Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1681 insertions, 0 deletions

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
new file mode 100644
index 00000000000..248e3cc8b35
--- /dev/null
+++ b/drivers/ide/ide-io.c
@@ -0,0 +1,1681 @@
+/*
+ *	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/config.h>
+#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/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 <asm/byteorder.h>
+#include <asm/irq.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/bitops.h>
+
+int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate,
+		      int nr_sectors)
+{
+	int ret = 1;
+
+	BUG_ON(!(rq->flags & REQ_STARTED));
+
+	/*
+	 * if failfast is set on a request, override number of sectors and
+	 * complete the whole request right now
+	 */
+	if (blk_noretry_request(rq) && end_io_error(uptodate))
+		nr_sectors = rq->hard_nr_sectors;
+
+	if (!blk_fs_request(rq) && end_io_error(uptodate) && !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->state == DMA_PIO_RETRY && drive->retry_pio <= 3) {
+		drive->state = 0;
+		HWGROUP(drive)->hwif->ide_dma_on(drive);
+	}
+
+	if (!end_that_request_first(rq, uptodate, nr_sectors)) {
+		add_disk_randomness(rq->rq_disk);
+
+		if (blk_rq_tagged(rq))
+			blk_queue_end_tag(drive->queue, rq);
+
+		blkdev_dequeue_request(rq);
+		HWGROUP(drive)->rq = NULL;
+		end_that_request_last(rq);
+		ret = 0;
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__ide_end_request);
+
+/**
+ *	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)
+{
+	struct request *rq;
+	unsigned long flags;
+	int ret = 1;
+
+	spin_lock_irqsave(&ide_lock, flags);
+	rq = HWGROUP(drive)->rq;
+
+	if (!nr_sectors)
+		nr_sectors = rq->hard_cur_sectors;
+
+	if (blk_complete_barrier_rq_locked(drive->queue, rq, nr_sectors))
+		ret = rq->nr_sectors != 0;
+	else
+		ret = __ide_end_request(drive, rq, uptodate, nr_sectors);
+
+	spin_unlock_irqrestore(&ide_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(ide_end_request);
+
+/*
+ * Power Management state machine. This one is rather trivial for now,
+ * we should probably add more, like switching back to PIO on suspend
+ * to help some BIOSes, re-do the door locking on resume, etc...
+ */
+
+enum {
+	ide_pm_flush_cache	= ide_pm_state_start_suspend,
+	idedisk_pm_standby,
+
+	idedisk_pm_idle		= ide_pm_state_start_resume,
+	ide_pm_restore_dma,
+};
+
+static void ide_complete_power_step(ide_drive_t *drive, struct request *rq, u8 stat, u8 error)
+{
+	if (drive->media != ide_disk)
+		return;
+
+	switch (rq->pm->pm_step) {
+	case ide_pm_flush_cache:	/* Suspend step 1 (flush cache) complete */
+		if (rq->pm->pm_state == 4)
+			rq->pm->pm_step = ide_pm_state_completed;
+		else
+			rq->pm->pm_step = idedisk_pm_standby;
+		break;
+	case idedisk_pm_standby:	/* Suspend step 2 (standby) complete */
+		rq->pm->pm_step = ide_pm_state_completed;
+		break;
+	case idedisk_pm_idle:		/* Resume step 1 (idle) complete */
+		rq->pm->pm_step = ide_pm_restore_dma;
+		break;
+	}
+}
+
+static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
+{
+	ide_task_t *args = rq->special;
+
+	memset(args, 0, sizeof(*args));
+
+	if (drive->media != ide_disk) {
+		/* skip idedisk_pm_idle for ATAPI devices */
+		if (rq->pm->pm_step == idedisk_pm_idle)
+			rq->pm->pm_step = ide_pm_restore_dma;
+	}
+
+	switch (rq->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 (!drive->wcache || !ide_id_has_flush_cache(drive->id)) {
+			ide_complete_power_step(drive, rq, 0, 0);
+			return ide_stopped;
+		}
+		if (ide_id_has_flush_cache_ext(drive->id))
+			args->tfRegister[IDE_COMMAND_OFFSET] = WIN_FLUSH_CACHE_EXT;
+		else
+			args->tfRegister[IDE_COMMAND_OFFSET] = WIN_FLUSH_CACHE;
+		args->command_type = IDE_DRIVE_TASK_NO_DATA;
+		args->handler	   = &task_no_data_intr;
+		return do_rw_taskfile(drive, args);
+
+	case idedisk_pm_standby:	/* Suspend step 2 (standby) */
+		args->tfRegister[IDE_COMMAND_OFFSET] = WIN_STANDBYNOW1;
+		args->command_type = IDE_DRIVE_TASK_NO_DATA;
+		args->handler	   = &task_no_data_intr;
+		return do_rw_taskfile(drive, args);
+
+	case idedisk_pm_idle:		/* Resume step 1 (idle) */
+		args->tfRegister[IDE_COMMAND_OFFSET] = WIN_IDLEIMMEDIATE;
+		args->command_type = IDE_DRIVE_TASK_NO_DATA;
+		args->handler = task_no_data_intr;
+		return do_rw_taskfile(drive, args);
+
+	case ide_pm_restore_dma:	/* Resume step 2 (restore DMA) */
+		/*
+		 * Right now, all we do is call hwif->ide_dma_check(drive),
+		 * we could be smarter and check for current xfer_speed
+		 * in struct drive etc...
+		 */
+		if ((drive->id->capability & 1) == 0)
+			break;
+		if (drive->hwif->ide_dma_check == NULL)
+			break;
+		drive->hwif->ide_dma_check(drive);
+		break;
+	}
+	rq->pm->pm_step = ide_pm_state_completed;
+	return ide_stopped;
+}
+
+/**
+ *	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->blocked = 0;
+		blk_start_queue(drive->queue);
+	}
+	blkdev_dequeue_request(rq);
+	HWGROUP(drive)->rq = NULL;
+	end_that_request_last(rq);
+	spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+/*
+ * FIXME: probably move this somewhere else, name is bad too :)
+ */
+u64 ide_get_error_location(ide_drive_t *drive, char *args)
+{
+	u32 high, low;
+	u8 hcyl, lcyl, sect;
+	u64 sector;
+
+	high = 0;
+	hcyl = args[5];
+	lcyl = args[4];
+	sect = args[3];
+
+	if (ide_id_has_flush_cache_ext(drive->id)) {
+		low = (hcyl << 16) | (lcyl << 8) | sect;
+		HWIF(drive)->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
+		high = ide_read_24(drive);
+	} else {
+		u8 cur = HWIF(drive)->INB(IDE_SELECT_REG);
+		if (cur & 0x40) {
+			high = cur & 0xf;
+			low = (hcyl << 16) | (lcyl << 8) | sect;
+		} else {
+			low = hcyl * drive->head * drive->sect;
+			low += lcyl * drive->sect;
+			low += sect - 1;
+		}
+	}
+
+	sector = ((u64) high << 24) | low;
+	return sector;
+}
+EXPORT_SYMBOL(ide_get_error_location);
+
+/**
+ *	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)
+{
+	ide_hwif_t *hwif = HWIF(drive);
+	unsigned long flags;
+	struct request *rq;
+
+	spin_lock_irqsave(&ide_lock, flags);
+	rq = HWGROUP(drive)->rq;
+	spin_unlock_irqrestore(&ide_lock, flags);
+
+	if (rq->flags & REQ_DRIVE_CMD) {
+		u8 *args = (u8 *) rq->buffer;
+		if (rq->errors == 0)
+			rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
+
+		if (args) {
+			args[0] = stat;
+			args[1] = err;
+			args[2] = hwif->INB(IDE_NSECTOR_REG);
+		}
+	} else if (rq->flags & REQ_DRIVE_TASK) {
+		u8 *args = (u8 *) rq->buffer;
+		if (rq->errors == 0)
+			rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
+
+		if (args) {
+			args[0] = stat;
+			args[1] = err;
+			args[2] = hwif->INB(IDE_NSECTOR_REG);
+			args[3] = hwif->INB(IDE_SECTOR_REG);
+			args[4] = hwif->INB(IDE_LCYL_REG);
+			args[5] = hwif->INB(IDE_HCYL_REG);
+			args[6] = hwif->INB(IDE_SELECT_REG);
+		}
+	} else if (rq->flags & REQ_DRIVE_TASKFILE) {
+		ide_task_t *args = (ide_task_t *) rq->special;
+		if (rq->errors == 0)
+			rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
+			
+		if (args) {
+			if (args->tf_in_flags.b.data) {
+				u16 data				= hwif->INW(IDE_DATA_REG);
+				args->tfRegister[IDE_DATA_OFFSET]	= (data) & 0xFF;
+				args->hobRegister[IDE_DATA_OFFSET]	= (data >> 8) & 0xFF;
+			}
+			args->tfRegister[IDE_ERROR_OFFSET]   = err;
+			/* be sure we're looking at the low order bits */
+			hwif->OUTB(drive->ctl & ~0x80, IDE_CONTROL_REG);
+			args->tfRegister[IDE_NSECTOR_OFFSET] = hwif->INB(IDE_NSECTOR_REG);
+			args->tfRegister[IDE_SECTOR_OFFSET]  = hwif->INB(IDE_SECTOR_REG);
+			args->tfRegister[IDE_LCYL_OFFSET]    = hwif->INB(IDE_LCYL_REG);
+			args->tfRegister[IDE_HCYL_OFFSET]    = hwif->INB(IDE_HCYL_REG);
+			args->tfRegister[IDE_SELECT_OFFSET]  = hwif->INB(IDE_SELECT_REG);
+			args->tfRegister[IDE_STATUS_OFFSET]  = stat;
+
+			if (drive->addressing == 1) {
+				hwif->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
+				args->hobRegister[IDE_FEATURE_OFFSET]	= hwif->INB(IDE_FEATURE_REG);
+				args->hobRegister[IDE_NSECTOR_OFFSET]	= hwif->INB(IDE_NSECTOR_REG);
+				args->hobRegister[IDE_SECTOR_OFFSET]	= hwif->INB(IDE_SECTOR_REG);
+				args->hobRegister[IDE_LCYL_OFFSET]	= hwif->INB(IDE_LCYL_REG);
+				args->hobRegister[IDE_HCYL_OFFSET]	= hwif->INB(IDE_HCYL_REG);
+			}
+		}
+	} else if (blk_pm_request(rq)) {
+#ifdef DEBUG_PM
+		printk("%s: complete_power_step(step: %d, stat: %x, err: %x)\n",
+			drive->name, rq->pm->pm_step, stat, err);
+#endif
+		ide_complete_power_step(drive, rq, stat, err);
+		if (rq->pm->pm_step == ide_pm_state_completed)
+			ide_complete_pm_request(drive, rq);
+		return;
+	}
+
+	spin_lock_irqsave(&ide_lock, flags);
+	blkdev_dequeue_request(rq);
+	HWGROUP(drive)->rq = NULL;
+	rq->errors = err;
+	end_that_request_last(rq);
+	spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+EXPORT_SYMBOL(ide_end_drive_cmd);
+
+/**
+ *	try_to_flush_leftover_data	-	flush junk
+ *	@drive: drive to flush
+ *
+ *	try_to_flush_leftover_data() is invoked in response to a drive
+ *	unexpectedly having its DRQ_STAT bit set.  As an alternative to
+ *	resetting the drive, this routine tries to clear the condition
+ *	by read a sector's worth of data from the drive.  Of course,
+ *	this may not help if the drive is *waiting* for data from *us*.
+ */
+static void try_to_flush_leftover_data (ide_drive_t *drive)
+{
+	int i = (drive->mult_count ? drive->mult_count : 1) * SECTOR_WORDS;
+
+	if (drive->media != ide_disk)
+		return;
+	while (i > 0) {
+		u32 buffer[16];
+		u32 wcount = (i > 16) ? 16 : i;
+
+		i -= wcount;
+		HWIF(drive)->ata_input_data(drive, buffer, wcount);
+	}
+}
+
+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 & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) {
+		/* other bits are useless when BUSY */
+		rq->errors |= ERROR_RESET;
+	} else if (stat & ERR_STAT) {
+		/* err has different meaning on cdrom and tape */
+		if (err == ABRT_ERR) {
+			if (drive->select.b.lba &&
+			    /* some newer drives don't support WIN_SPECIFY */
+			    hwif->INB(IDE_COMMAND_REG) == WIN_SPECIFY)
+				return ide_stopped;
+		} else if ((err & BAD_CRC) == BAD_CRC) {
+			/* UDMA crc error, just retry the operation */
+			drive->crc_count++;
+		} else if (err & (BBD_ERR | ECC_ERR)) {
+			/* retries won't help these */
+			rq->errors = ERROR_MAX;
+		} else if (err & TRK0_ERR) {
+			/* help it find track zero */
+			rq->errors |= ERROR_RECAL;
+		}
+	}
+
+	if ((stat & DRQ_STAT) && rq_data_dir(rq) == READ)
+		try_to_flush_leftover_data(drive);
+
+	if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT))
+		/* force an abort */
+		hwif->OUTB(WIN_IDLEIMMEDIATE, IDE_COMMAND_REG);
+
+	if (rq->errors >= ERROR_MAX || blk_noretry_request(rq))
+		ide_kill_rq(drive, rq);
+	else {
+		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 & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) {
+		/* other bits are useless when BUSY */
+		rq->errors |= ERROR_RESET;
+	} else {
+		/* add decoding error stuff */
+	}
+
+	if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT))
+		/* force an abort */
+		hwif->OUTB(WIN_IDLEIMMEDIATE, IDE_COMMAND_REG);
+
+	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 (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK | REQ_DRIVE_TASKFILE)) {
+		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);
+
+ide_startstop_t __ide_abort(ide_drive_t *drive, struct request *rq)
+{
+	if (drive->media != ide_disk)
+		rq->errors |= ERROR_RESET;
+
+	ide_kill_rq(drive, rq);
+
+	return ide_stopped;
+}
+
+EXPORT_SYMBOL_GPL(__ide_abort);
+
+/**
+ *	ide_abort	-	abort pending IDE operatins
+ *	@drive: drive the error occurred on
+ *	@msg: message to report
+ *
+ *	ide_abort kills and cleans up when we are about to do a 
+ *	host initiated reset on active commands. Longer term we
+ *	want handlers to have sensible abort handling themselves
+ *
+ *	This differs fundamentally from ide_error because in 
+ *	this case the command is doing just fine when we
+ *	blow it away.
+ */
+ 
+ide_startstop_t ide_abort(ide_drive_t *drive, const char *msg)
+{
+	struct request *rq;
+
+	if (drive == NULL || (rq = HWGROUP(drive)->rq) == NULL)
+		return ide_stopped;
+
+	/* retry only "normal" I/O: */
+	if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK | REQ_DRIVE_TASKFILE)) {
+		rq->errors = 1;
+		ide_end_drive_cmd(drive, BUSY_STAT, 0);
+		return ide_stopped;
+	}
+
+	if (rq->rq_disk) {
+		ide_driver_t *drv;
+
+		drv = *(ide_driver_t **)rq->rq_disk->private_data;
+		return drv->abort(drive, rq);
+	} else
+		return __ide_abort(drive, rq);
+}
+
+/**
+ *	ide_cmd		-	issue a simple drive command
+ *	@drive: drive the command is for
+ *	@cmd: command byte
+ *	@nsect: sector byte
+ *	@handler: handler for the command completion
+ *
+ *	Issue a simple drive command with interrupts.
+ *	The drive must be selected beforehand.
+ */
+
+static void ide_cmd (ide_drive_t *drive, u8 cmd, u8 nsect,
+		ide_handler_t *handler)
+{
+	ide_hwif_t *hwif = HWIF(drive);
+	if (IDE_CONTROL_REG)
+		hwif->OUTB(drive->ctl,IDE_CONTROL_REG);	/* clear nIEN */
+	SELECT_MASK(drive,0);
+	hwif->OUTB(nsect,IDE_NSECTOR_REG);
+	ide_execute_command(drive, cmd, handler, WAIT_CMD, NULL);
+}
+
+/**
+ *	drive_cmd_intr		- 	drive command completion interrupt
+ *	@drive: drive the completion interrupt occurred on
+ *
+ *	drive_cmd_intr() is invoked on completion of a special DRIVE_CMD.
+ *	We do any necessary daya reading and then wait for the drive to
+ *	go non busy. At that point we may read the error data and complete
+ *	the request
+ */
+ 
+static ide_startstop_t drive_cmd_intr (ide_drive_t *drive)
+{
+	struct request *rq = HWGROUP(drive)->rq;
+	ide_hwif_t *hwif = HWIF(drive);
+	u8 *args = (u8 *) rq->buffer;
+	u8 stat = hwif->INB(IDE_STATUS_REG);
+	int retries = 10;
+
+	local_irq_enable();
+	if ((stat & DRQ_STAT) && args && args[3]) {
+		u8 io_32bit = drive->io_32bit;
+		drive->io_32bit = 0;
+		hwif->ata_input_data(drive, &args[4], args[3] * SECTOR_WORDS);
+		drive->io_32bit = io_32bit;
+		while (((stat = hwif->INB(IDE_STATUS_REG)) & BUSY_STAT) && retries--)
+			udelay(100);
+	}
+
+	if (!OK_STAT(stat, READY_STAT, BAD_STAT))
+		return ide_error(drive, "drive_cmd", stat);
+		/* calls ide_end_drive_cmd */
+	ide_end_drive_cmd(drive, stat, hwif->INB(IDE_ERROR_REG));
+	return ide_stopped;
+}
+
+static void ide_init_specify_cmd(ide_drive_t *drive, ide_task_t *task)
+{
+	task->tfRegister[IDE_NSECTOR_OFFSET] = drive->sect;
+	task->tfRegister[IDE_SECTOR_OFFSET]  = drive->sect;
+	task->tfRegister[IDE_LCYL_OFFSET]    = drive->cyl;
+	task->tfRegister[IDE_HCYL_OFFSET]    = drive->cyl>>8;
+	task->tfRegister[IDE_SELECT_OFFSET]  = ((drive->head-1)|drive->select.all)&0xBF;
+	task->tfRegister[IDE_COMMAND_OFFSET] = WIN_SPECIFY;
+
+	task->handler = &set_geometry_intr;
+}
+
+static void ide_init_restore_cmd(ide_drive_t *drive, ide_task_t *task)
+{
+	task->tfRegister[IDE_NSECTOR_OFFSET] = drive->sect;
+	task->tfRegister[IDE_COMMAND_OFFSET] = WIN_RESTORE;
+
+	task->handler = &recal_intr;
+}
+
+static void ide_init_setmult_cmd(ide_drive_t *drive, ide_task_t *task)
+{
+	task->tfRegister[IDE_NSECTOR_OFFSET] = drive->mult_req;
+	task->tfRegister[IDE_COMMAND_OFFSET] = WIN_SETMULT;
+
+	task->handler = &set_multmode_intr;
+}
+
+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.command_type = IDE_DRIVE_TASK_NO_DATA;
+
+	if (s->b.set_geometry) {
+		s->b.set_geometry = 0;
+		ide_init_specify_cmd(drive, &args);
+	} else if (s->b.recalibrate) {
+		s->b.recalibrate = 0;
+		ide_init_restore_cmd(drive, &args);
+	} else if (s->b.set_multmode) {
+		s->b.set_multmode = 0;
+		if (drive->mult_req > drive->id->max_multsect)
+			drive->mult_req = drive->id->max_multsect;
+		ide_init_setmult_cmd(drive, &args);
+	} 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;
+	}
+
+	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 WIN_SPECIFY, WIN_RESTORE, and WIN_SETMULT
+ *	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 (s->b.set_tune) {
+		s->b.set_tune = 0;
+		if (HWIF(drive)->tuneproc != NULL)
+			HWIF(drive)->tuneproc(drive, drive->tune_req);
+		return ide_stopped;
+	} else {
+		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->flags & REQ_DRIVE_TASKFILE) == 0) {
+		hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
+	} else {
+		sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
+		hwif->sg_nents = 1;
+	}
+}
+
+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 = hwif->cursg_ofs = 0;
+}
+
+EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
+
+/**
+ *	execute_drive_command	-	issue special drive command
+ *	@drive: the drive to issue th 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);
+	if (rq->flags & REQ_DRIVE_TASKFILE) {
+ 		ide_task_t *args = rq->special;
+ 
+		if (!args)
+			goto done;
+
+		hwif->data_phase = args->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;
+		}
+
+		if (args->tf_out_flags.all != 0) 
+			return flagged_taskfile(drive, args);
+		return do_rw_taskfile(drive, args);
+	} else if (rq->flags & REQ_DRIVE_TASK) {
+		u8 *args = rq->buffer;
+		u8 sel;
+ 
+		if (!args)
+			goto done;
+#ifdef DEBUG
+ 		printk("%s: DRIVE_TASK_CMD ", drive->name);
+ 		printk("cmd=0x%02x ", args[0]);
+ 		printk("fr=0x%02x ", args[1]);
+ 		printk("ns=0x%02x ", args[2]);
+ 		printk("sc=0x%02x ", args[3]);
+ 		printk("lcyl=0x%02x ", args[4]);
+ 		printk("hcyl=0x%02x ", args[5]);
+ 		printk("sel=0x%02x\n", args[6]);
+#endif
+ 		hwif->OUTB(args[1], IDE_FEATURE_REG);
+ 		hwif->OUTB(args[3], IDE_SECTOR_REG);
+ 		hwif->OUTB(args[4], IDE_LCYL_REG);
+ 		hwif->OUTB(args[5], IDE_HCYL_REG);
+ 		sel = (args[6] & ~0x10);
+ 		if (drive->select.b.unit)
+ 			sel |= 0x10;
+ 		hwif->OUTB(sel, IDE_SELECT_REG);
+ 		ide_cmd(drive, args[0], args[2], &drive_cmd_intr);
+ 		return ide_started;
+ 	} else if (rq->flags & REQ_DRIVE_CMD) {
+ 		u8 *args = rq->buffer;
+
+		if (!args)
+			goto done;
+#ifdef DEBUG
+ 		printk("%s: DRIVE_CMD ", drive->name);
+ 		printk("cmd=0x%02x ", args[0]);
+ 		printk("sc=0x%02x ", args[1]);
+ 		printk("fr=0x%02x ", args[2]);
+ 		printk("xx=0x%02x\n", args[3]);
+#endif
+ 		if (args[0] == WIN_SMART) {
+ 			hwif->OUTB(0x4f, IDE_LCYL_REG);
+ 			hwif->OUTB(0xc2, IDE_HCYL_REG);
+ 			hwif->OUTB(args[2],IDE_FEATURE_REG);
+ 			hwif->OUTB(args[1],IDE_SECTOR_REG);
+ 			ide_cmd(drive, args[0], args[3], &drive_cmd_intr);
+ 			return ide_started;
+ 		}
+ 		hwif->OUTB(args[2],IDE_FEATURE_REG);
+ 		ide_cmd(drive, args[0], args[1], &drive_cmd_intr);
+ 		return ide_started;
+ 	}
+
+done:
+ 	/*
+ 	 * 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->INB(IDE_STATUS_REG),
+			hwif->INB(IDE_ERROR_REG));
+ 	return ide_stopped;
+}
+
+/**
+ *	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. It also does
+ *	the final remapping for weird stuff like EZDrive. Once 
+ *	device mapper can work sector level the EZDrive stuff can go away
+ *
+ *	FIXME: this function needs a rename
+ */
+ 
+static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
+{
+	ide_startstop_t startstop;
+	sector_t block;
+
+	BUG_ON(!(rq->flags & REQ_STARTED));
+
+#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)) {
+		goto kill_rq;
+	}
+
+	block    = rq->sector;
+	if (blk_fs_request(rq) &&
+	    (drive->media == ide_disk || drive->media == ide_floppy)) {
+		block += drive->sect0;
+	}
+	/* Yecch - this will shift the entire interval,
+	   possibly killing some innocent following sector */
+	if (block == 0 && drive->remap_0_to_1 == 1)
+		block = 1;  /* redirect MBR access to EZ-Drive partn table */
+
+	if (blk_pm_suspend_request(rq) &&
+	    rq->pm->pm_step == ide_pm_state_start_suspend)
+		/* Mark drive blocked when starting the suspend sequence. */
+		drive->blocked = 1;
+	else if (blk_pm_resume_request(rq) &&
+		 rq->pm->pm_step == ide_pm_state_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.
+		 */
+		int rc;
+#ifdef DEBUG_PM
+		printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
+#endif
+		rc = ide_wait_not_busy(HWIF(drive), 35000);
+		if (rc)
+			printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
+		SELECT_DRIVE(drive);
+		HWIF(drive)->OUTB(8, HWIF(drive)->io_ports[IDE_CONTROL_OFFSET]);
+		rc = ide_wait_not_busy(HWIF(drive), 10000);
+		if (rc)
+			printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
+	}
+
+	SELECT_DRIVE(drive);
+	if (ide_wait_stat(&startstop, drive, drive->ready_stat, BUSY_STAT|DRQ_STAT, WAIT_READY)) {
+		printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
+		return startstop;
+	}
+	if (!drive->special.all) {
+		ide_driver_t *drv;
+
+		if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK))
+			return execute_drive_cmd(drive, rq);
+		else if (rq->flags & REQ_DRIVE_TASKFILE)
+			return execute_drive_cmd(drive, rq);
+		else if (blk_pm_request(rq)) {
+#ifdef DEBUG_PM
+			printk("%s: start_power_step(step: %d)\n",
+				drive->name, rq->pm->pm_step);
+#endif
+			startstop = ide_start_power_step(drive, rq);
+			if (startstop == ide_stopped &&
+			    rq->pm->pm_step == ide_pm_state_completed)
+				ide_complete_pm_request(drive, rq);
+			return startstop;
+		}
+
+		drv = *(ide_driver_t **)rq->rq_disk->private_data;
+		return drv->do_request(drive, rq, block);
+	}
+	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->sleeping = 1;
+}
+
+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 {
+		if ((!drive->sleeping || time_after_eq(jiffies, drive->sleep))
+		    && !elv_queue_empty(drive->queue)) {
+			if (!best
+			 || (drive->sleeping && (!best->sleeping || time_before(drive->sleep, best->sleep)))
+			 || (!best->sleeping && time_before(WAKEUP(drive), WAKEUP(best))))
+			{
+				if (!blk_queue_plugged(drive->queue))
+					best = drive;
+			}
+		}
+	} while ((drive = drive->next) != hwgroup->drive);
+	if (best && best->nice1 && !best->sleeping && 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->sleeping
+				 && 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.
+ *