206         struct kref     kref;
207
208         /*
209          *      Since a typical character device operation requires more
210          *      than one packet command, we provide here enough memory
211          *      for the maximum of interconnected packet commands.
212          *      The packet commands are stored in the circular array pc_stack.
213          *      pc_stack_index points to the last used entry, and warps around
214          *      to the start when we get to the last array entry.
215          *
216          *      pc points to the current processed packet command.
217          *
218          *      failed_pc points to the last failed packet command, or contains
219          *      NULL if we do not need to retry any packet command. This is
220          *      required since an additional packet command is needed before the
221          *      retry, to get detailed information on what went wrong.
222          */
223         /* Current packet command */
224         struct ide_atapi_pc *pc;
225         /* Last failed packet command */
226         struct ide_atapi_pc *failed_pc;
227         /* Packet command stack */
228         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
229         /* Next free packet command storage space */
230         int pc_stack_index;
231         struct request rq_stack[IDETAPE_PC_STACK];
232         /* We implement a circular array */
233         int rq_stack_index;
234
235         /*
236          * DSC polling variables.
237          *
238          * While polling for DSC we use postponed_rq to postpone the current
239          * request so that ide.c will be able to service pending requests on the
240          * other device. Note that at most we will have only one DSC (usually
241          * data transfer) request in the device request queue.
242          */
243         struct request *postponed_rq;
244         /* The time in which we started polling for DSC */
245         unsigned long dsc_polling_start;
246         /* Timer used to poll for dsc */
247         struct timer_list dsc_timer;
248         /* Read/Write dsc polling frequency */
249         unsigned long best_dsc_rw_freq;
250         unsigned long dsc_poll_freq;
251         unsigned long dsc_timeout;
252
253         /* Read position information */
254         u8 partition;
255         /* Current block */
256         unsigned int first_frame;
257
258         /* Last error information */
259         u8 sense_key, asc, ascq;
260
261         /* Character device operation */
262         unsigned int minor;
263         /* device name */
264         char name[4];
265         /* Current character device data transfer direction */
266         u8 chrdev_dir;
267
268         /* tape block size, usually 512 or 1024 bytes */
269         unsigned short blk_size;
270         int user_bs_factor;
271
272         /* Copy of the tape's Capabilities and Mechanical Page */
273         u8 caps[20];
274
275         /*
276          * Active data transfer request parameters.
277          *
278          * At most, there is only one ide-tape originated data transfer request
279          * in the device request queue. This allows ide.c to easily service
280          * requests from the other device when we postpone our active request.
281          */
282
283         /* Data buffer size chosen based on the tape's recommendation */
284         int buffer_size;
285         /* merge buffer */
286         struct idetape_bh *merge_bh;
287         /* size of the merge buffer */
288         int merge_bh_size;
289         /* pointer to current buffer head within the merge buffer */
290         struct idetape_bh *bh;
291         char *b_data;
292         int b_count;
293
294         int pages_per_buffer;
295         /* Wasted space in each stage */
296         int excess_bh_size;
297
298         /* protects the ide-tape queue */
299         spinlock_t lock;
300
301         /* Measures average tape speed */
302         unsigned long avg_time;
303         int avg_size;
304         int avg_speed;
305
306         /* the door is currently locked */
307         int door_locked;
308         /* the tape hardware is write protected */
309         char drv_write_prot;
310         /* the tape is write protected (hardware or opened as read-only) */
311         char write_prot;
312
313         u32 debug_mask;
314 } idetape_tape_t;
315
316 static DEFINE_MUTEX(idetape_ref_mutex);
317
318 static struct class *idetape_sysfs_class;
319
320 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
321
322 #define ide_tape_g(disk) \
323         container_of((disk)->private_data, struct ide_tape_obj, driver)
324
325 static void ide_tape_release(struct kref *);
326
327 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
328 {
329         struct ide_tape_obj *tape = NULL;
330
331         mutex_lock(&idetape_ref_mutex);
332         tape = ide_tape_g(disk);
333         if (tape) {
334                 if (ide_device_get(tape->drive))
335                         tape = NULL;
336                 else
337                         kref_get(&tape->kref);
338         }
339         mutex_unlock(&idetape_ref_mutex);
340         return tape;
341 }
342
343 static void ide_tape_put(struct ide_tape_obj *tape)
344 {
345         ide_drive_t *drive = tape->drive;
346
347         mutex_lock(&idetape_ref_mutex);
348         kref_put(&tape->kref, ide_tape_release);
349         ide_device_put(drive);
350         mutex_unlock(&idetape_ref_mutex);
351 }
352
353 /*
354  * The variables below are used for the character device interface. Additional
355  * state variables are defined in our ide_drive_t structure.
356  */
357 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
358
359 #define ide_tape_f(file) ((file)->private_data)
360
361 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
362 {
363         struct ide_tape_obj *tape = NULL;
364
365         mutex_lock(&idetape_ref_mutex);
366         tape = idetape_devs[i];
367         if (tape)
368                 kref_get(&tape->kref);
369         mutex_unlock(&idetape_ref_mutex);
370         return tape;
371 }
372
373 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
374                                   unsigned int bcount)
375 {
376         struct idetape_bh *bh = pc->bh;
377         int count;
378
379         while (bcount) {
380                 if (bh == NULL) {
381                         printk(KERN_ERR "ide-tape: bh == NULL in "
382                                 "idetape_input_buffers\n");
383                         ide_pad_transfer(drive, 0, bcount);
384                         return;
385                 }
386                 count = min(
387                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
388                         bcount);
389                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
390                                         atomic_read(&bh->b_count), count);
391                 bcount -= count;
392                 atomic_add(count, &bh->b_count);
393                 if (atomic_read(&bh->b_count) == bh->b_size) {
394                         bh = bh->b_reqnext;
395                         if (bh)
396                                 atomic_set(&bh->b_count, 0);
397                 }
398         }
399         pc->bh = bh;
400 }
401
402 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
403                                    unsigned int bcount)
404 {
405         struct idetape_bh *bh = pc->bh;
406         int count;
407
408         while (bcount) {
409                 if (bh == NULL) {
410                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
411                                         __func__);
412                         return;
413                 }
414                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
415                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
416                 bcount -= count;
417                 pc->b_data += count;
418                 pc->b_count -= count;
419                 if (!pc->b_count) {
420                         bh = bh->b_reqnext;
421                         pc->bh = bh;
422                         if (bh) {
423                                 pc->b_data = bh->b_data;
424                                 pc->b_count = atomic_read(&bh->b_count);
425                         }
426                 }
427         }
428 }
429
430 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
431 {
432         struct idetape_bh *bh = pc->bh;
433         int count;
434         unsigned int bcount = pc->xferred;
435
436         if (pc->flags & PC_FLAG_WRITING)
437                 return;
438         while (bcount) {
439                 if (bh == NULL) {
440                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
441                                         __func__);
442                         return;
443                 }
444                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
445                 atomic_set(&bh->b_count, count);
446                 if (atomic_read(&bh->b_count) == bh->b_size)
447                         bh = bh->b_reqnext;
448                 bcount -= count;
449         }
450         pc->bh = bh;
451 }
452
453 /*
454  *      idetape_next_pc_storage returns a pointer to a place in which we can
455  *      safely store a packet command, even though we intend to leave the
456  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
457  *      commands is allocated at initialization time.
458  */
459 static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
460 {
461         idetape_tape_t *tape = drive->driver_data;
462
463         debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
464
465         if (tape->pc_stack_index == IDETAPE_PC_STACK)
466                 tape->pc_stack_index = 0;
467         return (&tape->pc_stack[tape->pc_stack_index++]);
468 }
469
470 /*
471  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
472  *      Since we queue packet commands in the request queue, we need to
473  *      allocate a request, along with the allocation of a packet command.
474  */
475
476 /**************************************************************
477  *                                                            *
478  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
479  *  followed later on by kfree().   -ml                       *
480  *                                                            *
481  **************************************************************/
482
483 static struct request *idetape_next_rq_storage(ide_drive_t *drive)
484 {
485         idetape_tape_t *tape = drive->driver_data;
486
487         debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
488
489         if (tape->rq_stack_index == IDETAPE_PC_STACK)
490                 tape->rq_stack_index = 0;
491         return (&tape->rq_stack[tape->rq_stack_index++]);
492 }
493
494 /*
495  * called on each failed packet command retry to analyze the request sense. We
496  * currently do not utilize this information.
497  */
498 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
499 {
500         idetape_tape_t *tape = drive->driver_data;
501         struct ide_atapi_pc *pc = tape->failed_pc;
502
503         tape->sense_key = sense[2] & 0xF;
504         tape->asc       = sense[12];
505         tape->ascq      = sense[13];
506
507         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
508                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
509
510         /* Correct pc->xferred by asking the tape.       */
511         if (pc->flags & PC_FLAG_DMA_ERROR) {
512                 pc->xferred = pc->req_xfer -
513                         tape->blk_size *
514                         get_unaligned_be32(&sense[3]);
515                 idetape_update_buffers(drive, pc);
516         }
517
518         /*
519          * If error was the result of a zero-length read or write command,
520          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
521          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
522          */
523         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
524             /* length == 0 */
525             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
526                 if (tape->sense_key == 5) {
527                         /* don't report an error, everything's ok */
528                         pc->error = 0;
529                         /* don't retry read/write */
530                         pc->flags |= PC_FLAG_ABORT;
531                 }
532         }
533         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
534                 pc->error = IDETAPE_ERROR_FILEMARK;
535                 pc->flags |= PC_FLAG_ABORT;
536         }
537         if (pc->c[0] == WRITE_6) {
538                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
539                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
540                         pc->error = IDETAPE_ERROR_EOD;
541                         pc->flags |= PC_FLAG_ABORT;
542                 }
543         }
544         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
545                 if (tape->sense_key == 8) {
546                         pc->error = IDETAPE_ERROR_EOD;
547                         pc->flags |= PC_FLAG_ABORT;
548                 }
549                 if (!(pc->flags & PC_FLAG_ABORT) &&
550                     pc->xferred)
551                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
552         }
553 }
554
555 /* Free data buffers completely. */
556 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
557 {
558         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
559
560         while (bh) {
561                 u32 size = bh->b_size;
562
563                 while (size) {
564                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
565
566                         if (bh->b_data)
567                                 free_pages((unsigned long)bh->b_data, order);
568
569                         size &= (order-1);
570                         bh->b_data += (1 << order) * PAGE_SIZE;
571                 }
572                 prev_bh = bh;
573                 bh = bh->b_reqnext;
574                 kfree(prev_bh);
575         }
576 }
577
578 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
579 {
580         struct request *rq = HWGROUP(drive)->rq;
581         idetape_tape_t *tape = drive->driver_data;
582         unsigned long flags;
583         int error;
584
585         debug_log(DBG_PROCS, "Enter %s\n", __func__);
586
587         switch (uptodate) {
588         case 0: error = IDETAPE_ERROR_GENERAL; break;
589         case 1: error = 0; break;
590         default: error = uptodate;
591         }
592         rq->errors = error;
593         if (error)
594                 tape->failed_pc = NULL;
595
596         if (!blk_special_request(rq)) {
597                 ide_end_request(drive, uptodate, nr_sects);
598                 return 0;
599         }
600
601         spin_lock_irqsave(&tape->lock, flags);
602
603         ide_end_drive_cmd(drive, 0, 0);
604
605         spin_unlock_irqrestore(&tape->lock, flags);
606         return 0;
607 }
608
609 static void ide_tape_callback(ide_drive_t *drive)
610 {
611         idetape_tape_t *tape = drive->driver_data;
612         struct ide_atapi_pc *pc = tape->pc;
613         int uptodate = pc->error ? 0 : 1;
614
615         debug_log(DBG_PROCS, "Enter %s\n", __func__);
616
617         if (tape->failed_pc == pc)
618                 tape->failed_pc = NULL;
619
620         if (pc->c[0] == REQUEST_SENSE) {
621                 if (uptodate)
622                         idetape_analyze_error(drive, pc->buf);
623                 else
624                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
625                                         "itself - Aborting request!\n");
626         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
627                 struct request *rq = drive->hwif->hwgroup->rq;
628                 int blocks = pc->xferred / tape->blk_size;
629
630                 tape->avg_size += blocks * tape->blk_size;
631
632                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
633                         tape->avg_speed = tape->avg_size * HZ /
634                                 (jiffies - tape->avg_time) / 1024;
635                         tape->avg_size = 0;
636                         tape->avg_time = jiffies;
637                 }
638
639                 tape->first_frame += blocks;
640                 rq->current_nr_sectors -= blocks;
641
642                 if (pc->error)
643                         uptodate = pc->error;
644         } else if (pc->c[0] == READ_POSITION && uptodate) {
645                 u8 *readpos = tape->pc->buf;
646
647                 debug_log(DBG_SENSE, "BOP - %s\n",
648                                 (readpos[0] & 0x80) ? "Yes" : "No");
649                 debug_log(DBG_SENSE, "EOP - %s\n",
650                                 (readpos[0] & 0x40) ? "Yes" : "No");
651
652                 if (readpos[0] & 0x4) {
653                         printk(KERN_INFO "ide-tape: Block location is unknown"
654                                          "to the tape\n");
655                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
656                         uptodate = 0;
657                 } else {
658                         debug_log(DBG_SENSE, "Block Location - %u\n",
659                                         be32_to_cpup((__be32 *)&readpos[4]));
660
661                         tape->partition = readpos[1];
662                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
663                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
664                 }
665         }
666
667         idetape_end_request(drive, uptodate, 0);
668 }
669
670 static void idetape_init_pc(struct ide_atapi_pc *pc)
671 {
672         memset(pc->c, 0, 12);
673         pc->retries = 0;
674         pc->flags = 0;
675         pc->req_xfer = 0;
676         pc->buf = pc->pc_buf;
677         pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
678         pc->bh = NULL;
679         pc->b_data = NULL;
680 }
681
682 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
683 {
684         idetape_init_pc(pc);
685         pc->c[0] = REQUEST_SENSE;
686         pc->c[4] = 20;
687         pc->req_xfer = 20;
688 }
689
690 static void idetape_init_rq(struct request *rq, u8 cmd)
691 {
692         blk_rq_init(NULL, rq);
693         rq->cmd_type = REQ_TYPE_SPECIAL;
694         rq->cmd[13] = cmd;
695 }
696
697 /*
698  * Generate a new packet command request in front of the request queue, before
699  * the current request, so that it will be processed immediately, on the next
700  * pass through the driver. The function below is called from the request
701  * handling part of the driver (the "bottom" part). Safe storage for the request
702  * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
703  *
704  * Memory for those requests is pre-allocated at initialization time, and is
705  * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
706  * the maximum possible number of inter-dependent packet commands.
707  *
708  * The higher level of the driver - The ioctl handler and the character device
709  * handling functions should queue request to the lower level part and wait for
710  * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
711  */
712 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
713                                   struct request *rq)
714 {
715         struct ide_tape_obj *tape = drive->driver_data;
716
717         idetape_init_rq(rq, REQ_IDETAPE_PC1);
718         rq->cmd_flags |= REQ_PREEMPT;
719         rq->buffer = (char *) pc;
720         rq->rq_disk = tape->disk;
721         memcpy(rq->cmd, pc->c, 12);
722         ide_do_drive_cmd(drive, rq);
723 }
724
725 /*
726  *      idetape_retry_pc is called when an error was detected during the
727  *      last packet command. We queue a request sense packet command in
728  *      the head of the request list.
729  */
730 static void idetape_retry_pc(ide_drive_t *drive)
731 {
732         struct ide_atapi_pc *pc;
733         struct request *rq;
734
735         (void)ide_read_error(drive);
736         pc = idetape_next_pc_storage(drive);
737         rq = idetape_next_rq_storage(drive);
738         idetape_create_request_sense_cmd(pc);
739         set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
740         idetape_queue_pc_head(drive, pc, rq);
741 }
742
743 /*
744  * Postpone the current request so that ide.c will be able to service requests
745  * from another device on the same hwgroup while we are polling for DSC.
746  */
747 static void idetape_postpone_request(ide_drive_t *drive)
748 {
749         idetape_tape_t *tape = drive->driver_data;
750
751         debug_log(DBG_PROCS, "Enter %s\n", __func__);
752
753         tape->postponed_rq = HWGROUP(drive)->rq;
754         ide_stall_queue(drive, tape->dsc_poll_freq);
755 }
756
757 static void ide_tape_handle_dsc(ide_drive_t *drive)
758 {
759         idetape_tape_t *tape = drive->driver_data;
760
761         /* Media access command */
762         tape->dsc_polling_start = jiffies;
763         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
764         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
765         /* Allow ide.c to handle other requests */
766         idetape_postpone_request(drive);
767 }
768
769 static void ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
770                                 unsigned int bcount, int write)
771 {
772         if (write)
773                 idetape_output_buffers(drive, pc, bcount);
774         else
775                 idetape_input_buffers(drive, pc, bcount);
776 }
777
778 /*
779  * This is the usual interrupt handler which will be called during a packet
780  * command. We will transfer some of the data (as requested by the drive) and
781  * will re-point interrupt handler to us. When data transfer is finished, we
782  * will act according to the algorithm described before
783  * idetape_issue_pc.
784  */
785 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
786 {
787         idetape_tape_t *tape = drive->driver_data;
788
789         return ide_pc_intr(drive, tape->pc, idetape_pc_intr, IDETAPE_WAIT_CMD,
790                            NULL, idetape_update_buffers, idetape_retry_pc,
791                            ide_tape_handle_dsc, ide_tape_io_buffers);
792 }
793
794 /*
795  * Packet Command Interface
796  *
797  * The current Packet Command is available in tape->pc, and will not change
798  * until we finish handling it. Each packet command is associated with a
799  * callback function that will be called when the command is finished.
800  *
801  * The handling will be done in three stages:
802  *
803  * 1. idetape_issue_pc will send the packet command to the drive, and will set
804  * the interrupt handler to idetape_pc_intr.
805  *
806  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
807  * repeated until the device signals us that no more interrupts will be issued.
808  *
809  * 3. ATAPI Tape media access commands have immediate status with a delayed
810  * process. In case of a successful initiation of a media access packet command,
811  * the DSC bit will be set when the actual execution of the command is finished.
812  * Since the tape drive will not issue an interrupt, we have to poll for this
813  * event. In this case, we define the request as "low priority request" by
814  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
815  * exit the driver.
816  *
817  * ide.c will then give higher priority to requests which originate from the
818  * other device, until will change rq_status to RQ_ACTIVE.
819  *
820  * 4. When the packet command is finished, it will be checked for errors.
821  *
822  * 5. In case an error was found, we queue a request sense packet command in
823  * front of the request queue and retry the operation up to
824  * IDETAPE_MAX_PC_RETRIES times.
825  *
826  * 6. In case no error was found, or we decided to give up and not to retry
827  * again, the callback function will be called and then we will handle the next
828  * request.
829  */
830 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
831 {
832         idetape_tape_t *tape = drive->driver_data;
833
834         return ide_transfer_pc(drive, tape->pc, idetape_pc_intr,
835                                IDETAPE_WAIT_CMD, NULL);
836 }
837
838 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
839                 struct ide_atapi_pc *pc)
840 {
841         idetape_tape_t *tape = drive->driver_data;
842
843         if (tape->pc->c[0] == REQUEST_SENSE &&
844             pc->c[0] == REQUEST_SENSE) {
845                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
846                         "Two request sense in serial were issued\n");
847         }
848
849         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
850                 tape->failed_pc = pc;
851         /* Set the current packet command */
852         tape->pc = pc;
853
854         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
855                 (pc->flags & PC_FLAG_ABORT)) {
856                 /*
857                  * We will "abort" retrying a packet command in case legitimate
858                  * error code was received (crossing a filemark, or end of the
859                  * media, for example).
860                  */
861                 if (!(pc->flags & PC_FLAG_ABORT)) {
862                         if (!(pc->c[0] == TEST_UNIT_READY &&
863                               tape->sense_key == 2 && tape->asc == 4 &&
864                              (tape->ascq == 1 || tape->ascq == 8))) {
865                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
866                                                 "pc = %2x, key = %2x, "
867                                                 "asc = %2x, ascq = %2x\n",
868                                                 tape->name, pc->c[0],
869                                                 tape->sense_key, tape->asc,
870                                                 tape->ascq);
871                         }
872                         /* Giving up */
873                         pc->error = IDETAPE_ERROR_GENERAL;
874                 }
875                 tape->failed_pc = NULL;
876                 drive->pc_callback(drive);
877                 return ide_stopped;
878         }
879         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
880
881         pc->retries++;
882
883         return ide_issue_pc(drive, pc, idetape_transfer_pc,
884                             IDETAPE_WAIT_CMD, NULL);
885 }
886
887 /* A mode sense command is used to "sense" tape parameters. */
888 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
889 {
890         idetape_init_pc(pc);
891         pc->c[0] = MODE_SENSE;
892         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
893                 /* DBD = 1 - Don't return block descriptors */
894                 pc->c[1] = 8;
895         pc->c[2] = page_code;
896         /*
897          * Changed pc->c[3] to 0 (255 will at best return unused info).
898          *
899          * For SCSI this byte is defined as subpage instead of high byte
900          * of length and some IDE drives seem to interpret it this way
901          * and return an error when 255 is used.
902          */
903         pc->c[3] = 0;
904         /* We will just discard data in that case */
905         pc->c[4] = 255;
906         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
907                 pc->req_xfer = 12;
908         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
909                 pc->req_xfer = 24;
910         else
911                 pc->req_xfer = 50;
912 }
913
914 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
915 {
916         ide_hwif_t *hwif = drive->hwif;
917         idetape_tape_t *tape = drive->driver_data;
918         struct ide_atapi_pc *pc = tape->pc;
919         u8 stat;
920
921         stat = hwif->tp_ops->read_status(hwif);
922
923         if (stat & SEEK_STAT) {
924                 if (stat & ERR_STAT) {
925                         /* Error detected */
926                         if (pc->c[0] != TEST_UNIT_READY)
927                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
928                                                 tape->name);
929                         /* Retry operation */
930                         idetape_retry_pc(drive);
931                         return ide_stopped;
932                 }
933                 pc->error = 0;
934         } else {
935                 pc->error = IDETAPE_ERROR_GENERAL;
936                 tape->failed_pc = NULL;
937         }
938         drive->pc_callback(drive);
939         return ide_stopped;
940 }
941
942 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
943                                    struct ide_atapi_pc *pc, struct request *rq,
944                                    u8 opcode)
945 {
946         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
947         unsigned int length = rq->current_nr_sectors;
948
949         idetape_init_pc(pc);
950         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
951         pc->c[1] = 1;
952         pc->bh = bh;
953         pc->buf = NULL;
954         pc->buf_size = length * tape->blk_size;
955         pc->req_xfer = pc->buf_size;
956         if (pc->req_xfer == tape->buffer_size)
957                 pc->flags |= PC_FLAG_DMA_OK;
958
959         if (opcode == READ_6) {
960                 pc->c[0] = READ_6;
961                 atomic_set(&bh->b_count, 0);
962         } else if (opcode == WRITE_6) {
963                 pc->c[0] = WRITE_6;
964                 pc->flags |= PC_FLAG_WRITING;
965                 pc->b_data = bh->b_data;
966                 pc->b_count = atomic_read(&bh->b_count);
967         }
968
969         memcpy(rq->cmd, pc->c, 12);
970 }
971
972 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
973                                           struct request *rq, sector_t block)
974 {
975         ide_hwif_t *hwif = drive->hwif;
976         idetape_tape_t *tape = drive->driver_data;
977         struct ide_atapi_pc *pc = NULL;
978         struct request *postponed_rq = tape->postponed_rq;
979         u8 stat;
980
981         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
982                         " current_nr_sectors: %d\n",
983                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
984
985         if (!blk_special_request(rq)) {
986                 /* We do not support buffer cache originated requests. */
987                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
988                         "request queue (%d)\n", drive->name, rq->cmd_type);
989                 ide_end_request(drive, 0, 0);
990                 return ide_stopped;
991         }
992
993         /* Retry a failed packet command */
994         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE) {
995                 pc = tape->failed_pc;
996                 goto out;
997         }
998
999         if (postponed_rq != NULL)
1000                 if (rq != postponed_rq) {
1001                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1002                                         "Two DSC requests were queued\n");
1003                         idetape_end_request(drive, 0, 0);
1004                         return ide_stopped;
1005                 }
1006
1007         tape->postponed_rq = NULL;
1008
1009         /*
1010          * If the tape is still busy, postpone our request and service
1011          * the other device meanwhile.
1012          */
1013         stat = hwif->tp_ops->read_status(hwif);
1014
1015         if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
1016                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
1017
1018         if (drive->post_reset == 1) {
1019                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
1020                 drive->post_reset = 0;
1021         }
1022
1023         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
1024             (stat & SEEK_STAT) == 0) {
1025                 if (postponed_rq == NULL) {
1026                         tape->dsc_polling_start = jiffies;
1027                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1028                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1029                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1030                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1031                                 tape->name);
1032                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
1033                                 idetape_media_access_finished(drive);
1034                                 return ide_stopped;
1035                         } else {
1036                                 return ide_do_reset(drive);
1037                         }
1038                 } else if (time_after(jiffies,
1039                                         tape->dsc_polling_start +
1040                                         IDETAPE_DSC_MA_THRESHOLD))
1041                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1042                 idetape_postpone_request(drive);
1043                 return ide_stopped;
1044         }
1045         if (rq->cmd[13] & REQ_IDETAPE_READ) {
1046                 pc = idetape_next_pc_storage(drive);
1047                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
1048                 goto out;
1049         }
1050         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
1051                 pc = idetape_next_pc_storage(drive);
1052                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
1053                 goto out;
1054         }
1055         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
1056                 pc = (struct ide_atapi_pc *) rq->buffer;
1057                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
1058                 rq->cmd[13] |= REQ_IDETAPE_PC2;
1059                 goto out;
1060         }
1061         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
1062                 idetape_media_access_finished(drive);
1063                 return ide_stopped;
1064         }
1065         BUG();
1066
1067 out:
1068         return idetape_issue_pc(drive, pc);
1069 }
1070
1071 /*
1072  * The function below uses __get_free_pages to allocate a data buffer of size
1073  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
1074  * much as possible.
1075  *
1076  * It returns a pointer to the newly allocated buffer, or NULL in case of
1077  * failure.
1078  */
1079 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
1080                                                   int full, int clear)
1081 {
1082         struct idetape_bh *prev_bh, *bh, *merge_bh;
1083         int pages = tape->pages_per_buffer;
1084         unsigned int order, b_allocd;
1085         char *b_data = NULL;
1086
1087         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1088         bh = merge_bh;
1089         if (bh == NULL)
1090                 goto abort;
1091
1092         order = fls(pages) - 1;
1093         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1094         if (!bh->b_data)
1095                 goto abort;
1096         b_allocd = (1 << order) * PAGE_SIZE;
1097         pages &= (order-1);
1098
1099         if (clear)
1100                 memset(bh->b_data, 0, b_allocd);
1101         bh->b_reqnext = NULL;
1102         bh->b_size = b_allocd;
1103         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1104
1105         while (pages) {
1106                 order = fls(pages) - 1;
1107                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1108                 if (!b_data)
1109                         goto abort;
1110                 b_allocd = (1 << order) * PAGE_SIZE;
1111
1112                 if (clear)
1113                         memset(b_data, 0, b_allocd);
1114
1115                 /* newly allocated page frames below buffer header or ...*/
1116                 if (bh->b_data == b_data + b_allocd) {
1117                         bh->b_size += b_allocd;
1118                         bh->b_data -= b_allocd;
1119                         if (full)
1120                                 atomic_add(b_allocd, &bh->b_count);
1121                         continue;
1122                 }
1123                 /* they are above the header */
1124                 if (b_data == bh->b_data + bh->b_size) {
1125                         bh->b_size += b_allocd;
1126                         if (full)
1127                                 atomic_add(b_allocd, &bh->b_count);
1128                         continue;
1129                 }
1130                 prev_bh = bh;
1131                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1132                 if (!bh) {
1133                         free_pages((unsigned long) b_data, order);
1134                         goto abort;
1135                 }
1136                 bh->b_reqnext = NULL;
1137                 bh->b_data = b_data;
1138                 bh->b_size = b_allocd;
1139                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1140                 prev_bh->b_reqnext = bh;
1141
1142                 pages &= (order-1);
1143         }
1144
1145         bh->b_size -= tape->excess_bh_size;
1146         if (full)
1147                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1148         return merge_bh;
1149 abort:
1150         ide_tape_kfree_buffer(tape);
1151         return NULL;
1152 }
1153
1154 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1155                                         const char __user *buf, int n)
1156 {
1157         struct idetape_bh *bh = tape->bh;
1158         int count;
1159         int ret = 0;
1160
1161         while (n) {
1162                 if (bh == NULL) {
1163                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1164                                         __func__);
1165                         return 1;
1166                 }
1167                 count = min((unsigned int)
1168                                 (bh->b_size - atomic_read(&bh->b_count)),
1169                                 (unsigned int)n);
1170                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1171                                 count))
1172                         ret = 1;
1173                 n -= count;
1174                 atomic_add(count, &bh->b_count);
1175                 buf += count;
1176                 if (atomic_read(&bh->b_count) == bh->b_size) {
1177                         bh = bh->b_reqnext;
1178                         if (bh)
1179                                 atomic_set(&bh->b_count, 0);
1180                 }
1181         }
1182         tape->bh = bh;
1183         return ret;
1184 }
1185
1186 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1187                                       int n)
1188 {
1189         struct idetape_bh *bh = tape->bh;
1190         int count;
1191         int ret = 0;
1192
1193         while (n) {
1194                 if (bh == NULL) {
1195                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1196                                         __func__);
1197                         return 1;
1198                 }
1199                 count = min(tape->b_count, n);
1200                 if  (copy_to_user(buf, tape->b_data, count))
1201                         ret = 1;
1202                 n -= count;
1203                 tape->b_data += count;
1204                 tape->b_count -= count;
1205                 buf += count;
1206                 if (!tape->b_count) {
1207                         bh = bh->b_reqnext;
1208                         tape->bh = bh;
1209                         if (bh) {
1210                                 tape->b_data = bh->b_data;
1211                                 tape->b_count = atomic_read(&bh->b_count);
1212                         }
1213                 }
1214         }
1215         return ret;
1216 }
1217
1218 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1219 {
1220         struct idetape_bh *bh = tape->merge_bh;
1221         tape->bh = tape->merge_bh;
1222
1223         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1224                 atomic_set(&bh->b_count, 0);
1225         else {
1226                 tape->b_data = bh->b_data;
1227                 tape->b_count = atomic_read(&bh->b_count);
1228         }
1229 }
1230
1231 /*
1232  * Write a filemark if write_filemark=1. Flush the device buffers without
1233  * writing a filemark otherwise.
1234  */
1235 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1236                 struct ide_atapi_pc *pc, int write_filemark)
1237 {
1238         idetape_init_pc(pc);
1239         pc->c[0] = WRITE_FILEMARKS;
1240         pc->c[4] = write_filemark;
1241         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1242 }
1243
1244 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1245 {
1246         idetape_init_pc(pc);
1247         pc->c[0] = TEST_UNIT_READY;
1248 }
1249
1250 /*
1251  * We add a special packet command request to the tail of the request queue, and
1252  * wait for it to be serviced. This is not to be called from within the request
1253  * handling part of the driver! We allocate here data on the stack and it is
1254  * valid until the request is finished. This is not the case for the bottom part
1255  * of the driver, where we are always leaving the functions to wait for an
1256  * interrupt or a timer event.
1257  *
1258  * From the bottom part of the driver, we should allocate safe memory using
1259  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1260  * to the request list without waiting for it to be serviced! In that case, we
1261  * usually use idetape_queue_pc_head().
1262  */
1263 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1264 {
1265         struct ide_tape_obj *tape = drive->driver_data;
1266         struct request *rq;
1267         int error;
1268
1269         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1270         rq->cmd_type = REQ_TYPE_SPECIAL;
1271         rq->cmd[13] = REQ_IDETAPE_PC1;
1272         rq->buffer = (char *)pc;
1273         memcpy(rq->cmd, pc->c, 12);
1274         error = blk_execute_rq(drive->queue, tape->disk, rq, 0);
1275         blk_put_request(rq);
1276         return error;
1277 }
1278
1279 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1280                 struct ide_atapi_pc *pc, int cmd)
1281 {
1282         idetape_init_pc(pc);
1283         pc->c[0] = START_STOP;
1284         pc->c[4] = cmd;
1285         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1286 }
1287
1288 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1289 {
1290         idetape_tape_t *tape = drive->driver_data;
1291         struct ide_atapi_pc pc;
1292         int load_attempted = 0;
1293
1294         /* Wait for the tape to become ready */
1295         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1296         timeout += jiffies;
1297         while (time_before(jiffies, timeout)) {
1298                 idetape_create_test_unit_ready_cmd(&pc);
1299                 if (!idetape_queue_pc_tail(drive, &pc))
1300                         return 0;
1301                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1302                     || (tape->asc == 0x3A)) {
1303                         /* no media */
1304                         if (load_attempted)
1305                                 return -ENOMEDIUM;
1306                         idetape_create_load_unload_cmd(drive, &pc,
1307                                                         IDETAPE_LU_LOAD_MASK);
1308                         idetape_queue_pc_tail(drive, &pc);
1309                         load_attempted = 1;
1310                 /* not about to be ready */
1311                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1312                              (tape->ascq == 1 || tape->ascq == 8)))
1313                         return -EIO;
1314                 msleep(100);
1315         }
1316         return -EIO;
1317 }
1318
1319 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1320 {
1321         struct ide_atapi_pc pc;
1322         int rc;
1323
1324         idetape_create_write_filemark_cmd(drive, &pc, 0);
1325         rc = idetape_queue_pc_tail(drive, &pc);
1326         if (rc)
1327                 return rc;
1328         idetape_wait_ready(drive, 60 * 5 * HZ);
1329         return 0;
1330 }
1331
1332 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1333 {
1334         idetape_init_pc(pc);
1335         pc->c[0] = READ_POSITION;
1336         pc->req_xfer = 20;
1337 }
1338
1339 static int idetape_read_position(ide_drive_t *drive)
1340 {
1341         idetape_tape_t *tape = drive->driver_data;
1342         struct ide_atapi_pc pc;
1343         int position;
1344
1345         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1346
1347         idetape_create_read_position_cmd(&pc);
1348         if (idetape_queue_pc_tail(drive, &pc))
1349                 return -1;
1350         position = tape->first_frame;
1351         return position;
1352 }
1353
1354 static void idetape_create_locate_cmd(ide_drive_t *drive,
1355                 struct ide_atapi_pc *pc,
1356                 unsigned int block, u8 partition, int skip)
1357 {
1358         idetape_init_pc(pc);
1359         pc->c[0] = POSITION_TO_ELEMENT;
1360         pc->c[1] = 2;
1361         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1362         pc->c[8] = partition;
1363         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1364 }
1365
1366 static int idetape_create_prevent_cmd(ide_drive_t *drive,
1367                 struct ide_atapi_pc *pc, int prevent)
1368 {
1369         idetape_tape_t *tape = drive->driver_data;
1370
1371         /* device supports locking according to capabilities page */
1372         if (!(tape->caps[6] & 0x01))
1373                 return 0;
1374
1375         idetape_init_pc(pc);
1376         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
1377         pc->c[4] = prevent;
1378         return 1;
1379 }
1380
1381 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1382 {
1383         idetape_tape_t *tape = drive->driver_data;
1384
1385         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1386                 return;
1387
1388         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1389         tape->merge_bh_size = 0;
1390         if (tape->merge_bh != NULL) {
1391                 ide_tape_kfree_buffer(tape);
1392                 tape->merge_bh = NULL;
1393         }
1394
1395         tape->chrdev_dir = IDETAPE_DIR_NONE;
1396 }
1397
1398 /*
1399  * Position the tape to the requested block using the LOCATE packet command.
1400  * A READ POSITION command is then issued to check where we are positioned. Like
1401  * all higher level operations, we queue the commands at the tail of the request
1402  * queue and wait for their completion.
1403  */
1404 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1405                 u8 partition, int skip)
1406 {
1407         idetape_tape_t *tape = drive->driver_data;
1408         int retval;
1409         struct ide_atapi_pc pc;
1410
1411         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1412                 __ide_tape_discard_merge_buffer(drive);
1413         idetape_wait_ready(drive, 60 * 5 * HZ);
1414         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1415         retval = idetape_queue_pc_tail(drive, &pc);
1416         if (retval)
1417                 return (retval);
1418
1419         idetape_create_read_position_cmd(&pc);
1420         return (idetape_queue_pc_tail(drive, &pc));
1421 }
1422
1423 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1424                                           int restore_position)
1425 {
1426         idetape_tape_t *tape = drive->driver_data;
1427         int seek, position;
1428
1429         __ide_tape_discard_merge_buffer(drive);
1430         if (restore_position) {
1431                 position = idetape_read_position(drive);
1432                 seek = position > 0 ? position : 0;
1433                 if (idetape_position_tape(drive, seek, 0, 0)) {
1434                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1435                                          " %s\n", tape->name, __func__);
1436                         return;
1437                 }
1438         }
1439 }
1440
1441 /*
1442  * Generate a read/write request for the block device interface and wait for it
1443  * to be serviced.
1444  */
1445 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1446                                  struct idetape_bh *bh)
1447 {
1448         idetape_tape_t *tape = drive->driver_data;
1449         struct request *rq;
1450         int ret, errors;
1451
1452         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1453
1454         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1455         rq->cmd_type = REQ_TYPE_SPECIAL;
1456         rq->cmd[13] = cmd;
1457         rq->rq_disk = tape->disk;
1458         rq->special = (void *)bh;
1459         rq->sector = tape->first_frame;
1460         rq->nr_sectors = blocks;
1461         rq->current_nr_sectors = blocks;
1462         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1463
1464         errors = rq->errors;
1465         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1466         blk_put_request(rq);
1467
1468         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1469                 return 0;
1470
1471         if (tape->merge_bh)
1472                 idetape_init_merge_buffer(tape);
1473         if (errors == IDETAPE_ERROR_GENERAL)
1474                 return -EIO;
1475         return ret;
1476 }
1477
1478 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1479 {
1480         idetape_init_pc(pc);
1481         pc->c[0] = INQUIRY;
1482         pc->c[4] = 254;
1483         pc->req_xfer = 254;
1484 }
1485
1486 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1487                 struct ide_atapi_pc *pc)
1488 {
1489         idetape_init_pc(pc);
1490         pc->c[0] = REZERO_UNIT;
1491         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1492 }
1493
1494 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1495 {
1496         idetape_init_pc(pc);
1497         pc->c[0] = ERASE;
1498         pc->c[1] = 1;
1499         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1500 }
1501
1502 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1503 {
1504         idetape_init_pc(pc);
1505         pc->c[0] = SPACE;
1506         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1507         pc->c[1] = cmd;
1508         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1509 }
1510
1511 /* Queue up a character device originated write request. */
1512 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1513 {
1514         idetape_tape_t *tape = drive->driver_data;
1515
1516         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1517
1518         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1519                                      blocks, tape->merge_bh);
1520 }
1521
1522 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1523 {
1524         idetape_tape_t *tape = drive->driver_data;
1525         int blocks, min;
1526         struct idetape_bh *bh;
1527
1528         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1529                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1530                                 " but we are not writing.\n");
1531                 return;
1532         }
1533         if (tape->merge_bh_size > tape->buffer_size) {
1534                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1535                 tape->merge_bh_size = tape->buffer_size;
1536         }
1537         if (tape->merge_bh_size) {
1538                 blocks = tape->merge_bh_size / tape->blk_size;
1539                 if (tape->merge_bh_size % tape->blk_size) {
1540                         unsigned int i;
1541
1542                         blocks++;
1543                         i = tape->blk_size - tape->merge_bh_size %
1544                                 tape->blk_size;
1545                         bh = tape->bh->b_reqnext;
1546                         while (bh) {
1547                                 atomic_set(&bh->b_count, 0);
1548                                 bh = bh->b_reqnext;
1549                         }
1550                         bh = tape->bh;
1551                         while (i) {
1552                                 if (bh == NULL) {
1553                                         printk(KERN_INFO "ide-tape: bug,"
1554                                                          " bh NULL\n");
1555                                         break;
1556                                 }
1557                                 min = min(i, (unsigned int)(bh->b_size -
1558                                                 atomic_read(&bh->b_count)));
1559                                 memset(bh->b_data + atomic_read(&bh->b_count),
1560                                                 0, min);
1561                                 atomic_add(min, &bh->b_count);
1562                                 i -= min;
1563                                 bh = bh->b_reqnext;
1564                         }
1565                 }
1566                 (void) idetape_add_chrdev_write_request(drive, blocks);
1567                 tape->merge_bh_size = 0;
1568         }
1569         if (tape->merge_bh != NULL) {
1570                 ide_tape_kfree_buffer(tape);
1571                 tape->merge_bh = NULL;
1572         }
1573         tape->chrdev_dir = IDETAPE_DIR_NONE;
1574 }
1575
1576 static int idetape_init_read(ide_drive_t *drive)
1577 {
1578         idetape_tape_t *tape = drive->driver_data;
1579         int bytes_read;
1580
1581         /* Initialize read operation */
1582         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1583                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1584                         ide_tape_flush_merge_buffer(drive);
1585                         idetape_flush_tape_buffers(drive);
1586                 }
1587                 if (tape->merge_bh || tape->merge_bh_size) {
1588                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1589                                          " 0 now\n");
1590                         tape->merge_bh_size = 0;
1591                 }
1592                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1593                 if (!tape->merge_bh)
1594                         return -ENOMEM;
1595                 tape->chrdev_dir = IDETAPE_DIR_READ;
1596
1597                 /*
1598                  * Issue a read 0 command to ensure that DSC handshake is
1599                  * switched from completion mode to buffer available mode.
1600                  * No point in issuing this if DSC overlap isn't supported, some
1601                  * drives (Seagate STT3401A) will return an error.
1602                  */
1603                 if (drive->dsc_overlap) {
1604                         bytes_read = idetape_queue_rw_tail(drive,
1605                                                         REQ_IDETAPE_READ, 0,
1606                                                         tape->merge_bh);
1607                         if (bytes_read < 0) {
1608                                 ide_tape_kfree_buffer(tape);
1609                                 tape->merge_bh = NULL;
1610                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1611                                 return bytes_read;
1612                         }
1613                 }
1614         }
1615
1616         return 0;
1617 }
1618
1619 /* called from idetape_chrdev_read() to service a chrdev read request. */
1620 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1621 {
1622         idetape_tape_t *tape = drive->driver_data;
1623
1624         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1625
1626         /* If we are at a filemark, return a read length of 0 */
1627         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1628                 return 0;
1629
1630         idetape_init_read(drive);
1631
1632         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1633                                      tape->merge_bh);
1634 }
1635
1636 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1637 {
1638         idetape_tape_t *tape = drive->driver_data;
1639         struct idetape_bh *bh;
1640         int blocks;
1641
1642         while (bcount) {
1643                 unsigned int count;
1644
1645                 bh = tape->merge_bh;
1646                 count = min(tape->buffer_size, bcount);
1647                 bcount -= count;
1648                 blocks = count / tape->blk_size;
1649                 while (count) {
1650                         atomic_set(&bh->b_count,
1651                                    min(count, (unsigned int)bh->b_size));
1652                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1653                         count -= atomic_read(&bh->b_count);
1654                         bh = bh->b_reqnext;
1655                 }
1656                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1657                                       tape->merge_bh);
1658         }
1659 }
1660
1661 /*
1662  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1663  * currently support only one partition.
1664  */
1665 static int idetape_rewind_tape(ide_drive_t *drive)
1666 {
1667         int retval;
1668         struct ide_atapi_pc pc;
1669         idetape_tape_t *tape;
1670         tape = drive->driver_data;
1671
1672         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1673
1674         idetape_create_rewind_cmd(drive, &pc);
1675         retval = idetape_queue_pc_tail(drive, &pc);
1676         if (retval)
1677                 return retval;
1678
1679         idetape_create_read_position_cmd(&pc);
1680         retval = idetape_queue_pc_tail(drive, &pc);
1681         if (retval)
1682                 return retval;
1683         return 0;
1684 }
1685
1686 /* mtio.h compatible commands should be issued to the chrdev interface. */
1687 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1688                                 unsigned long arg)
1689 {
1690         idetape_tape_t *tape = drive->driver_data;
1691         void __user *argp = (void __user *)arg;
1692
1693         struct idetape_config {
1694                 int dsc_rw_frequency;
1695                 int dsc_media_access_frequency;
1696                 int nr_stages;
1697         } config;
1698
1699         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1700
1701         switch (cmd) {
1702         case 0x0340:
1703                 if (copy_from_user(&config, argp, sizeof(config)))
1704                         return -EFAULT;
1705                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1706                 break;
1707         case 0x0350:
1708                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1709                 config.nr_stages = 1;
1710                 if (copy_to_user(argp, &config, sizeof(config)))
1711                         return -EFAULT;
1712                 break;
1713         default:
1714                 return -EIO;
1715         }
1716         return 0;
1717 }
1718
1719 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1720                                         int mt_count)
1721 {
1722         idetape_tape_t *tape = drive->driver_data;
1723         struct ide_atapi_pc pc;
1724         int retval, count = 0;
1725         int sprev = !!(tape->caps[4] & 0x20);
1726
1727         if (mt_count == 0)
1728                 return 0;
1729         if (MTBSF == mt_op || MTBSFM == mt_op) {
1730                 if (!sprev)
1731                         return -EIO;
1732                 mt_count = -mt_count;
1733         }
1734
1735         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1736                 tape->merge_bh_size = 0;
1737                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1738                         ++count;
1739                 ide_tape_discard_merge_buffer(drive, 0);
1740         }
1741
1742         switch (mt_op) {
1743         case MTFSF:
1744         case MTBSF:
1745                 idetape_create_space_cmd(&pc, mt_count - count,
1746                                          IDETAPE_SPACE_OVER_FILEMARK);
1747                 return idetape_queue_pc_tail(drive, &pc);
1748         case MTFSFM:
1749         case MTBSFM:
1750                 if (!sprev)
1751                         return -EIO;
1752                 retval = idetape_space_over_filemarks(drive, MTFSF,
1753                                                       mt_count - count);
1754                 if (retval)
1755                         return retval;
1756                 count = (MTBSFM == mt_op ? 1 : -1);
1757                 return idetape_space_over_filemarks(drive, MTFSF, count);
1758         default:
1759                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1760                                 mt_op);
1761                 return -EIO;
1762         }
1763 }
1764
1765 /*
1766  * Our character device read / write functions.
1767  *
1768  * The tape is optimized to maximize throughput when it is transferring an
1769  * integral number of the "continuous transfer limit", which is a parameter of
1770  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1771  *
1772  * As of version 1.3 of the driver, the character device provides an abstract
1773  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1774  * same backup/restore procedure is supported. The driver will internally
1775  * convert the requests to the recommended transfer unit, so that an unmatch
1776  * between the user's block size to the recommended size will only result in a
1777  * (slightly) increased driver overhead, but will no longer hit performance.
1778  * This is not applicable to Onstream.
1779  */
1780 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1781                                    size_t count, loff_t *ppos)
1782 {
1783         struct ide_tape_obj *tape = ide_tape_f(file);
1784         ide_drive_t *drive = tape->drive;
1785         ssize_t bytes_read, temp, actually_read = 0, rc;
1786         ssize_t ret = 0;
1787         u16 ctl = *(u16 *)&tape->caps[12];
1788
1789         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1790
1791         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1792                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1793                         if (count > tape->blk_size &&
1794                             (count % tape->blk_size) == 0)
1795                                 tape->user_bs_factor = count / tape->blk_size;
1796         }
1797         rc = idetape_init_read(drive);
1798         if (rc < 0)
1799                 return rc;
1800         if (count == 0)
1801                 return (0);
1802         if (tape->merge_bh_size) {
1803                 actually_read = min((unsigned int)(tape->merge_bh_size),
1804                                     (unsigned int)count);
1805                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1806                         ret = -EFAULT;
1807                 buf += actually_read;
1808                 tape->merge_bh_size -= actually_read;
1809                 count -= actually_read;
1810         }
1811         while (count >= tape->buffer_size) {
1812                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1813                 if (bytes_read <= 0)
1814                         goto finish;
1815                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1816                         ret = -EFAULT;
1817                 buf += bytes_read;
1818                 count -= bytes_read;
1819                 actually_read += bytes_read;
1820         }
1821         if (count) {
1822                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1823                 if (bytes_read <= 0)
1824                         goto finish;
1825                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1826                 if (idetape_copy_stage_to_user(tape, buf, temp))
1827                         ret = -EFAULT;
1828                 actually_read += temp;
1829                 tape->merge_bh_size = bytes_read-temp;
1830         }
1831 finish:
1832         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1833                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1834
1835                 idetape_space_over_filemarks(drive, MTFSF, 1);
1836                 return 0;
1837         }
1838
1839         return ret ? ret : actually_read;
1840 }
1841
1842 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1843                                      size_t count, loff_t *ppos)
1844 {
1845         struct ide_tape_obj *tape = ide_tape_f(file);
1846         ide_drive_t *drive = tape->drive;
1847         ssize_t actually_written = 0;
1848         ssize_t ret = 0;
1849         u16 ctl = *(u16 *)&tape->caps[12];
1850
1851         /* The drive is write protected. */
1852         if (tape->write_prot)
1853                 return -EACCES;
1854
1855         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1856
1857         /* Initialize write operation */
1858         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1859                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1860                         ide_tape_discard_merge_buffer(drive, 1);
1861                 if (tape->merge_bh || tape->merge_bh_size) {
1862                         printk(KERN_ERR "ide-tape: merge_bh_size "
1863                                 "should be 0 now\n");
1864                         tape->merge_bh_size = 0;
1865                 }
1866                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1867                 if (!tape->merge_bh)
1868                         return -ENOMEM;
1869                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1870                 idetape_init_merge_buffer(tape);
1871
1872                 /*
1873                  * Issue a write 0 command to ensure that DSC handshake is
1874                  * switched from completion mode to buffer available mode. No
1875                  * point in issuing this if DSC overlap isn't supported, some
1876                  * drives (Seagate STT3401A) will return an error.
1877                  */
1878                 if (drive->dsc_overlap) {
1879                         ssize_t retval = idetape_queue_rw_tail(drive,
1880                                                         REQ_IDETAPE_WRITE, 0,
1881                                                         tape->merge_bh);
1882                         if (retval < 0) {
1883                                 ide_tape_kfree_buffer(tape);
1884                                 tape->merge_bh = NULL;
1885                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1886                                 return retval;
1887                         }
1888                 }
1889         }
1890         if (count == 0)
1891                 return (0);
1892         if (tape->merge_bh_size) {
1893                 if (tape->merge_bh_size >= tape->buffer_size) {
1894                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1895                         tape->merge_bh_size = 0;
1896                 }
1897                 actually_written = min((unsigned int)
1898                                 (tape->buffer_size - tape->merge_bh_size),
1899                                 (unsigned int)count);
1900                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1901                                 ret = -EFAULT;
1902                 buf += actually_written;
1903                 tape->merge_bh_size += actually_written;
1904                 count -= actually_written;
1905
1906                 if (tape->merge_bh_size == tape->buffer_size) {
1907                         ssize_t retval;
1908                         tape->merge_bh_size = 0;
1909                         retval = idetape_add_chrdev_write_request(drive, ctl);
1910                         if (retval <= 0)
1911                                 return (retval);
1912                 }
1913         }
1914         while (count >= tape->buffer_size) {
1915                 ssize_t retval;
1916                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1917                         ret = -EFAULT;
1918                 buf += tape->buffer_size;
1919                 count -= tape->buffer_size;
1920                 retval = idetape_add_chrdev_write_request(drive, ctl);
1921                 actually_written += tape->buffer_size;
1922                 if (retval <= 0)
1923                         return (retval);
1924         }
1925         if (count) {
1926                 actually_written += count;
1927                 if (idetape_copy_stage_from_user(tape, buf, count))
1928                         ret = -EFAULT;
1929                 tape->merge_bh_size += count;
1930         }
1931         return ret ? ret : actually_written;
1932 }
1933
1934 static int idetape_write_filemark(ide_drive_t *drive)
1935 {
1936         struct ide_atapi_pc pc;
1937
1938         /* Write a filemark */
1939         idetape_create_write_filemark_cmd(drive, &pc, 1);
1940         if (idetape_queue_pc_tail(drive, &pc)) {
1941                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1942                 return -EIO;
1943         }
1944         return 0;
1945 }
1946
1947 /*
1948  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1949  * requested.
1950  *
1951  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1952  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1953  * usually not supported.
1954  *
1955  * The following commands are currently not supported:
1956  *
1957  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1958  * MT_ST_WRITE_THRESHOLD.
1959  */
1960 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1961 {
1962         idetape_tape_t *tape = drive->driver_data;
1963         struct ide_atapi_pc pc;
1964         int i, retval;
1965
1966         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1967                         mt_op, mt_count);
1968
1969         switch (mt_op) {
1970         case MTFSF:
1971         case MTFSFM:
1972         case MTBSF:
1973         case MTBSFM:
1974                 if (!mt_count)
1975                         return 0;
1976                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1977         default:
1978                 break;
1979         }
1980
1981         switch (mt_op) {
1982         case MTWEOF:
1983                 if (tape->write_prot)
1984                         return -EACCES;
1985                 ide_tape_discard_merge_buffer(drive, 1);
1986                 for (i = 0; i < mt_count; i++) {
1987                         retval = idetape_write_filemark(drive);
1988                         if (retval)
1989                                 return retval;
1990                 }
1991                 return 0;
1992         case MTREW:
1993                 ide_tape_discard_merge_buffer(drive, 0);
1994                 if (idetape_rewind_tape(drive))
1995                         return -EIO;
1996                 return 0;
1997         case MTLOAD:
1998                 ide_tape_discard_merge_buffer(drive, 0);
1999                 idetape_create_load_unload_cmd(drive, &pc,
2000                                                IDETAPE_LU_LOAD_MASK);
2001                 return idetape_queue_pc_tail(drive, &pc);
2002         case MTUNLOAD:
2003         case MTOFFL:
2004                 /*
2005                  * If door is locked, attempt to unlock before
2006                  * attempting to eject.
2007                  */
2008                 if (tape->door_locked) {
2009                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2010                                 if (!idetape_queue_pc_tail(drive, &pc))
2011                                         tape->door_locked = DOOR_UNLOCKED;
2012                 }
2013                 ide_tape_discard_merge_buffer(drive, 0);
2014                 idetape_create_load_unload_cmd(drive, &pc,
2015                                               !IDETAPE_LU_LOAD_MASK);
2016                 retval = idetape_queue_pc_tail(drive, &pc);
2017                 if (!retval)
2018                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
2019                 return retval;
2020         case MTNOP:
2021                 ide_tape_discard_merge_buffer(drive, 0);
2022                 return idetape_flush_tape_buffers(drive);
2023         case MTRETEN:
2024                 ide_tape_discard_merge_buffer(drive, 0);
2025                 idetape_create_load_unload_cmd(drive, &pc,
2026                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2027                 return idetape_queue_pc_tail(drive, &pc);
2028         case MTEOM:
2029                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
2030                 return idetape_queue_pc_tail(drive, &pc);
2031         case MTERASE:
2032                 (void)idetape_rewind_tape(drive);
2033                 idetape_create_erase_cmd(&pc);
2034                 return idetape_queue_pc_tail(drive, &pc);
2035         case MTSETBLK:
2036                 if (mt_count) {
2037                         if (mt_count < tape->blk_size ||
2038                             mt_count % tape->blk_size)
2039                                 return -EIO;
2040                         tape->user_bs_factor = mt_count / tape->blk_size;
2041                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
2042                 } else
2043                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
2044                 return 0;
2045         case MTSEEK:
2046                 ide_tape_discard_merge_buffer(drive, 0);
2047                 return idetape_position_tape(drive,
2048                         mt_count * tape->user_bs_factor, tape->partition, 0);
2049         case MTSETPART:
2050                 ide_tape_discard_merge_buffer(drive, 0);
2051                 return idetape_position_tape(drive, 0, mt_count, 0);
2052         case MTFSR:
2053         case MTBSR:
2054         case MTLOCK:
2055                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
2056                         return 0;
2057                 retval = idetape_queue_pc_tail(drive, &pc);
2058                 if (retval)
2059                         return retval;
2060                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
2061                 return 0;
2062         case MTUNLOCK:
2063                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
2064                         return 0;
2065                 retval = idetape_queue_pc_tail(drive, &pc);
2066                 if (retval)
2067                         return retval;
2068                 tape->door_locked = DOOR_UNLOCKED;
2069                 return 0;
2070         default:
2071                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2072                                 mt_op);
2073                 return -EIO;
2074         }
2075 }
2076
2077 /*
2078  * Our character device ioctls. General mtio.h magnetic io commands are
2079  * supported here, and not in the corresponding block interface. Our own
2080  * ide-tape ioctls are supported on both interfaces.
2081  */
2082 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
2083                                 unsigned int cmd, unsigned long arg)
2084 {
2085         struct ide_tape_obj *tape = ide_tape_f(file);
2086         ide_drive_t *drive = tape->drive;
2087         struct mtop mtop;
2088         struct mtget mtget;
2089         struct mtpos mtpos;
2090         int block_offset = 0, position = tape->first_frame;
2091         void __user *argp = (void __user *)arg;
2092
2093         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
2094
2095         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2096                 ide_tape_flush_merge_buffer(drive);
2097                 idetape_flush_tape_buffers(drive);
2098         }
2099         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
2100                 block_offset = tape->merge_bh_size /
2101                         (tape->blk_size * tape->user_bs_factor);
2102                 position = idetape_read_position(drive);
2103                 if (position < 0)
2104                         return -EIO;
2105         }
2106         switch (cmd) {
2107         case MTIOCTOP:
2108                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
2109                         return -EFAULT;
2110                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
2111         case MTIOCGET:
2112                 memset(&mtget, 0, sizeof(struct mtget));
2113                 mtget.mt_type = MT_ISSCSI2;
2114                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
2115                 mtget.mt_dsreg =
2116                         ((tape->blk_size * tape->user_bs_factor)
2117                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
2118
2119                 if (tape->drv_write_prot)
2120                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
2121
2122                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
2123                         return -EFAULT;
2124                 return 0;
2125         case MTIOCPOS:
2126                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
2127                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
2128                         return -EFAULT;
2129                 return 0;
2130         default:
2131                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2132                         ide_tape_discard_merge_buffer(drive, 1);
2133                 return idetape_blkdev_ioctl(drive, cmd, arg);
2134         }
2135 }
2136
2137 /*
2138  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
2139  * block size with the reported value.
2140  */
2141 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
2142 {
2143         idetape_tape_t *tape = drive->driver_data;
2144         struct ide_atapi_pc pc;
2145
2146         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
2147         if (idetape_queue_pc_tail(drive, &pc)) {
2148                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
2149                 if (tape->blk_size == 0) {
2150                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
2151                                             "block size, assuming 32k\n");
2152                         tape->blk_size = 32768;
2153                 }
2154                 return;
2155         }
2156         tape->blk_size = (pc.buf[4 + 5] << 16) +
2157                                 (pc.buf[4 + 6] << 8)  +
2158                                  pc.buf[4 + 7];
2159         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
2160 }
2161
2162 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
2163 {
2164         unsigned int minor = iminor(inode), i = minor & ~0xc0;
2165         ide_drive_t *drive;
2166         idetape_tape_t *tape;
2167         struct ide_atapi_pc pc;
2168         int retval;
2169
2170         if (i >= MAX_HWIFS * MAX_DRIVES)
2171                 return -ENXIO;
2172
2173         lock_kernel();
2174         tape = ide_tape_chrdev_get(i);
2175         if (!tape) {
2176                 unlock_kernel();
2177                 return -ENXIO;
2178         }
2179
2180         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2181
2182         /*
2183          * We really want to do nonseekable_open(inode, filp); here, but some
2184          * versions of tar incorrectly call lseek on tapes and bail out if that
2185          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
2186          */
2187         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
2188
2189         drive = tape->drive;
2190
2191         filp->private_data = tape;
2192
2193         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
2194                 retval = -EBUSY;
2195                 goto out_put_tape;
2196         }
2197
2198         retval = idetape_wait_ready(drive, 60 * HZ);
2199         if (retval) {
2200                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2201                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
2202                 goto out_put_tape;
2203         }
2204
2205         idetape_read_position(drive);
2206         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
2207                 (void)idetape_rewind_tape(drive);
2208
2209         /* Read block size and write protect status from drive. */
2210         ide_tape_get_bsize_from_bdesc(drive);
2211
2212         /* Set write protect flag if device is opened as read-only. */
2213         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
2214                 tape->write_prot = 1;
2215         else
2216                 tape->write_prot = tape->drv_write_prot;
2217
2218         /* Make sure drive isn't write protected if user wants to write. */
2219         if (tape->write_prot) {
2220                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
2221                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
2222                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2223                         retval = -EROFS;
2224                         goto out_put_tape;
2225                 }
2226         }
2227
2228         /* Lock the tape drive door so user can't eject. */
2229         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2230                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
2231                         if (!idetape_queue_pc_tail(drive, &pc)) {
2232                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2233                                         tape->door_locked = DOOR_LOCKED;
2234                         }
2235                 }
2236         }
2237         unlock_kernel();
2238         return 0;
2239
2240 out_put_tape:
2241         ide_tape_put(tape);
2242         unlock_kernel();
2243         return retval;
2244 }
2245
2246 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2247 {
2248         idetape_tape_t *tape = drive->driver_data;
2249
2250         ide_tape_flush_merge_buffer(drive);
2251         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2252         if (tape->merge_bh != NULL) {
2253                 idetape_pad_zeros(drive, tape->blk_size *
2254                                 (tape->user_bs_factor - 1));
2255                 ide_tape_kfree_buffer(tape);
2256                 tape->merge_bh = NULL;
2257         }
2258         idetape_write_filemark(drive);
2259         idetape_flush_tape_buffers(drive);
2260         idetape_flush_tape_buffers(drive);
2261 }
2262
2263 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2264 {
2265         struct ide_tape_obj *tape = ide_tape_f(filp);
2266         ide_drive_t *drive = tape->drive;
2267         struct ide_atapi_pc pc;
2268         unsigned int minor = iminor(inode);
2269
2270         lock_kernel();
2271         tape = drive->driver_data;
2272
2273         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2274
2275         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2276                 idetape_write_release(drive, minor);
2277         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2278                 if (minor < 128)
2279                         ide_tape_discard_merge_buffer(drive, 1);
2280         }
2281
2282         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2283                 (void) idetape_rewind_tape(drive);
2284         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2285                 if (tape->door_locked == DOOR_LOCKED) {
2286                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
2287                                 if (!idetape_queue_pc_tail(drive, &pc))
2288                                         tape->door_locked = DOOR_UNLOCKED;
2289                         }
2290                 }
2291         }
2292         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2293         ide_tape_put(tape);
2294         unlock_kernel();
2295         return 0;
2296 }
2297
2298 /*
2299  * check the contents of the ATAPI IDENTIFY command results. We return:
2300  *
2301  * 1 - If the tape can be supported by us, based on the information we have so
2302  * far.
2303  *
2304  * 0 - If this tape driver is not currently supported by us.
2305  */
2306 static int idetape_identify_device(ide_drive_t *drive)
2307 {
2308         u8 gcw[2], protocol, device_type, removable, packet_size;
2309
2310         if (drive->id_read == 0)
2311                 return 1;
2312
2313         *((unsigned short *) &gcw) = drive->id->config;
2314
2315         protocol        =   (gcw[1] & 0xC0) >> 6;
2316         device_type     =    gcw[1] & 0x1F;
2317         removable       = !!(gcw[0] & 0x80);
2318         packet_size     =    gcw[0] & 0x3;
2319
2320         /* Check that we can support this device */
2321         if (protocol != 2)
2322                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
2323                                 protocol);
2324         else if (device_type != 1)
2325                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
2326                                 "to tape\n", device_type);
2327         else if (!removable)
2328                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
2329         else if (packet_size != 0) {
2330                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
2331                                 " bytes\n", packet_size);
2332         } else
2333                 return 1;
2334         return 0;
2335 }
2336
2337 static void idetape_get_inquiry_results(ide_drive_t *drive)
2338 {
2339         idetape_tape_t *tape = drive->driver_data;
2340         struct ide_atapi_pc pc;
2341         char fw_rev[6], vendor_id[10], product_id[18];
2342
2343         idetape_create_inquiry_cmd(&pc);
2344         if (idetape_queue_pc_tail(drive, &pc)) {
2345                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2346                                 tape->name);
2347                 return;
2348         }
2349         memcpy(vendor_id, &pc.buf[8], 8);
2350         memcpy(product_id, &pc.buf[16], 16);
2351         memcpy(fw_rev, &pc.buf[32], 4);
2352
2353         ide_fixstring(vendor_id, 10, 0);
2354         ide_fixstring(product_id, 18, 0);
2355         ide_fixstring(fw_rev, 6, 0);
2356
2357         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
2358                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2359 }
2360
2361 /*
2362  * Ask the tape about its various parameters. In particular, we will adjust our
2363  * data transfer buffer size to the recommended value as returned by the tape.
2364  */
2365 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2366 {
2367         idetape_tape_t *tape = drive->driver_data;
2368         struct ide_atapi_pc pc;
2369         u8 *caps;
2370         u8 speed, max_speed;
2371
2372         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2373         if (idetape_queue_pc_tail(drive, &pc)) {
2374                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2375                                 " some default values\n");
2376                 tape->blk_size = 512;
2377                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2378                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2379                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2380                 return;
2381         }
2382         caps = pc.buf + 4 + pc.buf[3];
2383
2384         /* convert to host order and save for later use */
2385         speed = be16_to_cpup((__be16 *)&caps[14]);
2386         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2387
2388         *(u16 *)&caps[8] = max_speed;
2389         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2390         *(u16 *)&caps[14] = speed;
2391         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2392
2393         if (!speed) {
2394                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2395                                 "(assuming 650KB/sec)\n", drive->name);
2396                 *(u16 *)&caps[14] = 650;
2397         }
2398         if (!max_speed) {
2399                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2400                                 "(assuming 650KB/sec)\n", drive->name);
2401                 *(u16 *)&caps[8] = 650;
2402         }
2403
2404         memcpy(&tape->caps, caps, 20);
2405         if (caps[7] & 0x02)
2406                 tape->blk_size = 512;
2407         else if (caps[7] & 0x04)
2408                 tape->blk_size = 1024;
2409 }
2410
2411 #ifdef CONFIG_IDE_PROC_FS
2412 static void idetape_add_settings(ide_drive_t *drive)
2413 {
2414         idetape_tape_t *tape = drive->driver_data;
2415
2416         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2417                         1, 2, (u16 *)&tape->caps[16], NULL);
2418         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2419                         1, 1, (u16 *)&tape->caps[14], NULL);
2420         ide_add_setting(drive, "buffer_size", SETTING_READ, TYPE_INT, 0, 0xffff,
2421                         1, 1024, &tape->buffer_size, NULL);
2422         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
2423                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
2424                         NULL);
2425         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
2426                         1, &drive->dsc_overlap, NULL);
2427         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
2428                         1, 1, &tape->avg_speed, NULL);
2429         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
2430                         1, &tape->debug_mask, NULL);
2431 }
2432 #else
2433 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
2434 #endif
2435
2436 /*
2437  * The function below is called to:
2438  *
2439  * 1. Initialize our various state variables.
2440  * 2. Ask the tape for its capabilities.
2441  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2442  * is chosen based on the recommendation which we received in step 2.
2443  *
2444  * Note that at this point ide.c already assigned us an irq, so that we can
2445  * queue requests here and wait for their completion.
2446  */
2447 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2448 {
2449         unsigned long t;
2450         int speed;
2451         int buffer_size;
2452         u8 gcw[2];
2453         u16 *ctl = (u16 *)&tape->caps[12];
2454
2455         drive->pc_callback = ide_tape_callback;
2456
2457         spin_lock_init(&tape->lock);
2458         drive->dsc_overlap = 1;
2459         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2460                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2461                                  tape->name);
2462                 drive->dsc_overlap = 0;
2463         }
2464         /* Seagate Travan drives do not support DSC overlap. */
2465         if (strstr(drive->id->model, "Seagate STT3401"))
2466                 drive->dsc_overlap = 0;
2467         tape->minor = minor;
2468         tape->name[0] = 'h';
2469         tape->name[1] = 't';
2470         tape->name[2] = '0' + minor;
2471         tape->chrdev_dir = IDETAPE_DIR_NONE;
2472         tape->pc = tape->pc_stack;
2473         *((unsigned short *) &gcw) = drive->id->config;
2474
2475         /* Command packet DRQ type */
2476         if (((gcw[0] & 0x60) >> 5) == 1)
2477                 set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
2478
2479         idetape_get_inquiry_results(drive);
2480         idetape_get_mode_sense_results(drive);
2481         ide_tape_get_bsize_from_bdesc(drive);
2482         tape->user_bs_factor = 1;
2483         tape->buffer_size = *ctl * tape->blk_size;
2484         while (tape->buffer_size > 0xffff) {
2485                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2486                 *ctl /= 2;
2487                 tape->buffer_size = *ctl * tape->blk_size;
2488         }
2489         buffer_size = tape->buffer_size;
2490         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2491         if (buffer_size % PAGE_SIZE) {
2492                 tape->pages_per_buffer++;
2493                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2494         }
2495
2496         /* select the "best" DSC read/write polling freq */
2497         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2498
2499         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2500
2501         /*
2502          * Ensure that the number we got makes sense; limit it within
2503          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2504          */
2505         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2506                                          IDETAPE_DSC_RW_MAX);
2507         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2508                 "%lums tDSC%s\n",
2509                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2510                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2511                 tape->buffer_size / 1024,
2512                 tape->best_dsc_rw_freq * 1000 / HZ,
2513                 drive->using_dma ? ", DMA":"");
2514
2515         idetape_add_settings(drive);
2516 }
2517
2518 static void ide_tape_remove(ide_drive_t *drive)
2519 {
2520         idetape_tape_t *tape = drive->driver_data;
2521
2522         ide_proc_unregister_driver(drive, tape->driver);
2523
2524         ide_unregister_region(tape->disk);
2525
2526         ide_tape_put(tape);
2527 }
2528
2529 static void ide_tape_release(struct kref *kref)
2530 {
2531         struct ide_tape_obj *tape = to_ide_tape(kref);
2532         ide_drive_t *drive = tape->drive;
2533         struct gendisk *g = tape->disk;
2534
2535         BUG_ON(tape->merge_bh_size);
2536
2537         drive->dsc_overlap = 0;
2538         drive->driver_data = NULL;
2539         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2540         device_destroy(idetape_sysfs_class,
2541                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2542         idetape_devs[tape->minor] = NULL;
2543         g->private_data = NULL;
2544         put_disk(g);
2545         kfree(tape);
2546 }
2547
2548 #ifdef CONFIG_IDE_PROC_FS
2549 static int proc_idetape_read_name
2550         (char *page, char **start, off_t off, int count, int *eof, void *data)
2551 {
2552         ide_drive_t     *drive = (ide_drive_t *) data;
2553         idetape_tape_t  *tape = drive->driver_data;
2554         char            *out = page;
2555         int             len;
2556
2557         len = sprintf(out, "%s\n", tape->name);
2558         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2559 }
2560
2561 static ide_proc_entry_t idetape_proc[] = {
2562         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2563         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2564         { NULL, 0, NULL, NULL }
2565 };
2566 #endif
2567
2568 static int ide_tape_probe(ide_drive_t *);
2569
2570 static ide_driver_t idetape_driver = {
2571         .gen_driver = {
2572                 .owner          = THIS_MODULE,
2573                 .name           = "ide-tape",
2574                 .bus            = &ide_bus_type,
2575         },
2576         .probe                  = ide_tape_probe,
2577         .remove                 = ide_tape_remove,
2578         .version                = IDETAPE_VERSION,
2579         .media                  = ide_tape,
2580         .supports_dsc_overlap   = 1,
2581         .do_request             = idetape_do_request,
2582         .end_request            = idetape_end_request,
2583         .error                  = __ide_error,
2584 #ifdef CONFIG_IDE_PROC_FS
2585         .proc                   = idetape_proc,
2586 #endif
2587 };
2588
2589 /* Our character device supporting functions, passed to register_chrdev. */
2590 static const struct file_operations idetape_fops = {
2591         .owner          = THIS_MODULE,
2592         .read           = idetape_chrdev_read,
2593         .write          = idetape_chrdev_write,
2594         .ioctl          = idetape_chrdev_ioctl,
2595         .open           = idetape_chrdev_open,
2596         .release        = idetape_chrdev_release,
2597 };
2598
2599 static int idetape_open(struct inode *inode, struct file *filp)
2600 {
2601         struct gendisk *disk = inode->i_bdev->bd_disk;
2602         struct ide_tape_obj *tape;
2603
2604         tape = ide_tape_get(disk);
2605         if (!tape)
2606                 return -ENXIO;
2607
2608         return 0;
2609 }
2610
2611 static int idetape_release(struct inode *inode, struct file *filp)
2612 {
2613         struct gendisk *disk = inode->i_bdev->bd_disk;
2614         struct ide_tape_obj *tape = ide_tape_g(disk);
2615
2616         ide_tape_put(tape);
2617
2618         return 0;
2619 }
2620
2621 static int idetape_ioctl(struct inode *inode, struct file *file,
2622                         unsigned int cmd, unsigned long arg)
2623 {
2624         struct block_device *bdev = inode->i_bdev;
2625         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2626         ide_drive_t *drive = tape->drive;
2627         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2628         if (err == -EINVAL)
2629                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2630         return err;
2631 }
2632
2633 static struct block_device_operations idetape_block_ops = {
2634         .owner          = THIS_MODULE,
2635         .open           = idetape_open,
2636         .release        = idetape_release,
2637         .ioctl          = idetape_ioctl,
2638 };
2639
2640 static int ide_tape_probe(ide_drive_t *drive)
2641 {
2642         idetape_tape_t *tape;
2643         struct gendisk *g;
2644         int minor;
2645
2646         if (!strstr("ide-tape", drive->driver_req))
2647                 goto failed;
2648         if (!drive->present)
2649                 goto failed;
2650         if (drive->media != ide_tape)
2651                 goto failed;
2652         if (!idetape_identify_device(drive)) {
2653                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2654                                 " the driver\n", drive->name);
2655                 goto failed;
2656         }
2657         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2658         if (tape == NULL) {
2659                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2660                                 drive->name);
2661                 goto failed;
2662         }
2663
2664         g = alloc_disk(1 << PARTN_BITS);
2665         if (!g)
2666                 goto out_free_tape;
2667
2668         ide_init_disk(g, drive);
2669
2670         ide_proc_register_driver(drive, &idetape_driver);
2671
2672         kref_init(&tape->kref);
2673
2674         tape->drive = drive;
2675         tape->driver = &idetape_driver;
2676         tape->disk = g;
2677
2678         g->private_data = &tape->driver;
2679
2680         drive->driver_data = tape;
2681
2682         mutex_lock(&idetape_ref_mutex);
2683         for (minor = 0; idetape_devs[minor]; minor++)
2684                 ;
2685         idetape_devs[minor] = tape;
2686         mutex_unlock(&idetape_ref_mutex);
2687
2688         idetape_setup(drive, tape, minor);
2689
2690         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2691                               MKDEV(IDETAPE_MAJOR, minor), NULL,
2692                               "%s", tape->name);
2693         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2694                               MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2695                               "n%s", tape->name);
2696
2697         g->fops = &idetape_block_ops;
2698         ide_register_region(g);
2699
2700         return 0;
2701
2702 out_free_tape:
2703         kfree(tape);
2704 failed:
2705         return -ENODEV;
2706 }
2707
2708 static void __exit idetape_exit(void)
2709 {
2710         driver_unregister(&idetape_driver.gen_driver);
2711         class_destroy(idetape_sysfs_class);
2712         unregister_chrdev(IDETAPE_MAJOR, "ht");
2713 }
2714
2715 static int __init idetape_init(void)
2716 {
2717         int error = 1;
2718         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2719         if (IS_ERR(idetape_sysfs_class)) {
2720                 idetape_sysfs_class = NULL;
2721                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2722                 error = -EBUSY;
2723                 goto out;
2724         }
2725
2726         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2727                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2728                                 " interface\n");
2729                 error = -EBUSY;
2730                 goto out_free_class;
2731         }
2732
2733         error = driver_register(&idetape_driver.gen_driver);
2734         if (error)
2735                 goto out_free_driver;
2736
2737         return 0;
2738
2739 out_free_driver:
2740         driver_unregister(&idetape_driver.gen_driver);
2741 out_free_class:
2742         class_destroy(idetape_sysfs_class);
2743 out:
2744         return error;
2745 }
2746
2747 MODULE_ALIAS("ide:*m-tape*");
2748 module_init(idetape_init);
2749 module_exit(idetape_exit);
2750 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2751 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2752 MODULE_LICENSE("GPL");