ide: return request status from ->pc_callback method
[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 <scsi/scsi.h>
10
11 #ifdef DEBUG
12 #define debug_log(fmt, args...) \
13         printk(KERN_INFO "ide: " fmt, ## args)
14 #else
15 #define debug_log(fmt, args...) do {} while (0)
16 #endif
17
18 #define ATAPI_MIN_CDB_BYTES     12
19
20 static inline int dev_is_idecd(ide_drive_t *drive)
21 {
22         return drive->media == ide_cdrom || drive->media == ide_optical;
23 }
24
25 /*
26  * Check whether we can support a device,
27  * based on the ATAPI IDENTIFY command results.
28  */
29 int ide_check_atapi_device(ide_drive_t *drive, const char *s)
30 {
31         u16 *id = drive->id;
32         u8 gcw[2], protocol, device_type, removable, drq_type, packet_size;
33
34         *((u16 *)&gcw) = id[ATA_ID_CONFIG];
35
36         protocol    = (gcw[1] & 0xC0) >> 6;
37         device_type =  gcw[1] & 0x1F;
38         removable   = (gcw[0] & 0x80) >> 7;
39         drq_type    = (gcw[0] & 0x60) >> 5;
40         packet_size =  gcw[0] & 0x03;
41
42 #ifdef CONFIG_PPC
43         /* kludge for Apple PowerBook internal zip */
44         if (drive->media == ide_floppy && device_type == 5 &&
45             !strstr((char *)&id[ATA_ID_PROD], "CD-ROM") &&
46             strstr((char *)&id[ATA_ID_PROD], "ZIP"))
47                 device_type = 0;
48 #endif
49
50         if (protocol != 2)
51                 printk(KERN_ERR "%s: %s: protocol (0x%02x) is not ATAPI\n",
52                         s, drive->name, protocol);
53         else if ((drive->media == ide_floppy && device_type != 0) ||
54                  (drive->media == ide_tape && device_type != 1))
55                 printk(KERN_ERR "%s: %s: invalid device type (0x%02x)\n",
56                         s, drive->name, device_type);
57         else if (removable == 0)
58                 printk(KERN_ERR "%s: %s: the removable flag is not set\n",
59                         s, drive->name);
60         else if (drive->media == ide_floppy && drq_type == 3)
61                 printk(KERN_ERR "%s: %s: sorry, DRQ type (0x%02x) not "
62                         "supported\n", s, drive->name, drq_type);
63         else if (packet_size != 0)
64                 printk(KERN_ERR "%s: %s: packet size (0x%02x) is not 12 "
65                         "bytes\n", s, drive->name, packet_size);
66         else
67                 return 1;
68         return 0;
69 }
70 EXPORT_SYMBOL_GPL(ide_check_atapi_device);
71
72 /* PIO data transfer routine using the scatter gather table. */
73 int ide_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
74                     unsigned int bcount, int write)
75 {
76         ide_hwif_t *hwif = drive->hwif;
77         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
78         xfer_func_t *xf = write ? tp_ops->output_data : tp_ops->input_data;
79         struct scatterlist *sg = pc->sg;
80         char *buf;
81         int count, done = 0;
82
83         while (bcount) {
84                 count = min(sg->length - pc->b_count, bcount);
85
86                 if (PageHighMem(sg_page(sg))) {
87                         unsigned long flags;
88
89                         local_irq_save(flags);
90                         buf = kmap_atomic(sg_page(sg), KM_IRQ0) + sg->offset;
91                         xf(drive, NULL, buf + pc->b_count, count);
92                         kunmap_atomic(buf - sg->offset, KM_IRQ0);
93                         local_irq_restore(flags);
94                 } else {
95                         buf = sg_virt(sg);
96                         xf(drive, NULL, buf + pc->b_count, count);
97                 }
98
99                 bcount -= count;
100                 pc->b_count += count;
101                 done += count;
102
103                 if (pc->b_count == sg->length) {
104                         if (!--pc->sg_cnt)
105                                 break;
106                         pc->sg = sg = sg_next(sg);
107                         pc->b_count = 0;
108                 }
109         }
110
111         if (bcount) {
112                 printk(KERN_ERR "%s: %d leftover bytes, %s\n", drive->name,
113                         bcount, write ? "padding with zeros"
114                                       : "discarding data");
115                 ide_pad_transfer(drive, write, bcount);
116         }
117
118         return done;
119 }
120 EXPORT_SYMBOL_GPL(ide_io_buffers);
121
122 void ide_init_pc(struct ide_atapi_pc *pc)
123 {
124         memset(pc, 0, sizeof(*pc));
125         pc->buf = pc->pc_buf;
126         pc->buf_size = IDE_PC_BUFFER_SIZE;
127 }
128 EXPORT_SYMBOL_GPL(ide_init_pc);
129
130 /*
131  * Generate a new packet command request in front of the request queue, before
132  * the current request, so that it will be processed immediately, on the next
133  * pass through the driver.
134  */
135 static void ide_queue_pc_head(ide_drive_t *drive, struct gendisk *disk,
136                               struct ide_atapi_pc *pc, struct request *rq)
137 {
138         blk_rq_init(NULL, rq);
139         rq->cmd_type = REQ_TYPE_SPECIAL;
140         rq->cmd_flags |= REQ_PREEMPT;
141         rq->buffer = (char *)pc;
142         rq->rq_disk = disk;
143
144         if (pc->req_xfer) {
145                 rq->data = pc->buf;
146                 rq->data_len = pc->req_xfer;
147         }
148
149         memcpy(rq->cmd, pc->c, 12);
150         if (drive->media == ide_tape)
151                 rq->cmd[13] = REQ_IDETAPE_PC1;
152
153         drive->hwif->rq = NULL;
154
155         elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 0);
156 }
157
158 /*
159  * Add a special packet command request to the tail of the request queue,
160  * and wait for it to be serviced.
161  */
162 int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
163                       struct ide_atapi_pc *pc)
164 {
165         struct request *rq;
166         int error;
167
168         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
169         rq->cmd_type = REQ_TYPE_SPECIAL;
170         rq->buffer = (char *)pc;
171
172         if (pc->req_xfer) {
173                 rq->data = pc->buf;
174                 rq->data_len = pc->req_xfer;
175         }
176
177         memcpy(rq->cmd, pc->c, 12);
178         if (drive->media == ide_tape)
179                 rq->cmd[13] = REQ_IDETAPE_PC1;
180         error = blk_execute_rq(drive->queue, disk, rq, 0);
181         blk_put_request(rq);
182
183         return error;
184 }
185 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
186
187 int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
188 {
189         struct ide_atapi_pc pc;
190
191         ide_init_pc(&pc);
192         pc.c[0] = TEST_UNIT_READY;
193
194         return ide_queue_pc_tail(drive, disk, &pc);
195 }
196 EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);
197
198 int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
199 {
200         struct ide_atapi_pc pc;
201
202         ide_init_pc(&pc);
203         pc.c[0] = START_STOP;
204         pc.c[4] = start;
205
206         if (drive->media == ide_tape)
207                 pc.flags |= PC_FLAG_WAIT_FOR_DSC;
208
209         return ide_queue_pc_tail(drive, disk, &pc);
210 }
211 EXPORT_SYMBOL_GPL(ide_do_start_stop);
212
213 int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
214 {
215         struct ide_atapi_pc pc;
216
217         if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
218                 return 0;
219
220         ide_init_pc(&pc);
221         pc.c[0] = ALLOW_MEDIUM_REMOVAL;
222         pc.c[4] = on;
223
224         return ide_queue_pc_tail(drive, disk, &pc);
225 }
226 EXPORT_SYMBOL_GPL(ide_set_media_lock);
227
228 void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
229 {
230         ide_init_pc(pc);
231         pc->c[0] = REQUEST_SENSE;
232         if (drive->media == ide_floppy) {
233                 pc->c[4] = 255;
234                 pc->req_xfer = 18;
235         } else {
236                 pc->c[4] = 20;
237                 pc->req_xfer = 20;
238         }
239 }
240 EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);
241
242 /*
243  * Called when an error was detected during the last packet command.
244  * We queue a request sense packet command in the head of the request list.
245  */
246 void ide_retry_pc(ide_drive_t *drive, struct gendisk *disk)
247 {
248         struct request *rq = &drive->request_sense_rq;
249         struct ide_atapi_pc *pc = &drive->request_sense_pc;
250
251         (void)ide_read_error(drive);
252         ide_create_request_sense_cmd(drive, pc);
253         if (drive->media == ide_tape)
254                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
255         ide_queue_pc_head(drive, disk, pc, rq);
256 }
257 EXPORT_SYMBOL_GPL(ide_retry_pc);
258
259 int ide_cd_expiry(ide_drive_t *drive)
260 {
261         struct request *rq = drive->hwif->rq;
262         unsigned long wait = 0;
263
264         debug_log("%s: rq->cmd[0]: 0x%x\n", __func__, rq->cmd[0]);
265
266         /*
267          * Some commands are *slow* and normally take a long time to complete.
268          * Usually we can use the ATAPI "disconnect" to bypass this, but not all
269          * commands/drives support that. Let ide_timer_expiry keep polling us
270          * for these.
271          */
272         switch (rq->cmd[0]) {
273         case GPCMD_BLANK:
274         case GPCMD_FORMAT_UNIT:
275         case GPCMD_RESERVE_RZONE_TRACK:
276         case GPCMD_CLOSE_TRACK:
277         case GPCMD_FLUSH_CACHE:
278                 wait = ATAPI_WAIT_PC;
279                 break;
280         default:
281                 if (!(rq->cmd_flags & REQ_QUIET))
282                         printk(KERN_INFO "cmd 0x%x timed out\n",
283                                          rq->cmd[0]);
284                 wait = 0;
285                 break;
286         }
287         return wait;
288 }
289 EXPORT_SYMBOL_GPL(ide_cd_expiry);
290
291 int ide_cd_get_xferlen(struct request *rq)
292 {
293         if (blk_fs_request(rq))
294                 return 32768;
295         else if (blk_sense_request(rq) || blk_pc_request(rq) ||
296                          rq->cmd_type == REQ_TYPE_ATA_PC)
297                 return rq->data_len;
298         else
299                 return 0;
300 }
301 EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
302
303 void ide_read_bcount_and_ireason(ide_drive_t *drive, u16 *bcount, u8 *ireason)
304 {
305         ide_task_t task;
306
307         memset(&task, 0, sizeof(task));
308         task.tf_flags = IDE_TFLAG_IN_LBAH | IDE_TFLAG_IN_LBAM |
309                         IDE_TFLAG_IN_NSECT;
310
311         drive->hwif->tp_ops->tf_read(drive, &task);
312
313         *bcount = (task.tf.lbah << 8) | task.tf.lbam;
314         *ireason = task.tf.nsect & 3;
315 }
316 EXPORT_SYMBOL_GPL(ide_read_bcount_and_ireason);
317
318 /*
319  * This is the usual interrupt handler which will be called during a packet
320  * command.  We will transfer some of the data (as requested by the drive)
321  * and will re-point interrupt handler to us.
322  */
323 static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
324 {
325         struct ide_atapi_pc *pc = drive->pc;
326         ide_hwif_t *hwif = drive->hwif;
327         struct request *rq = hwif->rq;
328         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
329         xfer_func_t *xferfunc;
330         unsigned int timeout, temp;
331         u16 bcount;
332         u8 stat, ireason, dsc = 0;
333
334         debug_log("Enter %s - interrupt handler\n", __func__);
335
336         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
337                                                : WAIT_TAPE_CMD;
338
339         /* Clear the interrupt */
340         stat = tp_ops->read_status(hwif);
341
342         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
343                 if (hwif->dma_ops->dma_end(drive) ||
344                     (drive->media == ide_tape && (stat & ATA_ERR))) {
345                         if (drive->media == ide_floppy)
346                                 printk(KERN_ERR "%s: DMA %s error\n",
347                                         drive->name, rq_data_dir(pc->rq)
348                                                      ? "write" : "read");
349                         pc->flags |= PC_FLAG_DMA_ERROR;
350                 } else {
351                         pc->xferred = pc->req_xfer;
352                         if (drive->pc_update_buffers)
353                                 drive->pc_update_buffers(drive, pc);
354                 }
355                 debug_log("%s: DMA finished\n", drive->name);
356         }
357
358         /* No more interrupts */
359         if ((stat & ATA_DRQ) == 0) {
360                 int uptodate;
361
362                 debug_log("Packet command completed, %d bytes transferred\n",
363                           pc->xferred);
364
365                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
366
367                 local_irq_enable_in_hardirq();
368
369                 if (drive->media == ide_tape &&
370                     (stat & ATA_ERR) && rq->cmd[0] == REQUEST_SENSE)
371                         stat &= ~ATA_ERR;
372
373                 if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
374                         /* Error detected */
375                         debug_log("%s: I/O error\n", drive->name);
376
377                         if (drive->media != ide_tape)
378                                 pc->rq->errors++;
379
380                         if (rq->cmd[0] == REQUEST_SENSE) {
381                                 printk(KERN_ERR "%s: I/O error in request sense"
382                                                 " command\n", drive->name);
383                                 return ide_do_reset(drive);
384                         }
385
386                         debug_log("[cmd %x]: check condition\n", rq->cmd[0]);
387
388                         /* Retry operation */
389                         ide_retry_pc(drive, rq->rq_disk);
390
391                         /* queued, but not started */
392                         return ide_stopped;
393                 }
394                 pc->error = 0;
395
396                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
397                         dsc = 1;
398
399                 /* Command finished - Call the callback function */
400                 uptodate = drive->pc_callback(drive, dsc);
401
402                 if (uptodate == 0)
403                         drive->failed_pc = NULL;
404
405                 if (blk_special_request(rq))
406                         ide_complete_rq(drive, 0);
407                 else
408                         ide_end_request(drive, uptodate, 0);
409
410                 return ide_stopped;
411         }
412
413         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
414                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
415                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
416                                 "in DMA mode\n", drive->name);
417                 ide_dma_off(drive);
418                 return ide_do_reset(drive);
419         }
420
421         /* Get the number of bytes to transfer on this interrupt. */
422         ide_read_bcount_and_ireason(drive, &bcount, &ireason);
423
424         if (ireason & ATAPI_COD) {
425                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
426                 return ide_do_reset(drive);
427         }
428
429         if (((ireason & ATAPI_IO) == ATAPI_IO) ==
430                 !!(pc->flags & PC_FLAG_WRITING)) {
431                 /* Hopefully, we will never get here */
432                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
433                                 "to %s!\n", drive->name,
434                                 (ireason & ATAPI_IO) ? "Write" : "Read",
435                                 (ireason & ATAPI_IO) ? "Read" : "Write");
436                 return ide_do_reset(drive);
437         }
438
439         if (!(pc->flags & PC_FLAG_WRITING)) {
440                 /* Reading - Check that we have enough space */
441                 temp = pc->xferred + bcount;
442                 if (temp > pc->req_xfer) {
443                         if (temp > pc->buf_size) {
444                                 printk(KERN_ERR "%s: The device wants to send "
445                                                 "us more data than expected - "
446                                                 "discarding data\n",
447                                                 drive->name);
448
449                                 ide_pad_transfer(drive, 0, bcount);
450                                 goto next_irq;
451                         }
452                         debug_log("The device wants to send us more data than "
453                                   "expected - allowing transfer\n");
454                 }
455                 xferfunc = tp_ops->input_data;
456         } else
457                 xferfunc = tp_ops->output_data;
458
459         if ((drive->media == ide_floppy && !pc->buf) ||
460             (drive->media == ide_tape && pc->bh)) {
461                 int done = drive->pc_io_buffers(drive, pc, bcount,
462                                   !!(pc->flags & PC_FLAG_WRITING));
463
464                 /* FIXME: don't do partial completions */
465                 if (drive->media == ide_floppy)
466                         ide_end_request(drive, 1, done >> 9);
467         } else
468                 xferfunc(drive, NULL, pc->cur_pos, bcount);
469
470         /* Update the current position */
471         pc->xferred += bcount;
472         pc->cur_pos += bcount;
473
474         debug_log("[cmd %x] transferred %d bytes on that intr.\n",
475                   rq->cmd[0], bcount);
476 next_irq:
477         /* And set the interrupt handler again */
478         ide_set_handler(drive, ide_pc_intr, timeout, NULL);
479         return ide_started;
480 }
481
482 static void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount)
483 {
484         ide_hwif_t *hwif = drive->hwif;
485         ide_task_t task;
486         u8 dma = drive->dma;
487
488         memset(&task, 0, sizeof(task));
489         task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM |
490                         IDE_TFLAG_OUT_FEATURE | tf_flags;
491         task.tf.feature = dma;          /* Use PIO/DMA */
492         task.tf.lbam    = bcount & 0xff;
493         task.tf.lbah    = (bcount >> 8) & 0xff;
494
495         ide_tf_dump(drive->name, &task.tf);
496         hwif->tp_ops->set_irq(hwif, 1);
497         SELECT_MASK(drive, 0);
498         hwif->tp_ops->tf_load(drive, &task);
499 }
500
501 static u8 ide_read_ireason(ide_drive_t *drive)
502 {
503         ide_task_t task;
504
505         memset(&task, 0, sizeof(task));
506         task.tf_flags = IDE_TFLAG_IN_NSECT;
507
508         drive->hwif->tp_ops->tf_read(drive, &task);
509
510         return task.tf.nsect & 3;
511 }
512
513 static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
514 {
515         int retries = 100;
516
517         while (retries-- && ((ireason & ATAPI_COD) == 0 ||
518                 (ireason & ATAPI_IO))) {
519                 printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
520                                 "a packet command, retrying\n", drive->name);
521                 udelay(100);
522                 ireason = ide_read_ireason(drive);
523                 if (retries == 0) {
524                         printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
525                                         "a packet command, ignoring\n",
526                                         drive->name);
527                         ireason |= ATAPI_COD;
528                         ireason &= ~ATAPI_IO;
529                 }
530         }
531
532         return ireason;
533 }
534
535 static int ide_delayed_transfer_pc(ide_drive_t *drive)
536 {
537         /* Send the actual packet */
538         drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);
539
540         /* Timeout for the packet command */
541         return WAIT_FLOPPY_CMD;
542 }
543
544 static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
545 {
546         struct ide_atapi_pc *uninitialized_var(pc);
547         ide_hwif_t *hwif = drive->hwif;
548         struct request *rq = hwif->rq;
549         ide_expiry_t *expiry;
550         unsigned int timeout;
551         int cmd_len;
552         ide_startstop_t startstop;
553         u8 ireason;
554
555         if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
556                 printk(KERN_ERR "%s: Strange, packet command initiated yet "
557                                 "DRQ isn't asserted\n", drive->name);
558                 return startstop;
559         }
560
561         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
562                 if (drive->dma)
563                         drive->waiting_for_dma = 1;
564         }
565
566         if (dev_is_idecd(drive)) {
567                 /* ATAPI commands get padded out to 12 bytes minimum */
568                 cmd_len = COMMAND_SIZE(rq->cmd[0]);
569                 if (cmd_len < ATAPI_MIN_CDB_BYTES)
570                         cmd_len = ATAPI_MIN_CDB_BYTES;
571
572                 timeout = rq->timeout;
573                 expiry  = ide_cd_expiry;
574         } else {
575                 pc = drive->pc;
576
577                 cmd_len = ATAPI_MIN_CDB_BYTES;
578
579                 /*
580                  * If necessary schedule the packet transfer to occur 'timeout'
581                  * miliseconds later in ide_delayed_transfer_pc() after the
582                  * device says it's ready for a packet.
583                  */
584                 if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
585                         timeout = drive->pc_delay;
586                         expiry = &ide_delayed_transfer_pc;
587                 } else {
588                         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
589                                                                : WAIT_TAPE_CMD;
590                         expiry = NULL;
591                 }
592
593                 ireason = ide_read_ireason(drive);
594                 if (drive->media == ide_tape)
595                         ireason = ide_wait_ireason(drive, ireason);
596
597                 if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
598                         printk(KERN_ERR "%s: (IO,CoD) != (0,1) while issuing "
599                                         "a packet command\n", drive->name);
600
601                         return ide_do_reset(drive);
602                 }
603         }
604
605         /* Set the interrupt routine */
606         ide_set_handler(drive,
607                         (dev_is_idecd(drive) ? drive->irq_handler
608                                              : ide_pc_intr),
609                         timeout, expiry);
610
611         /* Begin DMA, if necessary */
612         if (dev_is_idecd(drive)) {
613                 if (drive->dma)
614                         hwif->dma_ops->dma_start(drive);
615         } else {
616                 if (pc->flags & PC_FLAG_DMA_OK) {
617                         pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
618                         hwif->dma_ops->dma_start(drive);
619                 }
620         }
621
622         /* Send the actual packet */
623         if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
624                 hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
625
626         return ide_started;
627 }
628
629 ide_startstop_t ide_issue_pc(ide_drive_t *drive)
630 {
631         struct ide_atapi_pc *pc;
632         ide_hwif_t *hwif = drive->hwif;
633         ide_expiry_t *expiry = NULL;
634         unsigned int timeout;
635         u32 tf_flags;
636         u16 bcount;
637
638         if (dev_is_idecd(drive)) {
639                 tf_flags = IDE_TFLAG_OUT_NSECT | IDE_TFLAG_OUT_LBAL;
640                 bcount = ide_cd_get_xferlen(hwif->rq);
641                 expiry = ide_cd_expiry;
642                 timeout = ATAPI_WAIT_PC;
643
644                 if (drive->dma)
645                         drive->dma = !hwif->dma_ops->dma_setup(drive);
646         } else {
647                 pc = drive->pc;
648
649                 /* We haven't transferred any data yet */
650                 pc->xferred = 0;
651                 pc->cur_pos = pc->buf;
652
653                 tf_flags = IDE_TFLAG_OUT_DEVICE;
654                 bcount = ((drive->media == ide_tape) ?
655                                 pc->req_xfer :
656                                 min(pc->req_xfer, 63 * 1024));
657
658                 if (pc->flags & PC_FLAG_DMA_ERROR) {
659                         pc->flags &= ~PC_FLAG_DMA_ERROR;
660                         ide_dma_off(drive);
661                 }
662
663                 if ((pc->flags & PC_FLAG_DMA_OK) &&
664                      (drive->dev_flags & IDE_DFLAG_USING_DMA))
665                         drive->dma = !hwif->dma_ops->dma_setup(drive);
666
667                 if (!drive->dma)
668                         pc->flags &= ~PC_FLAG_DMA_OK;
669
670                 timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
671                                                        : WAIT_TAPE_CMD;
672         }
673
674         ide_pktcmd_tf_load(drive, tf_flags, bcount);
675
676         /* Issue the packet command */
677         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
678                 if (drive->dma)
679                         drive->waiting_for_dma = 0;
680                 ide_execute_command(drive, ATA_CMD_PACKET, ide_transfer_pc,
681                                     timeout, expiry);
682                 return ide_started;
683         } else {
684                 ide_execute_pkt_cmd(drive);
685                 return ide_transfer_pc(drive);
686         }
687 }
688 EXPORT_SYMBOL_GPL(ide_issue_pc);