ide-atapi.c 18.2 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
/*
 * ATAPI support.
 */

#include <linux/kernel.h>
#include <linux/cdrom.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/gfp.h>

#include <scsi/scsi.h>

#define DRV_NAME "ide-atapi"
#define PFX DRV_NAME ": "

#ifdef DEBUG
#define debug_log(fmt, args...) \
	printk(KERN_INFO "ide: " fmt, ## args)
#else
#define debug_log(fmt, args...) do {} while (0)
#endif

#define ATAPI_MIN_CDB_BYTES	12

static inline int dev_is_idecd(ide_drive_t *drive)
{
	return drive->media == ide_cdrom || drive->media == ide_optical;
}

/*
 * Check whether we can support a device,
 * based on the ATAPI IDENTIFY command results.
 */
int ide_check_atapi_device(ide_drive_t *drive, const char *s)
{
	u16 *id = drive->id;
	u8 gcw[2], protocol, device_type, removable, drq_type, packet_size;

	*((u16 *)&gcw) = id[ATA_ID_CONFIG];

	protocol    = (gcw[1] & 0xC0) >> 6;
	device_type =  gcw[1] & 0x1F;
	removable   = (gcw[0] & 0x80) >> 7;
	drq_type    = (gcw[0] & 0x60) >> 5;
	packet_size =  gcw[0] & 0x03;

#ifdef CONFIG_PPC
	/* kludge for Apple PowerBook internal zip */
	if (drive->media == ide_floppy && device_type == 5 &&
	    !strstr((char *)&id[ATA_ID_PROD], "CD-ROM") &&
	    strstr((char *)&id[ATA_ID_PROD], "ZIP"))
		device_type = 0;
#endif

	if (protocol != 2)
		printk(KERN_ERR "%s: %s: protocol (0x%02x) is not ATAPI\n",
			s, drive->name, protocol);
	else if ((drive->media == ide_floppy && device_type != 0) ||
		 (drive->media == ide_tape && device_type != 1))
		printk(KERN_ERR "%s: %s: invalid device type (0x%02x)\n",
			s, drive->name, device_type);
	else if (removable == 0)
		printk(KERN_ERR "%s: %s: the removable flag is not set\n",
			s, drive->name);
	else if (drive->media == ide_floppy && drq_type == 3)
		printk(KERN_ERR "%s: %s: sorry, DRQ type (0x%02x) not "
			"supported\n", s, drive->name, drq_type);
	else if (packet_size != 0)
		printk(KERN_ERR "%s: %s: packet size (0x%02x) is not 12 "
			"bytes\n", s, drive->name, packet_size);
	else
		return 1;
	return 0;
}
EXPORT_SYMBOL_GPL(ide_check_atapi_device);

void ide_init_pc(struct ide_atapi_pc *pc)
{
	memset(pc, 0, sizeof(*pc));
}
EXPORT_SYMBOL_GPL(ide_init_pc);

/*
 * Add a special packet command request to the tail of the request queue,
 * and wait for it to be serviced.
 */
int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
		      struct ide_atapi_pc *pc, void *buf, unsigned int bufflen)
{
	struct request *rq;
	int error;

	rq = blk_get_request(drive->queue, REQ_OP_DRV_IN, __GFP_RECLAIM);
	ide_req(rq)->type = ATA_PRIV_MISC;
	rq->special = (char *)pc;

	if (buf && bufflen) {
		error = blk_rq_map_kern(drive->queue, rq, buf, bufflen,
					GFP_NOIO);
		if (error)
			goto put_req;
	}

	memcpy(scsi_req(rq)->cmd, pc->c, 12);
	if (drive->media == ide_tape)
		scsi_req(rq)->cmd[13] = REQ_IDETAPE_PC1;
	blk_execute_rq(drive->queue, disk, rq, 0);
	error = scsi_req(rq)->result ? -EIO : 0;
put_req:
	blk_put_request(rq);
	return error;
}
EXPORT_SYMBOL_GPL(ide_queue_pc_tail);

int ide_do_test_unit_ready(ide_drive_t *drive, struct gendisk *disk)
{
	struct ide_atapi_pc pc;

	ide_init_pc(&pc);
	pc.c[0] = TEST_UNIT_READY;

	return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
}
EXPORT_SYMBOL_GPL(ide_do_test_unit_ready);

int ide_do_start_stop(ide_drive_t *drive, struct gendisk *disk, int start)
{
	struct ide_atapi_pc pc;

	ide_init_pc(&pc);
	pc.c[0] = START_STOP;
	pc.c[4] = start;

	if (drive->media == ide_tape)
		pc.flags |= PC_FLAG_WAIT_FOR_DSC;

	return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
}
EXPORT_SYMBOL_GPL(ide_do_start_stop);

int ide_set_media_lock(ide_drive_t *drive, struct gendisk *disk, int on)
{
	struct ide_atapi_pc pc;

	if ((drive->dev_flags & IDE_DFLAG_DOORLOCKING) == 0)
		return 0;

	ide_init_pc(&pc);
	pc.c[0] = ALLOW_MEDIUM_REMOVAL;
	pc.c[4] = on;

	return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
}
EXPORT_SYMBOL_GPL(ide_set_media_lock);

void ide_create_request_sense_cmd(ide_drive_t *drive, struct ide_atapi_pc *pc)
{
	ide_init_pc(pc);
	pc->c[0] = REQUEST_SENSE;
	if (drive->media == ide_floppy) {
		pc->c[4] = 255;
		pc->req_xfer = 18;
	} else {
		pc->c[4] = 20;
		pc->req_xfer = 20;
	}
}
EXPORT_SYMBOL_GPL(ide_create_request_sense_cmd);

void ide_prep_sense(ide_drive_t *drive, struct request *rq)
{
	struct request_sense *sense = &drive->sense_data;
	struct request *sense_rq = drive->sense_rq;
	struct scsi_request *req = scsi_req(sense_rq);
	unsigned int cmd_len, sense_len;
	int err;

	switch (drive->media) {
	case ide_floppy:
		cmd_len = 255;
		sense_len = 18;
		break;
	case ide_tape:
		cmd_len = 20;
		sense_len = 20;
		break;
	default:
		cmd_len = 18;
		sense_len = 18;
	}

	BUG_ON(sense_len > sizeof(*sense));

	if (ata_sense_request(rq) || drive->sense_rq_armed)
		return;

	memset(sense, 0, sizeof(*sense));

	blk_rq_init(rq->q, sense_rq);
	scsi_req_init(req);

	err = blk_rq_map_kern(drive->queue, sense_rq, sense, sense_len,
			      GFP_NOIO);
	if (unlikely(err)) {
		if (printk_ratelimit())
			printk(KERN_WARNING PFX "%s: failed to map sense "
					    "buffer\n", drive->name);
		return;
	}

	sense_rq->rq_disk = rq->rq_disk;
	sense_rq->cmd_flags = REQ_OP_DRV_IN;
	ide_req(sense_rq)->type = ATA_PRIV_SENSE;
	sense_rq->rq_flags |= RQF_PREEMPT;

	req->cmd[0] = GPCMD_REQUEST_SENSE;
	req->cmd[4] = cmd_len;
	if (drive->media == ide_tape)
		req->cmd[13] = REQ_IDETAPE_PC1;

	drive->sense_rq_armed = true;
}
EXPORT_SYMBOL_GPL(ide_prep_sense);

int ide_queue_sense_rq(ide_drive_t *drive, void *special)
{
	/* deferred failure from ide_prep_sense() */
	if (!drive->sense_rq_armed) {
		printk(KERN_WARNING PFX "%s: error queuing a sense request\n",
		       drive->name);
		return -ENOMEM;
	}

	drive->sense_rq->special = special;
	drive->sense_rq_armed = false;

	drive->hwif->rq = NULL;

	elv_add_request(drive->queue, drive->sense_rq, ELEVATOR_INSERT_FRONT);
	return 0;
}
EXPORT_SYMBOL_GPL(ide_queue_sense_rq);

/*
 * Called when an error was detected during the last packet command.
 * We queue a request sense packet command at the head of the request
 * queue.
 */
void ide_retry_pc(ide_drive_t *drive)
{
	struct request *failed_rq = drive->hwif->rq;
	struct request *sense_rq = drive->sense_rq;
	struct ide_atapi_pc *pc = &drive->request_sense_pc;

	(void)ide_read_error(drive);

	/* init pc from sense_rq */
	ide_init_pc(pc);
	memcpy(pc->c, scsi_req(sense_rq)->cmd, 12);

	if (drive->media == ide_tape)
		drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;

	/*
	 * Push back the failed request and put request sense on top
	 * of it.  The failed command will be retried after sense data
	 * is acquired.
	 */
	drive->hwif->rq = NULL;
	ide_requeue_and_plug(drive, failed_rq);
	if (ide_queue_sense_rq(drive, pc)) {
		blk_start_request(failed_rq);
		ide_complete_rq(drive, BLK_STS_IOERR, blk_rq_bytes(failed_rq));
	}
}
EXPORT_SYMBOL_GPL(ide_retry_pc);

int ide_cd_expiry(ide_drive_t *drive)
{
	struct request *rq = drive->hwif->rq;
	unsigned long wait = 0;

	debug_log("%s: scsi_req(rq)->cmd[0]: 0x%x\n", __func__, scsi_req(rq)->cmd[0]);

	/*
	 * Some commands are *slow* and normally take a long time to complete.
	 * Usually we can use the ATAPI "disconnect" to bypass this, but not all
	 * commands/drives support that. Let ide_timer_expiry keep polling us
	 * for these.
	 */
	switch (scsi_req(rq)->cmd[0]) {
	case GPCMD_BLANK:
	case GPCMD_FORMAT_UNIT:
	case GPCMD_RESERVE_RZONE_TRACK:
	case GPCMD_CLOSE_TRACK:
	case GPCMD_FLUSH_CACHE:
		wait = ATAPI_WAIT_PC;
		break;
	default:
		if (!(rq->rq_flags & RQF_QUIET))
			printk(KERN_INFO PFX "cmd 0x%x timed out\n",
					 scsi_req(rq)->cmd[0]);
		wait = 0;
		break;
	}
	return wait;
}
EXPORT_SYMBOL_GPL(ide_cd_expiry);

int ide_cd_get_xferlen(struct request *rq)
{
	switch (req_op(rq)) {
	default:
		return 32768;
	case REQ_OP_SCSI_IN:
	case REQ_OP_SCSI_OUT:
		return blk_rq_bytes(rq);
	case REQ_OP_DRV_IN:
	case REQ_OP_DRV_OUT:
		switch (ide_req(rq)->type) {
		case ATA_PRIV_PC:
		case ATA_PRIV_SENSE:
			return blk_rq_bytes(rq);
		default:
			return 0;
		}
	}
}
EXPORT_SYMBOL_GPL(ide_cd_get_xferlen);

void ide_read_bcount_and_ireason(ide_drive_t *drive, u16 *bcount, u8 *ireason)
{
	struct ide_taskfile tf;

	drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_NSECT |
				     IDE_VALID_LBAM | IDE_VALID_LBAH);

	*bcount = (tf.lbah << 8) | tf.lbam;
	*ireason = tf.nsect & 3;
}
EXPORT_SYMBOL_GPL(ide_read_bcount_and_ireason);

/*
 * Check the contents of the interrupt reason register and attempt to recover if
 * there are problems.
 *
 * Returns:
 * - 0 if everything's ok
 * - 1 if the request has to be terminated.
 */
int ide_check_ireason(ide_drive_t *drive, struct request *rq, int len,
		      int ireason, int rw)
{
	ide_hwif_t *hwif = drive->hwif;

	debug_log("ireason: 0x%x, rw: 0x%x\n", ireason, rw);

	if (ireason == (!rw << 1))
		return 0;
	else if (ireason == (rw << 1)) {
		printk(KERN_ERR PFX "%s: %s: wrong transfer direction!\n",
				drive->name, __func__);

		if (dev_is_idecd(drive))
			ide_pad_transfer(drive, rw, len);
	} else if (!rw && ireason == ATAPI_COD) {
		if (dev_is_idecd(drive)) {
			/*
			 * Some drives (ASUS) seem to tell us that status info
			 * is available.  Just get it and ignore.
			 */
			(void)hwif->tp_ops->read_status(hwif);
			return 0;
		}
	} else {
		if (ireason & ATAPI_COD)
			printk(KERN_ERR PFX "%s: CoD != 0 in %s\n", drive->name,
					__func__);

		/* drive wants a command packet, or invalid ireason... */
		printk(KERN_ERR PFX "%s: %s: bad interrupt reason 0x%02x\n",
				drive->name, __func__, ireason);
	}

	if (dev_is_idecd(drive) && ata_pc_request(rq))
		rq->rq_flags |= RQF_FAILED;

	return 1;
}
EXPORT_SYMBOL_GPL(ide_check_ireason);

/*
 * This is the usual interrupt handler which will be called during a packet
 * command.  We will transfer some of the data (as requested by the drive)
 * and will re-point interrupt handler to us.
 */
static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
{
	struct ide_atapi_pc *pc = drive->pc;
	ide_hwif_t *hwif = drive->hwif;
	struct ide_cmd *cmd = &hwif->cmd;
	struct request *rq = hwif->rq;
	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
	unsigned int timeout, done;
	u16 bcount;
	u8 stat, ireason, dsc = 0;
	u8 write = !!(pc->flags & PC_FLAG_WRITING);

	debug_log("Enter %s - interrupt handler\n", __func__);

	timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
					       : WAIT_TAPE_CMD;

	/* Clear the interrupt */
	stat = tp_ops->read_status(hwif);

	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
		int rc;

		drive->waiting_for_dma = 0;
		rc = hwif->dma_ops->dma_end(drive);
		ide_dma_unmap_sg(drive, cmd);

		if (rc || (drive->media == ide_tape && (stat & ATA_ERR))) {
			if (drive->media == ide_floppy)
				printk(KERN_ERR PFX "%s: DMA %s error\n",
					drive->name, rq_data_dir(pc->rq)
						     ? "write" : "read");
			pc->flags |= PC_FLAG_DMA_ERROR;
		} else
			scsi_req(rq)->resid_len = 0;
		debug_log("%s: DMA finished\n", drive->name);
	}

	/* No more interrupts */
	if ((stat & ATA_DRQ) == 0) {
		int uptodate;
		blk_status_t error;

		debug_log("Packet command completed, %d bytes transferred\n",
			  blk_rq_bytes(rq));

		pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;

		local_irq_enable_in_hardirq();

		if (drive->media == ide_tape &&
		    (stat & ATA_ERR) && scsi_req(rq)->cmd[0] == REQUEST_SENSE)
			stat &= ~ATA_ERR;

		if ((stat & ATA_ERR) || (pc->flags & PC_FLAG_DMA_ERROR)) {
			/* Error detected */
			debug_log("%s: I/O error\n", drive->name);

			if (drive->media != ide_tape)
				scsi_req(pc->rq)->result++;

			if (scsi_req(rq)->cmd[0] == REQUEST_SENSE) {
				printk(KERN_ERR PFX "%s: I/O error in request "
						"sense command\n", drive->name);
				return ide_do_reset(drive);
			}

			debug_log("[cmd %x]: check condition\n", scsi_req(rq)->cmd[0]);

			/* Retry operation */
			ide_retry_pc(drive);

			/* queued, but not started */
			return ide_stopped;
		}
		pc->error = 0;

		if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)
			dsc = 1;

		/*
		 * ->pc_callback() might change rq->data_len for
		 * residual count, cache total length.
		 */
		done = blk_rq_bytes(rq);

		/* Command finished - Call the callback function */
		uptodate = drive->pc_callback(drive, dsc);

		if (uptodate == 0)
			drive->failed_pc = NULL;

		if (ata_misc_request(rq)) {
			scsi_req(rq)->result = 0;
			error = BLK_STS_OK;
		} else {

			if (blk_rq_is_passthrough(rq) && uptodate <= 0) {
				if (scsi_req(rq)->result == 0)
					scsi_req(rq)->result = -EIO;
			}

			error = uptodate ? BLK_STS_OK : BLK_STS_IOERR;
		}

		ide_complete_rq(drive, error, blk_rq_bytes(rq));
		return ide_stopped;
	}

	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
		pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
		printk(KERN_ERR PFX "%s: The device wants to issue more "
				"interrupts in DMA mode\n", drive->name);
		ide_dma_off(drive);
		return ide_do_reset(drive);
	}

	/* Get the number of bytes to transfer on this interrupt. */
	ide_read_bcount_and_ireason(drive, &bcount, &ireason);

	if (ide_check_ireason(drive, rq, bcount, ireason, write))
		return ide_do_reset(drive);

	done = min_t(unsigned int, bcount, cmd->nleft);
	ide_pio_bytes(drive, cmd, write, done);

	/* Update transferred byte count */
	scsi_req(rq)->resid_len -= done;

	bcount -= done;

	if (bcount)
		ide_pad_transfer(drive, write, bcount);

	debug_log("[cmd %x] transferred %d bytes, padded %d bytes, resid: %u\n",
		  scsi_req(rq)->cmd[0], done, bcount, scsi_req(rq)->resid_len);

	/* And set the interrupt handler again */
	ide_set_handler(drive, ide_pc_intr, timeout);
	return ide_started;
}

static void ide_init_packet_cmd(struct ide_cmd *cmd, u8 valid_tf,
				u16 bcount, u8 dma)
{
	cmd->protocol = dma ? ATAPI_PROT_DMA : ATAPI_PROT_PIO;
	cmd->valid.out.tf = IDE_VALID_LBAH | IDE_VALID_LBAM |
			    IDE_VALID_FEATURE | valid_tf;
	cmd->tf.command = ATA_CMD_PACKET;
	cmd->tf.feature = dma;		/* Use PIO/DMA */
	cmd->tf.lbam    = bcount & 0xff;
	cmd->tf.lbah    = (bcount >> 8) & 0xff;
}

static u8 ide_read_ireason(ide_drive_t *drive)
{
	struct ide_taskfile tf;

	drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_NSECT);

	return tf.nsect & 3;
}

static u8 ide_wait_ireason(ide_drive_t *drive, u8 ireason)
{
	int retries = 100;

	while (retries-- && ((ireason & ATAPI_COD) == 0 ||
		(ireason & ATAPI_IO))) {
		printk(KERN_ERR PFX "%s: (IO,CoD != (0,1) while issuing "
				"a packet command, retrying\n", drive->name);
		udelay(100);
		ireason = ide_read_ireason(drive);
		if (retries == 0) {
			printk(KERN_ERR PFX "%s: (IO,CoD != (0,1) while issuing"
					" a packet command, ignoring\n",
					drive->name);
			ireason |= ATAPI_COD;
			ireason &= ~ATAPI_IO;
		}
	}

	return ireason;
}

static int ide_delayed_transfer_pc(ide_drive_t *drive)
{
	/* Send the actual packet */
	drive->hwif->tp_ops->output_data(drive, NULL, drive->pc->c, 12);

	/* Timeout for the packet command */
	return WAIT_FLOPPY_CMD;
}

static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
{
	struct ide_atapi_pc *uninitialized_var(pc);
	ide_hwif_t *hwif = drive->hwif;
	struct request *rq = hwif->rq;
	ide_expiry_t *expiry;
	unsigned int timeout;
	int cmd_len;
	ide_startstop_t startstop;
	u8 ireason;

	if (ide_wait_stat(&startstop, drive, ATA_DRQ, ATA_BUSY, WAIT_READY)) {
		printk(KERN_ERR PFX "%s: Strange, packet command initiated yet "
				"DRQ isn't asserted\n", drive->name);
		return startstop;
	}

	if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
		if (drive->dma)
			drive->waiting_for_dma = 1;
	}

	if (dev_is_idecd(drive)) {
		/* ATAPI commands get padded out to 12 bytes minimum */
		cmd_len = COMMAND_SIZE(scsi_req(rq)->cmd[0]);
		if (cmd_len < ATAPI_MIN_CDB_BYTES)
			cmd_len = ATAPI_MIN_CDB_BYTES;

		timeout = rq->timeout;
		expiry  = ide_cd_expiry;
	} else {
		pc = drive->pc;

		cmd_len = ATAPI_MIN_CDB_BYTES;

		/*
		 * If necessary schedule the packet transfer to occur 'timeout'
		 * milliseconds later in ide_delayed_transfer_pc() after the
		 * device says it's ready for a packet.
		 */
		if (drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) {
			timeout = drive->pc_delay;
			expiry = &ide_delayed_transfer_pc;
		} else {
			timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
							       : WAIT_TAPE_CMD;
			expiry = NULL;
		}

		ireason = ide_read_ireason(drive);
		if (drive->media == ide_tape)
			ireason = ide_wait_ireason(drive, ireason);

		if ((ireason & ATAPI_COD) == 0 || (ireason & ATAPI_IO)) {
			printk(KERN_ERR PFX "%s: (IO,CoD) != (0,1) while "
				"issuing a packet command\n", drive->name);

			return ide_do_reset(drive);
		}
	}

	hwif->expiry = expiry;

	/* Set the interrupt routine */
	ide_set_handler(drive,
			(dev_is_idecd(drive) ? drive->irq_handler
					     : ide_pc_intr),
			timeout);

	/* Send the actual packet */
	if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
		hwif->tp_ops->output_data(drive, NULL, scsi_req(rq)->cmd, cmd_len);

	/* Begin DMA, if necessary */
	if (dev_is_idecd(drive)) {
		if (drive->dma)
			hwif->dma_ops->dma_start(drive);
	} else {
		if (pc->flags & PC_FLAG_DMA_OK) {
			pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
			hwif->dma_ops->dma_start(drive);
		}
	}

	return ide_started;
}

ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
{
	struct ide_atapi_pc *pc;
	ide_hwif_t *hwif = drive->hwif;
	ide_expiry_t *expiry = NULL;
	struct request *rq = hwif->rq;
	unsigned int timeout, bytes;
	u16 bcount;
	u8 valid_tf;
	u8 drq_int = !!(drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT);

	if (dev_is_idecd(drive)) {
		valid_tf = IDE_VALID_NSECT | IDE_VALID_LBAL;
		bcount = ide_cd_get_xferlen(rq);
		expiry = ide_cd_expiry;
		timeout = ATAPI_WAIT_PC;

		if (drive->dma)
			drive->dma = !ide_dma_prepare(drive, cmd);
	} else {
		pc = drive->pc;

		valid_tf = IDE_VALID_DEVICE;
		bytes = blk_rq_bytes(rq);
		bcount = ((drive->media == ide_tape) ? bytes
						     : min_t(unsigned int,
							     bytes, 63 * 1024));

		/* We haven't transferred any data yet */
		scsi_req(rq)->resid_len = bcount;

		if (pc->flags & PC_FLAG_DMA_ERROR) {
			pc->flags &= ~PC_FLAG_DMA_ERROR;
			ide_dma_off(drive);
		}

		if (pc->flags & PC_FLAG_DMA_OK)
			drive->dma = !ide_dma_prepare(drive, cmd);

		if (!drive->dma)
			pc->flags &= ~PC_FLAG_DMA_OK;

		timeout = (drive->media == ide_floppy) ? WAIT_FLOPPY_CMD
						       : WAIT_TAPE_CMD;
	}

	ide_init_packet_cmd(cmd, valid_tf, bcount, drive->dma);

	(void)do_rw_taskfile(drive, cmd);

	if (drq_int) {
		if (drive->dma)
			drive->waiting_for_dma = 0;
		hwif->expiry = expiry;
	}

	ide_execute_command(drive, cmd, ide_transfer_pc, timeout);

	return drq_int ? ide_started : ide_transfer_pc(drive);
}
EXPORT_SYMBOL_GPL(ide_issue_pc);