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