Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 1539 insertions, 0 deletions

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
new file mode 100644
index 0000000..81f99bd
--- /dev/null
+++ b/drivers/ide/ide-io.c
@@ -0,0 +1,1539 @@
+/*
+ *	IDE I/O functions
+ *
+ *	Basic PIO and command management functionality.
+ *
+ * This code was split off from ide.c. See ide.c for history and original
+ * copyrights.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * For the avoidance of doubt the "preferred form" of this code is one which
+ * is in an open non patent encumbered format. Where cryptographic key signing
+ * forms part of the process of creating an executable the information
+ * including keys needed to generate an equivalently functional executable
+ * are deemed to be part of the source code.
+ */
+ 
+ 
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/major.h>
+#include <linux/errno.h>
+#include <linux/genhd.h>
+#include <linux/blkpg.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/ide.h>
+#include <linux/hdreg.h>
+#include <linux/completion.h>
+#include <linux/reboot.h>
+#include <linux/cdrom.h>
+#include <linux/seq_file.h>
+#include <linux/device.h>
+#include <linux/kmod.h>
+#include <linux/scatterlist.h>
+#include <linux/bitops.h>
+
+#include <asm/byteorder.h>
+#include <asm/irq.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+static int __ide_end_request(ide_drive_t *drive, struct request *rq,
+			     int uptodate, unsigned int nr_bytes, int dequeue)
+{
+	int ret = 1;
+	int error = 0;
+
+	if (uptodate <= 0)
+		error = uptodate ? uptodate : -EIO;
+
+	/*
+	 * if failfast is set on a request, override number of sectors and
+	 * complete the whole request right now
+	 */
+	if (blk_noretry_request(rq) && error)
+		nr_bytes = rq->hard_nr_sectors << 9;
+
+	if (!blk_fs_request(rq) && error && !rq->errors)
+		rq->errors = -EIO;
+
+	/*
+	 * decide whether to reenable DMA -- 3 is a random magic for now,
+	 * if we DMA timeout more than 3 times, just stay in PIO
+	 */
+	if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
+	    drive->retry_pio <= 3) {
+		drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
+		ide_dma_on(drive);
+	}
+
+	if (!__blk_end_request(rq, error, nr_bytes)) {
+		if (dequeue)
+			HWGROUP(drive)->rq = NULL;
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/**
+ *	ide_end_request		-	complete an IDE I/O
+ *	@drive: IDE device for the I/O
+ *	@uptodate:
+ *	@nr_sectors: number of sectors completed
+ *
+ *	This is our end_request wrapper function. We complete the I/O
+ *	update random number input and dequeue the request, which if
+ *	it was tagged may be out of order.
+ */
+
+int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
+{
+	unsigned int nr_bytes = nr_sectors << 9;
+	struct request *rq;
+	unsigned long flags;
+	int ret = 1;
+
+	/*
+	 * room for locking improvements here, the calls below don't
+	 * need the queue lock held at all
+	 */
+	spin_lock_irqsave(&ide_lock, flags);
+	rq = HWGROUP(drive)->rq;
+
+	if (!nr_bytes) {
+		if (blk_pc_request(rq))
+			nr_bytes = rq->data_len;
+		else
+			nr_bytes = rq->hard_cur_sectors << 9;
+	}
+
+	ret = __ide_end_request(drive, rq, uptodate, nr_bytes, 1);
+
+	spin_unlock_irqrestore(&ide_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(ide_end_request);
+
+static void ide_complete_power_step(ide_drive_t *drive, struct request *rq)
+{
+	struct request_pm_state *pm = rq->data;
+
+#ifdef DEBUG_PM
+	printk(KERN_INFO "%s: complete_power_step(step: %d)\n",
+		drive->name, pm->pm_step);
+#endif
+	if (drive->media != ide_disk)
+		return;
+
+	switch (pm->pm_step) {
+	case IDE_PM_FLUSH_CACHE:	/* Suspend step 1 (flush cache) */
+		if (pm->pm_state == PM_EVENT_FREEZE)
+			pm->pm_step = IDE_PM_COMPLETED;
+		else
+			pm->pm_step = IDE_PM_STANDBY;
+		break;
+	case IDE_PM_STANDBY:		/* Suspend step 2 (standby) */
+		pm->pm_step = IDE_PM_COMPLETED;
+		break;
+	case IDE_PM_RESTORE_PIO:	/* Resume step 1 (restore PIO) */
+		pm->pm_step = IDE_PM_IDLE;
+		break;
+	case IDE_PM_IDLE:		/* Resume step 2 (idle)*/
+		pm->pm_step = IDE_PM_RESTORE_DMA;
+		break;
+	}
+}
+
+static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
+{
+	struct request_pm_state *pm = rq->data;
+	ide_task_t *args = rq->special;
+
+	memset(args, 0, sizeof(*args));
+
+	switch (pm->pm_step) {
+	case IDE_PM_FLUSH_CACHE:	/* Suspend step 1 (flush cache) */
+		if (drive->media != ide_disk)
+			break;
+		/* Not supported? Switch to next step now. */
+		if (ata_id_flush_enabled(drive->id) == 0 ||
+		    (drive->dev_flags & IDE_DFLAG_WCACHE) == 0) {
+			ide_complete_power_step(drive, rq);
+			return ide_stopped;
+		}
+		if (ata_id_flush_ext_enabled(drive->id))
+			args->tf.command = ATA_CMD_FLUSH_EXT;
+		else
+			args->tf.command = ATA_CMD_FLUSH;
+		goto out_do_tf;
+	case IDE_PM_STANDBY:		/* Suspend step 2 (standby) */
+		args->tf.command = ATA_CMD_STANDBYNOW1;
+		goto out_do_tf;
+	case IDE_PM_RESTORE_PIO:	/* Resume step 1 (restore PIO) */
+		ide_set_max_pio(drive);
+		/*
+		 * skip IDE_PM_IDLE for ATAPI devices
+		 */
+		if (drive->media != ide_disk)
+			pm->pm_step = IDE_PM_RESTORE_DMA;
+		else
+			ide_complete_power_step(drive, rq);
+		return ide_stopped;
+	case IDE_PM_IDLE:		/* Resume step 2 (idle) */
+		args->tf.command = ATA_CMD_IDLEIMMEDIATE;
+		goto out_do_tf;
+	case IDE_PM_RESTORE_DMA:	/* Resume step 3 (restore DMA) */
+		/*
+		 * Right now, all we do is call ide_set_dma(drive),
+		 * we could be smarter and check for current xfer_speed
+		 * in struct drive etc...
+		 */
+		if (drive->hwif->dma_ops == NULL)
+			break;
+		/*
+		 * TODO: respect IDE_DFLAG_USING_DMA
+		 */
+		ide_set_dma(drive);
+		break;
+	}
+
+	pm->pm_step = IDE_PM_COMPLETED;
+	return ide_stopped;
+
+out_do_tf:
+	args->tf_flags	 = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
+	args->data_phase = TASKFILE_NO_DATA;
+	return do_rw_taskfile(drive, args);
+}
+
+/**
+ *	ide_end_dequeued_request	-	complete an IDE I/O
+ *	@drive: IDE device for the I/O
+ *	@uptodate:
+ *	@nr_sectors: number of sectors completed
+ *
+ *	Complete an I/O that is no longer on the request queue. This
+ *	typically occurs when we pull the request and issue a REQUEST_SENSE.
+ *	We must still finish the old request but we must not tamper with the
+ *	queue in the meantime.
+ *
+ *	NOTE: This path does not handle barrier, but barrier is not supported
+ *	on ide-cd anyway.
+ */
+
+int ide_end_dequeued_request(ide_drive_t *drive, struct request *rq,
+			     int uptodate, int nr_sectors)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&ide_lock, flags);
+	BUG_ON(!blk_rq_started(rq));
+	ret = __ide_end_request(drive, rq, uptodate, nr_sectors << 9, 0);
+	spin_unlock_irqrestore(&ide_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ide_end_dequeued_request);
+
+
+/**
+ *	ide_complete_pm_request - end the current Power Management request
+ *	@drive: target drive
+ *	@rq: request
+ *
+ *	This function cleans up the current PM request and stops the queue
+ *	if necessary.
+ */
+static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
+{
+	unsigned long flags;
+
+#ifdef DEBUG_PM
+	printk("%s: completing PM request, %s\n", drive->name,
+	       blk_pm_suspend_request(rq) ? "suspend" : "resume");
+#endif
+	spin_lock_irqsave(&ide_lock, flags);
+	if (blk_pm_suspend_request(rq)) {
+		blk_stop_queue(drive->queue);
+	} else {
+		drive->dev_flags &= ~IDE_DFLAG_BLOCKED;
+		blk_start_queue(drive->queue);
+	}
+	HWGROUP(drive)->rq = NULL;
+	if (__blk_end_request(rq, 0, 0))
+		BUG();
+	spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+/**
+ *	ide_end_drive_cmd	-	end an explicit drive command
+ *	@drive: command 
+ *	@stat: status bits
+ *	@err: error bits
+ *
+ *	Clean up after success/failure of an explicit drive command.
+ *	These get thrown onto the queue so they are synchronized with
+ *	real I/O operations on the drive.
+ *
+ *	In LBA48 mode we have to read the register set twice to get
+ *	all the extra information out.
+ */
+ 
+void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
+{
+	unsigned long flags;
+	struct request *rq;
+
+	spin_lock_irqsave(&ide_lock, flags);
+	rq = HWGROUP(drive)->rq;
+	spin_unlock_irqrestore(&ide_lock, flags);
+
+	if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
+		ide_task_t *task = (ide_task_t *)rq->special;
+
+		if (rq->errors == 0)
+			rq->errors = !OK_STAT(stat, ATA_DRDY, BAD_STAT);
+
+		if (task) {
+			struct ide_taskfile *tf = &task->tf;
+
+			tf->error = err;
+			tf->status = stat;
+
+			drive->hwif->tp_ops->tf_read(drive, task);
+
+			if (task->tf_flags & IDE_TFLAG_DYN)
+				kfree(task);
+		}
+	} else if (blk_pm_request(rq)) {
+		struct request_pm_state *pm = rq->data;
+
+		ide_complete_power_step(drive, rq);
+		if (pm->pm_step == IDE_PM_COMPLETED)
+			ide_complete_pm_request(drive, rq);
+		return;
+	}
+
+	spin_lock_irqsave(&ide_lock, flags);
+	HWGROUP(drive)->rq = NULL;
+	rq->errors = err;
+	if (unlikely(__blk_end_request(rq, (rq->errors ? -EIO : 0),
+				       blk_rq_bytes(rq))))
+		BUG();
+	spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+EXPORT_SYMBOL(ide_end_drive_cmd);
+
+static void ide_kill_rq(ide_drive_t *drive, struct request *rq)
+{
+	if (rq->rq_disk) {
+		ide_driver_t *drv;
+
+		drv = *(ide_driver_t **)rq->rq_disk->private_data;
+		drv->end_request(drive, 0, 0);
+	} else
+		ide_end_request(drive, 0, 0);
+}
+
+static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
+{
+	ide_hwif_t *hwif = drive->hwif;
+
+	if ((stat & ATA_BUSY) ||
+	    ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) {
+		/* other bits are useless when BUSY */
+		rq->errors |= ERROR_RESET;
+	} else if (stat & ATA_ERR) {
+		/* err has different meaning on cdrom and tape */
+		if (err == ATA_ABORTED) {
+			if ((drive->dev_flags & IDE_DFLAG_LBA) &&
+			    /* some newer drives don't support ATA_CMD_INIT_DEV_PARAMS */
+			    hwif->tp_ops->read_status(hwif) == ATA_CMD_INIT_DEV_PARAMS)
+				return ide_stopped;
+		} else if ((err & BAD_CRC) == BAD_CRC) {
+			/* UDMA crc error, just retry the operation */
+			drive->crc_count++;
+		} else if (err & (ATA_BBK | ATA_UNC)) {
+			/* retries won't help these */
+			rq->errors = ERROR_MAX;
+		} else if (err & ATA_TRK0NF) {
+			/* help it find track zero */
+			rq->errors |= ERROR_RECAL;
+		}
+	}
+
+	if ((stat & ATA_DRQ) && rq_data_dir(rq) == READ &&
+	    (hwif->host_flags & IDE_HFLAG_ERROR_STOPS_FIFO) == 0) {
+		int nsect = drive->mult_count ? drive->mult_count : 1;
+
+		ide_pad_transfer(drive, READ, nsect * SECTOR_SIZE);
+	}
+
+	if (rq->errors >= ERROR_MAX || blk_noretry_request(rq)) {
+		ide_kill_rq(drive, rq);
+		return ide_stopped;
+	}
+
+	if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
+		rq->errors |= ERROR_RESET;
+
+	if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
+		++rq->errors;
+		return ide_do_reset(drive);
+	}
+
+	if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
+		drive->special.b.recalibrate = 1;
+
+	++rq->errors;
+
+	return ide_stopped;
+}
+
+static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
+{
+	ide_hwif_t *hwif = drive->hwif;
+
+	if ((stat & ATA_BUSY) ||
+	    ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) {
+		/* other bits are useless when BUSY */
+		rq->errors |= ERROR_RESET;
+	} else {
+		/* add decoding error stuff */
+	}
+
+	if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
+		/* force an abort */
+		hwif->tp_ops->exec_command(hwif, ATA_CMD_IDLEIMMEDIATE);
+
+	if (rq->errors >= ERROR_MAX) {
+		ide_kill_rq(drive, rq);
+	} else {
+		if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
+			++rq->errors;
+			return ide_do_reset(drive);
+		}
+		++rq->errors;
+	}
+
+	return ide_stopped;
+}
+
+ide_startstop_t
+__ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
+{
+	if (drive->media == ide_disk)
+		return ide_ata_error(drive, rq, stat, err);
+	return ide_atapi_error(drive, rq, stat, err);
+}
+
+EXPORT_SYMBOL_GPL(__ide_error);
+
+/**
+ *	ide_error	-	handle an error on the IDE
+ *	@drive: drive the error occurred on
+ *	@msg: message to report
+ *	@stat: status bits
+ *
+ *	ide_error() takes action based on the error returned by the drive.
+ *	For normal I/O that may well include retries. We deal with
+ *	both new-style (taskfile) and old style command handling here.
+ *	In the case of taskfile command handling there is work left to
+ *	do
+ */
+ 
+ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat)
+{
+	struct request *rq;
+	u8 err;
+
+	err = ide_dump_status(drive, msg, stat);
+
+	if ((rq = HWGROUP(drive)->rq) == NULL)
+		return ide_stopped;
+
+	/* retry only "normal" I/O: */
+	if (!blk_fs_request(rq)) {
+		rq->errors = 1;
+		ide_end_drive_cmd(drive, stat, err);
+		return ide_stopped;
+	}
+
+	if (rq->rq_disk) {
+		ide_driver_t *drv;
+
+		drv = *(ide_driver_t **)rq->rq_disk->private_data;
+		return drv->error(drive, rq, stat, err);
+	} else
+		return __ide_error(drive, rq, stat, err);
+}
+
+EXPORT_SYMBOL_GPL(ide_error);
+
+static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
+{
+	tf->nsect   = drive->sect;
+	tf->lbal    = drive->sect;
+	tf->lbam    = drive->cyl;
+	tf->lbah    = drive->cyl >> 8;
+	tf->device  = (drive->head - 1) | drive->select;
+	tf->command = ATA_CMD_INIT_DEV_PARAMS;
+}
+
+static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
+{
+	tf->nsect   = drive->sect;
+	tf->command = ATA_CMD_RESTORE;
+}
+
+static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
+{
+	tf->nsect   = drive->mult_req;
+	tf->command = ATA_CMD_SET_MULTI;
+}
+
+static ide_startstop_t ide_disk_special(ide_drive_t *drive)
+{
+	special_t *s = &drive->special;
+	ide_task_t args;
+
+	memset(&args, 0, sizeof(ide_task_t));
+	args.data_phase = TASKFILE_NO_DATA;
+
+	if (s->b.set_geometry) {
+		s->b.set_geometry = 0;
+		ide_tf_set_specify_cmd(drive, &args.tf);
+	} else if (s->b.recalibrate) {
+		s->b.recalibrate = 0;
+		ide_tf_set_restore_cmd(drive, &args.tf);
+	} else if (s->b.set_multmode) {
+		s->b.set_multmode = 0;
+		ide_tf_set_setmult_cmd(drive, &args.tf);
+	} else if (s->all) {
+		int special = s->all;
+		s->all = 0;
+		printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
+		return ide_stopped;
+	}
+
+	args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
+			IDE_TFLAG_CUSTOM_HANDLER;
+
+	do_rw_taskfile(drive, &args);
+
+	return ide_started;
+}
+
+/**
+ *	do_special		-	issue some special commands
+ *	@drive: drive the command is for
+ *
+ *	do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
+ *	ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
+ *
+ *	It used to do much more, but has been scaled back.
+ */
+
+static ide_startstop_t do_special (ide_drive_t *drive)
+{
+	special_t *s = &drive->special;
+
+#ifdef DEBUG
+	printk("%s: do_special: 0x%02x\n", drive->name, s->all);
+#endif
+	if (drive->media == ide_disk)
+		return ide_disk_special(drive);
+
+	s->all = 0;
+	drive->mult_req = 0;
+	return ide_stopped;
+}
+
+void ide_map_sg(ide_drive_t *drive, struct request *rq)
+{
+	ide_hwif_t *hwif = drive->hwif;
+	struct scatterlist *sg = hwif->sg_table;
+
+	if (hwif->sg_mapped)	/* needed by ide-scsi */
+		return;
+
+	if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
+		sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
+		hwif->sg_nents = 1;
+	} else if (!rq->bio) {
+		sg_init_one(sg, rq->data, rq->data_len);
+		hwif->sg_nents = 1;
+	} else {
+		hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
+	}
+}
+
+EXPORT_SYMBOL_GPL(ide_map_sg);
+
+void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq)
+{
+	ide_hwif_t *hwif = drive->hwif;
+
+	hwif->nsect = hwif->nleft = rq->nr_sectors;
+	hwif->cursg_ofs = 0;
+	hwif->cursg = NULL;
+}
+
+EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
+
+/**
+ *	execute_drive_command	-	issue special drive command
+ *	@drive: the drive to issue the command on
+ *	@rq: the request structure holding the command
+ *
+ *	execute_drive_cmd() issues a special drive command,  usually 
+ *	initiated by ioctl() from the external hdparm program. The
+ *	command can be a drive command, drive task or taskfile 
+ *	operation. Weirdly you can call it with NULL to wait for
+ *	all commands to finish. Don't do this as that is due to change
+ */
+
+static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
+		struct request *rq)
+{
+	ide_hwif_t *hwif = HWIF(drive);
+	ide_task_t *task = rq->special;
+
+	if (task) {
+		hwif->data_phase = task->data_phase;
+
+		switch (hwif->data_phase) {
+		case TASKFILE_MULTI_OUT:
+		case TASKFILE_OUT:
+		case TASKFILE_MULTI_IN:
+		case TASKFILE_IN:
+			ide_init_sg_cmd(drive, rq);
+			ide_map_sg(drive, rq);
+		default:
+			break;
+		}
+
+		return do_rw_taskfile(drive, task);
+	}
+
+ 	/*
+ 	 * NULL is actually a valid way of waiting for
+ 	 * all current requests to be flushed from the queue.
+ 	 */
+#ifdef DEBUG
+ 	printk("%s: DRIVE_CMD (null)\n", drive->name);
+#endif
+	ide_end_drive_cmd(drive, hwif->tp_ops->read_status(hwif),
+			  ide_read_error(drive));
+
+ 	return ide_stopped;
+}
+
+int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting,
+		       int arg)
+{
+	struct request_queue *q = drive->queue;
+	struct request *rq;
+	int ret = 0;
+
+	if (!(setting->flags & DS_SYNC))
+		return setting->set(drive, arg);
+
+	rq = blk_get_request(q, READ, __GFP_WAIT);
+	rq->cmd_type = REQ_TYPE_SPECIAL;
+	rq->cmd_len = 5;
+	rq->cmd[0] = REQ_DEVSET_EXEC;
+	*(int *)&rq->cmd[1] = arg;
+	rq->special = setting->set;
+
+	if (blk_execute_rq(q, NULL, rq, 0))
+		ret = rq->errors;
+	blk_put_request(rq);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ide_devset_execute);
+
+static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
+{
+	u8 cmd = rq->cmd[0];
+
+	if (cmd == REQ_PARK_HEADS || cmd == REQ_UNPARK_HEADS) {
+		ide_task_t task;
+		struct ide_taskfile *tf = &task.tf;
+
+		memset(&task, 0, sizeof(task));
+		if (cmd == REQ_PARK_HEADS) {
+			drive->sleep = *(unsigned long *)rq->special;
+			drive->dev_flags |= IDE_DFLAG_SLEEPING;
+			tf->command = ATA_CMD_IDLEIMMEDIATE;
+			tf->feature = 0x44;
+			tf->lbal = 0x4c;
+			tf->lbam = 0x4e;
+			tf->lbah = 0x55;
+			task.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER;
+		} else		/* cmd == REQ_UNPARK_HEADS */
+			tf->command = ATA_CMD_CHK_POWER;
+
+		task.tf_flags |= IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
+		task.rq = rq;
+		drive->hwif->data_phase = task.data_phase = TASKFILE_NO_DATA;
+		return do_rw_taskfile(drive, &task);
+	}
+
+	switch (cmd) {
+	case REQ_DEVSET_EXEC:
+	{
+		int err, (*setfunc)(ide_drive_t *, int) = rq->special;
+
+		err = setfunc(drive, *(int *)&rq->cmd[1]);
+		if (err)
+			rq->errors = err;
+		else
+			err = 1;
+		ide_end_request(drive, err, 0);
+		return ide_stopped;
+	}
+	case REQ_DRIVE_RESET:
+		return ide_do_reset(drive);
+	default:
+		blk_dump_rq_flags(rq, "ide_special_rq - bad request");
+		ide_end_request(drive, 0, 0);
+		return ide_stopped;
+	}
+}
+
+static void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
+{
+	struct request_pm_state *pm = rq->data;
+
+	if (blk_pm_suspend_request(rq) &&
+	    pm->pm_step == IDE_PM_START_SUSPEND)
+		/* Mark drive blocked when starting the suspend sequence. */
+		drive->dev_flags |= IDE_DFLAG_BLOCKED;
+	else if (blk_pm_resume_request(rq) &&
+		 pm->pm_step == IDE_PM_START_RESUME) {
+		/* 
+		 * The first thing we do on wakeup is to wait for BSY bit to
+		 * go away (with a looong timeout) as a drive on this hwif may
+		 * just be POSTing itself.
+		 * We do that before even selecting as the "other" device on
+		 * the bus may be broken enough to walk on our toes at this
+		 * point.
+		 */
+		ide_hwif_t *hwif = drive->hwif;
+		int rc;
+#ifdef DEBUG_PM
+		printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
+#endif
+		rc = ide_wait_not_busy(hwif, 35000);
+		if (rc)
+			printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
+		SELECT_DRIVE(drive);
+		hwif->tp_ops->set_irq(hwif, 1);
+		rc = ide_wait_not_busy(hwif, 100000);
+		if (rc)
+			printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
+	}
+}
+
+/**
+ *	start_request	-	start of I/O and command issuing for IDE
+ *
+ *	start_request() initiates handling of a new I/O request. It
+ *	accepts commands and I/O (read/write) requests.
+ *
+ *	FIXME: this function needs a rename
+ */
+ 
+static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
+{
+	ide_startstop_t startstop;
+
+	BUG_ON(!blk_rq_started(rq));
+
+#ifdef DEBUG
+	printk("%s: start_request: current=0x%08lx\n",
+		HWIF(drive)->name, (unsigned long) rq);
+#endif
+
+	/* bail early if we've exceeded max_failures */
+	if (drive->max_failures && (drive->failures > drive->max_failures)) {
+		rq->cmd_flags |= REQ_FAILED;
+		goto kill_rq;
+	}
+
+	if (blk_pm_request(rq))
+		ide_check_pm_state(drive, rq);
+
+	SELECT_DRIVE(drive);
+	if (ide_wait_stat(&startstop, drive, drive->ready_stat,
+			  ATA_BUSY | ATA_DRQ, WAIT_READY)) {
+		printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
+		return startstop;
+	}
+	if (!drive->special.all) {
+		ide_driver_t *drv;
+
+		/*
+		 * We reset the drive so we need to issue a SETFEATURES.
+		 * Do it _after_ do_special() restored device parameters.
+		 */
+		if (drive->current_speed == 0xff)
+			ide_config_drive_speed(drive, drive->desired_speed);
+
+		if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
+			return execute_drive_cmd(drive, rq);
+		else if (blk_pm_request(rq)) {
+			struct request_pm_state *pm = rq->data;
+#ifdef DEBUG_PM
+			printk("%s: start_power_step(step: %d)\n",
+				drive->name, pm->pm_step);
+#endif
+			startstop = ide_start_power_step(drive, rq);
+			if (startstop == ide_stopped &&
+			    pm->pm_step == IDE_PM_COMPLETED)
+				ide_complete_pm_request(drive, rq);
+			return startstop;
+		} else if (!rq->rq_disk && blk_special_request(rq))
+			/*
+			 * TODO: Once all ULDs have been modified to
+			 * check for specific op codes rather than
+			 * blindly accepting any special request, the
+			 * check for ->rq_disk above may be replaced
+			 * by a more suitable mechanism or even
+			 * dropped entirely.
+			 */
+			return ide_special_rq(drive, rq);
+
+		drv = *(ide_driver_t **)rq->rq_disk->private_data;
+
+		return drv->do_request(drive, rq, rq->sector);
+	}
+	return do_special(drive);
+kill_rq:
+	ide_kill_rq(drive, rq);
+	return ide_stopped;
+}
+
+/**
+ *	ide_stall_queue		-	pause an IDE device
+ *	@drive: drive to stall
+ *	@timeout: time to stall for (jiffies)
+ *
+ *	ide_stall_queue() can be used by a drive to give excess bandwidth back
+ *	to the hwgroup by sleeping for timeout jiffies.
+ */
+ 
+void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
+{
+	if (timeout > WAIT_WORSTCASE)
+		timeout = WAIT_WORSTCASE;
+	drive->sleep = timeout + jiffies;
+	drive->dev_flags |= IDE_DFLAG_SLEEPING;
+}
+
+EXPORT_SYMBOL(ide_stall_queue);
+
+#define WAKEUP(drive)	((drive)->service_start + 2 * (drive)->service_time)
+
+/**
+ *	choose_drive		-	select a drive to service
+ *	@hwgroup: hardware group to select on
+ *
+ *	choose_drive() selects the next drive which will be serviced.
+ *	This is necessary because the IDE layer can't issue commands
+ *	to both drives on the same cable, unlike SCSI.
+ */
+ 
+static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
+{
+	ide_drive_t *drive, *best;
+
+repeat:	
+	best = NULL;
+	drive = hwgroup->drive;
+
+	/*
+	 * drive is doing pre-flush, ordered write, post-flush sequence. even
+	 * though that is 3 requests, it must be seen as a single transaction.
+	 * we must not preempt this drive until that is complete
+	 */
+	if (blk_queue_flushing(drive->queue)) {
+		/*
+		 * small race where queue could get replugged during
+		 * the 3-request flush cycle, just yank the plug since
+		 * we want it to finish asap
+		 */
+		blk_remove_plug(drive->queue);
+		return drive;
+	}
+
+	do {
+		u8 dev_s = !!(drive->dev_flags & IDE_DFLAG_SLEEPING);
+		u8 best_s = (best && !!(best->dev_flags & IDE_DFLAG_SLEEPING));
+
+		if ((dev_s == 0 || time_after_eq(jiffies, drive->sleep)) &&
+		    !elv_queue_empty(drive->queue)) {
+			if (best == NULL ||
+			    (dev_s && (best_s == 0 || time_before(drive->sleep, best->sleep))) ||
+			    (best_s == 0 && time_before(WAKEUP(drive), WAKEUP(best)))) {
+				if (!blk_queue_plugged(drive->queue))
+					best = drive;
+			}
+		}
+	} while ((drive = drive->next) != hwgroup->drive);
+
+	if (best && (best->dev_flags & IDE_DFLAG_NICE1) &&
+	    (best->dev_flags & IDE_DFLAG_SLEEPING) == 0 &&
+	    best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
+		long t = (signed long)(WAKEUP(best) - jiffies);
+		if (t >= WAIT_MIN_SLEEP) {
+		/*
+		 * We *may* have some time to spare, but first let's see if
+		 * someone can potentially benefit from our nice mood today..
+		 */
+			drive = best->next;
+			do {
+				if ((drive->dev_flags & IDE_DFLAG_SLEEPING) == 0
+				 && time_before(jiffies - best->service_time, WAKEUP(drive))
+				 && time_before(WAKEUP(drive), jiffies + t))
+				{
+					ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
+					goto repeat;
+				}
+			} while ((drive = drive->next) != best);
+		}
+	}
+	return best;
+}
+
+/*
+ * Issue a new request to a drive from hwgroup
+ * Caller must have already done spin_lock_irqsave(&ide_lock, ..);
+ *
+ * A hwgroup is a serialized group of IDE interfaces.  Usually there is
+ * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)
+ * may have both interfaces in a single hwgroup to "serialize" access.
+ * Or possibly multiple ISA interfaces can share a common IRQ by being grouped
+ * together into one hwgroup for serialized access.
+ *
+ * Note also that several hwgroups can end up sharing a single IRQ,
+ * possibly along with many other devices.  This is especially common in
+ * PCI-based systems with off-board IDE controller cards.
+ *
+ * The IDE driver uses the single global ide_lock spinlock to protect
+ * access to the request queues, and to protect the hwgroup->busy flag.
+ *
+ * The first thread into the driver for a particular hwgroup sets the
+ * hwgroup->busy flag to indicate that this hwgroup is now active,
+ * and then initiates processing of the top request from the request queue.
+ *
+ * Other threads attempting entry notice the busy setting, and will simply
+ * queue their new requests and exit immediately.  Note that hwgroup->busy
+ * remains set even when the driver is merely awaiting the next interrupt.
+ * Thus, the meaning is "this hwgroup is busy processing a request".
+ *
+ * When processing of a request completes, the completing thread or IRQ-handler
+ * will start the next request from the queue.  If no more work remains,
+ * the driver will clear the hwgroup->busy flag and exit.
+ *
+ * The ide_lock (spinlock) is used to protect all access to the
+ * hwgroup->busy flag, but is otherwise not needed for most processing in
+ * the driver.  This makes the driver much more friendlier to shared IRQs
+ * than previous designs, while remaining 100% (?) SMP safe and capable.
+ */
+static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
+{
+	ide_drive_t	*drive;
+	ide_hwif_t	*hwif;
+	struct request	*rq;
+	ide_startstop_t	startstop;
+	int             loops = 0;
+
+	/* caller must own ide_lock */
+	BUG_ON(!irqs_disabled());
+
+	while (!hwgroup->busy) {
+		hwgroup->busy = 1;
+		/* for atari only */
+		ide_get_lock(ide_intr, hwgroup);
+		drive = choose_drive(hwgroup);
+		if (drive == NULL) {
+			int sleeping = 0;
+			unsigned long sleep = 0; /* shut up, gcc */
+			hwgroup->rq = NULL;
+			drive = hwgroup->drive;
+			do {
+				if ((drive->dev_flags & IDE_DFLAG_SLEEPING) &&
+				    (sleeping == 0 ||
+				     time_before(drive->sleep, sleep))) {
+					sleeping = 1;
+					sleep = drive->sleep;
+				}
+			} while ((drive = drive->next) != hwgroup->drive);
+			if (sleeping) {
+		/*
+		 * Take a short snooze, and then wake up this hwgroup again.
+		 * This gives other hwgroups on the same a chance to
+		 * play fairly with us, just in case there are big differences
+		 * in relative throughputs.. don't want to hog the cpu too much.
+		 */
+				if (time_before(sleep, jiffies + WAIT_MIN_SLEEP))
+					sleep = jiffies + WAIT_MIN_SLEEP;
+#if 1
+				if (timer_pending(&hwgroup->timer))
+					printk(KERN_CRIT "ide_set_handler: timer already active\n");
+#endif
+				/* so that ide_timer_expiry knows what to do */
+				hwgroup->sleeping = 1;
+				hwgroup->req_gen_timer = hwgroup->req_gen;
+				mod_timer(&hwgroup->timer, sleep);
+				/* we purposely leave hwgroup->busy==1
+				 * while sleeping */
+			} else {
+				/* Ugly, but how can we sleep for the lock
+				 * otherwise? perhaps from tq_disk?
+				 */
+
+				/* for atari only */
+				ide_release_lock();
+				hwgroup->busy = 0;
+			}
+
+			/* no more work for this hwgroup (for now) */
+			return;
+		}
+	again:
+		hwif = HWIF(drive);
+		if (hwgroup->hwif->sharing_irq && hwif != hwgroup->hwif) {
+			/*
+			 * set nIEN for previous hwif, drives in the
+			 * quirk_list may not like intr setups/cleanups
+			 */
+			if (drive->quirk_list != 1)
+				hwif->tp_ops->set_irq(hwif, 0);
+		}
+		hwgroup->hwif = hwif;
+		hwgroup->drive = drive;
+		drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
+		drive->service_start = jiffies;
+
+		if (blk_queue_plugged(drive->queue)) {
+			printk(KERN_ERR "ide: huh? queue was plugged!\n");
+			break;
+		}
+
+		/*
+		 * we know that the queue isn't empty, but this can happen
+		 * if the q->prep_rq_fn() decides to kill a request
+		 */
+		rq = elv_next_request(drive->queue);
+		if (!rq) {
+			hwgroup->busy = 0;
+			break;
+		}
+
+		/*
+		 * Sanity: don't accept a request that isn't a PM request
+		 * if we are currently power managed. This is very important as
+		 * blk_stop_queue() doesn't prevent the elv_next_request()
+		 * above to return us whatever is in the queue. Since we call
+		 * ide_do_request() ourselves, we end up taking requests while
+		 * the queue is blocked...
+		 * 
+		 * We let requests forced at head of queue with ide-preempt
+		 * though. I hope that doesn't happen too much, hopefully not
+		 * unless the subdriver triggers such a thing in its own PM
+		 * state machine.
+		 *
+		 * We count how many times we loop here to make sure we service
+		 * all drives in the hwgroup without looping for ever
+		 */
+		if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
+		    blk_pm_request(rq) == 0 &&
+		    (rq->cmd_flags & REQ_PREEMPT) == 0) {
+			drive = drive->next ? drive->next : hwgroup->drive;
+			if (loops++ < 4 && !blk_queue_plugged(drive->queue))
+				goto again;
+			/* We clear busy, there should be no pending ATA command at this point. */
+			hwgroup->busy = 0;
+			break;
+		}
+
+		hwgroup->rq = rq;
+
+		/*
+		 * Some systems have trouble with IDE IRQs arriving while
+		 * the driver is still setting things up.  So, here we disable
+		 * the IRQ used by this interface while the request is being started.
+		 * This may look bad at first, but pretty much the same thing
+		 * happens anyway when any interrupt comes in, IDE or otherwise
+		 *  -- the kernel masks the IRQ while it is being handled.
+		 */
+		if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
+			disable_irq_nosync(hwif->irq);
+		spin_unlock(&ide_lock);
+		local_irq_enable_in_hardirq();
+			/* allow other IRQs while we start this request */
+		startstop = start_request(drive, rq);
+		spin_lock_irq(&ide_lock);
+		if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
+			enable_irq(hwif->irq);
+		if (startstop == ide_stopped)
+			hwgroup->busy = 0;
+	}
+}
+
+/*
+ * Passes the stuff to ide_do_request
+ */
+void do_ide_request(struct request_queue *q)
+{
+	ide_drive_t *drive = q->queuedata;
+
+	ide_do_request(HWGROUP(drive), IDE_NO_IRQ);
+}
+
+/*
+ * un-busy the hwgroup etc, and clear any pending DMA status. we want to
+ * retry the current request in pio mode instead of risking tossing it
+ * all away
+ */
+static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
+{
+	ide_hwif_t *hwif = HWIF(drive);
+	struct request *rq;
+	ide_startstop_t ret = ide_stopped;
+
+	/*
+	 * end current dma transaction
+	 */
+
+	if (error < 0) {
+		printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
+		(void)hwif->dma_ops->dma_end(drive);
+		ret = ide_error(drive, "dma timeout error",
+				hwif->tp_ops->read_status(hwif));
+	} else {
+		printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
+		hwif->dma_ops->dma_timeout(drive);
+	}
+
+	/*
+	 * disable dma for now, but remember that we did so because of
+	 * a timeout -- we'll reenable after we finish this next request
+	 * (or rather the first chunk of it) in pio.
+	 */
+	drive->dev_flags |= IDE_DFLAG_DMA_PIO_RETRY;
+	drive->retry_pio++;
+	ide_dma_off_quietly(drive);
+
+	/*
+	 * un-busy drive etc (hwgroup->busy is cleared on return) and
+	 * make sure request is sane
+	 */
+	rq = HWGROUP(drive)->rq;
+
+	if (!rq)
+		goto out;
+
+	HWGROUP(drive)->rq = NULL;
+
+	rq->errors = 0;
+
+	if (!rq->bio)
+		goto out;
+
+	rq->sector = rq->bio->bi_sector;
+	rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
+	rq->hard_cur_sectors = rq->current_nr_sectors;
+	rq->buffer = bio_data(rq->bio);
+out:
+	return ret;
+}
+
+/**
+ *	ide_timer_expiry	-	handle lack of an IDE interrupt
+ *	@data: timer callback magic (hwgroup)
+ *
+ *	An IDE command has timed out before the expected drive return
+ *	occurred. At this point we attempt to clean up the current
+ *	mess. If the current handler includes an expiry handler then
+ *	we invoke the expiry handler, and providing it is happy the
+ *	work is done. If that fails we apply generic recovery rules
+ *	invoking the handler and checking the drive DMA status. We
+ *	have an excessively incestuous relationship with the DMA
+ *	logic that wants cleaning up.
+ */
+ 
+void ide_timer_expiry (unsigned long data)
+{
+	ide_hwgroup_t	*hwgroup = (ide_hwgroup_t *) data;
+	ide_handler_t	*handler;
+	ide_expiry_t	*expiry;
+	unsigned long	flags;
+	unsigned long	wait = -1;
+
+	spin_lock_irqsave(&ide_lock, flags);
+
+	if (((handler = hwgroup->handler) == NULL) ||
+	    (hwgroup->req_gen != hwgroup->req_gen_timer)) {
+		/*
+		 * Either a marginal timeout occurred
+		 * (got the interrupt just as timer expired),
+		 * or we were "sleeping" to give other devices a chance.
+		 * Either way, we don't really want to complain about anything.
+		 */
+		if (hwgroup->sleeping) {
+			hwgroup->sleeping = 0;
+			hwgroup->busy = 0;
+		}
+	} else {
+		ide_drive_t *drive = hwgroup->drive;
+		if (!drive) {
+			printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
+			hwgroup->handler = NULL;
+		} else {
+			ide_hwif_t *hwif;
+			ide_startstop_t startstop = ide_stopped;
+			if (!hwgroup->busy) {
+				hwgroup->busy = 1;	/* paranoia */
+				printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
+			}
+			if ((expiry = hwgroup->expiry) != NULL) {
+				/* continue */
+				if ((wait = expiry(drive)) > 0) {
+					/* reset timer */
+					hwgroup->timer.expires  = jiffies + wait;
+					hwgroup->req_gen_timer = hwgroup->req_gen;
+					add_timer(&hwgroup->timer);
+					spin_unlock_irqrestore(&ide_lock, flags);
+					return;
+				}
+			}
+			hwgroup->handler = NULL;
+			/*
+			 * We need to simulate a real interrupt when invoking
+			 * the handler() function, which means we need to
+			 * globally mask the specific IRQ:
+			 */
+			spin_unlock(&ide_lock);
+			hwif  = HWIF(drive);
+			/* disable_irq_nosync ?? */
+			disable_irq(hwif->irq);
+			/* local CPU only,
+			 * as if we were handling an interrupt */
+			local_irq_disable();
+			if (hwgroup->polling) {
+				startstop = handler(drive);
+			} else if (drive_is_ready(drive)) {
+				if (drive->waiting_for_dma)
+					hwif->dma_ops->dma_lost_irq(drive);
+				(void)ide_ack_intr(hwif);
+				printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
+				startstop = handler(drive);
+			} else {
+				if (drive->waiting_for_dma) {
+					startstop = ide_dma_timeout_retry(drive, wait);
+				} else
+					startstop =
+					ide_error(drive, "irq timeout",
+						  hwif->tp_ops->read_status(hwif));
+			}
+			drive->service_time = jiffies - drive->service_start;
+			spin_lock_irq(&ide_lock);
+			enable_irq(hwif->irq);
+			if (startstop == ide_stopped)
+				hwgroup->busy = 0;
+		}
+	}
+	ide_do_request(hwgroup, IDE_NO_IRQ);
+	spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+/**
+ *	unexpected_intr		-	handle an unexpected IDE interrupt
+ *	@irq: interrupt line
+ *	@hwgroup: hwgroup being processed
+ *
+ *	There's nothing really useful we can do with an unexpected interrupt,
+ *	other than reading the status register (to clear it), and logging it.
+ *	There should be no way that an irq can happen before we're ready for it,
+ *	so we needn't worry much about losing an "important" interrupt here.
+ *
+ *	On laptops (and "green" PCs), an unexpected interrupt occurs whenever
+ *	the drive enters "idle", "standby", or "sleep" mode, so if the status
+ *	looks "good", we just ignore the interrupt completely.
+ *
+ *	This routine assumes __cli() is in effect when called.
+ *
+ *	If an unexpected interrupt happens on irq15 while we are handling irq14
+ *	and if the two interfaces are "serialized" (CMD640), then it looks like
+ *	we could screw up by interfering with a new request being set up for 
+ *	irq15.
+ *
+ *	In reality, this is a non-issue.  The new command is not sent unless 
+ *	the drive is ready to accept one, in which case we know the drive is
+ *	not trying to interrupt us.  And ide_set_handler() is always invoked
+ *	before completing the issuance of any new drive command, so we will not
+ *	be accidentally invoked as a result of any valid command completion
+ *	interrupt.
+ *
+ *	Note that we must walk the entire hwgroup here. We know which hwif
+ *	is doing the current command, but we don't know which hwif burped
+ *	mysteriously.
+ */
+ 
+static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
+{
+	u8 stat;
+	ide_hwif_t *hwif = hwgroup->hwif;
+
+	/*
+	 * handle the unexpected interrupt
+	 */
+	do {
+		if (hwif->irq == irq) {
+			stat = hwif->tp_ops->read_status(hwif);
+
+			if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
+				/* Try to not flood the console with msgs */
+				static unsigned long last_msgtime, count;
+				++count;
+				if (time_after(jiffies, last_msgtime + HZ)) {
+					last_msgtime = jiffies;
+					printk(KERN_ERR "%s%s: unexpected interrupt, "
+						"status=0x%02x, count=%ld\n",
+						hwif->name,
+						(hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
+				}
+			}
+		}
+	} while ((hwif = hwif->next) != hwgroup->hwif);
+}
+
+/**
+ *	ide_intr	-	default IDE interrupt handler
+ *	@irq: interrupt number
+ *	@dev_id: hwif group
+ *	@regs: unused weirdness from the kernel irq layer
+ *
+ *	This is the default IRQ handler for the IDE layer. You should
+ *	not need to override it. If you do be aware it is subtle in
+ *	places
+ *
+ *	hwgroup->hwif is the interface in the group currently performing
+ *	a command. hwgroup->drive is the drive and hwgroup->handler is
+ *	the IRQ handler to call. As we issue a command the handlers
+ *	step through multiple states, reassigning the handler to the
+ *	next step in the process. Unlike a smart SCSI controller IDE
+ *	expects the main processor to sequence the various transfer
+ *	stages. We also manage a poll timer to catch up with most
+ *	timeout situations. There are still a few where the handlers
+ *	don't ever decide to give up.
+ *
+ *	The handler eventually returns ide_stopped to indicate the
+ *	request completed. At this point we issue the next request
+ *	on the hwgroup and the process begins again.
+ */
+ 
+irqreturn_t ide_intr (int irq, void *dev_id)
+{
+	unsigned long flags;
+	ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
+	ide_hwif_t *hwif;
+	ide_drive_t *drive;
+	ide_handler_t *handler;
+	ide_startstop_t startstop;
+
+	spin_lock_irqsave(&ide_lock, flags);
+	hwif = hwgroup->hwif;
+
+	if (!ide_ack_intr(hwif)) {
+		spin_unlock_irqrestore(&ide_lock, flags);
+		return IRQ_NONE;
+	}
+
+	if ((handler = hwgroup->handler) == NULL || hwgroup->polling) {
+		/*
+		 * Not expecting an interrupt from this drive.
+		 * That means this could be:
+		 *	(1) an interrupt from another PCI device
+		 *	sharing the same PCI INT# as us.
+		 * or	(2) a drive just entered sleep or standby mode,
+		 *	and is interrupting to let us know.
+		 * or	(3) a spurious interrupt of unknown origin.
+		 *
+		 * For PCI, we cannot tell the difference,
+		 * so in that case we just ignore it and hope it goes away.
+		 *
+		 * FIXME: unexpected_intr should be hwif-> then we can
+		 * remove all the ifdef PCI crap
+		 */
+#ifdef CONFIG_BLK_DEV_IDEPCI
+		if (hwif->chipset != ide_pci)
+#endif	/* CONFIG_BLK_DEV_IDEPCI */
+		{
+			/*
+			 * Probably not a shared PCI interrupt,
+			 * so we can safely try to do something about it:
+			 */
+			unexpected_intr(irq, hwgroup);
+#ifdef CONFIG_BLK_DEV_IDEPCI
+		} else {
+			/*
+			 * Whack the status register, just in case
+			 * we have a leftover pending IRQ.
+			 */
+			(void)hwif->tp_ops->read_status(hwif);
+#endif /* CONFIG_BLK_DEV_IDEPCI */
+		}
+		spin_unlock_irqrestore(&ide_lock, flags);
+		return IRQ_NONE;
+	}
+	drive = hwgroup->drive;
+	if (!drive) {
+		/*
+		 * This should NEVER happen, and there isn't much
+		 * we could do about it here.
+		 *
+		 * [Note - this can occur if the drive is hot unplugged]
+		 */
+		spin_unlock_irqrestore(&ide_lock, flags);
+		return IRQ_HANDLED;
+	}
+	if (!drive_is_ready(drive)) {
+		/*
+		 * This happens regularly when we share a PCI IRQ with
+		 * another device.  Unfortunately, it can also happen
+		 * with some buggy drives that trigger the IRQ before
+		 * their status register is up to date.  Hopefully we have
+		 * enough advance overhead that the latter isn't a problem.
+		 */
+		spin_unlock_irqrestore(&ide_lock, flags);
+		return IRQ_NONE;
+	}
+	if (!hwgroup->busy) {
+		hwgroup->busy = 1;	/* paranoia */
+		printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
+	}
+	hwgroup->handler = NULL;
+	hwgroup->req_gen++;
+	del_timer(&hwgroup->timer);
+	spin_unlock(&ide_lock);
+
+	if (hwif->port_ops && hwif->port_ops->clear_irq)
+		hwif->port_ops->clear_irq(drive);
+
+	if (drive->dev_flags & IDE_DFLAG_UNMASK)
+		local_irq_enable_in_hardirq();
+
+	/* service this interrupt, may set handler for next interrupt */
+	startstop = handler(drive);
+
+	spin_lock_irq(&ide_lock);
+	/*
+	 * Note that handler() may have set things up for another
+	 * interrupt to occur soon, but it cannot happen until
+	 * we exit from this routine, because it will be the
+	 * same irq as is currently being serviced here, and Linux
+	 * won't allow another of the same (on any CPU) until we return.
+	 */
+	drive->service_time = jiffies - drive->service_start;
+	if (startstop == ide_stopped) {
+		if (hwgroup->handler == NULL) {	/* paranoia */
+			hwgroup->busy = 0;
+			ide_do_request(hwgroup, hwif->irq);
+		} else {
+			printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
+				"on exit\n", drive->name);
+		}
+	}
+	spin_unlock_irqrestore(&ide_lock, flags);
+	return IRQ_HANDLED;
+}
+
+/**
+ *	ide_do_drive_cmd	-	issue IDE special command
+ *	@drive: device to issue command
+ *	@rq: request to issue
+ *
+ *	This function issues a special IDE device request
+ *	onto the request queue.
+ *
+ *	the rq is queued at the head of the request queue, displacing
+ *	the currently-being-processed request and this function
+ *	returns immediately without waiting for the new rq to be
+ *	completed.  This is VERY DANGEROUS, and is intended for
+ *	careful use by the ATAPI tape/cdrom driver code.
+ */
+
+void ide_do_drive_cmd(ide_drive_t *drive, struct request *rq)
+{
+	unsigned long flags;
+	ide_hwgroup_t *hwgroup = HWGROUP(drive);
+
+	spin_lock_irqsave(&ide_lock, flags);
+	hwgroup->rq = NULL;
+	__elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 0);
+	blk_start_queueing(drive->queue);
+	spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+EXPORT_SYMBOL(ide_do_drive_cmd);
+
+void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount, u8 dma)
+{
+	ide_hwif_t *hwif = drive->hwif;
+	ide_task_t task;
+
+	memset(&task, 0, sizeof(task));
+	task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM |
+			IDE_TFLAG_OUT_FEATURE | tf_flags;
+	task.tf.feature = dma;		/* Use PIO/DMA */
+	task.tf.lbam    = bcount & 0xff;
+	task.tf.lbah    = (bcount >> 8) & 0xff;
+
+	ide_tf_dump(drive->name, &task.tf);
+	hwif->tp_ops->set_irq(hwif, 1);
+	SELECT_MASK(drive, 0);
+	hwif->tp_ops->tf_load(drive, &task);
+}
+
+EXPORT_SYMBOL_GPL(ide_pktcmd_tf_load);
+
+void ide_pad_transfer(ide_drive_t *drive, int write, int len)
+{
+	ide_hwif_t *hwif = drive->hwif;
+	u8 buf[4] = { 0 };
+
+	while (len > 0) {
+		if (write)
+			hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
+		else
+			hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
+		len -= 4;
+	}
+}
+EXPORT_SYMBOL_GPL(ide_pad_transfer);