drivers/ide/ide-atapi.c - linux - Git at Google

 /*
  * ATAPI support.
  */

 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/ide.h>
 #include <scsi/scsi.h>

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

 /*
  * 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);

 /* PIO data transfer routine using the scatter gather table. */
 int ide_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 		    unsigned int bcount, int write)
 {
 	ide_hwif_t *hwif = drive->hwif;
 	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
 	xfer_func_t *xf = write ? tp_ops->output_data : tp_ops->input_data;
 	struct scatterlist *sg = pc->sg;
 	char *buf;
 	int count, done = 0;

 	while (bcount) {
 		count = min(sg->length - pc->b_count, bcount);

 		if (PageHighMem(sg_page(sg))) {
 			unsigned long flags;

 			local_irq_save(flags);
 			buf = kmap_atomic(sg_page(sg), KM_IRQ0) + sg->offset;
 			xf(drive, NULL, buf + pc->b_count, count);
 			kunmap_atomic(buf - sg->offset, KM_IRQ0);
 			local_irq_restore(flags);
 		} else {
 			buf = sg_virt(sg);
 			xf(drive, NULL, buf + pc->b_count, count);
 		}

 		bcount -= count;
 		pc->b_count += count;
 		done += count;

 		if (pc->b_count == sg->length) {
 			if (!--pc->sg_cnt)
 				break;
 			pc->sg = sg = sg_next(sg);
 			pc->b_count = 0;
 		}
 	}

 	if (bcount) {
 		printk(KERN_ERR "%s: %d leftover bytes, %s\n", drive->name,
 			bcount, write ? "padding with zeros"
 				      : "discarding data");
 		ide_pad_transfer(drive, write, bcount);
 	}

 	return done;
 }
 EXPORT_SYMBOL_GPL(ide_io_buffers);

 void ide_init_pc(struct ide_atapi_pc *pc)
 {
 	memset(pc, 0, sizeof(*pc));
 	pc->buf = pc->pc_buf;
 	pc->buf_size = IDE_PC_BUFFER_SIZE;
 }
 EXPORT_SYMBOL_GPL(ide_init_pc);

 /*
  * Generate a new packet command request in front of the request queue, before
  * the current request, so that it will be processed immediately, on the next
  * pass through the driver.
  */
 void ide_queue_pc_head(ide_drive_t *drive, struct gendisk *disk,
 		       struct ide_atapi_pc *pc, struct request *rq)
 {
 	blk_rq_init(NULL, rq);
 	rq->cmd_type = REQ_TYPE_SPECIAL;
 	rq->cmd_flags |= REQ_PREEMPT;
 	rq->buffer = (char *)pc;
 	rq->rq_disk = disk;
 	memcpy(rq->cmd, pc->c, 12);
 	if (drive->media == ide_tape)
 		rq->cmd[13] = REQ_IDETAPE_PC1;
 	ide_do_drive_cmd(drive, rq);
 }
 EXPORT_SYMBOL_GPL(ide_queue_pc_head);

 /*
  * 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)
 {
 	struct request *rq;
 	int error;

 	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
 	rq->cmd_type = REQ_TYPE_SPECIAL;
 	rq->buffer = (char *)pc;
 	memcpy(rq->cmd, pc->c, 12);
 	if (drive->media == ide_tape)
 		rq->cmd[13] = REQ_IDETAPE_PC1;
 	error = blk_execute_rq(drive->queue, disk, rq, 0);
 	blk_put_request(rq);

 	return error;
 }
 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);

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

 	if (drive->atapi_flags & IDE_AFLAG_NO_DOORLOCK)
 		return 0;

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

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

 /* TODO: unify the code thus making some arguments go away */
 ide_startstop_t ide_pc_intr(ide_drive_t *drive, struct ide_atapi_pc *pc,
 	ide_handler_t *handler, unsigned int timeout, ide_expiry_t *expiry,
 	void (*update_buffers)(ide_drive_t *, struct ide_atapi_pc *),
 	void (*retry_pc)(ide_drive_t *), void (*dsc_handle)(ide_drive_t *),
 	int (*io_buffers)(ide_drive_t *, struct ide_atapi_pc *, unsigned, int))
 {
 	ide_hwif_t *hwif = drive->hwif;
 	struct request *rq = hwif->hwgroup->rq;
 	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
 	xfer_func_t *xferfunc;
 	unsigned int temp;
 	u16 bcount;
 	u8 stat, ireason, scsi = drive->scsi;

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

 	if (pc->flags & PC_FLAG_TIMEDOUT) {
 		drive->pc_callback(drive);
 		return ide_stopped;
 	}

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

 	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 		if (hwif->dma_ops->dma_end(drive) ||
 		    (drive->media == ide_tape && !scsi && (stat & ATA_ERR))) {
 			if (drive->media == ide_floppy && !scsi)
 				printk(KERN_ERR "%s: DMA %s error\n",
 					drive->name, rq_data_dir(pc->rq)
 						     ? "write" : "read");
 			pc->flags |= PC_FLAG_DMA_ERROR;
 		} else {
 			pc->xferred = pc->req_xfer;
 			if (update_buffers)
 				update_buffers(drive, pc);
 		}
 		debug_log("%s: DMA finished\n", drive->name);
 	}

 	/* No more interrupts */
 	if ((stat & ATA_DRQ) == 0) {
 		debug_log("Packet command completed, %d bytes transferred\n",
 			  pc->xferred);

 		pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;

 		local_irq_enable_in_hardirq();

 		if (drive->media == ide_tape && !scsi &&
 		    (stat & ATA_ERR) && 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) {
 				pc->rq->errors++;
 				if (scsi)
 					goto cmd_finished;
 			}

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

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

 			/* Retry operation */
 			retry_pc(drive);

 			/* queued, but not started */
 			return ide_stopped;
 		}
 cmd_finished:
 		pc->error = 0;
 		if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
 		    (stat & ATA_DSC) == 0) {
 			dsc_handle(drive);
 			return ide_stopped;
 		}

 		/* Command finished - Call the callback function */
 		drive->pc_callback(drive);

 		return ide_stopped;
 	}

 	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 		pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 		printk(KERN_ERR "%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 (ireason & ATAPI_COD) {
 		printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
 		return ide_do_reset(drive);
 	}

 	if (((ireason & ATAPI_IO) == ATAPI_IO) ==
 		!!(pc->flags & PC_FLAG_WRITING)) {
 		/* Hopefully, we will never get here */
 		printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
 				"to %s!\n", drive->name,
 				(ireason & ATAPI_IO) ? "Write" : "Read",
 				(ireason & ATAPI_IO) ? "Read" : "Write");
 		return ide_do_reset(drive);
 	}

 	if (!(pc->flags & PC_FLAG_WRITING)) {
 		/* Reading - Check that we have enough space */
 		temp = pc->xferred + bcount;
 		if (temp > pc->req_xfer) {
 			if (temp > pc->buf_size) {
 				printk(KERN_ERR "%s: The device wants to send "
 						"us more data than expected - "
 						"discarding data\n",
 						drive->name);
 				if (scsi)
 					temp = pc->buf_size - pc->xferred;
 				else
 					temp = 0;
 				if (temp) {
 					if (pc->sg)
 						io_buffers(drive, pc, temp, 0);
 					else
 						tp_ops->input_data(drive, NULL,
 							pc->cur_pos, temp);
 					printk(KERN_ERR "%s: transferred %d of "
 							"%d bytes\n",
 							drive->name,
 							temp, bcount);
 				}
 				pc->xferred += temp;
 				pc->cur_pos += temp;
 				ide_pad_transfer(drive, 0, bcount - temp);
 				ide_set_handler(drive, handler, timeout,
 						expiry);
 				return ide_started;
 			}
 			debug_log("The device wants to send us more data than "
 				  "expected - allowing transfer\n");
 		}
 		xferfunc = tp_ops->input_data;
 	} else
 		xferfunc = tp_ops->output_data;

 	if ((drive->media == ide_floppy && !scsi && !pc->buf) ||
 	    (drive->media == ide_tape && !scsi && pc->bh) ||
 	    (scsi && pc->sg)) {
 		int done = io_buffers(drive, pc, bcount,
 				  !!(pc->flags & PC_FLAG_WRITING));

 		/* FIXME: don't do partial completions */
 		if (drive->media == ide_floppy && !scsi)
 			ide_end_request(drive, 1, done >> 9);
 	} else
 		xferfunc(drive, NULL, pc->cur_pos, bcount);

 	/* Update the current position */
 	pc->xferred += bcount;
 	pc->cur_pos += bcount;

 	debug_log("[cmd %x] transferred %d bytes on that intr.\n",
 		  rq->cmd[0], bcount);

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

 static u8 ide_read_ireason(ide_drive_t *drive)
 {
 	ide_task_t task;

 	memset(&task, 0, sizeof(task));
 	task.tf_flags = IDE_TFLAG_IN_NSECT;

 	drive->hwif->tp_ops->tf_read(drive, &task);

 	return task.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 "%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 "%s: (IO,CoD != (0,1) while issuing "
 					"a packet command, ignoring\n",
 					drive->name);
 			ireason |= ATAPI_COD;
 			ireason &= ~ATAPI_IO;
 		}
 	}

 	return ireason;
 }

 ide_startstop_t ide_transfer_pc(ide_drive_t *drive, struct ide_atapi_pc *pc,
 				ide_handler_t *handler, unsigned int timeout,
 				ide_expiry_t *expiry)
 {
 	ide_hwif_t *hwif = drive->hwif;
 	struct request *rq = hwif->hwgroup->rq;
 	ide_startstop_t startstop;
 	u8 ireason;

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

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

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

 	/* Set the interrupt routine */
 	ide_set_handler(drive, handler, timeout, expiry);

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

 	/* Send the actual packet */
 	if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
 		hwif->tp_ops->output_data(drive, NULL, rq->cmd, 12);

 	return ide_started;
 }
 EXPORT_SYMBOL_GPL(ide_transfer_pc);

 ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_atapi_pc *pc,
 			     ide_handler_t *handler, unsigned int timeout,
 			     ide_expiry_t *expiry)
 {
 	ide_hwif_t *hwif = drive->hwif;
 	u16 bcount;
 	u8 dma = 0;

 	/* We haven't transferred any data yet */
 	pc->xferred = 0;
 	pc->cur_pos = pc->buf;

 	/* Request to transfer the entire buffer at once */
 	if (drive->media == ide_tape && !drive->scsi)
 		bcount = pc->req_xfer;
 	else
 		bcount = min(pc->req_xfer, 63 * 1024);

 	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->using_dma) {
 		if (drive->scsi)
 			hwif->sg_mapped = 1;
 		dma = !hwif->dma_ops->dma_setup(drive);
 		if (drive->scsi)
 			hwif->sg_mapped = 0;
 	}

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

 	ide_pktcmd_tf_load(drive, drive->scsi ? 0 : IDE_TFLAG_OUT_DEVICE,
 			   bcount, dma);

 	/* Issue the packet command */
 	if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
 		ide_execute_command(drive, ATA_CMD_PACKET, handler,
 				    timeout, NULL);
 		return ide_started;
 	} else {
 		ide_execute_pkt_cmd(drive);
 		return (*handler)(drive);
 	}
 }
 EXPORT_SYMBOL_GPL(ide_issue_pc);
	/*
	* ATAPI support.
	*/

	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/ide.h>
	#include <scsi/scsi.h>

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

	/*
	* 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);

	/* PIO data transfer routine using the scatter gather table. */
	int ide_io_buffers(ide_drive_t drive, struct ide_atapi_pc pc,
	unsigned int bcount, int write)
	{
	ide_hwif_t *hwif = drive->hwif;
	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
	xfer_func_t *xf = write ? tp_ops->output_data : tp_ops->input_data;
	struct scatterlist *sg = pc->sg;
	char *buf;
	int count, done = 0;

	while (bcount) {
	count = min(sg->length - pc->b_count, bcount);

	if (PageHighMem(sg_page(sg))) {
	unsigned long flags;

	local_irq_save(flags);
	buf = kmap_atomic(sg_page(sg), KM_IRQ0) + sg->offset;
	xf(drive, NULL, buf + pc->b_count, count);
	kunmap_atomic(buf - sg->offset, KM_IRQ0);
	local_irq_restore(flags);
	} else {
	buf = sg_virt(sg);
	xf(drive, NULL, buf + pc->b_count, count);
	}

	bcount -= count;
	pc->b_count += count;
	done += count;

	if (pc->b_count == sg->length) {
	if (!--pc->sg_cnt)
	break;
	pc->sg = sg = sg_next(sg);
	pc->b_count = 0;
	}
	}

	if (bcount) {
	printk(KERN_ERR "%s: %d leftover bytes, %s\n", drive->name,
	bcount, write ? "padding with zeros"
	: "discarding data");
	ide_pad_transfer(drive, write, bcount);
	}

	return done;
	}
	EXPORT_SYMBOL_GPL(ide_io_buffers);

	void ide_init_pc(struct ide_atapi_pc *pc)
	{
	memset(pc, 0, sizeof(*pc));
	pc->buf = pc->pc_buf;
	pc->buf_size = IDE_PC_BUFFER_SIZE;
	}
	EXPORT_SYMBOL_GPL(ide_init_pc);

	/*
	* Generate a new packet command request in front of the request queue, before
	* the current request, so that it will be processed immediately, on the next
	* pass through the driver.
	*/
	void ide_queue_pc_head(ide_drive_t drive, struct gendisk disk,
	struct ide_atapi_pc pc, struct request rq)
	{
	blk_rq_init(NULL, rq);
	rq->cmd_type = REQ_TYPE_SPECIAL;
	rq->cmd_flags \|= REQ_PREEMPT;
	rq->buffer = (char *)pc;
	rq->rq_disk = disk;
	memcpy(rq->cmd, pc->c, 12);
	if (drive->media == ide_tape)
	rq->cmd[13] = REQ_IDETAPE_PC1;
	ide_do_drive_cmd(drive, rq);
	}
	EXPORT_SYMBOL_GPL(ide_queue_pc_head);

	/*
	* 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)
	{
	struct request *rq;
	int error;

	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
	rq->cmd_type = REQ_TYPE_SPECIAL;
	rq->buffer = (char *)pc;
	memcpy(rq->cmd, pc->c, 12);
	if (drive->media == ide_tape)
	rq->cmd[13] = REQ_IDETAPE_PC1;
	error = blk_execute_rq(drive->queue, disk, rq, 0);
	blk_put_request(rq);

	return error;
	}
	EXPORT_SYMBOL_GPL(ide_queue_pc_tail);

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

	if (drive->atapi_flags & IDE_AFLAG_NO_DOORLOCK)
	return 0;

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

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

	/* TODO: unify the code thus making some arguments go away */
	ide_startstop_t ide_pc_intr(ide_drive_t drive, struct ide_atapi_pc pc,
	ide_handler_t handler, unsigned int timeout, ide_expiry_t expiry,
	void (update_buffers)(ide_drive_t , struct ide_atapi_pc *),
	void (retry_pc)(ide_drive_t ), void (dsc_handle)(ide_drive_t ),
	int (io_buffers)(ide_drive_t , struct ide_atapi_pc *, unsigned, int))
	{
	ide_hwif_t *hwif = drive->hwif;
	struct request *rq = hwif->hwgroup->rq;
	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
	xfer_func_t *xferfunc;
	unsigned int temp;
	u16 bcount;
	u8 stat, ireason, scsi = drive->scsi;

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

	if (pc->flags & PC_FLAG_TIMEDOUT) {
	drive->pc_callback(drive);
	return ide_stopped;
	}

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

	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
	if (hwif->dma_ops->dma_end(drive) \|\|
	(drive->media == ide_tape && !scsi && (stat & ATA_ERR))) {
	if (drive->media == ide_floppy && !scsi)
	printk(KERN_ERR "%s: DMA %s error\n",
	drive->name, rq_data_dir(pc->rq)
	? "write" : "read");
	pc->flags \|= PC_FLAG_DMA_ERROR;
	} else {
	pc->xferred = pc->req_xfer;
	if (update_buffers)
	update_buffers(drive, pc);
	}
	debug_log("%s: DMA finished\n", drive->name);
	}

	/* No more interrupts */
	if ((stat & ATA_DRQ) == 0) {
	debug_log("Packet command completed, %d bytes transferred\n",
	pc->xferred);

	pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;

	local_irq_enable_in_hardirq();

	if (drive->media == ide_tape && !scsi &&
	(stat & ATA_ERR) && 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) {
	pc->rq->errors++;
	if (scsi)
	goto cmd_finished;
	}

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

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

	/* Retry operation */
	retry_pc(drive);

	/* queued, but not started */
	return ide_stopped;
	}
	cmd_finished:
	pc->error = 0;
	if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
	(stat & ATA_DSC) == 0) {
	dsc_handle(drive);
	return ide_stopped;
	}

	/* Command finished - Call the callback function */
	drive->pc_callback(drive);

	return ide_stopped;
	}

	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
	pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
	printk(KERN_ERR "%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 (ireason & ATAPI_COD) {
	printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
	return ide_do_reset(drive);
	}

	if (((ireason & ATAPI_IO) == ATAPI_IO) ==
	!!(pc->flags & PC_FLAG_WRITING)) {
	/* Hopefully, we will never get here */
	printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
	"to %s!\n", drive->name,
	(ireason & ATAPI_IO) ? "Write" : "Read",
	(ireason & ATAPI_IO) ? "Read" : "Write");
	return ide_do_reset(drive);
	}

	if (!(pc->flags & PC_FLAG_WRITING)) {
	/* Reading - Check that we have enough space */
	temp = pc->xferred + bcount;
	if (temp > pc->req_xfer) {
	if (temp > pc->buf_size) {
	printk(KERN_ERR "%s: The device wants to send "
	"us more data than expected - "
	"discarding data\n",
	drive->name);
	if (scsi)
	temp = pc->buf_size - pc->xferred;
	else
	temp = 0;
	if (temp) {
	if (pc->sg)
	io_buffers(drive, pc, temp, 0);
	else
	tp_ops->input_data(drive, NULL,
	pc->cur_pos, temp);
	printk(KERN_ERR "%s: transferred %d of "
	"%d bytes\n",
	drive->name,
	temp, bcount);
	}
	pc->xferred += temp;
	pc->cur_pos += temp;
	ide_pad_transfer(drive, 0, bcount - temp);
	ide_set_handler(drive, handler, timeout,
	expiry);
	return ide_started;
	}
	debug_log("The device wants to send us more data than "
	"expected - allowing transfer\n");
	}
	xferfunc = tp_ops->input_data;
	} else
	xferfunc = tp_ops->output_data;

	if ((drive->media == ide_floppy && !scsi && !pc->buf) \|\|
	(drive->media == ide_tape && !scsi && pc->bh) \|\|
	(scsi && pc->sg)) {
	int done = io_buffers(drive, pc, bcount,
	!!(pc->flags & PC_FLAG_WRITING));

	/* FIXME: don't do partial completions */
	if (drive->media == ide_floppy && !scsi)
	ide_end_request(drive, 1, done >> 9);
	} else
	xferfunc(drive, NULL, pc->cur_pos, bcount);

	/* Update the current position */
	pc->xferred += bcount;
	pc->cur_pos += bcount;

	debug_log("[cmd %x] transferred %d bytes on that intr.\n",
	rq->cmd[0], bcount);

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

	static u8 ide_read_ireason(ide_drive_t *drive)
	{
	ide_task_t task;

	memset(&task, 0, sizeof(task));
	task.tf_flags = IDE_TFLAG_IN_NSECT;

	drive->hwif->tp_ops->tf_read(drive, &task);

	return task.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 "%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 "%s: (IO,CoD != (0,1) while issuing "
	"a packet command, ignoring\n",
	drive->name);
	ireason \|= ATAPI_COD;
	ireason &= ~ATAPI_IO;
	}
	}

	return ireason;
	}

	ide_startstop_t ide_transfer_pc(ide_drive_t drive, struct ide_atapi_pc pc,
	ide_handler_t *handler, unsigned int timeout,
	ide_expiry_t *expiry)
	{
	ide_hwif_t *hwif = drive->hwif;
	struct request *rq = hwif->hwgroup->rq;
	ide_startstop_t startstop;
	u8 ireason;

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

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

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

	/* Set the interrupt routine */
	ide_set_handler(drive, handler, timeout, expiry);

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

	/* Send the actual packet */
	if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
	hwif->tp_ops->output_data(drive, NULL, rq->cmd, 12);

	return ide_started;
	}
	EXPORT_SYMBOL_GPL(ide_transfer_pc);

	ide_startstop_t ide_issue_pc(ide_drive_t drive, struct ide_atapi_pc pc,
	ide_handler_t *handler, unsigned int timeout,
	ide_expiry_t *expiry)
	{
	ide_hwif_t *hwif = drive->hwif;
	u16 bcount;
	u8 dma = 0;

	/* We haven't transferred any data yet */
	pc->xferred = 0;
	pc->cur_pos = pc->buf;

	/* Request to transfer the entire buffer at once */
	if (drive->media == ide_tape && !drive->scsi)
	bcount = pc->req_xfer;
	else
	bcount = min(pc->req_xfer, 63 * 1024);

	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->using_dma) {
	if (drive->scsi)
	hwif->sg_mapped = 1;
	dma = !hwif->dma_ops->dma_setup(drive);
	if (drive->scsi)
	hwif->sg_mapped = 0;
	}

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

	ide_pktcmd_tf_load(drive, drive->scsi ? 0 : IDE_TFLAG_OUT_DEVICE,
	bcount, dma);

	/* Issue the packet command */
	if (drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT) {
	ide_execute_command(drive, ATA_CMD_PACKET, handler,
	timeout, NULL);
	return ide_started;
	} else {
	ide_execute_pkt_cmd(drive);
	return (*handler)(drive);
	}
	}
	EXPORT_SYMBOL_GPL(ide_issue_pc);