Merge branch 'linus' into x86/timers

[linux-2.6] / drivers / ata / libata-scsi.c

/*
 *  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 nodata = (scmd->sc_data_direction == DMA_NONE);
        int using_pio = !nodata && (dev->flags & ATA_DFLAG_PIO);
        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 (!nodata && !using_pio && atapi_check_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 (nodata)
                qc->tf.protocol = ATAPI_PROT_NODATA;
        else if (using_pio)
                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);