ide: set REQ_PREEMPT request flag in ide_do_drive_cmd() users
[linux-2.6] / drivers / ide / ide-tape.c
1 /*
2  * IDE ATAPI streaming tape driver.
3  *
4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
6  *
7  * This driver was constructed as a student project in the software laboratory
8  * of the faculty of electrical engineering in the Technion - Israel's
9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
10  *
11  * It is hereby placed under the terms of the GNU general public license.
12  * (See linux/COPYING).
13  *
14  * For a historical changelog see
15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
16  */
17
18 #define 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 /* Read/Write error simulation */
148 #define SIMULATE_ERRORS                 0
149
150 /* tape directions */
151 enum {
152         IDETAPE_DIR_NONE  = (1 << 0),
153         IDETAPE_DIR_READ  = (1 << 1),
154         IDETAPE_DIR_WRITE = (1 << 2),
155 };
156
157 struct idetape_bh {
158         u32 b_size;
159         atomic_t b_count;
160         struct idetape_bh *b_reqnext;
161         char *b_data;
162 };
163
164 /* Tape door status */
165 #define DOOR_UNLOCKED                   0
166 #define DOOR_LOCKED                     1
167 #define DOOR_EXPLICITLY_LOCKED          2
168
169 /* Some defines for the SPACE command */
170 #define IDETAPE_SPACE_OVER_FILEMARK     1
171 #define IDETAPE_SPACE_TO_EOD            3
172
173 /* Some defines for the LOAD UNLOAD command */
174 #define IDETAPE_LU_LOAD_MASK            1
175 #define IDETAPE_LU_RETENSION_MASK       2
176 #define IDETAPE_LU_EOT_MASK             4
177
178 /*
179  * Special requests for our block device strategy routine.
180  *
181  * In order to service a character device command, we add special requests to
182  * the tail of our block device request queue and wait for their completion.
183  */
184
185 enum {
186         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
187         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
188         REQ_IDETAPE_READ        = (1 << 2),
189         REQ_IDETAPE_WRITE       = (1 << 3),
190 };
191
192 /* Error codes returned in rq->errors to the higher part of the driver. */
193 #define IDETAPE_ERROR_GENERAL           101
194 #define IDETAPE_ERROR_FILEMARK          102
195 #define IDETAPE_ERROR_EOD               103
196
197 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
198 #define IDETAPE_BLOCK_DESCRIPTOR        0
199 #define IDETAPE_CAPABILITIES_PAGE       0x2a
200
201 /* Tape flag bits values. */
202 enum {
203         IDETAPE_FLAG_IGNORE_DSC         = (1 << 0),
204         /* 0 When the tape position is unknown */
205         IDETAPE_FLAG_ADDRESS_VALID      = (1 << 1),
206         /* Device already opened */
207         IDETAPE_FLAG_BUSY               = (1 << 2),
208         /* Attempt to auto-detect the current user block size */
209         IDETAPE_FLAG_DETECT_BS          = (1 << 3),
210         /* Currently on a filemark */
211         IDETAPE_FLAG_FILEMARK           = (1 << 4),
212         /* DRQ interrupt device */
213         IDETAPE_FLAG_DRQ_INTERRUPT      = (1 << 5),
214         /* 0 = no tape is loaded, so we don't rewind after ejecting */
215         IDETAPE_FLAG_MEDIUM_PRESENT     = (1 << 6),
216 };
217
218 /*
219  * Most of our global data which we need to save even as we leave the driver due
220  * to an interrupt or a timer event is stored in the struct defined below.
221  */
222 typedef struct ide_tape_obj {
223         ide_drive_t     *drive;
224         ide_driver_t    *driver;
225         struct gendisk  *disk;
226         struct kref     kref;
227
228         /*
229          *      Since a typical character device operation requires more
230          *      than one packet command, we provide here enough memory
231          *      for the maximum of interconnected packet commands.
232          *      The packet commands are stored in the circular array pc_stack.
233          *      pc_stack_index points to the last used entry, and warps around
234          *      to the start when we get to the last array entry.
235          *
236          *      pc points to the current processed packet command.
237          *
238          *      failed_pc points to the last failed packet command, or contains
239          *      NULL if we do not need to retry any packet command. This is
240          *      required since an additional packet command is needed before the
241          *      retry, to get detailed information on what went wrong.
242          */
243         /* Current packet command */
244         struct ide_atapi_pc *pc;
245         /* Last failed packet command */
246         struct ide_atapi_pc *failed_pc;
247         /* Packet command stack */
248         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
249         /* Next free packet command storage space */
250         int pc_stack_index;
251         struct request rq_stack[IDETAPE_PC_STACK];
252         /* We implement a circular array */
253         int rq_stack_index;
254
255         /*
256          * DSC polling variables.
257          *
258          * While polling for DSC we use postponed_rq to postpone the current
259          * request so that ide.c will be able to service pending requests on the
260          * other device. Note that at most we will have only one DSC (usually
261          * data transfer) request in the device request queue.
262          */
263         struct request *postponed_rq;
264         /* The time in which we started polling for DSC */
265         unsigned long dsc_polling_start;
266         /* Timer used to poll for dsc */
267         struct timer_list dsc_timer;
268         /* Read/Write dsc polling frequency */
269         unsigned long best_dsc_rw_freq;
270         unsigned long dsc_poll_freq;
271         unsigned long dsc_timeout;
272
273         /* Read position information */
274         u8 partition;
275         /* Current block */
276         unsigned int first_frame;
277
278         /* Last error information */
279         u8 sense_key, asc, ascq;
280
281         /* Character device operation */
282         unsigned int minor;
283         /* device name */
284         char name[4];
285         /* Current character device data transfer direction */
286         u8 chrdev_dir;
287
288         /* tape block size, usually 512 or 1024 bytes */
289         unsigned short blk_size;
290         int user_bs_factor;
291
292         /* Copy of the tape's Capabilities and Mechanical Page */
293         u8 caps[20];
294
295         /*
296          * Active data transfer request parameters.
297          *
298          * At most, there is only one ide-tape originated data transfer request
299          * in the device request queue. This allows ide.c to easily service
300          * requests from the other device when we postpone our active request.
301          */
302
303         /* Data buffer size chosen based on the tape's recommendation */
304         int buffer_size;
305         /* merge buffer */
306         struct idetape_bh *merge_bh;
307         /* size of the merge buffer */
308         int merge_bh_size;
309         /* pointer to current buffer head within the merge buffer */
310         struct idetape_bh *bh;
311         char *b_data;
312         int b_count;
313
314         int pages_per_buffer;
315         /* Wasted space in each stage */
316         int excess_bh_size;
317
318         /* Status/Action flags: long for set_bit */
319         unsigned long flags;
320         /* protects the ide-tape queue */
321         spinlock_t lock;
322
323         /* Measures average tape speed */
324         unsigned long avg_time;
325         int avg_size;
326         int avg_speed;
327
328         /* the door is currently locked */
329         int door_locked;
330         /* the tape hardware is write protected */
331         char drv_write_prot;
332         /* the tape is write protected (hardware or opened as read-only) */
333         char write_prot;
334
335         u32 debug_mask;
336 } idetape_tape_t;
337
338 static DEFINE_MUTEX(idetape_ref_mutex);
339
340 static struct class *idetape_sysfs_class;
341
342 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
343
344 #define ide_tape_g(disk) \
345         container_of((disk)->private_data, struct ide_tape_obj, driver)
346
347 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
348 {
349         struct ide_tape_obj *tape = NULL;
350
351         mutex_lock(&idetape_ref_mutex);
352         tape = ide_tape_g(disk);
353         if (tape)
354                 kref_get(&tape->kref);
355         mutex_unlock(&idetape_ref_mutex);
356         return tape;
357 }
358
359 static void ide_tape_release(struct kref *);
360
361 static void ide_tape_put(struct ide_tape_obj *tape)
362 {
363         mutex_lock(&idetape_ref_mutex);
364         kref_put(&tape->kref, ide_tape_release);
365         mutex_unlock(&idetape_ref_mutex);
366 }
367
368 /*
369  * The variables below are used for the character device interface. Additional
370  * state variables are defined in our ide_drive_t structure.
371  */
372 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
373
374 #define ide_tape_f(file) ((file)->private_data)
375
376 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
377 {
378         struct ide_tape_obj *tape = NULL;
379
380         mutex_lock(&idetape_ref_mutex);
381         tape = idetape_devs[i];
382         if (tape)
383                 kref_get(&tape->kref);
384         mutex_unlock(&idetape_ref_mutex);
385         return tape;
386 }
387
388 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
389                                   unsigned int bcount)
390 {
391         struct idetape_bh *bh = pc->bh;
392         int count;
393
394         while (bcount) {
395                 if (bh == NULL) {
396                         printk(KERN_ERR "ide-tape: bh == NULL in "
397                                 "idetape_input_buffers\n");
398                         ide_pad_transfer(drive, 0, bcount);
399                         return;
400                 }
401                 count = min(
402                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
403                         bcount);
404                 drive->hwif->input_data(drive, NULL, bh->b_data +
405                                         atomic_read(&bh->b_count), count);
406                 bcount -= count;
407                 atomic_add(count, &bh->b_count);
408                 if (atomic_read(&bh->b_count) == bh->b_size) {
409                         bh = bh->b_reqnext;
410                         if (bh)
411                                 atomic_set(&bh->b_count, 0);
412                 }
413         }
414         pc->bh = bh;
415 }
416
417 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
418                                    unsigned int bcount)
419 {
420         struct idetape_bh *bh = pc->bh;
421         int count;
422
423         while (bcount) {
424                 if (bh == NULL) {
425                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
426                                         __func__);
427                         return;
428                 }
429                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
430                 drive->hwif->output_data(drive, NULL, pc->b_data, count);
431                 bcount -= count;
432                 pc->b_data += count;
433                 pc->b_count -= count;
434                 if (!pc->b_count) {
435                         bh = bh->b_reqnext;
436                         pc->bh = bh;
437                         if (bh) {
438                                 pc->b_data = bh->b_data;
439                                 pc->b_count = atomic_read(&bh->b_count);
440                         }
441                 }
442         }
443 }
444
445 static void idetape_update_buffers(struct ide_atapi_pc *pc)
446 {
447         struct idetape_bh *bh = pc->bh;
448         int count;
449         unsigned int bcount = pc->xferred;
450
451         if (pc->flags & PC_FLAG_WRITING)
452                 return;
453         while (bcount) {
454                 if (bh == NULL) {
455                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
456                                         __func__);
457                         return;
458                 }
459                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
460                 atomic_set(&bh->b_count, count);
461                 if (atomic_read(&bh->b_count) == bh->b_size)
462                         bh = bh->b_reqnext;
463                 bcount -= count;
464         }
465         pc->bh = bh;
466 }
467
468 /*
469  *      idetape_next_pc_storage returns a pointer to a place in which we can
470  *      safely store a packet command, even though we intend to leave the
471  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
472  *      commands is allocated at initialization time.
473  */
474 static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
475 {
476         idetape_tape_t *tape = drive->driver_data;
477
478         debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
479
480         if (tape->pc_stack_index == IDETAPE_PC_STACK)
481                 tape->pc_stack_index = 0;
482         return (&tape->pc_stack[tape->pc_stack_index++]);
483 }
484
485 /*
486  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
487  *      Since we queue packet commands in the request queue, we need to
488  *      allocate a request, along with the allocation of a packet command.
489  */
490
491 /**************************************************************
492  *                                                            *
493  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
494  *  followed later on by kfree().   -ml                       *
495  *                                                            *
496  **************************************************************/
497
498 static struct request *idetape_next_rq_storage(ide_drive_t *drive)
499 {
500         idetape_tape_t *tape = drive->driver_data;
501
502         debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
503
504         if (tape->rq_stack_index == IDETAPE_PC_STACK)
505                 tape->rq_stack_index = 0;
506         return (&tape->rq_stack[tape->rq_stack_index++]);
507 }
508
509 static void idetape_init_pc(struct ide_atapi_pc *pc)
510 {
511         memset(pc->c, 0, 12);
512         pc->retries = 0;
513         pc->flags = 0;
514         pc->req_xfer = 0;
515         pc->buf = pc->pc_buf;
516         pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
517         pc->bh = NULL;
518         pc->b_data = NULL;
519 }
520
521 /*
522  * called on each failed packet command retry to analyze the request sense. We
523  * currently do not utilize this information.
524  */
525 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
526 {
527         idetape_tape_t *tape = drive->driver_data;
528         struct ide_atapi_pc *pc = tape->failed_pc;
529
530         tape->sense_key = sense[2] & 0xF;
531         tape->asc       = sense[12];
532         tape->ascq      = sense[13];
533
534         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
535                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
536
537         /* Correct pc->xferred by asking the tape.       */
538         if (pc->flags & PC_FLAG_DMA_ERROR) {
539                 pc->xferred = pc->req_xfer -
540                         tape->blk_size *
541                         get_unaligned_be32(&sense[3]);
542                 idetape_update_buffers(pc);
543         }
544
545         /*
546          * If error was the result of a zero-length read or write command,
547          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
548          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
549          */
550         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
551             /* length == 0 */
552             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
553                 if (tape->sense_key == 5) {
554                         /* don't report an error, everything's ok */
555                         pc->error = 0;
556                         /* don't retry read/write */
557                         pc->flags |= PC_FLAG_ABORT;
558                 }
559         }
560         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
561                 pc->error = IDETAPE_ERROR_FILEMARK;
562                 pc->flags |= PC_FLAG_ABORT;
563         }
564         if (pc->c[0] == WRITE_6) {
565                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
566                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
567                         pc->error = IDETAPE_ERROR_EOD;
568                         pc->flags |= PC_FLAG_ABORT;
569                 }
570         }
571         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
572                 if (tape->sense_key == 8) {
573                         pc->error = IDETAPE_ERROR_EOD;
574                         pc->flags |= PC_FLAG_ABORT;
575                 }
576                 if (!(pc->flags & PC_FLAG_ABORT) &&
577                     pc->xferred)
578                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
579         }
580 }
581
582 /* Free data buffers completely. */
583 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
584 {
585         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
586
587         while (bh) {
588                 u32 size = bh->b_size;
589
590                 while (size) {
591                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
592
593                         if (bh->b_data)
594                                 free_pages((unsigned long)bh->b_data, order);
595
596                         size &= (order-1);
597                         bh->b_data += (1 << order) * PAGE_SIZE;
598                 }
599                 prev_bh = bh;
600                 bh = bh->b_reqnext;
601                 kfree(prev_bh);
602         }
603         kfree(tape->merge_bh);
604 }
605
606 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
607 {
608         struct request *rq = HWGROUP(drive)->rq;
609         idetape_tape_t *tape = drive->driver_data;
610         unsigned long flags;
611         int error;
612
613         debug_log(DBG_PROCS, "Enter %s\n", __func__);
614
615         switch (uptodate) {
616         case 0: error = IDETAPE_ERROR_GENERAL; break;
617         case 1: error = 0; break;
618         default: error = uptodate;
619         }
620         rq->errors = error;
621         if (error)
622                 tape->failed_pc = NULL;
623
624         if (!blk_special_request(rq)) {
625                 ide_end_request(drive, uptodate, nr_sects);
626                 return 0;
627         }
628
629         spin_lock_irqsave(&tape->lock, flags);
630
631         ide_end_drive_cmd(drive, 0, 0);
632
633         spin_unlock_irqrestore(&tape->lock, flags);
634         return 0;
635 }
636
637 static ide_startstop_t idetape_request_sense_callback(ide_drive_t *drive)
638 {
639         idetape_tape_t *tape = drive->driver_data;
640
641         debug_log(DBG_PROCS, "Enter %s\n", __func__);
642
643         if (!tape->pc->error) {
644                 idetape_analyze_error(drive, tape->pc->buf);
645                 idetape_end_request(drive, 1, 0);
646         } else {
647                 printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - "
648                                 "Aborting request!\n");
649                 idetape_end_request(drive, 0, 0);
650         }
651         return ide_stopped;
652 }
653
654 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
655 {
656         idetape_init_pc(pc);
657         pc->c[0] = REQUEST_SENSE;
658         pc->c[4] = 20;
659         pc->req_xfer = 20;
660         pc->idetape_callback = &idetape_request_sense_callback;
661 }
662
663 static void idetape_init_rq(struct request *rq, u8 cmd)
664 {
665         blk_rq_init(NULL, rq);
666         rq->cmd_type = REQ_TYPE_SPECIAL;
667         rq->cmd[0] = cmd;
668 }
669
670 /*
671  * Generate a new packet command request in front of the request queue, before
672  * the current request, so that it will be processed immediately, on the next
673  * pass through the driver. The function below is called from the request
674  * handling part of the driver (the "bottom" part). Safe storage for the request
675  * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
676  *
677  * Memory for those requests is pre-allocated at initialization time, and is
678  * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
679  * the maximum possible number of inter-dependent packet commands.
680  *
681  * The higher level of the driver - The ioctl handler and the character device
682  * handling functions should queue request to the lower level part and wait for
683  * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
684  */
685 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
686                                   struct request *rq)
687 {
688         struct ide_tape_obj *tape = drive->driver_data;
689
690         idetape_init_rq(rq, REQ_IDETAPE_PC1);
691         rq->cmd_flags |= REQ_PREEMPT;
692         rq->buffer = (char *) pc;
693         rq->rq_disk = tape->disk;
694         (void) ide_do_drive_cmd(drive, rq, ide_preempt);
695 }
696
697 /*
698  *      idetape_retry_pc is called when an error was detected during the
699  *      last packet command. We queue a request sense packet command in
700  *      the head of the request list.
701  */
702 static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
703 {
704         idetape_tape_t *tape = drive->driver_data;
705         struct ide_atapi_pc *pc;
706         struct request *rq;
707
708         (void)ide_read_error(drive);
709         pc = idetape_next_pc_storage(drive);
710         rq = idetape_next_rq_storage(drive);
711         idetape_create_request_sense_cmd(pc);
712         set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
713         idetape_queue_pc_head(drive, pc, rq);
714         return ide_stopped;
715 }
716
717 /*
718  * Postpone the current request so that ide.c will be able to service requests
719  * from another device on the same hwgroup while we are polling for DSC.
720  */
721 static void idetape_postpone_request(ide_drive_t *drive)
722 {
723         idetape_tape_t *tape = drive->driver_data;
724
725         debug_log(DBG_PROCS, "Enter %s\n", __func__);
726
727         tape->postponed_rq = HWGROUP(drive)->rq;
728         ide_stall_queue(drive, tape->dsc_poll_freq);
729 }
730
731 typedef void idetape_io_buf(ide_drive_t *, struct ide_atapi_pc *, unsigned int);
732
733 /*
734  * This is the usual interrupt handler which will be called during a packet
735  * command. We will transfer some of the data (as requested by the drive) and
736  * will re-point interrupt handler to us. When data transfer is finished, we
737  * will act according to the algorithm described before
738  * idetape_issue_pc.
739  */
740 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
741 {
742         ide_hwif_t *hwif = drive->hwif;
743         idetape_tape_t *tape = drive->driver_data;
744         struct ide_atapi_pc *pc = tape->pc;
745         xfer_func_t *xferfunc;
746         idetape_io_buf *iobuf;
747         unsigned int temp;
748 #if SIMULATE_ERRORS
749         static int error_sim_count;
750 #endif
751         u16 bcount;
752         u8 stat, ireason;
753
754         debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
755
756         /* Clear the interrupt */
757         stat = ide_read_status(drive);
758
759         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
760                 if (hwif->dma_ops->dma_end(drive) || (stat & ERR_STAT)) {
761                         /*
762                          * A DMA error is sometimes expected. For example,
763                          * if the tape is crossing a filemark during a
764                          * READ command, it will issue an irq and position
765                          * itself before the filemark, so that only a partial
766                          * data transfer will occur (which causes the DMA
767                          * error). In that case, we will later ask the tape
768                          * how much bytes of the original request were
769                          * actually transferred (we can't receive that
770                          * information from the DMA engine on most chipsets).
771                          */
772
773                         /*
774                          * On the contrary, a DMA error is never expected;
775                          * it usually indicates a hardware error or abort.
776                          * If the tape crosses a filemark during a READ
777                          * command, it will issue an irq and position itself
778                          * after the filemark (not before). Only a partial
779                          * data transfer will occur, but no DMA error.
780                          * (AS, 19 Apr 2001)
781                          */
782                         pc->flags |= PC_FLAG_DMA_ERROR;
783                 } else {
784                         pc->xferred = pc->req_xfer;
785                         idetape_update_buffers(pc);
786                 }
787                 debug_log(DBG_PROCS, "DMA finished\n");
788
789         }
790
791         /* No more interrupts */
792         if ((stat & DRQ_STAT) == 0) {
793                 debug_log(DBG_SENSE, "Packet command completed, %d bytes"
794                                 " transferred\n", pc->xferred);
795
796                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
797                 local_irq_enable();
798
799 #if SIMULATE_ERRORS
800                 if ((pc->c[0] == WRITE_6 || pc->c[0] == READ_6) &&
801                     (++error_sim_count % 100) == 0) {
802                         printk(KERN_INFO "ide-tape: %s: simulating error\n",
803                                 tape->name);
804                         stat |= ERR_STAT;
805                 }
806 #endif
807                 if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
808                         stat &= ~ERR_STAT;
809                 if ((stat & ERR_STAT) || (pc->flags & PC_FLAG_DMA_ERROR)) {
810                         /* Error detected */
811                         debug_log(DBG_ERR, "%s: I/O error\n", tape->name);
812
813                         if (pc->c[0] == REQUEST_SENSE) {
814                                 printk(KERN_ERR "ide-tape: I/O error in request"
815                                                 " sense command\n");
816                                 return ide_do_reset(drive);
817                         }
818                         debug_log(DBG_ERR, "[cmd %x]: check condition\n",
819                                         pc->c[0]);
820
821                         /* Retry operation */
822                         return idetape_retry_pc(drive);
823                 }
824                 pc->error = 0;
825                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
826                     (stat & SEEK_STAT) == 0) {
827                         /* Media access command */
828                         tape->dsc_polling_start = jiffies;
829                         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
830                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
831                         /* Allow ide.c to handle other requests */
832                         idetape_postpone_request(drive);
833                         return ide_stopped;
834                 }
835                 if (tape->failed_pc == pc)
836                         tape->failed_pc = NULL;
837                 /* Command finished - Call the callback function */
838                 return pc->idetape_callback(drive);
839         }
840
841         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
842                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
843                 printk(KERN_ERR "ide-tape: The tape wants to issue more "
844                                 "interrupts in DMA mode\n");
845                 printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
846                 ide_dma_off(drive);
847                 return ide_do_reset(drive);
848         }
849         /* Get the number of bytes to transfer on this interrupt. */
850         bcount = (hwif->INB(hwif->io_ports.lbah_addr) << 8) |
851                   hwif->INB(hwif->io_ports.lbam_addr);
852
853         ireason = hwif->INB(hwif->io_ports.nsect_addr);
854
855         if (ireason & CD) {
856                 printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
857                 return ide_do_reset(drive);
858         }
859         if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
860                 /* Hopefully, we will never get here */
861                 printk(KERN_ERR "ide-tape: We wanted to %s, ",
862                                 (ireason & IO) ? "Write" : "Read");
863                 printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
864                                 (ireason & IO) ? "Read" : "Write");
865                 return ide_do_reset(drive);
866         }
867         if (!(pc->flags & PC_FLAG_WRITING)) {
868                 /* Reading - Check that we have enough space */
869                 temp = pc->xferred + bcount;
870                 if (temp > pc->req_xfer) {
871                         if (temp > pc->buf_size) {
872                                 printk(KERN_ERR "ide-tape: The tape wants to "
873                                         "send us more data than expected "
874                                         "- discarding data\n");
875                                 ide_pad_transfer(drive, 0, bcount);
876                                 ide_set_handler(drive, &idetape_pc_intr,
877                                                 IDETAPE_WAIT_CMD, NULL);
878                                 return ide_started;
879                         }
880                         debug_log(DBG_SENSE, "The tape wants to send us more "
881                                 "data than expected - allowing transfer\n");
882                 }
883                 iobuf = &idetape_input_buffers;
884                 xferfunc = hwif->input_data;
885         } else {
886                 iobuf = &idetape_output_buffers;
887                 xferfunc = hwif->output_data;
888         }
889
890         if (pc->bh)
891                 iobuf(drive, pc, bcount);
892         else
893                 xferfunc(drive, NULL, pc->cur_pos, bcount);
894
895         /* Update the current position */
896         pc->xferred += bcount;
897         pc->cur_pos += bcount;
898
899         debug_log(DBG_SENSE, "[cmd %x] transferred %d bytes on that intr.\n",
900                         pc->c[0], bcount);
901
902         /* And set the interrupt handler again */
903         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
904         return ide_started;
905 }
906
907 /*
908  * Packet Command Interface
909  *
910  * The current Packet Command is available in tape->pc, and will not change
911  * until we finish handling it. Each packet command is associated with a
912  * callback function that will be called when the command is finished.
913  *
914  * The handling will be done in three stages:
915  *
916  * 1. idetape_issue_pc will send the packet command to the drive, and will set
917  * the interrupt handler to idetape_pc_intr.
918  *
919  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
920  * repeated until the device signals us that no more interrupts will be issued.
921  *
922  * 3. ATAPI Tape media access commands have immediate status with a delayed
923  * process. In case of a successful initiation of a media access packet command,
924  * the DSC bit will be set when the actual execution of the command is finished.
925  * Since the tape drive will not issue an interrupt, we have to poll for this
926  * event. In this case, we define the request as "low priority request" by
927  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
928  * exit the driver.
929  *
930  * ide.c will then give higher priority to requests which originate from the
931  * other device, until will change rq_status to RQ_ACTIVE.
932  *
933  * 4. When the packet command is finished, it will be checked for errors.
934  *
935  * 5. In case an error was found, we queue a request sense packet command in
936  * front of the request queue and retry the operation up to
937  * IDETAPE_MAX_PC_RETRIES times.
938  *
939  * 6. In case no error was found, or we decided to give up and not to retry
940  * again, the callback function will be called and then we will handle the next
941  * request.
942  */
943 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
944 {
945         ide_hwif_t *hwif = drive->hwif;
946         idetape_tape_t *tape = drive->driver_data;
947         struct ide_atapi_pc *pc = tape->pc;
948         int retries = 100;
949         ide_startstop_t startstop;
950         u8 ireason;
951
952         if (ide_wait_stat(&startstop, drive, DRQ_STAT, BUSY_STAT, WAIT_READY)) {
953                 printk(KERN_ERR "ide-tape: Strange, packet command initiated "
954                                 "yet DRQ isn't asserted\n");
955                 return startstop;
956         }
957         ireason = hwif->INB(hwif->io_ports.nsect_addr);
958         while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
959                 printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
960                                 "a packet command, retrying\n");
961                 udelay(100);
962                 ireason = hwif->INB(hwif->io_ports.nsect_addr);
963                 if (retries == 0) {
964                         printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
965                                         "issuing a packet command, ignoring\n");
966                         ireason |= CD;
967                         ireason &= ~IO;
968                 }
969         }
970         if ((ireason & CD) == 0 || (ireason & IO)) {
971                 printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
972                                 "a packet command\n");
973                 return ide_do_reset(drive);
974         }
975         /* Set the interrupt routine */
976         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
977 #ifdef CONFIG_BLK_DEV_IDEDMA
978         /* Begin DMA, if necessary */
979         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS)
980                 hwif->dma_ops->dma_start(drive);
981 #endif
982         /* Send the actual packet */
983         hwif->output_data(drive, NULL, pc->c, 12);
984
985         return ide_started;
986 }
987
988 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
989                 struct ide_atapi_pc *pc)
990 {
991         ide_hwif_t *hwif = drive->hwif;
992         idetape_tape_t *tape = drive->driver_data;
993         int dma_ok = 0;
994         u16 bcount;
995
996         if (tape->pc->c[0] == REQUEST_SENSE &&
997             pc->c[0] == REQUEST_SENSE) {
998                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
999                         "Two request sense in serial were issued\n");
1000         }
1001
1002         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
1003                 tape->failed_pc = pc;
1004         /* Set the current packet command */
1005         tape->pc = pc;
1006
1007         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
1008                 (pc->flags & PC_FLAG_ABORT)) {
1009                 /*
1010                  * We will "abort" retrying a packet command in case legitimate
1011                  * error code was received (crossing a filemark, or end of the
1012                  * media, for example).
1013                  */
1014                 if (!(pc->flags & PC_FLAG_ABORT)) {
1015                         if (!(pc->c[0] == TEST_UNIT_READY &&
1016                               tape->sense_key == 2 && tape->asc == 4 &&
1017                              (tape->ascq == 1 || tape->ascq == 8))) {
1018                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
1019                                                 "pc = %2x, key = %2x, "
1020                                                 "asc = %2x, ascq = %2x\n",
1021                                                 tape->name, pc->c[0],
1022                                                 tape->sense_key, tape->asc,
1023                                                 tape->ascq);
1024                         }
1025                         /* Giving up */
1026                         pc->error = IDETAPE_ERROR_GENERAL;
1027                 }
1028                 tape->failed_pc = NULL;
1029                 return pc->idetape_callback(drive);
1030         }
1031         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
1032
1033         pc->retries++;
1034         /* We haven't transferred any data yet */
1035         pc->xferred = 0;
1036         pc->cur_pos = pc->buf;
1037         /* Request to transfer the entire buffer at once */
1038         bcount = pc->req_xfer;
1039
1040         if (pc->flags & PC_FLAG_DMA_ERROR) {
1041                 pc->flags &= ~PC_FLAG_DMA_ERROR;
1042                 printk(KERN_WARNING "ide-tape: DMA disabled, "
1043                                 "reverting to PIO\n");
1044                 ide_dma_off(drive);
1045         }
1046         if ((pc->flags & PC_FLAG_DMA_RECOMMENDED) && drive->using_dma)
1047                 dma_ok = !hwif->dma_ops->dma_setup(drive);
1048
1049         ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK |
1050                            IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
1051
1052         if (dma_ok)
1053                 /* Will begin DMA later */
1054                 pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
1055         if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags)) {
1056                 ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
1057                                     IDETAPE_WAIT_CMD, NULL);
1058                 return ide_started;
1059         } else {
1060                 ide_execute_pkt_cmd(drive);
1061                 return idetape_transfer_pc(drive);
1062         }
1063 }
1064
1065 static ide_startstop_t idetape_pc_callback(ide_drive_t *drive)
1066 {
1067         idetape_tape_t *tape = drive->driver_data;
1068
1069         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1070
1071         idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
1072         return ide_stopped;
1073 }
1074
1075 /* A mode sense command is used to "sense" tape parameters. */
1076 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
1077 {
1078         idetape_init_pc(pc);
1079         pc->c[0] = MODE_SENSE;
1080         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1081                 /* DBD = 1 - Don't return block descriptors */
1082                 pc->c[1] = 8;
1083         pc->c[2] = page_code;
1084         /*
1085          * Changed pc->c[3] to 0 (255 will at best return unused info).
1086          *
1087          * For SCSI this byte is defined as subpage instead of high byte
1088          * of length and some IDE drives seem to interpret it this way
1089          * and return an error when 255 is used.
1090          */
1091         pc->c[3] = 0;
1092         /* We will just discard data in that case */
1093         pc->c[4] = 255;
1094         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1095                 pc->req_xfer = 12;
1096         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
1097                 pc->req_xfer = 24;
1098         else
1099                 pc->req_xfer = 50;
1100         pc->idetape_callback = &idetape_pc_callback;
1101 }
1102
1103 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
1104 {
1105         idetape_tape_t *tape = drive->driver_data;
1106         struct ide_atapi_pc *pc = tape->pc;
1107         u8 stat;
1108
1109         stat = ide_read_status(drive);
1110
1111         if (stat & SEEK_STAT) {
1112                 if (stat & ERR_STAT) {
1113                         /* Error detected */
1114                         if (pc->c[0] != TEST_UNIT_READY)
1115                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
1116                                                 tape->name);
1117                         /* Retry operation */
1118                         return idetape_retry_pc(drive);
1119                 }
1120                 pc->error = 0;
1121                 if (tape->failed_pc == pc)
1122                         tape->failed_pc = NULL;
1123         } else {
1124                 pc->error = IDETAPE_ERROR_GENERAL;
1125                 tape->failed_pc = NULL;
1126         }
1127         return pc->idetape_callback(drive);
1128 }
1129
1130 static ide_startstop_t idetape_rw_callback(ide_drive_t *drive)
1131 {
1132         idetape_tape_t *tape = drive->driver_data;
1133         struct request *rq = HWGROUP(drive)->rq;
1134         int blocks = tape->pc->xferred / tape->blk_size;
1135
1136         tape->avg_size += blocks * tape->blk_size;
1137
1138         if (time_after_eq(jiffies, tape->avg_time + HZ)) {
1139                 tape->avg_speed = tape->avg_size * HZ /
1140                                 (jiffies - tape->avg_time) / 1024;
1141                 tape->avg_size = 0;
1142                 tape->avg_time = jiffies;
1143         }
1144         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1145
1146         tape->first_frame += blocks;
1147         rq->current_nr_sectors -= blocks;
1148
1149         if (!tape->pc->error)
1150                 idetape_end_request(drive, 1, 0);
1151         else
1152                 idetape_end_request(drive, tape->pc->error, 0);
1153         return ide_stopped;
1154 }
1155
1156 static void idetape_create_read_cmd(idetape_tape_t *tape,
1157                 struct ide_atapi_pc *pc,
1158                 unsigned int length, struct idetape_bh *bh)
1159 {
1160         idetape_init_pc(pc);
1161         pc->c[0] = READ_6;
1162         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1163         pc->c[1] = 1;
1164         pc->idetape_callback = &idetape_rw_callback;
1165         pc->bh = bh;
1166         atomic_set(&bh->b_count, 0);
1167         pc->buf = NULL;
1168         pc->buf_size = length * tape->blk_size;
1169         pc->req_xfer = pc->buf_size;
1170         if (pc->req_xfer == tape->buffer_size)
1171                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1172 }
1173
1174 static void idetape_create_write_cmd(idetape_tape_t *tape,
1175                 struct ide_atapi_pc *pc,
1176                 unsigned int length, struct idetape_bh *bh)
1177 {
1178         idetape_init_pc(pc);
1179         pc->c[0] = WRITE_6;
1180         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1181         pc->c[1] = 1;
1182         pc->idetape_callback = &idetape_rw_callback;
1183         pc->flags |= PC_FLAG_WRITING;
1184         pc->bh = bh;
1185         pc->b_data = bh->b_data;
1186         pc->b_count = atomic_read(&bh->b_count);
1187         pc->buf = NULL;
1188         pc->buf_size = length * tape->blk_size;
1189         pc->req_xfer = pc->buf_size;
1190         if (pc->req_xfer == tape->buffer_size)
1191                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1192 }
1193
1194 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1195                                           struct request *rq, sector_t block)
1196 {
1197         idetape_tape_t *tape = drive->driver_data;
1198         struct ide_atapi_pc *pc = NULL;
1199         struct request *postponed_rq = tape->postponed_rq;
1200         u8 stat;
1201
1202         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
1203                         " current_nr_sectors: %d\n",
1204                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1205
1206         if (!blk_special_request(rq)) {
1207                 /* We do not support buffer cache originated requests. */
1208                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1209                         "request queue (%d)\n", drive->name, rq->cmd_type);
1210                 ide_end_request(drive, 0, 0);
1211                 return ide_stopped;
1212         }
1213
1214         /* Retry a failed packet command */
1215         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE)
1216                 return idetape_issue_pc(drive, tape->failed_pc);
1217
1218         if (postponed_rq != NULL)
1219                 if (rq != postponed_rq) {
1220                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1221                                         "Two DSC requests were queued\n");
1222                         idetape_end_request(drive, 0, 0);
1223                         return ide_stopped;
1224                 }
1225
1226         tape->postponed_rq = NULL;
1227
1228         /*
1229          * If the tape is still busy, postpone our request and service
1230          * the other device meanwhile.
1231          */
1232         stat = ide_read_status(drive);
1233
1234         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
1235                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1236
1237         if (drive->post_reset == 1) {
1238                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1239                 drive->post_reset = 0;
1240         }
1241
1242         if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&
1243             (stat & SEEK_STAT) == 0) {
1244                 if (postponed_rq == NULL) {
1245                         tape->dsc_polling_start = jiffies;
1246                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1247                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1248                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1249                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1250                                 tape->name);
1251                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1252                                 idetape_media_access_finished(drive);
1253                                 return ide_stopped;
1254                         } else {
1255                                 return ide_do_reset(drive);
1256                         }
1257                 } else if (time_after(jiffies,
1258                                         tape->dsc_polling_start +
1259                                         IDETAPE_DSC_MA_THRESHOLD))
1260                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1261                 idetape_postpone_request(drive);
1262                 return ide_stopped;
1263         }
1264         if (rq->cmd[0] & REQ_IDETAPE_READ) {
1265                 pc = idetape_next_pc_storage(drive);
1266                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
1267                                         (struct idetape_bh *)rq->special);
1268                 goto out;
1269         }
1270         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1271                 pc = idetape_next_pc_storage(drive);
1272                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
1273                                          (struct idetape_bh *)rq->special);
1274                 goto out;
1275         }
1276         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
1277                 pc = (struct ide_atapi_pc *) rq->buffer;
1278                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
1279                 rq->cmd[0] |= REQ_IDETAPE_PC2;
1280                 goto out;
1281         }
1282         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1283                 idetape_media_access_finished(drive);
1284                 return ide_stopped;
1285         }
1286         BUG();
1287 out:
1288         return idetape_issue_pc(drive, pc);
1289 }
1290
1291 /*
1292  * The function below uses __get_free_pages to allocate a data buffer of size
1293  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
1294  * much as possible.
1295  *
1296  * It returns a pointer to the newly allocated buffer, or NULL in case of
1297  * failure.
1298  */
1299 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
1300                                                   int full, int clear)
1301 {
1302         struct idetape_bh *prev_bh, *bh, *merge_bh;
1303         int pages = tape->pages_per_buffer;
1304         unsigned int order, b_allocd;
1305         char *b_data = NULL;
1306
1307         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1308         bh = merge_bh;
1309         if (bh == NULL)
1310                 goto abort;
1311
1312         order = fls(pages) - 1;
1313         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1314         if (!bh->b_data)
1315                 goto abort;
1316         b_allocd = (1 << order) * PAGE_SIZE;
1317         pages &= (order-1);
1318
1319         if (clear)
1320                 memset(bh->b_data, 0, b_allocd);
1321         bh->b_reqnext = NULL;
1322         bh->b_size = b_allocd;
1323         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1324
1325         while (pages) {
1326                 order = fls(pages) - 1;
1327                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1328                 if (!b_data)
1329                         goto abort;
1330                 b_allocd = (1 << order) * PAGE_SIZE;
1331
1332                 if (clear)
1333                         memset(b_data, 0, b_allocd);
1334
1335                 /* newly allocated page frames below buffer header or ...*/
1336                 if (bh->b_data == b_data + b_allocd) {
1337                         bh->b_size += b_allocd;
1338                         bh->b_data -= b_allocd;
1339                         if (full)
1340                                 atomic_add(b_allocd, &bh->b_count);
1341                         continue;
1342                 }
1343                 /* they are above the header */
1344                 if (b_data == bh->b_data + bh->b_size) {
1345                         bh->b_size += b_allocd;
1346                         if (full)
1347                                 atomic_add(b_allocd, &bh->b_count);
1348                         continue;
1349                 }
1350                 prev_bh = bh;
1351                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1352                 if (!bh) {
1353                         free_pages((unsigned long) b_data, order);
1354                         goto abort;
1355                 }
1356                 bh->b_reqnext = NULL;
1357                 bh->b_data = b_data;
1358                 bh->b_size = b_allocd;
1359                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1360                 prev_bh->b_reqnext = bh;
1361
1362                 pages &= (order-1);
1363         }
1364
1365         bh->b_size -= tape->excess_bh_size;
1366         if (full)
1367                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1368         return merge_bh;
1369 abort:
1370         ide_tape_kfree_buffer(tape);
1371         return NULL;
1372 }
1373
1374 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1375                                         const char __user *buf, int n)
1376 {
1377         struct idetape_bh *bh = tape->bh;
1378         int count;
1379         int ret = 0;
1380
1381         while (n) {
1382                 if (bh == NULL) {
1383                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1384                                         __func__);
1385                         return 1;
1386                 }
1387                 count = min((unsigned int)
1388                                 (bh->b_size - atomic_read(&bh->b_count)),
1389                                 (unsigned int)n);
1390                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1391                                 count))
1392                         ret = 1;
1393                 n -= count;
1394                 atomic_add(count, &bh->b_count);
1395                 buf += count;
1396                 if (atomic_read(&bh->b_count) == bh->b_size) {
1397                         bh = bh->b_reqnext;
1398                         if (bh)
1399                                 atomic_set(&bh->b_count, 0);
1400                 }
1401         }
1402         tape->bh = bh;
1403         return ret;
1404 }
1405
1406 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1407                                       int n)
1408 {
1409         struct idetape_bh *bh = tape->bh;
1410         int count;
1411         int ret = 0;
1412
1413         while (n) {
1414                 if (bh == NULL) {
1415                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1416                                         __func__);
1417                         return 1;
1418                 }
1419                 count = min(tape->b_count, n);
1420                 if  (copy_to_user(buf, tape->b_data, count))
1421                         ret = 1;
1422                 n -= count;
1423                 tape->b_data += count;
1424                 tape->b_count -= count;
1425                 buf += count;
1426                 if (!tape->b_count) {
1427                         bh = bh->b_reqnext;
1428                         tape->bh = bh;
1429                         if (bh) {
1430                                 tape->b_data = bh->b_data;
1431                                 tape->b_count = atomic_read(&bh->b_count);
1432                         }
1433                 }
1434         }
1435         return ret;
1436 }
1437
1438 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1439 {
1440         struct idetape_bh *bh = tape->merge_bh;
1441         tape->bh = tape->merge_bh;
1442
1443         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1444                 atomic_set(&bh->b_count, 0);
1445         else {
1446                 tape->b_data = bh->b_data;
1447                 tape->b_count = atomic_read(&bh->b_count);
1448         }
1449 }
1450
1451 static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
1452 {
1453         idetape_tape_t *tape = drive->driver_data;
1454         u8 *readpos = tape->pc->buf;
1455
1456         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1457
1458         if (!tape->pc->error) {
1459                 debug_log(DBG_SENSE, "BOP - %s\n",
1460                                 (readpos[0] & 0x80) ? "Yes" : "No");
1461                 debug_log(DBG_SENSE, "EOP - %s\n",
1462                                 (readpos[0] & 0x40) ? "Yes" : "No");
1463
1464                 if (readpos[0] & 0x4) {
1465                         printk(KERN_INFO "ide-tape: Block location is unknown"
1466                                          "to the tape\n");
1467                         clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
1468                         idetape_end_request(drive, 0, 0);
1469                 } else {
1470                         debug_log(DBG_SENSE, "Block Location - %u\n",
1471                                         be32_to_cpu(*(u32 *)&readpos[4]));
1472
1473                         tape->partition = readpos[1];
1474                         tape->first_frame =
1475                                 be32_to_cpu(*(u32 *)&readpos[4]);
1476                         set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
1477                         idetape_end_request(drive, 1, 0);
1478                 }
1479         } else {
1480                 idetape_end_request(drive, 0, 0);
1481         }
1482         return ide_stopped;
1483 }
1484
1485 /*
1486  * Write a filemark if write_filemark=1. Flush the device buffers without
1487  * writing a filemark otherwise.
1488  */
1489 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1490                 struct ide_atapi_pc *pc, int write_filemark)
1491 {
1492         idetape_init_pc(pc);
1493         pc->c[0] = WRITE_FILEMARKS;
1494         pc->c[4] = write_filemark;
1495         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1496         pc->idetape_callback = &idetape_pc_callback;
1497 }
1498
1499 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1500 {
1501         idetape_init_pc(pc);
1502         pc->c[0] = TEST_UNIT_READY;
1503         pc->idetape_callback = &idetape_pc_callback;
1504 }
1505
1506 /*
1507  * We add a special packet command request to the tail of the request queue, and
1508  * wait for it to be serviced. This is not to be called from within the request
1509  * handling part of the driver! We allocate here data on the stack and it is
1510  * valid until the request is finished. This is not the case for the bottom part
1511  * of the driver, where we are always leaving the functions to wait for an
1512  * interrupt or a timer event.
1513  *
1514  * From the bottom part of the driver, we should allocate safe memory using
1515  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1516  * to the request list without waiting for it to be serviced! In that case, we
1517  * usually use idetape_queue_pc_head().
1518  */
1519 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1520 {
1521         struct ide_tape_obj *tape = drive->driver_data;
1522         struct request rq;
1523
1524         idetape_init_rq(&rq, REQ_IDETAPE_PC1);
1525         rq.buffer = (char *) pc;
1526         rq.rq_disk = tape->disk;
1527         return ide_do_drive_cmd(drive, &rq, ide_wait);
1528 }
1529
1530 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1531                 struct ide_atapi_pc *pc, int cmd)
1532 {
1533         idetape_init_pc(pc);
1534         pc->c[0] = START_STOP;
1535         pc->c[4] = cmd;
1536         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1537         pc->idetape_callback = &idetape_pc_callback;
1538 }
1539
1540 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1541 {
1542         idetape_tape_t *tape = drive->driver_data;
1543         struct ide_atapi_pc pc;
1544         int load_attempted = 0;
1545
1546         /* Wait for the tape to become ready */
1547         set_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
1548         timeout += jiffies;
1549         while (time_before(jiffies, timeout)) {
1550                 idetape_create_test_unit_ready_cmd(&pc);
1551                 if (!idetape_queue_pc_tail(drive, &pc))
1552                         return 0;
1553                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1554                     || (tape->asc == 0x3A)) {
1555                         /* no media */
1556                         if (load_attempted)
1557                                 return -ENOMEDIUM;
1558                         idetape_create_load_unload_cmd(drive, &pc,
1559                                                         IDETAPE_LU_LOAD_MASK);
1560                         idetape_queue_pc_tail(drive, &pc);
1561                         load_attempted = 1;
1562                 /* not about to be ready */
1563                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1564                              (tape->ascq == 1 || tape->ascq == 8)))
1565                         return -EIO;
1566                 msleep(100);
1567         }
1568         return -EIO;
1569 }
1570
1571 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1572 {
1573         struct ide_atapi_pc pc;
1574         int rc;
1575
1576         idetape_create_write_filemark_cmd(drive, &pc, 0);
1577         rc = idetape_queue_pc_tail(drive, &pc);
1578         if (rc)
1579                 return rc;
1580         idetape_wait_ready(drive, 60 * 5 * HZ);
1581         return 0;
1582 }
1583
1584 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1585 {
1586         idetape_init_pc(pc);
1587         pc->c[0] = READ_POSITION;
1588         pc->req_xfer = 20;
1589         pc->idetape_callback = &idetape_read_position_callback;
1590 }
1591
1592 static int idetape_read_position(ide_drive_t *drive)
1593 {
1594         idetape_tape_t *tape = drive->driver_data;
1595         struct ide_atapi_pc pc;
1596         int position;
1597
1598         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1599
1600         idetape_create_read_position_cmd(&pc);
1601         if (idetape_queue_pc_tail(drive, &pc))
1602                 return -1;
1603         position = tape->first_frame;
1604         return position;
1605 }
1606
1607 static void idetape_create_locate_cmd(ide_drive_t *drive,
1608                 struct ide_atapi_pc *pc,
1609                 unsigned int block, u8 partition, int skip)
1610 {
1611         idetape_init_pc(pc);
1612         pc->c[0] = POSITION_TO_ELEMENT;
1613         pc->c[1] = 2;
1614         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1615         pc->c[8] = partition;
1616         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1617         pc->idetape_callback = &idetape_pc_callback;
1618 }
1619
1620 static int idetape_create_prevent_cmd(ide_drive_t *drive,
1621                 struct ide_atapi_pc *pc, int prevent)
1622 {
1623         idetape_tape_t *tape = drive->driver_data;
1624
1625         /* device supports locking according to capabilities page */
1626         if (!(tape->caps[6] & 0x01))
1627                 return 0;
1628
1629         idetape_init_pc(pc);
1630         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
1631         pc->c[4] = prevent;
1632         pc->idetape_callback = &idetape_pc_callback;
1633         return 1;
1634 }
1635
1636 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1637 {
1638         idetape_tape_t *tape = drive->driver_data;
1639
1640         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1641                 return;
1642
1643         clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
1644         tape->merge_bh_size = 0;
1645         if (tape->merge_bh != NULL) {
1646                 ide_tape_kfree_buffer(tape);
1647                 tape->merge_bh = NULL;
1648         }
1649
1650         tape->chrdev_dir = IDETAPE_DIR_NONE;
1651 }
1652
1653 /*
1654  * Position the tape to the requested block using the LOCATE packet command.
1655  * A READ POSITION command is then issued to check where we are positioned. Like
1656  * all higher level operations, we queue the commands at the tail of the request
1657  * queue and wait for their completion.
1658  */
1659 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1660                 u8 partition, int skip)
1661 {
1662         idetape_tape_t *tape = drive->driver_data;
1663         int retval;
1664         struct ide_atapi_pc pc;
1665
1666         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1667                 __ide_tape_discard_merge_buffer(drive);
1668         idetape_wait_ready(drive, 60 * 5 * HZ);
1669         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1670         retval = idetape_queue_pc_tail(drive, &pc);
1671         if (retval)
1672                 return (retval);
1673
1674         idetape_create_read_position_cmd(&pc);
1675         return (idetape_queue_pc_tail(drive, &pc));
1676 }
1677
1678 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1679                                           int restore_position)
1680 {
1681         idetape_tape_t *tape = drive->driver_data;
1682         int seek, position;
1683
1684         __ide_tape_discard_merge_buffer(drive);
1685         if (restore_position) {
1686                 position = idetape_read_position(drive);
1687                 seek = position > 0 ? position : 0;
1688                 if (idetape_position_tape(drive, seek, 0, 0)) {
1689                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1690                                          " %s\n", tape->name, __func__);
1691                         return;
1692                 }
1693         }
1694 }
1695
1696 /*
1697  * Generate a read/write request for the block device interface and wait for it
1698  * to be serviced.
1699  */
1700 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1701                                  struct idetape_bh *bh)
1702 {
1703         idetape_tape_t *tape = drive->driver_data;
1704         struct request rq;
1705
1706         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1707
1708         idetape_init_rq(&rq, cmd);
1709         rq.rq_disk = tape->disk;
1710         rq.special = (void *)bh;
1711         rq.sector = tape->first_frame;
1712         rq.nr_sectors           = blocks;
1713         rq.current_nr_sectors   = blocks;
1714         (void) ide_do_drive_cmd(drive, &rq, ide_wait);
1715
1716         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1717                 return 0;
1718
1719         if (tape->merge_bh)
1720                 idetape_init_merge_buffer(tape);
1721         if (rq.errors == IDETAPE_ERROR_GENERAL)
1722                 return -EIO;
1723         return (tape->blk_size * (blocks-rq.current_nr_sectors));
1724 }
1725
1726 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1727 {
1728         idetape_init_pc(pc);
1729         pc->c[0] = INQUIRY;
1730         pc->c[4] = 254;
1731         pc->req_xfer = 254;
1732         pc->idetape_callback = &idetape_pc_callback;
1733 }
1734
1735 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1736                 struct ide_atapi_pc *pc)
1737 {
1738         idetape_init_pc(pc);
1739         pc->c[0] = REZERO_UNIT;
1740         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1741         pc->idetape_callback = &idetape_pc_callback;
1742 }
1743
1744 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1745 {
1746         idetape_init_pc(pc);
1747         pc->c[0] = ERASE;
1748         pc->c[1] = 1;
1749         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1750         pc->idetape_callback = &idetape_pc_callback;
1751 }
1752
1753 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1754 {
1755         idetape_init_pc(pc);
1756         pc->c[0] = SPACE;
1757         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1758         pc->c[1] = cmd;
1759         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1760         pc->idetape_callback = &idetape_pc_callback;
1761 }
1762
1763 /* Queue up a character device originated write request. */
1764 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1765 {
1766         idetape_tape_t *tape = drive->driver_data;
1767
1768         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1769
1770         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1771                                      blocks, tape->merge_bh);
1772 }
1773
1774 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1775 {
1776         idetape_tape_t *tape = drive->driver_data;
1777         int blocks, min;
1778         struct idetape_bh *bh;
1779
1780         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1781                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1782                                 " but we are not writing.\n");
1783                 return;
1784         }
1785         if (tape->merge_bh_size > tape->buffer_size) {
1786                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1787                 tape->merge_bh_size = tape->buffer_size;
1788         }
1789         if (tape->merge_bh_size) {
1790                 blocks = tape->merge_bh_size / tape->blk_size;
1791                 if (tape->merge_bh_size % tape->blk_size) {
1792                         unsigned int i;
1793
1794                         blocks++;
1795                         i = tape->blk_size - tape->merge_bh_size %
1796                                 tape->blk_size;
1797                         bh = tape->bh->b_reqnext;
1798                         while (bh) {
1799                                 atomic_set(&bh->b_count, 0);
1800                                 bh = bh->b_reqnext;
1801                         }
1802                         bh = tape->bh;
1803                         while (i) {
1804                                 if (bh == NULL) {
1805                                         printk(KERN_INFO "ide-tape: bug,"
1806                                                          " bh NULL\n");
1807                                         break;
1808                                 }
1809                                 min = min(i, (unsigned int)(bh->b_size -
1810                                                 atomic_read(&bh->b_count)));
1811                                 memset(bh->b_data + atomic_read(&bh->b_count),
1812                                                 0, min);
1813                                 atomic_add(min, &bh->b_count);
1814                                 i -= min;
1815                                 bh = bh->b_reqnext;
1816                         }
1817                 }
1818                 (void) idetape_add_chrdev_write_request(drive, blocks);
1819                 tape->merge_bh_size = 0;
1820         }
1821         if (tape->merge_bh != NULL) {
1822                 ide_tape_kfree_buffer(tape);
1823                 tape->merge_bh = NULL;
1824         }
1825         tape->chrdev_dir = IDETAPE_DIR_NONE;
1826 }
1827
1828 static int idetape_init_read(ide_drive_t *drive)
1829 {
1830         idetape_tape_t *tape = drive->driver_data;
1831         int bytes_read;
1832
1833         /* Initialize read operation */
1834         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1835                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1836                         ide_tape_flush_merge_buffer(drive);
1837                         idetape_flush_tape_buffers(drive);
1838                 }
1839                 if (tape->merge_bh || tape->merge_bh_size) {
1840                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1841                                          " 0 now\n");
1842                         tape->merge_bh_size = 0;
1843                 }
1844                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1845                 if (!tape->merge_bh)
1846                         return -ENOMEM;
1847                 tape->chrdev_dir = IDETAPE_DIR_READ;
1848
1849                 /*
1850                  * Issue a read 0 command to ensure that DSC handshake is
1851                  * switched from completion mode to buffer available mode.
1852                  * No point in issuing this if DSC overlap isn't supported, some
1853                  * drives (Seagate STT3401A) will return an error.
1854                  */
1855                 if (drive->dsc_overlap) {
1856                         bytes_read = idetape_queue_rw_tail(drive,
1857                                                         REQ_IDETAPE_READ, 0,
1858                                                         tape->merge_bh);
1859                         if (bytes_read < 0) {
1860                                 ide_tape_kfree_buffer(tape);
1861                                 tape->merge_bh = NULL;
1862                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1863                                 return bytes_read;
1864                         }
1865                 }
1866         }
1867
1868         return 0;
1869 }
1870
1871 /* called from idetape_chrdev_read() to service a chrdev read request. */
1872 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1873 {
1874         idetape_tape_t *tape = drive->driver_data;
1875
1876         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1877
1878         /* If we are at a filemark, return a read length of 0 */
1879         if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1880                 return 0;
1881
1882         idetape_init_read(drive);
1883
1884         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1885                                      tape->merge_bh);
1886 }
1887
1888 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1889 {
1890         idetape_tape_t *tape = drive->driver_data;
1891         struct idetape_bh *bh;
1892         int blocks;
1893
1894         while (bcount) {
1895                 unsigned int count;
1896
1897                 bh = tape->merge_bh;
1898                 count = min(tape->buffer_size, bcount);
1899                 bcount -= count;
1900                 blocks = count / tape->blk_size;
1901                 while (count) {
1902                         atomic_set(&bh->b_count,
1903                                    min(count, (unsigned int)bh->b_size));
1904                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1905                         count -= atomic_read(&bh->b_count);
1906                         bh = bh->b_reqnext;
1907                 }
1908                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1909                                       tape->merge_bh);
1910         }
1911 }
1912
1913 /*
1914  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1915  * currently support only one partition.
1916  */
1917 static int idetape_rewind_tape(ide_drive_t *drive)
1918 {
1919         int retval;
1920         struct ide_atapi_pc pc;
1921         idetape_tape_t *tape;
1922         tape = drive->driver_data;
1923
1924         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1925
1926         idetape_create_rewind_cmd(drive, &pc);
1927         retval = idetape_queue_pc_tail(drive, &pc);
1928         if (retval)
1929                 return retval;
1930
1931         idetape_create_read_position_cmd(&pc);
1932         retval = idetape_queue_pc_tail(drive, &pc);
1933         if (retval)
1934                 return retval;
1935         return 0;
1936 }
1937
1938 /* mtio.h compatible commands should be issued to the chrdev interface. */
1939 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1940                                 unsigned long arg)
1941 {
1942         idetape_tape_t *tape = drive->driver_data;
1943         void __user *argp = (void __user *)arg;
1944
1945         struct idetape_config {
1946                 int dsc_rw_frequency;
1947                 int dsc_media_access_frequency;
1948                 int nr_stages;
1949         } config;
1950
1951         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1952
1953         switch (cmd) {
1954         case 0x0340:
1955                 if (copy_from_user(&config, argp, sizeof(config)))
1956                         return -EFAULT;
1957                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1958                 break;
1959         case 0x0350:
1960                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1961                 config.nr_stages = 1;
1962                 if (copy_to_user(argp, &config, sizeof(config)))
1963                         return -EFAULT;
1964                 break;
1965         default:
1966                 return -EIO;
1967         }
1968         return 0;
1969 }
1970
1971 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1972                                         int mt_count)
1973 {
1974         idetape_tape_t *tape = drive->driver_data;
1975         struct ide_atapi_pc pc;
1976         int retval, count = 0;
1977         int sprev = !!(tape->caps[4] & 0x20);
1978
1979         if (mt_count == 0)
1980                 return 0;
1981         if (MTBSF == mt_op || MTBSFM == mt_op) {
1982                 if (!sprev)
1983                         return -EIO;
1984                 mt_count = -mt_count;
1985         }
1986
1987         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1988                 tape->merge_bh_size = 0;
1989                 if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1990                         ++count;
1991                 ide_tape_discard_merge_buffer(drive, 0);
1992         }
1993
1994         switch (mt_op) {
1995         case MTFSF:
1996         case MTBSF:
1997                 idetape_create_space_cmd(&pc, mt_count - count,
1998                                          IDETAPE_SPACE_OVER_FILEMARK);
1999                 return idetape_queue_pc_tail(drive, &pc);
2000         case MTFSFM:
2001         case MTBSFM:
2002                 if (!sprev)
2003                         return -EIO;
2004                 retval = idetape_space_over_filemarks(drive, MTFSF,
2005                                                       mt_count - count);
2006                 if (retval)
2007                         return retval;
2008                 count = (MTBSFM == mt_op ? 1 : -1);
2009                 return idetape_space_over_filemarks(drive, MTFSF, count);
2010         default:
2011                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2012                                 mt_op);
2013                 return -EIO;
2014         }
2015 }
2016
2017 /*
2018  * Our character device read / write functions.
2019  *
2020  * The tape is optimized to maximize throughput when it is transferring an
2021  * integral number of the "continuous transfer limit", which is a parameter of
2022  * the specific tape (26kB on my particular tape, 32kB for Onstream).
2023  *
2024  * As of version 1.3 of the driver, the character device provides an abstract
2025  * continuous view of the media - any mix of block sizes (even 1 byte) on the
2026  * same backup/restore procedure is supported. The driver will internally
2027  * convert the requests to the recommended transfer unit, so that an unmatch
2028  * between the user's block size to the recommended size will only result in a
2029  * (slightly) increased driver overhead, but will no longer hit performance.
2030  * This is not applicable to Onstream.
2031  */
2032 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
2033                                    size_t count, loff_t *ppos)
2034 {
2035         struct ide_tape_obj *tape = ide_tape_f(file);
2036         ide_drive_t *drive = tape->drive;
2037         ssize_t bytes_read, temp, actually_read = 0, rc;
2038         ssize_t ret = 0;
2039         u16 ctl = *(u16 *)&tape->caps[12];
2040
2041         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2042
2043         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
2044                 if (test_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags))
2045                         if (count > tape->blk_size &&
2046                             (count % tape->blk_size) == 0)
2047                                 tape->user_bs_factor = count / tape->blk_size;
2048         }
2049         rc = idetape_init_read(drive);
2050         if (rc < 0)
2051                 return rc;
2052         if (count == 0)
2053                 return (0);
2054         if (tape->merge_bh_size) {
2055                 actually_read = min((unsigned int)(tape->merge_bh_size),
2056                                     (unsigned int)count);
2057                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
2058                         ret = -EFAULT;
2059                 buf += actually_read;
2060                 tape->merge_bh_size -= actually_read;
2061                 count -= actually_read;
2062         }
2063         while (count >= tape->buffer_size) {
2064                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2065                 if (bytes_read <= 0)
2066                         goto finish;
2067                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
2068                         ret = -EFAULT;
2069                 buf += bytes_read;
2070                 count -= bytes_read;
2071                 actually_read += bytes_read;
2072         }
2073         if (count) {
2074                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2075                 if (bytes_read <= 0)
2076                         goto finish;
2077                 temp = min((unsigned long)count, (unsigned long)bytes_read);
2078                 if (idetape_copy_stage_to_user(tape, buf, temp))
2079                         ret = -EFAULT;
2080                 actually_read += temp;
2081                 tape->merge_bh_size = bytes_read-temp;
2082         }
2083 finish:
2084         if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
2085                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
2086
2087                 idetape_space_over_filemarks(drive, MTFSF, 1);
2088                 return 0;
2089         }
2090
2091         return ret ? ret : actually_read;
2092 }
2093
2094 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
2095                                      size_t count, loff_t *ppos)
2096 {
2097         struct ide_tape_obj *tape = ide_tape_f(file);
2098         ide_drive_t *drive = tape->drive;
2099         ssize_t actually_written = 0;
2100         ssize_t ret = 0;
2101         u16 ctl = *(u16 *)&tape->caps[12];
2102
2103         /* The drive is write protected. */
2104         if (tape->write_prot)
2105                 return -EACCES;
2106
2107         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2108
2109         /* Initialize write operation */
2110         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2111                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2112                         ide_tape_discard_merge_buffer(drive, 1);
2113                 if (tape->merge_bh || tape->merge_bh_size) {
2114                         printk(KERN_ERR "ide-tape: merge_bh_size "
2115                                 "should be 0 now\n");
2116                         tape->merge_bh_size = 0;
2117                 }
2118                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
2119                 if (!tape->merge_bh)
2120                         return -ENOMEM;
2121                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
2122                 idetape_init_merge_buffer(tape);
2123
2124                 /*
2125                  * Issue a write 0 command to ensure that DSC handshake is
2126                  * switched from completion mode to buffer available mode. No
2127                  * point in issuing this if DSC overlap isn't supported, some
2128                  * drives (Seagate STT3401A) will return an error.
2129                  */
2130                 if (drive->dsc_overlap) {
2131                         ssize_t retval = idetape_queue_rw_tail(drive,
2132                                                         REQ_IDETAPE_WRITE, 0,
2133                                                         tape->merge_bh);
2134                         if (retval < 0) {
2135                                 ide_tape_kfree_buffer(tape);
2136                                 tape->merge_bh = NULL;
2137                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2138                                 return retval;
2139                         }
2140                 }
2141         }
2142         if (count == 0)
2143                 return (0);
2144         if (tape->merge_bh_size) {
2145                 if (tape->merge_bh_size >= tape->buffer_size) {
2146                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
2147                         tape->merge_bh_size = 0;
2148                 }
2149                 actually_written = min((unsigned int)
2150                                 (tape->buffer_size - tape->merge_bh_size),
2151                                 (unsigned int)count);
2152                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
2153                                 ret = -EFAULT;
2154                 buf += actually_written;
2155                 tape->merge_bh_size += actually_written;
2156                 count -= actually_written;
2157
2158                 if (tape->merge_bh_size == tape->buffer_size) {
2159                         ssize_t retval;
2160                         tape->merge_bh_size = 0;
2161                         retval = idetape_add_chrdev_write_request(drive, ctl);
2162                         if (retval <= 0)
2163                                 return (retval);
2164                 }
2165         }
2166         while (count >= tape->buffer_size) {
2167                 ssize_t retval;
2168                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
2169                         ret = -EFAULT;
2170                 buf += tape->buffer_size;
2171                 count -= tape->buffer_size;
2172                 retval = idetape_add_chrdev_write_request(drive, ctl);
2173                 actually_written += tape->buffer_size;
2174                 if (retval <= 0)
2175                         return (retval);
2176         }
2177         if (count) {
2178                 actually_written += count;
2179                 if (idetape_copy_stage_from_user(tape, buf, count))
2180                         ret = -EFAULT;
2181                 tape->merge_bh_size += count;
2182         }
2183         return ret ? ret : actually_written;
2184 }
2185
2186 static int idetape_write_filemark(ide_drive_t *drive)
2187 {
2188         struct ide_atapi_pc pc;
2189
2190         /* Write a filemark */
2191         idetape_create_write_filemark_cmd(drive, &pc, 1);
2192         if (idetape_queue_pc_tail(drive, &pc)) {
2193                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
2194                 return -EIO;
2195         }
2196         return 0;
2197 }
2198
2199 /*
2200  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
2201  * requested.
2202  *
2203  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
2204  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
2205  * usually not supported.
2206  *
2207  * The following commands are currently not supported:
2208  *
2209  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
2210  * MT_ST_WRITE_THRESHOLD.
2211  */
2212 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
2213 {
2214         idetape_tape_t *tape = drive->driver_data;
2215         struct ide_atapi_pc pc;
2216         int i, retval;
2217
2218         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
2219                         mt_op, mt_count);
2220
2221         switch (mt_op) {
2222         case MTFSF:
2223         case MTFSFM:
2224         case MTBSF:
2225         case MTBSFM:
2226                 if (!mt_count)
2227                         return 0;
2228                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
2229         default:
2230                 break;
2231         }
2232
2233         switch (mt_op) {
2234         case MTWEOF:
2235                 if (tape->write_prot)
2236                         return -EACCES;
2237                 ide_tape_discard_merge_buffer(drive, 1);
2238                 for (i = 0; i < mt_count; i++) {
2239                         retval = idetape_write_filemark(drive);
2240                         if (retval)
2241                                 return retval;
2242                 }
2243                 return 0;
2244         case MTREW:
2245                 ide_tape_discard_merge_buffer(drive, 0);
2246                 if (idetape_rewind_tape(drive))
2247                         return -EIO;
2248                 return 0;
2249         case MTLOAD:
2250                 ide_tape_discard_merge_buffer(drive, 0);
2251                 idetape_create_load_unload_cmd(drive, &pc,
2252                                                IDETAPE_LU_LOAD_MASK);
2253                 return idetape_queue_pc_tail(drive, &pc);
2254         case MTUNLOAD:
2255         case MTOFFL:
2256                 /*
2257                  * If door is locked, attempt to unlock before
2258                  * attempting to eject.
2259                  */
2260                 if (tape->door_locked) {
2261                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2262                                 if (!idetape_queue_pc_tail(drive, &pc))
2263                                         tape->door_locked = DOOR_UNLOCKED;
2264                 }
2265                 ide_tape_discard_merge_buffer(drive, 0);
2266                 idetape_create_load_unload_cmd(drive, &pc,
2267                                               !IDETAPE_LU_LOAD_MASK);
2268                 retval = idetape_queue_pc_tail(drive, &pc);
2269                 if (!retval)
2270                         clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
2271                 return retval;
2272         case MTNOP:
2273                 ide_tape_discard_merge_buffer(drive, 0);
2274                 return idetape_flush_tape_buffers(drive);
2275         case MTRETEN:
2276                 ide_tape_discard_merge_buffer(drive, 0);
2277                 idetape_create_load_unload_cmd(drive, &pc,
2278                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2279                 return idetape_queue_pc_tail(drive, &pc);
2280         case MTEOM:
2281                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
2282                 return idetape_queue_pc_tail(drive, &pc);
2283         case MTERASE:
2284                 (void)idetape_rewind_tape(drive);
2285                 idetape_create_erase_cmd(&pc);
2286                 return idetape_queue_pc_tail(drive, &pc);
2287         case MTSETBLK:
2288                 if (mt_count) {
2289                         if (mt_count < tape->blk_size ||
2290                             mt_count % tape->blk_size)
2291                                 return -EIO;
2292                         tape->user_bs_factor = mt_count / tape->blk_size;
2293                         clear_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2294                 } else
2295                         set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2296                 return 0;
2297         case MTSEEK:
2298                 ide_tape_discard_merge_buffer(drive, 0);
2299                 return idetape_position_tape(drive,
2300                         mt_count * tape->user_bs_factor, tape->partition, 0);
2301         case MTSETPART:
2302                 ide_tape_discard_merge_buffer(drive, 0);
2303                 return idetape_position_tape(drive, 0, mt_count, 0);
2304         case MTFSR:
2305         case MTBSR:
2306         case MTLOCK:
2307                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
2308                         return 0;
2309                 retval = idetape_queue_pc_tail(drive, &pc);
2310                 if (retval)
2311                         return retval;
2312                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
2313                 return 0;
2314         case MTUNLOCK:
2315                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
2316                         return 0;
2317                 retval = idetape_queue_pc_tail(drive, &pc);
2318                 if (retval)
2319                         return retval;
2320                 tape->door_locked = DOOR_UNLOCKED;
2321                 return 0;
2322         default:
2323                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2324                                 mt_op);
2325                 return -EIO;
2326         }
2327 }
2328
2329 /*
2330  * Our character device ioctls. General mtio.h magnetic io commands are
2331  * supported here, and not in the corresponding block interface. Our own
2332  * ide-tape ioctls are supported on both interfaces.
2333  */
2334 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
2335                                 unsigned int cmd, unsigned long arg)
2336 {
2337         struct ide_tape_obj *tape = ide_tape_f(file);
2338         ide_drive_t *drive = tape->drive;
2339         struct mtop mtop;
2340         struct mtget mtget;
2341         struct mtpos mtpos;
2342         int block_offset = 0, position = tape->first_frame;
2343         void __user *argp = (void __user *)arg;
2344
2345         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
2346
2347         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2348                 ide_tape_flush_merge_buffer(drive);
2349                 idetape_flush_tape_buffers(drive);
2350         }
2351         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
2352                 block_offset = tape->merge_bh_size /
2353                         (tape->blk_size * tape->user_bs_factor);
2354                 position = idetape_read_position(drive);
2355                 if (position < 0)
2356                         return -EIO;
2357         }
2358         switch (cmd) {
2359         case MTIOCTOP:
2360                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
2361                         return -EFAULT;
2362                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
2363         case MTIOCGET:
2364                 memset(&mtget, 0, sizeof(struct mtget));
2365                 mtget.mt_type = MT_ISSCSI2;
2366                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
2367                 mtget.mt_dsreg =
2368                         ((tape->blk_size * tape->user_bs_factor)
2369                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
2370
2371                 if (tape->drv_write_prot)
2372                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
2373
2374                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
2375                         return -EFAULT;
2376                 return 0;
2377         case MTIOCPOS:
2378                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
2379                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
2380                         return -EFAULT;
2381                 return 0;
2382         default:
2383                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2384                         ide_tape_discard_merge_buffer(drive, 1);
2385                 return idetape_blkdev_ioctl(drive, cmd, arg);
2386         }
2387 }
2388
2389 /*
2390  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
2391  * block size with the reported value.
2392  */
2393 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
2394 {
2395         idetape_tape_t *tape = drive->driver_data;
2396         struct ide_atapi_pc pc;
2397
2398         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
2399         if (idetape_queue_pc_tail(drive, &pc)) {
2400                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
2401                 if (tape->blk_size == 0) {
2402                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
2403                                             "block size, assuming 32k\n");
2404                         tape->blk_size = 32768;
2405                 }
2406                 return;
2407         }
2408         tape->blk_size = (pc.buf[4 + 5] << 16) +
2409                                 (pc.buf[4 + 6] << 8)  +
2410                                  pc.buf[4 + 7];
2411         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
2412 }
2413
2414 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
2415 {
2416         unsigned int minor = iminor(inode), i = minor & ~0xc0;
2417         ide_drive_t *drive;
2418         idetape_tape_t *tape;
2419         struct ide_atapi_pc pc;
2420         int retval;
2421
2422         if (i >= MAX_HWIFS * MAX_DRIVES)
2423                 return -ENXIO;
2424
2425         tape = ide_tape_chrdev_get(i);
2426         if (!tape)
2427                 return -ENXIO;
2428
2429         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2430
2431         /*
2432          * We really want to do nonseekable_open(inode, filp); here, but some
2433          * versions of tar incorrectly call lseek on tapes and bail out if that
2434          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
2435          */
2436         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
2437
2438         drive = tape->drive;
2439
2440         filp->private_data = tape;
2441
2442         if (test_and_set_bit(IDETAPE_FLAG_BUSY, &tape->flags)) {
2443                 retval = -EBUSY;
2444                 goto out_put_tape;
2445         }
2446
2447         retval = idetape_wait_ready(drive, 60 * HZ);
2448         if (retval) {
2449                 clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2450                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
2451                 goto out_put_tape;
2452         }
2453
2454         idetape_read_position(drive);
2455         if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
2456                 (void)idetape_rewind_tape(drive);
2457
2458         /* Read block size and write protect status from drive. */
2459         ide_tape_get_bsize_from_bdesc(drive);
2460
2461         /* Set write protect flag if device is opened as read-only. */
2462         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
2463                 tape->write_prot = 1;
2464         else
2465                 tape->write_prot = tape->drv_write_prot;
2466
2467         /* Make sure drive isn't write protected if user wants to write. */
2468         if (tape->write_prot) {
2469                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
2470                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
2471                         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2472                         retval = -EROFS;
2473                         goto out_put_tape;
2474                 }
2475         }
2476
2477         /* Lock the tape drive door so user can't eject. */
2478         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2479                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
2480                         if (!idetape_queue_pc_tail(drive, &pc)) {
2481                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2482                                         tape->door_locked = DOOR_LOCKED;
2483                         }
2484                 }
2485         }
2486         return 0;
2487
2488 out_put_tape:
2489         ide_tape_put(tape);
2490         return retval;
2491 }
2492
2493 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2494 {
2495         idetape_tape_t *tape = drive->driver_data;
2496
2497         ide_tape_flush_merge_buffer(drive);
2498         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2499         if (tape->merge_bh != NULL) {
2500                 idetape_pad_zeros(drive, tape->blk_size *
2501                                 (tape->user_bs_factor - 1));
2502                 ide_tape_kfree_buffer(tape);
2503                 tape->merge_bh = NULL;
2504         }
2505         idetape_write_filemark(drive);
2506         idetape_flush_tape_buffers(drive);
2507         idetape_flush_tape_buffers(drive);
2508 }
2509
2510 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2511 {
2512         struct ide_tape_obj *tape = ide_tape_f(filp);
2513         ide_drive_t *drive = tape->drive;
2514         struct ide_atapi_pc pc;
2515         unsigned int minor = iminor(inode);
2516
2517         lock_kernel();
2518         tape = drive->driver_data;
2519
2520         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2521
2522         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2523                 idetape_write_release(drive, minor);
2524         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2525                 if (minor < 128)
2526                         ide_tape_discard_merge_buffer(drive, 1);
2527         }
2528
2529         if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
2530                 (void) idetape_rewind_tape(drive);
2531         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2532                 if (tape->door_locked == DOOR_LOCKED) {
2533                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
2534                                 if (!idetape_queue_pc_tail(drive, &pc))
2535                                         tape->door_locked = DOOR_UNLOCKED;
2536                         }
2537                 }
2538         }
2539         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2540         ide_tape_put(tape);
2541         unlock_kernel();
2542         return 0;
2543 }
2544
2545 /*
2546  * check the contents of the ATAPI IDENTIFY command results. We return:
2547  *
2548  * 1 - If the tape can be supported by us, based on the information we have so
2549  * far.
2550  *
2551  * 0 - If this tape driver is not currently supported by us.
2552  */
2553 static int idetape_identify_device(ide_drive_t *drive)
2554 {
2555         u8 gcw[2], protocol, device_type, removable, packet_size;
2556
2557         if (drive->id_read == 0)
2558                 return 1;
2559
2560         *((unsigned short *) &gcw) = drive->id->config;
2561
2562         protocol        =   (gcw[1] & 0xC0) >> 6;
2563         device_type     =    gcw[1] & 0x1F;
2564         removable       = !!(gcw[0] & 0x80);
2565         packet_size     =    gcw[0] & 0x3;
2566
2567         /* Check that we can support this device */
2568         if (protocol != 2)
2569                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
2570                                 protocol);
2571         else if (device_type != 1)
2572                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
2573                                 "to tape\n", device_type);
2574         else if (!removable)
2575                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
2576         else if (packet_size != 0) {
2577                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
2578                                 " bytes\n", packet_size);
2579         } else
2580                 return 1;
2581         return 0;
2582 }
2583
2584 static void idetape_get_inquiry_results(ide_drive_t *drive)
2585 {
2586         idetape_tape_t *tape = drive->driver_data;
2587         struct ide_atapi_pc pc;
2588         char fw_rev[6], vendor_id[10], product_id[18];
2589
2590         idetape_create_inquiry_cmd(&pc);
2591         if (idetape_queue_pc_tail(drive, &pc)) {
2592                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2593                                 tape->name);
2594                 return;
2595         }
2596         memcpy(vendor_id, &pc.buf[8], 8);
2597         memcpy(product_id, &pc.buf[16], 16);
2598         memcpy(fw_rev, &pc.buf[32], 4);
2599
2600         ide_fixstring(vendor_id, 10, 0);
2601         ide_fixstring(product_id, 18, 0);
2602         ide_fixstring(fw_rev, 6, 0);
2603
2604         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
2605                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2606 }
2607
2608 /*
2609  * Ask the tape about its various parameters. In particular, we will adjust our
2610  * data transfer buffer size to the recommended value as returned by the tape.
2611  */
2612 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2613 {
2614         idetape_tape_t *tape = drive->driver_data;
2615         struct ide_atapi_pc pc;
2616         u8 *caps;
2617         u8 speed, max_speed;
2618
2619         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2620         if (idetape_queue_pc_tail(drive, &pc)) {
2621                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2622                                 " some default values\n");
2623                 tape->blk_size = 512;
2624                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2625                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2626                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2627                 return;
2628         }
2629         caps = pc.buf + 4 + pc.buf[3];
2630
2631         /* convert to host order and save for later use */
2632         speed = be16_to_cpu(*(u16 *)&caps[14]);
2633         max_speed = be16_to_cpu(*(u16 *)&caps[8]);
2634
2635         put_unaligned(max_speed, (u16 *)&caps[8]);
2636         put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
2637         put_unaligned(speed, (u16 *)&caps[14]);
2638         put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
2639
2640         if (!speed) {
2641                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2642                                 "(assuming 650KB/sec)\n", drive->name);
2643                 put_unaligned(650, (u16 *)&caps[14]);
2644         }
2645         if (!max_speed) {
2646                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2647                                 "(assuming 650KB/sec)\n", drive->name);
2648                 put_unaligned(650, (u16 *)&caps[8]);
2649         }
2650
2651         memcpy(&tape->caps, caps, 20);
2652         if (caps[7] & 0x02)
2653                 tape->blk_size = 512;
2654         else if (caps[7] & 0x04)
2655                 tape->blk_size = 1024;
2656 }
2657
2658 #ifdef CONFIG_IDE_PROC_FS
2659 static void idetape_add_settings(ide_drive_t *drive)
2660 {
2661         idetape_tape_t *tape = drive->driver_data;
2662
2663         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2664                         1, 2, (u16 *)&tape->caps[16], NULL);
2665         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2666                         1, 1, (u16 *)&tape->caps[14], NULL);
2667         ide_add_setting(drive, "buffer_size", SETTING_READ, TYPE_INT, 0, 0xffff,
2668                         1, 1024, &tape->buffer_size, NULL);
2669         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
2670                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
2671                         NULL);
2672         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
2673                         1, &drive->dsc_overlap, NULL);
2674         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
2675                         1, 1, &tape->avg_speed, NULL);
2676         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
2677                         1, &tape->debug_mask, NULL);
2678 }
2679 #else
2680 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
2681 #endif
2682
2683 /*
2684  * The function below is called to:
2685  *
2686  * 1. Initialize our various state variables.
2687  * 2. Ask the tape for its capabilities.
2688  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2689  * is chosen based on the recommendation which we received in step 2.
2690  *
2691  * Note that at this point ide.c already assigned us an irq, so that we can
2692  * queue requests here and wait for their completion.
2693  */
2694 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2695 {
2696         unsigned long t;
2697         int speed;
2698         int buffer_size;
2699         u8 gcw[2];
2700         u16 *ctl = (u16 *)&tape->caps[12];
2701
2702         spin_lock_init(&tape->lock);
2703         drive->dsc_overlap = 1;
2704         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2705                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2706                                  tape->name);
2707                 drive->dsc_overlap = 0;
2708         }
2709         /* Seagate Travan drives do not support DSC overlap. */
2710         if (strstr(drive->id->model, "Seagate STT3401"))
2711                 drive->dsc_overlap = 0;
2712         tape->minor = minor;
2713         tape->name[0] = 'h';
2714         tape->name[1] = 't';
2715         tape->name[2] = '0' + minor;
2716         tape->chrdev_dir = IDETAPE_DIR_NONE;
2717         tape->pc = tape->pc_stack;
2718         *((unsigned short *) &gcw) = drive->id->config;
2719
2720         /* Command packet DRQ type */
2721         if (((gcw[0] & 0x60) >> 5) == 1)
2722                 set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
2723
2724         idetape_get_inquiry_results(drive);
2725         idetape_get_mode_sense_results(drive);
2726         ide_tape_get_bsize_from_bdesc(drive);
2727         tape->user_bs_factor = 1;
2728         tape->buffer_size = *ctl * tape->blk_size;
2729         while (tape->buffer_size > 0xffff) {
2730                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2731                 *ctl /= 2;
2732                 tape->buffer_size = *ctl * tape->blk_size;
2733         }
2734         buffer_size = tape->buffer_size;
2735         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2736         if (buffer_size % PAGE_SIZE) {
2737                 tape->pages_per_buffer++;
2738                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2739         }
2740
2741         /* select the "best" DSC read/write polling freq */
2742         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2743
2744         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2745
2746         /*
2747          * Ensure that the number we got makes sense; limit it within
2748          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2749          */
2750         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2751                                          IDETAPE_DSC_RW_MAX);
2752         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2753                 "%lums tDSC%s\n",
2754                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2755                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2756                 tape->buffer_size / 1024,
2757                 tape->best_dsc_rw_freq * 1000 / HZ,
2758                 drive->using_dma ? ", DMA":"");
2759
2760         idetape_add_settings(drive);
2761 }
2762
2763 static void ide_tape_remove(ide_drive_t *drive)
2764 {
2765         idetape_tape_t *tape = drive->driver_data;
2766
2767         ide_proc_unregister_driver(drive, tape->driver);
2768
2769         ide_unregister_region(tape->disk);
2770
2771         ide_tape_put(tape);
2772 }
2773
2774 static void ide_tape_release(struct kref *kref)
2775 {
2776         struct ide_tape_obj *tape = to_ide_tape(kref);
2777         ide_drive_t *drive = tape->drive;
2778         struct gendisk *g = tape->disk;
2779
2780         BUG_ON(tape->merge_bh_size);
2781
2782         drive->dsc_overlap = 0;
2783         drive->driver_data = NULL;
2784         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2785         device_destroy(idetape_sysfs_class,
2786                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2787         idetape_devs[tape->minor] = NULL;
2788         g->private_data = NULL;
2789         put_disk(g);
2790         kfree(tape);
2791 }
2792
2793 #ifdef CONFIG_IDE_PROC_FS
2794 static int proc_idetape_read_name
2795         (char *page, char **start, off_t off, int count, int *eof, void *data)
2796 {
2797         ide_drive_t     *drive = (ide_drive_t *) data;
2798         idetape_tape_t  *tape = drive->driver_data;
2799         char            *out = page;
2800         int             len;
2801
2802         len = sprintf(out, "%s\n", tape->name);
2803         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2804 }
2805
2806 static ide_proc_entry_t idetape_proc[] = {
2807         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2808         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2809         { NULL, 0, NULL, NULL }
2810 };
2811 #endif
2812
2813 static int ide_tape_probe(ide_drive_t *);
2814
2815 static ide_driver_t idetape_driver = {
2816         .gen_driver = {
2817                 .owner          = THIS_MODULE,
2818                 .name           = "ide-tape",
2819                 .bus            = &ide_bus_type,
2820         },
2821         .probe                  = ide_tape_probe,
2822         .remove                 = ide_tape_remove,
2823         .version                = IDETAPE_VERSION,
2824         .media                  = ide_tape,
2825         .supports_dsc_overlap   = 1,
2826         .do_request             = idetape_do_request,
2827         .end_request            = idetape_end_request,
2828         .error                  = __ide_error,
2829         .abort                  = __ide_abort,
2830 #ifdef CONFIG_IDE_PROC_FS
2831         .proc                   = idetape_proc,
2832 #endif
2833 };
2834
2835 /* Our character device supporting functions, passed to register_chrdev. */
2836 static const struct file_operations idetape_fops = {
2837         .owner          = THIS_MODULE,
2838         .read           = idetape_chrdev_read,
2839         .write          = idetape_chrdev_write,
2840         .ioctl          = idetape_chrdev_ioctl,
2841         .open           = idetape_chrdev_open,
2842         .release        = idetape_chrdev_release,
2843 };
2844
2845 static int idetape_open(struct inode *inode, struct file *filp)
2846 {
2847         struct gendisk *disk = inode->i_bdev->bd_disk;
2848         struct ide_tape_obj *tape;
2849
2850         tape = ide_tape_get(disk);
2851         if (!tape)
2852                 return -ENXIO;
2853
2854         return 0;
2855 }
2856
2857 static int idetape_release(struct inode *inode, struct file *filp)
2858 {
2859         struct gendisk *disk = inode->i_bdev->bd_disk;
2860         struct ide_tape_obj *tape = ide_tape_g(disk);
2861
2862         ide_tape_put(tape);
2863
2864         return 0;
2865 }
2866
2867 static int idetape_ioctl(struct inode *inode, struct file *file,
2868                         unsigned int cmd, unsigned long arg)
2869 {
2870         struct block_device *bdev = inode->i_bdev;
2871         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2872         ide_drive_t *drive = tape->drive;
2873         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2874         if (err == -EINVAL)
2875                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2876         return err;
2877 }
2878
2879 static struct block_device_operations idetape_block_ops = {
2880         .owner          = THIS_MODULE,
2881         .open           = idetape_open,
2882         .release        = idetape_release,
2883         .ioctl          = idetape_ioctl,
2884 };
2885
2886 static int ide_tape_probe(ide_drive_t *drive)
2887 {
2888         idetape_tape_t *tape;
2889         struct gendisk *g;
2890         int minor;
2891
2892         if (!strstr("ide-tape", drive->driver_req))
2893                 goto failed;
2894         if (!drive->present)
2895                 goto failed;
2896         if (drive->media != ide_tape)
2897                 goto failed;
2898         if (!idetape_identify_device(drive)) {
2899                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2900                                 " the driver\n", drive->name);
2901                 goto failed;
2902         }
2903         if (drive->scsi) {
2904                 printk(KERN_INFO "ide-tape: passing drive %s to ide-scsi"
2905                                  " emulation.\n", drive->name);
2906                 goto failed;
2907         }
2908         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2909         if (tape == NULL) {
2910                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2911                                 drive->name);
2912                 goto failed;
2913         }
2914
2915         g = alloc_disk(1 << PARTN_BITS);
2916         if (!g)
2917                 goto out_free_tape;
2918
2919         ide_init_disk(g, drive);
2920
2921         ide_proc_register_driver(drive, &idetape_driver);
2922
2923         kref_init(&tape->kref);
2924
2925         tape->drive = drive;
2926         tape->driver = &idetape_driver;
2927         tape->disk = g;
2928
2929         g->private_data = &tape->driver;
2930
2931         drive->driver_data = tape;
2932
2933         mutex_lock(&idetape_ref_mutex);
2934         for (minor = 0; idetape_devs[minor]; minor++)
2935                 ;
2936         idetape_devs[minor] = tape;
2937         mutex_unlock(&idetape_ref_mutex);
2938
2939         idetape_setup(drive, tape, minor);
2940
2941         device_create(idetape_sysfs_class, &drive->gendev,
2942                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
2943         device_create(idetape_sysfs_class, &drive->gendev,
2944                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
2945
2946         g->fops = &idetape_block_ops;
2947         ide_register_region(g);
2948
2949         return 0;
2950
2951 out_free_tape:
2952         kfree(tape);
2953 failed:
2954         return -ENODEV;
2955 }
2956
2957 static void __exit idetape_exit(void)
2958 {
2959         driver_unregister(&idetape_driver.gen_driver);
2960         class_destroy(idetape_sysfs_class);
2961         unregister_chrdev(IDETAPE_MAJOR, "ht");
2962 }
2963
2964 static int __init idetape_init(void)
2965 {
2966         int error = 1;
2967         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2968         if (IS_ERR(idetape_sysfs_class)) {
2969                 idetape_sysfs_class = NULL;
2970                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2971                 error = -EBUSY;
2972                 goto out;
2973         }
2974
2975         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2976                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2977                                 " interface\n");
2978                 error = -EBUSY;
2979                 goto out_free_class;
2980         }
2981
2982         error = driver_register(&idetape_driver.gen_driver);
2983         if (error)
2984                 goto out_free_driver;
2985
2986         return 0;
2987
2988 out_free_driver:
2989         driver_unregister(&idetape_driver.gen_driver);
2990 out_free_class:
2991         class_destroy(idetape_sysfs_class);
2992 out:
2993         return error;
2994 }
2995
2996 MODULE_ALIAS("ide:*m-tape*");
2997 module_init(idetape_init);
2998 module_exit(idetape_exit);
2999 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
3000 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
3001 MODULE_LICENSE("GPL");