Merge branch 'merge-fixes' into devel
[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
77 /*
78  * Pipelined mode parameters.
79  *
80  * We try to use the minimum number of stages which is enough to keep the tape
81  * constantly streaming. To accomplish that, we implement a feedback loop around
82  * the maximum number of stages:
83  *
84  * We start from MIN maximum stages (we will not even use MIN stages if we don't
85  * need them), increment it by RATE*(MAX-MIN) whenever we sense that the
86  * pipeline is empty, until we reach the optimum value or until we reach MAX.
87  *
88  * Setting the following parameter to 0 is illegal: the pipelined mode cannot be
89  * disabled (idetape_calculate_speeds() divides by tape->max_stages.)
90  */
91 #define IDETAPE_MIN_PIPELINE_STAGES       1
92 #define IDETAPE_MAX_PIPELINE_STAGES     400
93 #define IDETAPE_INCREASE_STAGES_RATE     20
94
95 /*
96  * After each failed packet command we issue a request sense command and retry
97  * the packet command IDETAPE_MAX_PC_RETRIES times.
98  *
99  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
100  */
101 #define IDETAPE_MAX_PC_RETRIES          3
102
103 /*
104  * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
105  * bytes. This is used for several packet commands (Not for READ/WRITE commands)
106  */
107 #define IDETAPE_PC_BUFFER_SIZE          256
108
109 /*
110  *      In various places in the driver, we need to allocate storage
111  *      for packet commands and requests, which will remain valid while
112  *      we leave the driver to wait for an interrupt or a timeout event.
113  */
114 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
115
116 /*
117  * Some drives (for example, Seagate STT3401A Travan) require a very long
118  * timeout, because they don't return an interrupt or clear their busy bit
119  * until after the command completes (even retension commands).
120  */
121 #define IDETAPE_WAIT_CMD                (900*HZ)
122
123 /*
124  * The following parameter is used to select the point in the internal tape fifo
125  * in which we will start to refill the buffer. Decreasing the following
126  * parameter will improve the system's latency and interactive response, while
127  * using a high value might improve system throughput.
128  */
129 #define IDETAPE_FIFO_THRESHOLD          2
130
131 /*
132  * DSC polling parameters.
133  *
134  * Polling for DSC (a single bit in the status register) is a very important
135  * function in ide-tape. There are two cases in which we poll for DSC:
136  *
137  * 1. Before a read/write packet command, to ensure that we can transfer data
138  * from/to the tape's data buffers, without causing an actual media access.
139  * In case the tape is not ready yet, we take out our request from the device
140  * request queue, so that ide.c could service requests from the other device
141  * on the same interface in the meantime.
142  *
143  * 2. After the successful initialization of a "media access packet command",
144  * which is a command that can take a long time to complete (the interval can
145  * range from several seconds to even an hour). Again, we postpone our request
146  * in the middle to free the bus for the other device. The polling frequency
147  * here should be lower than the read/write frequency since those media access
148  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
149  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
150  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
151  *
152  * We also set a timeout for the timer, in case something goes wrong. The
153  * timeout should be longer then the maximum execution time of a tape operation.
154  */
155
156 /* DSC timings. */
157 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
158 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
159 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
160 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
161 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
162 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
163 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
164
165 /*************************** End of tunable parameters ***********************/
166
167 /* Read/Write error simulation */
168 #define SIMULATE_ERRORS                 0
169
170 /* tape directions */
171 enum {
172         IDETAPE_DIR_NONE  = (1 << 0),
173         IDETAPE_DIR_READ  = (1 << 1),
174         IDETAPE_DIR_WRITE = (1 << 2),
175 };
176
177 struct idetape_bh {
178         u32 b_size;
179         atomic_t b_count;
180         struct idetape_bh *b_reqnext;
181         char *b_data;
182 };
183
184 /* Tape door status */
185 #define DOOR_UNLOCKED                   0
186 #define DOOR_LOCKED                     1
187 #define DOOR_EXPLICITLY_LOCKED          2
188
189 /* Some defines for the SPACE command */
190 #define IDETAPE_SPACE_OVER_FILEMARK     1
191 #define IDETAPE_SPACE_TO_EOD            3
192
193 /* Some defines for the LOAD UNLOAD command */
194 #define IDETAPE_LU_LOAD_MASK            1
195 #define IDETAPE_LU_RETENSION_MASK       2
196 #define IDETAPE_LU_EOT_MASK             4
197
198 /*
199  * Special requests for our block device strategy routine.
200  *
201  * In order to service a character device command, we add special requests to
202  * the tail of our block device request queue and wait for their completion.
203  */
204
205 enum {
206         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
207         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
208         REQ_IDETAPE_READ        = (1 << 2),
209         REQ_IDETAPE_WRITE       = (1 << 3),
210 };
211
212 /* Error codes returned in rq->errors to the higher part of the driver. */
213 #define IDETAPE_ERROR_GENERAL           101
214 #define IDETAPE_ERROR_FILEMARK          102
215 #define IDETAPE_ERROR_EOD               103
216
217 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
218 #define IDETAPE_BLOCK_DESCRIPTOR        0
219 #define IDETAPE_CAPABILITIES_PAGE       0x2a
220
221 /* Tape flag bits values. */
222 enum {
223         IDETAPE_FLAG_IGNORE_DSC         = (1 << 0),
224         /* 0 When the tape position is unknown */
225         IDETAPE_FLAG_ADDRESS_VALID      = (1 << 1),
226         /* Device already opened */
227         IDETAPE_FLAG_BUSY                       = (1 << 2),
228         /* Error detected in a pipeline stage */
229         IDETAPE_FLAG_PIPELINE_ERR       = (1 << 3),
230         /* Attempt to auto-detect the current user block size */
231         IDETAPE_FLAG_DETECT_BS          = (1 << 4),
232         /* Currently on a filemark */
233         IDETAPE_FLAG_FILEMARK           = (1 << 5),
234         /* DRQ interrupt device */
235         IDETAPE_FLAG_DRQ_INTERRUPT      = (1 << 6),
236         /* pipeline active */
237         IDETAPE_FLAG_PIPELINE_ACTIVE    = (1 << 7),
238         /* 0 = no tape is loaded, so we don't rewind after ejecting */
239         IDETAPE_FLAG_MEDIUM_PRESENT     = (1 << 8),
240 };
241
242 /* A pipeline stage. */
243 typedef struct idetape_stage_s {
244         struct request rq;                      /* The corresponding request */
245         struct idetape_bh *bh;                  /* The data buffers */
246         struct idetape_stage_s *next;           /* Pointer to the next stage */
247 } idetape_stage_t;
248
249 /*
250  * Most of our global data which we need to save even as we leave the driver due
251  * to an interrupt or a timer event is stored in the struct defined below.
252  */
253 typedef struct ide_tape_obj {
254         ide_drive_t     *drive;
255         ide_driver_t    *driver;
256         struct gendisk  *disk;
257         struct kref     kref;
258
259         /*
260          *      Since a typical character device operation requires more
261          *      than one packet command, we provide here enough memory
262          *      for the maximum of interconnected packet commands.
263          *      The packet commands are stored in the circular array pc_stack.
264          *      pc_stack_index points to the last used entry, and warps around
265          *      to the start when we get to the last array entry.
266          *
267          *      pc points to the current processed packet command.
268          *
269          *      failed_pc points to the last failed packet command, or contains
270          *      NULL if we do not need to retry any packet command. This is
271          *      required since an additional packet command is needed before the
272          *      retry, to get detailed information on what went wrong.
273          */
274         /* Current packet command */
275         struct ide_atapi_pc *pc;
276         /* Last failed packet command */
277         struct ide_atapi_pc *failed_pc;
278         /* Packet command stack */
279         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
280         /* Next free packet command storage space */
281         int pc_stack_index;
282         struct request rq_stack[IDETAPE_PC_STACK];
283         /* We implement a circular array */
284         int rq_stack_index;
285
286         /*
287          * DSC polling variables.
288          *
289          * While polling for DSC we use postponed_rq to postpone the current
290          * request so that ide.c will be able to service pending requests on the
291          * other device. Note that at most we will have only one DSC (usually
292          * data transfer) request in the device request queue. Additional
293          * requests can be queued in our internal pipeline, but they will be
294          * visible to ide.c only one at a time.
295          */
296         struct request *postponed_rq;
297         /* The time in which we started polling for DSC */
298         unsigned long dsc_polling_start;
299         /* Timer used to poll for dsc */
300         struct timer_list dsc_timer;
301         /* Read/Write dsc polling frequency */
302         unsigned long best_dsc_rw_freq;
303         unsigned long dsc_poll_freq;
304         unsigned long dsc_timeout;
305
306         /* Read position information */
307         u8 partition;
308         /* Current block */
309         unsigned int first_frame;
310
311         /* Last error information */
312         u8 sense_key, asc, ascq;
313
314         /* Character device operation */
315         unsigned int minor;
316         /* device name */
317         char name[4];
318         /* Current character device data transfer direction */
319         u8 chrdev_dir;
320
321         /* tape block size, usually 512 or 1024 bytes */
322         unsigned short blk_size;
323         int user_bs_factor;
324
325         /* Copy of the tape's Capabilities and Mechanical Page */
326         u8 caps[20];
327
328         /*
329          * Active data transfer request parameters.
330          *
331          * At most, there is only one ide-tape originated data transfer request
332          * in the device request queue. This allows ide.c to easily service
333          * requests from the other device when we postpone our active request.
334          * In the pipelined operation mode, we use our internal pipeline
335          * structure to hold more data requests. The data buffer size is chosen
336          * based on the tape's recommendation.
337          */
338         /* ptr to the request which is waiting in the device request queue */
339         struct request *active_data_rq;
340         /* Data buffer size chosen based on the tape's recommendation */
341         int stage_size;
342         idetape_stage_t *merge_stage;
343         int merge_stage_size;
344         struct idetape_bh *bh;
345         char *b_data;
346         int b_count;
347
348         /*
349          * Pipeline parameters.
350          *
351          * To accomplish non-pipelined mode, we simply set the following
352          * variables to zero (or NULL, where appropriate).
353          */
354         /* Number of currently used stages */
355         int nr_stages;
356         /* Number of pending stages */
357         int nr_pending_stages;
358         /* We will not allocate more than this number of stages */
359         int max_stages, min_pipeline, max_pipeline;
360         /* The first stage which will be removed from the pipeline */
361         idetape_stage_t *first_stage;
362         /* The currently active stage */
363         idetape_stage_t *active_stage;
364         /* Will be serviced after the currently active request */
365         idetape_stage_t *next_stage;
366         /* New requests will be added to the pipeline here */
367         idetape_stage_t *last_stage;
368         /* Optional free stage which we can use */
369         idetape_stage_t *cache_stage;
370         int pages_per_stage;
371         /* Wasted space in each stage */
372         int excess_bh_size;
373
374         /* Status/Action flags: long for set_bit */
375         unsigned long flags;
376         /* protects the ide-tape queue */
377         spinlock_t lock;
378
379         /* Measures average tape speed */
380         unsigned long avg_time;
381         int avg_size;
382         int avg_speed;
383
384         /* the door is currently locked */
385         int door_locked;
386         /* the tape hardware is write protected */
387         char drv_write_prot;
388         /* the tape is write protected (hardware or opened as read-only) */
389         char write_prot;
390
391         /*
392          * Limit the number of times a request can be postponed, to avoid an
393          * infinite postpone deadlock.
394          */
395         int postpone_cnt;
396
397         /*
398          * Measures number of frames:
399          *
400          * 1. written/read to/from the driver pipeline (pipeline_head).
401          * 2. written/read to/from the tape buffers (idetape_bh).
402          * 3. written/read by the tape to/from the media (tape_head).
403          */
404         int pipeline_head;
405         int buffer_head;
406         int tape_head;
407         int last_tape_head;
408
409         /* Speed control at the tape buffers input/output */
410         unsigned long insert_time;
411         int insert_size;
412         int insert_speed;
413         int max_insert_speed;
414         int measure_insert_time;
415
416         /* Speed regulation negative feedback loop */
417         int speed_control;
418         int pipeline_head_speed;
419         int controlled_pipeline_head_speed;
420         int uncontrolled_pipeline_head_speed;
421         int controlled_last_pipeline_head;
422         unsigned long uncontrolled_pipeline_head_time;
423         unsigned long controlled_pipeline_head_time;
424         int controlled_previous_pipeline_head;
425         int uncontrolled_previous_pipeline_head;
426         unsigned long controlled_previous_head_time;
427         unsigned long uncontrolled_previous_head_time;
428         int restart_speed_control_req;
429
430         u32 debug_mask;
431 } idetape_tape_t;
432
433 static DEFINE_MUTEX(idetape_ref_mutex);
434
435 static struct class *idetape_sysfs_class;
436
437 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
438
439 #define ide_tape_g(disk) \
440         container_of((disk)->private_data, struct ide_tape_obj, driver)
441
442 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
443 {
444         struct ide_tape_obj *tape = NULL;
445
446         mutex_lock(&idetape_ref_mutex);
447         tape = ide_tape_g(disk);
448         if (tape)
449                 kref_get(&tape->kref);
450         mutex_unlock(&idetape_ref_mutex);
451         return tape;
452 }
453
454 static void ide_tape_release(struct kref *);
455
456 static void ide_tape_put(struct ide_tape_obj *tape)
457 {
458         mutex_lock(&idetape_ref_mutex);
459         kref_put(&tape->kref, ide_tape_release);
460         mutex_unlock(&idetape_ref_mutex);
461 }
462
463 /*
464  * The variables below are used for the character device interface. Additional
465  * state variables are defined in our ide_drive_t structure.
466  */
467 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
468
469 #define ide_tape_f(file) ((file)->private_data)
470
471 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
472 {
473         struct ide_tape_obj *tape = NULL;
474
475         mutex_lock(&idetape_ref_mutex);
476         tape = idetape_devs[i];
477         if (tape)
478                 kref_get(&tape->kref);
479         mutex_unlock(&idetape_ref_mutex);
480         return tape;
481 }
482
483 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
484                                   unsigned int bcount)
485 {
486         struct idetape_bh *bh = pc->bh;
487         int count;
488
489         while (bcount) {
490                 if (bh == NULL) {
491                         printk(KERN_ERR "ide-tape: bh == NULL in "
492                                 "idetape_input_buffers\n");
493                         ide_atapi_discard_data(drive, bcount);
494                         return;
495                 }
496                 count = min(
497                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
498                         bcount);
499                 HWIF(drive)->atapi_input_bytes(drive, bh->b_data +
500                                         atomic_read(&bh->b_count), count);
501                 bcount -= count;
502                 atomic_add(count, &bh->b_count);
503                 if (atomic_read(&bh->b_count) == bh->b_size) {
504                         bh = bh->b_reqnext;
505                         if (bh)
506                                 atomic_set(&bh->b_count, 0);
507                 }
508         }
509         pc->bh = bh;
510 }
511
512 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
513                                    unsigned int bcount)
514 {
515         struct idetape_bh *bh = pc->bh;
516         int count;
517
518         while (bcount) {
519                 if (bh == NULL) {
520                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
521                                         __func__);
522                         return;
523                 }
524                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
525                 HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
526                 bcount -= count;
527                 pc->b_data += count;
528                 pc->b_count -= count;
529                 if (!pc->b_count) {
530                         bh = bh->b_reqnext;
531                         pc->bh = bh;
532                         if (bh) {
533                                 pc->b_data = bh->b_data;
534                                 pc->b_count = atomic_read(&bh->b_count);
535                         }
536                 }
537         }
538 }
539
540 static void idetape_update_buffers(struct ide_atapi_pc *pc)
541 {
542         struct idetape_bh *bh = pc->bh;
543         int count;
544         unsigned int bcount = pc->xferred;
545
546         if (pc->flags & PC_FLAG_WRITING)
547                 return;
548         while (bcount) {
549                 if (bh == NULL) {
550                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
551                                         __func__);
552                         return;
553                 }
554                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
555                 atomic_set(&bh->b_count, count);
556                 if (atomic_read(&bh->b_count) == bh->b_size)
557                         bh = bh->b_reqnext;
558                 bcount -= count;
559         }
560         pc->bh = bh;
561 }
562
563 /*
564  *      idetape_next_pc_storage returns a pointer to a place in which we can
565  *      safely store a packet command, even though we intend to leave the
566  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
567  *      commands is allocated at initialization time.
568  */
569 static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
570 {
571         idetape_tape_t *tape = drive->driver_data;
572
573         debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
574
575         if (tape->pc_stack_index == IDETAPE_PC_STACK)
576                 tape->pc_stack_index = 0;
577         return (&tape->pc_stack[tape->pc_stack_index++]);
578 }
579
580 /*
581  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
582  *      Since we queue packet commands in the request queue, we need to
583  *      allocate a request, along with the allocation of a packet command.
584  */
585
586 /**************************************************************
587  *                                                            *
588  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
589  *  followed later on by kfree().   -ml                       *
590  *                                                            *
591  **************************************************************/
592
593 static struct request *idetape_next_rq_storage(ide_drive_t *drive)
594 {
595         idetape_tape_t *tape = drive->driver_data;
596
597         debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
598
599         if (tape->rq_stack_index == IDETAPE_PC_STACK)
600                 tape->rq_stack_index = 0;
601         return (&tape->rq_stack[tape->rq_stack_index++]);
602 }
603
604 static void idetape_init_pc(struct ide_atapi_pc *pc)
605 {
606         memset(pc->c, 0, 12);
607         pc->retries = 0;
608         pc->flags = 0;
609         pc->req_xfer = 0;
610         pc->buf = pc->pc_buf;
611         pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
612         pc->bh = NULL;
613         pc->b_data = NULL;
614 }
615
616 /*
617  * called on each failed packet command retry to analyze the request sense. We
618  * currently do not utilize this information.
619  */
620 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
621 {
622         idetape_tape_t *tape = drive->driver_data;
623         struct ide_atapi_pc *pc = tape->failed_pc;
624
625         tape->sense_key = sense[2] & 0xF;
626         tape->asc       = sense[12];
627         tape->ascq      = sense[13];
628
629         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
630                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
631
632         /* Correct pc->xferred by asking the tape.       */
633         if (pc->flags & PC_FLAG_DMA_ERROR) {
634                 pc->xferred = pc->req_xfer -
635                         tape->blk_size *
636                         be32_to_cpu(get_unaligned((u32 *)&sense[3]));
637                 idetape_update_buffers(pc);
638         }
639
640         /*
641          * If error was the result of a zero-length read or write command,
642          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
643          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
644          */
645         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
646             /* length == 0 */
647             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
648                 if (tape->sense_key == 5) {
649                         /* don't report an error, everything's ok */
650                         pc->error = 0;
651                         /* don't retry read/write */
652                         pc->flags |= PC_FLAG_ABORT;
653                 }
654         }
655         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
656                 pc->error = IDETAPE_ERROR_FILEMARK;
657                 pc->flags |= PC_FLAG_ABORT;
658         }
659         if (pc->c[0] == WRITE_6) {
660                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
661                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
662                         pc->error = IDETAPE_ERROR_EOD;
663                         pc->flags |= PC_FLAG_ABORT;
664                 }
665         }
666         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
667                 if (tape->sense_key == 8) {
668                         pc->error = IDETAPE_ERROR_EOD;
669                         pc->flags |= PC_FLAG_ABORT;
670                 }
671                 if (!(pc->flags & PC_FLAG_ABORT) &&
672                     pc->xferred)
673                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
674         }
675 }
676
677 static void idetape_activate_next_stage(ide_drive_t *drive)
678 {
679         idetape_tape_t *tape = drive->driver_data;
680         idetape_stage_t *stage = tape->next_stage;
681         struct request *rq = &stage->rq;
682
683         debug_log(DBG_PROCS, "Enter %s\n", __func__);
684
685         if (stage == NULL) {
686                 printk(KERN_ERR "ide-tape: bug: Trying to activate a non"
687                                 " existing stage\n");
688                 return;
689         }
690
691         rq->rq_disk = tape->disk;
692         rq->buffer = NULL;
693         rq->special = (void *)stage->bh;
694         tape->active_data_rq = rq;
695         tape->active_stage = stage;
696         tape->next_stage = stage->next;
697 }
698
699 /* Free a stage along with its related buffers completely. */
700 static void __idetape_kfree_stage(idetape_stage_t *stage)
701 {
702         struct idetape_bh *prev_bh, *bh = stage->bh;
703         int size;
704
705         while (bh != NULL) {
706                 if (bh->b_data != NULL) {
707                         size = (int) bh->b_size;
708                         while (size > 0) {
709                                 free_page((unsigned long) bh->b_data);
710                                 size -= PAGE_SIZE;
711                                 bh->b_data += PAGE_SIZE;
712                         }
713                 }
714                 prev_bh = bh;
715                 bh = bh->b_reqnext;
716                 kfree(prev_bh);
717         }
718         kfree(stage);
719 }
720
721 static void idetape_kfree_stage(idetape_tape_t *tape, idetape_stage_t *stage)
722 {
723         __idetape_kfree_stage(stage);
724 }
725
726 /*
727  * Remove tape->first_stage from the pipeline. The caller should avoid race
728  * conditions.
729  */
730 static void idetape_remove_stage_head(ide_drive_t *drive)
731 {
732         idetape_tape_t *tape = drive->driver_data;
733         idetape_stage_t *stage;
734
735         debug_log(DBG_PROCS, "Enter %s\n", __func__);
736
737         if (tape->first_stage == NULL) {
738                 printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
739                 return;
740         }
741         if (tape->active_stage == tape->first_stage) {
742                 printk(KERN_ERR "ide-tape: bug: Trying to free our active "
743                                 "pipeline stage\n");
744                 return;
745         }
746         stage = tape->first_stage;
747         tape->first_stage = stage->next;
748         idetape_kfree_stage(tape, stage);
749         tape->nr_stages--;
750         if (tape->first_stage == NULL) {
751                 tape->last_stage = NULL;
752                 if (tape->next_stage != NULL)
753                         printk(KERN_ERR "ide-tape: bug: tape->next_stage !="
754                                         " NULL\n");
755                 if (tape->nr_stages)
756                         printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 "
757                                         "now\n");
758         }
759 }
760
761 /*
762  * This will free all the pipeline stages starting from new_last_stage->next
763  * to the end of the list, and point tape->last_stage to new_last_stage.
764  */
765 static void idetape_abort_pipeline(ide_drive_t *drive,
766                                    idetape_stage_t *new_last_stage)
767 {
768         idetape_tape_t *tape = drive->driver_data;
769         idetape_stage_t *stage = new_last_stage->next;
770         idetape_stage_t *nstage;
771
772         debug_log(DBG_PROCS, "%s: Enter %s\n", tape->name, __func__);
773
774         while (stage) {
775                 nstage = stage->next;
776                 idetape_kfree_stage(tape, stage);
777                 --tape->nr_stages;
778                 --tape->nr_pending_stages;
779                 stage = nstage;
780         }
781         if (new_last_stage)
782                 new_last_stage->next = NULL;
783         tape->last_stage = new_last_stage;
784         tape->next_stage = NULL;
785 }
786
787 /*
788  * Finish servicing a request and insert a pending pipeline request into the
789  * main device queue.
790  */
791 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
792 {
793         struct request *rq = HWGROUP(drive)->rq;
794         idetape_tape_t *tape = drive->driver_data;
795         unsigned long flags;
796         int error;
797         int remove_stage = 0;
798         idetape_stage_t *active_stage;
799
800         debug_log(DBG_PROCS, "Enter %s\n", __func__);
801
802         switch (uptodate) {
803         case 0: error = IDETAPE_ERROR_GENERAL; break;
804         case 1: error = 0; break;
805         default: error = uptodate;
806         }
807         rq->errors = error;
808         if (error)
809                 tape->failed_pc = NULL;
810
811         if (!blk_special_request(rq)) {
812                 ide_end_request(drive, uptodate, nr_sects);
813                 return 0;
814         }
815
816         spin_lock_irqsave(&tape->lock, flags);
817
818         /* The request was a pipelined data transfer request */
819         if (tape->active_data_rq == rq) {
820                 active_stage = tape->active_stage;
821                 tape->active_stage = NULL;
822                 tape->active_data_rq = NULL;
823                 tape->nr_pending_stages--;
824                 if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
825                         remove_stage = 1;
826                         if (error) {
827                                 set_bit(IDETAPE_FLAG_PIPELINE_ERR,
828                                         &tape->flags);
829                                 if (error == IDETAPE_ERROR_EOD)
830                                         idetape_abort_pipeline(drive,
831                                                                 active_stage);
832                         }
833                 } else if (rq->cmd[0] & REQ_IDETAPE_READ) {
834                         if (error == IDETAPE_ERROR_EOD) {
835                                 set_bit(IDETAPE_FLAG_PIPELINE_ERR,
836                                         &tape->flags);
837                                 idetape_abort_pipeline(drive, active_stage);
838                         }
839                 }
840                 if (tape->next_stage != NULL) {
841                         idetape_activate_next_stage(drive);
842
843                         /* Insert the next request into the request queue. */
844                         (void)ide_do_drive_cmd(drive, tape->active_data_rq,
845                                                 ide_end);
846                 } else if (!error) {
847                         /*
848                          * This is a part of the feedback loop which tries to
849                          * find the optimum number of stages. We are starting
850                          * from a minimum maximum number of stages, and if we
851                          * sense that the pipeline is empty, we try to increase
852                          * it, until we reach the user compile time memory
853                          * limit.
854                          */
855                         int i = (tape->max_pipeline - tape->min_pipeline) / 10;
856
857                         tape->max_stages += max(i, 1);
858                         tape->max_stages = max(tape->max_stages,
859                                                 tape->min_pipeline);
860                         tape->max_stages = min(tape->max_stages,
861                                                 tape->max_pipeline);
862                 }
863         }
864         ide_end_drive_cmd(drive, 0, 0);
865
866         if (remove_stage)
867                 idetape_remove_stage_head(drive);
868         if (tape->active_data_rq == NULL)
869                 clear_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
870         spin_unlock_irqrestore(&tape->lock, flags);
871         return 0;
872 }
873
874 static ide_startstop_t idetape_request_sense_callback(ide_drive_t *drive)
875 {
876         idetape_tape_t *tape = drive->driver_data;
877
878         debug_log(DBG_PROCS, "Enter %s\n", __func__);
879
880         if (!tape->pc->error) {
881                 idetape_analyze_error(drive, tape->pc->buf);
882                 idetape_end_request(drive, 1, 0);
883         } else {
884                 printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - "
885                                 "Aborting request!\n");
886                 idetape_end_request(drive, 0, 0);
887         }
888         return ide_stopped;
889 }
890
891 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
892 {
893         idetape_init_pc(pc);
894         pc->c[0] = REQUEST_SENSE;
895         pc->c[4] = 20;
896         pc->req_xfer = 20;
897         pc->idetape_callback = &idetape_request_sense_callback;
898 }
899
900 static void idetape_init_rq(struct request *rq, u8 cmd)
901 {
902         memset(rq, 0, sizeof(*rq));
903         rq->cmd_type = REQ_TYPE_SPECIAL;
904         rq->cmd[0] = cmd;
905 }
906
907 /*
908  * Generate a new packet command request in front of the request queue, before
909  * the current request, so that it will be processed immediately, on the next
910  * pass through the driver. The function below is called from the request
911  * handling part of the driver (the "bottom" part). Safe storage for the request
912  * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
913  *
914  * Memory for those requests is pre-allocated at initialization time, and is
915  * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
916  * the maximum possible number of inter-dependent packet commands.
917  *
918  * The higher level of the driver - The ioctl handler and the character device
919  * handling functions should queue request to the lower level part and wait for
920  * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
921  */
922 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
923                                   struct request *rq)
924 {
925         struct ide_tape_obj *tape = drive->driver_data;
926
927         idetape_init_rq(rq, REQ_IDETAPE_PC1);
928         rq->buffer = (char *) pc;
929         rq->rq_disk = tape->disk;
930         (void) ide_do_drive_cmd(drive, rq, ide_preempt);
931 }
932
933 /*
934  *      idetape_retry_pc is called when an error was detected during the
935  *      last packet command. We queue a request sense packet command in
936  *      the head of the request list.
937  */
938 static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
939 {
940         idetape_tape_t *tape = drive->driver_data;
941         struct ide_atapi_pc *pc;
942         struct request *rq;
943
944         (void)ide_read_error(drive);
945         pc = idetape_next_pc_storage(drive);
946         rq = idetape_next_rq_storage(drive);
947         idetape_create_request_sense_cmd(pc);
948         set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
949         idetape_queue_pc_head(drive, pc, rq);
950         return ide_stopped;
951 }
952
953 /*
954  * Postpone the current request so that ide.c will be able to service requests
955  * from another device on the same hwgroup while we are polling for DSC.
956  */
957 static void idetape_postpone_request(ide_drive_t *drive)
958 {
959         idetape_tape_t *tape = drive->driver_data;
960
961         debug_log(DBG_PROCS, "Enter %s\n", __func__);
962
963         tape->postponed_rq = HWGROUP(drive)->rq;
964         ide_stall_queue(drive, tape->dsc_poll_freq);
965 }
966
967 typedef void idetape_io_buf(ide_drive_t *, struct ide_atapi_pc *, unsigned int);
968
969 /*
970  * This is the usual interrupt handler which will be called during a packet
971  * command. We will transfer some of the data (as requested by the drive) and
972  * will re-point interrupt handler to us. When data transfer is finished, we
973  * will act according to the algorithm described before
974  * idetape_issue_pc.
975  */
976 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
977 {
978         ide_hwif_t *hwif = drive->hwif;
979         idetape_tape_t *tape = drive->driver_data;
980         struct ide_atapi_pc *pc = tape->pc;
981         xfer_func_t *xferfunc;
982         idetape_io_buf *iobuf;
983         unsigned int temp;
984 #if SIMULATE_ERRORS
985         static int error_sim_count;
986 #endif
987         u16 bcount;
988         u8 stat, ireason;
989
990         debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
991
992         /* Clear the interrupt */
993         stat = ide_read_status(drive);
994
995         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
996                 if (hwif->ide_dma_end(drive) || (stat & ERR_STAT)) {
997                         /*
998                          * A DMA error is sometimes expected. For example,
999                          * if the tape is crossing a filemark during a
1000                          * READ command, it will issue an irq and position
1001                          * itself before the filemark, so that only a partial
1002                          * data transfer will occur (which causes the DMA
1003                          * error). In that case, we will later ask the tape
1004                          * how much bytes of the original request were
1005                          * actually transferred (we can't receive that
1006                          * information from the DMA engine on most chipsets).
1007                          */
1008
1009                         /*
1010                          * On the contrary, a DMA error is never expected;
1011                          * it usually indicates a hardware error or abort.
1012                          * If the tape crosses a filemark during a READ
1013                          * command, it will issue an irq and position itself
1014                          * after the filemark (not before). Only a partial
1015                          * data transfer will occur, but no DMA error.
1016                          * (AS, 19 Apr 2001)
1017                          */
1018                         pc->flags |= PC_FLAG_DMA_ERROR;
1019                 } else {
1020                         pc->xferred = pc->req_xfer;
1021                         idetape_update_buffers(pc);
1022                 }
1023                 debug_log(DBG_PROCS, "DMA finished\n");
1024
1025         }
1026
1027         /* No more interrupts */
1028         if ((stat & DRQ_STAT) == 0) {
1029                 debug_log(DBG_SENSE, "Packet command completed, %d bytes"
1030                                 " transferred\n", pc->xferred);
1031
1032                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
1033                 local_irq_enable();
1034
1035 #if SIMULATE_ERRORS
1036                 if ((pc->c[0] == WRITE_6 || pc->c[0] == READ_6) &&
1037                     (++error_sim_count % 100) == 0) {
1038                         printk(KERN_INFO "ide-tape: %s: simulating error\n",
1039                                 tape->name);
1040                         stat |= ERR_STAT;
1041                 }
1042 #endif
1043                 if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
1044                         stat &= ~ERR_STAT;
1045                 if ((stat & ERR_STAT) || (pc->flags & PC_FLAG_DMA_ERROR)) {
1046                         /* Error detected */
1047                         debug_log(DBG_ERR, "%s: I/O error\n", tape->name);
1048
1049                         if (pc->c[0] == REQUEST_SENSE) {
1050                                 printk(KERN_ERR "ide-tape: I/O error in request"
1051                                                 " sense command\n");
1052                                 return ide_do_reset(drive);
1053                         }
1054                         debug_log(DBG_ERR, "[cmd %x]: check condition\n",
1055                                         pc->c[0]);
1056
1057                         /* Retry operation */
1058                         return idetape_retry_pc(drive);
1059                 }
1060                 pc->error = 0;
1061                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
1062                     (stat & SEEK_STAT) == 0) {
1063                         /* Media access command */
1064                         tape->dsc_polling_start = jiffies;
1065                         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
1066                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
1067                         /* Allow ide.c to handle other requests */
1068                         idetape_postpone_request(drive);
1069                         return ide_stopped;
1070                 }
1071                 if (tape->failed_pc == pc)
1072                         tape->failed_pc = NULL;
1073                 /* Command finished - Call the callback function */
1074                 return pc->idetape_callback(drive);
1075         }
1076
1077         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
1078                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
1079                 printk(KERN_ERR "ide-tape: The tape wants to issue more "
1080                                 "interrupts in DMA mode\n");
1081                 printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1082                 ide_dma_off(drive);
1083                 return ide_do_reset(drive);
1084         }
1085         /* Get the number of bytes to transfer on this interrupt. */
1086         bcount = (hwif->INB(hwif->io_ports[IDE_BCOUNTH_OFFSET]) << 8) |
1087                   hwif->INB(hwif->io_ports[IDE_BCOUNTL_OFFSET]);
1088
1089         ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
1090
1091         if (ireason & CD) {
1092                 printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
1093                 return ide_do_reset(drive);
1094         }
1095         if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
1096                 /* Hopefully, we will never get here */
1097                 printk(KERN_ERR "ide-tape: We wanted to %s, ",
1098                                 (ireason & IO) ? "Write" : "Read");
1099                 printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1100                                 (ireason & IO) ? "Read" : "Write");
1101                 return ide_do_reset(drive);
1102         }
1103         if (!(pc->flags & PC_FLAG_WRITING)) {
1104                 /* Reading - Check that we have enough space */
1105                 temp = pc->xferred + bcount;
1106                 if (temp > pc->req_xfer) {
1107                         if (temp > pc->buf_size) {
1108                                 printk(KERN_ERR "ide-tape: The tape wants to "
1109                                         "send us more data than expected "
1110                                         "- discarding data\n");
1111                                 ide_atapi_discard_data(drive, bcount);
1112                                 ide_set_handler(drive, &idetape_pc_intr,
1113                                                 IDETAPE_WAIT_CMD, NULL);
1114                                 return ide_started;
1115                         }
1116                         debug_log(DBG_SENSE, "The tape wants to send us more "
1117                                 "data than expected - allowing transfer\n");
1118                 }
1119                 iobuf = &idetape_input_buffers;
1120                 xferfunc = hwif->atapi_input_bytes;
1121         } else {
1122                 iobuf = &idetape_output_buffers;
1123                 xferfunc = hwif->atapi_output_bytes;
1124         }
1125
1126         if (pc->bh)
1127                 iobuf(drive, pc, bcount);
1128         else
1129                 xferfunc(drive, pc->cur_pos, bcount);
1130
1131         /* Update the current position */
1132         pc->xferred += bcount;
1133         pc->cur_pos += bcount;
1134
1135         debug_log(DBG_SENSE, "[cmd %x] transferred %d bytes on that intr.\n",
1136                         pc->c[0], bcount);
1137
1138         /* And set the interrupt handler again */
1139         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
1140         return ide_started;
1141 }
1142
1143 /*
1144  * Packet Command Interface
1145  *
1146  * The current Packet Command is available in tape->pc, and will not change
1147  * until we finish handling it. Each packet command is associated with a
1148  * callback function that will be called when the command is finished.
1149  *
1150  * The handling will be done in three stages:
1151  *
1152  * 1. idetape_issue_pc will send the packet command to the drive, and will set
1153  * the interrupt handler to idetape_pc_intr.
1154  *
1155  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
1156  * repeated until the device signals us that no more interrupts will be issued.
1157  *
1158  * 3. ATAPI Tape media access commands have immediate status with a delayed
1159  * process. In case of a successful initiation of a media access packet command,
1160  * the DSC bit will be set when the actual execution of the command is finished.
1161  * Since the tape drive will not issue an interrupt, we have to poll for this
1162  * event. In this case, we define the request as "low priority request" by
1163  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
1164  * exit the driver.
1165  *
1166  * ide.c will then give higher priority to requests which originate from the
1167  * other device, until will change rq_status to RQ_ACTIVE.
1168  *
1169  * 4. When the packet command is finished, it will be checked for errors.
1170  *
1171  * 5. In case an error was found, we queue a request sense packet command in
1172  * front of the request queue and retry the operation up to
1173  * IDETAPE_MAX_PC_RETRIES times.
1174  *
1175  * 6. In case no error was found, or we decided to give up and not to retry
1176  * again, the callback function will be called and then we will handle the next
1177  * request.
1178  */
1179 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
1180 {
1181         ide_hwif_t *hwif = drive->hwif;
1182         idetape_tape_t *tape = drive->driver_data;
1183         struct ide_atapi_pc *pc = tape->pc;
1184         int retries = 100;
1185         ide_startstop_t startstop;
1186         u8 ireason;
1187
1188         if (ide_wait_stat(&startstop, drive, DRQ_STAT, BUSY_STAT, WAIT_READY)) {
1189                 printk(KERN_ERR "ide-tape: Strange, packet command initiated "
1190                                 "yet DRQ isn't asserted\n");
1191                 return startstop;
1192         }
1193         ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
1194         while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
1195                 printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
1196                                 "a packet command, retrying\n");
1197                 udelay(100);
1198                 ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
1199                 if (retries == 0) {
1200                         printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
1201                                         "issuing a packet command, ignoring\n");
1202                         ireason |= CD;
1203                         ireason &= ~IO;
1204                 }
1205         }
1206         if ((ireason & CD) == 0 || (ireason & IO)) {
1207                 printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
1208                                 "a packet command\n");
1209                 return ide_do_reset(drive);
1210         }
1211         /* Set the interrupt routine */
1212         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
1213 #ifdef CONFIG_BLK_DEV_IDEDMA
1214         /* Begin DMA, if necessary */
1215         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS)
1216                 hwif->dma_start(drive);
1217 #endif
1218         /* Send the actual packet */
1219         HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
1220         return ide_started;
1221 }
1222
1223 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
1224                 struct ide_atapi_pc *pc)
1225 {
1226         ide_hwif_t *hwif = drive->hwif;
1227         idetape_tape_t *tape = drive->driver_data;
1228         int dma_ok = 0;
1229         u16 bcount;
1230
1231         if (tape->pc->c[0] == REQUEST_SENSE &&
1232             pc->c[0] == REQUEST_SENSE) {
1233                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
1234                         "Two request sense in serial were issued\n");
1235         }
1236
1237         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
1238                 tape->failed_pc = pc;
1239         /* Set the current packet command */
1240         tape->pc = pc;
1241
1242         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
1243                 (pc->flags & PC_FLAG_ABORT)) {
1244                 /*
1245                  * We will "abort" retrying a packet command in case legitimate
1246                  * error code was received (crossing a filemark, or end of the
1247                  * media, for example).
1248                  */
1249                 if (!(pc->flags & PC_FLAG_ABORT)) {
1250                         if (!(pc->c[0] == TEST_UNIT_READY &&
1251                               tape->sense_key == 2 && tape->asc == 4 &&
1252                              (tape->ascq == 1 || tape->ascq == 8))) {
1253                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
1254                                                 "pc = %2x, key = %2x, "
1255                                                 "asc = %2x, ascq = %2x\n",
1256                                                 tape->name, pc->c[0],
1257                                                 tape->sense_key, tape->asc,
1258                                                 tape->ascq);
1259                         }
1260                         /* Giving up */
1261                         pc->error = IDETAPE_ERROR_GENERAL;
1262                 }
1263                 tape->failed_pc = NULL;
1264                 return pc->idetape_callback(drive);
1265         }
1266         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
1267
1268         pc->retries++;
1269         /* We haven't transferred any data yet */
1270         pc->xferred = 0;
1271         pc->cur_pos = pc->buf;
1272         /* Request to transfer the entire buffer at once */
1273         bcount = pc->req_xfer;
1274
1275         if (pc->flags & PC_FLAG_DMA_ERROR) {
1276                 pc->flags &= ~PC_FLAG_DMA_ERROR;
1277                 printk(KERN_WARNING "ide-tape: DMA disabled, "
1278                                 "reverting to PIO\n");
1279                 ide_dma_off(drive);
1280         }
1281         if ((pc->flags & PC_FLAG_DMA_RECOMMENDED) && drive->using_dma)
1282                 dma_ok = !hwif->dma_setup(drive);
1283
1284         ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK |
1285                            IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
1286
1287         if (dma_ok)
1288                 /* Will begin DMA later */
1289                 pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
1290         if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags)) {
1291                 ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
1292                                     IDETAPE_WAIT_CMD, NULL);
1293                 return ide_started;
1294         } else {
1295                 hwif->OUTB(WIN_PACKETCMD, hwif->io_ports[IDE_COMMAND_OFFSET]);
1296                 return idetape_transfer_pc(drive);
1297         }
1298 }
1299
1300 static ide_startstop_t idetape_pc_callback(ide_drive_t *drive)
1301 {
1302         idetape_tape_t *tape = drive->driver_data;
1303
1304         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1305
1306         idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
1307         return ide_stopped;
1308 }
1309
1310 /* A mode sense command is used to "sense" tape parameters. */
1311 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
1312 {
1313         idetape_init_pc(pc);
1314         pc->c[0] = MODE_SENSE;
1315         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1316                 /* DBD = 1 - Don't return block descriptors */
1317                 pc->c[1] = 8;
1318         pc->c[2] = page_code;
1319         /*
1320          * Changed pc->c[3] to 0 (255 will at best return unused info).
1321          *
1322          * For SCSI this byte is defined as subpage instead of high byte
1323          * of length and some IDE drives seem to interpret it this way
1324          * and return an error when 255 is used.
1325          */
1326         pc->c[3] = 0;
1327         /* We will just discard data in that case */
1328         pc->c[4] = 255;
1329         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1330                 pc->req_xfer = 12;
1331         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
1332                 pc->req_xfer = 24;
1333         else
1334                 pc->req_xfer = 50;
1335         pc->idetape_callback = &idetape_pc_callback;
1336 }
1337
1338 static void idetape_calculate_speeds(ide_drive_t *drive)
1339 {
1340         idetape_tape_t *tape = drive->driver_data;
1341
1342         if (time_after(jiffies,
1343                         tape->controlled_pipeline_head_time + 120 * HZ)) {
1344                 tape->controlled_previous_pipeline_head =
1345                         tape->controlled_last_pipeline_head;
1346                 tape->controlled_previous_head_time =
1347                         tape->controlled_pipeline_head_time;
1348                 tape->controlled_last_pipeline_head = tape->pipeline_head;
1349                 tape->controlled_pipeline_head_time = jiffies;
1350         }
1351         if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
1352                 tape->controlled_pipeline_head_speed = (tape->pipeline_head -
1353                                 tape->controlled_last_pipeline_head) * 32 * HZ /
1354                                 (jiffies - tape->controlled_pipeline_head_time);
1355         else if (time_after(jiffies, tape->controlled_previous_head_time))
1356                 tape->controlled_pipeline_head_speed = (tape->pipeline_head -
1357                                 tape->controlled_previous_pipeline_head) * 32 *
1358                         HZ / (jiffies - tape->controlled_previous_head_time);
1359
1360         if (tape->nr_pending_stages < tape->max_stages/*- 1 */) {
1361                 /* -1 for read mode error recovery */
1362                 if (time_after(jiffies, tape->uncontrolled_previous_head_time +
1363                                         10 * HZ)) {
1364                         tape->uncontrolled_pipeline_head_time = jiffies;
1365                         tape->uncontrolled_pipeline_head_speed =
1366                                 (tape->pipeline_head -
1367                                  tape->uncontrolled_previous_pipeline_head) *
1368                                 32 * HZ / (jiffies -
1369                                         tape->uncontrolled_previous_head_time);
1370                 }
1371         } else {
1372                 tape->uncontrolled_previous_head_time = jiffies;
1373                 tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
1374                 if (time_after(jiffies, tape->uncontrolled_pipeline_head_time +
1375                                         30 * HZ))
1376                         tape->uncontrolled_pipeline_head_time = jiffies;
1377
1378         }
1379         tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed,
1380                                         tape->controlled_pipeline_head_speed);
1381
1382         if (tape->speed_control == 1) {
1383                 if (tape->nr_pending_stages >= tape->max_stages / 2)
1384                         tape->max_insert_speed = tape->pipeline_head_speed +
1385                                 (1100 - tape->pipeline_head_speed) * 2 *
1386                                 (tape->nr_pending_stages - tape->max_stages / 2)
1387                                 / tape->max_stages;
1388                 else
1389                         tape->max_insert_speed = 500 +
1390                                 (tape->pipeline_head_speed - 500) * 2 *
1391                                 tape->nr_pending_stages / tape->max_stages;
1392
1393                 if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
1394                         tape->max_insert_speed = 5000;
1395         } else
1396                 tape->max_insert_speed = tape->speed_control;
1397
1398         tape->max_insert_speed = max(tape->max_insert_speed, 500);
1399 }
1400
1401 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
1402 {
1403         idetape_tape_t *tape = drive->driver_data;
1404         struct ide_atapi_pc *pc = tape->pc;
1405         u8 stat;
1406
1407         stat = ide_read_status(drive);
1408
1409         if (stat & SEEK_STAT) {
1410                 if (stat & ERR_STAT) {
1411                         /* Error detected */
1412                         if (pc->c[0] != TEST_UNIT_READY)
1413                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
1414                                                 tape->name);
1415                         /* Retry operation */
1416                         return idetape_retry_pc(drive);
1417                 }
1418                 pc->error = 0;
1419                 if (tape->failed_pc == pc)
1420                         tape->failed_pc = NULL;
1421         } else {
1422                 pc->error = IDETAPE_ERROR_GENERAL;
1423                 tape->failed_pc = NULL;
1424         }
1425         return pc->idetape_callback(drive);
1426 }
1427
1428 static ide_startstop_t idetape_rw_callback(ide_drive_t *drive)
1429 {
1430         idetape_tape_t *tape = drive->driver_data;
1431         struct request *rq = HWGROUP(drive)->rq;
1432         int blocks = tape->pc->xferred / tape->blk_size;
1433
1434         tape->avg_size += blocks * tape->blk_size;
1435         tape->insert_size += blocks * tape->blk_size;
1436         if (tape->insert_size > 1024 * 1024)
1437                 tape->measure_insert_time = 1;
1438         if (tape->measure_insert_time) {
1439                 tape->measure_insert_time = 0;
1440                 tape->insert_time = jiffies;
1441                 tape->insert_size = 0;
1442         }
1443         if (time_after(jiffies, tape->insert_time))
1444                 tape->insert_speed = tape->insert_size / 1024 * HZ /
1445                                         (jiffies - tape->insert_time);
1446         if (time_after_eq(jiffies, tape->avg_time + HZ)) {
1447                 tape->avg_speed = tape->avg_size * HZ /
1448                                 (jiffies - tape->avg_time) / 1024;
1449                 tape->avg_size = 0;
1450                 tape->avg_time = jiffies;
1451         }
1452         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1453
1454         tape->first_frame += blocks;
1455         rq->current_nr_sectors -= blocks;
1456
1457         if (!tape->pc->error)
1458                 idetape_end_request(drive, 1, 0);
1459         else
1460                 idetape_end_request(drive, tape->pc->error, 0);
1461         return ide_stopped;
1462 }
1463
1464 static void idetape_create_read_cmd(idetape_tape_t *tape,
1465                 struct ide_atapi_pc *pc,
1466                 unsigned int length, struct idetape_bh *bh)
1467 {
1468         idetape_init_pc(pc);
1469         pc->c[0] = READ_6;
1470         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1471         pc->c[1] = 1;
1472         pc->idetape_callback = &idetape_rw_callback;
1473         pc->bh = bh;
1474         atomic_set(&bh->b_count, 0);
1475         pc->buf = NULL;
1476         pc->buf_size = length * tape->blk_size;
1477         pc->req_xfer = pc->buf_size;
1478         if (pc->req_xfer == tape->stage_size)
1479                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1480 }
1481
1482 static void idetape_create_write_cmd(idetape_tape_t *tape,
1483                 struct ide_atapi_pc *pc,
1484                 unsigned int length, struct idetape_bh *bh)
1485 {
1486         idetape_init_pc(pc);
1487         pc->c[0] = WRITE_6;
1488         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1489         pc->c[1] = 1;
1490         pc->idetape_callback = &idetape_rw_callback;
1491         pc->flags |= PC_FLAG_WRITING;
1492         pc->bh = bh;
1493         pc->b_data = bh->b_data;
1494         pc->b_count = atomic_read(&bh->b_count);
1495         pc->buf = NULL;
1496         pc->buf_size = length * tape->blk_size;
1497         pc->req_xfer = pc->buf_size;
1498         if (pc->req_xfer == tape->stage_size)
1499                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1500 }
1501
1502 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1503                                           struct request *rq, sector_t block)
1504 {
1505         idetape_tape_t *tape = drive->driver_data;
1506         struct ide_atapi_pc *pc = NULL;
1507         struct request *postponed_rq = tape->postponed_rq;
1508         u8 stat;
1509
1510         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
1511                         " current_nr_sectors: %d\n",
1512                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1513
1514         if (!blk_special_request(rq)) {
1515                 /* We do not support buffer cache originated requests. */
1516                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1517                         "request queue (%d)\n", drive->name, rq->cmd_type);
1518                 ide_end_request(drive, 0, 0);
1519                 return ide_stopped;
1520         }
1521
1522         /* Retry a failed packet command */
1523         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE)
1524                 return idetape_issue_pc(drive, tape->failed_pc);
1525
1526         if (postponed_rq != NULL)
1527                 if (rq != postponed_rq) {
1528                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1529                                         "Two DSC requests were queued\n");
1530                         idetape_end_request(drive, 0, 0);
1531                         return ide_stopped;
1532                 }
1533
1534         tape->postponed_rq = NULL;
1535
1536         /*
1537          * If the tape is still busy, postpone our request and service
1538          * the other device meanwhile.
1539          */
1540         stat = ide_read_status(drive);
1541
1542         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
1543                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1544
1545         if (drive->post_reset == 1) {
1546                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1547                 drive->post_reset = 0;
1548         }
1549
1550         if (time_after(jiffies, tape->insert_time))
1551                 tape->insert_speed = tape->insert_size / 1024 * HZ /
1552                                         (jiffies - tape->insert_time);
1553         idetape_calculate_speeds(drive);
1554         if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&
1555             (stat & SEEK_STAT) == 0) {
1556                 if (postponed_rq == NULL) {
1557                         tape->dsc_polling_start = jiffies;
1558                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1559                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1560                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1561                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1562                                 tape->name);
1563                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1564                                 idetape_media_access_finished(drive);
1565                                 return ide_stopped;
1566                         } else {
1567                                 return ide_do_reset(drive);
1568                         }
1569                 } else if (time_after(jiffies,
1570                                         tape->dsc_polling_start +
1571                                         IDETAPE_DSC_MA_THRESHOLD))
1572                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1573                 idetape_postpone_request(drive);
1574                 return ide_stopped;
1575         }
1576         if (rq->cmd[0] & REQ_IDETAPE_READ) {
1577                 tape->buffer_head++;
1578                 tape->postpone_cnt = 0;
1579                 pc = idetape_next_pc_storage(drive);
1580                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
1581                                         (struct idetape_bh *)rq->special);
1582                 goto out;
1583         }
1584         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1585                 tape->buffer_head++;
1586                 tape->postpone_cnt = 0;
1587                 pc = idetape_next_pc_storage(drive);
1588                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
1589                                          (struct idetape_bh *)rq->special);
1590                 goto out;
1591         }
1592         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
1593                 pc = (struct ide_atapi_pc *) rq->buffer;
1594                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
1595                 rq->cmd[0] |= REQ_IDETAPE_PC2;
1596                 goto out;
1597         }
1598         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1599                 idetape_media_access_finished(drive);
1600                 return ide_stopped;
1601         }
1602         BUG();
1603 out:
1604         return idetape_issue_pc(drive, pc);
1605 }
1606
1607 /* Pipeline related functions */
1608 static inline int idetape_pipeline_active(idetape_tape_t *tape)
1609 {
1610         int rc1, rc2;
1611
1612         rc1 = test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
1613         rc2 = (tape->active_data_rq != NULL);
1614         return rc1;
1615 }
1616
1617 /*
1618  * The function below uses __get_free_page to allocate a pipeline stage, along
1619  * with all the necessary small buffers which together make a buffer of size
1620  * tape->stage_size (or a bit more). We attempt to combine sequential pages as
1621  * much as possible.
1622  *
1623  * It returns a pointer to the new allocated stage, or NULL if we can't (or
1624  * don't want to) allocate a stage.
1625  *
1626  * Pipeline stages are optional and are used to increase performance. If we
1627  * can't allocate them, we'll manage without them.
1628  */
1629 static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,
1630                                                 int clear)
1631 {
1632         idetape_stage_t *stage;
1633         struct idetape_bh *prev_bh, *bh;
1634         int pages = tape->pages_per_stage;
1635         char *b_data = NULL;
1636
1637         stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
1638         if (!stage)
1639                 return NULL;
1640         stage->next = NULL;
1641
1642         stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1643         bh = stage->bh;
1644         if (bh == NULL)
1645                 goto abort;
1646         bh->b_reqnext = NULL;
1647         bh->b_data = (char *) __get_free_page(GFP_KERNEL);
1648         if (!bh->b_data)
1649                 goto abort;
1650         if (clear)
1651                 memset(bh->b_data, 0, PAGE_SIZE);
1652         bh->b_size = PAGE_SIZE;
1653         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1654
1655         while (--pages) {
1656                 b_data = (char *) __get_free_page(GFP_KERNEL);
1657                 if (!b_data)
1658                         goto abort;
1659                 if (clear)
1660                         memset(b_data, 0, PAGE_SIZE);
1661                 if (bh->b_data == b_data + PAGE_SIZE) {
1662                         bh->b_size += PAGE_SIZE;
1663                         bh->b_data -= PAGE_SIZE;
1664                         if (full)
1665                                 atomic_add(PAGE_SIZE, &bh->b_count);
1666                         continue;
1667                 }
1668                 if (b_data == bh->b_data + bh->b_size) {
1669                         bh->b_size += PAGE_SIZE;
1670                         if (full)
1671                                 atomic_add(PAGE_SIZE, &bh->b_count);
1672                         continue;
1673                 }
1674                 prev_bh = bh;
1675                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1676                 if (!bh) {
1677                         free_page((unsigned long) b_data);
1678                         goto abort;
1679                 }
1680                 bh->b_reqnext = NULL;
1681                 bh->b_data = b_data;
1682                 bh->b_size = PAGE_SIZE;
1683                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1684                 prev_bh->b_reqnext = bh;
1685         }
1686         bh->b_size -= tape->excess_bh_size;
1687         if (full)
1688                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1689         return stage;
1690 abort:
1691         __idetape_kfree_stage(stage);
1692         return NULL;
1693 }
1694
1695 static idetape_stage_t *idetape_kmalloc_stage(idetape_tape_t *tape)
1696 {
1697         idetape_stage_t *cache_stage = tape->cache_stage;
1698
1699         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1700
1701         if (tape->nr_stages >= tape->max_stages)
1702                 return NULL;
1703         if (cache_stage != NULL) {
1704                 tape->cache_stage = NULL;
1705                 return cache_stage;
1706         }
1707         return __idetape_kmalloc_stage(tape, 0, 0);
1708 }
1709
1710 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1711                 idetape_stage_t *stage, const char __user *buf, int n)
1712 {
1713         struct idetape_bh *bh = tape->bh;
1714         int count;
1715         int ret = 0;
1716
1717         while (n) {
1718                 if (bh == NULL) {
1719                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1720                                         __func__);
1721                         return 1;
1722                 }
1723                 count = min((unsigned int)
1724                                 (bh->b_size - atomic_read(&bh->b_count)),
1725                                 (unsigned int)n);
1726                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1727                                 count))
1728                         ret = 1;
1729                 n -= count;
1730                 atomic_add(count, &bh->b_count);
1731                 buf += count;
1732                 if (atomic_read(&bh->b_count) == bh->b_size) {
1733                         bh = bh->b_reqnext;
1734                         if (bh)
1735                                 atomic_set(&bh->b_count, 0);
1736                 }
1737         }
1738         tape->bh = bh;
1739         return ret;
1740 }
1741
1742 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1743                 idetape_stage_t *stage, int n)
1744 {
1745         struct idetape_bh *bh = tape->bh;
1746         int count;
1747         int ret = 0;
1748
1749         while (n) {
1750                 if (bh == NULL) {
1751                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1752                                         __func__);
1753                         return 1;
1754                 }
1755                 count = min(tape->b_count, n);
1756                 if  (copy_to_user(buf, tape->b_data, count))
1757                         ret = 1;
1758                 n -= count;
1759                 tape->b_data += count;
1760                 tape->b_count -= count;
1761                 buf += count;
1762                 if (!tape->b_count) {
1763                         bh = bh->b_reqnext;
1764                         tape->bh = bh;
1765                         if (bh) {
1766                                 tape->b_data = bh->b_data;
1767                                 tape->b_count = atomic_read(&bh->b_count);
1768                         }
1769                 }
1770         }
1771         return ret;
1772 }
1773
1774 static void idetape_init_merge_stage(idetape_tape_t *tape)
1775 {
1776         struct idetape_bh *bh = tape->merge_stage->bh;
1777
1778         tape->bh = bh;
1779         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1780                 atomic_set(&bh->b_count, 0);
1781         else {
1782                 tape->b_data = bh->b_data;
1783                 tape->b_count = atomic_read(&bh->b_count);
1784         }
1785 }
1786
1787 static void idetape_switch_buffers(idetape_tape_t *tape, idetape_stage_t *stage)
1788 {
1789         struct idetape_bh *tmp;
1790
1791         tmp = stage->bh;
1792         stage->bh = tape->merge_stage->bh;
1793         tape->merge_stage->bh = tmp;
1794         idetape_init_merge_stage(tape);
1795 }
1796
1797 /* Add a new stage at the end of the pipeline. */
1798 static void idetape_add_stage_tail(ide_drive_t *drive, idetape_stage_t *stage)
1799 {
1800         idetape_tape_t *tape = drive->driver_data;
1801         unsigned long flags;
1802
1803         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1804
1805         spin_lock_irqsave(&tape->lock, flags);
1806         stage->next = NULL;
1807         if (tape->last_stage != NULL)
1808                 tape->last_stage->next = stage;
1809         else
1810                 tape->first_stage = stage;
1811                 tape->next_stage  = stage;
1812         tape->last_stage = stage;
1813         if (tape->next_stage == NULL)
1814                 tape->next_stage = tape->last_stage;
1815         tape->nr_stages++;
1816         tape->nr_pending_stages++;
1817         spin_unlock_irqrestore(&tape->lock, flags);
1818 }
1819
1820 /* Install a completion in a pending request and sleep until it is serviced. The
1821  * caller should ensure that the request will not be serviced before we install
1822  * the completion (usually by disabling interrupts).
1823  */
1824 static void idetape_wait_for_request(ide_drive_t *drive, struct request *rq)
1825 {
1826         DECLARE_COMPLETION_ONSTACK(wait);
1827         idetape_tape_t *tape = drive->driver_data;
1828
1829         if (rq == NULL || !blk_special_request(rq)) {
1830                 printk(KERN_ERR "ide-tape: bug: Trying to sleep on non-valid"
1831                                  " request\n");
1832                 return;
1833         }
1834         rq->end_io_data = &wait;
1835         rq->end_io = blk_end_sync_rq;
1836         spin_unlock_irq(&tape->lock);
1837         wait_for_completion(&wait);
1838         /* The stage and its struct request have been deallocated */
1839         spin_lock_irq(&tape->lock);
1840 }
1841
1842 static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
1843 {
1844         idetape_tape_t *tape = drive->driver_data;
1845         u8 *readpos = tape->pc->buf;
1846
1847         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1848
1849         if (!tape->pc->error) {
1850                 debug_log(DBG_SENSE, "BOP - %s\n",
1851                                 (readpos[0] & 0x80) ? "Yes" : "No");
1852                 debug_log(DBG_SENSE, "EOP - %s\n",
1853                                 (readpos[0] & 0x40) ? "Yes" : "No");
1854
1855                 if (readpos[0] & 0x4) {
1856                         printk(KERN_INFO "ide-tape: Block location is unknown"
1857                                          "to the tape\n");
1858                         clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
1859                         idetape_end_request(drive, 0, 0);
1860                 } else {
1861                         debug_log(DBG_SENSE, "Block Location - %u\n",
1862                                         be32_to_cpu(*(u32 *)&readpos[4]));
1863
1864                         tape->partition = readpos[1];
1865                         tape->first_frame =
1866                                 be32_to_cpu(*(u32 *)&readpos[4]);
1867                         set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
1868                         idetape_end_request(drive, 1, 0);
1869                 }
1870         } else {
1871                 idetape_end_request(drive, 0, 0);
1872         }
1873         return ide_stopped;
1874 }
1875
1876 /*
1877  * Write a filemark if write_filemark=1. Flush the device buffers without
1878  * writing a filemark otherwise.
1879  */
1880 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1881                 struct ide_atapi_pc *pc, int write_filemark)
1882 {
1883         idetape_init_pc(pc);
1884         pc->c[0] = WRITE_FILEMARKS;
1885         pc->c[4] = write_filemark;
1886         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1887         pc->idetape_callback = &idetape_pc_callback;
1888 }
1889
1890 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1891 {
1892         idetape_init_pc(pc);
1893         pc->c[0] = TEST_UNIT_READY;
1894         pc->idetape_callback = &idetape_pc_callback;
1895 }
1896
1897 /*
1898  * We add a special packet command request to the tail of the request queue, and
1899  * wait for it to be serviced. This is not to be called from within the request
1900  * handling part of the driver! We allocate here data on the stack and it is
1901  * valid until the request is finished. This is not the case for the bottom part
1902  * of the driver, where we are always leaving the functions to wait for an
1903  * interrupt or a timer event.
1904  *
1905  * From the bottom part of the driver, we should allocate safe memory using
1906  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1907  * to the request list without waiting for it to be serviced! In that case, we
1908  * usually use idetape_queue_pc_head().
1909  */
1910 static int __idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1911 {
1912         struct ide_tape_obj *tape = drive->driver_data;
1913         struct request rq;
1914
1915         idetape_init_rq(&rq, REQ_IDETAPE_PC1);
1916         rq.buffer = (char *) pc;
1917         rq.rq_disk = tape->disk;
1918         return ide_do_drive_cmd(drive, &rq, ide_wait);
1919 }
1920
1921 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1922                 struct ide_atapi_pc *pc, int cmd)
1923 {
1924         idetape_init_pc(pc);
1925         pc->c[0] = START_STOP;
1926         pc->c[4] = cmd;
1927         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1928         pc->idetape_callback = &idetape_pc_callback;
1929 }
1930
1931 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1932 {
1933         idetape_tape_t *tape = drive->driver_data;
1934         struct ide_atapi_pc pc;
1935         int load_attempted = 0;
1936
1937         /* Wait for the tape to become ready */
1938         set_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
1939         timeout += jiffies;
1940         while (time_before(jiffies, timeout)) {
1941                 idetape_create_test_unit_ready_cmd(&pc);
1942                 if (!__idetape_queue_pc_tail(drive, &pc))
1943                         return 0;
1944                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1945                     || (tape->asc == 0x3A)) {
1946                         /* no media */
1947                         if (load_attempted)
1948                                 return -ENOMEDIUM;
1949                         idetape_create_load_unload_cmd(drive, &pc,
1950                                                         IDETAPE_LU_LOAD_MASK);
1951                         __idetape_queue_pc_tail(drive, &pc);
1952                         load_attempted = 1;
1953                 /* not about to be ready */
1954                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1955                              (tape->ascq == 1 || tape->ascq == 8)))
1956                         return -EIO;
1957                 msleep(100);
1958         }
1959         return -EIO;
1960 }
1961
1962 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1963 {
1964         return __idetape_queue_pc_tail(drive, pc);
1965 }
1966
1967 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1968 {
1969         struct ide_atapi_pc pc;
1970         int rc;
1971
1972         idetape_create_write_filemark_cmd(drive, &pc, 0);
1973         rc = idetape_queue_pc_tail(drive, &pc);
1974         if (rc)
1975                 return rc;
1976         idetape_wait_ready(drive, 60 * 5 * HZ);
1977         return 0;
1978 }
1979
1980 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1981 {
1982         idetape_init_pc(pc);
1983         pc->c[0] = READ_POSITION;
1984         pc->req_xfer = 20;
1985         pc->idetape_callback = &idetape_read_position_callback;
1986 }
1987
1988 static int idetape_read_position(ide_drive_t *drive)
1989 {
1990         idetape_tape_t *tape = drive->driver_data;
1991         struct ide_atapi_pc pc;
1992         int position;
1993
1994         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1995
1996         idetape_create_read_position_cmd(&pc);
1997         if (idetape_queue_pc_tail(drive, &pc))
1998                 return -1;
1999         position = tape->first_frame;
2000         return position;
2001 }
2002
2003 static void idetape_create_locate_cmd(ide_drive_t *drive,
2004                 struct ide_atapi_pc *pc,
2005                 unsigned int block, u8 partition, int skip)
2006 {
2007         idetape_init_pc(pc);
2008         pc->c[0] = POSITION_TO_ELEMENT;
2009         pc->c[1] = 2;
2010         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
2011         pc->c[8] = partition;
2012         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2013         pc->idetape_callback = &idetape_pc_callback;
2014 }
2015
2016 static int idetape_create_prevent_cmd(ide_drive_t *drive,
2017                 struct ide_atapi_pc *pc, int prevent)
2018 {
2019         idetape_tape_t *tape = drive->driver_data;
2020
2021         /* device supports locking according to capabilities page */
2022         if (!(tape->caps[6] & 0x01))
2023                 return 0;
2024
2025         idetape_init_pc(pc);
2026         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
2027         pc->c[4] = prevent;
2028         pc->idetape_callback = &idetape_pc_callback;
2029         return 1;
2030 }
2031
2032 static int __idetape_discard_read_pipeline(ide_drive_t *drive)
2033 {
2034         idetape_tape_t *tape = drive->driver_data;
2035         unsigned long flags;
2036         int cnt;
2037
2038         if (tape->chrdev_dir != IDETAPE_DIR_READ)
2039                 return 0;
2040
2041         /* Remove merge stage. */
2042         cnt = tape->merge_stage_size / tape->blk_size;
2043         if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
2044                 ++cnt;          /* Filemarks count as 1 sector */
2045         tape->merge_stage_size = 0;
2046         if (tape->merge_stage != NULL) {
2047                 __idetape_kfree_stage(tape->merge_stage);
2048                 tape->merge_stage = NULL;
2049         }
2050
2051         /* Clear pipeline flags. */
2052         clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
2053         tape->chrdev_dir = IDETAPE_DIR_NONE;
2054
2055         /* Remove pipeline stages. */
2056         if (tape->first_stage == NULL)
2057                 return 0;
2058
2059         spin_lock_irqsave(&tape->lock, flags);
2060         tape->next_stage = NULL;
2061         if (idetape_pipeline_active(tape))
2062                 idetape_wait_for_request(drive, tape->active_data_rq);
2063         spin_unlock_irqrestore(&tape->lock, flags);
2064
2065         while (tape->first_stage != NULL) {
2066                 struct request *rq_ptr = &tape->first_stage->rq;
2067
2068                 cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors;
2069                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
2070                         ++cnt;
2071                 idetape_remove_stage_head(drive);
2072         }
2073         tape->nr_pending_stages = 0;
2074         tape->max_stages = tape->min_pipeline;
2075         return cnt;
2076 }
2077
2078 /*
2079  * Position the tape to the requested block using the LOCATE packet command.
2080  * A READ POSITION command is then issued to check where we are positioned. Like
2081  * all higher level operations, we queue the commands at the tail of the request
2082  * queue and wait for their completion.
2083  */
2084 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
2085                 u8 partition, int skip)
2086 {
2087         idetape_tape_t *tape = drive->driver_data;
2088         int retval;
2089         struct ide_atapi_pc pc;
2090
2091         if (tape->chrdev_dir == IDETAPE_DIR_READ)
2092                 __idetape_discard_read_pipeline(drive);
2093         idetape_wait_ready(drive, 60 * 5 * HZ);
2094         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
2095         retval = idetape_queue_pc_tail(drive, &pc);
2096         if (retval)
2097                 return (retval);
2098
2099         idetape_create_read_position_cmd(&pc);
2100         return (idetape_queue_pc_tail(drive, &pc));
2101 }
2102
2103 static void idetape_discard_read_pipeline(ide_drive_t *drive,
2104                                           int restore_position)
2105 {
2106         idetape_tape_t *tape = drive->driver_data;
2107         int cnt;
2108         int seek, position;
2109
2110         cnt = __idetape_discard_read_pipeline(drive);
2111         if (restore_position) {
2112                 position = idetape_read_position(drive);
2113                 seek = position > cnt ? position - cnt : 0;
2114                 if (idetape_position_tape(drive, seek, 0, 0)) {
2115                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
2116                                          " discard_pipeline()\n", tape->name);
2117                         return;
2118                 }
2119         }
2120 }
2121
2122 /*
2123  * Generate a read/write request for the block device interface and wait for it
2124  * to be serviced.
2125  */
2126 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
2127                                  struct idetape_bh *bh)
2128 {
2129         idetape_tape_t *tape = drive->driver_data;
2130         struct request rq;
2131
2132         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
2133
2134         if (idetape_pipeline_active(tape)) {
2135                 printk(KERN_ERR "ide-tape: bug: the pipeline is active in %s\n",
2136                                 __func__);
2137                 return (0);
2138         }
2139
2140         idetape_init_rq(&rq, cmd);
2141         rq.rq_disk = tape->disk;
2142         rq.special = (void *)bh;
2143         rq.sector = tape->first_frame;
2144         rq.nr_sectors           = blocks;
2145         rq.current_nr_sectors   = blocks;
2146         (void) ide_do_drive_cmd(drive, &rq, ide_wait);
2147
2148         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
2149                 return 0;
2150
2151         if (tape->merge_stage)
2152                 idetape_init_merge_stage(tape);
2153         if (rq.errors == IDETAPE_ERROR_GENERAL)
2154                 return -EIO;
2155         return (tape->blk_size * (blocks-rq.current_nr_sectors));
2156 }
2157
2158 /* start servicing the pipeline stages, starting from tape->next_stage. */
2159 static void idetape_plug_pipeline(ide_drive_t *drive)
2160 {
2161         idetape_tape_t *tape = drive->driver_data;
2162
2163         if (tape->next_stage == NULL)
2164                 return;
2165         if (!idetape_pipeline_active(tape)) {
2166                 set_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
2167                 idetape_activate_next_stage(drive);
2168                 (void) ide_do_drive_cmd(drive, tape->active_data_rq, ide_end);
2169         }
2170 }
2171
2172 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
2173 {
2174         idetape_init_pc(pc);
2175         pc->c[0] = INQUIRY;
2176         pc->c[4] = 254;
2177         pc->req_xfer = 254;
2178         pc->idetape_callback = &idetape_pc_callback;
2179 }
2180
2181 static void idetape_create_rewind_cmd(ide_drive_t *drive,
2182                 struct ide_atapi_pc *pc)
2183 {
2184         idetape_init_pc(pc);
2185         pc->c[0] = REZERO_UNIT;
2186         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2187         pc->idetape_callback = &idetape_pc_callback;
2188 }
2189
2190 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
2191 {
2192         idetape_init_pc(pc);
2193         pc->c[0] = ERASE;
2194         pc->c[1] = 1;
2195         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2196         pc->idetape_callback = &idetape_pc_callback;
2197 }
2198
2199 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
2200 {
2201         idetape_init_pc(pc);
2202         pc->c[0] = SPACE;
2203         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
2204         pc->c[1] = cmd;
2205         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2206         pc->idetape_callback = &idetape_pc_callback;
2207 }
2208
2209 static void idetape_wait_first_stage(ide_drive_t *drive)
2210 {
2211         idetape_tape_t *tape = drive->driver_data;
2212         unsigned long flags;
2213
2214         if (tape->first_stage == NULL)
2215                 return;
2216         spin_lock_irqsave(&tape->lock, flags);
2217         if (tape->active_stage == tape->first_stage)
2218                 idetape_wait_for_request(drive, tape->active_data_rq);
2219         spin_unlock_irqrestore(&tape->lock, flags);
2220 }
2221
2222 /*
2223  * Try to add a character device originated write request to our pipeline. In
2224  * case we don't succeed, we revert to non-pipelined operation mode for this
2225  * request. In order to accomplish that, we
2226  *
2227  * 1. Try to allocate a new pipeline stage.
2228  * 2. If we can't, wait for more and more requests to be serviced and try again
2229  * each time.
2230  * 3. If we still can't allocate a stage, fallback to non-pipelined operation
2231  * mode for this request.
2232  */
2233 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
2234 {
2235         idetape_tape_t *tape = drive->driver_data;
2236         idetape_stage_t *new_stage;
2237         unsigned long flags;
2238         struct request *rq;
2239
2240         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2241
2242         /* Attempt to allocate a new stage. Beware possible race conditions. */
2243         while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
2244                 spin_lock_irqsave(&tape->lock, flags);
2245                 if (idetape_pipeline_active(tape)) {
2246                         idetape_wait_for_request(drive, tape->active_data_rq);
2247                         spin_unlock_irqrestore(&tape->lock, flags);
2248                 } else {
2249                         spin_unlock_irqrestore(&tape->lock, flags);
2250                         idetape_plug_pipeline(drive);
2251                         if (idetape_pipeline_active(tape))
2252                                 continue;
2253                         /*
2254                          * The machine is short on memory. Fallback to non-
2255                          * pipelined operation mode for this request.
2256                          */
2257                         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
2258                                                 blocks, tape->merge_stage->bh);
2259                 }
2260         }
2261         rq = &new_stage->rq;
2262         idetape_init_rq(rq, REQ_IDETAPE_WRITE);
2263         /* Doesn't actually matter - We always assume sequential access */
2264         rq->sector = tape->first_frame;
2265         rq->current_nr_sectors = blocks;
2266         rq->nr_sectors = blocks;
2267
2268         idetape_switch_buffers(tape, new_stage);
2269         idetape_add_stage_tail(drive, new_stage);
2270         tape->pipeline_head++;
2271         idetape_calculate_speeds(drive);
2272
2273         /*
2274          * Estimate whether the tape has stopped writing by checking if our
2275          * write pipeline is currently empty. If we are not writing anymore,
2276          * wait for the pipeline to be almost completely full (90%) before
2277          * starting to service requests, so that we will be able to keep up with
2278          * the higher speeds of the tape.
2279          */
2280         if (!idetape_pipeline_active(tape)) {
2281                 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
2282                         tape->nr_stages >= tape->max_stages -
2283                         tape->uncontrolled_pipeline_head_speed * 3 * 1024 /
2284                         tape->blk_size) {
2285                         tape->measure_insert_time = 1;
2286                         tape->insert_time = jiffies;
2287                         tape->insert_size = 0;
2288                         tape->insert_speed = 0;
2289                         idetape_plug_pipeline(drive);
2290                 }
2291         }
2292         if (test_and_clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
2293                 /* Return a deferred error */
2294                 return -EIO;
2295         return blocks;
2296 }
2297
2298 /*
2299  * Wait until all pending pipeline requests are serviced. Typically called on
2300  * device close.
2301  */
2302 static void idetape_wait_for_pipeline(ide_drive_t *drive)
2303 {
2304         idetape_tape_t *tape = drive->driver_data;
2305         unsigned long flags;
2306
2307         while (tape->next_stage || idetape_pipeline_active(tape)) {
2308                 idetape_plug_pipeline(drive);
2309                 spin_lock_irqsave(&tape->lock, flags);
2310                 if (idetape_pipeline_active(tape))
2311                         idetape_wait_for_request(drive, tape->active_data_rq);
2312                 spin_unlock_irqrestore(&tape->lock, flags);
2313         }
2314 }
2315
2316 static void idetape_empty_write_pipeline(ide_drive_t *drive)
2317 {
2318         idetape_tape_t *tape = drive->driver_data;
2319         int blocks, min;
2320         struct idetape_bh *bh;
2321
2322         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2323                 printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline,"
2324                                 " but we are not writing.\n");
2325                 return;
2326         }
2327         if (tape->merge_stage_size > tape->stage_size) {
2328                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
2329                 tape->merge_stage_size = tape->stage_size;
2330         }
2331         if (tape->merge_stage_size) {
2332                 blocks = tape->merge_stage_size / tape->blk_size;
2333                 if (tape->merge_stage_size % tape->blk_size) {
2334                         unsigned int i;
2335
2336                         blocks++;
2337                         i = tape->blk_size - tape->merge_stage_size %
2338                                 tape->blk_size;
2339                         bh = tape->bh->b_reqnext;
2340                         while (bh) {
2341                                 atomic_set(&bh->b_count, 0);
2342                                 bh = bh->b_reqnext;
2343                         }
2344                         bh = tape->bh;
2345                         while (i) {
2346                                 if (bh == NULL) {
2347                                         printk(KERN_INFO "ide-tape: bug,"
2348                                                          " bh NULL\n");
2349                                         break;
2350                                 }
2351                                 min = min(i, (unsigned int)(bh->b_size -
2352                                                 atomic_read(&bh->b_count)));
2353                                 memset(bh->b_data + atomic_read(&bh->b_count),
2354                                                 0, min);
2355                                 atomic_add(min, &bh->b_count);
2356                                 i -= min;
2357                                 bh = bh->b_reqnext;
2358                         }
2359                 }
2360                 (void) idetape_add_chrdev_write_request(drive, blocks);
2361                 tape->merge_stage_size = 0;
2362         }
2363         idetape_wait_for_pipeline(drive);
2364         if (tape->merge_stage != NULL) {
2365                 __idetape_kfree_stage(tape->merge_stage);
2366                 tape->merge_stage = NULL;
2367         }
2368         clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
2369         tape->chrdev_dir = IDETAPE_DIR_NONE;
2370
2371         /*
2372          * On the next backup, perform the feedback loop again. (I don't want to
2373          * keep sense information between backups, as some systems are
2374          * constantly on, and the system load can be totally different on the
2375          * next backup).
2376          */
2377         tape->max_stages = tape->min_pipeline;
2378         if (tape->first_stage != NULL ||
2379             tape->next_stage != NULL ||
2380             tape->last_stage != NULL ||
2381             tape->nr_stages != 0) {
2382                 printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
2383                         "first_stage %p, next_stage %p, "
2384                         "last_stage %p, nr_stages %d\n",
2385                         tape->first_stage, tape->next_stage,
2386                         tape->last_stage, tape->nr_stages);
2387         }
2388 }
2389
2390 static void idetape_restart_speed_control(ide_drive_t *drive)
2391 {
2392         idetape_tape_t *tape = drive->driver_data;
2393
2394         tape->restart_speed_control_req = 0;
2395         tape->pipeline_head = 0;
2396         tape->controlled_last_pipeline_head = 0;
2397         tape->controlled_previous_pipeline_head = 0;
2398         tape->uncontrolled_previous_pipeline_head = 0;
2399         tape->controlled_pipeline_head_speed = 5000;
2400         tape->pipeline_head_speed = 5000;
2401         tape->uncontrolled_pipeline_head_speed = 0;
2402         tape->controlled_pipeline_head_time =
2403                 tape->uncontrolled_pipeline_head_time = jiffies;
2404         tape->controlled_previous_head_time =
2405                 tape->uncontrolled_previous_head_time = jiffies;
2406 }
2407
2408 static int idetape_init_read(ide_drive_t *drive, int max_stages)
2409 {
2410         idetape_tape_t *tape = drive->driver_data;
2411         idetape_stage_t *new_stage;
2412         struct request rq;
2413         int bytes_read;
2414         u16 blocks = *(u16 *)&tape->caps[12];
2415
2416         /* Initialize read operation */
2417         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
2418                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2419                         idetape_empty_write_pipeline(drive);
2420                         idetape_flush_tape_buffers(drive);
2421                 }
2422                 if (tape->merge_stage || tape->merge_stage_size) {
2423                         printk(KERN_ERR "ide-tape: merge_stage_size should be"
2424                                          " 0 now\n");
2425                         tape->merge_stage_size = 0;
2426                 }
2427                 tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
2428                 if (!tape->merge_stage)
2429                         return -ENOMEM;
2430                 tape->chrdev_dir = IDETAPE_DIR_READ;
2431
2432                 /*
2433                  * Issue a read 0 command to ensure that DSC handshake is
2434                  * switched from completion mode to buffer available mode.
2435                  * No point in issuing this if DSC overlap isn't supported, some
2436                  * drives (Seagate STT3401A) will return an error.
2437                  */
2438                 if (drive->dsc_overlap) {
2439                         bytes_read = idetape_queue_rw_tail(drive,
2440                                                         REQ_IDETAPE_READ, 0,
2441                                                         tape->merge_stage->bh);
2442                         if (bytes_read < 0) {
2443                                 __idetape_kfree_stage(tape->merge_stage);
2444                                 tape->merge_stage = NULL;
2445                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2446                                 return bytes_read;
2447                         }
2448                 }
2449         }
2450         if (tape->restart_speed_control_req)
2451                 idetape_restart_speed_control(drive);
2452         idetape_init_rq(&rq, REQ_IDETAPE_READ);
2453         rq.sector = tape->first_frame;
2454         rq.nr_sectors = blocks;
2455         rq.current_nr_sectors = blocks;
2456         if (!test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags) &&
2457             tape->nr_stages < max_stages) {
2458                 new_stage = idetape_kmalloc_stage(tape);
2459                 while (new_stage != NULL) {
2460                         new_stage->rq = rq;
2461                         idetape_add_stage_tail(drive, new_stage);
2462                         if (tape->nr_stages >= max_stages)
2463                                 break;
2464                         new_stage = idetape_kmalloc_stage(tape);
2465                 }
2466         }
2467         if (!idetape_pipeline_active(tape)) {
2468                 if (tape->nr_pending_stages >= 3 * max_stages / 4) {
2469                         tape->measure_insert_time = 1;
2470                         tape->insert_time = jiffies;
2471                         tape->insert_size = 0;
2472                         tape->insert_speed = 0;
2473                         idetape_plug_pipeline(drive);
2474                 }
2475         }
2476         return 0;
2477 }
2478
2479 /*
2480  * Called from idetape_chrdev_read() to service a character device read request
2481  * and add read-ahead requests to our pipeline.
2482  */
2483 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
2484 {
2485         idetape_tape_t *tape = drive->driver_data;
2486         unsigned long flags;
2487         struct request *rq_ptr;
2488         int bytes_read;
2489
2490         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
2491
2492         /* If we are at a filemark, return a read length of 0 */
2493         if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
2494                 return 0;
2495
2496         /* Wait for the next block to reach the head of the pipeline. */
2497         idetape_init_read(drive, tape->max_stages);
2498         if (tape->first_stage == NULL) {
2499                 if (test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
2500                         return 0;
2501                 return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
2502                                         tape->merge_stage->bh);
2503         }
2504         idetape_wait_first_stage(drive);
2505         rq_ptr = &tape->first_stage->rq;
2506         bytes_read = tape->blk_size * (rq_ptr->nr_sectors -
2507                                         rq_ptr->current_nr_sectors);
2508         rq_ptr->nr_sectors = 0;
2509         rq_ptr->current_nr_sectors = 0;
2510
2511         if (rq_ptr->errors == IDETAPE_ERROR_EOD)
2512                 return 0;
2513         else {
2514                 idetape_switch_buffers(tape, tape->first_stage);
2515                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
2516                         set_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
2517                 spin_lock_irqsave(&tape->lock, flags);
2518                 idetape_remove_stage_head(drive);
2519                 spin_unlock_irqrestore(&tape->lock, flags);
2520                 tape->pipeline_head++;
2521                 idetape_calculate_speeds(drive);
2522         }
2523         if (bytes_read > blocks * tape->blk_size) {
2524                 printk(KERN_ERR "ide-tape: bug: trying to return more bytes"
2525                                 " than requested\n");
2526                 bytes_read = blocks * tape->blk_size;
2527         }
2528         return (bytes_read);
2529 }
2530
2531 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
2532 {
2533         idetape_tape_t *tape = drive->driver_data;
2534         struct idetape_bh *bh;
2535         int blocks;
2536
2537         while (bcount) {
2538                 unsigned int count;
2539
2540                 bh = tape->merge_stage->bh;
2541                 count = min(tape->stage_size, bcount);
2542                 bcount -= count;
2543                 blocks = count / tape->blk_size;
2544                 while (count) {
2545                         atomic_set(&bh->b_count,
2546                                    min(count, (unsigned int)bh->b_size));
2547                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
2548                         count -= atomic_read(&bh->b_count);
2549                         bh = bh->b_reqnext;
2550                 }
2551                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
2552                                       tape->merge_stage->bh);
2553         }
2554 }
2555
2556 static int idetape_pipeline_size(ide_drive_t *drive)
2557 {
2558         idetape_tape_t *tape = drive->driver_data;
2559         idetape_stage_t *stage;
2560         struct request *rq;
2561         int size = 0;
2562
2563         idetape_wait_for_pipeline(drive);
2564         stage = tape->first_stage;
2565         while (stage != NULL) {
2566                 rq = &stage->rq;
2567                 size += tape->blk_size * (rq->nr_sectors -
2568                                 rq->current_nr_sectors);
2569                 if (rq->errors == IDETAPE_ERROR_FILEMARK)
2570                         size += tape->blk_size;
2571                 stage = stage->next;
2572         }
2573         size += tape->merge_stage_size;
2574         return size;
2575 }
2576
2577 /*
2578  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
2579  * currently support only one partition.
2580  */
2581 static int idetape_rewind_tape(ide_drive_t *drive)
2582 {
2583         int retval;
2584         struct ide_atapi_pc pc;
2585         idetape_tape_t *tape;
2586         tape = drive->driver_data;
2587
2588         debug_log(DBG_SENSE, "Enter %s\n", __func__);
2589
2590         idetape_create_rewind_cmd(drive, &pc);
2591         retval = idetape_queue_pc_tail(drive, &pc);
2592         if (retval)
2593                 return retval;
2594
2595         idetape_create_read_position_cmd(&pc);
2596         retval = idetape_queue_pc_tail(drive, &pc);
2597         if (retval)
2598                 return retval;
2599         return 0;
2600 }
2601
2602 /* mtio.h compatible commands should be issued to the chrdev interface. */
2603 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
2604                                 unsigned long arg)
2605 {
2606         idetape_tape_t *tape = drive->driver_data;
2607         void __user *argp = (void __user *)arg;
2608
2609         struct idetape_config {
2610                 int dsc_rw_frequency;
2611                 int dsc_media_access_frequency;
2612                 int nr_stages;
2613         } config;
2614
2615         debug_log(DBG_PROCS, "Enter %s\n", __func__);
2616
2617         switch (cmd) {
2618         case 0x0340:
2619                 if (copy_from_user(&config, argp, sizeof(config)))
2620                         return -EFAULT;
2621                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
2622                 tape->max_stages = config.nr_stages;
2623                 break;
2624         case 0x0350:
2625                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
2626                 config.nr_stages = tape->max_stages;
2627                 if (copy_to_user(argp, &config, sizeof(config)))
2628                         return -EFAULT;
2629                 break;
2630         default:
2631                 return -EIO;
2632         }
2633         return 0;
2634 }
2635
2636 /*
2637  * The function below is now a bit more complicated than just passing the
2638  * command to the tape since we may have crossed some filemarks during our
2639  * pipelined read-ahead mode. As a minor side effect, the pipeline enables us to
2640  * support MTFSFM when the filemark is in our internal pipeline even if the tape
2641  * doesn't support spacing over filemarks in the reverse direction.
2642  */
2643 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
2644                                         int mt_count)
2645 {
2646         idetape_tape_t *tape = drive->driver_data;
2647         struct ide_atapi_pc pc;
2648         unsigned long flags;
2649         int retval, count = 0;
2650         int sprev = !!(tape->caps[4] & 0x20);
2651
2652         if (mt_count == 0)
2653                 return 0;
2654         if (MTBSF == mt_op || MTBSFM == mt_op) {
2655                 if (!sprev)
2656                         return -EIO;
2657                 mt_count = -mt_count;
2658         }
2659
2660         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2661                 /* its a read-ahead buffer, scan it for crossed filemarks. */
2662                 tape->merge_stage_size = 0;
2663                 if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
2664                         ++count;
2665                 while (tape->first_stage != NULL) {
2666                         if (count == mt_count) {
2667                                 if (mt_op == MTFSFM)
2668                                         set_bit(IDETAPE_FLAG_FILEMARK,
2669                                                 &tape->flags);
2670                                 return 0;
2671                         }
2672                         spin_lock_irqsave(&tape->lock, flags);
2673                         if (tape->first_stage == tape->active_stage) {
2674                                 /*
2675                                  * We have reached the active stage in the read
2676                                  * pipeline. There is no point in allowing the
2677                                  * drive to continue reading any farther, so we
2678                                  * stop the pipeline.
2679                                  *
2680                                  * This section should be moved to a separate
2681                                  * subroutine because similar operations are
2682                                  * done in __idetape_discard_read_pipeline(),
2683                                  * for example.
2684                                  */
2685                                 tape->next_stage = NULL;
2686                                 spin_unlock_irqrestore(&tape->lock, flags);
2687                                 idetape_wait_first_stage(drive);
2688                                 tape->next_stage = tape->first_stage->next;
2689                         } else
2690                                 spin_unlock_irqrestore(&tape->lock, flags);
2691                         if (tape->first_stage->rq.errors ==
2692                                         IDETAPE_ERROR_FILEMARK)
2693                                 ++count;
2694                         idetape_remove_stage_head(drive);
2695                 }
2696                 idetape_discard_read_pipeline(drive, 0);
2697         }
2698
2699         /*
2700          * The filemark was not found in our internal pipeline; now we can issue
2701          * the space command.
2702          */
2703         switch (mt_op) {
2704         case MTFSF:
2705         case MTBSF:
2706                 idetape_create_space_cmd(&pc, mt_count - count,
2707                                          IDETAPE_SPACE_OVER_FILEMARK);
2708                 return idetape_queue_pc_tail(drive, &pc);
2709         case MTFSFM:
2710         case MTBSFM:
2711                 if (!sprev)
2712                         return -EIO;
2713                 retval = idetape_space_over_filemarks(drive, MTFSF,
2714                                                       mt_count - count);
2715                 if (retval)
2716                         return retval;
2717                 count = (MTBSFM == mt_op ? 1 : -1);
2718                 return idetape_space_over_filemarks(drive, MTFSF, count);
2719         default:
2720                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2721                                 mt_op);
2722                 return -EIO;
2723         }
2724 }
2725
2726 /*
2727  * Our character device read / write functions.
2728  *
2729  * The tape is optimized to maximize throughput when it is transferring an
2730  * integral number of the "continuous transfer limit", which is a parameter of
2731  * the specific tape (26kB on my particular tape, 32kB for Onstream).
2732  *
2733  * As of version 1.3 of the driver, the character device provides an abstract
2734  * continuous view of the media - any mix of block sizes (even 1 byte) on the
2735  * same backup/restore procedure is supported. The driver will internally
2736  * convert the requests to the recommended transfer unit, so that an unmatch
2737  * between the user's block size to the recommended size will only result in a
2738  * (slightly) increased driver overhead, but will no longer hit performance.
2739  * This is not applicable to Onstream.
2740  */
2741 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
2742                                    size_t count, loff_t *ppos)
2743 {
2744         struct ide_tape_obj *tape = ide_tape_f(file);
2745         ide_drive_t *drive = tape->drive;
2746         ssize_t bytes_read, temp, actually_read = 0, rc;
2747         ssize_t ret = 0;
2748         u16 ctl = *(u16 *)&tape->caps[12];
2749
2750         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2751
2752         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
2753                 if (test_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags))
2754                         if (count > tape->blk_size &&
2755                             (count % tape->blk_size) == 0)
2756                                 tape->user_bs_factor = count / tape->blk_size;
2757         }
2758         rc = idetape_init_read(drive, tape->max_stages);
2759         if (rc < 0)
2760                 return rc;
2761         if (count == 0)
2762                 return (0);
2763         if (tape->merge_stage_size) {
2764                 actually_read = min((unsigned int)(tape->merge_stage_size),
2765                                     (unsigned int)count);
2766                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
2767                                                actually_read))
2768                         ret = -EFAULT;
2769                 buf += actually_read;
2770                 tape->merge_stage_size -= actually_read;
2771                 count -= actually_read;
2772         }
2773         while (count >= tape->stage_size) {
2774                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2775                 if (bytes_read <= 0)
2776                         goto finish;
2777                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
2778                                                bytes_read))
2779                         ret = -EFAULT;
2780                 buf += bytes_read;
2781                 count -= bytes_read;
2782                 actually_read += bytes_read;
2783         }
2784         if (count) {
2785                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2786                 if (bytes_read <= 0)
2787                         goto finish;
2788                 temp = min((unsigned long)count, (unsigned long)bytes_read);
2789                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
2790                                                temp))
2791                         ret = -EFAULT;
2792                 actually_read += temp;
2793                 tape->merge_stage_size = bytes_read-temp;
2794         }
2795 finish:
2796         if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
2797                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
2798
2799                 idetape_space_over_filemarks(drive, MTFSF, 1);
2800                 return 0;
2801         }
2802
2803         return ret ? ret : actually_read;
2804 }
2805
2806 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
2807                                      size_t count, loff_t *ppos)
2808 {
2809         struct ide_tape_obj *tape = ide_tape_f(file);
2810         ide_drive_t *drive = tape->drive;
2811         ssize_t actually_written = 0;
2812         ssize_t ret = 0;
2813         u16 ctl = *(u16 *)&tape->caps[12];
2814
2815         /* The drive is write protected. */
2816         if (tape->write_prot)
2817                 return -EACCES;
2818
2819         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2820
2821         /* Initialize write operation */
2822         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2823                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2824                         idetape_discard_read_pipeline(drive, 1);
2825                 if (tape->merge_stage || tape->merge_stage_size) {
2826                         printk(KERN_ERR "ide-tape: merge_stage_size "
2827                                 "should be 0 now\n");
2828                         tape->merge_stage_size = 0;
2829                 }
2830                 tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
2831                 if (!tape->merge_stage)
2832                         return -ENOMEM;
2833                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
2834                 idetape_init_merge_stage(tape);
2835
2836                 /*
2837                  * Issue a write 0 command to ensure that DSC handshake is
2838                  * switched from completion mode to buffer available mode. No
2839                  * point in issuing this if DSC overlap isn't supported, some
2840                  * drives (Seagate STT3401A) will return an error.
2841                  */
2842                 if (drive->dsc_overlap) {
2843                         ssize_t retval = idetape_queue_rw_tail(drive,
2844                                                         REQ_IDETAPE_WRITE, 0,
2845                                                         tape->merge_stage->bh);
2846                         if (retval < 0) {
2847                                 __idetape_kfree_stage(tape->merge_stage);
2848                                 tape->merge_stage = NULL;
2849                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2850                                 return retval;
2851                         }
2852                 }
2853         }
2854         if (count == 0)
2855                 return (0);
2856         if (tape->restart_speed_control_req)
2857                 idetape_restart_speed_control(drive);
2858         if (tape->merge_stage_size) {
2859                 if (tape->merge_stage_size >= tape->stage_size) {
2860                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
2861                         tape->merge_stage_size = 0;
2862                 }
2863                 actually_written = min((unsigned int)
2864                                 (tape->stage_size - tape->merge_stage_size),
2865                                 (unsigned int)count);
2866                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
2867                                                  actually_written))
2868                                 ret = -EFAULT;
2869                 buf += actually_written;
2870                 tape->merge_stage_size += actually_written;
2871                 count -= actually_written;
2872
2873                 if (tape->merge_stage_size == tape->stage_size) {
2874                         ssize_t retval;
2875                         tape->merge_stage_size = 0;
2876                         retval = idetape_add_chrdev_write_request(drive, ctl);
2877                         if (retval <= 0)
2878                                 return (retval);
2879                 }
2880         }
2881         while (count >= tape->stage_size) {
2882                 ssize_t retval;
2883                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
2884                                                  tape->stage_size))
2885                         ret = -EFAULT;
2886                 buf += tape->stage_size;
2887                 count -= tape->stage_size;
2888                 retval = idetape_add_chrdev_write_request(drive, ctl);
2889                 actually_written += tape->stage_size;
2890                 if (retval <= 0)
2891                         return (retval);
2892         }
2893         if (count) {
2894                 actually_written += count;
2895                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
2896                                                  count))
2897                         ret = -EFAULT;
2898                 tape->merge_stage_size += count;
2899         }
2900         return ret ? ret : actually_written;
2901 }
2902
2903 static int idetape_write_filemark(ide_drive_t *drive)
2904 {
2905         struct ide_atapi_pc pc;
2906
2907         /* Write a filemark */
2908         idetape_create_write_filemark_cmd(drive, &pc, 1);
2909         if (idetape_queue_pc_tail(drive, &pc)) {
2910                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
2911                 return -EIO;
2912         }
2913         return 0;
2914 }
2915
2916 /*
2917  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
2918  * requested.
2919  *
2920  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
2921  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
2922  * usually not supported (it is supported in the rare case in which we crossed
2923  * the filemark during our read-ahead pipelined operation mode).
2924  *
2925  * The following commands are currently not supported:
2926  *
2927  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
2928  * MT_ST_WRITE_THRESHOLD.
2929  */
2930 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
2931 {
2932         idetape_tape_t *tape = drive->driver_data;
2933         struct ide_atapi_pc pc;
2934         int i, retval;
2935
2936         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
2937                         mt_op, mt_count);
2938
2939         /* Commands which need our pipelined read-ahead stages. */
2940         switch (mt_op) {
2941         case MTFSF:
2942         case MTFSFM:
2943         case MTBSF:
2944         case MTBSFM:
2945                 if (!mt_count)
2946                         return 0;
2947                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
2948         default:
2949                 break;
2950         }
2951
2952         switch (mt_op) {
2953         case MTWEOF:
2954                 if (tape->write_prot)
2955                         return -EACCES;
2956                 idetape_discard_read_pipeline(drive, 1);
2957                 for (i = 0; i < mt_count; i++) {
2958                         retval = idetape_write_filemark(drive);
2959                         if (retval)
2960                                 return retval;
2961                 }
2962                 return 0;
2963         case MTREW:
2964                 idetape_discard_read_pipeline(drive, 0);
2965                 if (idetape_rewind_tape(drive))
2966                         return -EIO;
2967                 return 0;
2968         case MTLOAD:
2969                 idetape_discard_read_pipeline(drive, 0);
2970                 idetape_create_load_unload_cmd(drive, &pc,
2971                                                IDETAPE_LU_LOAD_MASK);
2972                 return idetape_queue_pc_tail(drive, &pc);
2973         case MTUNLOAD:
2974         case MTOFFL:
2975                 /*
2976                  * If door is locked, attempt to unlock before
2977                  * attempting to eject.
2978                  */
2979                 if (tape->door_locked) {
2980                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2981                                 if (!idetape_queue_pc_tail(drive, &pc))
2982                                         tape->door_locked = DOOR_UNLOCKED;
2983                 }
2984                 idetape_discard_read_pipeline(drive, 0);
2985                 idetape_create_load_unload_cmd(drive, &pc,
2986                                               !IDETAPE_LU_LOAD_MASK);
2987                 retval = idetape_queue_pc_tail(drive, &pc);
2988                 if (!retval)
2989                         clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
2990                 return retval;
2991         case MTNOP:
2992                 idetape_discard_read_pipeline(drive, 0);
2993                 return idetape_flush_tape_buffers(drive);
2994         case MTRETEN:
2995                 idetape_discard_read_pipeline(drive, 0);
2996                 idetape_create_load_unload_cmd(drive, &pc,
2997                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2998                 return idetape_queue_pc_tail(drive, &pc);
2999         case MTEOM:
3000                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
3001                 return idetape_queue_pc_tail(drive, &pc);
3002         case MTERASE:
3003                 (void)idetape_rewind_tape(drive);
3004                 idetape_create_erase_cmd(&pc);
3005                 return idetape_queue_pc_tail(drive, &pc);
3006         case MTSETBLK:
3007                 if (mt_count) {
3008                         if (mt_count < tape->blk_size ||
3009                             mt_count % tape->blk_size)
3010                                 return -EIO;
3011                         tape->user_bs_factor = mt_count / tape->blk_size;
3012                         clear_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
3013                 } else
3014                         set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
3015                 return 0;
3016         case MTSEEK:
3017                 idetape_discard_read_pipeline(drive, 0);
3018                 return idetape_position_tape(drive,
3019                         mt_count * tape->user_bs_factor, tape->partition, 0);
3020         case MTSETPART:
3021                 idetape_discard_read_pipeline(drive, 0);
3022                 return idetape_position_tape(drive, 0, mt_count, 0);
3023         case MTFSR:
3024         case MTBSR:
3025         case MTLOCK:
3026                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
3027                         return 0;
3028                 retval = idetape_queue_pc_tail(drive, &pc);
3029                 if (retval)
3030                         return retval;
3031                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
3032                 return 0;
3033         case MTUNLOCK:
3034                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
3035                         return 0;
3036                 retval = idetape_queue_pc_tail(drive, &pc);
3037                 if (retval)
3038                         return retval;
3039                 tape->door_locked = DOOR_UNLOCKED;
3040                 return 0;
3041         default:
3042                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
3043                                 mt_op);
3044                 return -EIO;
3045         }
3046 }
3047
3048 /*
3049  * Our character device ioctls. General mtio.h magnetic io commands are
3050  * supported here, and not in the corresponding block interface. Our own
3051  * ide-tape ioctls are supported on both interfaces.
3052  */
3053 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
3054                                 unsigned int cmd, unsigned long arg)
3055 {
3056         struct ide_tape_obj *tape = ide_tape_f(file);
3057         ide_drive_t *drive = tape->drive;
3058         struct mtop mtop;
3059         struct mtget mtget;
3060         struct mtpos mtpos;
3061         int block_offset = 0, position = tape->first_frame;
3062         void __user *argp = (void __user *)arg;
3063
3064         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
3065
3066         tape->restart_speed_control_req = 1;
3067         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
3068                 idetape_empty_write_pipeline(drive);
3069                 idetape_flush_tape_buffers(drive);
3070         }
3071         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
3072                 block_offset = idetape_pipeline_size(drive) /
3073                         (tape->blk_size * tape->user_bs_factor);
3074                 position = idetape_read_position(drive);
3075                 if (position < 0)
3076                         return -EIO;
3077         }
3078         switch (cmd) {
3079         case MTIOCTOP:
3080                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
3081                         return -EFAULT;
3082                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
3083         case MTIOCGET:
3084                 memset(&mtget, 0, sizeof(struct mtget));
3085                 mtget.mt_type = MT_ISSCSI2;
3086                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
3087                 mtget.mt_dsreg =
3088                         ((tape->blk_size * tape->user_bs_factor)
3089                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
3090
3091                 if (tape->drv_write_prot)
3092                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
3093
3094                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
3095                         return -EFAULT;
3096                 return 0;
3097         case MTIOCPOS:
3098                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
3099                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
3100                         return -EFAULT;
3101                 return 0;
3102         default:
3103                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
3104                         idetape_discard_read_pipeline(drive, 1);
3105                 return idetape_blkdev_ioctl(drive, cmd, arg);
3106         }
3107 }
3108
3109 /*
3110  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
3111  * block size with the reported value.
3112  */
3113 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
3114 {
3115         idetape_tape_t *tape = drive->driver_data;
3116         struct ide_atapi_pc pc;
3117
3118         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
3119         if (idetape_queue_pc_tail(drive, &pc)) {
3120                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
3121                 if (tape->blk_size == 0) {
3122                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
3123                                             "block size, assuming 32k\n");
3124                         tape->blk_size = 32768;
3125                 }
3126                 return;
3127         }
3128         tape->blk_size = (pc.buf[4 + 5] << 16) +
3129                                 (pc.buf[4 + 6] << 8)  +
3130                                  pc.buf[4 + 7];
3131         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
3132 }
3133
3134 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
3135 {
3136         unsigned int minor = iminor(inode), i = minor & ~0xc0;
3137         ide_drive_t *drive;
3138         idetape_tape_t *tape;
3139         struct ide_atapi_pc pc;
3140         int retval;
3141
3142         if (i >= MAX_HWIFS * MAX_DRIVES)
3143                 return -ENXIO;
3144
3145         tape = ide_tape_chrdev_get(i);
3146         if (!tape)
3147                 return -ENXIO;
3148
3149         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
3150
3151         /*
3152          * We really want to do nonseekable_open(inode, filp); here, but some
3153          * versions of tar incorrectly call lseek on tapes and bail out if that
3154          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
3155          */
3156         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
3157
3158         drive = tape->drive;
3159
3160         filp->private_data = tape;
3161
3162         if (test_and_set_bit(IDETAPE_FLAG_BUSY, &tape->flags)) {
3163                 retval = -EBUSY;
3164                 goto out_put_tape;
3165         }
3166
3167         retval = idetape_wait_ready(drive, 60 * HZ);
3168         if (retval) {
3169                 clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
3170                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
3171                 goto out_put_tape;
3172         }
3173
3174         idetape_read_position(drive);
3175         if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
3176                 (void)idetape_rewind_tape(drive);
3177
3178         if (tape->chrdev_dir != IDETAPE_DIR_READ)
3179                 clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
3180
3181         /* Read block size and write protect status from drive. */
3182         ide_tape_get_bsize_from_bdesc(drive);
3183
3184         /* Set write protect flag if device is opened as read-only. */
3185         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
3186                 tape->write_prot = 1;
3187         else
3188                 tape->write_prot = tape->drv_write_prot;
3189
3190         /* Make sure drive isn't write protected if user wants to write. */
3191         if (tape->write_prot) {
3192                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
3193                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
3194                         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
3195                         retval = -EROFS;
3196                         goto out_put_tape;
3197                 }
3198         }
3199
3200         /* Lock the tape drive door so user can't eject. */
3201         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
3202                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
3203                         if (!idetape_queue_pc_tail(drive, &pc)) {
3204                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
3205                                         tape->door_locked = DOOR_LOCKED;
3206                         }
3207                 }
3208         }
3209         idetape_restart_speed_control(drive);
3210         tape->restart_speed_control_req = 0;
3211         return 0;
3212
3213 out_put_tape:
3214         ide_tape_put(tape);
3215         return retval;
3216 }
3217
3218 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
3219 {
3220         idetape_tape_t *tape = drive->driver_data;
3221
3222         idetape_empty_write_pipeline(drive);
3223         tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
3224         if (tape->merge_stage != NULL) {
3225                 idetape_pad_zeros(drive, tape->blk_size *
3226                                 (tape->user_bs_factor - 1));
3227                 __idetape_kfree_stage(tape->merge_stage);
3228                 tape->merge_stage = NULL;
3229         }
3230         idetape_write_filemark(drive);
3231         idetape_flush_tape_buffers(drive);
3232         idetape_flush_tape_buffers(drive);
3233 }
3234
3235 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
3236 {
3237         struct ide_tape_obj *tape = ide_tape_f(filp);
3238         ide_drive_t *drive = tape->drive;
3239         struct ide_atapi_pc pc;
3240         unsigned int minor = iminor(inode);
3241
3242         lock_kernel();
3243         tape = drive->driver_data;
3244
3245         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
3246
3247         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
3248                 idetape_write_release(drive, minor);
3249         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
3250                 if (minor < 128)
3251                         idetape_discard_read_pipeline(drive, 1);
3252                 else
3253                         idetape_wait_for_pipeline(drive);
3254         }
3255         if (tape->cache_stage != NULL) {
3256                 __idetape_kfree_stage(tape->cache_stage);
3257                 tape->cache_stage = NULL;
3258         }
3259         if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
3260                 (void) idetape_rewind_tape(drive);
3261         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
3262                 if (tape->door_locked == DOOR_LOCKED) {
3263                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
3264                                 if (!idetape_queue_pc_tail(drive, &pc))
3265                                         tape->door_locked = DOOR_UNLOCKED;
3266                         }
3267                 }
3268         }
3269         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
3270         ide_tape_put(tape);
3271         unlock_kernel();
3272         return 0;
3273 }
3274
3275 /*
3276  * check the contents of the ATAPI IDENTIFY command results. We return:
3277  *
3278  * 1 - If the tape can be supported by us, based on the information we have so
3279  * far.
3280  *
3281  * 0 - If this tape driver is not currently supported by us.
3282  */
3283 static int idetape_identify_device(ide_drive_t *drive)
3284 {
3285         u8 gcw[2], protocol, device_type, removable, packet_size;
3286
3287         if (drive->id_read == 0)
3288                 return 1;
3289
3290         *((unsigned short *) &gcw) = drive->id->config;
3291
3292         protocol        =   (gcw[1] & 0xC0) >> 6;
3293         device_type     =    gcw[1] & 0x1F;
3294         removable       = !!(gcw[0] & 0x80);
3295         packet_size     =    gcw[0] & 0x3;
3296
3297         /* Check that we can support this device */
3298         if (protocol != 2)
3299                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
3300                                 protocol);
3301         else if (device_type != 1)
3302                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
3303                                 "to tape\n", device_type);
3304         else if (!removable)
3305                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
3306         else if (packet_size != 0) {
3307                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
3308                                 " bytes\n", packet_size);
3309         } else
3310                 return 1;
3311         return 0;
3312 }
3313
3314 static void idetape_get_inquiry_results(ide_drive_t *drive)
3315 {
3316         idetape_tape_t *tape = drive->driver_data;
3317         struct ide_atapi_pc pc;
3318         char fw_rev[6], vendor_id[10], product_id[18];
3319
3320         idetape_create_inquiry_cmd(&pc);
3321         if (idetape_queue_pc_tail(drive, &pc)) {
3322                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
3323                                 tape->name);
3324                 return;
3325         }
3326         memcpy(vendor_id, &pc.buf[8], 8);
3327         memcpy(product_id, &pc.buf[16], 16);
3328         memcpy(fw_rev, &pc.buf[32], 4);
3329
3330         ide_fixstring(vendor_id, 10, 0);
3331         ide_fixstring(product_id, 18, 0);
3332         ide_fixstring(fw_rev, 6, 0);
3333
3334         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
3335                         drive->name, tape->name, vendor_id, product_id, fw_rev);
3336 }
3337
3338 /*
3339  * Ask the tape about its various parameters. In particular, we will adjust our
3340  * data transfer buffer size to the recommended value as returned by the tape.
3341  */
3342 static void idetape_get_mode_sense_results(ide_drive_t *drive)
3343 {
3344         idetape_tape_t *tape = drive->driver_data;
3345         struct ide_atapi_pc pc;
3346         u8 *caps;
3347         u8 speed, max_speed;
3348
3349         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
3350         if (idetape_queue_pc_tail(drive, &pc)) {
3351                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
3352                                 " some default values\n");
3353                 tape->blk_size = 512;
3354                 put_unaligned(52,   (u16 *)&tape->caps[12]);
3355                 put_unaligned(540,  (u16 *)&tape->caps[14]);
3356                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
3357                 return;
3358         }
3359         caps = pc.buf + 4 + pc.buf[3];
3360
3361         /* convert to host order and save for later use */
3362         speed = be16_to_cpu(*(u16 *)&caps[14]);
3363         max_speed = be16_to_cpu(*(u16 *)&caps[8]);
3364
3365         put_unaligned(max_speed, (u16 *)&caps[8]);
3366         put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
3367         put_unaligned(speed, (u16 *)&caps[14]);
3368         put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
3369
3370         if (!speed) {
3371                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
3372                                 "(assuming 650KB/sec)\n", drive->name);
3373                 put_unaligned(650, (u16 *)&caps[14]);
3374         }
3375         if (!max_speed) {
3376                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
3377                                 "(assuming 650KB/sec)\n", drive->name);
3378                 put_unaligned(650, (u16 *)&caps[8]);
3379         }
3380
3381         memcpy(&tape->caps, caps, 20);
3382         if (caps[7] & 0x02)
3383                 tape->blk_size = 512;
3384         else if (caps[7] & 0x04)
3385                 tape->blk_size = 1024;
3386 }
3387
3388 #ifdef CONFIG_IDE_PROC_FS
3389 static void idetape_add_settings(ide_drive_t *drive)
3390 {
3391         idetape_tape_t *tape = drive->driver_data;
3392
3393         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
3394                         1, 2, (u16 *)&tape->caps[16], NULL);
3395         ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff,
3396                         tape->stage_size / 1024, 1, &tape->min_pipeline, NULL);
3397         ide_add_setting(drive, "pipeline", SETTING_RW, TYPE_INT, 1, 0xffff,
3398                         tape->stage_size / 1024, 1, &tape->max_stages, NULL);
3399         ide_add_setting(drive, "pipeline_max", SETTING_RW, TYPE_INT, 1, 0xffff,
3400                         tape->stage_size / 1024, 1, &tape->max_pipeline, NULL);
3401         ide_add_setting(drive, "pipeline_used", SETTING_READ, TYPE_INT, 0,
3402                         0xffff, tape->stage_size / 1024, 1, &tape->nr_stages,
3403                         NULL);
3404         ide_add_setting(drive, "pipeline_pending", SETTING_READ, TYPE_INT, 0,
3405                         0xffff, tape->stage_size / 1024, 1,
3406                         &tape->nr_pending_stages, NULL);
3407         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
3408                         1, 1, (u16 *)&tape->caps[14], NULL);
3409         ide_add_setting(drive, "stage", SETTING_READ, TYPE_INT, 0, 0xffff, 1,
3410                         1024, &tape->stage_size, NULL);
3411         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
3412                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
3413                         NULL);
3414         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
3415                         1, &drive->dsc_overlap, NULL);
3416         ide_add_setting(drive, "pipeline_head_speed_c", SETTING_READ, TYPE_INT,
3417                         0, 0xffff, 1, 1, &tape->controlled_pipeline_head_speed,
3418                         NULL);
3419         ide_add_setting(drive, "pipeline_head_speed_u", SETTING_READ, TYPE_INT,
3420                         0, 0xffff, 1, 1,
3421                         &tape->uncontrolled_pipeline_head_speed, NULL);
3422         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
3423                         1, 1, &tape->avg_speed, NULL);
3424         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
3425                         1, &tape->debug_mask, NULL);
3426 }
3427 #else
3428 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
3429 #endif
3430
3431 /*
3432  * The function below is called to:
3433  *
3434  * 1. Initialize our various state variables.
3435  * 2. Ask the tape for its capabilities.
3436  * 3. Allocate a buffer which will be used for data transfer. The buffer size
3437  * is chosen based on the recommendation which we received in step 2.
3438  *
3439  * Note that at this point ide.c already assigned us an irq, so that we can
3440  * queue requests here and wait for their completion.
3441  */
3442 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
3443 {
3444         unsigned long t1, tmid, tn, t;
3445         int speed;
3446         int stage_size;
3447         u8 gcw[2];
3448         struct sysinfo si;
3449         u16 *ctl = (u16 *)&tape->caps[12];
3450
3451         spin_lock_init(&tape->lock);
3452         drive->dsc_overlap = 1;
3453         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
3454                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
3455                                  tape->name);
3456                 drive->dsc_overlap = 0;
3457         }
3458         /* Seagate Travan drives do not support DSC overlap. */
3459         if (strstr(drive->id->model, "Seagate STT3401"))
3460                 drive->dsc_overlap = 0;
3461         tape->minor = minor;
3462         tape->name[0] = 'h';
3463         tape->name[1] = 't';
3464         tape->name[2] = '0' + minor;
3465         tape->chrdev_dir = IDETAPE_DIR_NONE;
3466         tape->pc = tape->pc_stack;
3467         tape->max_insert_speed = 10000;
3468         tape->speed_control = 1;
3469         *((unsigned short *) &gcw) = drive->id->config;
3470
3471         /* Command packet DRQ type */
3472         if (((gcw[0] & 0x60) >> 5) == 1)
3473                 set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
3474
3475         tape->min_pipeline = 10;
3476         tape->max_pipeline = 10;
3477         tape->max_stages   = 10;
3478
3479         idetape_get_inquiry_results(drive);
3480         idetape_get_mode_sense_results(drive);
3481         ide_tape_get_bsize_from_bdesc(drive);
3482         tape->user_bs_factor = 1;
3483         tape->stage_size = *ctl * tape->blk_size;
3484         while (tape->stage_size > 0xffff) {
3485                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
3486                 *ctl /= 2;
3487                 tape->stage_size = *ctl * tape->blk_size;
3488         }
3489         stage_size = tape->stage_size;
3490         tape->pages_per_stage = stage_size / PAGE_SIZE;
3491         if (stage_size % PAGE_SIZE) {
3492                 tape->pages_per_stage++;
3493                 tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
3494         }
3495
3496         /* Select the "best" DSC read/write polling freq and pipeline size. */
3497         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
3498
3499         tape->max_stages = speed * 1000 * 10 / tape->stage_size;
3500
3501         /* Limit memory use for pipeline to 10% of physical memory */
3502         si_meminfo(&si);
3503         if (tape->max_stages * tape->stage_size >
3504                         si.totalram * si.mem_unit / 10)
3505                 tape->max_stages =
3506                         si.totalram * si.mem_unit / (10 * tape->stage_size);
3507
3508         tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
3509         tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
3510         tape->max_pipeline =
3511                 min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
3512         if (tape->max_stages == 0) {
3513                 tape->max_stages   = 1;
3514                 tape->min_pipeline = 1;
3515                 tape->max_pipeline = 1;
3516         }
3517
3518         t1 = (tape->stage_size * HZ) / (speed * 1000);
3519         tmid = (*(u16 *)&tape->caps[16] * 32 * HZ) / (speed * 125);
3520         tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
3521
3522         if (tape->max_stages)
3523                 t = tn;
3524         else
3525                 t = t1;
3526
3527         /*
3528          * Ensure that the number we got makes sense; limit it within
3529          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
3530          */
3531         tape->best_dsc_rw_freq = max_t(unsigned long,
3532                                 min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
3533                                 IDETAPE_DSC_RW_MIN);
3534         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
3535                 "%dkB pipeline, %lums tDSC%s\n",
3536                 drive->name, tape->name, *(u16 *)&tape->caps[14],
3537                 (*(u16 *)&tape->caps[16] * 512) / tape->stage_size,
3538                 tape->stage_size / 1024,
3539                 tape->max_stages * tape->stage_size / 1024,
3540                 tape->best_dsc_rw_freq * 1000 / HZ,
3541                 drive->using_dma ? ", DMA":"");
3542
3543         idetape_add_settings(drive);
3544 }
3545
3546 static void ide_tape_remove(ide_drive_t *drive)
3547 {
3548         idetape_tape_t *tape = drive->driver_data;
3549
3550         ide_proc_unregister_driver(drive, tape->driver);
3551
3552         ide_unregister_region(tape->disk);
3553
3554         ide_tape_put(tape);
3555 }
3556
3557 static void ide_tape_release(struct kref *kref)
3558 {
3559         struct ide_tape_obj *tape = to_ide_tape(kref);
3560         ide_drive_t *drive = tape->drive;
3561         struct gendisk *g = tape->disk;
3562
3563         BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
3564
3565         drive->dsc_overlap = 0;
3566         drive->driver_data = NULL;
3567         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
3568         device_destroy(idetape_sysfs_class,
3569                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
3570         idetape_devs[tape->minor] = NULL;
3571         g->private_data = NULL;
3572         put_disk(g);
3573         kfree(tape);
3574 }
3575
3576 #ifdef CONFIG_IDE_PROC_FS
3577 static int proc_idetape_read_name
3578         (char *page, char **start, off_t off, int count, int *eof, void *data)
3579 {
3580         ide_drive_t     *drive = (ide_drive_t *) data;
3581         idetape_tape_t  *tape = drive->driver_data;
3582         char            *out = page;
3583         int             len;
3584
3585         len = sprintf(out, "%s\n", tape->name);
3586         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
3587 }
3588
3589 static ide_proc_entry_t idetape_proc[] = {
3590         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
3591         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
3592         { NULL, 0, NULL, NULL }
3593 };
3594 #endif
3595
3596 static int ide_tape_probe(ide_drive_t *);
3597
3598 static ide_driver_t idetape_driver = {
3599         .gen_driver = {
3600                 .owner          = THIS_MODULE,
3601                 .name           = "ide-tape",
3602                 .bus            = &ide_bus_type,
3603         },
3604         .probe                  = ide_tape_probe,
3605         .remove                 = ide_tape_remove,
3606         .version                = IDETAPE_VERSION,
3607         .media                  = ide_tape,
3608         .supports_dsc_overlap   = 1,
3609         .do_request             = idetape_do_request,
3610         .end_request            = idetape_end_request,
3611         .error                  = __ide_error,
3612         .abort                  = __ide_abort,
3613 #ifdef CONFIG_IDE_PROC_FS
3614         .proc                   = idetape_proc,
3615 #endif
3616 };
3617
3618 /* Our character device supporting functions, passed to register_chrdev. */
3619 static const struct file_operations idetape_fops = {
3620         .owner          = THIS_MODULE,
3621         .read           = idetape_chrdev_read,
3622         .write          = idetape_chrdev_write,
3623         .ioctl          = idetape_chrdev_ioctl,
3624         .open           = idetape_chrdev_open,
3625         .release        = idetape_chrdev_release,
3626 };
3627
3628 static int idetape_open(struct inode *inode, struct file *filp)
3629 {
3630         struct gendisk *disk = inode->i_bdev->bd_disk;
3631         struct ide_tape_obj *tape;
3632
3633         tape = ide_tape_get(disk);
3634         if (!tape)
3635                 return -ENXIO;
3636
3637         return 0;
3638 }
3639
3640 static int idetape_release(struct inode *inode, struct file *filp)
3641 {
3642         struct gendisk *disk = inode->i_bdev->bd_disk;
3643         struct ide_tape_obj *tape = ide_tape_g(disk);
3644
3645         ide_tape_put(tape);
3646
3647         return 0;
3648 }
3649
3650 static int idetape_ioctl(struct inode *inode, struct file *file,
3651                         unsigned int cmd, unsigned long arg)
3652 {
3653         struct block_device *bdev = inode->i_bdev;
3654         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
3655         ide_drive_t *drive = tape->drive;
3656         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
3657         if (err == -EINVAL)
3658                 err = idetape_blkdev_ioctl(drive, cmd, arg);
3659         return err;
3660 }
3661
3662 static struct block_device_operations idetape_block_ops = {
3663         .owner          = THIS_MODULE,
3664         .open           = idetape_open,
3665         .release        = idetape_release,
3666         .ioctl          = idetape_ioctl,
3667 };
3668
3669 static int ide_tape_probe(ide_drive_t *drive)
3670 {
3671         idetape_tape_t *tape;
3672         struct gendisk *g;
3673         int minor;
3674
3675         if (!strstr("ide-tape", drive->driver_req))
3676                 goto failed;
3677         if (!drive->present)
3678                 goto failed;
3679         if (drive->media != ide_tape)
3680                 goto failed;
3681         if (!idetape_identify_device(drive)) {
3682                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
3683                                 " the driver\n", drive->name);
3684                 goto failed;
3685         }
3686         if (drive->scsi) {
3687                 printk(KERN_INFO "ide-tape: passing drive %s to ide-scsi"
3688                                  " emulation.\n", drive->name);
3689                 goto failed;
3690         }
3691         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
3692         if (tape == NULL) {
3693                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
3694                                 drive->name);
3695                 goto failed;
3696         }
3697
3698         g = alloc_disk(1 << PARTN_BITS);
3699         if (!g)
3700                 goto out_free_tape;
3701
3702         ide_init_disk(g, drive);
3703
3704         ide_proc_register_driver(drive, &idetape_driver);
3705
3706         kref_init(&tape->kref);
3707
3708         tape->drive = drive;
3709         tape->driver = &idetape_driver;
3710         tape->disk = g;
3711
3712         g->private_data = &tape->driver;
3713
3714         drive->driver_data = tape;
3715
3716         mutex_lock(&idetape_ref_mutex);
3717         for (minor = 0; idetape_devs[minor]; minor++)
3718                 ;
3719         idetape_devs[minor] = tape;
3720         mutex_unlock(&idetape_ref_mutex);
3721
3722         idetape_setup(drive, tape, minor);
3723
3724         device_create(idetape_sysfs_class, &drive->gendev,
3725                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
3726         device_create(idetape_sysfs_class, &drive->gendev,
3727                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
3728
3729         g->fops = &idetape_block_ops;
3730         ide_register_region(g);
3731
3732         return 0;
3733
3734 out_free_tape:
3735         kfree(tape);
3736 failed:
3737         return -ENODEV;
3738 }
3739
3740 static void __exit idetape_exit(void)
3741 {
3742         driver_unregister(&idetape_driver.gen_driver);
3743         class_destroy(idetape_sysfs_class);
3744         unregister_chrdev(IDETAPE_MAJOR, "ht");
3745 }
3746
3747 static int __init idetape_init(void)
3748 {
3749         int error = 1;
3750         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
3751         if (IS_ERR(idetape_sysfs_class)) {
3752                 idetape_sysfs_class = NULL;
3753                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
3754                 error = -EBUSY;
3755                 goto out;
3756         }
3757
3758         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
3759                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
3760                                 " interface\n");
3761                 error = -EBUSY;
3762                 goto out_free_class;
3763         }
3764
3765         error = driver_register(&idetape_driver.gen_driver);
3766         if (error)
3767                 goto out_free_driver;
3768
3769         return 0;
3770
3771 out_free_driver:
3772         driver_unregister(&idetape_driver.gen_driver);
3773 out_free_class:
3774         class_destroy(idetape_sysfs_class);
3775 out:
3776         return error;
3777 }
3778
3779 MODULE_ALIAS("ide:*m-tape*");
3780 module_init(idetape_init);
3781 module_exit(idetape_exit);
3782 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
3783 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
3784 MODULE_LICENSE("GPL");