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