ide: add helpers for preparing sense requests
[linux-2.6.git] / drivers / ide / ide-atapi.c
1 /*
2  * ATAPI support.
3  */
4
5 #include <linux/kernel.h>
6 #include <linux/cdrom.h>
7 #include <linux/delay.h>
8 #include <linux/ide.h>
9 #include <linux/scatterlist.h>
10
11 #include <scsi/scsi.h>
12
13 #ifdef DEBUG
14 #define debug_log(fmt, args...) \
15         printk(KERN_INFO "ide: " fmt, ## args)
16 #else
17 #define debug_log(fmt, args...) do {} while (0)
18 #endif
19
20 #define ATAPI_MIN_CDB_BYTES     12
21
22 static inline int dev_is_idecd(ide_drive_t *drive)
23 {
24         return drive->media == ide_cdrom || drive->media == ide_optical;
25 }
26
27 /*
28  * Check whether we can support a device,
29  * based on the ATAPI IDENTIFY command results.
30  */
31 int ide_check_atapi_device(ide_drive_t *drive, const char *s)
32 {
33         u16 *id = drive->id;
34         u8 gcw[2], protocol, device_type, removable, drq_type, packet_size;
35
36         *((u16 *)&gcw) = id[ATA_ID_CONFIG];
37
38         protocol    = (gcw[1] & 0xC0) >> 6;
39         device_type =  gcw[1] & 0x1F;
40         removable   = (gcw[0] & 0x80) >> 7;
41         drq_type    = (gcw[0] & 0x60) >> 5;
42         packet_size =  gcw[0] & 0x03;
43
44 #ifdef CONFIG_PPC
45         /* kludge for Apple PowerBook internal zip */
46         if (drive->media == ide_floppy && device_type == 5 &&
47             !strstr((char *)&id[ATA_ID_PROD], "CD-ROM") &&
48             strstr((char *)&id[ATA_ID_PROD], "ZIP"))
49                 device_type = 0;
50 #endif
51
52         if (protocol != 2)
53                 printk(KERN_ERR "%s: %s: protocol (0x%02x) is not ATAPI\n",
54                         s, drive->name, protocol);
55         else if ((drive->media == ide_floppy && device_type != 0) ||
56                  (drive->media == ide_tape && device_type != 1))
57                 printk(KERN_ERR "%s: %s: invalid device type (0x%02x)\n",
58                         s, drive->name, device_type);
59         else if (removable == 0)
60                 printk(KERN_ERR "%s: %s: the removable flag is not set\n",
61                         s, drive->name);
62         else if (drive->media == ide_floppy && drq_type == 3)
63                 printk(KERN_ERR "%s: %s: sorry, DRQ type (0x%02x) not "
64                         "supported\n", s, drive->name, drq_type);
65         else if (packet_size != 0)
66                 printk(KERN_ERR "%s: %s: packet size (0x%02x) is not 12 "
67                         "bytes\n", s, drive->name, packet_size);
68         else
69                 return 1;
70         return 0;
71 }
72 EXPORT_SYMBOL_GPL(ide_check_atapi_device);
73
74 void ide_init_pc(struct ide_atapi_pc *pc)
75 {
76         memset(pc, 0, sizeof(*pc));
77         pc->buf = pc->pc_buf;
78         pc->buf_size = IDE_PC_BUFFER_SIZE;
79 }
80 EXPORT_SYMBOL_GPL(ide_init_pc);
81
82 /*
83  * Generate a new packet command request in front of the request queue, before
84  * the current request, so that it will be processed immediately, on the next
85  * pass through the driver.
86  */
87 static void ide_queue_pc_head(ide_drive_t *drive, struct gendisk *disk,
88                               struct ide_atapi_pc *pc, struct request *rq)
89 {
90         blk_rq_init(NULL, rq);
91         rq->cmd_type = REQ_TYPE_SPECIAL;
92         rq->cmd_flags |= REQ_PREEMPT;
93         rq->special = (char *)pc;
94         rq->rq_disk = disk;
95
96         if (pc->req_xfer) {
97                 rq->data = pc->buf;
98                 rq->data_len = pc->req_xfer;
99         }
100
101         memcpy(rq->cmd, pc->c, 12);
102         if (drive->media == ide_tape)
103                 rq->cmd[13] = REQ_IDETAPE_PC1;
104
105         drive->hwif->rq = NULL;
106
107         elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 0);
108 }
109
110 /*
111  * Add a special packet command request to the tail of the request queue,
112  * and wait for it to be serviced.
113  */
114 int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
115                       struct ide_atapi_pc *pc)
116 {
117         struct request *rq;
118         int error;
119
120         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
121         rq->cmd_type = REQ_TYPE_SPECIAL;
122         rq->special = (char *)pc;
123
124         if (pc->req_xfer) {
125                 rq->data = pc->buf;
126                 rq->data_len = pc->req_xfer;
127         }
128
129         memcpy(rq->cmd, pc->c, 12);
130         if (drive->media == ide_tape)
131                 rq->cmd[13] = REQ_IDETAPE_PC1;
132         error = blk_execute_rq(drive->queue, disk, rq, 0);
133         blk_put_request(rq);
134
135         return error;
136 }
137 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
138
139 int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
140 {
141         struct ide_atapi_pc pc;
142
143         ide_init_pc(&pc);
144         pc.c[0] = TEST_UNIT_READY;
145
146         return ide_queue_pc_tail(drive, disk, &pc);
147 }
148 EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);
149
150 int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
151 {
152         struct ide_atapi_pc pc;
153
154         ide_init_pc(&pc);
155         pc.c[0] = START_STOP;
156         pc.c[4] = start;
157
158         if (drive->media == ide_tape)
159                 pc.flags |= PC_FLAG_WAIT_FOR_DSC;
160
161         return ide_queue_pc_tail(drive, disk, &pc);
162 }
163 EXPORT_SYMBOL_GPL(ide_do_start_stop);
164
165 int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
166 {
167         struct ide_atapi_pc pc;
168
169         if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
170                 return 0;
171
172         ide_init_pc(&pc);
173         pc.c[0] = ALLOW_MEDIUM_REMOVAL;
174         pc.c[4] = on;
175
176         return ide_queue_pc_tail(drive, disk, &pc);
177 }
178 EXPORT_SYMBOL_GPL(ide_set_media_lock);
179
180 void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
181 {
182         ide_init_pc(pc);
183         pc->c[0] = REQUEST_SENSE;
184         if (drive->media == ide_floppy) {
185                 pc->c[4] = 255;
186                 pc->req_xfer = 18;
187         } else {
188                 pc->c[4] = 20;
189                 pc->req_xfer = 20;
190         }
191 }
192 EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);
193
194 void ide_prep_sense(ide_drive_t *drive, struct request *rq)
195 {
196         struct request_sense *sense = &drive->sense_data;
197         struct request *sense_rq = &drive->sense_rq;
198         unsigned int cmd_len, sense_len;
199
200         debug_log("%s: enter\n", __func__);
201
202         switch (drive->media) {
203         case ide_floppy:
204                 cmd_len = 255;
205                 sense_len = 18;
206                 break;
207         case ide_tape:
208                 cmd_len = 20;
209                 sense_len = 20;
210                 break;
211         default:
212                 cmd_len = 18;
213                 sense_len = 18;
214         }
215
216         BUG_ON(sense_len > sizeof(*sense));
217
218         if (blk_sense_request(rq) || drive->sense_rq_armed)
219                 return;
220
221         memset(sense, 0, sizeof(*sense));
222
223         blk_rq_init(rq->q, sense_rq);
224         sense_rq->rq_disk = rq->rq_disk;
225
226         sense_rq->data = sense;
227         sense_rq->cmd[0] = GPCMD_REQUEST_SENSE;
228         sense_rq->cmd[4] = cmd_len;
229         sense_rq->data_len = sense_len;
230
231         sense_rq->cmd_type = REQ_TYPE_SENSE;
232         sense_rq->cmd_flags |= REQ_PREEMPT;
233
234         if (drive->media == ide_tape)
235                 sense_rq->cmd[13] = REQ_IDETAPE_PC1;
236
237         drive->sense_rq_armed = true;
238 }
239 EXPORT_SYMBOL_GPL(ide_prep_sense);
240
241 void ide_queue_sense_rq(ide_drive_t *drive, void *special)
242 {
243         BUG_ON(!drive->sense_rq_armed);
244
245         drive->sense_rq.special = special;
246         drive->sense_rq_armed = false;
247
248         drive->hwif->rq = NULL;
249
250         elv_add_request(drive->queue, &drive->sense_rq,
251                         ELEVATOR_INSERT_FRONT, 0);
252 }
253 EXPORT_SYMBOL_GPL(ide_queue_sense_rq);
254
255 /*
256  * Called when an error was detected during the last packet command.
257  * We queue a request sense packet command in the head of the request list.
258  */
259 void ide_retry_pc(ide_drive_t *drive, struct gendisk *disk)
260 {
261         struct request *rq = &drive->request_sense_rq;
262         struct ide_atapi_pc *pc = &drive->request_sense_pc;
263
264         (void)ide_read_error(drive);
265         ide_create_request_sense_cmd(drive, pc);
266         if (drive->media == ide_tape)
267                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
268         ide_queue_pc_head(drive, disk, pc, rq);
269 }
270 EXPORT_SYMBOL_GPL(ide_retry_pc);
271
272 int ide_cd_expiry(ide_drive_t *drive)
273 {
274         struct request *rq = drive->hwif->rq;
275         unsigned long wait = 0;
276
277         debug_log("%s: rq->cmd[0]: 0x%x\n", __func__, rq->cmd[0]);
278
279         /*
280          * Some commands are *slow* and normally take a long time to complete.
281          * Usually we can use the ATAPI "disconnect" to bypass this, but not all
282          * commands/drives support that. Let ide_timer_expiry keep polling us
283          * for these.
284          */
285         switch (rq->cmd[0]) {
286         case GPCMD_BLANK:
287         case GPCMD_FORMAT_UNIT:
288         case GPCMD_RESERVE_RZONE_TRACK:
289         case GPCMD_CLOSE_TRACK:
290         case GPCMD_FLUSH_CACHE:
291                 wait = ATAPI_WAIT_PC;
292                 break;
293         default:
294                 if (!(rq->cmd_flags & REQ_QUIET))
295                         printk(KERN_INFO "cmd 0x%x timed out\n",
296                                          rq->cmd[0]);
297                 wait = 0;
298                 break;
299         }
300         return wait;
301 }
302 EXPORT_SYMBOL_GPL(ide_cd_expiry);
303
304 int ide_cd_get_xferlen(struct request *rq)
305 {
306         if (blk_fs_request(rq))
307                 return 32768;
308         else if (blk_sense_request(rq) || blk_pc_request(rq) ||
309                          rq->cmd_type == REQ_TYPE_ATA_PC)
310                 return rq->data_len;
311         else
312                 return 0;
313 }
314 EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
315
316 void ide_read_bcount_and_ireason(ide_drive_t *drive, u16 *bcount, u8 *ireason)
317 {
318         struct ide_taskfile tf;
319
320         drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_NSECT |
321                                      IDE_VALID_LBAM | IDE_VALID_LBAH);
322
323         *bcount = (tf.lbah << 8) | tf.lbam;
324         *ireason = tf.nsect & 3;
325 }
326 EXPORT_SYMBOL_GPL(ide_read_bcount_and_ireason);
327
328 /*
329  * This is the usual interrupt handler which will be called during a packet
330  * command.  We will transfer some of the data (as requested by the drive)
331  * and will re-point interrupt handler to us.
332  */
333 static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
334 {
335         struct ide_atapi_pc *pc = drive->pc;
336         ide_hwif_t *hwif = drive->hwif;
337         struct ide_cmd *cmd = &hwif->cmd;
338         struct request *rq = hwif->rq;
339         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
340         xfer_func_t *xferfunc;
341         unsigned int timeout, done;
342         u16 bcount;
343         u8 stat, ireason, dsc = 0;
344         u8 write = !!(pc->flags & PC_FLAG_WRITING);
345
346         debug_log("Enter %s - interrupt handler\n", __func__);
347
348         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
349                                                : WAIT_TAPE_CMD;
350
351         /* Clear the interrupt */
352         stat = tp_ops->read_status(hwif);
353
354         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
355                 int rc;
356
357                 drive->waiting_for_dma = 0;
358                 rc = hwif->dma_ops->dma_end(drive);
359                 ide_dma_unmap_sg(drive, cmd);
360
361                 if (rc || (drive->media == ide_tape && (stat & ATA_ERR))) {
362                         if (drive->media == ide_floppy)
363                                 printk(KERN_ERR "%s: DMA %s error\n",
364                                         drive->name, rq_data_dir(pc->rq)
365                                                      ? "write" : "read");
366                         pc->flags |= PC_FLAG_DMA_ERROR;
367                 } else {
368                         pc->xferred = pc->req_xfer;
369                         if (drive->pc_update_buffers)
370                                 drive->pc_update_buffers(drive, pc);
371                 }
372                 debug_log("%s: DMA finished\n", drive->name);
373         }
374
375         /* No more interrupts */
376         if ((stat & ATA_DRQ) == 0) {
377                 int uptodate, error;
378                 unsigned int done;
379
380                 debug_log("Packet command completed, %d bytes transferred\n",
381                           pc->xferred);
382
383                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
384
385                 local_irq_enable_in_hardirq();
386
387                 if (drive->media == ide_tape &&
388                     (stat & ATA_ERR) && rq->cmd[0] == REQUEST_SENSE)
389                         stat &= ~ATA_ERR;
390
391                 if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
392                         /* Error detected */
393                         debug_log("%s: I/O error\n", drive->name);
394
395                         if (drive->media != ide_tape)
396                                 pc->rq->errors++;
397
398                         if (rq->cmd[0] == REQUEST_SENSE) {
399                                 printk(KERN_ERR "%s: I/O error in request sense"
400                                                 " command\n", drive->name);
401                                 return ide_do_reset(drive);
402                         }
403
404                         debug_log("[cmd %x]: check condition\n", rq->cmd[0]);
405
406                         /* Retry operation */
407                         ide_retry_pc(drive, rq->rq_disk);
408
409                         /* queued, but not started */
410                         return ide_stopped;
411                 }
412                 pc->error = 0;
413
414                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
415                         dsc = 1;
416
417                 /* Command finished - Call the callback function */
418                 uptodate = drive->pc_callback(drive, dsc);
419
420                 if (uptodate == 0)
421                         drive->failed_pc = NULL;
422
423                 if (blk_special_request(rq)) {
424                         rq->errors = 0;
425                         done = blk_rq_bytes(rq);
426                         error = 0;
427                 } else {
428
429                         if (blk_fs_request(rq) == 0 && uptodate <= 0) {
430                                 if (rq->errors == 0)
431                                         rq->errors = -EIO;
432                         }
433
434                         if (drive->media == ide_tape)
435                                 done = ide_rq_bytes(rq); /* FIXME */
436                         else
437                                 done = blk_rq_bytes(rq);
438
439                         error = uptodate ? 0 : -EIO;
440                 }
441
442                 ide_complete_rq(drive, error, done);
443                 return ide_stopped;
444         }
445
446         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
447                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
448                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
449                                 "in DMA mode\n", drive->name);
450                 ide_dma_off(drive);
451                 return ide_do_reset(drive);
452         }
453
454         /* Get the number of bytes to transfer on this interrupt. */
455         ide_read_bcount_and_ireason(drive, &bcount, &ireason);
456
457         if (ireason & ATAPI_COD) {
458                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
459                 return ide_do_reset(drive);
460         }
461
462         if (((ireason & ATAPI_IO) == ATAPI_IO) == write) {
463                 /* Hopefully, we will never get here */
464                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
465                                 "to %s!\n", drive->name,
466                                 (ireason & ATAPI_IO) ? "Write" : "Read",
467                                 (ireason & ATAPI_IO) ? "Read" : "Write");
468                 return ide_do_reset(drive);
469         }
470
471         xferfunc = write ? tp_ops->output_data : tp_ops->input_data;
472
473         if (drive->media == ide_floppy && pc->buf == NULL) {
474                 done = min_t(unsigned int, bcount, cmd->nleft);
475                 ide_pio_bytes(drive, cmd, write, done);
476         } else if (drive->media == ide_tape && pc->bh) {
477                 done = drive->pc_io_buffers(drive, pc, bcount, write);
478         } else {
479                 done = min_t(unsigned int, bcount, pc->req_xfer - pc->xferred);
480                 xferfunc(drive, NULL, pc->cur_pos, done);
481         }
482
483         /* Update the current position */
484         pc->xferred += done;
485         pc->cur_pos += done;
486
487         bcount -= done;
488
489         if (bcount)
490                 ide_pad_transfer(drive, write, bcount);
491
492         debug_log("[cmd %x] transferred %d bytes, padded %d bytes\n",
493                   rq->cmd[0], done, bcount);
494
495         /* And set the interrupt handler again */
496         ide_set_handler(drive, ide_pc_intr, timeout);
497         return ide_started;
498 }
499
500 static void ide_init_packet_cmd(struct ide_cmd *cmd, u8 valid_tf,
501                                 u16 bcount, u8 dma)
502 {
503         cmd->protocol = dma ? ATAPI_PROT_DMA : ATAPI_PROT_PIO;
504         cmd->valid.out.tf = IDE_VALID_LBAH | IDE_VALID_LBAM |
505                             IDE_VALID_FEATURE | valid_tf;
506         cmd->tf.command = ATA_CMD_PACKET;
507         cmd->tf.feature = dma;          /* Use PIO/DMA */
508         cmd->tf.lbam    = bcount & 0xff;
509         cmd->tf.lbah    = (bcount >> 8) & 0xff;
510 }
511
512 static u8 ide_read_ireason(ide_drive_t *drive)
513 {
514         struct ide_taskfile tf;
515
516         drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_NSECT);
517
518         return tf.nsect & 3;
519 }
520
521 static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
522 {
523         int retries = 100;
524
525         while (retries-- && ((ireason & ATAPI_COD) == 0 ||
526                 (ireason & ATAPI_IO))) {
527                 printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
528                                 "a packet command, retrying\n", drive->name);
529                 udelay(100);
530                 ireason = ide_read_ireason(drive);
531                 if (retries == 0) {
532                         printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
533                                         "a packet command, ignoring\n",
534                                         drive->name);
535                         ireason |= ATAPI_COD;
536                         ireason &= ~ATAPI_IO;
537                 }
538         }
539
540         return ireason;
541 }
542
543 static int ide_delayed_transfer_pc(ide_drive_t *drive)
544 {
545         /* Send the actual packet */
546         drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);
547
548         /* Timeout for the packet command */
549         return WAIT_FLOPPY_CMD;
550 }
551
552 static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
553 {
554         struct ide_atapi_pc *uninitialized_var(pc);
555         ide_hwif_t *hwif = drive->hwif;
556         struct request *rq = hwif->rq;
557         ide_expiry_t *expiry;
558         unsigned int timeout;
559         int cmd_len;
560         ide_startstop_t startstop;
561         u8 ireason;
562
563         if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
564                 printk(KERN_ERR "%s: Strange, packet command initiated yet "
565                                 "DRQ isn't asserted\n", drive->name);
566                 return startstop;
567         }
568
569         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
570                 if (drive->dma)
571                         drive->waiting_for_dma = 1;
572         }
573
574         if (dev_is_idecd(drive)) {
575                 /* ATAPI commands get padded out to 12 bytes minimum */
576                 cmd_len = COMMAND_SIZE(rq->cmd[0]);
577                 if (cmd_len < ATAPI_MIN_CDB_BYTES)
578                         cmd_len = ATAPI_MIN_CDB_BYTES;
579
580                 timeout = rq->timeout;
581                 expiry  = ide_cd_expiry;
582         } else {
583                 pc = drive->pc;
584
585                 cmd_len = ATAPI_MIN_CDB_BYTES;
586
587                 /*
588                  * If necessary schedule the packet transfer to occur 'timeout'
589                  * miliseconds later in ide_delayed_transfer_pc() after the
590                  * device says it's ready for a packet.
591                  */
592                 if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
593                         timeout = drive->pc_delay;
594                         expiry = &ide_delayed_transfer_pc;
595                 } else {
596                         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
597                                                                : WAIT_TAPE_CMD;
598                         expiry = NULL;
599                 }
600
601                 ireason = ide_read_ireason(drive);
602                 if (drive->media == ide_tape)
603                         ireason = ide_wait_ireason(drive, ireason);
604
605                 if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
606                         printk(KERN_ERR "%s: (IO,CoD) != (0,1) while issuing "
607                                         "a packet command\n", drive->name);
608
609                         return ide_do_reset(drive);
610                 }
611         }
612
613         hwif->expiry = expiry;
614
615         /* Set the interrupt routine */
616         ide_set_handler(drive,
617                         (dev_is_idecd(drive) ? drive->irq_handler
618                                              : ide_pc_intr),
619                         timeout);
620
621         /* Send the actual packet */
622         if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
623                 hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
624
625         /* Begin DMA, if necessary */
626         if (dev_is_idecd(drive)) {
627                 if (drive->dma)
628                         hwif->dma_ops->dma_start(drive);
629         } else {
630                 if (pc->flags & PC_FLAG_DMA_OK) {
631                         pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
632                         hwif->dma_ops->dma_start(drive);
633                 }
634         }
635
636         return ide_started;
637 }
638
639 ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
640 {
641         struct ide_atapi_pc *pc;
642         ide_hwif_t *hwif = drive->hwif;
643         ide_expiry_t *expiry = NULL;
644         struct request *rq = hwif->rq;
645         unsigned int timeout;
646         u16 bcount;
647         u8 valid_tf;
648         u8 drq_int = !!(drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT);
649
650         if (dev_is_idecd(drive)) {
651                 valid_tf = IDE_VALID_NSECT | IDE_VALID_LBAL;
652                 bcount = ide_cd_get_xferlen(rq);
653                 expiry = ide_cd_expiry;
654                 timeout = ATAPI_WAIT_PC;
655
656                 if (drive->dma)
657                         drive->dma = !ide_dma_prepare(drive, cmd);
658         } else {
659                 pc = drive->pc;
660
661                 /* We haven't transferred any data yet */
662                 pc->xferred = 0;
663                 pc->cur_pos = pc->buf;
664
665                 valid_tf = IDE_VALID_DEVICE;
666                 bcount = ((drive->media == ide_tape) ?
667                                 pc->req_xfer :
668                                 min(pc->req_xfer, 63 * 1024));
669
670                 if (pc->flags & PC_FLAG_DMA_ERROR) {
671                         pc->flags &= ~PC_FLAG_DMA_ERROR;
672                         ide_dma_off(drive);
673                 }
674
675                 if (pc->flags & PC_FLAG_DMA_OK)
676                         drive->dma = !ide_dma_prepare(drive, cmd);
677
678                 if (!drive->dma)
679                         pc->flags &= ~PC_FLAG_DMA_OK;
680
681                 timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
682                                                        : WAIT_TAPE_CMD;
683         }
684
685         ide_init_packet_cmd(cmd, valid_tf, bcount, drive->dma);
686
687         (void)do_rw_taskfile(drive, cmd);
688
689         if (drq_int) {
690                 if (drive->dma)
691                         drive->waiting_for_dma = 0;
692                 hwif->expiry = expiry;
693         }
694
695         ide_execute_command(drive, cmd, ide_transfer_pc, timeout);
696
697         return drq_int ? ide_started : ide_transfer_pc(drive);
698 }
699 EXPORT_SYMBOL_GPL(ide_issue_pc);