ide/ata: Add export.h for EXPORT_SYMBOL/THIS_MODULE where needed
[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/export.h>
9 #include <linux/ide.h>
10 #include <linux/scatterlist.h>
11 #include <linux/gfp.h>
12
13 #include <scsi/scsi.h>
14
15 #define DRV_NAME "ide-atapi"
16 #define PFX DRV_NAME ": "
17
18 #ifdef DEBUG
19 #define debug_log(fmt, args...) \
20         printk(KERN_INFO "ide: " fmt, ## args)
21 #else
22 #define debug_log(fmt, args...) do {} while (0)
23 #endif
24
25 #define ATAPI_MIN_CDB_BYTES     12
26
27 static inline int dev_is_idecd(ide_drive_t *drive)
28 {
29         return drive->media == ide_cdrom || drive->media == ide_optical;
30 }
31
32 /*
33  * Check whether we can support a device,
34  * based on the ATAPI IDENTIFY command results.
35  */
36 int ide_check_atapi_device(ide_drive_t *drive, const char *s)
37 {
38         u16 *id = drive->id;
39         u8 gcw[2], protocol, device_type, removable, drq_type, packet_size;
40
41         *((u16 *)&gcw) = id[ATA_ID_CONFIG];
42
43         protocol    = (gcw[1] & 0xC0) >> 6;
44         device_type =  gcw[1] & 0x1F;
45         removable   = (gcw[0] & 0x80) >> 7;
46         drq_type    = (gcw[0] & 0x60) >> 5;
47         packet_size =  gcw[0] & 0x03;
48
49 #ifdef CONFIG_PPC
50         /* kludge for Apple PowerBook internal zip */
51         if (drive->media == ide_floppy && device_type == 5 &&
52             !strstr((char *)&id[ATA_ID_PROD], "CD-ROM") &&
53             strstr((char *)&id[ATA_ID_PROD], "ZIP"))
54                 device_type = 0;
55 #endif
56
57         if (protocol != 2)
58                 printk(KERN_ERR "%s: %s: protocol (0x%02x) is not ATAPI\n",
59                         s, drive->name, protocol);
60         else if ((drive->media == ide_floppy && device_type != 0) ||
61                  (drive->media == ide_tape && device_type != 1))
62                 printk(KERN_ERR "%s: %s: invalid device type (0x%02x)\n",
63                         s, drive->name, device_type);
64         else if (removable == 0)
65                 printk(KERN_ERR "%s: %s: the removable flag is not set\n",
66                         s, drive->name);
67         else if (drive->media == ide_floppy && drq_type == 3)
68                 printk(KERN_ERR "%s: %s: sorry, DRQ type (0x%02x) not "
69                         "supported\n", s, drive->name, drq_type);
70         else if (packet_size != 0)
71                 printk(KERN_ERR "%s: %s: packet size (0x%02x) is not 12 "
72                         "bytes\n", s, drive->name, packet_size);
73         else
74                 return 1;
75         return 0;
76 }
77 EXPORT_SYMBOL_GPL(ide_check_atapi_device);
78
79 void ide_init_pc(struct ide_atapi_pc *pc)
80 {
81         memset(pc, 0, sizeof(*pc));
82 }
83 EXPORT_SYMBOL_GPL(ide_init_pc);
84
85 /*
86  * Add a special packet command request to the tail of the request queue,
87  * and wait for it to be serviced.
88  */
89 int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
90                       struct ide_atapi_pc *pc, void *buf, unsigned int bufflen)
91 {
92         struct request *rq;
93         int error;
94
95         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
96         rq->cmd_type = REQ_TYPE_SPECIAL;
97         rq->special = (char *)pc;
98
99         if (buf && bufflen) {
100                 error = blk_rq_map_kern(drive->queue, rq, buf, bufflen,
101                                         GFP_NOIO);
102                 if (error)
103                         goto put_req;
104         }
105
106         memcpy(rq->cmd, pc->c, 12);
107         if (drive->media == ide_tape)
108                 rq->cmd[13] = REQ_IDETAPE_PC1;
109         error = blk_execute_rq(drive->queue, disk, rq, 0);
110 put_req:
111         blk_put_request(rq);
112         return error;
113 }
114 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
115
116 int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
117 {
118         struct ide_atapi_pc pc;
119
120         ide_init_pc(&pc);
121         pc.c[0] = TEST_UNIT_READY;
122
123         return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
124 }
125 EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);
126
127 int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
128 {
129         struct ide_atapi_pc pc;
130
131         ide_init_pc(&pc);
132         pc.c[0] = START_STOP;
133         pc.c[4] = start;
134
135         if (drive->media == ide_tape)
136                 pc.flags |= PC_FLAG_WAIT_FOR_DSC;
137
138         return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
139 }
140 EXPORT_SYMBOL_GPL(ide_do_start_stop);
141
142 int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
143 {
144         struct ide_atapi_pc pc;
145
146         if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
147                 return 0;
148
149         ide_init_pc(&pc);
150         pc.c[0] = ALLOW_MEDIUM_REMOVAL;
151         pc.c[4] = on;
152
153         return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
154 }
155 EXPORT_SYMBOL_GPL(ide_set_media_lock);
156
157 void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
158 {
159         ide_init_pc(pc);
160         pc->c[0] = REQUEST_SENSE;
161         if (drive->media == ide_floppy) {
162                 pc->c[4] = 255;
163                 pc->req_xfer = 18;
164         } else {
165                 pc->c[4] = 20;
166                 pc->req_xfer = 20;
167         }
168 }
169 EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);
170
171 void ide_prep_sense(ide_drive_t *drive, struct request *rq)
172 {
173         struct request_sense *sense = &drive->sense_data;
174         struct request *sense_rq = &drive->sense_rq;
175         unsigned int cmd_len, sense_len;
176         int err;
177
178         switch (drive->media) {
179         case ide_floppy:
180                 cmd_len = 255;
181                 sense_len = 18;
182                 break;
183         case ide_tape:
184                 cmd_len = 20;
185                 sense_len = 20;
186                 break;
187         default:
188                 cmd_len = 18;
189                 sense_len = 18;
190         }
191
192         BUG_ON(sense_len > sizeof(*sense));
193
194         if (rq->cmd_type == REQ_TYPE_SENSE || drive->sense_rq_armed)
195                 return;
196
197         memset(sense, 0, sizeof(*sense));
198
199         blk_rq_init(rq->q, sense_rq);
200
201         err = blk_rq_map_kern(drive->queue, sense_rq, sense, sense_len,
202                               GFP_NOIO);
203         if (unlikely(err)) {
204                 if (printk_ratelimit())
205                         printk(KERN_WARNING PFX "%s: failed to map sense "
206                                             "buffer\n", drive->name);
207                 return;
208         }
209
210         sense_rq->rq_disk = rq->rq_disk;
211         sense_rq->cmd[0] = GPCMD_REQUEST_SENSE;
212         sense_rq->cmd[4] = cmd_len;
213         sense_rq->cmd_type = REQ_TYPE_SENSE;
214         sense_rq->cmd_flags |= REQ_PREEMPT;
215
216         if (drive->media == ide_tape)
217                 sense_rq->cmd[13] = REQ_IDETAPE_PC1;
218
219         drive->sense_rq_armed = true;
220 }
221 EXPORT_SYMBOL_GPL(ide_prep_sense);
222
223 int ide_queue_sense_rq(ide_drive_t *drive, void *special)
224 {
225         /* deferred failure from ide_prep_sense() */
226         if (!drive->sense_rq_armed) {
227                 printk(KERN_WARNING PFX "%s: error queuing a sense request\n",
228                        drive->name);
229                 return -ENOMEM;
230         }
231
232         drive->sense_rq.special = special;
233         drive->sense_rq_armed = false;
234
235         drive->hwif->rq = NULL;
236
237         elv_add_request(drive->queue, &drive->sense_rq, ELEVATOR_INSERT_FRONT);
238         return 0;
239 }
240 EXPORT_SYMBOL_GPL(ide_queue_sense_rq);
241
242 /*
243  * Called when an error was detected during the last packet command.
244  * We queue a request sense packet command at the head of the request
245  * queue.
246  */
247 void ide_retry_pc(ide_drive_t *drive)
248 {
249         struct request *failed_rq = drive->hwif->rq;
250         struct request *sense_rq = &drive->sense_rq;
251         struct ide_atapi_pc *pc = &drive->request_sense_pc;
252
253         (void)ide_read_error(drive);
254
255         /* init pc from sense_rq */
256         ide_init_pc(pc);
257         memcpy(pc->c, sense_rq->cmd, 12);
258
259         if (drive->media == ide_tape)
260                 drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;
261
262         /*
263          * Push back the failed request and put request sense on top
264          * of it.  The failed command will be retried after sense data
265          * is acquired.
266          */
267         drive->hwif->rq = NULL;
268         ide_requeue_and_plug(drive, failed_rq);
269         if (ide_queue_sense_rq(drive, pc)) {
270                 blk_start_request(failed_rq);
271                 ide_complete_rq(drive, -EIO, blk_rq_bytes(failed_rq));
272         }
273 }
274 EXPORT_SYMBOL_GPL(ide_retry_pc);
275
276 int ide_cd_expiry(ide_drive_t *drive)
277 {
278         struct request *rq = drive->hwif->rq;
279         unsigned long wait = 0;
280
281         debug_log("%s: rq->cmd[0]: 0x%x\n", __func__, rq->cmd[0]);
282
283         /*
284          * Some commands are *slow* and normally take a long time to complete.
285          * Usually we can use the ATAPI "disconnect" to bypass this, but not all
286          * commands/drives support that. Let ide_timer_expiry keep polling us
287          * for these.
288          */
289         switch (rq->cmd[0]) {
290         case GPCMD_BLANK:
291         case GPCMD_FORMAT_UNIT:
292         case GPCMD_RESERVE_RZONE_TRACK:
293         case GPCMD_CLOSE_TRACK:
294         case GPCMD_FLUSH_CACHE:
295                 wait = ATAPI_WAIT_PC;
296                 break;
297         default:
298                 if (!(rq->cmd_flags & REQ_QUIET))
299                         printk(KERN_INFO PFX "cmd 0x%x timed out\n",
300                                          rq->cmd[0]);
301                 wait = 0;
302                 break;
303         }
304         return wait;
305 }
306 EXPORT_SYMBOL_GPL(ide_cd_expiry);
307
308 int ide_cd_get_xferlen(struct request *rq)
309 {
310         switch (rq->cmd_type) {
311         case REQ_TYPE_FS:
312                 return 32768;
313         case REQ_TYPE_SENSE:
314         case REQ_TYPE_BLOCK_PC:
315         case REQ_TYPE_ATA_PC:
316                 return blk_rq_bytes(rq);
317         default:
318                 return 0;
319         }
320 }
321 EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
322
323 void ide_read_bcount_and_ireason(ide_drive_t *drive, u16 *bcount, u8 *ireason)
324 {
325         struct ide_taskfile tf;
326
327         drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_NSECT |
328                                      IDE_VALID_LBAM | IDE_VALID_LBAH);
329
330         *bcount = (tf.lbah << 8) | tf.lbam;
331         *ireason = tf.nsect & 3;
332 }
333 EXPORT_SYMBOL_GPL(ide_read_bcount_and_ireason);
334
335 /*
336  * Check the contents of the interrupt reason register and attempt to recover if
337  * there are problems.
338  *
339  * Returns:
340  * - 0 if everything's ok
341  * - 1 if the request has to be terminated.
342  */
343 int ide_check_ireason(ide_drive_t *drive, struct request *rq, int len,
344                       int ireason, int rw)
345 {
346         ide_hwif_t *hwif = drive->hwif;
347
348         debug_log("ireason: 0x%x, rw: 0x%x\n", ireason, rw);
349
350         if (ireason == (!rw << 1))
351                 return 0;
352         else if (ireason == (rw << 1)) {
353                 printk(KERN_ERR PFX "%s: %s: wrong transfer direction!\n",
354                                 drive->name, __func__);
355
356                 if (dev_is_idecd(drive))
357                         ide_pad_transfer(drive, rw, len);
358         } else if (!rw && ireason == ATAPI_COD) {
359                 if (dev_is_idecd(drive)) {
360                         /*
361                          * Some drives (ASUS) seem to tell us that status info
362                          * is available.  Just get it and ignore.
363                          */
364                         (void)hwif->tp_ops->read_status(hwif);
365                         return 0;
366                 }
367         } else {
368                 if (ireason & ATAPI_COD)
369                         printk(KERN_ERR PFX "%s: CoD != 0 in %s\n", drive->name,
370                                         __func__);
371
372                 /* drive wants a command packet, or invalid ireason... */
373                 printk(KERN_ERR PFX "%s: %s: bad interrupt reason 0x%02x\n",
374                                 drive->name, __func__, ireason);
375         }
376
377         if (dev_is_idecd(drive) && rq->cmd_type == REQ_TYPE_ATA_PC)
378                 rq->cmd_flags |= REQ_FAILED;
379
380         return 1;
381 }
382 EXPORT_SYMBOL_GPL(ide_check_ireason);
383
384 /*
385  * This is the usual interrupt handler which will be called during a packet
386  * command.  We will transfer some of the data (as requested by the drive)
387  * and will re-point interrupt handler to us.
388  */
389 static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
390 {
391         struct ide_atapi_pc *pc = drive->pc;
392         ide_hwif_t *hwif = drive->hwif;
393         struct ide_cmd *cmd = &hwif->cmd;
394         struct request *rq = hwif->rq;
395         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
396         unsigned int timeout, done;
397         u16 bcount;
398         u8 stat, ireason, dsc = 0;
399         u8 write = !!(pc->flags & PC_FLAG_WRITING);
400
401         debug_log("Enter %s - interrupt handler\n", __func__);
402
403         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
404                                                : WAIT_TAPE_CMD;
405
406         /* Clear the interrupt */
407         stat = tp_ops->read_status(hwif);
408
409         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
410                 int rc;
411
412                 drive->waiting_for_dma = 0;
413                 rc = hwif->dma_ops->dma_end(drive);
414                 ide_dma_unmap_sg(drive, cmd);
415
416                 if (rc || (drive->media == ide_tape && (stat & ATA_ERR))) {
417                         if (drive->media == ide_floppy)
418                                 printk(KERN_ERR PFX "%s: DMA %s error\n",
419                                         drive->name, rq_data_dir(pc->rq)
420                                                      ? "write" : "read");
421                         pc->flags |= PC_FLAG_DMA_ERROR;
422                 } else
423                         rq->resid_len = 0;
424                 debug_log("%s: DMA finished\n", drive->name);
425         }
426
427         /* No more interrupts */
428         if ((stat & ATA_DRQ) == 0) {
429                 int uptodate, error;
430
431                 debug_log("Packet command completed, %d bytes transferred\n",
432                           blk_rq_bytes(rq));
433
434                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
435
436                 local_irq_enable_in_hardirq();
437
438                 if (drive->media == ide_tape &&
439                     (stat & ATA_ERR) && rq->cmd[0] == REQUEST_SENSE)
440                         stat &= ~ATA_ERR;
441
442                 if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
443                         /* Error detected */
444                         debug_log("%s: I/O error\n", drive->name);
445
446                         if (drive->media != ide_tape)
447                                 pc->rq->errors++;
448
449                         if (rq->cmd[0] == REQUEST_SENSE) {
450                                 printk(KERN_ERR PFX "%s: I/O error in request "
451                                                 "sense command\n", drive->name);
452                                 return ide_do_reset(drive);
453                         }
454
455                         debug_log("[cmd %x]: check condition\n", rq->cmd[0]);
456
457                         /* Retry operation */
458                         ide_retry_pc(drive);
459
460                         /* queued, but not started */
461                         return ide_stopped;
462                 }
463                 pc->error = 0;
464
465                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
466                         dsc = 1;
467
468                 /*
469                  * ->pc_callback() might change rq->data_len for
470                  * residual count, cache total length.
471                  */
472                 done = blk_rq_bytes(rq);
473
474                 /* Command finished - Call the callback function */
475                 uptodate = drive->pc_callback(drive, dsc);
476
477                 if (uptodate == 0)
478                         drive->failed_pc = NULL;
479
480                 if (rq->cmd_type == REQ_TYPE_SPECIAL) {
481                         rq->errors = 0;
482                         error = 0;
483                 } else {
484
485                         if (rq->cmd_type != REQ_TYPE_FS && uptodate <= 0) {
486                                 if (rq->errors == 0)
487                                         rq->errors = -EIO;
488                         }
489
490                         error = uptodate ? 0 : -EIO;
491                 }
492
493                 ide_complete_rq(drive, error, blk_rq_bytes(rq));
494                 return ide_stopped;
495         }
496
497         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
498                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
499                 printk(KERN_ERR PFX "%s: The device wants to issue more "
500                                 "interrupts in DMA mode\n", drive->name);
501                 ide_dma_off(drive);
502                 return ide_do_reset(drive);
503         }
504
505         /* Get the number of bytes to transfer on this interrupt. */
506         ide_read_bcount_and_ireason(drive, &bcount, &ireason);
507
508         if (ide_check_ireason(drive, rq, bcount, ireason, write))
509                 return ide_do_reset(drive);
510
511         done = min_t(unsigned int, bcount, cmd->nleft);
512         ide_pio_bytes(drive, cmd, write, done);
513
514         /* Update transferred byte count */
515         rq->resid_len -= done;
516
517         bcount -= done;
518
519         if (bcount)
520                 ide_pad_transfer(drive, write, bcount);
521
522         debug_log("[cmd %x] transferred %d bytes, padded %d bytes, resid: %u\n",
523                   rq->cmd[0], done, bcount, rq->resid_len);
524
525         /* And set the interrupt handler again */
526         ide_set_handler(drive, ide_pc_intr, timeout);
527         return ide_started;
528 }
529
530 static void ide_init_packet_cmd(struct ide_cmd *cmd, u8 valid_tf,
531                                 u16 bcount, u8 dma)
532 {
533         cmd->protocol = dma ? ATAPI_PROT_DMA : ATAPI_PROT_PIO;
534         cmd->valid.out.tf = IDE_VALID_LBAH | IDE_VALID_LBAM |
535                             IDE_VALID_FEATURE | valid_tf;
536         cmd->tf.command = ATA_CMD_PACKET;
537         cmd->tf.feature = dma;          /* Use PIO/DMA */
538         cmd->tf.lbam    = bcount & 0xff;
539         cmd->tf.lbah    = (bcount >> 8) & 0xff;
540 }
541
542 static u8 ide_read_ireason(ide_drive_t *drive)
543 {
544         struct ide_taskfile tf;
545
546         drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_NSECT);
547
548         return tf.nsect & 3;
549 }
550
551 static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
552 {
553         int retries = 100;
554
555         while (retries-- && ((ireason & ATAPI_COD) == 0 ||
556                 (ireason & ATAPI_IO))) {
557                 printk(KERN_ERR PFX "%s: (IO,CoD != (0,1) while issuing "
558                                 "a packet command, retrying\n", drive->name);
559                 udelay(100);
560                 ireason = ide_read_ireason(drive);
561                 if (retries == 0) {
562                         printk(KERN_ERR PFX "%s: (IO,CoD != (0,1) while issuing"
563                                         " a packet command, ignoring\n",
564                                         drive->name);
565                         ireason |= ATAPI_COD;
566                         ireason &= ~ATAPI_IO;
567                 }
568         }
569
570         return ireason;
571 }
572
573 static int ide_delayed_transfer_pc(ide_drive_t *drive)
574 {
575         /* Send the actual packet */
576         drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);
577
578         /* Timeout for the packet command */
579         return WAIT_FLOPPY_CMD;
580 }
581
582 static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
583 {
584         struct ide_atapi_pc *uninitialized_var(pc);
585         ide_hwif_t *hwif = drive->hwif;
586         struct request *rq = hwif->rq;
587         ide_expiry_t *expiry;
588         unsigned int timeout;
589         int cmd_len;
590         ide_startstop_t startstop;
591         u8 ireason;
592
593         if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
594                 printk(KERN_ERR PFX "%s: Strange, packet command initiated yet "
595                                 "DRQ isn't asserted\n", drive->name);
596                 return startstop;
597         }
598
599         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
600                 if (drive->dma)
601                         drive->waiting_for_dma = 1;
602         }
603
604         if (dev_is_idecd(drive)) {
605                 /* ATAPI commands get padded out to 12 bytes minimum */
606                 cmd_len = COMMAND_SIZE(rq->cmd[0]);
607                 if (cmd_len < ATAPI_MIN_CDB_BYTES)
608                         cmd_len = ATAPI_MIN_CDB_BYTES;
609
610                 timeout = rq->timeout;
611                 expiry  = ide_cd_expiry;
612         } else {
613                 pc = drive->pc;
614
615                 cmd_len = ATAPI_MIN_CDB_BYTES;
616
617                 /*
618                  * If necessary schedule the packet transfer to occur 'timeout'
619                  * milliseconds later in ide_delayed_transfer_pc() after the
620                  * device says it's ready for a packet.
621                  */
622                 if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
623                         timeout = drive->pc_delay;
624                         expiry = &ide_delayed_transfer_pc;
625                 } else {
626                         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
627                                                                : WAIT_TAPE_CMD;
628                         expiry = NULL;
629                 }
630
631                 ireason = ide_read_ireason(drive);
632                 if (drive->media == ide_tape)
633                         ireason = ide_wait_ireason(drive, ireason);
634
635                 if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
636                         printk(KERN_ERR PFX "%s: (IO,CoD) != (0,1) while "
637                                 "issuing a packet command\n", drive->name);
638
639                         return ide_do_reset(drive);
640                 }
641         }
642
643         hwif->expiry = expiry;
644
645         /* Set the interrupt routine */
646         ide_set_handler(drive,
647                         (dev_is_idecd(drive) ? drive->irq_handler
648                                              : ide_pc_intr),
649                         timeout);
650
651         /* Send the actual packet */
652         if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
653                 hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
654
655         /* Begin DMA, if necessary */
656         if (dev_is_idecd(drive)) {
657                 if (drive->dma)
658                         hwif->dma_ops->dma_start(drive);
659         } else {
660                 if (pc->flags & PC_FLAG_DMA_OK) {
661                         pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
662                         hwif->dma_ops->dma_start(drive);
663                 }
664         }
665
666         return ide_started;
667 }
668
669 ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
670 {
671         struct ide_atapi_pc *pc;
672         ide_hwif_t *hwif = drive->hwif;
673         ide_expiry_t *expiry = NULL;
674         struct request *rq = hwif->rq;
675         unsigned int timeout, bytes;
676         u16 bcount;
677         u8 valid_tf;
678         u8 drq_int = !!(drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT);
679
680         if (dev_is_idecd(drive)) {
681                 valid_tf = IDE_VALID_NSECT | IDE_VALID_LBAL;
682                 bcount = ide_cd_get_xferlen(rq);
683                 expiry = ide_cd_expiry;
684                 timeout = ATAPI_WAIT_PC;
685
686                 if (drive->dma)
687                         drive->dma = !ide_dma_prepare(drive, cmd);
688         } else {
689                 pc = drive->pc;
690
691                 valid_tf = IDE_VALID_DEVICE;
692                 bytes = blk_rq_bytes(rq);
693                 bcount = ((drive->media == ide_tape) ? bytes
694                                                      : min_t(unsigned int,
695                                                              bytes, 63 * 1024));
696
697                 /* We haven't transferred any data yet */
698                 rq->resid_len = bcount;
699
700                 if (pc->flags & PC_FLAG_DMA_ERROR) {
701                         pc->flags &= ~PC_FLAG_DMA_ERROR;
702                         ide_dma_off(drive);
703                 }
704
705                 if (pc->flags & PC_FLAG_DMA_OK)
706                         drive->dma = !ide_dma_prepare(drive, cmd);
707
708                 if (!drive->dma)
709                         pc->flags &= ~PC_FLAG_DMA_OK;
710
711                 timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
712                                                        : WAIT_TAPE_CMD;
713         }
714
715         ide_init_packet_cmd(cmd, valid_tf, bcount, drive->dma);
716
717         (void)do_rw_taskfile(drive, cmd);
718
719         if (drq_int) {
720                 if (drive->dma)
721                         drive->waiting_for_dma = 0;
722                 hwif->expiry = expiry;
723         }
724
725         ide_execute_command(drive, cmd, ide_transfer_pc, timeout);
726
727         return drq_int ? ide_started : ide_transfer_pc(drive);
728 }
729 EXPORT_SYMBOL_GPL(ide_issue_pc);