ce9b6d327528a8cd5e57aa8ab1eb5b53318c35cd
[linux-2.6.git] / drivers / ide / ide-tape.c
1 /*
2  * IDE ATAPI streaming tape driver.
3  *
4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
6  *
7  * This driver was constructed as a student project in the software laboratory
8  * of the faculty of electrical engineering in the Technion - Israel's
9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
10  *
11  * It is hereby placed under the terms of the GNU general public license.
12  * (See linux/COPYING).
13  *
14  * For a historical changelog see
15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
16  */
17
18 #define IDETAPE_VERSION "1.20"
19
20 #include <linux/module.h>
21 #include <linux/types.h>
22 #include <linux/string.h>
23 #include <linux/kernel.h>
24 #include <linux/delay.h>
25 #include <linux/timer.h>
26 #include <linux/mm.h>
27 #include <linux/interrupt.h>
28 #include <linux/jiffies.h>
29 #include <linux/major.h>
30 #include <linux/errno.h>
31 #include <linux/genhd.h>
32 #include <linux/slab.h>
33 #include <linux/pci.h>
34 #include <linux/ide.h>
35 #include <linux/smp_lock.h>
36 #include <linux/completion.h>
37 #include <linux/bitops.h>
38 #include <linux/mutex.h>
39 #include <scsi/scsi.h>
40
41 #include <asm/byteorder.h>
42 #include <linux/irq.h>
43 #include <linux/uaccess.h>
44 #include <linux/io.h>
45 #include <asm/unaligned.h>
46 #include <linux/mtio.h>
47
48 enum {
49         /* output errors only */
50         DBG_ERR =               (1 << 0),
51         /* output all sense key/asc */
52         DBG_SENSE =             (1 << 1),
53         /* info regarding all chrdev-related procedures */
54         DBG_CHRDEV =            (1 << 2),
55         /* all remaining procedures */
56         DBG_PROCS =             (1 << 3),
57         /* buffer alloc info (pc_stack & rq_stack) */
58         DBG_PCRQ_STACK =        (1 << 4),
59 };
60
61 /* define to see debug info */
62 #define IDETAPE_DEBUG_LOG               0
63
64 #if IDETAPE_DEBUG_LOG
65 #define debug_log(lvl, fmt, args...)                    \
66 {                                                       \
67         if (tape->debug_mask & lvl)                     \
68         printk(KERN_INFO "ide-tape: " fmt, ## args);    \
69 }
70 #else
71 #define debug_log(lvl, fmt, args...) do {} while (0)
72 #endif
73
74 /**************************** Tunable parameters *****************************/
75 /*
76  * After each failed packet command we issue a request sense command and retry
77  * the packet command IDETAPE_MAX_PC_RETRIES times.
78  *
79  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
80  */
81 #define IDETAPE_MAX_PC_RETRIES          3
82
83 /*
84  * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
85  * bytes. This is used for several packet commands (Not for READ/WRITE commands)
86  */
87 #define IDETAPE_PC_BUFFER_SIZE          256
88
89 /*
90  *      In various places in the driver, we need to allocate storage
91  *      for packet commands and requests, which will remain valid while
92  *      we leave the driver to wait for an interrupt or a timeout event.
93  */
94 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
95
96 /*
97  * Some drives (for example, Seagate STT3401A Travan) require a very long
98  * timeout, because they don't return an interrupt or clear their busy bit
99  * until after the command completes (even retension commands).
100  */
101 #define IDETAPE_WAIT_CMD                (900*HZ)
102
103 /*
104  * The following parameter is used to select the point in the internal tape fifo
105  * in which we will start to refill the buffer. Decreasing the following
106  * parameter will improve the system's latency and interactive response, while
107  * using a high value might improve system throughput.
108  */
109 #define IDETAPE_FIFO_THRESHOLD          2
110
111 /*
112  * DSC polling parameters.
113  *
114  * Polling for DSC (a single bit in the status register) is a very important
115  * function in ide-tape. There are two cases in which we poll for DSC:
116  *
117  * 1. Before a read/write packet command, to ensure that we can transfer data
118  * from/to the tape's data buffers, without causing an actual media access.
119  * In case the tape is not ready yet, we take out our request from the device
120  * request queue, so that ide.c could service requests from the other device
121  * on the same interface in the meantime.
122  *
123  * 2. After the successful initialization of a "media access packet command",
124  * which is a command that can take a long time to complete (the interval can
125  * range from several seconds to even an hour). Again, we postpone our request
126  * in the middle to free the bus for the other device. The polling frequency
127  * here should be lower than the read/write frequency since those media access
128  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
129  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
130  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
131  *
132  * We also set a timeout for the timer, in case something goes wrong. The
133  * timeout should be longer then the maximum execution time of a tape operation.
134  */
135
136 /* DSC timings. */
137 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
138 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
139 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
140 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
141 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
142 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
143 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
144
145 /*************************** End of tunable parameters ***********************/
146
147 /* tape directions */
148 enum {
149         IDETAPE_DIR_NONE  = (1 << 0),
150         IDETAPE_DIR_READ  = (1 << 1),
151         IDETAPE_DIR_WRITE = (1 << 2),
152 };
153
154 struct idetape_bh {
155         u32 b_size;
156         atomic_t b_count;
157         struct idetape_bh *b_reqnext;
158         char *b_data;
159 };
160
161 /* Tape door status */
162 #define DOOR_UNLOCKED                   0
163 #define DOOR_LOCKED                     1
164 #define DOOR_EXPLICITLY_LOCKED          2
165
166 /* Some defines for the SPACE command */
167 #define IDETAPE_SPACE_OVER_FILEMARK     1
168 #define IDETAPE_SPACE_TO_EOD            3
169
170 /* Some defines for the LOAD UNLOAD command */
171 #define IDETAPE_LU_LOAD_MASK            1
172 #define IDETAPE_LU_RETENSION_MASK       2
173 #define IDETAPE_LU_EOT_MASK             4
174
175 /*
176  * Special requests for our block device strategy routine.
177  *
178  * In order to service a character device command, we add special requests to
179  * the tail of our block device request queue and wait for their completion.
180  */
181
182 enum {
183         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
184         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
185         REQ_IDETAPE_READ        = (1 << 2),
186         REQ_IDETAPE_WRITE       = (1 << 3),
187 };
188
189 /* Error codes returned in rq->errors to the higher part of the driver. */
190 #define IDETAPE_ERROR_GENERAL           101
191 #define IDETAPE_ERROR_FILEMARK          102
192 #define IDETAPE_ERROR_EOD               103
193
194 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
195 #define IDETAPE_BLOCK_DESCRIPTOR        0
196 #define IDETAPE_CAPABILITIES_PAGE       0x2a
197
198 /* Tape flag bits values. */
199 enum {
200         IDETAPE_FLAG_IGNORE_DSC         = (1 << 0),
201         /* 0 When the tape position is unknown */
202         IDETAPE_FLAG_ADDRESS_VALID      = (1 << 1),
203         /* Device already opened */
204         IDETAPE_FLAG_BUSY               = (1 << 2),
205         /* Attempt to auto-detect the current user block size */
206         IDETAPE_FLAG_DETECT_BS          = (1 << 3),
207         /* Currently on a filemark */
208         IDETAPE_FLAG_FILEMARK           = (1 << 4),
209         /* DRQ interrupt device */
210         IDETAPE_FLAG_DRQ_INTERRUPT      = (1 << 5),
211         /* 0 = no tape is loaded, so we don't rewind after ejecting */
212         IDETAPE_FLAG_MEDIUM_PRESENT     = (1 << 6),
213 };
214
215 /*
216  * Most of our global data which we need to save even as we leave the driver due
217  * to an interrupt or a timer event is stored in the struct defined below.
218  */
219 typedef struct ide_tape_obj {
220         ide_drive_t     *drive;
221         ide_driver_t    *driver;
222         struct gendisk  *disk;
223         struct kref     kref;
224
225         /*
226          *      Since a typical character device operation requires more
227          *      than one packet command, we provide here enough memory
228          *      for the maximum of interconnected packet commands.
229          *      The packet commands are stored in the circular array pc_stack.
230          *      pc_stack_index points to the last used entry, and warps around
231          *      to the start when we get to the last array entry.
232          *
233          *      pc points to the current processed packet command.
234          *
235          *      failed_pc points to the last failed packet command, or contains
236          *      NULL if we do not need to retry any packet command. This is
237          *      required since an additional packet command is needed before the
238          *      retry, to get detailed information on what went wrong.
239          */
240         /* Current packet command */
241         struct ide_atapi_pc *pc;
242         /* Last failed packet command */
243         struct ide_atapi_pc *failed_pc;
244         /* Packet command stack */
245         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
246         /* Next free packet command storage space */
247         int pc_stack_index;
248         struct request rq_stack[IDETAPE_PC_STACK];
249         /* We implement a circular array */
250         int rq_stack_index;
251
252         /*
253          * DSC polling variables.
254          *
255          * While polling for DSC we use postponed_rq to postpone the current
256          * request so that ide.c will be able to service pending requests on the
257          * other device. Note that at most we will have only one DSC (usually
258          * data transfer) request in the device request queue.
259          */
260         struct request *postponed_rq;
261         /* The time in which we started polling for DSC */
262         unsigned long dsc_polling_start;
263         /* Timer used to poll for dsc */
264         struct timer_list dsc_timer;
265         /* Read/Write dsc polling frequency */
266         unsigned long best_dsc_rw_freq;
267         unsigned long dsc_poll_freq;
268         unsigned long dsc_timeout;
269
270         /* Read position information */
271         u8 partition;
272         /* Current block */
273         unsigned int first_frame;
274
275         /* Last error information */
276         u8 sense_key, asc, ascq;
277
278         /* Character device operation */
279         unsigned int minor;
280         /* device name */
281         char name[4];
282         /* Current character device data transfer direction */
283         u8 chrdev_dir;
284
285         /* tape block size, usually 512 or 1024 bytes */
286         unsigned short blk_size;
287         int user_bs_factor;
288
289         /* Copy of the tape's Capabilities and Mechanical Page */
290         u8 caps[20];
291
292         /*
293          * Active data transfer request parameters.
294          *
295          * At most, there is only one ide-tape originated data transfer request
296          * in the device request queue. This allows ide.c to easily service
297          * requests from the other device when we postpone our active request.
298          */
299
300         /* Data buffer size chosen based on the tape's recommendation */
301         int buffer_size;
302         /* merge buffer */
303         struct idetape_bh *merge_bh;
304         /* size of the merge buffer */
305         int merge_bh_size;
306         /* pointer to current buffer head within the merge buffer */
307         struct idetape_bh *bh;
308         char *b_data;
309         int b_count;
310
311         int pages_per_buffer;
312         /* Wasted space in each stage */
313         int excess_bh_size;
314
315         /* Status/Action flags: long for set_bit */
316         unsigned long flags;
317         /* protects the ide-tape queue */
318         spinlock_t lock;
319
320         /* Measures average tape speed */
321         unsigned long avg_time;
322         int avg_size;
323         int avg_speed;
324
325         /* the door is currently locked */
326         int door_locked;
327         /* the tape hardware is write protected */
328         char drv_write_prot;
329         /* the tape is write protected (hardware or opened as read-only) */
330         char write_prot;
331
332         u32 debug_mask;
333 } idetape_tape_t;
334
335 static DEFINE_MUTEX(idetape_ref_mutex);
336
337 static struct class *idetape_sysfs_class;
338
339 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
340
341 #define ide_tape_g(disk) \
342         container_of((disk)->private_data, struct ide_tape_obj, driver)
343
344 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
345 {
346         struct ide_tape_obj *tape = NULL;
347
348         mutex_lock(&idetape_ref_mutex);
349         tape = ide_tape_g(disk);
350         if (tape)
351                 kref_get(&tape->kref);
352         mutex_unlock(&idetape_ref_mutex);
353         return tape;
354 }
355
356 static void ide_tape_release(struct kref *);
357
358 static void ide_tape_put(struct ide_tape_obj *tape)
359 {
360         mutex_lock(&idetape_ref_mutex);
361         kref_put(&tape->kref, ide_tape_release);
362         mutex_unlock(&idetape_ref_mutex);
363 }
364
365 /*
366  * The variables below are used for the character device interface. Additional
367  * state variables are defined in our ide_drive_t structure.
368  */
369 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
370
371 #define ide_tape_f(file) ((file)->private_data)
372
373 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
374 {
375         struct ide_tape_obj *tape = NULL;
376
377         mutex_lock(&idetape_ref_mutex);
378         tape = idetape_devs[i];
379         if (tape)
380                 kref_get(&tape->kref);
381         mutex_unlock(&idetape_ref_mutex);
382         return tape;
383 }
384
385 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
386                                   unsigned int bcount)
387 {
388         struct idetape_bh *bh = pc->bh;
389         int count;
390
391         while (bcount) {
392                 if (bh == NULL) {
393                         printk(KERN_ERR "ide-tape: bh == NULL in "
394                                 "idetape_input_buffers\n");
395                         ide_pad_transfer(drive, 0, bcount);
396                         return;
397                 }
398                 count = min(
399                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
400                         bcount);
401                 drive->hwif->input_data(drive, NULL, bh->b_data +
402                                         atomic_read(&bh->b_count), count);
403                 bcount -= count;
404                 atomic_add(count, &bh->b_count);
405                 if (atomic_read(&bh->b_count) == bh->b_size) {
406                         bh = bh->b_reqnext;
407                         if (bh)
408                                 atomic_set(&bh->b_count, 0);
409                 }
410         }
411         pc->bh = bh;
412 }
413
414 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
415                                    unsigned int bcount)
416 {
417         struct idetape_bh *bh = pc->bh;
418         int count;
419
420         while (bcount) {
421                 if (bh == NULL) {
422                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
423                                         __func__);
424                         return;
425                 }
426                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
427                 drive->hwif->output_data(drive, NULL, pc->b_data, count);
428                 bcount -= count;
429                 pc->b_data += count;
430                 pc->b_count -= count;
431                 if (!pc->b_count) {
432                         bh = bh->b_reqnext;
433                         pc->bh = bh;
434                         if (bh) {
435                                 pc->b_data = bh->b_data;
436                                 pc->b_count = atomic_read(&bh->b_count);
437                         }
438                 }
439         }
440 }
441
442 static void idetape_update_buffers(struct ide_atapi_pc *pc)
443 {
444         struct idetape_bh *bh = pc->bh;
445         int count;
446         unsigned int bcount = pc->xferred;
447
448         if (pc->flags & PC_FLAG_WRITING)
449                 return;
450         while (bcount) {
451                 if (bh == NULL) {
452                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
453                                         __func__);
454                         return;
455                 }
456                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
457                 atomic_set(&bh->b_count, count);
458                 if (atomic_read(&bh->b_count) == bh->b_size)
459                         bh = bh->b_reqnext;
460                 bcount -= count;
461         }
462         pc->bh = bh;
463 }
464
465 /*
466  *      idetape_next_pc_storage returns a pointer to a place in which we can
467  *      safely store a packet command, even though we intend to leave the
468  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
469  *      commands is allocated at initialization time.
470  */
471 static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
472 {
473         idetape_tape_t *tape = drive->driver_data;
474
475         debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
476
477         if (tape->pc_stack_index == IDETAPE_PC_STACK)
478                 tape->pc_stack_index = 0;
479         return (&tape->pc_stack[tape->pc_stack_index++]);
480 }
481
482 /*
483  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
484  *      Since we queue packet commands in the request queue, we need to
485  *      allocate a request, along with the allocation of a packet command.
486  */
487
488 /**************************************************************
489  *                                                            *
490  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
491  *  followed later on by kfree().   -ml                       *
492  *                                                            *
493  **************************************************************/
494
495 static struct request *idetape_next_rq_storage(ide_drive_t *drive)
496 {
497         idetape_tape_t *tape = drive->driver_data;
498
499         debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
500
501         if (tape->rq_stack_index == IDETAPE_PC_STACK)
502                 tape->rq_stack_index = 0;
503         return (&tape->rq_stack[tape->rq_stack_index++]);
504 }
505
506 /*
507  * called on each failed packet command retry to analyze the request sense. We
508  * currently do not utilize this information.
509  */
510 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
511 {
512         idetape_tape_t *tape = drive->driver_data;
513         struct ide_atapi_pc *pc = tape->failed_pc;
514
515         tape->sense_key = sense[2] & 0xF;
516         tape->asc       = sense[12];
517         tape->ascq      = sense[13];
518
519         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
520                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
521
522         /* Correct pc->xferred by asking the tape.       */
523         if (pc->flags & PC_FLAG_DMA_ERROR) {
524                 pc->xferred = pc->req_xfer -
525                         tape->blk_size *
526                         get_unaligned_be32(&sense[3]);
527                 idetape_update_buffers(pc);
528         }
529
530         /*
531          * If error was the result of a zero-length read or write command,
532          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
533          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
534          */
535         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
536             /* length == 0 */
537             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
538                 if (tape->sense_key == 5) {
539                         /* don't report an error, everything's ok */
540                         pc->error = 0;
541                         /* don't retry read/write */
542                         pc->flags |= PC_FLAG_ABORT;
543                 }
544         }
545         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
546                 pc->error = IDETAPE_ERROR_FILEMARK;
547                 pc->flags |= PC_FLAG_ABORT;
548         }
549         if (pc->c[0] == WRITE_6) {
550                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
551                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
552                         pc->error = IDETAPE_ERROR_EOD;
553                         pc->flags |= PC_FLAG_ABORT;
554                 }
555         }
556         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
557                 if (tape->sense_key == 8) {
558                         pc->error = IDETAPE_ERROR_EOD;
559                         pc->flags |= PC_FLAG_ABORT;
560                 }
561                 if (!(pc->flags & PC_FLAG_ABORT) &&
562                     pc->xferred)
563                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
564         }
565 }
566
567 /* Free data buffers completely. */
568 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
569 {
570         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
571
572         while (bh) {
573                 u32 size = bh->b_size;
574
575                 while (size) {
576                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
577
578                         if (bh->b_data)
579                                 free_pages((unsigned long)bh->b_data, order);
580
581                         size &= (order-1);
582                         bh->b_data += (1 << order) * PAGE_SIZE;
583                 }
584                 prev_bh = bh;
585                 bh = bh->b_reqnext;
586                 kfree(prev_bh);
587         }
588         kfree(tape->merge_bh);
589 }
590
591 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
592 {
593         struct request *rq = HWGROUP(drive)->rq;
594         idetape_tape_t *tape = drive->driver_data;
595         unsigned long flags;
596         int error;
597
598         debug_log(DBG_PROCS, "Enter %s\n", __func__);
599
600         switch (uptodate) {
601         case 0: error = IDETAPE_ERROR_GENERAL; break;
602         case 1: error = 0; break;
603         default: error = uptodate;
604         }
605         rq->errors = error;
606         if (error)
607                 tape->failed_pc = NULL;
608
609         if (!blk_special_request(rq)) {
610                 ide_end_request(drive, uptodate, nr_sects);
611                 return 0;
612         }
613
614         spin_lock_irqsave(&tape->lock, flags);
615
616         ide_end_drive_cmd(drive, 0, 0);
617
618         spin_unlock_irqrestore(&tape->lock, flags);
619         return 0;
620 }
621
622 static void ide_tape_callback(ide_drive_t *drive)
623 {
624         idetape_tape_t *tape = drive->driver_data;
625         struct ide_atapi_pc *pc = tape->pc;
626         int uptodate = pc->error ? 0 : 1;
627
628         debug_log(DBG_PROCS, "Enter %s\n", __func__);
629
630         if (pc->c[0] == REQUEST_SENSE) {
631                 if (uptodate)
632                         idetape_analyze_error(drive, pc->buf);
633                 else
634                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
635                                         "itself - Aborting request!\n");
636         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
637                 struct request *rq = drive->hwif->hwgroup->rq;
638                 int blocks = pc->xferred / tape->blk_size;
639
640                 tape->avg_size += blocks * tape->blk_size;
641
642                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
643                         tape->avg_speed = tape->avg_size * HZ /
644                                 (jiffies - tape->avg_time) / 1024;
645                         tape->avg_size = 0;
646                         tape->avg_time = jiffies;
647                 }
648
649                 tape->first_frame += blocks;
650                 rq->current_nr_sectors -= blocks;
651
652                 if (pc->error)
653                         uptodate = pc->error;
654         } else if (pc->c[0] == READ_POSITION && uptodate) {
655                 u8 *readpos = tape->pc->buf;
656
657                 debug_log(DBG_SENSE, "BOP - %s\n",
658                                 (readpos[0] & 0x80) ? "Yes" : "No");
659                 debug_log(DBG_SENSE, "EOP - %s\n",
660                                 (readpos[0] & 0x40) ? "Yes" : "No");
661
662                 if (readpos[0] & 0x4) {
663                         printk(KERN_INFO "ide-tape: Block location is unknown"
664                                          "to the tape\n");
665                         clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
666                         uptodate = 0;
667                 } else {
668                         debug_log(DBG_SENSE, "Block Location - %u\n",
669                                         be32_to_cpu(*(u32 *)&readpos[4]));
670
671                         tape->partition = readpos[1];
672                         tape->first_frame = be32_to_cpu(*(u32 *)&readpos[4]);
673                         set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
674                 }
675         }
676
677         idetape_end_request(drive, uptodate, 0);
678 }
679
680 static void idetape_init_pc(struct ide_atapi_pc *pc)
681 {
682         memset(pc->c, 0, 12);
683         pc->retries = 0;
684         pc->flags = 0;
685         pc->req_xfer = 0;
686         pc->buf = pc->pc_buf;
687         pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
688         pc->bh = NULL;
689         pc->b_data = NULL;
690         pc->callback = ide_tape_callback;
691 }
692
693 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
694 {
695         idetape_init_pc(pc);
696         pc->c[0] = REQUEST_SENSE;
697         pc->c[4] = 20;
698         pc->req_xfer = 20;
699 }
700
701 static void idetape_init_rq(struct request *rq, u8 cmd)
702 {
703         blk_rq_init(NULL, rq);
704         rq->cmd_type = REQ_TYPE_SPECIAL;
705         rq->cmd[0] = cmd;
706 }
707
708 /*
709  * Generate a new packet command request in front of the request queue, before
710  * the current request, so that it will be processed immediately, on the next
711  * pass through the driver. The function below is called from the request
712  * handling part of the driver (the "bottom" part). Safe storage for the request
713  * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
714  *
715  * Memory for those requests is pre-allocated at initialization time, and is
716  * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
717  * the maximum possible number of inter-dependent packet commands.
718  *
719  * The higher level of the driver - The ioctl handler and the character device
720  * handling functions should queue request to the lower level part and wait for
721  * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
722  */
723 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
724                                   struct request *rq)
725 {
726         struct ide_tape_obj *tape = drive->driver_data;
727
728         idetape_init_rq(rq, REQ_IDETAPE_PC1);
729         rq->cmd_flags |= REQ_PREEMPT;
730         rq->buffer = (char *) pc;
731         rq->rq_disk = tape->disk;
732         ide_do_drive_cmd(drive, rq);
733 }
734
735 /*
736  *      idetape_retry_pc is called when an error was detected during the
737  *      last packet command. We queue a request sense packet command in
738  *      the head of the request list.
739  */
740 static void idetape_retry_pc(ide_drive_t *drive)
741 {
742         idetape_tape_t *tape = drive->driver_data;
743         struct ide_atapi_pc *pc;
744         struct request *rq;
745
746         (void)ide_read_error(drive);
747         pc = idetape_next_pc_storage(drive);
748         rq = idetape_next_rq_storage(drive);
749         idetape_create_request_sense_cmd(pc);
750         set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
751         idetape_queue_pc_head(drive, pc, rq);
752 }
753
754 /*
755  * Postpone the current request so that ide.c will be able to service requests
756  * from another device on the same hwgroup while we are polling for DSC.
757  */
758 static void idetape_postpone_request(ide_drive_t *drive)
759 {
760         idetape_tape_t *tape = drive->driver_data;
761
762         debug_log(DBG_PROCS, "Enter %s\n", __func__);
763
764         tape->postponed_rq = HWGROUP(drive)->rq;
765         ide_stall_queue(drive, tape->dsc_poll_freq);
766 }
767
768 typedef void idetape_io_buf(ide_drive_t *, struct ide_atapi_pc *, unsigned int);
769
770 /*
771  * This is the usual interrupt handler which will be called during a packet
772  * command. We will transfer some of the data (as requested by the drive) and
773  * will re-point interrupt handler to us. When data transfer is finished, we
774  * will act according to the algorithm described before
775  * idetape_issue_pc.
776  */
777 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
778 {
779         ide_hwif_t *hwif = drive->hwif;
780         idetape_tape_t *tape = drive->driver_data;
781         struct ide_atapi_pc *pc = tape->pc;
782         xfer_func_t *xferfunc;
783         idetape_io_buf *iobuf;
784         unsigned int temp;
785         u16 bcount;
786         u8 stat, ireason;
787
788         debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
789
790         /* Clear the interrupt */
791         stat = ide_read_status(drive);
792
793         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
794                 if (hwif->dma_ops->dma_end(drive) || (stat & ERR_STAT)) {
795                         pc->flags |= PC_FLAG_DMA_ERROR;
796                 } else {
797                         pc->xferred = pc->req_xfer;
798                         idetape_update_buffers(pc);
799                 }
800                 debug_log(DBG_PROCS, "DMA finished\n");
801
802         }
803
804         /* No more interrupts */
805         if ((stat & DRQ_STAT) == 0) {
806                 debug_log(DBG_SENSE, "Packet command completed, %d bytes"
807                                 " transferred\n", pc->xferred);
808
809                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
810                 local_irq_enable_in_hardirq();
811
812                 if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
813                         stat &= ~ERR_STAT;
814                 if ((stat & ERR_STAT) || (pc->flags & PC_FLAG_DMA_ERROR)) {
815                         /* Error detected */
816                         debug_log(DBG_ERR, "%s: I/O error\n", tape->name);
817
818                         if (pc->c[0] == REQUEST_SENSE) {
819                                 printk(KERN_ERR "%s: I/O error in request sense"
820                                                 " command\n", drive->name);
821                                 return ide_do_reset(drive);
822                         }
823                         debug_log(DBG_ERR, "[cmd %x]: check condition\n",
824                                         pc->c[0]);
825
826                         /* Retry operation */
827                         idetape_retry_pc(drive);
828                         return ide_stopped;
829                 }
830                 pc->error = 0;
831                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
832                     (stat & SEEK_STAT) == 0) {
833                         /* Media access command */
834                         tape->dsc_polling_start = jiffies;
835                         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
836                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
837                         /* Allow ide.c to handle other requests */
838                         idetape_postpone_request(drive);
839                         return ide_stopped;
840                 }
841                 if (tape->failed_pc == pc)
842                         tape->failed_pc = NULL;
843                 /* Command finished - Call the callback function */
844                 pc->callback(drive);
845                 return ide_stopped;
846         }
847
848         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
849                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
850                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
851                                 "in DMA mode\n", drive->name);
852                 ide_dma_off(drive);
853                 return ide_do_reset(drive);
854         }
855         /* Get the number of bytes to transfer on this interrupt. */
856         bcount = (hwif->INB(hwif->io_ports.lbah_addr) << 8) |
857                   hwif->INB(hwif->io_ports.lbam_addr);
858
859         ireason = hwif->INB(hwif->io_ports.nsect_addr);
860
861         if (ireason & CD) {
862                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
863                 return ide_do_reset(drive);
864         }
865         if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
866                 /* Hopefully, we will never get here */
867                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
868                                 "to %s!\n", drive->name,
869                                 (ireason & IO) ? "Write" : "Read",
870                                 (ireason & IO) ? "Read" : "Write");
871                 return ide_do_reset(drive);
872         }
873         if (!(pc->flags & PC_FLAG_WRITING)) {
874                 /* Reading - Check that we have enough space */
875                 temp = pc->xferred + bcount;
876                 if (temp > pc->req_xfer) {
877                         if (temp > pc->buf_size) {
878                                 printk(KERN_ERR "%s: The device wants to send "
879                                                 "us more data than expected - "
880                                                 "discarding data\n",
881                                                 drive->name);
882                                 ide_pad_transfer(drive, 0, bcount);
883                                 ide_set_handler(drive, &idetape_pc_intr,
884                                                 IDETAPE_WAIT_CMD, NULL);
885                                 return ide_started;
886                         }
887                         debug_log(DBG_SENSE, "The device wants to send us more "
888                                 "data than expected - allowing transfer\n");
889                 }
890                 iobuf = &idetape_input_buffers;
891                 xferfunc = hwif->input_data;
892         } else {
893                 iobuf = &idetape_output_buffers;
894                 xferfunc = hwif->output_data;
895         }
896
897         if (pc->bh)
898                 iobuf(drive, pc, bcount);
899         else
900                 xferfunc(drive, NULL, pc->cur_pos, bcount);
901
902         /* Update the current position */
903         pc->xferred += bcount;
904         pc->cur_pos += bcount;
905
906         debug_log(DBG_SENSE, "[cmd %x] transferred %d bytes on that intr.\n",
907                         pc->c[0], bcount);
908
909         /* And set the interrupt handler again */
910         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
911         return ide_started;
912 }
913
914 /*
915  * Packet Command Interface
916  *
917  * The current Packet Command is available in tape->pc, and will not change
918  * until we finish handling it. Each packet command is associated with a
919  * callback function that will be called when the command is finished.
920  *
921  * The handling will be done in three stages:
922  *
923  * 1. idetape_issue_pc will send the packet command to the drive, and will set
924  * the interrupt handler to idetape_pc_intr.
925  *
926  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
927  * repeated until the device signals us that no more interrupts will be issued.
928  *
929  * 3. ATAPI Tape media access commands have immediate status with a delayed
930  * process. In case of a successful initiation of a media access packet command,
931  * the DSC bit will be set when the actual execution of the command is finished.
932  * Since the tape drive will not issue an interrupt, we have to poll for this
933  * event. In this case, we define the request as "low priority request" by
934  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
935  * exit the driver.
936  *
937  * ide.c will then give higher priority to requests which originate from the
938  * other device, until will change rq_status to RQ_ACTIVE.
939  *
940  * 4. When the packet command is finished, it will be checked for errors.
941  *
942  * 5. In case an error was found, we queue a request sense packet command in
943  * front of the request queue and retry the operation up to
944  * IDETAPE_MAX_PC_RETRIES times.
945  *
946  * 6. In case no error was found, or we decided to give up and not to retry
947  * again, the callback function will be called and then we will handle the next
948  * request.
949  */
950 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
951 {
952         ide_hwif_t *hwif = drive->hwif;
953         idetape_tape_t *tape = drive->driver_data;
954         struct ide_atapi_pc *pc = tape->pc;
955         int retries = 100;
956         ide_startstop_t startstop;
957         u8 ireason;
958
959         if (ide_wait_stat(&startstop, drive, DRQ_STAT, BUSY_STAT, WAIT_READY)) {
960                 printk(KERN_ERR "%s: Strange, packet command initiated yet "
961                                 "DRQ isn't asserted\n", drive->name);
962                 return startstop;
963         }
964         ireason = hwif->INB(hwif->io_ports.nsect_addr);
965         while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
966                 printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
967                                 "a packet command, retrying\n", drive->name);
968                 udelay(100);
969                 ireason = hwif->INB(hwif->io_ports.nsect_addr);
970                 if (retries == 0) {
971                         printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
972                                         "a packet command, ignoring\n",
973                                         drive->name);
974                         ireason |= CD;
975                         ireason &= ~IO;
976                 }
977         }
978         if ((ireason & CD) == 0 || (ireason & IO)) {
979                 printk(KERN_ERR "%s: (IO,CoD) != (0,1) while issuing "
980                                 "a packet command\n", drive->name);
981                 return ide_do_reset(drive);
982         }
983         /* Set the interrupt routine */
984         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
985
986         /* Begin DMA, if necessary */
987         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS)
988                 hwif->dma_ops->dma_start(drive);
989
990         /* Send the actual packet */
991         hwif->output_data(drive, NULL, pc->c, 12);
992
993         return ide_started;
994 }
995
996 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
997                 struct ide_atapi_pc *pc)
998 {
999         ide_hwif_t *hwif = drive->hwif;
1000         idetape_tape_t *tape = drive->driver_data;
1001         int dma_ok = 0;
1002         u16 bcount;
1003
1004         if (tape->pc->c[0] == REQUEST_SENSE &&
1005             pc->c[0] == REQUEST_SENSE) {
1006                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
1007                         "Two request sense in serial were issued\n");
1008         }
1009
1010         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
1011                 tape->failed_pc = pc;
1012         /* Set the current packet command */
1013         tape->pc = pc;
1014
1015         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
1016                 (pc->flags & PC_FLAG_ABORT)) {
1017                 /*
1018                  * We will "abort" retrying a packet command in case legitimate
1019                  * error code was received (crossing a filemark, or end of the
1020                  * media, for example).
1021                  */
1022                 if (!(pc->flags & PC_FLAG_ABORT)) {
1023                         if (!(pc->c[0] == TEST_UNIT_READY &&
1024                               tape->sense_key == 2 && tape->asc == 4 &&
1025                              (tape->ascq == 1 || tape->ascq == 8))) {
1026                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
1027                                                 "pc = %2x, key = %2x, "
1028                                                 "asc = %2x, ascq = %2x\n",
1029                                                 tape->name, pc->c[0],
1030                                                 tape->sense_key, tape->asc,
1031                                                 tape->ascq);
1032                         }
1033                         /* Giving up */
1034                         pc->error = IDETAPE_ERROR_GENERAL;
1035                 }
1036                 tape->failed_pc = NULL;
1037                 pc->callback(drive);
1038                 return ide_stopped;
1039         }
1040         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
1041
1042         pc->retries++;
1043         /* We haven't transferred any data yet */
1044         pc->xferred = 0;
1045         pc->cur_pos = pc->buf;
1046         /* Request to transfer the entire buffer at once */
1047         bcount = pc->req_xfer;
1048
1049         if (pc->flags & PC_FLAG_DMA_ERROR) {
1050                 pc->flags &= ~PC_FLAG_DMA_ERROR;
1051                 ide_dma_off(drive);
1052         }
1053         if ((pc->flags & PC_FLAG_DMA_RECOMMENDED) && drive->using_dma)
1054                 dma_ok = !hwif->dma_ops->dma_setup(drive);
1055
1056         ide_pktcmd_tf_load(drive, IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
1057
1058         if (dma_ok)
1059                 /* Will begin DMA later */
1060                 pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
1061         if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags)) {
1062                 ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
1063                                     IDETAPE_WAIT_CMD, NULL);
1064                 return ide_started;
1065         } else {
1066                 ide_execute_pkt_cmd(drive);
1067                 return idetape_transfer_pc(drive);
1068         }
1069 }
1070
1071 /* A mode sense command is used to "sense" tape parameters. */
1072 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
1073 {
1074         idetape_init_pc(pc);
1075         pc->c[0] = MODE_SENSE;
1076         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1077                 /* DBD = 1 - Don't return block descriptors */
1078                 pc->c[1] = 8;
1079         pc->c[2] = page_code;
1080         /*
1081          * Changed pc->c[3] to 0 (255 will at best return unused info).
1082          *
1083          * For SCSI this byte is defined as subpage instead of high byte
1084          * of length and some IDE drives seem to interpret it this way
1085          * and return an error when 255 is used.
1086          */
1087         pc->c[3] = 0;
1088         /* We will just discard data in that case */
1089         pc->c[4] = 255;
1090         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1091                 pc->req_xfer = 12;
1092         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
1093                 pc->req_xfer = 24;
1094         else
1095                 pc->req_xfer = 50;
1096 }
1097
1098 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
1099 {
1100         idetape_tape_t *tape = drive->driver_data;
1101         struct ide_atapi_pc *pc = tape->pc;
1102         u8 stat;
1103
1104         stat = ide_read_status(drive);
1105
1106         if (stat & SEEK_STAT) {
1107                 if (stat & ERR_STAT) {
1108                         /* Error detected */
1109                         if (pc->c[0] != TEST_UNIT_READY)
1110                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
1111                                                 tape->name);
1112                         /* Retry operation */
1113                         idetape_retry_pc(drive);
1114                         return ide_stopped;
1115                 }
1116                 pc->error = 0;
1117                 if (tape->failed_pc == pc)
1118                         tape->failed_pc = NULL;
1119         } else {
1120                 pc->error = IDETAPE_ERROR_GENERAL;
1121                 tape->failed_pc = NULL;
1122         }
1123         pc->callback(drive);
1124         return ide_stopped;
1125 }
1126
1127 static void idetape_create_read_cmd(idetape_tape_t *tape,
1128                 struct ide_atapi_pc *pc,
1129                 unsigned int length, struct idetape_bh *bh)
1130 {
1131         idetape_init_pc(pc);
1132         pc->c[0] = READ_6;
1133         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1134         pc->c[1] = 1;
1135         pc->bh = bh;
1136         atomic_set(&bh->b_count, 0);
1137         pc->buf = NULL;
1138         pc->buf_size = length * tape->blk_size;
1139         pc->req_xfer = pc->buf_size;
1140         if (pc->req_xfer == tape->buffer_size)
1141                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1142 }
1143
1144 static void idetape_create_write_cmd(idetape_tape_t *tape,
1145                 struct ide_atapi_pc *pc,
1146                 unsigned int length, struct idetape_bh *bh)
1147 {
1148         idetape_init_pc(pc);
1149         pc->c[0] = WRITE_6;
1150         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1151         pc->c[1] = 1;
1152         pc->flags |= PC_FLAG_WRITING;
1153         pc->bh = bh;
1154         pc->b_data = bh->b_data;
1155         pc->b_count = atomic_read(&bh->b_count);
1156         pc->buf = NULL;
1157         pc->buf_size = length * tape->blk_size;
1158         pc->req_xfer = pc->buf_size;
1159         if (pc->req_xfer == tape->buffer_size)
1160                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1161 }
1162
1163 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1164                                           struct request *rq, sector_t block)
1165 {
1166         idetape_tape_t *tape = drive->driver_data;
1167         struct ide_atapi_pc *pc = NULL;
1168         struct request *postponed_rq = tape->postponed_rq;
1169         u8 stat;
1170
1171         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
1172                         " current_nr_sectors: %d\n",
1173                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1174
1175         if (!blk_special_request(rq)) {
1176                 /* We do not support buffer cache originated requests. */
1177                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1178                         "request queue (%d)\n", drive->name, rq->cmd_type);
1179                 ide_end_request(drive, 0, 0);
1180                 return ide_stopped;
1181         }
1182
1183         /* Retry a failed packet command */
1184         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE)
1185                 return idetape_issue_pc(drive, tape->failed_pc);
1186
1187         if (postponed_rq != NULL)
1188                 if (rq != postponed_rq) {
1189                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1190                                         "Two DSC requests were queued\n");
1191                         idetape_end_request(drive, 0, 0);
1192                         return ide_stopped;
1193                 }
1194
1195         tape->postponed_rq = NULL;
1196
1197         /*
1198          * If the tape is still busy, postpone our request and service
1199          * the other device meanwhile.
1200          */
1201         stat = ide_read_status(drive);
1202
1203         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
1204                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1205
1206         if (drive->post_reset == 1) {
1207                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1208                 drive->post_reset = 0;
1209         }
1210
1211         if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&
1212             (stat & SEEK_STAT) == 0) {
1213                 if (postponed_rq == NULL) {
1214                         tape->dsc_polling_start = jiffies;
1215                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1216                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1217                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1218                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1219                                 tape->name);
1220                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1221                                 idetape_media_access_finished(drive);
1222                                 return ide_stopped;
1223                         } else {
1224                                 return ide_do_reset(drive);
1225                         }
1226                 } else if (time_after(jiffies,
1227                                         tape->dsc_polling_start +
1228                                         IDETAPE_DSC_MA_THRESHOLD))
1229                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1230                 idetape_postpone_request(drive);
1231                 return ide_stopped;
1232         }
1233         if (rq->cmd[0] & REQ_IDETAPE_READ) {
1234                 pc = idetape_next_pc_storage(drive);
1235                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
1236                                         (struct idetape_bh *)rq->special);
1237                 goto out;
1238         }
1239         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1240                 pc = idetape_next_pc_storage(drive);
1241                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
1242                                          (struct idetape_bh *)rq->special);
1243                 goto out;
1244         }
1245         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
1246                 pc = (struct ide_atapi_pc *) rq->buffer;
1247                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
1248                 rq->cmd[0] |= REQ_IDETAPE_PC2;
1249                 goto out;
1250         }
1251         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1252                 idetape_media_access_finished(drive);
1253                 return ide_stopped;
1254         }
1255         BUG();
1256 out:
1257         return idetape_issue_pc(drive, pc);
1258 }
1259
1260 /*
1261  * The function below uses __get_free_pages to allocate a data buffer of size
1262  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
1263  * much as possible.
1264  *
1265  * It returns a pointer to the newly allocated buffer, or NULL in case of
1266  * failure.
1267  */
1268 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
1269                                                   int full, int clear)
1270 {
1271         struct idetape_bh *prev_bh, *bh, *merge_bh;
1272         int pages = tape->pages_per_buffer;
1273         unsigned int order, b_allocd;
1274         char *b_data = NULL;
1275
1276         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1277         bh = merge_bh;
1278         if (bh == NULL)
1279                 goto abort;
1280
1281         order = fls(pages) - 1;
1282         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1283         if (!bh->b_data)
1284                 goto abort;
1285         b_allocd = (1 << order) * PAGE_SIZE;
1286         pages &= (order-1);
1287
1288         if (clear)
1289                 memset(bh->b_data, 0, b_allocd);
1290         bh->b_reqnext = NULL;
1291         bh->b_size = b_allocd;
1292         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1293
1294         while (pages) {
1295                 order = fls(pages) - 1;
1296                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
1297                 if (!b_data)
1298                         goto abort;
1299                 b_allocd = (1 << order) * PAGE_SIZE;
1300
1301                 if (clear)
1302                         memset(b_data, 0, b_allocd);
1303
1304                 /* newly allocated page frames below buffer header or ...*/
1305                 if (bh->b_data == b_data + b_allocd) {
1306                         bh->b_size += b_allocd;
1307                         bh->b_data -= b_allocd;
1308                         if (full)
1309                                 atomic_add(b_allocd, &bh->b_count);
1310                         continue;
1311                 }
1312                 /* they are above the header */
1313                 if (b_data == bh->b_data + bh->b_size) {
1314                         bh->b_size += b_allocd;
1315                         if (full)
1316                                 atomic_add(b_allocd, &bh->b_count);
1317                         continue;
1318                 }
1319                 prev_bh = bh;
1320                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1321                 if (!bh) {
1322                         free_pages((unsigned long) b_data, order);
1323                         goto abort;
1324                 }
1325                 bh->b_reqnext = NULL;
1326                 bh->b_data = b_data;
1327                 bh->b_size = b_allocd;
1328                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1329                 prev_bh->b_reqnext = bh;
1330
1331                 pages &= (order-1);
1332         }
1333
1334         bh->b_size -= tape->excess_bh_size;
1335         if (full)
1336                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1337         return merge_bh;
1338 abort:
1339         ide_tape_kfree_buffer(tape);
1340         return NULL;
1341 }
1342
1343 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1344                                         const char __user *buf, int n)
1345 {
1346         struct idetape_bh *bh = tape->bh;
1347         int count;
1348         int ret = 0;
1349
1350         while (n) {
1351                 if (bh == NULL) {
1352                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1353                                         __func__);
1354                         return 1;
1355                 }
1356                 count = min((unsigned int)
1357                                 (bh->b_size - atomic_read(&bh->b_count)),
1358                                 (unsigned int)n);
1359                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1360                                 count))
1361                         ret = 1;
1362                 n -= count;
1363                 atomic_add(count, &bh->b_count);
1364                 buf += count;
1365                 if (atomic_read(&bh->b_count) == bh->b_size) {
1366                         bh = bh->b_reqnext;
1367                         if (bh)
1368                                 atomic_set(&bh->b_count, 0);
1369                 }
1370         }
1371         tape->bh = bh;
1372         return ret;
1373 }
1374
1375 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1376                                       int n)
1377 {
1378         struct idetape_bh *bh = tape->bh;
1379         int count;
1380         int ret = 0;
1381
1382         while (n) {
1383                 if (bh == NULL) {
1384                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1385                                         __func__);
1386                         return 1;
1387                 }
1388                 count = min(tape->b_count, n);
1389                 if  (copy_to_user(buf, tape->b_data, count))
1390                         ret = 1;
1391                 n -= count;
1392                 tape->b_data += count;
1393                 tape->b_count -= count;
1394                 buf += count;
1395                 if (!tape->b_count) {
1396                         bh = bh->b_reqnext;
1397                         tape->bh = bh;
1398                         if (bh) {
1399                                 tape->b_data = bh->b_data;
1400                                 tape->b_count = atomic_read(&bh->b_count);
1401                         }
1402                 }
1403         }
1404         return ret;
1405 }
1406
1407 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1408 {
1409         struct idetape_bh *bh = tape->merge_bh;
1410         tape->bh = tape->merge_bh;
1411
1412         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1413                 atomic_set(&bh->b_count, 0);
1414         else {
1415                 tape->b_data = bh->b_data;
1416                 tape->b_count = atomic_read(&bh->b_count);
1417         }
1418 }
1419
1420 /*
1421  * Write a filemark if write_filemark=1. Flush the device buffers without
1422  * writing a filemark otherwise.
1423  */
1424 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1425                 struct ide_atapi_pc *pc, int write_filemark)
1426 {
1427         idetape_init_pc(pc);
1428         pc->c[0] = WRITE_FILEMARKS;
1429         pc->c[4] = write_filemark;
1430         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1431 }
1432
1433 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1434 {
1435         idetape_init_pc(pc);
1436         pc->c[0] = TEST_UNIT_READY;
1437 }
1438
1439 /*
1440  * We add a special packet command request to the tail of the request queue, and
1441  * wait for it to be serviced. This is not to be called from within the request
1442  * handling part of the driver! We allocate here data on the stack and it is
1443  * valid until the request is finished. This is not the case for the bottom part
1444  * of the driver, where we are always leaving the functions to wait for an
1445  * interrupt or a timer event.
1446  *
1447  * From the bottom part of the driver, we should allocate safe memory using
1448  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1449  * to the request list without waiting for it to be serviced! In that case, we
1450  * usually use idetape_queue_pc_head().
1451  */
1452 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1453 {
1454         struct ide_tape_obj *tape = drive->driver_data;
1455         struct request *rq;
1456         int error;
1457
1458         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1459         rq->cmd_type = REQ_TYPE_SPECIAL;
1460         rq->cmd[0] = REQ_IDETAPE_PC1;
1461         rq->buffer = (char *)pc;
1462         error = blk_execute_rq(drive->queue, tape->disk, rq, 0);
1463         blk_put_request(rq);
1464         return error;
1465 }
1466
1467 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1468                 struct ide_atapi_pc *pc, int cmd)
1469 {
1470         idetape_init_pc(pc);
1471         pc->c[0] = START_STOP;
1472         pc->c[4] = cmd;
1473         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1474 }
1475
1476 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1477 {
1478         idetape_tape_t *tape = drive->driver_data;
1479         struct ide_atapi_pc pc;
1480         int load_attempted = 0;
1481
1482         /* Wait for the tape to become ready */
1483         set_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
1484         timeout += jiffies;
1485         while (time_before(jiffies, timeout)) {
1486                 idetape_create_test_unit_ready_cmd(&pc);
1487                 if (!idetape_queue_pc_tail(drive, &pc))
1488                         return 0;
1489                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1490                     || (tape->asc == 0x3A)) {
1491                         /* no media */
1492                         if (load_attempted)
1493                                 return -ENOMEDIUM;
1494                         idetape_create_load_unload_cmd(drive, &pc,
1495                                                         IDETAPE_LU_LOAD_MASK);
1496                         idetape_queue_pc_tail(drive, &pc);
1497                         load_attempted = 1;
1498                 /* not about to be ready */
1499                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1500                              (tape->ascq == 1 || tape->ascq == 8)))
1501                         return -EIO;
1502                 msleep(100);
1503         }
1504         return -EIO;
1505 }
1506
1507 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1508 {
1509         struct ide_atapi_pc pc;
1510         int rc;
1511
1512         idetape_create_write_filemark_cmd(drive, &pc, 0);
1513         rc = idetape_queue_pc_tail(drive, &pc);
1514         if (rc)
1515                 return rc;
1516         idetape_wait_ready(drive, 60 * 5 * HZ);
1517         return 0;
1518 }
1519
1520 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1521 {
1522         idetape_init_pc(pc);
1523         pc->c[0] = READ_POSITION;
1524         pc->req_xfer = 20;
1525 }
1526
1527 static int idetape_read_position(ide_drive_t *drive)
1528 {
1529         idetape_tape_t *tape = drive->driver_data;
1530         struct ide_atapi_pc pc;
1531         int position;
1532
1533         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1534
1535         idetape_create_read_position_cmd(&pc);
1536         if (idetape_queue_pc_tail(drive, &pc))
1537                 return -1;
1538         position = tape->first_frame;
1539         return position;
1540 }
1541
1542 static void idetape_create_locate_cmd(ide_drive_t *drive,
1543                 struct ide_atapi_pc *pc,
1544                 unsigned int block, u8 partition, int skip)
1545 {
1546         idetape_init_pc(pc);
1547         pc->c[0] = POSITION_TO_ELEMENT;
1548         pc->c[1] = 2;
1549         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1550         pc->c[8] = partition;
1551         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1552 }
1553
1554 static int idetape_create_prevent_cmd(ide_drive_t *drive,
1555                 struct ide_atapi_pc *pc, int prevent)
1556 {
1557         idetape_tape_t *tape = drive->driver_data;
1558
1559         /* device supports locking according to capabilities page */
1560         if (!(tape->caps[6] & 0x01))
1561                 return 0;
1562
1563         idetape_init_pc(pc);
1564         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
1565         pc->c[4] = prevent;
1566         return 1;
1567 }
1568
1569 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1570 {
1571         idetape_tape_t *tape = drive->driver_data;
1572
1573         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1574                 return;
1575
1576         clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
1577         tape->merge_bh_size = 0;
1578         if (tape->merge_bh != NULL) {
1579                 ide_tape_kfree_buffer(tape);
1580                 tape->merge_bh = NULL;
1581         }
1582
1583         tape->chrdev_dir = IDETAPE_DIR_NONE;
1584 }
1585
1586 /*
1587  * Position the tape to the requested block using the LOCATE packet command.
1588  * A READ POSITION command is then issued to check where we are positioned. Like
1589  * all higher level operations, we queue the commands at the tail of the request
1590  * queue and wait for their completion.
1591  */
1592 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1593                 u8 partition, int skip)
1594 {
1595         idetape_tape_t *tape = drive->driver_data;
1596         int retval;
1597         struct ide_atapi_pc pc;
1598
1599         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1600                 __ide_tape_discard_merge_buffer(drive);
1601         idetape_wait_ready(drive, 60 * 5 * HZ);
1602         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1603         retval = idetape_queue_pc_tail(drive, &pc);
1604         if (retval)
1605                 return (retval);
1606
1607         idetape_create_read_position_cmd(&pc);
1608         return (idetape_queue_pc_tail(drive, &pc));
1609 }
1610
1611 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1612                                           int restore_position)
1613 {
1614         idetape_tape_t *tape = drive->driver_data;
1615         int seek, position;
1616
1617         __ide_tape_discard_merge_buffer(drive);
1618         if (restore_position) {
1619                 position = idetape_read_position(drive);
1620                 seek = position > 0 ? position : 0;
1621                 if (idetape_position_tape(drive, seek, 0, 0)) {
1622                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1623                                          " %s\n", tape->name, __func__);
1624                         return;
1625                 }
1626         }
1627 }
1628
1629 /*
1630  * Generate a read/write request for the block device interface and wait for it
1631  * to be serviced.
1632  */
1633 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1634                                  struct idetape_bh *bh)
1635 {
1636         idetape_tape_t *tape = drive->driver_data;
1637         struct request *rq;
1638         int ret, errors;
1639
1640         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1641
1642         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1643         rq->cmd_type = REQ_TYPE_SPECIAL;
1644         rq->cmd[0] = cmd;
1645         rq->rq_disk = tape->disk;
1646         rq->special = (void *)bh;
1647         rq->sector = tape->first_frame;
1648         rq->nr_sectors = blocks;
1649         rq->current_nr_sectors = blocks;
1650         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1651
1652         errors = rq->errors;
1653         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1654         blk_put_request(rq);
1655
1656         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1657                 return 0;
1658
1659         if (tape->merge_bh)
1660                 idetape_init_merge_buffer(tape);
1661         if (errors == IDETAPE_ERROR_GENERAL)
1662                 return -EIO;
1663         return ret;
1664 }
1665
1666 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1667 {
1668         idetape_init_pc(pc);
1669         pc->c[0] = INQUIRY;
1670         pc->c[4] = 254;
1671         pc->req_xfer = 254;
1672 }
1673
1674 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1675                 struct ide_atapi_pc *pc)
1676 {
1677         idetape_init_pc(pc);
1678         pc->c[0] = REZERO_UNIT;
1679         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1680 }
1681
1682 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1683 {
1684         idetape_init_pc(pc);
1685         pc->c[0] = ERASE;
1686         pc->c[1] = 1;
1687         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1688 }
1689
1690 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1691 {
1692         idetape_init_pc(pc);
1693         pc->c[0] = SPACE;
1694         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1695         pc->c[1] = cmd;
1696         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1697 }
1698
1699 /* Queue up a character device originated write request. */
1700 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1701 {
1702         idetape_tape_t *tape = drive->driver_data;
1703
1704         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1705
1706         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1707                                      blocks, tape->merge_bh);
1708 }
1709
1710 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1711 {
1712         idetape_tape_t *tape = drive->driver_data;
1713         int blocks, min;
1714         struct idetape_bh *bh;
1715
1716         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1717                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1718                                 " but we are not writing.\n");
1719                 return;
1720         }
1721         if (tape->merge_bh_size > tape->buffer_size) {
1722                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1723                 tape->merge_bh_size = tape->buffer_size;
1724         }
1725         if (tape->merge_bh_size) {
1726                 blocks = tape->merge_bh_size / tape->blk_size;
1727                 if (tape->merge_bh_size % tape->blk_size) {
1728                         unsigned int i;
1729
1730                         blocks++;
1731                         i = tape->blk_size - tape->merge_bh_size %
1732                                 tape->blk_size;
1733                         bh = tape->bh->b_reqnext;
1734                         while (bh) {
1735                                 atomic_set(&bh->b_count, 0);
1736                                 bh = bh->b_reqnext;
1737                         }
1738                         bh = tape->bh;
1739                         while (i) {
1740                                 if (bh == NULL) {
1741                                         printk(KERN_INFO "ide-tape: bug,"
1742                                                          " bh NULL\n");
1743                                         break;
1744                                 }
1745                                 min = min(i, (unsigned int)(bh->b_size -
1746                                                 atomic_read(&bh->b_count)));
1747                                 memset(bh->b_data + atomic_read(&bh->b_count),
1748                                                 0, min);
1749                                 atomic_add(min, &bh->b_count);
1750                                 i -= min;
1751                                 bh = bh->b_reqnext;
1752                         }
1753                 }
1754                 (void) idetape_add_chrdev_write_request(drive, blocks);
1755                 tape->merge_bh_size = 0;
1756         }
1757         if (tape->merge_bh != NULL) {
1758                 ide_tape_kfree_buffer(tape);
1759                 tape->merge_bh = NULL;
1760         }
1761         tape->chrdev_dir = IDETAPE_DIR_NONE;
1762 }
1763
1764 static int idetape_init_read(ide_drive_t *drive)
1765 {
1766         idetape_tape_t *tape = drive->driver_data;
1767         int bytes_read;
1768
1769         /* Initialize read operation */
1770         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1771                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1772                         ide_tape_flush_merge_buffer(drive);
1773                         idetape_flush_tape_buffers(drive);
1774                 }
1775                 if (tape->merge_bh || tape->merge_bh_size) {
1776                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1777                                          " 0 now\n");
1778                         tape->merge_bh_size = 0;
1779                 }
1780                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1781                 if (!tape->merge_bh)
1782                         return -ENOMEM;
1783                 tape->chrdev_dir = IDETAPE_DIR_READ;
1784
1785                 /*
1786                  * Issue a read 0 command to ensure that DSC handshake is
1787                  * switched from completion mode to buffer available mode.
1788                  * No point in issuing this if DSC overlap isn't supported, some
1789                  * drives (Seagate STT3401A) will return an error.
1790                  */
1791                 if (drive->dsc_overlap) {
1792                         bytes_read = idetape_queue_rw_tail(drive,
1793                                                         REQ_IDETAPE_READ, 0,
1794                                                         tape->merge_bh);
1795                         if (bytes_read < 0) {
1796                                 ide_tape_kfree_buffer(tape);
1797                                 tape->merge_bh = NULL;
1798                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1799                                 return bytes_read;
1800                         }
1801                 }
1802         }
1803
1804         return 0;
1805 }
1806
1807 /* called from idetape_chrdev_read() to service a chrdev read request. */
1808 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1809 {
1810         idetape_tape_t *tape = drive->driver_data;
1811
1812         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1813
1814         /* If we are at a filemark, return a read length of 0 */
1815         if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1816                 return 0;
1817
1818         idetape_init_read(drive);
1819
1820         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1821                                      tape->merge_bh);
1822 }
1823
1824 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1825 {
1826         idetape_tape_t *tape = drive->driver_data;
1827         struct idetape_bh *bh;
1828         int blocks;
1829
1830         while (bcount) {
1831                 unsigned int count;
1832
1833                 bh = tape->merge_bh;
1834                 count = min(tape->buffer_size, bcount);
1835                 bcount -= count;
1836                 blocks = count / tape->blk_size;
1837                 while (count) {
1838                         atomic_set(&bh->b_count,
1839                                    min(count, (unsigned int)bh->b_size));
1840                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1841                         count -= atomic_read(&bh->b_count);
1842                         bh = bh->b_reqnext;
1843                 }
1844                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1845                                       tape->merge_bh);
1846         }
1847 }
1848
1849 /*
1850  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1851  * currently support only one partition.
1852  */
1853 static int idetape_rewind_tape(ide_drive_t *drive)
1854 {
1855         int retval;
1856         struct ide_atapi_pc pc;
1857         idetape_tape_t *tape;
1858         tape = drive->driver_data;
1859
1860         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1861
1862         idetape_create_rewind_cmd(drive, &pc);
1863         retval = idetape_queue_pc_tail(drive, &pc);
1864         if (retval)
1865                 return retval;
1866
1867         idetape_create_read_position_cmd(&pc);
1868         retval = idetape_queue_pc_tail(drive, &pc);
1869         if (retval)
1870                 return retval;
1871         return 0;
1872 }
1873
1874 /* mtio.h compatible commands should be issued to the chrdev interface. */
1875 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1876                                 unsigned long arg)
1877 {
1878         idetape_tape_t *tape = drive->driver_data;
1879         void __user *argp = (void __user *)arg;
1880
1881         struct idetape_config {
1882                 int dsc_rw_frequency;
1883                 int dsc_media_access_frequency;
1884                 int nr_stages;
1885         } config;
1886
1887         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1888
1889         switch (cmd) {
1890         case 0x0340:
1891                 if (copy_from_user(&config, argp, sizeof(config)))
1892                         return -EFAULT;
1893                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1894                 break;
1895         case 0x0350:
1896                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1897                 config.nr_stages = 1;
1898                 if (copy_to_user(argp, &config, sizeof(config)))
1899                         return -EFAULT;
1900                 break;
1901         default:
1902                 return -EIO;
1903         }
1904         return 0;
1905 }
1906
1907 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1908                                         int mt_count)
1909 {
1910         idetape_tape_t *tape = drive->driver_data;
1911         struct ide_atapi_pc pc;
1912         int retval, count = 0;
1913         int sprev = !!(tape->caps[4] & 0x20);
1914
1915         if (mt_count == 0)
1916                 return 0;
1917         if (MTBSF == mt_op || MTBSFM == mt_op) {
1918                 if (!sprev)
1919                         return -EIO;
1920                 mt_count = -mt_count;
1921         }
1922
1923         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1924                 tape->merge_bh_size = 0;
1925                 if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
1926                         ++count;
1927                 ide_tape_discard_merge_buffer(drive, 0);
1928         }
1929
1930         switch (mt_op) {
1931         case MTFSF:
1932         case MTBSF:
1933                 idetape_create_space_cmd(&pc, mt_count - count,
1934                                          IDETAPE_SPACE_OVER_FILEMARK);
1935                 return idetape_queue_pc_tail(drive, &pc);
1936         case MTFSFM:
1937         case MTBSFM:
1938                 if (!sprev)
1939                         return -EIO;
1940                 retval = idetape_space_over_filemarks(drive, MTFSF,
1941                                                       mt_count - count);
1942                 if (retval)
1943                         return retval;
1944                 count = (MTBSFM == mt_op ? 1 : -1);
1945                 return idetape_space_over_filemarks(drive, MTFSF, count);
1946         default:
1947                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1948                                 mt_op);
1949                 return -EIO;
1950         }
1951 }
1952
1953 /*
1954  * Our character device read / write functions.
1955  *
1956  * The tape is optimized to maximize throughput when it is transferring an
1957  * integral number of the "continuous transfer limit", which is a parameter of
1958  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1959  *
1960  * As of version 1.3 of the driver, the character device provides an abstract
1961  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1962  * same backup/restore procedure is supported. The driver will internally
1963  * convert the requests to the recommended transfer unit, so that an unmatch
1964  * between the user's block size to the recommended size will only result in a
1965  * (slightly) increased driver overhead, but will no longer hit performance.
1966  * This is not applicable to Onstream.
1967  */
1968 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1969                                    size_t count, loff_t *ppos)
1970 {
1971         struct ide_tape_obj *tape = ide_tape_f(file);
1972         ide_drive_t *drive = tape->drive;
1973         ssize_t bytes_read, temp, actually_read = 0, rc;
1974         ssize_t ret = 0;
1975         u16 ctl = *(u16 *)&tape->caps[12];
1976
1977         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1978
1979         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1980                 if (test_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags))
1981                         if (count > tape->blk_size &&
1982                             (count % tape->blk_size) == 0)
1983                                 tape->user_bs_factor = count / tape->blk_size;
1984         }
1985         rc = idetape_init_read(drive);
1986         if (rc < 0)
1987                 return rc;
1988         if (count == 0)
1989                 return (0);
1990         if (tape->merge_bh_size) {
1991                 actually_read = min((unsigned int)(tape->merge_bh_size),
1992                                     (unsigned int)count);
1993                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1994                         ret = -EFAULT;
1995                 buf += actually_read;
1996                 tape->merge_bh_size -= actually_read;
1997                 count -= actually_read;
1998         }
1999         while (count >= tape->buffer_size) {
2000                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2001                 if (bytes_read <= 0)
2002                         goto finish;
2003                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
2004                         ret = -EFAULT;
2005                 buf += bytes_read;
2006                 count -= bytes_read;
2007                 actually_read += bytes_read;
2008         }
2009         if (count) {
2010                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2011                 if (bytes_read <= 0)
2012                         goto finish;
2013                 temp = min((unsigned long)count, (unsigned long)bytes_read);
2014                 if (idetape_copy_stage_to_user(tape, buf, temp))
2015                         ret = -EFAULT;
2016                 actually_read += temp;
2017                 tape->merge_bh_size = bytes_read-temp;
2018         }
2019 finish:
2020         if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
2021                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
2022
2023                 idetape_space_over_filemarks(drive, MTFSF, 1);
2024                 return 0;
2025         }
2026
2027         return ret ? ret : actually_read;
2028 }
2029
2030 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
2031                                      size_t count, loff_t *ppos)
2032 {
2033         struct ide_tape_obj *tape = ide_tape_f(file);
2034         ide_drive_t *drive = tape->drive;
2035         ssize_t actually_written = 0;
2036         ssize_t ret = 0;
2037         u16 ctl = *(u16 *)&tape->caps[12];
2038
2039         /* The drive is write protected. */
2040         if (tape->write_prot)
2041                 return -EACCES;
2042
2043         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2044
2045         /* Initialize write operation */
2046         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2047                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2048                         ide_tape_discard_merge_buffer(drive, 1);
2049                 if (tape->merge_bh || tape->merge_bh_size) {
2050                         printk(KERN_ERR "ide-tape: merge_bh_size "
2051                                 "should be 0 now\n");
2052                         tape->merge_bh_size = 0;
2053                 }
2054                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
2055                 if (!tape->merge_bh)
2056                         return -ENOMEM;
2057                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
2058                 idetape_init_merge_buffer(tape);
2059
2060                 /*
2061                  * Issue a write 0 command to ensure that DSC handshake is
2062                  * switched from completion mode to buffer available mode. No
2063                  * point in issuing this if DSC overlap isn't supported, some
2064                  * drives (Seagate STT3401A) will return an error.
2065                  */
2066                 if (drive->dsc_overlap) {
2067                         ssize_t retval = idetape_queue_rw_tail(drive,
2068                                                         REQ_IDETAPE_WRITE, 0,
2069                                                         tape->merge_bh);
2070                         if (retval < 0) {
2071                                 ide_tape_kfree_buffer(tape);
2072                                 tape->merge_bh = NULL;
2073                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2074                                 return retval;
2075                         }
2076                 }
2077         }
2078         if (count == 0)
2079                 return (0);
2080         if (tape->merge_bh_size) {
2081                 if (tape->merge_bh_size >= tape->buffer_size) {
2082                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
2083                         tape->merge_bh_size = 0;
2084                 }
2085                 actually_written = min((unsigned int)
2086                                 (tape->buffer_size - tape->merge_bh_size),
2087                                 (unsigned int)count);
2088                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
2089                                 ret = -EFAULT;
2090                 buf += actually_written;
2091                 tape->merge_bh_size += actually_written;
2092                 count -= actually_written;
2093
2094                 if (tape->merge_bh_size == tape->buffer_size) {
2095                         ssize_t retval;
2096                         tape->merge_bh_size = 0;
2097                         retval = idetape_add_chrdev_write_request(drive, ctl);
2098                         if (retval <= 0)
2099                                 return (retval);
2100                 }
2101         }
2102         while (count >= tape->buffer_size) {
2103                 ssize_t retval;
2104                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
2105                         ret = -EFAULT;
2106                 buf += tape->buffer_size;
2107                 count -= tape->buffer_size;
2108                 retval = idetape_add_chrdev_write_request(drive, ctl);
2109                 actually_written += tape->buffer_size;
2110                 if (retval <= 0)
2111                         return (retval);
2112         }
2113         if (count) {
2114                 actually_written += count;
2115                 if (idetape_copy_stage_from_user(tape, buf, count))
2116                         ret = -EFAULT;
2117                 tape->merge_bh_size += count;
2118         }
2119         return ret ? ret : actually_written;
2120 }
2121
2122 static int idetape_write_filemark(ide_drive_t *drive)
2123 {
2124         struct ide_atapi_pc pc;
2125
2126         /* Write a filemark */
2127         idetape_create_write_filemark_cmd(drive, &pc, 1);
2128         if (idetape_queue_pc_tail(drive, &pc)) {
2129                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
2130                 return -EIO;
2131         }
2132         return 0;
2133 }
2134
2135 /*
2136  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
2137  * requested.
2138  *
2139  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
2140  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
2141  * usually not supported.
2142  *
2143  * The following commands are currently not supported:
2144  *
2145  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
2146  * MT_ST_WRITE_THRESHOLD.
2147  */
2148 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
2149 {
2150         idetape_tape_t *tape = drive->driver_data;
2151         struct ide_atapi_pc pc;
2152         int i, retval;
2153
2154         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
2155                         mt_op, mt_count);
2156
2157         switch (mt_op) {
2158         case MTFSF:
2159         case MTFSFM:
2160         case MTBSF:
2161         case MTBSFM:
2162                 if (!mt_count)
2163                         return 0;
2164                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
2165         default:
2166                 break;
2167         }
2168
2169         switch (mt_op) {
2170         case MTWEOF:
2171                 if (tape->write_prot)
2172                         return -EACCES;
2173                 ide_tape_discard_merge_buffer(drive, 1);
2174                 for (i = 0; i < mt_count; i++) {
2175                         retval = idetape_write_filemark(drive);
2176                         if (retval)
2177                                 return retval;
2178                 }
2179                 return 0;
2180         case MTREW:
2181                 ide_tape_discard_merge_buffer(drive, 0);
2182                 if (idetape_rewind_tape(drive))
2183                         return -EIO;
2184                 return 0;
2185         case MTLOAD:
2186                 ide_tape_discard_merge_buffer(drive, 0);
2187                 idetape_create_load_unload_cmd(drive, &pc,
2188                                                IDETAPE_LU_LOAD_MASK);
2189                 return idetape_queue_pc_tail(drive, &pc);
2190         case MTUNLOAD:
2191         case MTOFFL:
2192                 /*
2193                  * If door is locked, attempt to unlock before
2194                  * attempting to eject.
2195                  */
2196                 if (tape->door_locked) {
2197                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2198                                 if (!idetape_queue_pc_tail(drive, &pc))
2199                                         tape->door_locked = DOOR_UNLOCKED;
2200                 }
2201                 ide_tape_discard_merge_buffer(drive, 0);
2202                 idetape_create_load_unload_cmd(drive, &pc,
2203                                               !IDETAPE_LU_LOAD_MASK);
2204                 retval = idetape_queue_pc_tail(drive, &pc);
2205                 if (!retval)
2206                         clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
2207                 return retval;
2208         case MTNOP:
2209                 ide_tape_discard_merge_buffer(drive, 0);
2210                 return idetape_flush_tape_buffers(drive);
2211         case MTRETEN:
2212                 ide_tape_discard_merge_buffer(drive, 0);
2213                 idetape_create_load_unload_cmd(drive, &pc,
2214                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2215                 return idetape_queue_pc_tail(drive, &pc);
2216         case MTEOM:
2217                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
2218                 return idetape_queue_pc_tail(drive, &pc);
2219         case MTERASE:
2220                 (void)idetape_rewind_tape(drive);
2221                 idetape_create_erase_cmd(&pc);
2222                 return idetape_queue_pc_tail(drive, &pc);
2223         case MTSETBLK:
2224                 if (mt_count) {
2225                         if (mt_count < tape->blk_size ||
2226                             mt_count % tape->blk_size)
2227                                 return -EIO;
2228                         tape->user_bs_factor = mt_count / tape->blk_size;
2229                         clear_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2230                 } else
2231                         set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
2232                 return 0;
2233         case MTSEEK:
2234                 ide_tape_discard_merge_buffer(drive, 0);
2235                 return idetape_position_tape(drive,
2236                         mt_count * tape->user_bs_factor, tape->partition, 0);
2237         case MTSETPART:
2238                 ide_tape_discard_merge_buffer(drive, 0);
2239                 return idetape_position_tape(drive, 0, mt_count, 0);
2240         case MTFSR:
2241         case MTBSR:
2242         case MTLOCK:
2243                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
2244                         return 0;
2245                 retval = idetape_queue_pc_tail(drive, &pc);
2246                 if (retval)
2247                         return retval;
2248                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
2249                 return 0;
2250         case MTUNLOCK:
2251                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
2252                         return 0;
2253                 retval = idetape_queue_pc_tail(drive, &pc);
2254                 if (retval)
2255                         return retval;
2256                 tape->door_locked = DOOR_UNLOCKED;
2257                 return 0;
2258         default:
2259                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2260                                 mt_op);
2261                 return -EIO;
2262         }
2263 }
2264
2265 /*
2266  * Our character device ioctls. General mtio.h magnetic io commands are
2267  * supported here, and not in the corresponding block interface. Our own
2268  * ide-tape ioctls are supported on both interfaces.
2269  */
2270 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
2271                                 unsigned int cmd, unsigned long arg)
2272 {
2273         struct ide_tape_obj *tape = ide_tape_f(file);
2274         ide_drive_t *drive = tape->drive;
2275         struct mtop mtop;
2276         struct mtget mtget;
2277         struct mtpos mtpos;
2278         int block_offset = 0, position = tape->first_frame;
2279         void __user *argp = (void __user *)arg;
2280
2281         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
2282
2283         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2284                 ide_tape_flush_merge_buffer(drive);
2285                 idetape_flush_tape_buffers(drive);
2286         }
2287         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
2288                 block_offset = tape->merge_bh_size /
2289                         (tape->blk_size * tape->user_bs_factor);
2290                 position = idetape_read_position(drive);
2291                 if (position < 0)
2292                         return -EIO;
2293         }
2294         switch (cmd) {
2295         case MTIOCTOP:
2296                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
2297                         return -EFAULT;
2298                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
2299         case MTIOCGET:
2300                 memset(&mtget, 0, sizeof(struct mtget));
2301                 mtget.mt_type = MT_ISSCSI2;
2302                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
2303                 mtget.mt_dsreg =
2304                         ((tape->blk_size * tape->user_bs_factor)
2305                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
2306
2307                 if (tape->drv_write_prot)
2308                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
2309
2310                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
2311                         return -EFAULT;
2312                 return 0;
2313         case MTIOCPOS:
2314                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
2315                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
2316                         return -EFAULT;
2317                 return 0;
2318         default:
2319                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2320                         ide_tape_discard_merge_buffer(drive, 1);
2321                 return idetape_blkdev_ioctl(drive, cmd, arg);
2322         }
2323 }
2324
2325 /*
2326  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
2327  * block size with the reported value.
2328  */
2329 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
2330 {
2331         idetape_tape_t *tape = drive->driver_data;
2332         struct ide_atapi_pc pc;
2333
2334         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
2335         if (idetape_queue_pc_tail(drive, &pc)) {
2336                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
2337                 if (tape->blk_size == 0) {
2338                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
2339                                             "block size, assuming 32k\n");
2340                         tape->blk_size = 32768;
2341                 }
2342                 return;
2343         }
2344         tape->blk_size = (pc.buf[4 + 5] << 16) +
2345                                 (pc.buf[4 + 6] << 8)  +
2346                                  pc.buf[4 + 7];
2347         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
2348 }
2349
2350 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
2351 {
2352         unsigned int minor = iminor(inode), i = minor & ~0xc0;
2353         ide_drive_t *drive;
2354         idetape_tape_t *tape;
2355         struct ide_atapi_pc pc;
2356         int retval;
2357
2358         if (i >= MAX_HWIFS * MAX_DRIVES)
2359                 return -ENXIO;
2360
2361         tape = ide_tape_chrdev_get(i);
2362         if (!tape)
2363                 return -ENXIO;
2364
2365         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2366
2367         /*
2368          * We really want to do nonseekable_open(inode, filp); here, but some
2369          * versions of tar incorrectly call lseek on tapes and bail out if that
2370          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
2371          */
2372         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
2373
2374         drive = tape->drive;
2375
2376         filp->private_data = tape;
2377
2378         if (test_and_set_bit(IDETAPE_FLAG_BUSY, &tape->flags)) {
2379                 retval = -EBUSY;
2380                 goto out_put_tape;
2381         }
2382
2383         retval = idetape_wait_ready(drive, 60 * HZ);
2384         if (retval) {
2385                 clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2386                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
2387                 goto out_put_tape;
2388         }
2389
2390         idetape_read_position(drive);
2391         if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
2392                 (void)idetape_rewind_tape(drive);
2393
2394         /* Read block size and write protect status from drive. */
2395         ide_tape_get_bsize_from_bdesc(drive);
2396
2397         /* Set write protect flag if device is opened as read-only. */
2398         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
2399                 tape->write_prot = 1;
2400         else
2401                 tape->write_prot = tape->drv_write_prot;
2402
2403         /* Make sure drive isn't write protected if user wants to write. */
2404         if (tape->write_prot) {
2405                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
2406                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
2407                         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2408                         retval = -EROFS;
2409                         goto out_put_tape;
2410                 }
2411         }
2412
2413         /* Lock the tape drive door so user can't eject. */
2414         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2415                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
2416                         if (!idetape_queue_pc_tail(drive, &pc)) {
2417                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2418                                         tape->door_locked = DOOR_LOCKED;
2419                         }
2420                 }
2421         }
2422         return 0;
2423
2424 out_put_tape:
2425         ide_tape_put(tape);
2426         return retval;
2427 }
2428
2429 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2430 {
2431         idetape_tape_t *tape = drive->driver_data;
2432
2433         ide_tape_flush_merge_buffer(drive);
2434         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2435         if (tape->merge_bh != NULL) {
2436                 idetape_pad_zeros(drive, tape->blk_size *
2437                                 (tape->user_bs_factor - 1));
2438                 ide_tape_kfree_buffer(tape);
2439                 tape->merge_bh = NULL;
2440         }
2441         idetape_write_filemark(drive);
2442         idetape_flush_tape_buffers(drive);
2443         idetape_flush_tape_buffers(drive);
2444 }
2445
2446 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2447 {
2448         struct ide_tape_obj *tape = ide_tape_f(filp);
2449         ide_drive_t *drive = tape->drive;
2450         struct ide_atapi_pc pc;
2451         unsigned int minor = iminor(inode);
2452
2453         lock_kernel();
2454         tape = drive->driver_data;
2455
2456         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2457
2458         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2459                 idetape_write_release(drive, minor);
2460         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2461                 if (minor < 128)
2462                         ide_tape_discard_merge_buffer(drive, 1);
2463         }
2464
2465         if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
2466                 (void) idetape_rewind_tape(drive);
2467         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2468                 if (tape->door_locked == DOOR_LOCKED) {
2469                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
2470                                 if (!idetape_queue_pc_tail(drive, &pc))
2471                                         tape->door_locked = DOOR_UNLOCKED;
2472                         }
2473                 }
2474         }
2475         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
2476         ide_tape_put(tape);
2477         unlock_kernel();
2478         return 0;
2479 }
2480
2481 /*
2482  * check the contents of the ATAPI IDENTIFY command results. We return:
2483  *
2484  * 1 - If the tape can be supported by us, based on the information we have so
2485  * far.
2486  *
2487  * 0 - If this tape driver is not currently supported by us.
2488  */
2489 static int idetape_identify_device(ide_drive_t *drive)
2490 {
2491         u8 gcw[2], protocol, device_type, removable, packet_size;
2492
2493         if (drive->id_read == 0)
2494                 return 1;
2495
2496         *((unsigned short *) &gcw) = drive->id->config;
2497
2498         protocol        =   (gcw[1] & 0xC0) >> 6;
2499         device_type     =    gcw[1] & 0x1F;
2500         removable       = !!(gcw[0] & 0x80);
2501         packet_size     =    gcw[0] & 0x3;
2502
2503         /* Check that we can support this device */
2504         if (protocol != 2)
2505                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
2506                                 protocol);
2507         else if (device_type != 1)
2508                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
2509                                 "to tape\n", device_type);
2510         else if (!removable)
2511                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
2512         else if (packet_size != 0) {
2513                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
2514                                 " bytes\n", packet_size);
2515         } else
2516                 return 1;
2517         return 0;
2518 }
2519
2520 static void idetape_get_inquiry_results(ide_drive_t *drive)
2521 {
2522         idetape_tape_t *tape = drive->driver_data;
2523         struct ide_atapi_pc pc;
2524         char fw_rev[6], vendor_id[10], product_id[18];
2525
2526         idetape_create_inquiry_cmd(&pc);
2527         if (idetape_queue_pc_tail(drive, &pc)) {
2528                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2529                                 tape->name);
2530                 return;
2531         }
2532         memcpy(vendor_id, &pc.buf[8], 8);
2533         memcpy(product_id, &pc.buf[16], 16);
2534         memcpy(fw_rev, &pc.buf[32], 4);
2535
2536         ide_fixstring(vendor_id, 10, 0);
2537         ide_fixstring(product_id, 18, 0);
2538         ide_fixstring(fw_rev, 6, 0);
2539
2540         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
2541                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2542 }
2543
2544 /*
2545  * Ask the tape about its various parameters. In particular, we will adjust our
2546  * data transfer buffer size to the recommended value as returned by the tape.
2547  */
2548 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2549 {
2550         idetape_tape_t *tape = drive->driver_data;
2551         struct ide_atapi_pc pc;
2552         u8 *caps;
2553         u8 speed, max_speed;
2554
2555         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2556         if (idetape_queue_pc_tail(drive, &pc)) {
2557                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2558                                 " some default values\n");
2559                 tape->blk_size = 512;
2560                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2561                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2562                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2563                 return;
2564         }
2565         caps = pc.buf + 4 + pc.buf[3];
2566
2567         /* convert to host order and save for later use */
2568         speed = be16_to_cpu(*(u16 *)&caps[14]);
2569         max_speed = be16_to_cpu(*(u16 *)&caps[8]);
2570
2571         put_unaligned(max_speed, (u16 *)&caps[8]);
2572         put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
2573         put_unaligned(speed, (u16 *)&caps[14]);
2574         put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
2575
2576         if (!speed) {
2577                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2578                                 "(assuming 650KB/sec)\n", drive->name);
2579                 put_unaligned(650, (u16 *)&caps[14]);
2580         }
2581         if (!max_speed) {
2582                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2583                                 "(assuming 650KB/sec)\n", drive->name);
2584                 put_unaligned(650, (u16 *)&caps[8]);
2585         }
2586
2587         memcpy(&tape->caps, caps, 20);
2588         if (caps[7] & 0x02)
2589                 tape->blk_size = 512;
2590         else if (caps[7] & 0x04)
2591                 tape->blk_size = 1024;
2592 }
2593
2594 #ifdef CONFIG_IDE_PROC_FS
2595 static void idetape_add_settings(ide_drive_t *drive)
2596 {
2597         idetape_tape_t *tape = drive->driver_data;
2598
2599         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2600                         1, 2, (u16 *)&tape->caps[16], NULL);
2601         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
2602                         1, 1, (u16 *)&tape->caps[14], NULL);
2603         ide_add_setting(drive, "buffer_size", SETTING_READ, TYPE_INT, 0, 0xffff,
2604                         1, 1024, &tape->buffer_size, NULL);
2605         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
2606                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
2607                         NULL);
2608         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
2609                         1, &drive->dsc_overlap, NULL);
2610         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
2611                         1, 1, &tape->avg_speed, NULL);
2612         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
2613                         1, &tape->debug_mask, NULL);
2614 }
2615 #else
2616 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
2617 #endif
2618
2619 /*
2620  * The function below is called to:
2621  *
2622  * 1. Initialize our various state variables.
2623  * 2. Ask the tape for its capabilities.
2624  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2625  * is chosen based on the recommendation which we received in step 2.
2626  *
2627  * Note that at this point ide.c already assigned us an irq, so that we can
2628  * queue requests here and wait for their completion.
2629  */
2630 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2631 {
2632         unsigned long t;
2633         int speed;
2634         int buffer_size;
2635         u8 gcw[2];
2636         u16 *ctl = (u16 *)&tape->caps[12];
2637
2638         spin_lock_init(&tape->lock);
2639         drive->dsc_overlap = 1;
2640         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2641                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2642                                  tape->name);
2643                 drive->dsc_overlap = 0;
2644         }
2645         /* Seagate Travan drives do not support DSC overlap. */
2646         if (strstr(drive->id->model, "Seagate STT3401"))
2647                 drive->dsc_overlap = 0;
2648         tape->minor = minor;
2649         tape->name[0] = 'h';
2650         tape->name[1] = 't';
2651         tape->name[2] = '0' + minor;
2652         tape->chrdev_dir = IDETAPE_DIR_NONE;
2653         tape->pc = tape->pc_stack;
2654         *((unsigned short *) &gcw) = drive->id->config;
2655
2656         /* Command packet DRQ type */
2657         if (((gcw[0] & 0x60) >> 5) == 1)
2658                 set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
2659
2660         idetape_get_inquiry_results(drive);
2661         idetape_get_mode_sense_results(drive);
2662         ide_tape_get_bsize_from_bdesc(drive);
2663         tape->user_bs_factor = 1;
2664         tape->buffer_size = *ctl * tape->blk_size;
2665         while (tape->buffer_size > 0xffff) {
2666                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2667                 *ctl /= 2;
2668                 tape->buffer_size = *ctl * tape->blk_size;
2669         }
2670         buffer_size = tape->buffer_size;
2671         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2672         if (buffer_size % PAGE_SIZE) {
2673                 tape->pages_per_buffer++;
2674                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2675         }
2676
2677         /* select the "best" DSC read/write polling freq */
2678         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2679
2680         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2681
2682         /*
2683          * Ensure that the number we got makes sense; limit it within
2684          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2685          */
2686         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2687                                          IDETAPE_DSC_RW_MAX);
2688         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2689                 "%lums tDSC%s\n",
2690                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2691                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2692                 tape->buffer_size / 1024,
2693                 tape->best_dsc_rw_freq * 1000 / HZ,
2694                 drive->using_dma ? ", DMA":"");
2695
2696         idetape_add_settings(drive);
2697 }
2698
2699 static void ide_tape_remove(ide_drive_t *drive)
2700 {
2701         idetape_tape_t *tape = drive->driver_data;
2702
2703         ide_proc_unregister_driver(drive, tape->driver);
2704
2705         ide_unregister_region(tape->disk);
2706
2707         ide_tape_put(tape);
2708 }
2709
2710 static void ide_tape_release(struct kref *kref)
2711 {
2712         struct ide_tape_obj *tape = to_ide_tape(kref);
2713         ide_drive_t *drive = tape->drive;
2714         struct gendisk *g = tape->disk;
2715
2716         BUG_ON(tape->merge_bh_size);
2717
2718         drive->dsc_overlap = 0;
2719         drive->driver_data = NULL;
2720         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2721         device_destroy(idetape_sysfs_class,
2722                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2723         idetape_devs[tape->minor] = NULL;
2724         g->private_data = NULL;
2725         put_disk(g);
2726         kfree(tape);
2727 }
2728
2729 #ifdef CONFIG_IDE_PROC_FS
2730 static int proc_idetape_read_name
2731         (char *page, char **start, off_t off, int count, int *eof, void *data)
2732 {
2733         ide_drive_t     *drive = (ide_drive_t *) data;
2734         idetape_tape_t  *tape = drive->driver_data;
2735         char            *out = page;
2736         int             len;
2737
2738         len = sprintf(out, "%s\n", tape->name);
2739         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2740 }
2741
2742 static ide_proc_entry_t idetape_proc[] = {
2743         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2744         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2745         { NULL, 0, NULL, NULL }
2746 };
2747 #endif
2748
2749 static int ide_tape_probe(ide_drive_t *);
2750
2751 static ide_driver_t idetape_driver = {
2752         .gen_driver = {
2753                 .owner          = THIS_MODULE,
2754                 .name           = "ide-tape",
2755                 .bus            = &ide_bus_type,
2756         },
2757         .probe                  = ide_tape_probe,
2758         .remove                 = ide_tape_remove,
2759         .version                = IDETAPE_VERSION,
2760         .media                  = ide_tape,
2761         .supports_dsc_overlap   = 1,
2762         .do_request             = idetape_do_request,
2763         .end_request            = idetape_end_request,
2764         .error                  = __ide_error,
2765         .abort                  = __ide_abort,
2766 #ifdef CONFIG_IDE_PROC_FS
2767         .proc                   = idetape_proc,
2768 #endif
2769 };
2770
2771 /* Our character device supporting functions, passed to register_chrdev. */
2772 static const struct file_operations idetape_fops = {
2773         .owner          = THIS_MODULE,
2774         .read           = idetape_chrdev_read,
2775         .write          = idetape_chrdev_write,
2776         .ioctl          = idetape_chrdev_ioctl,
2777         .open           = idetape_chrdev_open,
2778         .release        = idetape_chrdev_release,
2779 };
2780
2781 static int idetape_open(struct inode *inode, struct file *filp)
2782 {
2783         struct gendisk *disk = inode->i_bdev->bd_disk;
2784         struct ide_tape_obj *tape;
2785
2786         tape = ide_tape_get(disk);
2787         if (!tape)
2788                 return -ENXIO;
2789
2790         return 0;
2791 }
2792
2793 static int idetape_release(struct inode *inode, struct file *filp)
2794 {
2795         struct gendisk *disk = inode->i_bdev->bd_disk;
2796         struct ide_tape_obj *tape = ide_tape_g(disk);
2797
2798         ide_tape_put(tape);
2799
2800         return 0;
2801 }
2802
2803 static int idetape_ioctl(struct inode *inode, struct file *file,
2804                         unsigned int cmd, unsigned long arg)
2805 {
2806         struct block_device *bdev = inode->i_bdev;
2807         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2808         ide_drive_t *drive = tape->drive;
2809         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2810         if (err == -EINVAL)
2811                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2812         return err;
2813 }
2814
2815 static struct block_device_operations idetape_block_ops = {
2816         .owner          = THIS_MODULE,
2817         .open           = idetape_open,
2818         .release        = idetape_release,
2819         .ioctl          = idetape_ioctl,
2820 };
2821
2822 static int ide_tape_probe(ide_drive_t *drive)
2823 {
2824         idetape_tape_t *tape;
2825         struct gendisk *g;
2826         int minor;
2827
2828         if (!strstr("ide-tape", drive->driver_req))
2829                 goto failed;
2830         if (!drive->present)
2831                 goto failed;
2832         if (drive->media != ide_tape)
2833                 goto failed;
2834         if (!idetape_identify_device(drive)) {
2835                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2836                                 " the driver\n", drive->name);
2837                 goto failed;
2838         }
2839         if (drive->scsi) {
2840                 printk(KERN_INFO "ide-tape: passing drive %s to ide-scsi"
2841                                  " emulation.\n", drive->name);
2842                 goto failed;
2843         }
2844         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2845         if (tape == NULL) {
2846                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2847                                 drive->name);
2848                 goto failed;
2849         }
2850
2851         g = alloc_disk(1 << PARTN_BITS);
2852         if (!g)
2853                 goto out_free_tape;
2854
2855         ide_init_disk(g, drive);
2856
2857         ide_proc_register_driver(drive, &idetape_driver);
2858
2859         kref_init(&tape->kref);
2860
2861         tape->drive = drive;
2862         tape->driver = &idetape_driver;
2863         tape->disk = g;
2864
2865         g->private_data = &tape->driver;
2866
2867         drive->driver_data = tape;
2868
2869         mutex_lock(&idetape_ref_mutex);
2870         for (minor = 0; idetape_devs[minor]; minor++)
2871                 ;
2872         idetape_devs[minor] = tape;
2873         mutex_unlock(&idetape_ref_mutex);
2874
2875         idetape_setup(drive, tape, minor);
2876
2877         device_create(idetape_sysfs_class, &drive->gendev,
2878                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
2879         device_create(idetape_sysfs_class, &drive->gendev,
2880                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
2881
2882         g->fops = &idetape_block_ops;
2883         ide_register_region(g);
2884
2885         return 0;
2886
2887 out_free_tape:
2888         kfree(tape);
2889 failed:
2890         return -ENODEV;
2891 }
2892
2893 static void __exit idetape_exit(void)
2894 {
2895         driver_unregister(&idetape_driver.gen_driver);
2896         class_destroy(idetape_sysfs_class);
2897         unregister_chrdev(IDETAPE_MAJOR, "ht");
2898 }
2899
2900 static int __init idetape_init(void)
2901 {
2902         int error = 1;
2903         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2904         if (IS_ERR(idetape_sysfs_class)) {
2905                 idetape_sysfs_class = NULL;
2906                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2907                 error = -EBUSY;
2908                 goto out;
2909         }
2910
2911         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2912                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2913                                 " interface\n");
2914                 error = -EBUSY;
2915                 goto out_free_class;
2916         }
2917
2918         error = driver_register(&idetape_driver.gen_driver);
2919         if (error)
2920                 goto out_free_driver;
2921
2922         return 0;
2923
2924 out_free_driver:
2925         driver_unregister(&idetape_driver.gen_driver);
2926 out_free_class:
2927         class_destroy(idetape_sysfs_class);
2928 out:
2929         return error;
2930 }
2931
2932 MODULE_ALIAS("ide:*m-tape*");
2933 module_init(idetape_init);
2934 module_exit(idetape_exit);
2935 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2936 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2937 MODULE_LICENSE("GPL");