git.oblomov.eu Git - 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 #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         memcpy(rq->cmd, pc->c, 12);
 144         if (drive->media == ide_tape)
 145                 rq->cmd[13] = REQ_IDETAPE_PC1;
 146         ide_do_drive_cmd(drive, rq);
 147 }
 148
 149 /*
 150  * Add a special packet command request to the tail of the request queue,
 151  * and wait for it to be serviced.
 152  */
 153 int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
 154                       struct ide_atapi_pc *pc)
 155 {
 156         struct request *rq;
 157         int error;
 158
 159         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
 160         rq->cmd_type = REQ_TYPE_SPECIAL;
 161         rq->buffer = (char *)pc;
 162         memcpy(rq->cmd, pc->c, 12);
 163         if (drive->media == ide_tape)
 164                 rq->cmd[13] = REQ_IDETAPE_PC1;
 165         error = blk_execute_rq(drive->queue, disk, rq, 0);
 166         blk_put_request(rq);
 167
 168         return error;
 169 }
 170 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
 171
 172 int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
 173 {
 174         struct ide_atapi_pc pc;
 175
 176         ide_init_pc(&pc);
 177         pc.c[0] = TEST_UNIT_READY;
 178
 179         return ide_queue_pc_tail(drive, disk, &pc);
 180 }
 181 EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);
 182
 183 int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
 184 {
 185         struct ide_atapi_pc pc;
 186
 187         ide_init_pc(&pc);
 188         pc.c[0] = START_STOP;
 189         pc.c[4] = start;
 190
 191         if (drive->media == ide_tape)
 192                 pc.flags |= PC_FLAG_WAIT_FOR_DSC;
 193
 194         return ide_queue_pc_tail(drive, disk, &pc);
 195 }
 196 EXPORT_SYMBOL_GPL(ide_do_start_stop);
 197
 198 int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
 199 {
 200         struct ide_atapi_pc pc;
 201
 202         if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
 203                 return 0;
 204
 205         ide_init_pc(&pc);
 206         pc.c[0] = ALLOW_MEDIUM_REMOVAL;
 207         pc.c[4] = on;
 208
 209         return ide_queue_pc_tail(drive, disk, &pc);
 210 }
 211 EXPORT_SYMBOL_GPL(ide_set_media_lock);
 212
 213 void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
 214 {
 215         ide_init_pc(pc);
 216         pc->c[0] = REQUEST_SENSE;
 217         if (drive->media == ide_floppy) {
 218                 pc->c[4] = 255;
 219                 pc->req_xfer = 18;
 220         } else {
 221                 pc->c[4] = 20;
 222                 pc->req_xfer = 20;
 223         }
 224 }
 225 EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);
 226
 227 /*
 228  * Called when an error was detected during the last packet command.
 229  * We queue a request sense packet command in the head of the request list.
 230  */
 231 void ide_retry_pc(ide_drive_t *drive, struct gendisk *disk)
 232 {
 233         struct request *rq = &drive->request_sense_rq;
 234         struct ide_atapi_pc *pc = &drive->request_sense_pc;
 235
 236         (void)ide_read_error(drive);
 237         ide_create_request_sense_cmd(drive, pc);
 238         if (drive->media == ide_tape)
 239                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 240         ide_queue_pc_head(drive, disk, pc, rq);
 241 }
 242 EXPORT_SYMBOL_GPL(ide_retry_pc);
 243
 244 int ide_cd_expiry(ide_drive_t *drive)
 245 {
 246         struct request *rq = drive->hwif->rq;
 247         unsigned long wait = 0;
 248
 249         debug_log("%s: rq->cmd[0]: 0x%x\n", __func__, rq->cmd[0]);
 250
 251         /*
 252          * Some commands are *slow* and normally take a long time to complete.
 253          * Usually we can use the ATAPI "disconnect" to bypass this, but not all
 254          * commands/drives support that. Let ide_timer_expiry keep polling us
 255          * for these.
 256          */
 257         switch (rq->cmd[0]) {
 258         case GPCMD_BLANK:
 259         case GPCMD_FORMAT_UNIT:
 260         case GPCMD_RESERVE_RZONE_TRACK:
 261         case GPCMD_CLOSE_TRACK:
 262         case GPCMD_FLUSH_CACHE:
 263                 wait = ATAPI_WAIT_PC;
 264                 break;
 265         default:
 266                 if (!(rq->cmd_flags & REQ_QUIET))
 267                         printk(KERN_INFO "cmd 0x%x timed out\n",
 268                                          rq->cmd[0]);
 269                 wait = 0;
 270                 break;
 271         }
 272         return wait;
 273 }
 274 EXPORT_SYMBOL_GPL(ide_cd_expiry);
 275
 276 int ide_cd_get_xferlen(struct request *rq)
 277 {
 278         if (blk_fs_request(rq))
 279                 return 32768;
 280         else if (blk_sense_request(rq) || blk_pc_request(rq) ||
 281                          rq->cmd_type == REQ_TYPE_ATA_PC)
 282                 return rq->data_len;
 283         else
 284                 return 0;
 285 }
 286 EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);
 287
 288 /*
 289  * This is the usual interrupt handler which will be called during a packet
 290  * command.  We will transfer some of the data (as requested by the drive)
 291  * and will re-point interrupt handler to us.
 292  */
 293 static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 294 {
 295         struct ide_atapi_pc *pc = drive->pc;
 296         ide_hwif_t *hwif = drive->hwif;
 297         struct request *rq = hwif->rq;
 298         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
 299         xfer_func_t *xferfunc;
 300         unsigned int timeout, temp;
 301         u16 bcount;
 302         u8 stat, ireason, dsc = 0;
 303
 304         debug_log("Enter %s - interrupt handler\n", __func__);
 305
 306         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
 307                                                : WAIT_TAPE_CMD;
 308
 309         if (pc->flags & PC_FLAG_TIMEDOUT) {
 310                 drive->pc_callback(drive, 0);
 311                 return ide_stopped;
 312         }
 313
 314         /* Clear the interrupt */
 315         stat = tp_ops->read_status(hwif);
 316
 317         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 318                 if (hwif->dma_ops->dma_end(drive) ||
 319                     (drive->media == ide_tape && (stat & ATA_ERR))) {
 320                         if (drive->media == ide_floppy)
 321                                 printk(KERN_ERR "%s: DMA %s error\n",
 322                                         drive->name, rq_data_dir(pc->rq)
 323                                                      ? "write" : "read");
 324                         pc->flags |= PC_FLAG_DMA_ERROR;
 325                 } else {
 326                         pc->xferred = pc->req_xfer;
 327                         if (drive->pc_update_buffers)
 328                                 drive->pc_update_buffers(drive, pc);
 329                 }
 330                 debug_log("%s: DMA finished\n", drive->name);
 331         }
 332
 333         /* No more interrupts */
 334         if ((stat & ATA_DRQ) == 0) {
 335                 debug_log("Packet command completed, %d bytes transferred\n",
 336                           pc->xferred);
 337
 338                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 339
 340                 local_irq_enable_in_hardirq();
 341
 342                 if (drive->media == ide_tape &&
 343                     (stat & ATA_ERR) && rq->cmd[0] == REQUEST_SENSE)
 344                         stat &= ~ATA_ERR;
 345
 346                 if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
 347                         /* Error detected */
 348                         debug_log("%s: I/O error\n", drive->name);
 349
 350                         if (drive->media != ide_tape)
 351                                 pc->rq->errors++;
 352
 353                         if (rq->cmd[0] == REQUEST_SENSE) {
 354                                 printk(KERN_ERR "%s: I/O error in request sense"
 355                                                 " command\n", drive->name);
 356                                 return ide_do_reset(drive);
 357                         }
 358
 359                         debug_log("[cmd %x]: check condition\n", rq->cmd[0]);
 360
 361                         /* Retry operation */
 362                         ide_retry_pc(drive, rq->rq_disk);
 363
 364                         /* queued, but not started */
 365                         return ide_stopped;
 366                 }
 367                 pc->error = 0;
 368
 369                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
 370                         dsc = 1;
 371
 372                 /* Command finished - Call the callback function */
 373                 drive->pc_callback(drive, dsc);
 374
 375                 return ide_stopped;
 376         }
 377
 378         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 379                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 380                 printk(KERN_ERR "%s: The device wants to issue more interrupts "
 381                                 "in DMA mode\n", drive->name);
 382                 ide_dma_off(drive);
 383                 return ide_do_reset(drive);
 384         }
 385
 386         /* Get the number of bytes to transfer on this interrupt. */
 387         ide_read_bcount_and_ireason(drive, &bcount, &ireason);
 388
 389         if (ireason & ATAPI_COD) {
 390                 printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
 391                 return ide_do_reset(drive);
 392         }
 393
 394         if (((ireason & ATAPI_IO) == ATAPI_IO) ==
 395                 !!(pc->flags & PC_FLAG_WRITING)) {
 396                 /* Hopefully, we will never get here */
 397                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
 398                                 "to %s!\n", drive->name,
 399                                 (ireason & ATAPI_IO) ? "Write" : "Read",
 400                                 (ireason & ATAPI_IO) ? "Read" : "Write");
 401                 return ide_do_reset(drive);
 402         }
 403
 404         if (!(pc->flags & PC_FLAG_WRITING)) {
 405                 /* Reading - Check that we have enough space */
 406                 temp = pc->xferred + bcount;
 407                 if (temp > pc->req_xfer) {
 408                         if (temp > pc->buf_size) {
 409                                 printk(KERN_ERR "%s: The device wants to send "
 410                                                 "us more data than expected - "
 411                                                 "discarding data\n",
 412                                                 drive->name);
 413
 414                                 ide_pad_transfer(drive, 0, bcount);
 415                                 goto next_irq;
 416                         }
 417                         debug_log("The device wants to send us more data than "
 418                                   "expected - allowing transfer\n");
 419                 }
 420                 xferfunc = tp_ops->input_data;
 421         } else
 422                 xferfunc = tp_ops->output_data;
 423
 424         if ((drive->media == ide_floppy && !pc->buf) ||
 425             (drive->media == ide_tape && pc->bh)) {
 426                 int done = drive->pc_io_buffers(drive, pc, bcount,
 427                                   !!(pc->flags & PC_FLAG_WRITING));
 428
 429                 /* FIXME: don't do partial completions */
 430                 if (drive->media == ide_floppy)
 431                         ide_end_request(drive, 1, done >> 9);
 432         } else
 433                 xferfunc(drive, NULL, pc->cur_pos, bcount);
 434
 435         /* Update the current position */
 436         pc->xferred += bcount;
 437         pc->cur_pos += bcount;
 438
 439         debug_log("[cmd %x] transferred %d bytes on that intr.\n",
 440                   rq->cmd[0], bcount);
 441 next_irq:
 442         /* And set the interrupt handler again */
 443         ide_set_handler(drive, ide_pc_intr, timeout, NULL);
 444         return ide_started;
 445 }
 446
 447 static u8 ide_read_ireason(ide_drive_t *drive)
 448 {
 449         ide_task_t task;
 450
 451         memset(&task, 0, sizeof(task));
 452         task.tf_flags = IDE_TFLAG_IN_NSECT;
 453
 454         drive->hwif->tp_ops->tf_read(drive, &task);
 455
 456         return task.tf.nsect & 3;
 457 }
 458
 459 static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
 460 {
 461         int retries = 100;
 462
 463         while (retries-- && ((ireason & ATAPI_COD) == 0 ||
 464                 (ireason & ATAPI_IO))) {
 465                 printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
 466                                 "a packet command, retrying\n", drive->name);
 467                 udelay(100);
 468                 ireason = ide_read_ireason(drive);
 469                 if (retries == 0) {
 470                         printk(KERN_ERR "%s: (IO,CoD != (0,1) while issuing "
 471                                         "a packet command, ignoring\n",
 472                                         drive->name);
 473                         ireason |= ATAPI_COD;
 474                         ireason &= ~ATAPI_IO;
 475                 }
 476         }
 477
 478         return ireason;
 479 }
 480
 481 static int ide_delayed_transfer_pc(ide_drive_t *drive)
 482 {
 483         /* Send the actual packet */
 484         drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);
 485
 486         /* Timeout for the packet command */
 487         return WAIT_FLOPPY_CMD;
 488 }
 489
 490 static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
 491 {
 492         struct ide_atapi_pc *uninitialized_var(pc);
 493         ide_hwif_t *hwif = drive->hwif;
 494         struct request *rq = hwif->rq;
 495         ide_expiry_t *expiry;
 496         unsigned int timeout;
 497         int cmd_len;
 498         ide_startstop_t startstop;
 499         u8 ireason;
 500
 501         if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
 502                 printk(KERN_ERR "%s: Strange, packet command initiated yet "
 503                                 "DRQ isn't asserted\n", drive->name);
 504                 return startstop;
 505         }
 506
 507         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
 508                 if (drive->dma)
 509                         drive->waiting_for_dma = 1;
 510         }
 511
 512         if (dev_is_idecd(drive)) {
 513                 /* ATAPI commands get padded out to 12 bytes minimum */
 514                 cmd_len = COMMAND_SIZE(rq->cmd[0]);
 515                 if (cmd_len < ATAPI_MIN_CDB_BYTES)
 516                         cmd_len = ATAPI_MIN_CDB_BYTES;
 517
 518                 timeout = rq->timeout;
 519                 expiry  = ide_cd_expiry;
 520         } else {
 521                 pc = drive->pc;
 522
 523                 cmd_len = ATAPI_MIN_CDB_BYTES;
 524
 525                 /*
 526                  * If necessary schedule the packet transfer to occur 'timeout'
 527                  * miliseconds later in ide_delayed_transfer_pc() after the
 528                  * device says it's ready for a packet.
 529                  */
 530                 if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
 531                         timeout = drive->pc_delay;
 532                         expiry = &ide_delayed_transfer_pc;
 533                 } else {
 534                         timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
 535                                                                : WAIT_TAPE_CMD;
 536                         expiry = NULL;
 537                 }
 538
 539                 ireason = ide_read_ireason(drive);
 540                 if (drive->media == ide_tape)
 541                         ireason = ide_wait_ireason(drive, ireason);
 542
 543                 if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
 544                         printk(KERN_ERR "%s: (IO,CoD) != (0,1) while issuing "
 545                                         "a packet command\n", drive->name);
 546
 547                         return ide_do_reset(drive);
 548                 }
 549         }
 550
 551         /* Set the interrupt routine */
 552         ide_set_handler(drive,
 553                         (dev_is_idecd(drive) ? drive->irq_handler
 554                                              : ide_pc_intr),
 555                         timeout, expiry);
 556
 557         /* Begin DMA, if necessary */
 558         if (dev_is_idecd(drive)) {
 559                 if (drive->dma)
 560                         hwif->dma_ops->dma_start(drive);
 561         } else {
 562                 if (pc->flags & PC_FLAG_DMA_OK) {
 563                         pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
 564                         hwif->dma_ops->dma_start(drive);
 565                 }
 566         }
 567
 568         /* Send the actual packet */
 569         if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
 570                 hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
 571
 572         return ide_started;
 573 }
 574
 575 ide_startstop_t ide_issue_pc(ide_drive_t *drive)
 576 {
 577         struct ide_atapi_pc *pc;
 578         ide_hwif_t *hwif = drive->hwif;
 579         ide_expiry_t *expiry = NULL;
 580         unsigned int timeout;
 581         u32 tf_flags;
 582         u16 bcount;
 583
 584         if (dev_is_idecd(drive)) {
 585                 tf_flags = IDE_TFLAG_OUT_NSECT | IDE_TFLAG_OUT_LBAL;
 586                 bcount = ide_cd_get_xferlen(hwif->rq);
 587                 expiry = ide_cd_expiry;
 588                 timeout = ATAPI_WAIT_PC;
 589
 590                 if (drive->dma)
 591                         drive->dma = !hwif->dma_ops->dma_setup(drive);
 592         } else {
 593                 pc = drive->pc;
 594
 595                 /* We haven't transferred any data yet */
 596                 pc->xferred = 0;
 597                 pc->cur_pos = pc->buf;
 598
 599                 tf_flags = IDE_TFLAG_OUT_DEVICE;
 600                 bcount = ((drive->media == ide_tape) ?
 601                                 pc->req_xfer :
 602                                 min(pc->req_xfer, 63 * 1024));
 603
 604                 if (pc->flags & PC_FLAG_DMA_ERROR) {
 605                         pc->flags &= ~PC_FLAG_DMA_ERROR;
 606                         ide_dma_off(drive);
 607                 }
 608
 609                 if ((pc->flags & PC_FLAG_DMA_OK) &&
 610                      (drive->dev_flags & IDE_DFLAG_USING_DMA))
 611                         drive->dma = !hwif->dma_ops->dma_setup(drive);
 612
 613                 if (!drive->dma)
 614                         pc->flags &= ~PC_FLAG_DMA_OK;
 615
 616                 timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
 617                                                        : WAIT_TAPE_CMD;
 618         }
 619
 620         ide_pktcmd_tf_load(drive, tf_flags, bcount, drive->dma);
 621
 622         /* Issue the packet command */
 623         if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
 624                 if (drive->dma)
 625                         drive->waiting_for_dma = 0;
 626                 ide_execute_command(drive, ATA_CMD_PACKET, ide_transfer_pc,
 627                                     timeout, expiry);
 628                 return ide_started;
 629         } else {
 630                 ide_execute_pkt_cmd(drive);
 631                 return ide_transfer_pc(drive);
 632         }
 633 }
 634 EXPORT_SYMBOL_GPL(ide_issue_pc);