SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 static inline int dev_is_idecd(ide_drive_t *drive)
  19 {
  20         return drive->media == ide_cdrom || drive->media == ide_optical;
  21 }
  22
  23 /*
  24  * Check whether we can support a device,
  25  * based on the ATAPI IDENTIFY command results.
  26  */
  27 int ide_check_atapi_device(ide_drive_t *drive, const char *s)
  28 {
  29         u16 *id = drive->id;
  30         u8 gcw[2], protocol, device_type, removable, drq_type, packet_size;
  31
  32         *((u16 *)&gcw) = id[ATA_ID_CONFIG];
  33
  34         protocol    = (gcw[1] & 0xC0) >> 6;
  35         device_type =  gcw[1] & 0x1F;
  36         removable   = (gcw[0] & 0x80) >> 7;
  37         drq_type    = (gcw[0] & 0x60) >> 5;
  38         packet_size =  gcw[0] & 0x03;
  39
  40 #ifdef CONFIG_PPC
  41         /* kludge for Apple PowerBook internal zip */
  42         if (drive->media == ide_floppy && device_type == 5 &&
  43             !strstr((char *)&id[ATA_ID_PROD], "CD-ROM") &&
  44             strstr((char *)&id[ATA_ID_PROD], "ZIP"))
  45                 device_type = 0;
  46 #endif
  47
  48         if (protocol != 2)
  49                 printk(KERN_ERR "%s: %s: protocol (0x%02x) is not ATAPI\n",
  50                         s, drive->name, protocol);
  51         else if ((drive->media == ide_floppy && device_type != 0) ||
  52                  (drive->media == ide_tape && device_type != 1))
  53                 printk(KERN_ERR "%s: %s: invalid device type (0x%02x)\n",
  54                         s, drive->name, device_type);
  55         else if (removable == 0)
  56                 printk(KERN_ERR "%s: %s: the removable flag is not set\n",
  57                         s, drive->name);
  58         else if (drive->media == ide_floppy && drq_type == 3)
  59                 printk(KERN_ERR "%s: %s: sorry, DRQ type (0x%02x) not "
  60                         "supported\n", s, drive->name, drq_type);
  61         else if (packet_size != 0)
  62                 printk(KERN_ERR "%s: %s: packet size (0x%02x) is not 12 "
  63                         "bytes\n", s, drive->name, packet_size);
  64         else
  65                 return 1;
  66         return 0;
  67 }
  68 EXPORT_SYMBOL_GPL(ide_check_atapi_device);
  69
  70 /* PIO data transfer routine using the scatter gather table. */
  71 int ide_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
  72                     unsigned int bcount, int write)
  73 {
  74         ide_hwif_t *hwif = drive->hwif;
  75         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
  76         xfer_func_t *xf = write ? tp_ops->output_data : tp_ops->input_data;
  77         struct scatterlist *sg = pc->sg;
  78         char *buf;
  79         int count, done = 0;
  80
  81         while (bcount) {
  82                 count = min(sg->length - pc->b_count, bcount);
  83
  84                 if (PageHighMem(sg_page(sg))) {
  85                         unsigned long flags;
  86
  87                         local_irq_save(flags);
  88                         buf = kmap_atomic(sg_page(sg), KM_IRQ0) + sg->offset;
  89                         xf(drive, NULL, buf + pc->b_count, count);
  90                         kunmap_atomic(buf - sg->offset, KM_IRQ0);
  91                         local_irq_restore(flags);
  92                 } else {
  93                         buf = sg_virt(sg);
  94                         xf(drive, NULL, buf + pc->b_count, count);
  95                 }
  96
  97                 bcount -= count;
  98                 pc->b_count += count;
  99                 done += count;
 100
 101                 if (pc->b_count == sg->length) {
 102                         if (!--pc->sg_cnt)
 103                                 break;
 104                         pc->sg = sg = sg_next(sg);
 105                         pc->b_count = 0;
 106                 }
 107         }
 108
 109         if (bcount) {
 110                 printk(KERN_ERR "%s: %d leftover bytes, %s\n", drive->name,
 111                         bcount, write ? "padding with zeros"
 112                                       : "discarding data");
 113                 ide_pad_transfer(drive, write, bcount);
 114         }
 115
 116         return done;
 117 }
 118 EXPORT_SYMBOL_GPL(ide_io_buffers);
 119
 120 void ide_init_pc(struct ide_atapi_pc *pc)
 121 {
 122         memset(pc, 0, sizeof(*pc));
 123         pc->buf = pc->pc_buf;
 124         pc->buf_size = IDE_PC_BUFFER_SIZE;
 125 }
 126 EXPORT_SYMBOL_GPL(ide_init_pc);
 127
 128 /*
 129  * Generate a new packet command request in front of the request queue, before
 130  * the current request, so that it will be processed immediately, on the next
 131  * pass through the driver.
 132  */
 133 static void ide_queue_pc_head(ide_drive_t *drive, struct gendisk *disk,
 134                               struct ide_atapi_pc *pc, struct request *rq)
 135 {
 136         blk_rq_init(NULL, rq);
 137         rq->cmd_type = REQ_TYPE_SPECIAL;
 138         rq->cmd_flags |= REQ_PREEMPT;
 139         rq->buffer = (char *)pc;
 140         rq->rq_disk = disk;
 141         memcpy(rq->cmd, pc->c, 12);
 142         if (drive->media == ide_tape)
 143                 rq->cmd[13] = REQ_IDETAPE_PC1;
 144         ide_do_drive_cmd(drive, rq);
 145 }
 146
 147 /*
 148  * Add a special packet command request to the tail of the request queue,
 149  * and wait for it to be serviced.
 150  */
 151 int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
 152                       struct ide_atapi_pc *pc)
 153 {
 154         struct request *rq;
 155         int error;
 156
 157         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
 158         rq->cmd_type = REQ_TYPE_SPECIAL;
 159         rq->buffer = (char *)pc;
 160         memcpy(rq->cmd, pc->c, 12);
 161         if (drive->media == ide_tape)
 162                 rq->cmd[13] = REQ_IDETAPE_PC1;
 163         error = blk_execute_rq(drive->queue, disk, rq, 0);
 164         blk_put_request(rq);
 165
 166         return error;
 167 }
 168 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
 169
 170 int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
 171 {
 172         struct ide_atapi_pc pc;
 173
 174         ide_init_pc(&pc);
 175         pc.c[0] = TEST_UNIT_READY;
 176
 177         return ide_queue_pc_tail(drive, disk, &pc);
 178 }
 179 EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);
 180
 181 int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
 182 {
 183         struct ide_atapi_pc pc;
 184
 185         ide_init_pc(&pc);
 186         pc.c[0] = START_STOP;
 187         pc.c[4] = start;
 188
 189         if (drive->media == ide_tape)
 190                 pc.flags |= PC_FLAG_WAIT_FOR_DSC;
 191
 192         return ide_queue_pc_tail(drive, disk, &pc);
 193 }
 194 EXPORT_SYMBOL_GPL(ide_do_start_stop);
 195
 196 int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
 197 {
 198         struct ide_atapi_pc pc;
 199
 200         if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
 201                 return 0;
 202
 203         ide_init_pc(&pc);
 204         pc.c[0] = ALLOW_MEDIUM_REMOVAL;
 205         pc.c[4] = on;
 206
 207         return ide_queue_pc_tail(drive, disk, &pc);
 208 }
 209 EXPORT_SYMBOL_GPL(ide_set_media_lock);
 210
 211 void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
 212 {
 213         ide_init_pc(pc);
 214         pc->c[0] = REQUEST_SENSE;
 215         if (drive->media == ide_floppy) {
 216                 pc->c[4] = 255;
 217                 pc->req_xfer = 18;
 218         } else {
 219                 pc->c[4] = 20;
 220                 pc->req_xfer = 20;
 221         }
 222 }
 223 EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);
 224
 225 /*
 226  * Called when an error was detected during the last packet command.
 227  * We queue a request sense packet command in the head of the request list.
 228  */
 229 void ide_retry_pc(ide_drive_t *drive, struct gendisk *disk)
 230 {
 231         struct request *rq = &drive->request_sense_rq;
 232         struct ide_atapi_pc *pc = &drive->request_sense_pc;
 233
 234         (void)ide_read_error(drive);
 235         ide_create_request_sense_cmd(drive, pc);
 236         if (drive->media == ide_tape)
 237                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 238         ide_queue_pc_head(drive, disk, pc, rq);
 239 }
 240 EXPORT_SYMBOL_GPL(ide_retry_pc);
 241
 242 int ide_cd_expiry(ide_drive_t *drive)
 243 {
 244         struct request *rq = HWGROUP(drive)->rq;
 245         unsigned long wait = 0;
 246
 247         debug_log("%s: rq->cmd[0]: 0x%x\n", __func__, rq->cmd[0]);
 248
 249         /*
 250          * Some commands are *slow* and normally take a long time to complete.
 251          * Usually we can use the ATAPI "disconnect" to bypass this, but not all
 252          * commands/drives support that. Let ide_timer_expiry keep polling us
 253          * for these.
 254          */
 255         switch (rq->cmd[0]) {
 256         case GPCMD_BLANK:
 257         case GPCMD_FORMAT_UNIT:
 258         case GPCMD_RESERVE_RZONE_TRACK:
 259         case GPCMD_CLOSE_TRACK:
 260         case GPCMD_FLUSH_CACHE:
 261                 wait = ATAPI_WAIT_PC;
 262                 break;
 263         default:
 264                 if (!(rq->cmd_flags & REQ_QUIET))
 265                         printk(KERN_INFO "cmd 0x%x timed out\n",
 266                                          rq->cmd[0]);
 267                 wait = 0;
 268                 break;
 269         }
 270         return wait;
 271 }
 272 EXPORT_SYMBOL_GPL(ide_cd_expiry);
 273
 274 int ide_cd_get_xferlen(struct request *rq)
 275 {
 276         if (blk_fs_request(rq))
 277                 return 32768;
 278         else if (blk_sense_request(rq) || blk_pc_request(rq) ||
 279                          rq->cmd_type == REQ_TYPE_ATA_PC)
 280                 return rq->data_len;
 281         else
 282                 return 0;
 283 }
 284 EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
 285
 286 /*
 287  * This is the usual interrupt handler which will be called during a packet
 288  * command.  We will transfer some of the data (as requested by the drive)
 289  * and will re-point interrupt handler to us.
 290  */
 291 static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 292 {
 293         struct ide_atapi_pc *pc = drive->pc;
 294         ide_hwif_t *hwif = drive->hwif;
 295         struct request *rq = hwif->hwgroup->rq;
 296         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
 297         xfer_func_t *xferfunc;
 298         unsigned int timeout, temp;
 299         u16 bcount;
 300         u8 stat, ireason, dsc = 0;
 301
 302         debug_log("Enter %s - interrupt handler\n", __func__);
 303
 304         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
 305                                                : WAIT_TAPE_CMD;
 306
 307         if (pc->flags & PC_FLAG_TIMEDOUT) {
 308                 drive->pc_callback(drive, 0);
 309                 return ide_stopped;
 310         }
 311
 312         /* Clear the interrupt */
 313         stat = tp_ops->read_status(hwif);
 314
 315         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 316                 if (hwif->dma_ops->dma_end(drive) ||
 317                     (drive->media == ide_tape && (stat & ATA_ERR))) {
 318                         if (drive->media == ide_floppy)
 319                                 printk(KERN_ERR "%s: DMA %s error\n",
 320                                         drive->name, rq_data_dir(pc->rq)
 321                                                      ? "write" : "read");
 322                         pc->flags |= PC_FLAG_DMA_ERROR;
 323                 } else {
 324                         pc->xferred = pc->req_xfer;
 325                         if (drive->pc_update_buffers)
 326                                 drive->pc_update_buffers(drive, pc);
 327                 }
 328                 debug_log("%s: DMA finished\n", drive->name);
 329         }
 330
 331         /* No more interrupts */
 332         if ((stat & ATA_DRQ) == 0) {
 333                 debug_log("Packet command completed, %d bytes transferred\n",
 334                           pc->xferred);
 335
 336                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 337
 338                 local_irq_enable_in_hardirq();
 339
 340                 if (drive->media == ide_tape &&
 341                     (stat & ATA_ERR) && rq->cmd[0] == REQUEST_SENSE)
 342                         stat &= ~ATA_ERR;
 343
 344                 if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
 345                         /* Error detected */
 346                         debug_log("%s: I/O error\n", drive->name);
 347
 348                         if (drive->media != ide_tape)
 349                                 pc->rq->errors++;
 350
 351                         if (rq->cmd[0] == REQUEST_SENSE) {
 352                                 printk(KERN_ERR "%s: I/O error in request sense"
 353                                                 " command\n", drive->name);
 354                                 return ide_do_reset(drive);
 355                         }
 356
 357                         debug_log("[cmd %x]: check condition\n", rq->cmd[0]);
 358
 359                         /* Retry operation */
 360                         ide_retry_pc(drive, rq->rq_disk);
 361
 362                         /* queued, but not started */
 363                         return ide_stopped;
 364                 }
 365                 pc->error = 0;
 366
 367                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
 368                         dsc = 1;
 369
 370                 /* Command finished - Call the callback function */
 371                 drive->pc_callback(drive, dsc);
 372
 373                 return ide_stopped;
 374         }
 375
 376         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 377                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 378                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
 379                                 "in DMA mode\n", drive->name);
 380                 ide_dma_off(drive);
 381                 return ide_do_reset(drive);
 382         }
 383
 384         /* Get the number of bytes to transfer on this interrupt. */
 385         ide_read_bcount_and_ireason(drive, &bcount, &ireason);
 386
 387         if (ireason & ATAPI_COD) {
 388                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
 389                 return ide_do_reset(drive);
 390         }
 391
 392         if (((ireason & ATAPI_IO) == ATAPI_IO) ==
 393                 !!(pc->flags & PC_FLAG_WRITING)) {
 394                 /* Hopefully, we will never get here */
 395                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
 396                                 "to %s!\n", drive->name,
 397                                 (ireason & ATAPI_IO) ? "Write" : "Read",
 398                                 (ireason & ATAPI_IO) ? "Read" : "Write");
 399                 return ide_do_reset(drive);
 400         }
 401
 402         if (!(pc->flags & PC_FLAG_WRITING)) {
 403                 /* Reading - Check that we have enough space */
 404                 temp = pc->xferred + bcount;
 405                 if (temp > pc->req_xfer) {
 406                         if (temp > pc->buf_size) {
 407                                 printk(KERN_ERR "%s: The device wants to send "
 408                                                 "us more data than expected - "
 409                                                 "discarding data\n",
 410                                                 drive->name);
 411
 412                                 ide_pad_transfer(drive, 0, bcount);
 413                                 goto next_irq;
 414                         }
 415                         debug_log("The device wants to send us more data than "
 416                                   "expected - allowing transfer\n");
 417                 }
 418                 xferfunc = tp_ops->input_data;
 419         } else
 420                 xferfunc = tp_ops->output_data;
 421
 422         if ((drive->media == ide_floppy && !pc->buf) ||
 423             (drive->media == ide_tape && pc->bh)) {
 424                 int done = drive->pc_io_buffers(drive, pc, bcount,
 425                                   !!(pc->flags & PC_FLAG_WRITING));
 426
 427                 /* FIXME: don't do partial completions */
 428                 if (drive->media == ide_floppy)
 429                         ide_end_request(drive, 1, done >> 9);
 430         } else
 431                 xferfunc(drive, NULL, pc->cur_pos, bcount);
 432
 433         /* Update the current position */
 434         pc->xferred += bcount;
 435         pc->cur_pos += bcount;
 436
 437         debug_log("[cmd %x] transferred %d bytes on that intr.\n",
 438                   rq->cmd[0], bcount);
 439 next_irq:
 440         /* And set the interrupt handler again */
 441         ide_set_handler(drive, ide_pc_intr, timeout, NULL);
 442         return ide_started;
 443 }
 444
 445 static u8 ide_read_ireason(ide_drive_t *drive)
 446 {
 447         ide_task_t task;
 448
 449         memset(&task, 0, sizeof(task));
 450         task.tf_flags = IDE_TFLAG_IN_NSECT;
 451
 452         drive->hwif->tp_ops->tf_read(drive, &task);
 453
 454         return task.tf.nsect & 3;
 455 }
 456
 457 static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
 458 {
 459         int retries = 100;
 460
 461         while (retries-- && ((ireason & ATAPI_COD) == 0 ||
 462                 (ireason & ATAPI_IO))) {
 463                 printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
 464                                 "a packet command, retrying\n", drive->name);
 465                 udelay(100);
 466                 ireason = ide_read_ireason(drive);
 467                 if (retries == 0) {
 468                         printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
 469                                         "a packet command, ignoring\n",
 470                                         drive->name);
 471                         ireason |= ATAPI_COD;
 472                         ireason &= ~ATAPI_IO;
 473                 }
 474         }
 475
 476         return ireason;
 477 }
 478
 479 static int ide_delayed_transfer_pc(ide_drive_t *drive)
 480 {
 481         /* Send the actual packet */
 482         drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);
 483
 484         /* Timeout for the packet command */
 485         return WAIT_FLOPPY_CMD;
 486 }
 487
 488 static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
 489 {
 490         struct ide_atapi_pc *pc = drive->pc;
 491         ide_hwif_t *hwif = drive->hwif;
 492         struct request *rq = hwif->hwgroup->rq;
 493         ide_expiry_t *expiry;
 494         unsigned int timeout;
 495         ide_startstop_t startstop;
 496         u8 ireason;
 497
 498         if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
 499                 printk(KERN_ERR "%s: Strange, packet command initiated yet "
 500                                 "DRQ isn't asserted\n", drive->name);
 501                 return startstop;
 502         }
 503
 504         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
 505                 if (drive->dma)
 506                         drive->waiting_for_dma = 1;
 507         }
 508
 509         ireason = ide_read_ireason(drive);
 510         if (drive->media == ide_tape)
 511                 ireason = ide_wait_ireason(drive, ireason);
 512
 513         if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
 514                 printk(KERN_ERR "%s: (IO,CoD) != (0,1) while issuing "
 515                                 "a packet command\n", drive->name);
 516                 return ide_do_reset(drive);
 517         }
 518
 519         /*
 520          * If necessary schedule the packet transfer to occur 'timeout'
 521          * miliseconds later in ide_delayed_transfer_pc() after the device
 522          * says it's ready for a packet.
 523          */
 524         if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
 525                 timeout = drive->pc_delay;
 526                 expiry = &ide_delayed_transfer_pc;
 527         } else {
 528                 timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
 529                                                        : WAIT_TAPE_CMD;
 530                 expiry = NULL;
 531         }
 532
 533         /* Set the interrupt routine */
 534         ide_set_handler(drive, ide_pc_intr, timeout, expiry);
 535
 536         /* Begin DMA, if necessary */
 537         if (pc->flags & PC_FLAG_DMA_OK) {
 538                 pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
 539                 hwif->dma_ops->dma_start(drive);
 540         }
 541
 542         /* Send the actual packet */
 543         if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
 544                 hwif->tp_ops->output_data(drive, NULL, rq->cmd, 12);
 545
 546         return ide_started;
 547 }
 548
 549 ide_startstop_t ide_issue_pc(ide_drive_t *drive, unsigned int timeout)
 550 {
 551         struct ide_atapi_pc *pc = drive->pc;
 552         ide_hwif_t *hwif = drive->hwif;
 553         ide_expiry_t *expiry = NULL;
 554         u32 tf_flags;
 555         u16 bcount;
 556
 557         /* We haven't transferred any data yet */
 558         pc->xferred = 0;
 559         pc->cur_pos = pc->buf;
 560
 561         if (dev_is_idecd(drive)) {
 562                 tf_flags = IDE_TFLAG_OUT_NSECT | IDE_TFLAG_OUT_LBAL;
 563                 bcount = ide_cd_get_xferlen(hwif->hwgroup->rq);
 564                 expiry = ide_cd_expiry;
 565         } else {
 566                 tf_flags = IDE_TFLAG_OUT_DEVICE;
 567                 bcount = ((drive->media == ide_tape) ?
 568                                 pc->req_xfer :
 569                                 min(pc->req_xfer, 63 * 1024));
 570         }
 571
 572         if (pc->flags & PC_FLAG_DMA_ERROR) {
 573                 pc->flags &= ~PC_FLAG_DMA_ERROR;
 574                 ide_dma_off(drive);
 575         }
 576
 577         if (((pc->flags & PC_FLAG_DMA_OK) &&
 578                 (drive->dev_flags & IDE_DFLAG_USING_DMA)) ||
 579             drive->dma)
 580                 drive->dma = !hwif->dma_ops->dma_setup(drive);
 581
 582         if (!drive->dma)
 583                 pc->flags &= ~PC_FLAG_DMA_OK;
 584
 585         ide_pktcmd_tf_load(drive, tf_flags, bcount, drive->dma);
 586
 587         /* Issue the packet command */
 588         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
 589                 if (drive->dma)
 590                         drive->waiting_for_dma = 0;
 591                 ide_execute_command(drive, ATA_CMD_PACKET, ide_transfer_pc,
 592                                     timeout, expiry);
 593                 return ide_started;
 594         } else {
 595                 ide_execute_pkt_cmd(drive);
 596                 return ide_transfer_pc(drive);
 597         }
 598 }
 599 EXPORT_SYMBOL_GPL(ide_issue_pc);