ide-floppy: do not map dataless cmds to an sg
[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         ide_do_drive_cmd(drive, rq);
153 }
154
155 /*
156  * Add a special packet command request to the tail of the request queue,
157  * and wait for it to be serviced.
158  */
159 int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
160                       struct ide_atapi_pc *pc)
161 {
162         struct request *rq;
163         int error;
164
165         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
166         rq->cmd_type = REQ_TYPE_SPECIAL;
167         rq->buffer = (char *)pc;
168
169         if (pc->req_xfer) {
170                 rq->data = pc->buf;
171                 rq->data_len = pc->req_xfer;
172         }
173
174         memcpy(rq->cmd, pc->c, 12);
175         if (drive->media == ide_tape)
176                 rq->cmd[13] = REQ_IDETAPE_PC1;
177         error = blk_execute_rq(drive->queue, disk, rq, 0);
178         blk_put_request(rq);
179
180         return error;
181 }
182 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
183
184 int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
185 {
186         struct ide_atapi_pc pc;
187
188         ide_init_pc(&pc);
189         pc.c[0] = TEST_UNIT_READY;
190
191         return ide_queue_pc_tail(drive, disk, &pc);
192 }
193 EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);
194
195 int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
196 {
197         struct ide_atapi_pc pc;
198
199         ide_init_pc(&pc);
200         pc.c[0] = START_STOP;
201         pc.c[4] = start;
202
203         if (drive->media == ide_tape)
204                 pc.flags |= PC_FLAG_WAIT_FOR_DSC;
205
206         return ide_queue_pc_tail(drive, disk, &pc);
207 }
208 EXPORT_SYMBOL_GPL(ide_do_start_stop);
209
210 int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
211 {
212         struct ide_atapi_pc pc;
213
214         if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
215                 return 0;
216
217         ide_init_pc(&pc);
218         pc.c[0] = ALLOW_MEDIUM_REMOVAL;
219         pc.c[4] = on;
220
221         return ide_queue_pc_tail(drive, disk, &pc);
222 }
223 EXPORT_SYMBOL_GPL(ide_set_media_lock);
224
225 void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
226 {
227         ide_init_pc(pc);
228         pc->c[0] = REQUEST_SENSE;
229         if (drive->media == ide_floppy) {
230                 pc->c[4] = 255;
231                 pc->req_xfer = 18;
232         } else {
233                 pc->c[4] = 20;
234                 pc->req_xfer = 20;
235         }
236 }
237 EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);
238
239 /*
240  * Called when an error was detected during the last packet command.
241  * We queue a request sense packet command in the head of the request list.
242  */
243 void ide_retry_pc(ide_drive_t *drive, struct gendisk *disk)
244 {
245         struct request *rq = &drive->request_sense_rq;
246         struct ide_atapi_pc *pc = &drive->request_sense_pc;
247
248         (void)ide_read_error(drive);
249         ide_create_request_sense_cmd(drive, pc);
250         if (drive->media == ide_tape)
251                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
252         ide_queue_pc_head(drive, disk, pc, rq);
253 }
254 EXPORT_SYMBOL_GPL(ide_retry_pc);
255
256 int ide_cd_expiry(ide_drive_t *drive)
257 {
258         struct request *rq = drive->hwif->rq;
259         unsigned long wait = 0;
260
261         debug_log("%s: rq->cmd[0]: 0x%x\n", __func__, rq->cmd[0]);
262
263         /*
264          * Some commands are *slow* and normally take a long time to complete.
265          * Usually we can use the ATAPI "disconnect" to bypass this, but not all
266          * commands/drives support that. Let ide_timer_expiry keep polling us
267          * for these.
268          */
269         switch (rq->cmd[0]) {
270         case GPCMD_BLANK:
271         case GPCMD_FORMAT_UNIT:
272         case GPCMD_RESERVE_RZONE_TRACK:
273         case GPCMD_CLOSE_TRACK:
274         case GPCMD_FLUSH_CACHE:
275                 wait = ATAPI_WAIT_PC;
276                 break;
277         default:
278                 if (!(rq->cmd_flags & REQ_QUIET))
279                         printk(KERN_INFO "cmd 0x%x timed out\n",
280                                          rq->cmd[0]);
281                 wait = 0;
282                 break;
283         }
284         return wait;
285 }
286 EXPORT_SYMBOL_GPL(ide_cd_expiry);
287
288 int ide_cd_get_xferlen(struct request *rq)
289 {
290         if (blk_fs_request(rq))
291                 return 32768;
292         else if (blk_sense_request(rq) || blk_pc_request(rq) ||
293                          rq->cmd_type == REQ_TYPE_ATA_PC)
294                 return rq->data_len;
295         else
296                 return 0;
297 }
298 EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
299
300 /*
301  * This is the usual interrupt handler which will be called during a packet
302  * command.  We will transfer some of the data (as requested by the drive)
303  * and will re-point interrupt handler to us.
304  */
305 static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
306 {
307         struct ide_atapi_pc *pc = drive->pc;
308         ide_hwif_t *hwif = drive->hwif;
309         struct request *rq = hwif->rq;
310         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
311         xfer_func_t *xferfunc;
312         unsigned int timeout, temp;
313         u16 bcount;
314         u8 stat, ireason, dsc = 0;
315
316         debug_log("Enter %s - interrupt handler\n", __func__);
317
318         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
319                                                : WAIT_TAPE_CMD;
320
321         if (pc->flags & PC_FLAG_TIMEDOUT) {
322                 drive->pc_callback(drive, 0);
323                 return ide_stopped;
324         }
325
326         /* Clear the interrupt */
327         stat = tp_ops->read_status(hwif);
328
329         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
330                 if (hwif->dma_ops->dma_end(drive) ||
331                     (drive->media == ide_tape && (stat & ATA_ERR))) {
332                         if (drive->media == ide_floppy)
333                                 printk(KERN_ERR "%s: DMA %s error\n",
334                                         drive->name, rq_data_dir(pc->rq)
335                                                      ? "write" : "read");
336                         pc->flags |= PC_FLAG_DMA_ERROR;
337                 } else {
338                         pc->xferred = pc->req_xfer;
339                         if (drive->pc_update_buffers)
340                                 drive->pc_update_buffers(drive, pc);
341                 }
342                 debug_log("%s: DMA finished\n", drive->name);
343         }
344
345         /* No more interrupts */
346         if ((stat & ATA_DRQ) == 0) {
347                 debug_log("Packet command completed, %d bytes transferred\n",
348                           pc->xferred);
349
350                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
351
352                 local_irq_enable_in_hardirq();
353
354                 if (drive->media == ide_tape &&
355                     (stat & ATA_ERR) && rq->cmd[0] == REQUEST_SENSE)
356                         stat &= ~ATA_ERR;
357
358                 if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
359                         /* Error detected */
360                         debug_log("%s: I/O error\n", drive->name);
361
362                         if (drive->media != ide_tape)
363                                 pc->rq->errors++;
364
365                         if (rq->cmd[0] == REQUEST_SENSE) {
366                                 printk(KERN_ERR "%s: I/O error in request sense"
367                                                 " command\n", drive->name);
368                                 return ide_do_reset(drive);
369                         }
370
371                         debug_log("[cmd %x]: check condition\n", rq->cmd[0]);
372
373                         /* Retry operation */
374                         ide_retry_pc(drive, rq->rq_disk);
375
376                         /* queued, but not started */
377                         return ide_stopped;
378                 }
379                 pc->error = 0;
380
381                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
382                         dsc = 1;
383
384                 /* Command finished - Call the callback function */
385                 drive->pc_callback(drive, dsc);
386
387                 return ide_stopped;
388         }
389
390         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
391                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
392                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
393                                 "in DMA mode\n", drive->name);
394                 ide_dma_off(drive);
395                 return ide_do_reset(drive);
396         }
397
398         /* Get the number of bytes to transfer on this interrupt. */
399         ide_read_bcount_and_ireason(drive, &bcount, &ireason);
400
401         if (ireason & ATAPI_COD) {
402                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
403                 return ide_do_reset(drive);
404         }
405
406         if (((ireason & ATAPI_IO) == ATAPI_IO) ==
407                 !!(pc->flags & PC_FLAG_WRITING)) {
408                 /* Hopefully, we will never get here */
409                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
410                                 "to %s!\n", drive->name,
411                                 (ireason & ATAPI_IO) ? "Write" : "Read",
412                                 (ireason & ATAPI_IO) ? "Read" : "Write");
413                 return ide_do_reset(drive);
414         }
415
416         if (!(pc->flags & PC_FLAG_WRITING)) {
417                 /* Reading - Check that we have enough space */
418                 temp = pc->xferred + bcount;
419                 if (temp > pc->req_xfer) {
420                         if (temp > pc->buf_size) {
421                                 printk(KERN_ERR "%s: The device wants to send "
422                                                 "us more data than expected - "
423                                                 "discarding data\n",
424                                                 drive->name);
425
426                                 ide_pad_transfer(drive, 0, bcount);
427                                 goto next_irq;
428                         }
429                         debug_log("The device wants to send us more data than "
430                                   "expected - allowing transfer\n");
431                 }
432                 xferfunc = tp_ops->input_data;
433         } else
434                 xferfunc = tp_ops->output_data;
435
436         if ((drive->media == ide_floppy && !pc->buf) ||
437             (drive->media == ide_tape && pc->bh)) {
438                 int done = drive->pc_io_buffers(drive, pc, bcount,
439                                   !!(pc->flags & PC_FLAG_WRITING));
440
441                 /* FIXME: don't do partial completions */
442                 if (drive->media == ide_floppy)
443                         ide_end_request(drive, 1, done >> 9);
444         } else
445                 xferfunc(drive, NULL, pc->cur_pos, bcount);
446
447         /* Update the current position */
448         pc->xferred += bcount;
449         pc->cur_pos += bcount;
450
451         debug_log("[cmd %x] transferred %d bytes on that intr.\n",
452                   rq->cmd[0], bcount);
453 next_irq:
454         /* And set the interrupt handler again */
455         ide_set_handler(drive, ide_pc_intr, timeout, NULL);
456         return ide_started;
457 }
458
459 static u8 ide_read_ireason(ide_drive_t *drive)
460 {
461         ide_task_t task;
462
463         memset(&task, 0, sizeof(task));
464         task.tf_flags = IDE_TFLAG_IN_NSECT;
465
466         drive->hwif->tp_ops->tf_read(drive, &task);
467
468         return task.tf.nsect & 3;
469 }
470
471 static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
472 {
473         int retries = 100;
474
475         while (retries-- && ((ireason & ATAPI_COD) == 0 ||
476                 (ireason & ATAPI_IO))) {
477                 printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
478                                 "a packet command, retrying\n", drive->name);
479                 udelay(100);
480                 ireason = ide_read_ireason(drive);
481                 if (retries == 0) {
482                         printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
483                                         "a packet command, ignoring\n",
484                                         drive->name);
485                         ireason |= ATAPI_COD;
486                         ireason &= ~ATAPI_IO;
487                 }
488         }
489
490         return ireason;
491 }
492
493 static int ide_delayed_transfer_pc(ide_drive_t *drive)
494 {
495         /* Send the actual packet */
496         drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);
497
498         /* Timeout for the packet command */
499         return WAIT_FLOPPY_CMD;
500 }
501
502 static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
503 {
504         struct ide_atapi_pc *uninitialized_var(pc);
505         ide_hwif_t *hwif = drive->hwif;
506         struct request *rq = hwif->rq;
507         ide_expiry_t *expiry;
508         unsigned int timeout;
509         int cmd_len;
510         ide_startstop_t startstop;
511         u8 ireason;
512
513         if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
514                 printk(KERN_ERR "%s: Strange, packet command initiated yet "
515                                 "DRQ isn't asserted\n", drive->name);
516                 return startstop;
517         }
518
519         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
520                 if (drive->dma)
521                         drive->waiting_for_dma = 1;
522         }
523
524         if (dev_is_idecd(drive)) {
525                 /* ATAPI commands get padded out to 12 bytes minimum */
526                 cmd_len = COMMAND_SIZE(rq->cmd[0]);
527                 if (cmd_len < ATAPI_MIN_CDB_BYTES)
528                         cmd_len = ATAPI_MIN_CDB_BYTES;
529
530                 timeout = rq->timeout;
531                 expiry  = ide_cd_expiry;
532         } else {
533                 pc = drive->pc;
534
535                 cmd_len = ATAPI_MIN_CDB_BYTES;
536
537                 /*
538                  * If necessary schedule the packet transfer to occur 'timeout'
539                  * miliseconds later in ide_delayed_transfer_pc() after the
540                  * device says it's ready for a packet.
541                  */
542                 if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
543                         timeout = drive->pc_delay;
544                         expiry = &ide_delayed_transfer_pc;
545                 } else {
546                         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
547                                                                : WAIT_TAPE_CMD;
548                         expiry = NULL;
549                 }
550
551                 ireason = ide_read_ireason(drive);
552                 if (drive->media == ide_tape)
553                         ireason = ide_wait_ireason(drive, ireason);
554
555                 if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
556                         printk(KERN_ERR "%s: (IO,CoD) != (0,1) while issuing "
557                                         "a packet command\n", drive->name);
558
559                         return ide_do_reset(drive);
560                 }
561         }
562
563         /* Set the interrupt routine */
564         ide_set_handler(drive,
565                         (dev_is_idecd(drive) ? drive->irq_handler
566                                              : ide_pc_intr),
567                         timeout, expiry);
568
569         /* Begin DMA, if necessary */
570         if (dev_is_idecd(drive)) {
571                 if (drive->dma)
572                         hwif->dma_ops->dma_start(drive);
573         } else {
574                 if (pc->flags & PC_FLAG_DMA_OK) {
575                         pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
576                         hwif->dma_ops->dma_start(drive);
577                 }
578         }
579
580         /* Send the actual packet */
581         if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
582                 hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
583
584         return ide_started;
585 }
586
587 ide_startstop_t ide_issue_pc(ide_drive_t *drive)
588 {
589         struct ide_atapi_pc *pc;
590         ide_hwif_t *hwif = drive->hwif;
591         ide_expiry_t *expiry = NULL;
592         unsigned int timeout;
593         u32 tf_flags;
594         u16 bcount;
595
596         if (dev_is_idecd(drive)) {
597                 tf_flags = IDE_TFLAG_OUT_NSECT | IDE_TFLAG_OUT_LBAL;
598                 bcount = ide_cd_get_xferlen(hwif->rq);
599                 expiry = ide_cd_expiry;
600                 timeout = ATAPI_WAIT_PC;
601
602                 if (drive->dma)
603                         drive->dma = !hwif->dma_ops->dma_setup(drive);
604         } else {
605                 pc = drive->pc;
606
607                 /* We haven't transferred any data yet */
608                 pc->xferred = 0;
609                 pc->cur_pos = pc->buf;
610
611                 tf_flags = IDE_TFLAG_OUT_DEVICE;
612                 bcount = ((drive->media == ide_tape) ?
613                                 pc->req_xfer :
614                                 min(pc->req_xfer, 63 * 1024));
615
616                 if (pc->flags & PC_FLAG_DMA_ERROR) {
617                         pc->flags &= ~PC_FLAG_DMA_ERROR;
618                         ide_dma_off(drive);
619                 }
620
621                 if ((pc->flags & PC_FLAG_DMA_OK) &&
622                      (drive->dev_flags & IDE_DFLAG_USING_DMA))
623                         drive->dma = !hwif->dma_ops->dma_setup(drive);
624
625                 if (!drive->dma)
626                         pc->flags &= ~PC_FLAG_DMA_OK;
627
628                 timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
629                                                        : WAIT_TAPE_CMD;
630         }
631
632         ide_pktcmd_tf_load(drive, tf_flags, bcount, drive->dma);
633
634         /* Issue the packet command */
635         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
636                 if (drive->dma)
637                         drive->waiting_for_dma = 0;
638                 ide_execute_command(drive, ATA_CMD_PACKET, ide_transfer_pc,
639                                     timeout, expiry);
640                 return ide_started;
641         } else {
642                 ide_execute_pkt_cmd(drive);
643                 return ide_transfer_pc(drive);
644         }
645 }
646 EXPORT_SYMBOL_GPL(ide_issue_pc);