/*
 *  libata-scsi.c - helper library for ATA
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *    		    Please ALWAYS copy linux-ide@vger.kernel.org
 *		    on emails.
 *
 *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
 *  Copyright 2003-2004 Jeff Garzik
 *
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from
 *  - http://www.t10.org/
 *  - http://www.t13.org/
 *
 */

#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/spinlock.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_transport.h>
#include <linux/libata.h>
#include <linux/hdreg.h>
#include <linux/uaccess.h>

#include "libata.h"

#define SECTOR_SIZE		512
#define ATA_SCSI_RBUF_SIZE	4096

static DEFINE_SPINLOCK(ata_scsi_rbuf_lock);
static u8 ata_scsi_rbuf[ATA_SCSI_RBUF_SIZE];

typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc);

static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
					const struct scsi_device *scsidev);
static struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
					    const struct scsi_device *scsidev);
static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
			      unsigned int id, unsigned int lun);


#define RW_RECOVERY_MPAGE 0x1
#define RW_RECOVERY_MPAGE_LEN 12
#define CACHE_MPAGE 0x8
#define CACHE_MPAGE_LEN 20
#define CONTROL_MPAGE 0xa
#define CONTROL_MPAGE_LEN 12
#define ALL_MPAGES 0x3f
#define ALL_SUB_MPAGES 0xff


static const u8 def_rw_recovery_mpage[RW_RECOVERY_MPAGE_LEN] = {
	RW_RECOVERY_MPAGE,
	RW_RECOVERY_MPAGE_LEN - 2,
	(1 << 7),	/* AWRE */
	0,		/* read retry count */
	0, 0, 0, 0,
	0,		/* write retry count */
	0, 0, 0
};

static const u8 def_cache_mpage[CACHE_MPAGE_LEN] = {
	CACHE_MPAGE,
	CACHE_MPAGE_LEN - 2,
	0,		/* contains WCE, needs to be 0 for logic */
	0, 0, 0, 0, 0, 0, 0, 0, 0,
	0,		/* contains DRA, needs to be 0 for logic */
	0, 0, 0, 0, 0, 0, 0
};

static const u8 def_control_mpage[CONTROL_MPAGE_LEN] = {
	CONTROL_MPAGE,
	CONTROL_MPAGE_LEN - 2,
	2,	/* DSENSE=0, GLTSD=1 */
	0,	/* [QAM+QERR may be 1, see 05-359r1] */
	0, 0, 0, 0, 0xff, 0xff,
	0, 30	/* extended self test time, see 05-359r1 */
};

/*
 * libata transport template.  libata doesn't do real transport stuff.
 * It just needs the eh_timed_out hook.
 */
static struct scsi_transport_template ata_scsi_transport_template = {
	.eh_strategy_handler	= ata_scsi_error,
	.eh_timed_out		= ata_scsi_timed_out,
	.user_scan		= ata_scsi_user_scan,
};


static const struct {
	enum link_pm	value;
	const char	*name;
} link_pm_policy[] = {
	{ NOT_AVAILABLE, "max_performance" },
	{ MIN_POWER, "min_power" },
	{ MAX_PERFORMANCE, "max_performance" },
	{ MEDIUM_POWER, "medium_power" },
};

static const char *ata_scsi_lpm_get(enum link_pm policy)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(link_pm_policy); i++)
		if (link_pm_policy[i].value == policy)
			return link_pm_policy[i].name;

	return NULL;
}

static ssize_t ata_scsi_lpm_put(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	struct Scsi_Host *shost = class_to_shost(dev);
	struct ata_port *ap = ata_shost_to_port(shost);
	enum link_pm policy = 0;
	int i;

	/*
	 * we are skipping array location 0 on purpose - this
	 * is because a value of NOT_AVAILABLE is displayed
	 * to the user as max_performance, but when the user
	 * writes "max_performance", they actually want the
	 * value to match MAX_PERFORMANCE.
	 */
	for (i = 1; i < ARRAY_SIZE(link_pm_policy); i++) {
		const int len = strlen(link_pm_policy[i].name);
		if (strncmp(link_pm_policy[i].name, buf, len) == 0 &&
		   buf[len] == '\n') {
			policy = link_pm_policy[i].value;
			break;
		}
	}
	if (!policy)
		return -EINVAL;

	ata_lpm_schedule(ap, policy);
	return count;
}

static ssize_t
ata_scsi_lpm_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(dev);
	struct ata_port *ap = ata_shost_to_port(shost);
	const char *policy =
		ata_scsi_lpm_get(ap->pm_policy);

	if (!policy)
		return -EINVAL;

	return snprintf(buf, 23, "%s\n", policy);
}
DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
		ata_scsi_lpm_show, ata_scsi_lpm_put);
EXPORT_SYMBOL_GPL(dev_attr_link_power_management_policy);

static void ata_scsi_set_sense(struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq)
{
	cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;

	scsi_build_sense_buffer(0, cmd->sense_buffer, sk, asc, ascq);
}

static void ata_scsi_invalid_field(struct scsi_cmnd *cmd,
				   void (*done)(struct scsi_cmnd *))
{
	ata_scsi_set_sense(cmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	done(cmd);
}

/**
 *	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;
}

/**
 *	ata_get_identity - Handler for HDIO_GET_IDENTITY ioctl
 *	@sdev: SCSI device to get identify data for
 *	@arg: User buffer area for identify data
 *
 *	LOCKING:
 *	Defined by the SCSI layer.  We don't really care.
 *
 *	RETURNS:
 *	Zero on success, negative errno on error.
 */
static int ata_get_identity(struct scsi_device *sdev, void __user *arg)
{
	struct ata_port *ap = ata_shost_to_port(sdev->host);
	struct ata_device *dev = ata_scsi_find_dev(ap, sdev);
	u16 __user *dst = arg;
	char buf[40];

	if (!dev)
		return -ENOMSG;

	if (copy_to_user(dst, dev->id, ATA_ID_WORDS * sizeof(u16)))
		return -EFAULT;

	ata_id_string(dev->id, buf, ATA_ID_PROD, ATA_ID_PROD_LEN);
	if (copy_to_user(dst + ATA_ID_PROD, buf, ATA_ID_PROD_LEN))
		return -EFAULT;

	ata_id_string(dev->id, buf, ATA_ID_FW_REV, ATA_ID_FW_REV_LEN);
	if (copy_to_user(dst + ATA_ID_FW_REV, buf, ATA_ID_FW_REV_LEN))
		return -EFAULT;

	ata_id_string(dev->id, buf, ATA_ID_SERNO, ATA_ID_SERNO_LEN);
	if (copy_to_user(dst + ATA_ID_SERNO, buf, ATA_ID_SERNO_LEN))
		return -EFAULT;

	return 0;
}

/**
 *	ata_cmd_ioctl - Handler for HDIO_DRIVE_CMD ioctl
 *	@scsidev: Device to which we are issuing command
 *	@arg: User provided data for issuing command
 *
 *	LOCKING:
 *	Defined by the SCSI layer.  We don't really care.
 *
 *	RETURNS:
 *	Zero on success, negative errno on error.
 */
int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg)
{
	int rc = 0;
	u8 scsi_cmd[MAX_COMMAND_SIZE];
	u8 args[4], *argbuf = NULL, *sensebuf = NULL;
	int argsize = 0;
	enum dma_data_direction data_dir;
	int cmd_result;

	if (arg == NULL)
		return -EINVAL;

	if (copy_from_user(args, arg, sizeof(args)))
		return -EFAULT;

	sensebuf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
	if (!sensebuf)
		return -ENOMEM;

	memset(scsi_cmd, 0, sizeof(scsi_cmd));

	if (args[3]) {
		argsize = SECTOR_SIZE * args[3];
		argbuf = kmalloc(argsize, GFP_KERNEL);
		if (argbuf == NULL) {
			rc = -ENOMEM;
			goto error;
		}

		scsi_cmd[1]  = (4 << 1); /* PIO Data-in */
		scsi_cmd[2]  = 0x0e;     /* no off.line or cc, read from dev,
					    block count in sector count field */
		data_dir = DMA_FROM_DEVICE;
	} else {
		scsi_cmd[1]  = (3 << 1); /* Non-data */
		scsi_cmd[2]  = 0x20;     /* cc but no off.line or data xfer */
		data_dir = DMA_NONE;
	}

	scsi_cmd[0] = ATA_16;

	scsi_cmd[4] = args[2];
	if (args[0] == WIN_SMART) { /* hack -- ide driver does this too... */
		scsi_cmd[6]  = args[3];
		scsi_cmd[8]  = args[1];
		scsi_cmd[10] = 0x4f;
		scsi_cmd[12] = 0xc2;
	} else {
		scsi_cmd[6]  = args[1];
	}
	scsi_cmd[14] = args[0];

	/* Good values for timeout and retries?  Values below
	   from scsi_ioctl_send_command() for default case... */
	cmd_result = scsi_execute(scsidev, scsi_cmd, data_dir, argbuf, argsize,
				  sensebuf, (10*HZ), 5, 0);

	if (driver_byte(cmd_result) == DRIVER_SENSE) {/* sense data available */
		u8 *desc = sensebuf + 8;
		cmd_result &= ~(0xFF<<24); /* DRIVER_SENSE is not an error */

		/* If we set cc then ATA pass-through will cause a
		 * check condition even if no error. Filter that. */
		if (cmd_result & SAM_STAT_CHECK_CONDITION) {
			struct scsi_sense_hdr sshdr;
			scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE,
					     &sshdr);
			if (sshdr.sense_key == 0 &&
			    sshdr.asc == 0 && sshdr.ascq == 0)
				cmd_result &= ~SAM_STAT_CHECK_CONDITION;
		}

		/* Send userspace a few ATA registers (same as drivers/ide) */
		if (sensebuf[0] == 0x72 &&	/* format is "descriptor" */
		    desc[0] == 0x09) {		/* code is "ATA Descriptor" */
			args[0] = desc[13];	/* status */
			args[1] = desc[3];	/* error */
			args[2] = desc[5];	/* sector count (0:7) */
			if (copy_to_user(arg, args, sizeof(args)))
				rc = -EFAULT;
		}
	}


	if (cmd_result) {
		rc = -EIO;
		goto error;
	}

	if ((argbuf)
	 && copy_to_user(arg + sizeof(args), argbuf, argsize))
		rc = -EFAULT;
error:
	kfree(sensebuf);
	kfree(argbuf);
	return rc;
}

/**
 *	ata_task_ioctl - Handler for HDIO_DRIVE_TASK ioctl
 *	@scsidev: Device to which we are issuing command
 *	@arg: User provided data for issuing command
 *
 *	LOCKING:
 *	Defined by the SCSI layer.  We don't really care.
 *
 *	RETURNS:
 *	Zero on success, negative errno on error.
 */
int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg)
{
	int rc = 0;
	u8 scsi_cmd[MAX_COMMAND_SIZE];
	u8 args[7], *sensebuf = NULL;
	int cmd_result;

	if (arg == NULL)
		return -EINVAL;

	if (copy_from_user(args, arg, sizeof(args)))
		return -EFAULT;

	sensebuf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
	if (!sensebuf)
		return -ENOMEM;

	memset(scsi_cmd, 0, sizeof(scsi_cmd));
	scsi_cmd[0]  = ATA_16;
	scsi_cmd[1]  = (3 << 1); /* Non-data */
	scsi_cmd[2]  = 0x20;     /* cc but no off.line or data xfer */
	scsi_cmd[4]  = args[1];
	scsi_cmd[6]  = args[2];
	scsi_cmd[8]  = args[3];
	scsi_cmd[10] = args[4];
	scsi_cmd[12] = args[5];
	scsi_cmd[13] = args[6] & 0x4f;
	scsi_cmd[14] = args[0];

	/* Good values for timeout and retries?  Values below
	   from scsi_ioctl_send_command() for default case... */
	cmd_result = scsi_execute(scsidev, scsi_cmd, DMA_NONE, NULL, 0,
				sensebuf, (10*HZ), 5, 0);

	if (driver_byte(cmd_result) == DRIVER_SENSE) {/* sense data available */
		u8 *desc = sensebuf + 8;
		cmd_result &= ~(0xFF<<24); /* DRIVER_SENSE is not an error */

		/* If we set cc then ATA pass-through will cause a
		 * check condition even if no error. Filter that. */
		if (cmd_result & SAM_STAT_CHECK_CONDITION) {
			struct scsi_sense_hdr sshdr;
			scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE,
						&sshdr);
			if (sshdr.sense_key == 0 &&
				sshdr.asc == 0 && sshdr.ascq == 0)
				cmd_result &= ~SAM_STAT_CHECK_CONDITION;
		}

		/* Send userspace ATA registers */
		if (sensebuf[0] == 0x72 &&	/* format is "descriptor" */
				desc[0] == 0x09) {/* code is "ATA Descriptor" */
			args[0] = desc[13];	/* status */
			args[1] = desc[3];	/* error */
			args[2] = desc[5];	/* sector count (0:7) */
			args[3] = desc[7];	/* lbal */
			args[4] = desc[9];	/* lbam */
			args[5] = desc[11];	/* lbah */
			args[6] = desc[12];	/* select */
			if (copy_to_user(arg, args, sizeof(args)))
				rc = -EFAULT;
		}
	}

	if (cmd_result) {
		rc = -EIO;
		goto error;
	}

 error:
	kfree(sensebuf);
	return rc;
}

int ata_scsi_ioctl(struct scsi_device *scsidev, int cmd, void __user *arg)
{
	int val = -EINVAL, rc = -EINVAL;

	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;

	case HDIO_GET_IDENTITY:
		return ata_get_identity(scsidev, arg);

	case HDIO_DRIVE_CMD:
		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
			return -EACCES;
		return ata_cmd_ioctl(scsidev, arg);

	case HDIO_DRIVE_TASK:
		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
			return -EACCES;
		return ata_task_ioctl(scsidev, arg);

	default:
		rc = -ENOTTY;
		break;
	}

	return rc;
}

/**
 *	ata_scsi_qc_new - acquire new ata_queued_cmd reference
 *	@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 lock)
 *
 *	RETURNS:
 *	Command allocated, or %NULL if none available.
 */
static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
					      struct scsi_cmnd *cmd,
					      void (*done)(struct scsi_cmnd *))
{
	struct ata_queued_cmd *qc;

	qc = ata_qc_new_init(dev);
	if (qc) {
		qc->scsicmd = cmd;
		qc->scsidone = done;

		qc->sg = scsi_sglist(cmd);
		qc->n_elem = scsi_sg_count(cmd);
	} else {
		cmd->result = (DID_OK << 16) | (QUEUE_FULL << 1);
		done(cmd);
	}

	return qc;
}

static void ata_qc_set_pc_nbytes(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;

	qc->extrabytes = scmd->request->extra_len;
	qc->nbytes = scsi_bufflen(scmd) + qc->extrabytes;
}

/**
 *	ata_dump_status - user friendly display of error info
 *	@id: id of the port in question
 *	@tf: ptr to filled out taskfile
 *
 *	Decode and dump the ATA error/status registers for the user so
 *	that they have some idea what really happened at the non
 *	make-believe layer.
 *
 *	LOCKING:
 *	inherited from caller
 */
static void ata_dump_status(unsigned id, struct ata_taskfile *tf)
{
	u8 stat = tf->command, err = tf->feature;

	printk(KERN_WARNING "ata%u: status=0x%02x { ", id, stat);
	if (stat & ATA_BUSY) {
		printk("Busy }\n");	/* Data is not valid in this case */
	} else {
		if (stat & 0x40)	printk("DriveReady ");
		if (stat & 0x20)	printk("DeviceFault ");
		if (stat & 0x10)	printk("SeekComplete ");
		if (stat & 0x08)	printk("DataRequest ");
		if (stat & 0x04)	printk("CorrectedError ");
		if (stat & 0x02)	printk("Index ");
		if (stat & 0x01)	printk("Error ");
		printk("}\n");

		if (err) {
			printk(KERN_WARNING "ata%u: error=0x%02x { ", 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");
		}
	}
}

/**
 *	ata_to_sense_error - convert ATA error to SCSI error
 *	@id: ATA device number
 *	@drv_stat: value contained in ATA status register
 *	@drv_err: value contained in ATA error register
 *	@sk: the sense key we'll fill out
 *	@asc: the additional sense code we'll fill out
 *	@ascq: the additional sense code qualifier we'll fill out
 *	@verbose: be verbose
 *
 *	Converts an ATA error into a SCSI error.  Fill out pointers to
 *	SK, ASC, and ASCQ bytes for later use in fixed or descriptor
 *	format sense blocks.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static void ata_to_sense_error(unsigned id, u8 drv_stat, u8 drv_err, u8 *sk,
			       u8 *asc, u8 *ascq, int verbose)
{
	int i;

	/* Based on the 3ware driver translation table */
	static const 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 const 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
	};

	/*
	 *	Is this an error we can process/parse
	 */
	if (drv_stat & ATA_BUSY) {
		drv_err = 0;	/* Ignore the err bits, they're invalid */
	}

	if (drv_err) {
		/* Look for drv_err */
		for (i = 0; sense_table[i][0] != 0xFF; i++) {
			/* Look for best matches first */
			if ((sense_table[i][0] & drv_err) ==
			    sense_table[i][0]) {
				*sk = sense_table[i][1];
				*asc = sense_table[i][2];
				*ascq = sense_table[i][3];
				goto translate_done;
			}
		}
		/* No immediate match */
		if (verbose)
			printk(KERN_WARNING "ata%u: no sense translation for "
			       "error 0x%02x\n", id, drv_err);
	}

	/* Fall back to interpreting status bits */
	for (i = 0; stat_table[i][0] != 0xFF; i++) {
		if (stat_table[i][0] & drv_stat) {
			*sk = stat_table[i][1];
			*asc = stat_table[i][2];
			*ascq = stat_table[i][3];
			goto translate_done;
		}
	}
	/* No error?  Undecoded? */
	if (verbose)
		printk(KERN_WARNING "ata%u: no sense translation for "
		       "status: 0x%02x\n", id, drv_stat);

	/* We need a sensible error return here, which is tricky, and one
	   that won't cause people to do things like return a disk wrongly */
	*sk = ABORTED_COMMAND;
	*asc = 0x00;
	*ascq = 0x00;

 translate_done:
	if (verbose)
		printk(KERN_ERR "ata%u: translated ATA stat/err 0x%02x/%02x "
		       "to SCSI SK/ASC/ASCQ 0x%x/%02x/%02x\n",
		       id, drv_stat, drv_err, *sk, *asc, *ascq);
	return;
}

/*
 *	ata_gen_passthru_sense - Generate check condition sense block.
 *	@qc: Command that completed.
 *
 *	This function is specific to the ATA descriptor format sense
 *	block specified for the ATA pass through commands.  Regardless
 *	of whether the command errored or not, return a sense
 *	block. Copy all controller registers into the sense
 *	block. Clear sense key, ASC & ASCQ if there is no error.
 *
 *	LOCKING:
 *	None.
 */
static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *cmd = qc->scsicmd;
	struct ata_taskfile *tf = &qc->result_tf;
	unsigned char *sb = cmd->sense_buffer;
	unsigned char *desc = sb + 8;
	int verbose = qc->ap->ops->error_handler == NULL;

	memset(sb, 0, SCSI_SENSE_BUFFERSIZE);

	cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;

	/*
	 * Use ata_to_sense_error() to map status register bits
	 * onto sense key, asc & ascq.
	 */
	if (qc->err_mask ||
	    tf->command & (ATA_BUSY | ATA_DF | ATA_ERR | ATA_DRQ)) {
		ata_to_sense_error(qc->ap->print_id, tf->command, tf->feature,
				   &sb[1], &sb[2], &sb[3], verbose);
		sb[1] &= 0x0f;
	}

	/*
	 * Sense data is current and format is descriptor.
	 */
	sb[0] = 0x72;

	desc[0] = 0x09;

	/* set length of additional sense data */
	sb[7] = 14;
	desc[1] = 12;

	/*
	 * Copy registers into sense buffer.
	 */
	desc[2] = 0x00;
	desc[3] = tf->feature;	/* == error reg */
	desc[5] = tf->nsect;
	desc[7] = tf->lbal;
	desc[9] = tf->lbam;
	desc[11] = tf->lbah;
	desc[12] = tf->device;
	desc[13] = tf->command; /* == status reg */

	/*
	 * Fill in Extend bit, and the high order bytes
	 * if applicable.
	 */
	if (tf->flags & ATA_TFLAG_LBA48) {
		desc[2] |= 0x01;
		desc[4] = tf->hob_nsect;
		desc[6] = tf->hob_lbal;
		desc[8] = tf->hob_lbam;
		desc[10] = tf->hob_lbah;
	}
}

/**
 *	ata_gen_ata_sense - generate a SCSI fixed sense block
 *	@qc: Command that we are erroring out
 *
 *	Generate sense block for a failed ATA command @qc.  Descriptor
 *	format is used to accomodate LBA48 block address.
 *
 *	LOCKING:
 *	None.
 */
static void ata_gen_ata_sense(struct ata_queued_cmd *qc)
{
	struct ata_device *dev = qc->dev;
	struct scsi_cmnd *cmd = qc->scsicmd;
	struct ata_taskfile *tf = &qc->result_tf;
	unsigned char *sb = cmd->sense_buffer;
	unsigned char *desc = sb + 8;
	int verbose = qc->ap->ops->error_handler == NULL;
	u64 block;

	memset(sb, 0, SCSI_SENSE_BUFFERSIZE);

	cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;

	/* sense data is current and format is descriptor */
	sb[0] = 0x72;

	/* Use ata_to_sense_error() to map status register bits
	 * onto sense key, asc & ascq.
	 */
	if (qc->err_mask ||
	    tf->command & (ATA_BUSY | ATA_DF | ATA_ERR | ATA_DRQ)) {
		ata_to_sense_error(qc->ap->print_id, tf->command, tf->feature,
				   &sb[1], &sb[2], &sb[3], verbose);
		sb[1] &= 0x0f;
	}

	block = ata_tf_read_block(&qc->result_tf, dev);

	/* information sense data descriptor */
	sb[7] = 12;
	desc[0] = 0x00;
	desc[1] = 10;

	desc[2] |= 0x80;	/* valid */
	desc[6] = block >> 40;
	desc[7] = block >> 32;
	desc[8] = block >> 24;
	desc[9] = block >> 16;
	desc[10] = block >> 8;
	desc[11] = block;
}

static void ata_scsi_sdev_config(struct scsi_device *sdev)
{
	sdev->use_10_for_rw = 1;
	sdev->use_10_for_ms = 1;

	/* Schedule policy is determined by ->qc_defer() callback and
	 * it needs to see every deferred qc.  Set dev_blocked to 1 to
	 * prevent SCSI midlayer from automatically deferring
	 * requests.
	 */
	sdev->max_device_blocked = 1;
}

/**
 *	atapi_drain_needed - Check whether data transfer may overflow
 *	@rq: request to be checked
 *
 *	ATAPI commands which transfer variable length data to host
 *	might overflow due to application error or hardare bug.  This
 *	function checks whether overflow should be drained and ignored
 *	for @request.
 *
 *	LOCKING:
 *	None.
 *
 *	RETURNS:
 *	1 if ; otherwise, 0.
 */
static int atapi_drain_needed(struct request *rq)
{
	if (likely(!blk_pc_request(rq)))
		return 0;

	if (!rq->data_len || (rq->cmd_flags & REQ_RW))
		return 0;

	return atapi_cmd_type(rq->cmd[0]) == ATAPI_MISC;
}

static int ata_scsi_dev_config(struct scsi_device *sdev,
			       struct ata_device *dev)
{
	/* configure max sectors */
	blk_queue_max_sectors(sdev->request_queue, dev->max_sectors);

	if (dev->class == ATA_DEV_ATAPI) {
		struct request_queue *q = sdev->request_queue;
		void *buf;

		/* set the min alignment and padding */
		blk_queue_update_dma_alignment(sdev->request_queue,
					       ATA_DMA_PAD_SZ - 1);
		blk_queue_dma_pad(sdev->request_queue, ATA_DMA_PAD_SZ - 1);

		/* configure draining */
		buf = kmalloc(ATAPI_MAX_DRAIN, q->bounce_gfp | GFP_KERNEL);
		if (!buf) {
			ata_dev_printk(dev, KERN_ERR,
				       "drain buffer allocation failed\n");
			return -ENOMEM;
		}

		blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);
	} else {
		/* ATA devices must be sector aligned */
		blk_queue_update_dma_alignment(sdev->request_queue,
					       ATA_SECT_SIZE - 1);
		sdev->manage_start_stop = 1;
	}

	if (dev->flags & ATA_DFLAG_AN)
		set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);

	if (dev->flags & ATA_DFLAG_NCQ) {
		int depth;

		depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
		depth = min(ATA_MAX_QUEUE - 1, depth);
		scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
	}

	return 0;
}

/**
 *	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)
{
	struct ata_port *ap = ata_shost_to_port(sdev->host);
	struct ata_device *dev = __ata_scsi_find_dev(ap, sdev);
	int rc = 0;

	ata_scsi_sdev_config(sdev);

	if (dev)
		rc = ata_scsi_dev_config(sdev, dev);

	return rc;
}

/**
 *	ata_scsi_slave_destroy - SCSI device is about to be destroyed
 *	@sdev: SCSI device to be destroyed
 *
 *	@sdev is about to be destroyed for hot/warm unplugging.  If
 *	this unplugging was initiated by libata as indicated by NULL
 *	dev->sdev, this function doesn't have to do anything.
 *	Otherwise, SCSI layer initiated warm-unplug is in progress.
 *	Clear dev->sdev, schedule the device for ATA detach and invoke
 *	EH.
 *
 *	LOCKING:
 *	Defined by SCSI layer.  We don't really care.
 */
void ata_scsi_slave_destroy(struct scsi_device *sdev)
{
	struct ata_port *ap = ata_shost_to_port(sdev->host);
	struct request_queue *q = sdev->request_queue;
	unsigned long flags;
	struct ata_device *dev;

	if (!ap->ops->error_handler)
		return;

	spin_lock_irqsave(ap->lock, flags);
	dev = __ata_scsi_find_dev(ap, sdev);
	if (dev && dev->sdev) {
		/* SCSI device already in CANCEL state, no need to offline it */
		dev->sdev = NULL;
		dev->flags |= ATA_DFLAG_DETACH;
		ata_port_schedule_eh(ap);
	}
	spin_unlock_irqrestore(ap->lock, flags);

	kfree(q->dma_drain_buffer);
	q->dma_drain_buffer = NULL;
	q->dma_drain_size = 0;
}

/**
 *	ata_scsi_change_queue_depth - SCSI callback for queue depth config
 *	@sdev: SCSI device to configure queue depth for
 *	@queue_depth: new queue depth
 *
 *	This is libata standard hostt->change_queue_depth callback.
 *	SCSI will call into this callback when user tries to set queue
 *	depth via sysfs.
 *
 *	LOCKING:
 *	SCSI layer (we don't care)
 *
 *	RETURNS:
 *	Newly configured queue depth.
 */
int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth)
{
	struct ata_port *ap = ata_shost_to_port(sdev->host);
	struct ata_device *dev;
	unsigned long flags;

	if (queue_depth < 1 || queue_depth == sdev->queue_depth)
		return sdev->queue_depth;

	dev = ata_scsi_find_dev(ap, sdev);
	if (!dev || !ata_dev_enabled(dev))
		return sdev->queue_depth;

	/* NCQ enabled? */
	spin_lock_irqsave(ap->lock, flags);
	dev->flags &= ~ATA_DFLAG_NCQ_OFF;
	if (queue_depth == 1 || !ata_ncq_enabled(dev)) {
		dev->flags |= ATA_DFLAG_NCQ_OFF;
		queue_depth = 1;
	}
	spin_unlock_irqrestore(ap->lock, flags);

	/* limit and apply queue depth */
	queue_depth = min(queue_depth, sdev->host->can_queue);
	queue_depth = min(queue_depth, ata_id_queue_depth(dev->id));
	queue_depth = min(queue_depth, ATA_MAX_QUEUE - 1);

	if (sdev->queue_depth == queue_depth)
		return -EINVAL;

	scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, queue_depth);
	return queue_depth;
}

/* XXX: for spindown warning */
static void ata_delayed_done_timerfn(unsigned long arg)
{
	struct scsi_cmnd *scmd = (void *)arg;

	scmd->scsi_done(scmd);
}

/* XXX: for spindown warning */
static void ata_delayed_done(struct scsi_cmnd *scmd)
{
	static struct timer_list timer;

	setup_timer(&timer, ata_delayed_done_timerfn, (unsigned long)scmd);
	mod_timer(&timer, jiffies + 5 * HZ);
}

/**
 *	ata_scsi_start_stop_xlat - Translate SCSI START STOP UNIT command
 *	@qc: Storage for translated ATA taskfile
 *
 *	Sets up an ATA taskfile to issue STANDBY (to stop) or READ VERIFY
 *	(to start). Perhaps these commands should be preceded by
 *	CHECK POWER MODE to see what power mode the device is already in.
 *	[See SAT revision 5 at www.t10.org]
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_start_stop_xlat(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	struct ata_taskfile *tf = &qc->tf;
	const u8 *cdb = scmd->cmnd;

	if (scmd->cmd_len < 5)
		goto invalid_fld;

	tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
	tf->protocol = ATA_PROT_NODATA;
	if (cdb[1] & 0x1) {
		;	/* ignore IMMED bit, violates sat-r05 */
	}
	if (cdb[4] & 0x2)
		goto invalid_fld;       /* LOEJ bit set not supported */
	if (((cdb[4] >> 4) & 0xf) != 0)
		goto invalid_fld;       /* power conditions not supported */

	if (cdb[4] & 0x1) {
		tf->nsect = 1;	/* 1 sector, lba=0 */

		if (qc->dev->flags & ATA_DFLAG_LBA) {
			tf->flags |= ATA_TFLAG_LBA;

			tf->lbah = 0x0;
			tf->lbam = 0x0;
			tf->lbal = 0x0;
			tf->device |= ATA_LBA;
		} else {
			/* CHS */
			tf->lbal = 0x1; /* sect */
			tf->lbam = 0x0; /* cyl low */
			tf->lbah = 0x0; /* cyl high */
		}

		tf->command = ATA_CMD_VERIFY;	/* READ VERIFY */
	} else {
		/* XXX: This is for backward compatibility, will be
		 * removed.  Read Documentation/feature-removal-schedule.txt
		 * for more info.
		 */
		if ((qc->dev->flags & ATA_DFLAG_SPUNDOWN) &&
		    (system_state == SYSTEM_HALT ||
		     system_state == SYSTEM_POWER_OFF)) {
			static unsigned long warned;

			if (!test_and_set_bit(0, &warned)) {
				ata_dev_printk(qc->dev, KERN_WARNING,
					"DISK MIGHT NOT BE SPUN DOWN PROPERLY. "
					"UPDATE SHUTDOWN UTILITY\n");
				ata_dev_printk(qc->dev, KERN_WARNING,
					"For more info, visit "
					"http://linux-ata.org/shutdown.html\n");

				/* ->scsi_done is not used, use it for
				 * delayed completion.
				 */
				scmd->scsi_done = qc->scsidone;
				qc->scsidone = ata_delayed_done;
			}
			scmd->result = SAM_STAT_GOOD;
			return 1;
		}

		/* Issue ATA STANDBY IMMEDIATE command */
		tf->command = ATA_CMD_STANDBYNOW1;
	}

	/*
	 * Standby and Idle condition timers could be implemented but that
	 * would require libata to implement the Power condition mode page
	 * and allow the user to change it. Changing mode pages requires
	 * MODE SELECT to be implemented.
	 */

	return 0;

invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;
}


/**
 *	ata_scsi_flush_xlat - Translate SCSI SYNCHRONIZE CACHE command
 *	@qc: Storage for translated ATA taskfile
 *
 *	Sets up an ATA taskfile to issue FLUSH CACHE or
 *	FLUSH CACHE EXT.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc)
{
	struct ata_taskfile *tf = &qc->tf;

	tf->flags |= ATA_TFLAG_DEVICE;
	tf->protocol = ATA_PROT_NODATA;

	if (qc->dev->flags & ATA_DFLAG_FLUSH_EXT)
		tf->command = ATA_CMD_FLUSH_EXT;
	else
		tf->command = ATA_CMD_FLUSH;

	/* flush is critical for IO integrity, consider it an IO command */
	qc->flags |= ATA_QCFLAG_IO;

	return 0;
}

/**
 *	scsi_6_lba_len - Get LBA and transfer length
 *	@cdb: SCSI command to translate
 *
 *	Calculate LBA and transfer length for 6-byte commands.
 *
 *	RETURNS:
 *	@plba: the LBA
 *	@plen: the transfer length
 */
static void scsi_6_lba_len(const u8 *cdb, u64 *plba, u32 *plen)
{
	u64 lba = 0;
	u32 len;

	VPRINTK("six-byte command\n");

	lba |= ((u64)(cdb[1] & 0x1f)) << 16;
	lba |= ((u64)cdb[2]) << 8;
	lba |= ((u64)cdb[3]);

	len = cdb[4];

	*plba = lba;
	*plen = len;
}

/**
 *	scsi_10_lba_len - Get LBA and transfer length
 *	@cdb: SCSI command to translate
 *
 *	Calculate LBA and transfer length for 10-byte commands.
 *
 *	RETURNS:
 *	@plba: the LBA
 *	@plen: the transfer length
 */
static void scsi_10_lba_len(const u8 *cdb, u64 *plba, u32 *plen)
{
	u64 lba = 0;
	u32 len = 0;

	VPRINTK("ten-byte command\n");

	lba |= ((u64)cdb[2]) << 24;
	lba |= ((u64)cdb[3]) << 16;
	lba |= ((u64)cdb[4]) << 8;
	lba |= ((u64)cdb[5]);

	len |= ((u32)cdb[7]) << 8;
	len |= ((u32)cdb[8]);

	*plba = lba;
	*plen = len;
}

/**
 *	scsi_16_lba_len - Get LBA and transfer length
 *	@cdb: SCSI command to translate
 *
 *	Calculate LBA and transfer length for 16-byte commands.
 *
 *	RETURNS:
 *	@plba: the LBA
 *	@plen: the transfer length
 */
static void scsi_16_lba_len(const u8 *cdb, u64 *plba, u32 *plen)
{
	u64 lba = 0;
	u32 len = 0;

	VPRINTK("sixteen-byte command\n");

	lba |= ((u64)cdb[2]) << 56;
	lba |= ((u64)cdb[3]) << 48;
	lba |= ((u64)cdb[4]) << 40;
	lba |= ((u64)cdb[5]) << 32;
	lba |= ((u64)cdb[6]) << 24;
	lba |= ((u64)cdb[7]) << 16;
	lba |= ((u64)cdb[8]) << 8;
	lba |= ((u64)cdb[9]);

	len |= ((u32)cdb[10]) << 24;
	len |= ((u32)cdb[11]) << 16;
	len |= ((u32)cdb[12]) << 8;
	len |= ((u32)cdb[13]);

	*plba = lba;
	*plen = len;
}

/**
 *	ata_scsi_verify_xlat - Translate SCSI VERIFY command into an ATA one
 *	@qc: Storage for translated ATA taskfile
 *
 *	Converts SCSI VERIFY command to an ATA READ VERIFY command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	struct ata_taskfile *tf = &qc->tf;
	struct ata_device *dev = qc->dev;
	u64 dev_sectors = qc->dev->n_sectors;
	const u8 *cdb = scmd->cmnd;
	u64 block;
	u32 n_block;

	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->protocol = ATA_PROT_NODATA;

	if (cdb[0] == VERIFY) {
		if (scmd->cmd_len < 10)
			goto invalid_fld;
		scsi_10_lba_len(cdb, &block, &n_block);
	} else if (cdb[0] == VERIFY_16) {
		if (scmd->cmd_len < 16)
			goto invalid_fld;
		scsi_16_lba_len(cdb, &block, &n_block);
	} else
		goto invalid_fld;

	if (!n_block)
		goto nothing_to_do;
	if (block >= dev_sectors)
		goto out_of_range;
	if ((block + n_block) > dev_sectors)
		goto out_of_range;

	if (dev->flags & ATA_DFLAG_LBA) {
		tf->flags |= ATA_TFLAG_LBA;

		if (lba_28_ok(block, n_block)) {
			/* use LBA28 */
			tf->command = ATA_CMD_VERIFY;
			tf->device |= (block >> 24) & 0xf;
		} else if (lba_48_ok(block, n_block)) {
			if (!(dev->flags & ATA_DFLAG_LBA48))
				goto out_of_range;

			/* use LBA48 */
			tf->flags |= ATA_TFLAG_LBA48;
			tf->command = ATA_CMD_VERIFY_EXT;

			tf->hob_nsect = (n_block >> 8) & 0xff;

			tf->hob_lbah = (block >> 40) & 0xff;
			tf->hob_lbam = (block >> 32) & 0xff;
			tf->hob_lbal = (block >> 24) & 0xff;
		} else
			/* request too large even for LBA48 */
			goto out_of_range;

		tf->nsect = n_block & 0xff;

		tf->lbah = (block >> 16) & 0xff;
		tf->lbam = (block >> 8) & 0xff;
		tf->lbal = block & 0xff;

		tf->device |= ATA_LBA;
	} else {
		/* CHS */
		u32 sect, head, cyl, track;

		if (!lba_28_ok(block, n_block))
			goto out_of_range;

		/* Convert LBA to CHS */
		track = (u32)block / dev->sectors;
		cyl   = track / dev->heads;
		head  = track % dev->heads;
		sect  = (u32)block % dev->sectors + 1;

		DPRINTK("block %u track %u cyl %u head %u sect %u\n",
			(u32)block, track, cyl, head, sect);

		/* Check whether the converted CHS can fit.
		   Cylinder: 0-65535
		   Head: 0-15
		   Sector: 1-255*/
		if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
			goto out_of_range;

		tf->command = ATA_CMD_VERIFY;
		tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
		tf->lbal = sect;
		tf->lbam = cyl;
		tf->lbah = cyl >> 8;
		tf->device |= head;
	}

	return 0;

invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;

out_of_range:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x21, 0x0);
	/* "Logical Block Address out of range" */
	return 1;

nothing_to_do:
	scmd->result = SAM_STAT_GOOD;
	return 1;
}

/**
 *	ata_scsi_rw_xlat - Translate SCSI r/w command into an ATA one
 *	@qc: Storage for translated ATA taskfile
 *
 *	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 lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	const u8 *cdb = scmd->cmnd;
	unsigned int tf_flags = 0;
	u64 block;
	u32 n_block;
	int rc;

	if (cdb[0] == WRITE_10 || cdb[0] == WRITE_6 || cdb[0] == WRITE_16)
		tf_flags |= ATA_TFLAG_WRITE;

	/* Calculate the SCSI LBA, transfer length and FUA. */
	switch (cdb[0]) {
	case READ_10:
	case WRITE_10:
		if (unlikely(scmd->cmd_len < 10))
			goto invalid_fld;
		scsi_10_lba_len(cdb, &block, &n_block);
		if (unlikely(cdb[1] & (1 << 3)))
			tf_flags |= ATA_TFLAG_FUA;
		break;
	case READ_6:
	case WRITE_6:
		if (unlikely(scmd->cmd_len < 6))
			goto invalid_fld;
		scsi_6_lba_len(cdb, &block, &n_block);

		/* for 6-byte r/w commands, transfer length 0
		 * means 256 blocks of data, not 0 block.
		 */
		if (!n_block)
			n_block = 256;
		break;
	case READ_16:
	case WRITE_16:
		if (unlikely(scmd->cmd_len < 16))
			goto invalid_fld;
		scsi_16_lba_len(cdb, &block, &n_block);
		if (unlikely(cdb[1] & (1 << 3)))
			tf_flags |= ATA_TFLAG_FUA;
		break;
	default:
		DPRINTK("no-byte command\n");
		goto invalid_fld;
	}

	/* Check and compose ATA command */
	if (!n_block)
		/* For 10-byte and 16-byte SCSI R/W commands, transfer
		 * length 0 means transfer 0 block of data.
		 * However, for ATA R/W commands, sector count 0 means
		 * 256 or 65536 sectors, not 0 sectors as in SCSI.
		 *
		 * WARNING: one or two older ATA drives treat 0 as 0...
		 */
		goto nothing_to_do;

	qc->flags |= ATA_QCFLAG_IO;
	qc->nbytes = n_block * ATA_SECT_SIZE;

	rc = ata_build_rw_tf(&qc->tf, qc->dev, block, n_block, tf_flags,
			     qc->tag);
	if (likely(rc == 0))
		return 0;

	if (rc == -ERANGE)
		goto out_of_range;
	/* treat all other errors as -EINVAL, fall through */
invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;

out_of_range:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x21, 0x0);
	/* "Logical Block Address out of range" */
	return 1;

nothing_to_do:
	scmd->result = SAM_STAT_GOOD;
	return 1;
}

static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct scsi_cmnd *cmd = qc->scsicmd;
	u8 *cdb = cmd->cmnd;
	int need_sense = (qc->err_mask != 0);

	/* For ATA pass thru (SAT) commands, generate a sense block if
	 * user mandated it or if there's an error.  Note that if we
	 * generate because the user forced us to, a check condition
	 * is generated and the ATA register values are returned
	 * whether the command completed successfully or not. If there
	 * was no error, SK, ASC and ASCQ will all be zero.
	 */
	if (((cdb[0] == ATA_16) || (cdb[0] == ATA_12)) &&
	    ((cdb[2] & 0x20) || need_sense)) {
		ata_gen_passthru_sense(qc);
	} else {
		if (!need_sense) {
			cmd->result = SAM_STAT_GOOD;
		} else {
			/* TODO: decide which descriptor format to use
			 * for 48b LBA devices and call that here
			 * instead of the fixed desc, which is only
			 * good for smaller LBA (and maybe CHS?)
			 * devices.
			 */
			ata_gen_ata_sense(qc);
		}
	}

	/* XXX: track spindown state for spindown skipping and warning */
	if (unlikely(qc->tf.command == ATA_CMD_STANDBY ||
		     qc->tf.command == ATA_CMD_STANDBYNOW1))
		qc->dev->flags |= ATA_DFLAG_SPUNDOWN;
	else if (likely(system_state != SYSTEM_HALT &&
			system_state != SYSTEM_POWER_OFF))
		qc->dev->flags &= ~ATA_DFLAG_SPUNDOWN;

	if (need_sense && !ap->ops->error_handler)
		ata_dump_status(ap->print_id, &qc->result_tf);

	qc->scsidone(cmd);

	ata_qc_free(qc);
}

/**
 *	ata_scsi_translate - Translate then issue SCSI command to ATA device
 *	@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.
 *
 *	The xlat_func argument (actor) returns 0 if ready to execute
 *	ATA command, else 1 to finish translation. If 1 is returned
 *	then cmd->result (and possibly cmd->sense_buffer) are assumed
 *	to be set reflecting an error condition or clean (early)
 *	termination.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	0 on success, SCSI_ML_QUEUE_DEVICE_BUSY if the command
 *	needs to be deferred.
 */
static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
			      void (*done)(struct scsi_cmnd *),
			      ata_xlat_func_t xlat_func)
{
	struct ata_port *ap = dev->link->ap;
	struct ata_queued_cmd *qc;
	int rc;

	VPRINTK("ENTER\n");

	qc = ata_scsi_qc_new(dev, cmd, done);
	if (!qc)
		goto err_mem;

	/* data is present; dma-map it */
	if (cmd->sc_data_direction == DMA_FROM_DEVICE ||
	    cmd->sc_data_direction == DMA_TO_DEVICE) {
		if (unlikely(scsi_bufflen(cmd) < 1)) {
			ata_dev_printk(dev, KERN_WARNING,
				       "WARNING: zero len r/w req\n");
			goto err_did;
		}

		ata_sg_init(qc, scsi_sglist(cmd), scsi_sg_count(cmd));

		qc->dma_dir = cmd->sc_data_direction;
	}

	qc->complete_fn = ata_scsi_qc_complete;

	if (xlat_func(qc))
		goto early_finish;

	if (ap->ops->qc_defer) {
		if ((rc = ap->ops->qc_defer(qc)))
			goto defer;
	}

	/* select device, send command to hardware */
	ata_qc_issue(qc);

	VPRINTK("EXIT\n");
	return 0;

early_finish:
	ata_qc_free(qc);
	qc->scsidone(cmd);
	DPRINTK("EXIT - early finish (good or error)\n");
	return 0;

err_did:
	ata_qc_free(qc);
	cmd->result = (DID_ERROR << 16);
	qc->scsidone(cmd);
err_mem:
	DPRINTK("EXIT - internal\n");
	return 0;

defer:
	ata_qc_free(qc);
	DPRINTK("EXIT - defer\n");
	if (rc == ATA_DEFER_LINK)
		return SCSI_MLQUEUE_DEVICE_BUSY;
	else
		return SCSI_MLQUEUE_HOST_BUSY;
}

/**
 *	ata_scsi_rbuf_get - Map response buffer.
 *	@cmd: SCSI command containing buffer to be mapped.
 *	@flags: unsigned long variable to store irq enable status
 *	@copy_in: copy in from user buffer
 *
 *	Prepare buffer for simulated SCSI commands.
 *
 *	LOCKING:
 *	spin_lock_irqsave(ata_scsi_rbuf_lock) on success
 *
 *	RETURNS:
 *	Pointer to response buffer.
 */
static void *ata_scsi_rbuf_get(struct scsi_cmnd *cmd, bool copy_in,
			       unsigned long *flags)
{
	spin_lock_irqsave(&ata_scsi_rbuf_lock, *flags);

	memset(ata_scsi_rbuf, 0, ATA_SCSI_RBUF_SIZE);
	if (copy_in)
		sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
				  ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
	return ata_scsi_rbuf;
}

/**
 *	ata_scsi_rbuf_put - Unmap response buffer.
 *	@cmd: SCSI command containing buffer to be unmapped.
 *	@copy_out: copy out result
 *	@flags: @flags passed to ata_scsi_rbuf_get()
 *
 *	Returns rbuf buffer.  The result is copied to @cmd's buffer if
 *	@copy_back is true.
 *
 *	LOCKING:
 *	Unlocks ata_scsi_rbuf_lock.
 */
static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, bool copy_out,
				     unsigned long *flags)
{
	if (copy_out)
		sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
				    ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
	spin_unlock_irqrestore(&ata_scsi_rbuf_lock, *flags);
}

/**
 *	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 (0), or not (in which case cmd->result
 *	and sense buffer are assumed to be set).
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
		unsigned int (*actor)(struct ata_scsi_args *args, u8 *rbuf))
{
	u8 *rbuf;
	unsigned int rc;
	struct scsi_cmnd *cmd = args->cmd;
	unsigned long flags;

	rbuf = ata_scsi_rbuf_get(cmd, false, &flags);
	rc = actor(args, rbuf);
	ata_scsi_rbuf_put(cmd, rc == 0, &flags);

	if (rc == 0)
		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.
 *
 *	Returns standard device identification data associated
 *	with non-VPD INQUIRY command output.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf)
{
	const u8 versions[] = {
		0x60,	/* SAM-3 (no version claimed) */

		0x03,
		0x20,	/* SBC-2 (no version claimed) */

		0x02,
		0x60	/* SPC-3 (no version claimed) */
	};
	u8 hdr[] = {
		TYPE_DISK,
		0,
		0x5,	/* claim SPC-3 version compatibility */
		2,
		95 - 4
	};

	VPRINTK("ENTER\n");

	/* set scsi removeable (RMB) bit per ata bit */
	if (ata_id_removeable(args->id))
		hdr[1] |= (1 << 7);

	memcpy(rbuf, hdr, sizeof(hdr));
	memcpy(&rbuf[8], "ATA     ", 8);
	ata_id_string(args->id, &rbuf[16], ATA_ID_PROD, 16);
	ata_id_string(args->id, &rbuf[32], ATA_ID_FW_REV, 4);

	if (rbuf[32] == 0 || rbuf[32] == ' ')
		memcpy(&rbuf[32], "n/a ", 4);

	memcpy(rbuf + 59, versions, sizeof(versions));

	return 0;
}

/**
 *	ata_scsiop_inq_00 - Simulate INQUIRY VPD page 0, list of pages
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *
 *	Returns list of inquiry VPD pages available.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_inq_00(struct ata_scsi_args *args, u8 *rbuf)
{
	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 VPD pages */
	memcpy(rbuf + 4, pages, sizeof(pages));
	return 0;
}

/**
 *	ata_scsiop_inq_80 - Simulate INQUIRY VPD page 80, device serial number
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *
 *	Returns ATA device serial number.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_inq_80(struct ata_scsi_args *args, u8 *rbuf)
{
	const u8 hdr[] = {
		0,
		0x80,			/* this page code */
		0,
		ATA_ID_SERNO_LEN,	/* page len */
	};

	memcpy(rbuf, hdr, sizeof(hdr));
	ata_id_string(args->id, (unsigned char *) &rbuf[4],
		      ATA_ID_SERNO, ATA_ID_SERNO_LEN);
	return 0;
}

/**
 *	ata_scsiop_inq_83 - Simulate INQUIRY VPD page 83, device identity
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *
 *	Yields two logical unit device identification designators:
 *	 - vendor specific ASCII containing the ATA serial number
 *	 - SAT defined "t10 vendor id based" containing ASCII vendor
 *	   name ("ATA     "), model and serial numbers.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf)
{
	const int sat_model_serial_desc_len = 68;
	int num;

	rbuf[1] = 0x83;			/* this page code */
	num = 4;

	/* piv=0, assoc=lu, code_set=ACSII, designator=vendor */
	rbuf[num + 0] = 2;
	rbuf[num + 3] = ATA_ID_SERNO_LEN;
	num += 4;
	ata_id_string(args->id, (unsigned char *) rbuf + num,
		      ATA_ID_SERNO, ATA_ID_SERNO_LEN);
	num += ATA_ID_SERNO_LEN;

	/* SAT defined lu model and serial numbers descriptor */
	/* piv=0, assoc=lu, code_set=ACSII, designator=t10 vendor id */
	rbuf[num + 0] = 2;
	rbuf[num + 1] = 1;
	rbuf[num + 3] = sat_model_serial_desc_len;
	num += 4;
	memcpy(rbuf + num, "ATA     ", 8);
	num += 8;
	ata_id_string(args->id, (unsigned char *) rbuf + num, ATA_ID_PROD,
		      ATA_ID_PROD_LEN);
	num += ATA_ID_PROD_LEN;
	ata_id_string(args->id, (unsigned char *) rbuf + num, ATA_ID_SERNO,
		      ATA_ID_SERNO_LEN);
	num += ATA_ID_SERNO_LEN;

	rbuf[3] = num - 4;    /* page len (assume less than 256 bytes) */
	return 0;
}

/**
 *	ata_scsiop_inq_89 - Simulate INQUIRY VPD page 89, ATA info
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *
 *	Yields SAT-specified ATA VPD page.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_inq_89(struct ata_scsi_args *args, u8 *rbuf)
{
	struct ata_taskfile tf;

	memset(&tf, 0, sizeof(tf));

	rbuf[1] = 0x89;			/* our page code */
	rbuf[2] = (0x238 >> 8);		/* page size fixed at 238h */
	rbuf[3] = (0x238 & 0xff);

	memcpy(&rbuf[8], "linux   ", 8);
	memcpy(&rbuf[16], "libata          ", 16);
	memcpy(&rbuf[32], DRV_VERSION, 4);
	ata_id_string(args->id, &rbuf[32], ATA_ID_FW_REV, 4);

	/* we don't store the ATA device signature, so we fake it */

	tf.command = ATA_DRDY;		/* really, this is Status reg */
	tf.lbal = 0x1;
	tf.nsect = 0x1;

	ata_tf_to_fis(&tf, 0, 1, &rbuf[36]);	/* TODO: PMP? */
	rbuf[36] = 0x34;		/* force D2H Reg FIS (34h) */

	rbuf[56] = ATA_CMD_ID_ATA;

	memcpy(&rbuf[60], &args->id[0], 512);
	return 0;
}

/**
 *	ata_scsiop_noop - Command handler that simply returns success.
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *
 *	No operation.  Simply returns success to caller, to indicate
 *	that the caller should successfully complete this SCSI command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_noop(struct ata_scsi_args *args, u8 *rbuf)
{
	VPRINTK("ENTER\n");
	return 0;
}

/**
 *	ata_msense_caching - Simulate MODE SENSE caching info page
 *	@id: device IDENTIFY data
 *	@buf: output 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 *buf)
{
	memcpy(buf, def_cache_mpage, sizeof(def_cache_mpage));
	if (ata_id_wcache_enabled(id))
		buf[2] |= (1 << 2);	/* write cache enable */
	if (!ata_id_rahead_enabled(id))
		buf[12] |= (1 << 5);	/* disable read ahead */
	return sizeof(def_cache_mpage);
}

/**
 *	ata_msense_ctl_mode - Simulate MODE SENSE control mode page
 *	@buf: output buffer
 *
 *	Generate a generic MODE SENSE control mode page.
 *
 *	LOCKING:
 *	None.
 */
static unsigned int ata_msense_ctl_mode(u8 *buf)
{
	memcpy(buf, def_control_mpage, sizeof(def_control_mpage));
	return sizeof(def_control_mpage);
}

/**
 *	ata_msense_rw_recovery - Simulate MODE SENSE r/w error recovery page
 *	@buf: output buffer
 *
 *	Generate a generic MODE SENSE r/w error recovery page.
 *
 *	LOCKING:
 *	None.
 */
static unsigned int ata_msense_rw_recovery(u8 *buf)
{
	memcpy(buf, def_rw_recovery_mpage, sizeof(def_rw_recovery_mpage));
	return sizeof(def_rw_recovery_mpage);
}

/*
 * We can turn this into a real blacklist if it's needed, for now just
 * blacklist any Maxtor BANC1G10 revision firmware
 */
static int ata_dev_supports_fua(u16 *id)
{
	unsigned char model[ATA_ID_PROD_LEN + 1], fw[ATA_ID_FW_REV_LEN + 1];

	if (!libata_fua)
		return 0;
	if (!ata_id_has_fua(id))
		return 0;

	ata_id_c_string(id, model, ATA_ID_PROD, sizeof(model));
	ata_id_c_string(id, fw, ATA_ID_FW_REV, sizeof(fw));

	if (strcmp(model, "Maxtor"))
		return 1;
	if (strcmp(fw, "BANC1G10"))
		return 1;

	return 0; /* blacklisted */
}

/**
 *	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.
 *
 *	Simulate MODE SENSE commands. Assume this is invoked for direct
 *	access devices (e.g. disks) only. There should be no block
 *	descriptor for other device types.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
{
	struct ata_device *dev = args->dev;
	u8 *scsicmd = args->cmd->cmnd, *p = rbuf;
	const u8 sat_blk_desc[] = {
		0, 0, 0, 0,	/* number of blocks: sat unspecified */
		0,
		0, 0x2, 0x0	/* block length: 512 bytes */
	};
	u8 pg, spg;
	unsigned int ebd, page_control, six_byte;
	u8 dpofua;

	VPRINTK("ENTER\n");

	six_byte = (scsicmd[0] == MODE_SENSE);
	ebd = !(scsicmd[1] & 0x8);      /* dbd bit inverted == edb */
	/*
	 * LLBA bit in msense(10) ignored (compliant)
	 */

	page_control = scsicmd[2] >> 6;
	switch (page_control) {
	case 0: /* current */
		break;  /* supported */
	case 3: /* saved */
		goto saving_not_supp;
	case 1: /* changeable */
	case 2: /* defaults */
	default:
		goto invalid_fld;
	}

	if (six_byte)
		p += 4 + (ebd ? 8 : 0);
	else
		p += 8 + (ebd ? 8 : 0);

	pg = scsicmd[2] & 0x3f;
	spg = scsicmd[3];
	/*
	 * No mode subpages supported (yet) but asking for _all_
	 * subpages may be valid
	 */
	if (spg && (spg != ALL_SUB_MPAGES))
		goto invalid_fld;

	switch(pg) {
	case RW_RECOVERY_MPAGE:
		p += ata_msense_rw_recovery(p);
		break;

	case CACHE_MPAGE:
		p += ata_msense_caching(args->id, p);
		break;

	case CONTROL_MPAGE:
		p += ata_msense_ctl_mode(p);
		break;

	case ALL_MPAGES:
		p += ata_msense_rw_recovery(p);
		p += ata_msense_caching(args->id, p);
		p += ata_msense_ctl_mode(p);
		break;

	default:		/* invalid page code */
		goto invalid_fld;
	}

	dpofua = 0;
	if (ata_dev_supports_fua(args->id) && (dev->flags & ATA_DFLAG_LBA48) &&
	    (!(dev->flags & ATA_DFLAG_PIO) || dev->multi_count))
		dpofua = 1 << 4;

	if (six_byte) {
		rbuf[0] = p - rbuf - 1;
		rbuf[2] |= dpofua;
		if (ebd) {
			rbuf[3] = sizeof(sat_blk_desc);
			memcpy(rbuf + 4, sat_blk_desc, sizeof(sat_blk_desc));
		}
	} else {
		unsigned int output_len = p - rbuf - 2;

		rbuf[0] = output_len >> 8;
		rbuf[1] = output_len;
		rbuf[3] |= dpofua;
		if (ebd) {
			rbuf[7] = sizeof(sat_blk_desc);
			memcpy(rbuf + 8, sat_blk_desc, sizeof(sat_blk_desc));
		}
	}
	return 0;

invalid_fld:
	ata_scsi_set_sense(args->cmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;

saving_not_supp:
	ata_scsi_set_sense(args->cmd, ILLEGAL_REQUEST, 0x39, 0x0);
	 /* "Saving parameters not supported" */
	return 1;
}

/**
 *	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.
 *
 *	Simulate READ CAPACITY commands.
 *
 *	LOCKING:
 *	None.
 */
static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
{
	u64 last_lba = args->dev->n_sectors - 1; /* LBA of the last block */

	VPRINTK("ENTER\n");

	if (args->cmd->cmnd[0] == READ_CAPACITY) {
		if (last_lba >= 0xffffffffULL)
			last_lba = 0xffffffff;

		/* sector count, 32-bit */
		rbuf[0] = last_lba >> (8 * 3);
		rbuf[1] = last_lba >> (8 * 2);
		rbuf[2] = last_lba >> (8 * 1);
		rbuf[3] = last_lba;

		/* sector size */
		rbuf[6] = ATA_SECT_SIZE >> 8;
		rbuf[7] = ATA_SECT_SIZE & 0xff;
	} else {
		/* sector count, 64-bit */
		rbuf[0] = last_lba >> (8 * 7);
		rbuf[1] = last_lba >> (8 * 6);
		rbuf[2] = last_lba >> (8 * 5);
		rbuf[3] = last_lba >> (8 * 4);
		rbuf[4] = last_lba >> (8 * 3);
		rbuf[5] = last_lba >> (8 * 2);
		rbuf[6] = last_lba >> (8 * 1);
		rbuf[7] = last_lba;

		/* sector size */
		rbuf[10] = ATA_SECT_SIZE >> 8;
		rbuf[11] = ATA_SECT_SIZE & 0xff;
	}

	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.
 *
 *	Simulate REPORT LUNS command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static unsigned int ata_scsiop_report_luns(struct ata_scsi_args *args, u8 *rbuf)
{
	VPRINTK("ENTER\n");
	rbuf[3] = 8;	/* just one lun, LUN 0, size 8 bytes */

	return 0;
}

static void atapi_sense_complete(struct ata_queued_cmd *qc)
{
	if (qc->err_mask && ((qc->err_mask & AC_ERR_DEV) == 0)) {
		/* FIXME: not quite right; we don't want the
		 * translation of taskfile registers into
		 * a sense descriptors, since that's only
		 * correct for ATA, not ATAPI
		 */
		ata_gen_passthru_sense(qc);
	}

	qc->scsidone(qc->scsicmd);
	ata_qc_free(qc);
}

/* is it pointless to prefer PIO for "safety reasons"? */
static inline int ata_pio_use_silly(struct ata_port *ap)
{
	return (ap->flags & ATA_FLAG_PIO_DMA);
}

static void atapi_request_sense(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct scsi_cmnd *cmd = qc->scsicmd;

	DPRINTK("ATAPI request sense\n");

	/* FIXME: is this needed? */
	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);

#ifdef CONFIG_ATA_SFF
	if (ap->ops->sff_tf_read)
		ap->ops->sff_tf_read(ap, &qc->tf);
#endif

	/* fill these in, for the case where they are -not- overwritten */
	cmd->sense_buffer[0] = 0x70;
	cmd->sense_buffer[2] = qc->tf.feature >> 4;

	ata_qc_reinit(qc);

	/* setup sg table and init transfer direction */
	sg_init_one(&qc->sgent, cmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
	ata_sg_init(qc, &qc->sgent, 1);
	qc->dma_dir = DMA_FROM_DEVICE;

	memset(&qc->cdb, 0, qc->dev->cdb_len);
	qc->cdb[0] = REQUEST_SENSE;
	qc->cdb[4] = SCSI_SENSE_BUFFERSIZE;

	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	qc->tf.command = ATA_CMD_PACKET;

	if (ata_pio_use_silly(ap)) {
		qc->tf.protocol = ATAPI_PROT_DMA;
		qc->tf.feature |= ATAPI_PKT_DMA;
	} else {
		qc->tf.protocol = ATAPI_PROT_PIO;
		qc->tf.lbam = SCSI_SENSE_BUFFERSIZE;
		qc->tf.lbah = 0;
	}
	qc->nbytes = SCSI_SENSE_BUFFERSIZE;

	qc->complete_fn = atapi_sense_complete;

	ata_qc_issue(qc);

	DPRINTK("EXIT\n");
}

static void atapi_qc_complete(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *cmd = qc->scsicmd;
	unsigned int err_mask = qc->err_mask;

	VPRINTK("ENTER, err_mask 0x%X\n", err_mask);

	/* handle completion from new EH */
	if (unlikely(qc->ap->ops->error_handler &&
		     (err_mask || qc->flags & ATA_QCFLAG_SENSE_VALID))) {

		if (!(qc->flags & ATA_QCFLAG_SENSE_VALID)) {
			/* FIXME: not quite right; we don't want the
			 * translation of taskfile registers into a
			 * sense descriptors, since that's only
			 * correct for ATA, not ATAPI
			 */
			ata_gen_passthru_sense(qc);
		}

		/* SCSI EH automatically locks door if sdev->locked is
		 * set.  Sometimes door lock request continues to
		 * fail, for example, when no media is present.  This
		 * creates a loop - SCSI EH issues door lock which
		 * fails and gets invoked again to acquire sense data
		 * for the failed command.
		 *
		 * If door lock fails, always clear sdev->locked to
		 * avoid this infinite loop.
		 */
		if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL)
			qc->dev->sdev->locked = 0;

		qc->scsicmd->result = SAM_STAT_CHECK_CONDITION;
		qc->scsidone(cmd);
		ata_qc_free(qc);
		return;
	}

	/* successful completion or old EH failure path */
	if (unlikely(err_mask & AC_ERR_DEV)) {
		cmd->result = SAM_STAT_CHECK_CONDITION;
		atapi_request_sense(qc);
		return;
	} else if (unlikely(err_mask)) {
		/* FIXME: not quite right; we don't want the
		 * translation of taskfile registers into
		 * a sense descriptors, since that's only
		 * correct for ATA, not ATAPI
		 */
		ata_gen_passthru_sense(qc);
	} else {
		u8 *scsicmd = cmd->cmnd;

		if ((scsicmd[0] == INQUIRY) && ((scsicmd[1] & 0x03) == 0)) {
			unsigned long flags;
			u8 *buf;

			buf = ata_scsi_rbuf_get(cmd, true, &flags);

	/* ATAPI devices typically report zero for their SCSI version,
	 * and sometimes deviate from the spec WRT response data
	 * format.  If SCSI version is reported as zero like normal,
	 * then we make the following fixups:  1) Fake MMC-5 version,
	 * to indicate to the Linux scsi midlayer this is a modern
	 * device.  2) Ensure response data format / ATAPI information
	 * are always correct.
	 */
			if (buf[2] == 0) {
				buf[2] = 0x5;
				buf[3] = 0x32;
			}

			ata_scsi_rbuf_put(cmd, true, &flags);
		}

		cmd->result = SAM_STAT_GOOD;
	}

	qc->scsidone(cmd);
	ata_qc_free(qc);
}
/**
 *	atapi_xlat - Initialize PACKET taskfile
 *	@qc: command structure to be initialized
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on failure.
 */
static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	struct ata_device *dev = qc->dev;
	int using_pio = (dev->flags & ATA_DFLAG_PIO);
	int nodata = (scmd->sc_data_direction == DMA_NONE);
	unsigned int nbytes;

	memset(qc->cdb, 0, dev->cdb_len);
	memcpy(qc->cdb, scmd->cmnd, scmd->cmd_len);

	qc->complete_fn = atapi_qc_complete;

	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	if (scmd->sc_data_direction == DMA_TO_DEVICE) {
		qc->tf.flags |= ATA_TFLAG_WRITE;
		DPRINTK("direction: write\n");
	}

	qc->tf.command = ATA_CMD_PACKET;
	ata_qc_set_pc_nbytes(qc);

	/* check whether ATAPI DMA is safe */
	if (!using_pio && ata_check_atapi_dma(qc))
		using_pio = 1;

	/* Some controller variants snoop this value for Packet
	 * transfers to do state machine and FIFO management.  Thus we
	 * want to set it properly, and for DMA where it is
	 * effectively meaningless.
	 */
	nbytes = min(ata_qc_raw_nbytes(qc), (unsigned int)63 * 1024);

	/* Most ATAPI devices which honor transfer chunk size don't
	 * behave according to the spec when odd chunk size which
	 * matches the transfer length is specified.  If the number of
	 * bytes to transfer is 2n+1.  According to the spec, what
	 * should happen is to indicate that 2n+1 is going to be
	 * transferred and transfer 2n+2 bytes where the last byte is
	 * padding.
	 *
	 * In practice, this doesn't happen.  ATAPI devices first
	 * indicate and transfer 2n bytes and then indicate and
	 * transfer 2 bytes where the last byte is padding.
	 *
	 * This inconsistency confuses several controllers which
	 * perform PIO using DMA such as Intel AHCIs and sil3124/32.
	 * These controllers use actual number of transferred bytes to
	 * update DMA poitner and transfer of 4n+2 bytes make those
	 * controller push DMA pointer by 4n+4 bytes because SATA data
	 * FISes are aligned to 4 bytes.  This causes data corruption
	 * and buffer overrun.
	 *
	 * Always setting nbytes to even number solves this problem
	 * because then ATAPI devices don't have to split data at 2n
	 * boundaries.
	 */
	if (nbytes & 0x1)
		nbytes++;

	qc->tf.lbam = (nbytes & 0xFF);
	qc->tf.lbah = (nbytes >> 8);

	if (using_pio || nodata) {
		/* no data, or PIO data xfer */
		if (nodata)
			qc->tf.protocol = ATAPI_PROT_NODATA;
		else
			qc->tf.protocol = ATAPI_PROT_PIO;
	} else {
		/* DMA data xfer */
		qc->tf.protocol = ATAPI_PROT_DMA;
		qc->tf.feature |= ATAPI_PKT_DMA;

		if ((dev->flags & ATA_DFLAG_DMADIR) &&
		    (scmd->sc_data_direction != DMA_TO_DEVICE))
			/* some SATA bridges need us to indicate data xfer direction */
			qc->tf.feature |= ATAPI_DMADIR;
	}


	/* FIXME: We need to translate 0x05 READ_BLOCK_LIMITS to a MODE_SENSE
	   as ATAPI tape drives don't get this right otherwise */
	return 0;
}

static struct ata_device *ata_find_dev(struct ata_port *ap, int devno)
{
	if (!sata_pmp_attached(ap)) {
		if (likely(devno < ata_link_max_devices(&ap->link)))
			return &ap->link.device[devno];
	} else {
		if (likely(devno < ap->nr_pmp_links))
			return &ap->pmp_link[devno].device[0];
	}

	return NULL;
}

static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
					      const struct scsi_device *scsidev)
{
	int devno;

	/* skip commands not addressed to targets we simulate */
	if (!sata_pmp_attached(ap)) {
		if (unlikely(scsidev->channel || scsidev->lun))
			return NULL;
		devno = scsidev->id;
	} else {
		if (unlikely(scsidev->id || scsidev->lun))
			return NULL;
		devno = scsidev->channel;
	}

	return ata_find_dev(ap, devno);
}

/**
 *	ata_scsi_dev_enabled - determine if device is enabled
 *	@dev: ATA device
 *
 *	Determine if commands should be sent to the specified device.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	0 if commands are not allowed / 1 if commands are allowed
 */

static int ata_scsi_dev_enabled(struct ata_device *dev)
{
	if (unlikely(!ata_dev_enabled(dev)))
		return 0;

	if (!atapi_enabled || (dev->link->ap->flags & ATA_FLAG_NO_ATAPI)) {
		if (unlikely(dev->class == ATA_DEV_ATAPI)) {
			ata_dev_printk(dev, KERN_WARNING,
				       "WARNING: ATAPI is %s, device ignored.\n",
				       atapi_enabled ? "not supported with this driver" : "disabled");
			return 0;
		}
	}

	return 1;
}

/**
 *	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 lock)
 *
 *	RETURNS:
 *	Associated ATA device, or %NULL if not found.
 */
static struct ata_device *
ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
{
	struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);

	if (unlikely(!dev || !ata_scsi_dev_enabled(dev)))
		return NULL;

	return dev;
}

/*
 *	ata_scsi_map_proto - Map pass-thru protocol value to taskfile value.
 *	@byte1: Byte 1 from pass-thru CDB.
 *
 *	RETURNS:
 *	ATA_PROT_UNKNOWN if mapping failed/unimplemented, protocol otherwise.
 */
static u8
ata_scsi_map_proto(u8 byte1)
{
	switch((byte1 & 0x1e) >> 1) {
	case 3:		/* Non-data */
		return ATA_PROT_NODATA;

	case 6:		/* DMA */
	case 10:	/* UDMA Data-in */
	case 11:	/* UDMA Data-Out */
		return ATA_PROT_DMA;

	case 4:		/* PIO Data-in */
	case 5:		/* PIO Data-out */
		return ATA_PROT_PIO;

	case 0:		/* Hard Reset */
	case 1:		/* SRST */
	case 8:		/* Device Diagnostic */
	case 9:		/* Device Reset */
	case 7:		/* DMA Queued */
	case 12:	/* FPDMA */
	case 15:	/* Return Response Info */
	default:	/* Reserved */
		break;
	}

	return ATA_PROT_UNKNOWN;
}

/**
 *	ata_scsi_pass_thru - convert ATA pass-thru CDB to taskfile
 *	@qc: command structure to be initialized
 *
 *	Handles either 12 or 16-byte versions of the CDB.
 *
 *	RETURNS:
 *	Zero on success, non-zero on failure.
 */
static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
{
	struct ata_taskfile *tf = &(qc->tf);
	struct scsi_cmnd *scmd = qc->scsicmd;
	struct ata_device *dev = qc->dev;
	const u8 *cdb = scmd->cmnd;

	if ((tf->protocol = ata_scsi_map_proto(cdb[1])) == ATA_PROT_UNKNOWN)
		goto invalid_fld;

	/*
	 * Filter TPM commands by default. These provide an
	 * essentially uncontrolled encrypted "back door" between
	 * applications and the disk. Set libata.allow_tpm=1 if you
	 * have a real reason for wanting to use them. This ensures
	 * that installed software cannot easily mess stuff up without
	 * user intent. DVR type users will probably ship with this enabled
	 * for movie content management.
	 *
	 * Note that for ATA8 we can issue a DCS change and DCS freeze lock
	 * for this and should do in future but that it is not sufficient as
	 * DCS is an optional feature set. Thus we also do the software filter
	 * so that we comply with the TC consortium stated goal that the user
	 * can turn off TC features of their system.
	 */
	if (tf->command >= 0x5C && tf->command <= 0x5F && !libata_allow_tpm)
		goto invalid_fld;

	/* We may not issue DMA commands if no DMA mode is set */
	if (tf->protocol == ATA_PROT_DMA && dev->dma_mode == 0)
		goto invalid_fld;

	/*
	 * 12 and 16 byte CDBs use different offsets to
	 * provide the various register values.
	 */
	if (cdb[0] == ATA_16) {
		/*
		 * 16-byte CDB - may contain extended commands.
		 *
		 * If that is the case, copy the upper byte register values.
		 */
		if (cdb[1] & 0x01) {
			tf->hob_feature = cdb[3];
			tf->hob_nsect = cdb[5];
			tf->hob_lbal = cdb[7];
			tf->hob_lbam = cdb[9];
			tf->hob_lbah = cdb[11];
			tf->flags |= ATA_TFLAG_LBA48;
		} else
			tf->flags &= ~ATA_TFLAG_LBA48;

		/*
		 * Always copy low byte, device and command registers.
		 */
		tf->feature = cdb[4];
		tf->nsect = cdb[6];
		tf->lbal = cdb[8];
		tf->lbam = cdb[10];
		tf->lbah = cdb[12];
		tf->device = cdb[13];
		tf->command = cdb[14];
	} else {
		/*
		 * 12-byte CDB - incapable of extended commands.
		 */
		tf->flags &= ~ATA_TFLAG_LBA48;

		tf->feature = cdb[3];
		tf->nsect = cdb[4];
		tf->lbal = cdb[5];
		tf->lbam = cdb[6];
		tf->lbah = cdb[7];
		tf->device = cdb[8];
		tf->command = cdb[9];
	}

	/* enforce correct master/slave bit */
	tf->device = dev->devno ?
		tf->device | ATA_DEV1 : tf->device & ~ATA_DEV1;

	/* sanity check for pio multi commands */
	if ((cdb[1] & 0xe0) && !is_multi_taskfile(tf))
		goto invalid_fld;

	if (is_multi_taskfile(tf)) {
		unsigned int multi_count = 1 << (cdb[1] >> 5);

		/* compare the passed through multi_count
		 * with the cached multi_count of libata
		 */
		if (multi_count != dev->multi_count)
			ata_dev_printk(dev, KERN_WARNING,
				       "invalid multi_count %u ignored\n",
				       multi_count);
	}

	/* READ/WRITE LONG use a non-standard sect_size */
	qc->sect_size = ATA_SECT_SIZE;
	switch (tf->command) {
	case ATA_CMD_READ_LONG:
	case ATA_CMD_READ_LONG_ONCE:
	case ATA_CMD_WRITE_LONG:
	case ATA_CMD_WRITE_LONG_ONCE:
		if (tf->protocol != ATA_PROT_PIO || tf->nsect != 1)
			goto invalid_fld;
		qc->sect_size = scsi_bufflen(scmd);
	}

	/*
	 * Filter SET_FEATURES - XFER MODE command -- otherwise,
	 * SET_FEATURES - XFER MODE must be preceded/succeeded
	 * by an update to hardware-specific registers for each
	 * controller (i.e. the reason for ->set_piomode(),
	 * ->set_dmamode(), and ->post_set_mode() hooks).
	 */
	if ((tf->command == ATA_CMD_SET_FEATURES)
	 && (tf->feature == SETFEATURES_XFER))
		goto invalid_fld;

	/*
	 * Set flags so that all registers will be written,
	 * and pass on write indication (used for PIO/DMA
	 * setup.)
	 */
	tf->flags |= (ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE);

	if (scmd->sc_data_direction == DMA_TO_DEVICE)
		tf->flags |= ATA_TFLAG_WRITE;

	/*
	 * Set transfer length.
	 *
	 * TODO: find out if we need to do more here to
	 *       cover scatter/gather case.
	 */
	ata_qc_set_pc_nbytes(qc);

	/* request result TF and be quiet about device error */
	qc->flags |= ATA_QCFLAG_RESULT_TF | ATA_QCFLAG_QUIET;

	return 0;

 invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x00);
	/* "Invalid field in cdb" */
	return 1;
}

/**
 *	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;

	case ATA_12:
	case ATA_16:
		return ata_scsi_pass_thru;

	case START_STOP:
		return ata_scsi_start_stop_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->print_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
}

static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
				      void (*done)(struct scsi_cmnd *),
				      struct ata_device *dev)
{
	u8 scsi_op = scmd->cmnd[0];
	ata_xlat_func_t xlat_func;
	int rc = 0;

	if (dev->class == ATA_DEV_ATA) {
		if (unlikely(!scmd->cmd_len || scmd->cmd_len > dev->cdb_len))
			goto bad_cdb_len;

		xlat_func = ata_get_xlat_func(dev, scsi_op);
	} else {
		if (unlikely(!scmd->cmd_len))
			goto bad_cdb_len;

		xlat_func = NULL;
		if (likely((scsi_op != ATA_16) || !atapi_passthru16)) {
			/* relay SCSI command to ATAPI device */
			int len = COMMAND_SIZE(scsi_op);
			if (unlikely(len > scmd->cmd_len || len > dev->cdb_len))
				goto bad_cdb_len;

			xlat_func = atapi_xlat;
		} else {
			/* ATA_16 passthru, treat as an ATA command */
			if (unlikely(scmd->cmd_len > 16))
				goto bad_cdb_len;

			xlat_func = ata_get_xlat_func(dev, scsi_op);
		}
	}

	if (xlat_func)
		rc = ata_scsi_translate(dev, scmd, done, xlat_func);
	else
		ata_scsi_simulate(dev, scmd, done);

	return rc;

 bad_cdb_len:
	DPRINTK("bad CDB len=%u, scsi_op=0x%02x, max=%u\n",
		scmd->cmd_len, scsi_op, dev->cdb_len);
	scmd->result = DID_ERROR << 16;
	done(scmd);
	return 0;
}

/**
 *	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 lock.
 *
 *	RETURNS:
 *	Return value from __ata_scsi_queuecmd() if @cmd can be queued,
 *	0 otherwise.
 */
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;
	struct Scsi_Host *shost = scsidev->host;
	int rc = 0;

	ap = ata_shost_to_port(shost);

	spin_unlock(shost->host_lock);
	spin_lock(ap->lock);

	ata_scsi_dump_cdb(ap, cmd);

	dev = ata_scsi_find_dev(ap, scsidev);
	if (likely(dev))
		rc = __ata_scsi_queuecmd(cmd, done, dev);
	else {
		cmd->result = (DID_BAD_TARGET << 16);
		done(cmd);
	}

	spin_unlock(ap->lock);
	spin_lock(shost->host_lock);
	return rc;
}

/**
 *	ata_scsi_simulate - simulate SCSI command on ATA device
 *	@dev: the 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 lock)
 */

void ata_scsi_simulate(struct ata_device *dev, struct scsi_cmnd *cmd,
		      void (*done)(struct scsi_cmnd *))
{
	struct ata_scsi_args args;
	const u8 *scsicmd = cmd->cmnd;
	u8 tmp8;

	args.dev = dev;
	args.id = dev->id;
	args.cmd = cmd;
	args.done = done;

	switch(scsicmd[0]) {
	/* TODO: worth improving? */
	case FORMAT_UNIT:
		ata_scsi_invalid_field(cmd, done);
		break;

	case INQUIRY:
		if (scsicmd[1] & 2)	           /* is CmdDt set?  */
			ata_scsi_invalid_field(cmd, done);
		else if ((scsicmd[1] & 1) == 0)    /* is EVPD clear? */
			ata_scsi_rbuf_fill(&args, ata_scsiop_inq_std);
		else switch (scsicmd[2]) {
		case 0x00:
			ata_scsi_rbuf_fill(&args, ata_scsiop_inq_00);
			break;
		case 0x80:
			ata_scsi_rbuf_fill(&args, ata_scsiop_inq_80);
			break;
		case 0x83:
			ata_scsi_rbuf_fill(&args, ata_scsiop_inq_83);
			break;
		case 0x89:
			ata_scsi_rbuf_fill(&args, ata_scsiop_inq_89);
			break;
		default:
			ata_scsi_invalid_field(cmd, done);
			break;
		}
		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_scsi_invalid_field(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_scsi_invalid_field(cmd, done);
		break;

	case REPORT_LUNS:
		ata_scsi_rbuf_fill(&args, ata_scsiop_report_luns);
		break;

	case REQUEST_SENSE:
		ata_scsi_set_sense(cmd, 0, 0, 0);
		cmd->result = (DRIVER_SENSE << 24);
		done(cmd);
		break;

	/* if we reach this, then writeback caching is disabled,
	 * turning this into a no-op.
	 */
	case SYNCHRONIZE_CACHE:
		/* fall through */

	/* no-op's, complete with success */
	case REZERO_UNIT:
	case SEEK_6:
	case SEEK_10:
	case TEST_UNIT_READY:
		ata_scsi_rbuf_fill(&args, ata_scsiop_noop);
		break;

	case SEND_DIAGNOSTIC:
		tmp8 = scsicmd[1] & ~(1 << 3);
		if ((tmp8 == 0x4) && (!scsicmd[3]) && (!scsicmd[4]))
			ata_scsi_rbuf_fill(&args, ata_scsiop_noop);
		else
			ata_scsi_invalid_field(cmd, done);
		break;

	/* all other commands */
	default:
		ata_scsi_set_sense(cmd, ILLEGAL_REQUEST, 0x20, 0x0);
		/* "Invalid command operation code" */
		done(cmd);
		break;
	}
}

int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
{
	int i, rc;

	for (i = 0; i < host->n_ports; i++) {
		struct ata_port *ap = host->ports[i];
		struct Scsi_Host *shost;

		rc = -ENOMEM;
		shost = scsi_host_alloc(sht, sizeof(struct ata_port *));
		if (!shost)
			goto err_alloc;

		*(struct ata_port **)&shost->hostdata[0] = ap;
		ap->scsi_host = shost;

		shost->transportt = &ata_scsi_transport_template;
		shost->unique_id = ap->print_id;
		shost->max_id = 16;
		shost->max_lun = 1;
		shost->max_channel = 1;
		shost->max_cmd_len = 16;

		/* Schedule policy is determined by ->qc_defer()
		 * callback and it needs to see every deferred qc.
		 * Set host_blocked to 1 to prevent SCSI midlayer from
		 * automatically deferring requests.
		 */
		shost->max_host_blocked = 1;

		rc = scsi_add_host(ap->scsi_host, ap->host->dev);
		if (rc)
			goto err_add;
	}

	return 0;

 err_add:
	scsi_host_put(host->ports[i]->scsi_host);
 err_alloc:
	while (--i >= 0) {
		struct Scsi_Host *shost = host->ports[i]->scsi_host;

		scsi_remove_host(shost);
		scsi_host_put(shost);
	}
	return rc;
}

void ata_scsi_scan_host(struct ata_port *ap, int sync)
{
	int tries = 5;
	struct ata_device *last_failed_dev = NULL;
	struct ata_link *link;
	struct ata_device *dev;

	if (ap->flags & ATA_FLAG_DISABLED)
		return;

 repeat:
	ata_port_for_each_link(link, ap) {
		ata_link_for_each_dev(dev, link) {
			struct scsi_device *sdev;
			int channel = 0, id = 0;

			if (!ata_dev_enabled(dev) || dev->sdev)
				continue;

			if (ata_is_host_link(link))
				id = dev->devno;
			else
				channel = link->pmp;

			sdev = __scsi_add_device(ap->scsi_host, channel, id, 0,
						 NULL);
			if (!IS_ERR(sdev)) {
				dev->sdev = sdev;
				scsi_device_put(sdev);
			}
		}
	}

	/* If we scanned while EH was in progress or allocation
	 * failure occurred, scan would have failed silently.  Check
	 * whether all devices are attached.
	 */
	ata_port_for_each_link(link, ap) {
		ata_link_for_each_dev(dev, link) {
			if (ata_dev_enabled(dev) && !dev->sdev)
				goto exit_loop;
		}
	}
 exit_loop:
	if (!link)
		return;

	/* we're missing some SCSI devices */
	if (sync) {
		/* If caller requested synchrnous scan && we've made
		 * any progress, sleep briefly and repeat.
		 */
		if (dev != last_failed_dev) {
			msleep(100);
			last_failed_dev = dev;
			goto repeat;
		}

		/* We might be failing to detect boot device, give it
		 * a few more chances.
		 */
		if (--tries) {
			msleep(100);
			goto repeat;
		}

		ata_port_printk(ap, KERN_ERR, "WARNING: synchronous SCSI scan "
				"failed without making any progress,\n"
				"                  switching to async\n");
	}

	queue_delayed_work(ata_aux_wq, &ap->hotplug_task,
			   round_jiffies_relative(HZ));
}

/**
 *	ata_scsi_offline_dev - offline attached SCSI device
 *	@dev: ATA device to offline attached SCSI device for
 *
 *	This function is called from ata_eh_hotplug() and responsible
 *	for taking the SCSI device attached to @dev offline.  This
 *	function is called with host lock which protects dev->sdev
 *	against clearing.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	1 if attached SCSI device exists, 0 otherwise.
 */
int ata_scsi_offline_dev(struct ata_device *dev)
{
	if (dev->sdev) {
		scsi_device_set_state(dev->sdev, SDEV_OFFLINE);
		return 1;
	}
	return 0;
}

/**
 *	ata_scsi_remove_dev - remove attached SCSI device
 *	@dev: ATA device to remove attached SCSI device for
 *
 *	This function is called from ata_eh_scsi_hotplug() and
 *	responsible for removing the SCSI device attached to @dev.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
static void ata_scsi_remove_dev(struct ata_device *dev)
{
	struct ata_port *ap = dev->link->ap;
	struct scsi_device *sdev;
	unsigned long flags;

	/* Alas, we need to grab scan_mutex to ensure SCSI device
	 * state doesn't change underneath us and thus
	 * scsi_device_get() always succeeds.  The mutex locking can
	 * be removed if there is __scsi_device_get() interface which
	 * increments reference counts regardless of device state.
	 */
	mutex_lock(&ap->scsi_host->scan_mutex);
	spin_lock_irqsave(ap->lock, flags);

	/* clearing dev->sdev is protected by host lock */
	sdev = dev->sdev;
	dev->sdev = NULL;

	if (sdev) {
		/* If user initiated unplug races with us, sdev can go
		 * away underneath us after the host lock and
		 * scan_mutex are released.  Hold onto it.
		 */
		if (scsi_device_get(sdev) == 0) {
			/* The following ensures the attached sdev is
			 * offline on return from ata_scsi_offline_dev()
			 * regardless it wins or loses the race
			 * against this function.
			 */
			scsi_device_set_state(sdev, SDEV_OFFLINE);
		} else {
			WARN_ON(1);
			sdev = NULL;
		}
	}

	spin_unlock_irqrestore(ap->lock, flags);
	mutex_unlock(&ap->scsi_host->scan_mutex);

	if (sdev) {
		ata_dev_printk(dev, KERN_INFO, "detaching (SCSI %s)\n",
			       sdev->sdev_gendev.bus_id);

		scsi_remove_device(sdev);
		scsi_device_put(sdev);
	}
}

static void ata_scsi_handle_link_detach(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ata_device *dev;

	ata_link_for_each_dev(dev, link) {
		unsigned long flags;

		if (!(dev->flags & ATA_DFLAG_DETACHED))
			continue;

		spin_lock_irqsave(ap->lock, flags);
		dev->flags &= ~ATA_DFLAG_DETACHED;
		spin_unlock_irqrestore(ap->lock, flags);

		ata_scsi_remove_dev(dev);
	}
}

/**
 *	ata_scsi_media_change_notify - send media change event
 *	@dev: Pointer to the disk device with media change event
 *
 *	Tell the block layer to send a media change notification
 *	event.
 *
 * 	LOCKING:
 * 	spin_lock_irqsave(host lock)
 */
void ata_scsi_media_change_notify(struct ata_device *dev)
{
	if (dev->sdev)
		sdev_evt_send_simple(dev->sdev, SDEV_EVT_MEDIA_CHANGE,
				     GFP_ATOMIC);
}

/**
 *	ata_scsi_hotplug - SCSI part of hotplug
 *	@work: Pointer to ATA port to perform SCSI hotplug on
 *
 *	Perform SCSI part of hotplug.  It's executed from a separate
 *	workqueue after EH completes.  This is necessary because SCSI
 *	hot plugging requires working EH and hot unplugging is
 *	synchronized with hot plugging with a mutex.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_scsi_hotplug(struct work_struct *work)
{
	struct ata_port *ap =
		container_of(work, struct ata_port, hotplug_task.work);
	int i;

	if (ap->pflags & ATA_PFLAG_UNLOADING) {
		DPRINTK("ENTER/EXIT - unloading\n");
		return;
	}

	DPRINTK("ENTER\n");

	/* Unplug detached devices.  We cannot use link iterator here
	 * because PMP links have to be scanned even if PMP is
	 * currently not attached.  Iterate manually.
	 */
	ata_scsi_handle_link_detach(&ap->link);
	if (ap->pmp_link)
		for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
			ata_scsi_handle_link_detach(&ap->pmp_link[i]);

	/* scan for new ones */
	ata_scsi_scan_host(ap, 0);

	DPRINTK("EXIT\n");
}

/**
 *	ata_scsi_user_scan - indication for user-initiated bus scan
 *	@shost: SCSI host to scan
 *	@channel: Channel to scan
 *	@id: ID to scan
 *	@lun: LUN to scan
 *
 *	This function is called when user explicitly requests bus
 *	scan.  Set probe pending flag and invoke EH.
 *
 *	LOCKING:
 *	SCSI layer (we don't care)
 *
 *	RETURNS:
 *	Zero.
 */
static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
			      unsigned int id, unsigned int lun)
{
	struct ata_port *ap = ata_shost_to_port(shost);
	unsigned long flags;
	int devno, rc = 0;

	if (!ap->ops->error_handler)
		return -EOPNOTSUPP;

	if (lun != SCAN_WILD_CARD && lun)
		return -EINVAL;

	if (!sata_pmp_attached(ap)) {
		if (channel != SCAN_WILD_CARD && channel)
			return -EINVAL;
		devno = id;
	} else {
		if (id != SCAN_WILD_CARD && id)
			return -EINVAL;
		devno = channel;
	}

	spin_lock_irqsave(ap->lock, flags);

	if (devno == SCAN_WILD_CARD) {
		struct ata_link *link;

		ata_port_for_each_link(link, ap) {
			struct ata_eh_info *ehi = &link->eh_info;
			ehi->probe_mask |= ATA_ALL_DEVICES;
			ehi->action |= ATA_EH_RESET;
		}
	} else {
		struct ata_device *dev = ata_find_dev(ap, devno);

		if (dev) {
			struct ata_eh_info *ehi = &dev->link->eh_info;
			ehi->probe_mask |= 1 << dev->devno;
			ehi->action |= ATA_EH_RESET;
		} else
			rc = -EINVAL;
	}

	if (rc == 0) {
		ata_port_schedule_eh(ap);
		spin_unlock_irqrestore(ap->lock, flags);
		ata_port_wait_eh(ap);
	} else
		spin_unlock_irqrestore(ap->lock, flags);

	return rc;
}

/**
 *	ata_scsi_dev_rescan - initiate scsi_rescan_device()
 *	@work: Pointer to ATA port to perform scsi_rescan_device()
 *
 *	After ATA pass thru (SAT) commands are executed successfully,
 *	libata need to propagate the changes to SCSI layer.  This
 *	function must be executed from ata_aux_wq such that sdev
 *	attach/detach don't race with rescan.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_scsi_dev_rescan(struct work_struct *work)
{
	struct ata_port *ap =
		container_of(work, struct ata_port, scsi_rescan_task);
	struct ata_link *link;
	struct ata_device *dev;
	unsigned long flags;

	spin_lock_irqsave(ap->lock, flags);

	ata_port_for_each_link(link, ap) {
		ata_link_for_each_dev(dev, link) {
			struct scsi_device *sdev = dev->sdev;

			if (!ata_dev_enabled(dev) || !sdev)
				continue;
			if (scsi_device_get(sdev))
				continue;

			spin_unlock_irqrestore(ap->lock, flags);
			scsi_rescan_device(&(sdev->sdev_gendev));
			scsi_device_put(sdev);
			spin_lock_irqsave(ap->lock, flags);
		}
	}

	spin_unlock_irqrestore(ap->lock, flags);
}

/**
 *	ata_sas_port_alloc - Allocate port for a SAS attached SATA device
 *	@host: ATA host container for all SAS ports
 *	@port_info: Information from low-level host driver
 *	@shost: SCSI host that the scsi device is attached to
 *
 *	LOCKING:
 *	PCI/etc. bus probe sem.
 *
 *	RETURNS:
 *	ata_port pointer on success / NULL on failure.
 */

struct ata_port *ata_sas_port_alloc(struct ata_host *host,
				    struct ata_port_info *port_info,
				    struct Scsi_Host *shost)
{
	struct ata_port *ap;

	ap = ata_port_alloc(host);
	if (!ap)
		return NULL;

	ap->port_no = 0;
	ap->lock = shost->host_lock;
	ap->pio_mask = port_info->pio_mask;
	ap->mwdma_mask = port_info->mwdma_mask;
	ap->udma_mask = port_info->udma_mask;
	ap->flags |= port_info->flags;
	ap->ops = port_info->port_ops;
	ap->cbl = ATA_CBL_SATA;

	return ap;
}
EXPORT_SYMBOL_GPL(ata_sas_port_alloc);

/**
 *	ata_sas_port_start - Set port up for dma.
 *	@ap: Port to initialize
 *
 *	Called just after data structures for each port are
 *	initialized.
 *
 *	May be used as the port_start() entry in ata_port_operations.
 *
 *	LOCKING:
 *	Inherited from caller.
 */
int ata_sas_port_start(struct ata_port *ap)
{
	return 0;
}
EXPORT_SYMBOL_GPL(ata_sas_port_start);

/**
 *	ata_port_stop - Undo ata_sas_port_start()
 *	@ap: Port to shut down
 *
 *	May be used as the port_stop() entry in ata_port_operations.
 *
 *	LOCKING:
 *	Inherited from caller.
 */

void ata_sas_port_stop(struct ata_port *ap)
{
}
EXPORT_SYMBOL_GPL(ata_sas_port_stop);

/**
 *	ata_sas_port_init - Initialize a SATA device
 *	@ap: SATA port to initialize
 *
 *	LOCKING:
 *	PCI/etc. bus probe sem.
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */

int ata_sas_port_init(struct ata_port *ap)
{
	int rc = ap->ops->port_start(ap);

	if (!rc) {
		ap->print_id = ata_print_id++;
		rc = ata_bus_probe(ap);
	}

	return rc;
}
EXPORT_SYMBOL_GPL(ata_sas_port_init);

/**
 *	ata_sas_port_destroy - Destroy a SATA port allocated by ata_sas_port_alloc
 *	@ap: SATA port to destroy
 *
 */

void ata_sas_port_destroy(struct ata_port *ap)
{
	if (ap->ops->port_stop)
		ap->ops->port_stop(ap);
	kfree(ap);
}
EXPORT_SYMBOL_GPL(ata_sas_port_destroy);

/**
 *	ata_sas_slave_configure - Default slave_config routine for libata devices
 *	@sdev: SCSI device to configure
 *	@ap: ATA port to which SCSI device is attached
 *
 *	RETURNS:
 *	Zero.
 */

int ata_sas_slave_configure(struct scsi_device *sdev, struct ata_port *ap)
{
	ata_scsi_sdev_config(sdev);
	ata_scsi_dev_config(sdev, ap->link.device);
	return 0;
}
EXPORT_SYMBOL_GPL(ata_sas_slave_configure);

/**
 *	ata_sas_queuecmd - Issue SCSI cdb to libata-managed device
 *	@cmd: SCSI command to be sent
 *	@done: Completion function, called when command is complete
 *	@ap:	ATA port to which the command is being sent
 *
 *	RETURNS:
 *	Return value from __ata_scsi_queuecmd() if @cmd can be queued,
 *	0 otherwise.
 */

int ata_sas_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *),
		     struct ata_port *ap)
{
	int rc = 0;

	ata_scsi_dump_cdb(ap, cmd);

	if (likely(ata_scsi_dev_enabled(ap->link.device)))
		rc = __ata_scsi_queuecmd(cmd, done, ap->link.device);
	else {
		cmd->result = (DID_BAD_TARGET << 16);
		done(cmd);
	}
	return rc;
}
EXPORT_SYMBOL_GPL(ata_sas_queuecmd);