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, 1593 insertions, 0 deletions

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
new file mode 100644
index 00000000000..4e5e54a1564
--- /dev/null
+++ b/drivers/scsi/libata-scsi.c
@@ -0,0 +1,1593 @@
+/*
+   libata-scsi.c - helper library for ATA
+
+   Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
+   Copyright 2003-2004 Jeff Garzik
+
+   The contents of this file are subject to the Open
+   Software License version 1.1 that can be found at
+   http://www.opensource.org/licenses/osl-1.1.txt and is included herein
+   by reference.
+
+   Alternatively, the contents of this file may be used under the terms
+   of the GNU General Public License version 2 (the "GPL") as distributed
+   in the kernel source COPYING file, in which case the provisions of
+   the GPL are applicable instead of the above.  If you wish to allow
+   the use of your version of this file only under the terms of the
+   GPL and not to allow others to use your version of this file under
+   the OSL, indicate your decision by deleting the provisions above and
+   replace them with the notice and other provisions required by the GPL.
+   If you do not delete the provisions above, a recipient may use your
+   version of this file under either the OSL or the GPL.
+
+ */
+
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/spinlock.h>
+#include <scsi/scsi.h>
+#include "scsi.h"
+#include <scsi/scsi_host.h>
+#include <linux/libata.h>
+#include <asm/uaccess.h>
+
+#include "libata.h"
+
+typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, u8 *scsicmd);
+static struct ata_device *
+ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev);
+
+
+/**
+ *	ata_std_bios_param - generic bios head/sector/cylinder calculator used by sd.
+ *	@sdev: SCSI device for which BIOS geometry is to be determined
+ *	@bdev: block device associated with @sdev
+ *	@capacity: capacity of SCSI device
+ *	@geom: location to which geometry will be output
+ *
+ *	Generic bios head/sector/cylinder calculator
+ *	used by sd. Most BIOSes nowadays expect a XXX/255/16  (CHS)
+ *	mapping. Some situations may arise where the disk is not
+ *	bootable if this is not used.
+ *
+ *	LOCKING:
+ *	Defined by the SCSI layer.  We don't really care.
+ *
+ *	RETURNS:
+ *	Zero.
+ */
+int ata_std_bios_param(struct scsi_device *sdev, struct block_device *bdev,
+		       sector_t capacity, int geom[])
+{
+	geom[0] = 255;
+	geom[1] = 63;
+	sector_div(capacity, 255*63);
+	geom[2] = capacity;
+
+	return 0;
+}
+
+int ata_scsi_ioctl(struct scsi_device *scsidev, int cmd, void __user *arg)
+{
+	struct ata_port *ap;
+	struct ata_device *dev;
+	int val = -EINVAL, rc = -EINVAL;
+
+	ap = (struct ata_port *) &scsidev->host->hostdata[0];
+	if (!ap)
+		goto out;
+
+	dev = ata_scsi_find_dev(ap, scsidev);
+	if (!dev) {
+		rc = -ENODEV;
+		goto out;
+	}
+
+	switch (cmd) {
+	case ATA_IOC_GET_IO32:
+		val = 0;
+		if (copy_to_user(arg, &val, 1))
+			return -EFAULT;
+		return 0;
+
+	case ATA_IOC_SET_IO32:
+		val = (unsigned long) arg;
+		if (val != 0)
+			return -EINVAL;
+		return 0;
+
+	default:
+		rc = -ENOTTY;
+		break;
+	}
+
+out:
+	return rc;
+}
+
+/**
+ *	ata_scsi_qc_new - acquire new ata_queued_cmd reference
+ *	@ap: ATA port to which the new command is attached
+ *	@dev: ATA device to which the new command is attached
+ *	@cmd: SCSI command that originated this ATA command
+ *	@done: SCSI command completion function
+ *
+ *	Obtain a reference to an unused ata_queued_cmd structure,
+ *	which is the basic libata structure representing a single
+ *	ATA command sent to the hardware.
+ *
+ *	If a command was available, fill in the SCSI-specific
+ *	portions of the structure with information on the
+ *	current command.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Command allocated, or %NULL if none available.
+ */
+struct ata_queued_cmd *ata_scsi_qc_new(struct ata_port *ap,
+				       struct ata_device *dev,
+				       struct scsi_cmnd *cmd,
+				       void (*done)(struct scsi_cmnd *))
+{
+	struct ata_queued_cmd *qc;
+
+	qc = ata_qc_new_init(ap, dev);
+	if (qc) {
+		qc->scsicmd = cmd;
+		qc->scsidone = done;
+
+		if (cmd->use_sg) {
+			qc->sg = (struct scatterlist *) cmd->request_buffer;
+			qc->n_elem = cmd->use_sg;
+		} else {
+			qc->sg = &qc->sgent;
+			qc->n_elem = 1;
+		}
+	} else {
+		cmd->result = (DID_OK << 16) | (QUEUE_FULL << 1);
+		done(cmd);
+	}
+
+	return qc;
+}
+
+/**
+ *	ata_to_sense_error - convert ATA error to SCSI error
+ *	@qc: Command that we are erroring out
+ *	@drv_stat: value contained in ATA status register
+ *
+ *	Converts an ATA error into a SCSI error. While we are at it
+ *	we decode and dump the ATA error for the user so that they
+ *	have some idea what really happened at the non make-believe
+ *	layer.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+void ata_to_sense_error(struct ata_queued_cmd *qc, u8 drv_stat)
+{
+	struct scsi_cmnd *cmd = qc->scsicmd;
+	u8 err = 0;
+	unsigned char *sb = cmd->sense_buffer;
+	/* Based on the 3ware driver translation table */
+	static unsigned char sense_table[][4] = {
+		/* BBD|ECC|ID|MAR */
+		{0xd1, 		ABORTED_COMMAND, 0x00, 0x00}, 	// Device busy                  Aborted command
+		/* BBD|ECC|ID */
+		{0xd0,  	ABORTED_COMMAND, 0x00, 0x00}, 	// Device busy                  Aborted command
+		/* ECC|MC|MARK */
+		{0x61, 		HARDWARE_ERROR, 0x00, 0x00}, 	// Device fault                 Hardware error
+		/* ICRC|ABRT */		/* NB: ICRC & !ABRT is BBD */
+		{0x84, 		ABORTED_COMMAND, 0x47, 0x00}, 	// Data CRC error               SCSI parity error
+		/* MC|ID|ABRT|TRK0|MARK */
+		{0x37, 		NOT_READY, 0x04, 0x00}, 	// Unit offline                 Not ready
+		/* MCR|MARK */
+		{0x09, 		NOT_READY, 0x04, 0x00}, 	// Unrecovered disk error       Not ready
+		/*  Bad address mark */
+		{0x01, 		MEDIUM_ERROR, 0x13, 0x00}, 	// Address mark not found       Address mark not found for data field
+		/* TRK0 */
+		{0x02, 		HARDWARE_ERROR, 0x00, 0x00}, 	// Track 0 not found		  Hardware error
+		/* Abort & !ICRC */
+		{0x04, 		ABORTED_COMMAND, 0x00, 0x00}, 	// Aborted command              Aborted command
+		/* Media change request */
+		{0x08, 		NOT_READY, 0x04, 0x00}, 	// Media change request	  FIXME: faking offline
+		/* SRV */
+		{0x10, 		ABORTED_COMMAND, 0x14, 0x00}, 	// ID not found                 Recorded entity not found
+		/* Media change */
+		{0x08,  	NOT_READY, 0x04, 0x00}, 	// Media change		  FIXME: faking offline
+		/* ECC */
+		{0x40, 		MEDIUM_ERROR, 0x11, 0x04}, 	// Uncorrectable ECC error      Unrecovered read error
+		/* BBD - block marked bad */
+		{0x80, 		MEDIUM_ERROR, 0x11, 0x04}, 	// Block marked bad		  Medium error, unrecovered read error
+		{0xFF, 0xFF, 0xFF, 0xFF}, // END mark
+	};
+	static unsigned char stat_table[][4] = {
+		/* Must be first because BUSY means no other bits valid */
+		{0x80, 		ABORTED_COMMAND, 0x47, 0x00},	// Busy, fake parity for now
+		{0x20, 		HARDWARE_ERROR,  0x00, 0x00}, 	// Device fault
+		{0x08, 		ABORTED_COMMAND, 0x47, 0x00},	// Timed out in xfer, fake parity for now
+		{0x04, 		RECOVERED_ERROR, 0x11, 0x00},	// Recovered ECC error	  Medium error, recovered
+		{0xFF, 0xFF, 0xFF, 0xFF}, // END mark
+	};
+	int i = 0;
+
+	cmd->result = SAM_STAT_CHECK_CONDITION;
+
+	/*
+	 *	Is this an error we can process/parse
+	 */
+
+	if(drv_stat & ATA_ERR)
+		/* Read the err bits */
+		err = ata_chk_err(qc->ap);
+
+	/* Display the ATA level error info */
+
+	printk(KERN_WARNING "ata%u: status=0x%02x { ", qc->ap->id, drv_stat);
+	if(drv_stat & 0x80)
+	{
+		printk("Busy ");
+		err = 0;	/* Data is not valid in this case */
+	}
+	else {
+		if(drv_stat & 0x40)	printk("DriveReady ");
+		if(drv_stat & 0x20)	printk("DeviceFault ");
+		if(drv_stat & 0x10)	printk("SeekComplete ");
+		if(drv_stat & 0x08)	printk("DataRequest ");
+		if(drv_stat & 0x04)	printk("CorrectedError ");
+		if(drv_stat & 0x02)	printk("Index ");
+		if(drv_stat & 0x01)	printk("Error ");
+	}
+	printk("}\n");
+
+	if(err)
+	{
+		printk(KERN_WARNING "ata%u: error=0x%02x { ", qc->ap->id, err);
+		if(err & 0x04)		printk("DriveStatusError ");
+		if(err & 0x80)
+		{
+			if(err & 0x04)
+				printk("BadCRC ");
+			else
+				printk("Sector ");
+		}
+		if(err & 0x40)		printk("UncorrectableError ");
+		if(err & 0x10)		printk("SectorIdNotFound ");
+		if(err & 0x02)		printk("TrackZeroNotFound ");
+		if(err & 0x01)		printk("AddrMarkNotFound ");
+		printk("}\n");
+
+		/* Should we dump sector info here too ?? */
+	}
+
+
+	/* Look for err */
+	while(sense_table[i][0] != 0xFF)
+	{
+		/* Look for best matches first */
+		if((sense_table[i][0] & err) == sense_table[i][0])
+		{
+			sb[0] = 0x70;
+			sb[2] = sense_table[i][1];
+			sb[7] = 0x0a;
+			sb[12] = sense_table[i][2];
+			sb[13] = sense_table[i][3];
+			return;
+		}
+		i++;
+	}
+	/* No immediate match */
+	if(err)
+		printk(KERN_DEBUG "ata%u: no sense translation for 0x%02x\n", qc->ap->id, err);
+
+	i = 0;
+	/* Fall back to interpreting status bits */
+	while(stat_table[i][0] != 0xFF)
+	{
+		if(stat_table[i][0] & drv_stat)
+		{
+			sb[0] = 0x70;
+			sb[2] = stat_table[i][1];
+			sb[7] = 0x0a;
+			sb[12] = stat_table[i][2];
+			sb[13] = stat_table[i][3];
+			return;
+		}
+		i++;
+	}
+	/* No error ?? */
+	printk(KERN_ERR "ata%u: called with no error (%02X)!\n", qc->ap->id, drv_stat);
+	/* additional-sense-code[-qualifier] */
+
+	sb[0] = 0x70;
+	sb[2] = MEDIUM_ERROR;
+	sb[7] = 0x0A;
+	if (cmd->sc_data_direction == SCSI_DATA_READ) {
+		sb[12] = 0x11; /* "unrecovered read error" */
+		sb[13] = 0x04;
+	} else {
+		sb[12] = 0x0C; /* "write error -             */
+		sb[13] = 0x02; /*  auto-reallocation failed" */
+	}
+}
+
+/**
+ *	ata_scsi_slave_config - Set SCSI device attributes
+ *	@sdev: SCSI device to examine
+ *
+ *	This is called before we actually start reading
+ *	and writing to the device, to configure certain
+ *	SCSI mid-layer behaviors.
+ *
+ *	LOCKING:
+ *	Defined by SCSI layer.  We don't really care.
+ */
+
+int ata_scsi_slave_config(struct scsi_device *sdev)
+{
+	sdev->use_10_for_rw = 1;
+	sdev->use_10_for_ms = 1;
+
+	blk_queue_max_phys_segments(sdev->request_queue, LIBATA_MAX_PRD);
+
+	if (sdev->id < ATA_MAX_DEVICES) {
+		struct ata_port *ap;
+		struct ata_device *dev;
+
+		ap = (struct ata_port *) &sdev->host->hostdata[0];
+		dev = &ap->device[sdev->id];
+
+		/* TODO: 1024 is an arbitrary number, not the
+		 * hardware maximum.  This should be increased to
+		 * 65534 when Jens Axboe's patch for dynamically
+		 * determining max_sectors is merged.
+		 */
+		if ((dev->flags & ATA_DFLAG_LBA48) &&
+		    ((dev->flags & ATA_DFLAG_LOCK_SECTORS) == 0)) {
+			sdev->host->max_sectors = 2048;
+			blk_queue_max_sectors(sdev->request_queue, 2048);
+		}
+	}
+
+	return 0;	/* scsi layer doesn't check return value, sigh */
+}
+
+/**
+ *	ata_scsi_error - SCSI layer error handler callback
+ *	@host: SCSI host on which error occurred
+ *
+ *	Handles SCSI-layer-thrown error events.
+ *
+ *	LOCKING:
+ *	Inherited from SCSI layer (none, can sleep)
+ *
+ *	RETURNS:
+ *	Zero.
+ */
+
+int ata_scsi_error(struct Scsi_Host *host)
+{
+	struct ata_port *ap;
+
+	DPRINTK("ENTER\n");
+
+	ap = (struct ata_port *) &host->hostdata[0];
+	ap->ops->eng_timeout(ap);
+
+	/* TODO: this is per-command; when queueing is supported
+	 * this code will either change or move to a more
+	 * appropriate place
+	 */
+	host->host_failed--;
+
+	DPRINTK("EXIT\n");
+	return 0;
+}
+
+/**
+ *	ata_scsi_flush_xlat - Translate SCSI SYNCHRONIZE CACHE command
+ *	@qc: Storage for translated ATA taskfile
+ *	@scsicmd: SCSI command to translate (ignored)
+ *
+ *	Sets up an ATA taskfile to issue FLUSH CACHE or
+ *	FLUSH CACHE EXT.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Zero on success, non-zero on error.
+ */
+
+static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
+{
+	struct ata_taskfile *tf = &qc->tf;
+
+	tf->flags |= ATA_TFLAG_DEVICE;
+	tf->protocol = ATA_PROT_NODATA;
+
+	if ((tf->flags & ATA_TFLAG_LBA48) &&
+	    (ata_id_has_flush_ext(qc->dev->id)))
+		tf->command = ATA_CMD_FLUSH_EXT;
+	else
+		tf->command = ATA_CMD_FLUSH;
+
+	return 0;
+}
+
+/**
+ *	ata_scsi_verify_xlat - Translate SCSI VERIFY command into an ATA one
+ *	@qc: Storage for translated ATA taskfile
+ *	@scsicmd: SCSI command to translate
+ *
+ *	Converts SCSI VERIFY command to an ATA READ VERIFY command.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Zero on success, non-zero on error.
+ */
+
+static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
+{
+	struct ata_taskfile *tf = &qc->tf;
+	unsigned int lba48 = tf->flags & ATA_TFLAG_LBA48;
+	u64 dev_sectors = qc->dev->n_sectors;
+	u64 sect = 0;
+	u32 n_sect = 0;
+
+	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf->protocol = ATA_PROT_NODATA;
+	tf->device |= ATA_LBA;
+
+	if (scsicmd[0] == VERIFY) {
+		sect |= ((u64)scsicmd[2]) << 24;
+		sect |= ((u64)scsicmd[3]) << 16;
+		sect |= ((u64)scsicmd[4]) << 8;
+		sect |= ((u64)scsicmd[5]);
+
+		n_sect |= ((u32)scsicmd[7]) << 8;
+		n_sect |= ((u32)scsicmd[8]);
+	}
+
+	else if (scsicmd[0] == VERIFY_16) {
+		sect |= ((u64)scsicmd[2]) << 56;
+		sect |= ((u64)scsicmd[3]) << 48;
+		sect |= ((u64)scsicmd[4]) << 40;
+		sect |= ((u64)scsicmd[5]) << 32;
+		sect |= ((u64)scsicmd[6]) << 24;
+		sect |= ((u64)scsicmd[7]) << 16;
+		sect |= ((u64)scsicmd[8]) << 8;
+		sect |= ((u64)scsicmd[9]);
+
+		n_sect |= ((u32)scsicmd[10]) << 24;
+		n_sect |= ((u32)scsicmd[11]) << 16;
+		n_sect |= ((u32)scsicmd[12]) << 8;
+		n_sect |= ((u32)scsicmd[13]);
+	}
+
+	else
+		return 1;
+
+	if (!n_sect)
+		return 1;
+	if (sect >= dev_sectors)
+		return 1;
+	if ((sect + n_sect) > dev_sectors)
+		return 1;
+	if (lba48) {
+		if (n_sect > (64 * 1024))
+			return 1;
+	} else {
+		if (n_sect > 256)
+			return 1;
+	}
+
+	if (lba48) {
+		tf->command = ATA_CMD_VERIFY_EXT;
+
+		tf->hob_nsect = (n_sect >> 8) & 0xff;
+
+		tf->hob_lbah = (sect >> 40) & 0xff;
+		tf->hob_lbam = (sect >> 32) & 0xff;
+		tf->hob_lbal = (sect >> 24) & 0xff;
+	} else {
+		tf->command = ATA_CMD_VERIFY;
+
+		tf->device |= (sect >> 24) & 0xf;
+	}
+
+	tf->nsect = n_sect & 0xff;
+
+	tf->lbah = (sect >> 16) & 0xff;
+	tf->lbam = (sect >> 8) & 0xff;
+	tf->lbal = sect & 0xff;
+
+	return 0;
+}
+
+/**
+ *	ata_scsi_rw_xlat - Translate SCSI r/w command into an ATA one
+ *	@qc: Storage for translated ATA taskfile
+ *	@scsicmd: SCSI command to translate
+ *
+ *	Converts any of six SCSI read/write commands into the
+ *	ATA counterpart, including starting sector (LBA),
+ *	sector count, and taking into account the device's LBA48
+ *	support.
+ *
+ *	Commands %READ_6, %READ_10, %READ_16, %WRITE_6, %WRITE_10, and
+ *	%WRITE_16 are currently supported.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Zero on success, non-zero on error.
+ */
+
+static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
+{
+	struct ata_taskfile *tf = &qc->tf;
+	unsigned int lba48 = tf->flags & ATA_TFLAG_LBA48;
+
+	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf->protocol = qc->dev->xfer_protocol;
+	tf->device |= ATA_LBA;
+
+	if (scsicmd[0] == READ_10 || scsicmd[0] == READ_6 ||
+	    scsicmd[0] == READ_16) {
+		tf->command = qc->dev->read_cmd;
+	} else {
+		tf->command = qc->dev->write_cmd;
+		tf->flags |= ATA_TFLAG_WRITE;
+	}
+
+	if (scsicmd[0] == READ_10 || scsicmd[0] == WRITE_10) {
+		if (lba48) {
+			tf->hob_nsect = scsicmd[7];
+			tf->hob_lbal = scsicmd[2];
+
+			qc->nsect = ((unsigned int)scsicmd[7] << 8) |
+					scsicmd[8];
+		} else {
+			/* if we don't support LBA48 addressing, the request
+			 * -may- be too large. */
+			if ((scsicmd[2] & 0xf0) || scsicmd[7])
+				return 1;
+
+			/* stores LBA27:24 in lower 4 bits of device reg */
+			tf->device |= scsicmd[2];
+
+			qc->nsect = scsicmd[8];
+		}
+
+		tf->nsect = scsicmd[8];
+		tf->lbal = scsicmd[5];
+		tf->lbam = scsicmd[4];
+		tf->lbah = scsicmd[3];
+
+		VPRINTK("ten-byte command\n");
+		return 0;
+	}
+
+	if (scsicmd[0] == READ_6 || scsicmd[0] == WRITE_6) {
+		qc->nsect = tf->nsect = scsicmd[4];
+		tf->lbal = scsicmd[3];
+		tf->lbam = scsicmd[2];
+		tf->lbah = scsicmd[1] & 0x1f; /* mask out reserved bits */
+
+		VPRINTK("six-byte command\n");
+		return 0;
+	}
+
+	if (scsicmd[0] == READ_16 || scsicmd[0] == WRITE_16) {
+		/* rule out impossible LBAs and sector counts */
+		if (scsicmd[2] || scsicmd[3] || scsicmd[10] || scsicmd[11])
+			return 1;
+
+		if (lba48) {
+			tf->hob_nsect = scsicmd[12];
+			tf->hob_lbal = scsicmd[6];
+			tf->hob_lbam = scsicmd[5];
+			tf->hob_lbah = scsicmd[4];
+
+			qc->nsect = ((unsigned int)scsicmd[12] << 8) |
+					scsicmd[13];
+		} else {
+			/* once again, filter out impossible non-zero values */
+			if (scsicmd[4] || scsicmd[5] || scsicmd[12] ||
+			    (scsicmd[6] & 0xf0))
+				return 1;
+
+			/* stores LBA27:24 in lower 4 bits of device reg */
+			tf->device |= scsicmd[6];
+
+			qc->nsect = scsicmd[13];
+		}
+
+		tf->nsect = scsicmd[13];
+		tf->lbal = scsicmd[9];
+		tf->lbam = scsicmd[8];
+		tf->lbah = scsicmd[7];
+
+		VPRINTK("sixteen-byte command\n");
+		return 0;
+	}
+
+	DPRINTK("no-byte command\n");
+	return 1;
+}
+
+static int ata_scsi_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
+{
+	struct scsi_cmnd *cmd = qc->scsicmd;
+
+	if (unlikely(drv_stat & (ATA_ERR | ATA_BUSY | ATA_DRQ)))
+		ata_to_sense_error(qc, drv_stat);
+	else
+		cmd->result = SAM_STAT_GOOD;
+
+	qc->scsidone(cmd);
+
+	return 0;
+}
+
+/**
+ *	ata_scsi_translate - Translate then issue SCSI command to ATA device
+ *	@ap: ATA port to which the command is addressed
+ *	@dev: ATA device to which the command is addressed
+ *	@cmd: SCSI command to execute
+ *	@done: SCSI command completion function
+ *	@xlat_func: Actor which translates @cmd to an ATA taskfile
+ *
+ *	Our ->queuecommand() function has decided that the SCSI
+ *	command issued can be directly translated into an ATA
+ *	command, rather than handled internally.
+ *
+ *	This function sets up an ata_queued_cmd structure for the
+ *	SCSI command, and sends that ata_queued_cmd to the hardware.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+static void ata_scsi_translate(struct ata_port *ap, struct ata_device *dev,
+			      struct scsi_cmnd *cmd,
+			      void (*done)(struct scsi_cmnd *),
+			      ata_xlat_func_t xlat_func)
+{
+	struct ata_queued_cmd *qc;
+	u8 *scsicmd = cmd->cmnd;
+
+	VPRINTK("ENTER\n");
+
+	qc = ata_scsi_qc_new(ap, dev, cmd, done);
+	if (!qc)
+		return;
+
+	/* data is present; dma-map it */
+	if (cmd->sc_data_direction == SCSI_DATA_READ ||
+	    cmd->sc_data_direction == SCSI_DATA_WRITE) {
+		if (unlikely(cmd->request_bufflen < 1)) {
+			printk(KERN_WARNING "ata%u(%u): WARNING: zero len r/w req\n",
+			       ap->id, dev->devno);
+			goto err_out;
+		}
+
+		if (cmd->use_sg)
+			ata_sg_init(qc, cmd->request_buffer, cmd->use_sg);
+		else
+			ata_sg_init_one(qc, cmd->request_buffer,
+					cmd->request_bufflen);
+
+		qc->dma_dir = cmd->sc_data_direction;
+	}
+
+	qc->complete_fn = ata_scsi_qc_complete;
+
+	if (xlat_func(qc, scsicmd))
+		goto err_out;
+
+	/* select device, send command to hardware */
+	if (ata_qc_issue(qc))
+		goto err_out;
+
+	VPRINTK("EXIT\n");
+	return;
+
+err_out:
+	ata_qc_free(qc);
+	ata_bad_cdb(cmd, done);
+	DPRINTK("EXIT - badcmd\n");
+}
+
+/**
+ *	ata_scsi_rbuf_get - Map response buffer.
+ *	@cmd: SCSI command containing buffer to be mapped.
+ *	@buf_out: Pointer to mapped area.
+ *
+ *	Maps buffer contained within SCSI command @cmd.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Length of response buffer.
+ */
+
+static unsigned int ata_scsi_rbuf_get(struct scsi_cmnd *cmd, u8 **buf_out)
+{
+	u8 *buf;
+	unsigned int buflen;
+
+	if (cmd->use_sg) {
+		struct scatterlist *sg;
+
+		sg = (struct scatterlist *) cmd->request_buffer;
+		buf = kmap_atomic(sg->page, KM_USER0) + sg->offset;
+		buflen = sg->length;
+	} else {
+		buf = cmd->request_buffer;
+		buflen = cmd->request_bufflen;
+	}
+
+	*buf_out = buf;
+	return buflen;
+}
+
+/**
+ *	ata_scsi_rbuf_put - Unmap response buffer.
+ *	@cmd: SCSI command containing buffer to be unmapped.
+ *	@buf: buffer to unmap
+ *
+ *	Unmaps response buffer contained within @cmd.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, u8 *buf)
+{
+	if (cmd->use_sg) {
+		struct scatterlist *sg;
+
+		sg = (struct scatterlist *) cmd->request_buffer;
+		kunmap_atomic(buf - sg->offset, KM_USER0);
+	}
+}
+
+/**
+ *	ata_scsi_rbuf_fill - wrapper for SCSI command simulators
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@actor: Callback hook for desired SCSI command simulator
+ *
+ *	Takes care of the hard work of simulating a SCSI command...
+ *	Mapping the response buffer, calling the command's handler,
+ *	and handling the handler's return value.  This return value
+ *	indicates whether the handler wishes the SCSI command to be
+ *	completed successfully, or not.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
+		        unsigned int (*actor) (struct ata_scsi_args *args,
+			     		   u8 *rbuf, unsigned int buflen))
+{
+	u8 *rbuf;
+	unsigned int buflen, rc;
+	struct scsi_cmnd *cmd = args->cmd;
+
+	buflen = ata_scsi_rbuf_get(cmd, &rbuf);
+	memset(rbuf, 0, buflen);
+	rc = actor(args, rbuf, buflen);
+	ata_scsi_rbuf_put(cmd, rbuf);
+
+	if (rc)
+		ata_bad_cdb(cmd, args->done);
+	else {
+		cmd->result = SAM_STAT_GOOD;
+		args->done(cmd);
+	}
+}
+
+/**
+ *	ata_scsiop_inq_std - Simulate INQUIRY command
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Returns standard device identification data associated
+ *	with non-EVPD INQUIRY command output.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
+			       unsigned int buflen)
+{
+	u8 hdr[] = {
+		TYPE_DISK,
+		0,
+		0x5,	/* claim SPC-3 version compatibility */
+		2,
+		95 - 4
+	};
+
+	/* set scsi removeable (RMB) bit per ata bit */
+	if (ata_id_removeable(args->id))
+		hdr[1] |= (1 << 7);
+
+	VPRINTK("ENTER\n");
+
+	memcpy(rbuf, hdr, sizeof(hdr));
+
+	if (buflen > 35) {
+		memcpy(&rbuf[8], "ATA     ", 8);
+		ata_dev_id_string(args->id, &rbuf[16], ATA_ID_PROD_OFS, 16);
+		ata_dev_id_string(args->id, &rbuf[32], ATA_ID_FW_REV_OFS, 4);
+		if (rbuf[32] == 0 || rbuf[32] == ' ')
+			memcpy(&rbuf[32], "n/a ", 4);
+	}
+
+	if (buflen > 63) {
+		const u8 versions[] = {
+			0x60,	/* SAM-3 (no version claimed) */
+
+			0x03,
+			0x20,	/* SBC-2 (no version claimed) */
+
+			0x02,
+			0x60	/* SPC-3 (no version claimed) */
+		};
+
+		memcpy(rbuf + 59, versions, sizeof(versions));
+	}
+
+	return 0;
+}
+
+/**
+ *	ata_scsiop_inq_00 - Simulate INQUIRY EVPD page 0, list of pages
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Returns list of inquiry EVPD pages available.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_inq_00(struct ata_scsi_args *args, u8 *rbuf,
+			      unsigned int buflen)
+{
+	const u8 pages[] = {
+		0x00,	/* page 0x00, this page */
+		0x80,	/* page 0x80, unit serial no page */
+		0x83	/* page 0x83, device ident page */
+	};
+	rbuf[3] = sizeof(pages);	/* number of supported EVPD pages */
+
+	if (buflen > 6)
+		memcpy(rbuf + 4, pages, sizeof(pages));
+
+	return 0;
+}
+
+/**
+ *	ata_scsiop_inq_80 - Simulate INQUIRY EVPD page 80, device serial number
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Returns ATA device serial number.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_inq_80(struct ata_scsi_args *args, u8 *rbuf,
+			      unsigned int buflen)
+{
+	const u8 hdr[] = {
+		0,
+		0x80,			/* this page code */
+		0,
+		ATA_SERNO_LEN,		/* page len */
+	};
+	memcpy(rbuf, hdr, sizeof(hdr));
+
+	if (buflen > (ATA_SERNO_LEN + 4 - 1))
+		ata_dev_id_string(args->id, (unsigned char *) &rbuf[4],
+				  ATA_ID_SERNO_OFS, ATA_SERNO_LEN);
+
+	return 0;
+}
+
+static const char *inq_83_str = "Linux ATA-SCSI simulator";
+
+/**
+ *	ata_scsiop_inq_83 - Simulate INQUIRY EVPD page 83, device identity
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Returns device identification.  Currently hardcoded to
+ *	return "Linux ATA-SCSI simulator".
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf,
+			      unsigned int buflen)
+{
+	rbuf[1] = 0x83;			/* this page code */
+	rbuf[3] = 4 + strlen(inq_83_str);	/* page len */
+
+	/* our one and only identification descriptor (vendor-specific) */
+	if (buflen > (strlen(inq_83_str) + 4 + 4 - 1)) {
+		rbuf[4 + 0] = 2;	/* code set: ASCII */
+		rbuf[4 + 3] = strlen(inq_83_str);
+		memcpy(rbuf + 4 + 4, inq_83_str, strlen(inq_83_str));
+	}
+
+	return 0;
+}
+
+/**
+ *	ata_scsiop_noop -
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	No operation.  Simply returns success to caller, to indicate
+ *	that the caller should successfully complete this SCSI command.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_noop(struct ata_scsi_args *args, u8 *rbuf,
+			    unsigned int buflen)
+{
+	VPRINTK("ENTER\n");
+	return 0;
+}
+
+/**
+ *	ata_msense_push - Push data onto MODE SENSE data output buffer
+ *	@ptr_io: (input/output) Location to store more output data
+ *	@last: End of output data buffer
+ *	@buf: Pointer to BLOB being added to output buffer
+ *	@buflen: Length of BLOB
+ *
+ *	Store MODE SENSE data on an output buffer.
+ *
+ *	LOCKING:
+ *	None.
+ */
+
+static void ata_msense_push(u8 **ptr_io, const u8 *last,
+			    const u8 *buf, unsigned int buflen)
+{
+	u8 *ptr = *ptr_io;
+
+	if ((ptr + buflen - 1) > last)
+		return;
+
+	memcpy(ptr, buf, buflen);
+
+	ptr += buflen;
+
+	*ptr_io = ptr;
+}
+
+/**
+ *	ata_msense_caching - Simulate MODE SENSE caching info page
+ *	@id: device IDENTIFY data
+ *	@ptr_io: (input/output) Location to store more output data
+ *	@last: End of output data buffer
+ *
+ *	Generate a caching info page, which conditionally indicates
+ *	write caching to the SCSI layer, depending on device
+ *	capabilities.
+ *
+ *	LOCKING:
+ *	None.
+ */
+
+static unsigned int ata_msense_caching(u16 *id, u8 **ptr_io,
+				       const u8 *last)
+{
+	u8 page[] = {
+		0x8,				/* page code */
+		0x12,				/* page length */
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 10 zeroes */
+		0, 0, 0, 0, 0, 0, 0, 0		/* 8 zeroes */
+	};
+
+	if (ata_id_wcache_enabled(id))
+		page[2] |= (1 << 2);	/* write cache enable */
+	if (!ata_id_rahead_enabled(id))
+		page[12] |= (1 << 5);	/* disable read ahead */
+
+	ata_msense_push(ptr_io, last, page, sizeof(page));
+	return sizeof(page);
+}
+
+/**
+ *	ata_msense_ctl_mode - Simulate MODE SENSE control mode page
+ *	@dev: Device associated with this MODE SENSE command
+ *	@ptr_io: (input/output) Location to store more output data
+ *	@last: End of output data buffer
+ *
+ *	Generate a generic MODE SENSE control mode page.
+ *
+ *	LOCKING:
+ *	None.
+ */
+
+static unsigned int ata_msense_ctl_mode(u8 **ptr_io, const u8 *last)
+{
+	const u8 page[] = {0xa, 0xa, 6, 0, 0, 0, 0, 0, 0xff, 0xff, 0, 30};
+
+	/* byte 2: set the descriptor format sense data bit (bit 2)
+	 * since we need to support returning this format for SAT
+	 * commands and any SCSI commands against a 48b LBA device.
+	 */
+
+	ata_msense_push(ptr_io, last, page, sizeof(page));
+	return sizeof(page);
+}
+
+/**
+ *	ata_msense_rw_recovery - Simulate MODE SENSE r/w error recovery page
+ *	@dev: Device associated with this MODE SENSE command
+ *	@ptr_io: (input/output) Location to store more output data
+ *	@last: End of output data buffer
+ *
+ *	Generate a generic MODE SENSE r/w error recovery page.
+ *
+ *	LOCKING:
+ *	None.
+ */
+
+static unsigned int ata_msense_rw_recovery(u8 **ptr_io, const u8 *last)
+{
+	const u8 page[] = {
+		0x1,			  /* page code */
+		0xa,			  /* page length */
+		(1 << 7) | (1 << 6),	  /* note auto r/w reallocation */
+		0, 0, 0, 0, 0, 0, 0, 0, 0 /* 9 zeroes */
+	};
+
+	ata_msense_push(ptr_io, last, page, sizeof(page));
+	return sizeof(page);
+}
+
+/**
+ *	ata_scsiop_mode_sense - Simulate MODE SENSE 6, 10 commands
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Simulate MODE SENSE commands.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf,
+				  unsigned int buflen)
+{
+	u8 *scsicmd = args->cmd->cmnd, *p, *last;
+	unsigned int page_control, six_byte, output_len;
+
+	VPRINTK("ENTER\n");
+
+	six_byte = (scsicmd[0] == MODE_SENSE);
+
+	/* we only support saved and current values (which we treat
+	 * in the same manner)
+	 */
+	page_control = scsicmd[2] >> 6;
+	if ((page_control != 0) && (page_control != 3))
+		return 1;
+
+	if (six_byte)
+		output_len = 4;
+	else
+		output_len = 8;
+
+	p = rbuf + output_len;
+	last = rbuf + buflen - 1;
+
+	switch(scsicmd[2] & 0x3f) {
+	case 0x01:		/* r/w error recovery */
+		output_len += ata_msense_rw_recovery(&p, last);
+		break;
+
+	case 0x08:		/* caching */
+		output_len += ata_msense_caching(args->id, &p, last);
+		break;
+
+	case 0x0a: {		/* control mode */
+		output_len += ata_msense_ctl_mode(&p, last);
+		break;
+		}
+
+	case 0x3f:		/* all pages */
+		output_len += ata_msense_rw_recovery(&p, last);
+		output_len += ata_msense_caching(args->id, &p, last);
+		output_len += ata_msense_ctl_mode(&p, last);
+		break;
+
+	default:		/* invalid page code */
+		return 1;
+	}
+
+	if (six_byte) {
+		output_len--;
+		rbuf[0] = output_len;
+	} else {
+		output_len -= 2;
+		rbuf[0] = output_len >> 8;
+		rbuf[1] = output_len;
+	}
+
+	return 0;
+}
+
+/**
+ *	ata_scsiop_read_cap - Simulate READ CAPACITY[ 16] commands
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Simulate READ CAPACITY commands.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf,
+			        unsigned int buflen)
+{
+	u64 n_sectors;
+	u32 tmp;
+
+	VPRINTK("ENTER\n");
+
+	if (ata_id_has_lba48(args->id))
+		n_sectors = ata_id_u64(args->id, 100);
+	else
+		n_sectors = ata_id_u32(args->id, 60);
+	n_sectors--;		/* ATA TotalUserSectors - 1 */
+
+	tmp = n_sectors;	/* note: truncates, if lba48 */
+	if (args->cmd->cmnd[0] == READ_CAPACITY) {
+		/* sector count, 32-bit */
+		rbuf[0] = tmp >> (8 * 3);
+		rbuf[1] = tmp >> (8 * 2);
+		rbuf[2] = tmp >> (8 * 1);
+		rbuf[3] = tmp;
+
+		/* sector size */
+		tmp = ATA_SECT_SIZE;
+		rbuf[6] = tmp >> 8;
+		rbuf[7] = tmp;
+
+	} else {
+		/* sector count, 64-bit */
+		rbuf[2] = n_sectors >> (8 * 7);
+		rbuf[3] = n_sectors >> (8 * 6);
+		rbuf[4] = n_sectors >> (8 * 5);
+		rbuf[5] = n_sectors >> (8 * 4);
+		rbuf[6] = tmp >> (8 * 3);
+		rbuf[7] = tmp >> (8 * 2);
+		rbuf[8] = tmp >> (8 * 1);
+		rbuf[9] = tmp;
+
+		/* sector size */
+		tmp = ATA_SECT_SIZE;
+		rbuf[12] = tmp >> 8;
+		rbuf[13] = tmp;
+	}
+
+	return 0;
+}
+
+/**
+ *	ata_scsiop_report_luns - Simulate REPORT LUNS command
+ *	@args: device IDENTIFY data / SCSI command of interest.
+ *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
+ *	@buflen: Response buffer length.
+ *
+ *	Simulate REPORT LUNS command.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+unsigned int ata_scsiop_report_luns(struct ata_scsi_args *args, u8 *rbuf,
+				   unsigned int buflen)
+{
+	VPRINTK("ENTER\n");
+	rbuf[3] = 8;	/* just one lun, LUN 0, size 8 bytes */
+
+	return 0;
+}
+
+/**
+ *	ata_scsi_badcmd - End a SCSI request with an error
+ *	@cmd: SCSI request to be handled
+ *	@done: SCSI command completion function
+ *	@asc: SCSI-defined additional sense code
+ *	@ascq: SCSI-defined additional sense code qualifier
+ *
+ *	Helper function that completes a SCSI command with
+ *	%SAM_STAT_CHECK_CONDITION, with a sense key %ILLEGAL_REQUEST
+ *	and the specified additional sense codes.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+void ata_scsi_badcmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *), u8 asc, u8 ascq)
+{
+	DPRINTK("ENTER\n");
+	cmd->result = SAM_STAT_CHECK_CONDITION;
+
+	cmd->sense_buffer[0] = 0x70;
+	cmd->sense_buffer[2] = ILLEGAL_REQUEST;
+	cmd->sense_buffer[7] = 14 - 8;	/* addnl. sense len. FIXME: correct? */
+	cmd->sense_buffer[12] = asc;
+	cmd->sense_buffer[13] = ascq;
+
+	done(cmd);
+}
+
+static int atapi_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
+{
+	struct scsi_cmnd *cmd = qc->scsicmd;
+
+	if (unlikely(drv_stat & (ATA_ERR | ATA_BUSY | ATA_DRQ))) {
+		DPRINTK("request check condition\n");
+
+		cmd->result = SAM_STAT_CHECK_CONDITION;
+
+		qc->scsidone(cmd);
+
+		return 1;
+	} else {
+		u8 *scsicmd = cmd->cmnd;
+
+		if (scsicmd[0] == INQUIRY) {
+			u8 *buf = NULL;
+			unsigned int buflen;
+
+			buflen = ata_scsi_rbuf_get(cmd, &buf);
+			buf[2] = 0x5;
+			buf[3] = (buf[3] & 0xf0) | 2;
+			ata_scsi_rbuf_put(cmd, buf);
+		}
+		cmd->result = SAM_STAT_GOOD;
+	}
+
+	qc->scsidone(cmd);
+
+	return 0;
+}
+/**
+ *	atapi_xlat - Initialize PACKET taskfile
+ *	@qc: command structure to be initialized
+ *	@scsicmd: SCSI CDB associated with this PACKET command
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Zero on success, non-zero on failure.
+ */
+
+static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
+{
+	struct scsi_cmnd *cmd = qc->scsicmd;
+	struct ata_device *dev = qc->dev;
+	int using_pio = (dev->flags & ATA_DFLAG_PIO);
+	int nodata = (cmd->sc_data_direction == SCSI_DATA_NONE);
+
+	if (!using_pio)
+		/* Check whether ATAPI DMA is safe */
+		if (ata_check_atapi_dma(qc))
+			using_pio = 1;
+
+	memcpy(&qc->cdb, scsicmd, qc->ap->cdb_len);
+
+	qc->complete_fn = atapi_qc_complete;
+
+	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	if (cmd->sc_data_direction == SCSI_DATA_WRITE) {
+		qc->tf.flags |= ATA_TFLAG_WRITE;
+		DPRINTK("direction: write\n");
+	}
+
+	qc->tf.command = ATA_CMD_PACKET;
+
+	/* no data, or PIO data xfer */
+	if (using_pio || nodata) {
+		if (nodata)
+			qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
+		else
+			qc->tf.protocol = ATA_PROT_ATAPI;
+		qc->tf.lbam = (8 * 1024) & 0xff;
+		qc->tf.lbah = (8 * 1024) >> 8;
+	}
+
+	/* DMA data xfer */
+	else {
+		qc->tf.protocol = ATA_PROT_ATAPI_DMA;
+		qc->tf.feature |= ATAPI_PKT_DMA;
+
+#ifdef ATAPI_ENABLE_DMADIR
+		/* some SATA bridges need us to indicate data xfer direction */
+		if (cmd->sc_data_direction != SCSI_DATA_WRITE)
+			qc->tf.feature |= ATAPI_DMADIR;
+#endif
+	}
+
+	qc->nbytes = cmd->bufflen;
+
+	return 0;
+}
+
+/**
+ *	ata_scsi_find_dev - lookup ata_device from scsi_cmnd
+ *	@ap: ATA port to which the device is attached
+ *	@scsidev: SCSI device from which we derive the ATA device
+ *
+ *	Given various information provided in struct scsi_cmnd,
+ *	map that onto an ATA bus, and using that mapping
+ *	determine which ata_device is associated with the
+ *	SCSI command to be sent.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	Associated ATA device, or %NULL if not found.
+ */
+
+static struct ata_device *
+ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev)
+{
+	struct ata_device *dev;
+
+	/* skip commands not addressed to targets we simulate */
+	if (likely(scsidev->id < ATA_MAX_DEVICES))
+		dev = &ap->device[scsidev->id];
+	else
+		return NULL;
+
+	if (unlikely((scsidev->channel != 0) ||
+		     (scsidev->lun != 0)))
+		return NULL;
+
+	if (unlikely(!ata_dev_present(dev)))
+		return NULL;
+
+#ifndef ATA_ENABLE_ATAPI
+	if (unlikely(dev->class == ATA_DEV_ATAPI))
+		return NULL;
+#endif
+
+	return dev;
+}
+
+/**
+ *	ata_get_xlat_func - check if SCSI to ATA translation is possible
+ *	@dev: ATA device
+ *	@cmd: SCSI command opcode to consider
+ *
+ *	Look up the SCSI command given, and determine whether the
+ *	SCSI command is to be translated or simulated.
+ *
+ *	RETURNS:
+ *	Pointer to translation function if possible, %NULL if not.
+ */
+
+static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
+{
+	switch (cmd) {
+	case READ_6:
+	case READ_10:
+	case READ_16:
+
+	case WRITE_6:
+	case WRITE_10:
+	case WRITE_16:
+		return ata_scsi_rw_xlat;
+
+	case SYNCHRONIZE_CACHE:
+		if (ata_try_flush_cache(dev))
+			return ata_scsi_flush_xlat;
+		break;
+
+	case VERIFY:
+	case VERIFY_16:
+		return ata_scsi_verify_xlat;
+	}
+
+	return NULL;
+}
+
+/**
+ *	ata_scsi_dump_cdb - dump SCSI command contents to dmesg
+ *	@ap: ATA port to which the command was being sent
+ *	@cmd: SCSI command to dump
+ *
+ *	Prints the contents of a SCSI command via printk().
+ */
+
+static inline void ata_scsi_dump_cdb(struct ata_port *ap,
+				     struct scsi_cmnd *cmd)
+{
+#ifdef ATA_DEBUG
+	struct scsi_device *scsidev = cmd->device;
+	u8 *scsicmd = cmd->cmnd;
+
+	DPRINTK("CDB (%u:%d,%d,%d) %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
+		ap->id,
+		scsidev->channel, scsidev->id, scsidev->lun,
+		scsicmd[0], scsicmd[1], scsicmd[2], scsicmd[3],
+		scsicmd[4], scsicmd[5], scsicmd[6], scsicmd[7],
+		scsicmd[8]);
+#endif
+}
+
+/**
+ *	ata_scsi_queuecmd - Issue SCSI cdb to libata-managed device
+ *	@cmd: SCSI command to be sent
+ *	@done: Completion function, called when command is complete
+ *
+ *	In some cases, this function translates SCSI commands into
+ *	ATA taskfiles, and queues the taskfiles to be sent to
+ *	hardware.  In other cases, this function simulates a
+ *	SCSI device by evaluating and responding to certain
+ *	SCSI commands.  This creates the overall effect of
+ *	ATA and ATAPI devices appearing as SCSI devices.
+ *
+ *	LOCKING:
+ *	Releases scsi-layer-held lock, and obtains host_set lock.
+ *
+ *	RETURNS:
+ *	Zero.
+ */
+
+int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
+{
+	struct ata_port *ap;
+	struct ata_device *dev;
+	struct scsi_device *scsidev = cmd->device;
+
+	ap = (struct ata_port *) &scsidev->host->hostdata[0];
+
+	ata_scsi_dump_cdb(ap, cmd);
+
+	dev = ata_scsi_find_dev(ap, scsidev);
+	if (unlikely(!dev)) {
+		cmd->result = (DID_BAD_TARGET << 16);
+		done(cmd);
+		goto out_unlock;
+	}
+
+	if (dev->class == ATA_DEV_ATA) {
+		ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
+							      cmd->cmnd[0]);
+
+		if (xlat_func)
+			ata_scsi_translate(ap, dev, cmd, done, xlat_func);
+		else
+			ata_scsi_simulate(dev->id, cmd, done);
+	} else
+		ata_scsi_translate(ap, dev, cmd, done, atapi_xlat);
+
+out_unlock:
+	return 0;
+}
+
+/**
+ *	ata_scsi_simulate - simulate SCSI command on ATA device
+ *	@id: current IDENTIFY data for target device.
+ *	@cmd: SCSI command being sent to device.
+ *	@done: SCSI command completion function.
+ *
+ *	Interprets and directly executes a select list of SCSI commands
+ *	that can be handled internally.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+
+void ata_scsi_simulate(u16 *id,
+		      struct scsi_cmnd *cmd,
+		      void (*done)(struct scsi_cmnd *))
+{
+	struct ata_scsi_args args;
+	u8 *scsicmd = cmd->cmnd;
+
+	args.id = id;
+	args.cmd = cmd;
+	args.done = done;
+
+	switch(scsicmd[0]) {
+		/* no-op's, complete with success */
+		case SYNCHRONIZE_CACHE:
+		case REZERO_UNIT:
+		case SEEK_6:
+		case SEEK_10:
+		case TEST_UNIT_READY:
+		case FORMAT_UNIT:		/* FIXME: correct? */
+		case SEND_DIAGNOSTIC:		/* FIXME: correct? */
+			ata_scsi_rbuf_fill(&args, ata_scsiop_noop);
+			break;
+
+		case INQUIRY:
+			if (scsicmd[1] & 2)	           /* is CmdDt set?  */
+				ata_bad_cdb(cmd, done);
+			else if ((scsicmd[1] & 1) == 0)    /* is EVPD clear? */
+				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_std);
+			else if (scsicmd[2] == 0x00)
+				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_00);
+			else if (scsicmd[2] == 0x80)
+				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_80);
+			else if (scsicmd[2] == 0x83)
+				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_83);
+			else
+				ata_bad_cdb(cmd, done);
+			break;
+
+		case MODE_SENSE:
+		case MODE_SENSE_10:
+			ata_scsi_rbuf_fill(&args, ata_scsiop_mode_sense);
+			break;
+
+		case MODE_SELECT:	/* unconditionally return */
+		case MODE_SELECT_10:	/* bad-field-in-cdb */
+			ata_bad_cdb(cmd, done);
+			break;
+
+		case READ_CAPACITY:
+			ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
+			break;
+
+		case SERVICE_ACTION_IN:
+			if ((scsicmd[1] & 0x1f) == SAI_READ_CAPACITY_16)
+				ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
+			else
+				ata_bad_cdb(cmd, done);
+			break;
+
+		case REPORT_LUNS:
+			ata_scsi_rbuf_fill(&args, ata_scsiop_report_luns);
+			break;
+
+		/* mandantory commands we haven't implemented yet */
+		case REQUEST_SENSE:
+
+		/* all other commands */
+		default:
+			ata_bad_scsiop(cmd, done);
+			break;
+	}
+}
+