1 files changed, 739 insertions, 0 deletions

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
new file mode 100644
index 000000000..4224c4dd8
--- /dev/null
+++ b/drivers/ide/ide-atapi.c
@@ -0,0 +1,739 @@
+/*
+ * 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, 0);
+	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;
+
+	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);