libata-scsi.c

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/*
 *  libata-scsi.c - helper library for ATA
 *
 *  Maintained by:  Jeff Garzik <[email protected]>
 *              Please ALWAYS copy [email protected]
 *          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/slab.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/spinlock.h>
#include <linux/export.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 <linux/suspend.h>
#include <asm/unaligned.h>

#include "libata.h"
#include "libata-transport.h"

#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);

#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 */
};

static const char *ata_lpm_policy_names[] = {
    [ATA_LPM_UNKNOWN]   = "max_performance",
    [ATA_LPM_MAX_POWER] = "max_performance",
    [ATA_LPM_MED_POWER] = "medium_power",
    [ATA_LPM_MIN_POWER] = "min_power",
};

static ssize_t ata_scsi_lpm_store(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 ata_lpm_policy policy;
    unsigned long flags;

    /* UNKNOWN is internal state, iterate from MAX_POWER */
    for (policy = ATA_LPM_MAX_POWER;
         policy < ARRAY_SIZE(ata_lpm_policy_names); policy++) {
        const char *name = ata_lpm_policy_names[policy];

        if (strncmp(name, buf, strlen(name)) == 0)
            break;
    }
    if (policy == ARRAY_SIZE(ata_lpm_policy_names))
        return -EINVAL;

    spin_lock_irqsave(ap->lock, flags);
    ap->target_lpm_policy = policy;
    ata_port_schedule_eh(ap);
    spin_unlock_irqrestore(ap->lock, flags);

    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);

    if (ap->target_lpm_policy >= ARRAY_SIZE(ata_lpm_policy_names))
        return -EINVAL;

    return snprintf(buf, PAGE_SIZE, "%s\n",
            ata_lpm_policy_names[ap->target_lpm_policy]);
}
DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
        ata_scsi_lpm_show, ata_scsi_lpm_store);
EXPORT_SYMBOL_GPL(dev_attr_link_power_management_policy);

static ssize_t ata_scsi_park_show(struct device *device,
                  struct device_attribute *attr, char *buf)
{
    struct scsi_device *sdev = to_scsi_device(device);
    struct ata_port *ap;
    struct ata_link *link;
    struct ata_device *dev;
    unsigned long flags, now;
    unsigned int uninitialized_var(msecs);
    int rc = 0;

    ap = ata_shost_to_port(sdev->host);

    spin_lock_irqsave(ap->lock, flags);
    dev = ata_scsi_find_dev(ap, sdev);
    if (!dev) {
        rc = -ENODEV;
        goto unlock;
    }
    if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
        rc = -EOPNOTSUPP;
        goto unlock;
    }

    link = dev->link;
    now = jiffies;
    if (ap->pflags & ATA_PFLAG_EH_IN_PROGRESS &&
        link->eh_context.unloaded_mask & (1 << dev->devno) &&
        time_after(dev->unpark_deadline, now))
        msecs = jiffies_to_msecs(dev->unpark_deadline - now);
    else
        msecs = 0;

unlock:
    spin_unlock_irq(ap->lock);

    return rc ? rc : snprintf(buf, 20, "%u\n", msecs);
}

static ssize_t ata_scsi_park_store(struct device *device,
                   struct device_attribute *attr,
                   const char *buf, size_t len)
{
    struct scsi_device *sdev = to_scsi_device(device);
    struct ata_port *ap;
    struct ata_device *dev;
    long int input;
    unsigned long flags;
    int rc;

    rc = strict_strtol(buf, 10, &input);
    if (rc || input < -2)
        return -EINVAL;
    if (input > ATA_TMOUT_MAX_PARK) {
        rc = -EOVERFLOW;
        input = ATA_TMOUT_MAX_PARK;
    }

    ap = ata_shost_to_port(sdev->host);

    spin_lock_irqsave(ap->lock, flags);
    dev = ata_scsi_find_dev(ap, sdev);
    if (unlikely(!dev)) {
        rc = -ENODEV;
        goto unlock;
    }
    if (dev->class != ATA_DEV_ATA) {
        rc = -EOPNOTSUPP;
        goto unlock;
    }

    if (input >= 0) {
        if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
            rc = -EOPNOTSUPP;
            goto unlock;
        }

        dev->unpark_deadline = ata_deadline(jiffies, input);
        dev->link->eh_info.dev_action[dev->devno] |= ATA_EH_PARK;
        ata_port_schedule_eh(ap);
        complete(&ap->park_req_pending);
    } else {
        switch (input) {
        case -1:
            dev->flags &= ~ATA_DFLAG_NO_UNLOAD;
            break;
        case -2:
            dev->flags |= ATA_DFLAG_NO_UNLOAD;
            break;
        }
    }
unlock:
    spin_unlock_irqrestore(ap->lock, flags);

    return rc ? rc : len;
}
DEVICE_ATTR(unload_heads, S_IRUGO | S_IWUSR,
        ata_scsi_park_show, ata_scsi_park_store);
EXPORT_SYMBOL_GPL(dev_attr_unload_heads);

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 ssize_t
ata_scsi_em_message_store(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);
    if (ap->ops->em_store && (ap->flags & ATA_FLAG_EM))
        return ap->ops->em_store(ap, buf, count);
    return -EINVAL;
}

static ssize_t
ata_scsi_em_message_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);

    if (ap->ops->em_show && (ap->flags & ATA_FLAG_EM))
        return ap->ops->em_show(ap, buf);
    return -EINVAL;
}
DEVICE_ATTR(em_message, S_IRUGO | S_IWUSR,
        ata_scsi_em_message_show, ata_scsi_em_message_store);
EXPORT_SYMBOL_GPL(dev_attr_em_message);

static ssize_t
ata_scsi_em_message_type_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);

    return snprintf(buf, 23, "%d\n", ap->em_message_type);
}
DEVICE_ATTR(em_message_type, S_IRUGO,
          ata_scsi_em_message_type_show, NULL);
EXPORT_SYMBOL_GPL(dev_attr_em_message_type);

static ssize_t
ata_scsi_activity_show(struct device *dev, struct device_attribute *attr,
        char *buf)
{
    struct scsi_device *sdev = to_scsi_device(dev);
    struct ata_port *ap = ata_shost_to_port(sdev->host);
    struct ata_device *atadev = ata_scsi_find_dev(ap, sdev);

    if (ap->ops->sw_activity_show && (ap->flags & ATA_FLAG_SW_ACTIVITY))
        return ap->ops->sw_activity_show(atadev, buf);
    return -EINVAL;
}

static ssize_t
ata_scsi_activity_store(struct device *dev, struct device_attribute *attr,
    const char *buf, size_t count)
{
    struct scsi_device *sdev = to_scsi_device(dev);
    struct ata_port *ap = ata_shost_to_port(sdev->host);
    struct ata_device *atadev = ata_scsi_find_dev(ap, sdev);
    enum sw_activity val;
    int rc;

    if (ap->ops->sw_activity_store && (ap->flags & ATA_FLAG_SW_ACTIVITY)) {
        val = simple_strtoul(buf, NULL, 0);
        switch (val) {
        case OFF: case BLINK_ON: case BLINK_OFF:
            rc = ap->ops->sw_activity_store(atadev, val);
            if (!rc)
                return count;
            else
                return rc;
        }
    }
    return -EINVAL;
}
DEVICE_ATTR(sw_activity, S_IWUSR | S_IRUGO, ata_scsi_activity_show,
            ata_scsi_activity_store);
EXPORT_SYMBOL_GPL(dev_attr_sw_activity);

struct device_attribute *ata_common_sdev_attrs[] = {
    &dev_attr_unload_heads,
    NULL
};
EXPORT_SYMBOL_GPL(ata_common_sdev_attrs);

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

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;
}

void ata_scsi_unlock_native_capacity(struct scsi_device *sdev)
{
    struct ata_port *ap = ata_shost_to_port(sdev->host);
    struct ata_device *dev;
    unsigned long flags;

    spin_lock_irqsave(ap->lock, flags);

    dev = ata_scsi_find_dev(ap, sdev);
    if (dev && dev->n_sectors < dev->n_native_sectors) {
        dev->flags |= ATA_DFLAG_UNLOCK_HPA;
        dev->link->eh_info.action |= ATA_EH_RESET;
        ata_port_schedule_eh(ap);
    }

    spin_unlock_irqrestore(ap->lock, flags);
    ata_port_wait_eh(ap);
}

static int ata_get_identity(struct ata_port *ap, struct scsi_device *sdev,
                void __user *arg)
{
    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;
}

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 = ATA_SECT_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] == ATA_CMD_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, NULL);

    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;
}

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, NULL);

    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;
}

static int ata_ioc32(struct ata_port *ap)
{
    if (ap->flags & ATA_FLAG_PIO_DMA)
        return 1;
    if (ap->pflags & ATA_PFLAG_PIO32)
        return 1;
    return 0;
}

int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *scsidev,
             int cmd, void __user *arg)
{
    int val = -EINVAL, rc = -EINVAL;
    unsigned long flags;

    switch (cmd) {
    case ATA_IOC_GET_IO32:
        spin_lock_irqsave(ap->lock, flags);
        val = ata_ioc32(ap);
        spin_unlock_irqrestore(ap->lock, flags);
        if (copy_to_user(arg, &val, 1))
            return -EFAULT;
        return 0;

    case ATA_IOC_SET_IO32:
        val = (unsigned long) arg;
        rc = 0;
        spin_lock_irqsave(ap->lock, flags);
        if (ap->pflags & ATA_PFLAG_PIO32CHANGE) {
            if (val)
                ap->pflags |= ATA_PFLAG_PIO32;
            else
                ap->pflags &= ~ATA_PFLAG_PIO32;
        } else {
            if (val != ata_ioc32(ap))
                rc = -EINVAL;
        }
        spin_unlock_irqrestore(ap->lock, flags);
        return rc;

    case HDIO_GET_IDENTITY:
        return ata_get_identity(ap, 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;
}
EXPORT_SYMBOL_GPL(ata_sas_scsi_ioctl);

int ata_scsi_ioctl(struct scsi_device *scsidev, int cmd, void __user *arg)
{
    return ata_sas_scsi_ioctl(ata_shost_to_port(scsidev->host),
                scsidev, cmd, arg);
}
EXPORT_SYMBOL_GPL(ata_scsi_ioctl);

static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
                          struct scsi_cmnd *cmd)
{
    struct ata_queued_cmd *qc;

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

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

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");
        }
    }
}

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;
    }
}

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;
    sdev->no_report_opcodes = 1;
    sdev->no_write_same = 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;
}

static int atapi_drain_needed(struct request *rq)
{
    if (likely(rq->cmd_type != REQ_TYPE_BLOCK_PC))
        return 0;

    if (!blk_rq_bytes(rq) || (rq->cmd_flags & REQ_WRITE))
        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)
{
    struct request_queue *q = sdev->request_queue;

    if (!ata_id_has_unload(dev->id))
        dev->flags |= ATA_DFLAG_NO_UNLOAD;

    /* configure max sectors */
    blk_queue_max_hw_sectors(q, dev->max_sectors);

    if (dev->class == ATA_DEV_ATAPI) {
        void *buf;

        sdev->sector_size = ATA_SECT_SIZE;

        /* set DMA padding */
        blk_queue_update_dma_pad(q, ATA_DMA_PAD_SZ - 1);

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

        blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);
    } else {
        sdev->sector_size = ata_id_logical_sector_size(dev->id);
        sdev->manage_start_stop = 1;
    }

    /*
     * ata_pio_sectors() expects buffer for each sector to not cross
     * page boundary.  Enforce it by requiring buffers to be sector
     * aligned, which works iff sector_size is not larger than
     * PAGE_SIZE.  ATAPI devices also need the alignment as
     * IDENTIFY_PACKET is executed as ATA_PROT_PIO.
     */
    if (sdev->sector_size > PAGE_SIZE)
        ata_dev_warn(dev,
            "sector_size=%u > PAGE_SIZE, PIO may malfunction\n",
            sdev->sector_size);

    blk_queue_update_dma_alignment(q, sdev->sector_size - 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);
    }

    blk_queue_flush_queueable(q, false);

    dev->sdev = sdev;
    return 0;
}

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;
}

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;
}

int __ata_change_queue_depth(struct ata_port *ap, struct scsi_device *sdev,
                 int queue_depth, int reason)
{
    struct ata_device *dev;
    unsigned long flags;

    if (reason != SCSI_QDEPTH_DEFAULT)
        return -EOPNOTSUPP;

    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;
}

int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth,
                int reason)
{
    struct ata_port *ap = ata_shost_to_port(sdev->host);

    return __ata_change_queue_depth(ap, sdev, queue_depth, reason);
}

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 {
        /* Some odd clown BIOSen issue spindown on power off (ACPI S4
         * or S5) causing some drives to spin up and down again.
         */
        if ((qc->ap->flags & ATA_FLAG_NO_POWEROFF_SPINDOWN) &&
            system_state == SYSTEM_POWER_OFF)
            goto skip;

        if ((qc->ap->flags & ATA_FLAG_NO_HIBERNATE_SPINDOWN) &&
             system_entering_hibernation())
            goto skip;

        /* 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;
 skip:
    scmd->result = SAM_STAT_GOOD;
    return 1;
}


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;
}

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;
}

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;
}

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;
}

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;
}

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 (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 (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 * scmd->device->sector_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);
        }
    }

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

    qc->scsidone(cmd);

    ata_qc_free(qc);
}

static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
                  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);
    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_warn(dev, "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);
    cmd->scsi_done(cmd);
    DPRINTK("EXIT - early finish (good or error)\n");
    return 0;

err_did:
    ata_qc_free(qc);
    cmd->result = (DID_ERROR << 16);
    cmd->scsi_done(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;
}

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;
}

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);
}

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);
}

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;
}

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 */
        0x89,   /* page 0x89, ata info page */
        0xb0,   /* page 0xb0, block limits page */
        0xb1,   /* page 0xb1, block device characteristics page */
        0xb2,   /* page 0xb2, thin provisioning page */
    };

    rbuf[3] = sizeof(pages);    /* number of supported VPD pages */
    memcpy(rbuf + 4, pages, sizeof(pages));
    return 0;
}

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;
}

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;

    if (ata_id_has_wwn(args->id)) {
        /* SAT defined lu world wide name */
        /* piv=0, assoc=lu, code_set=binary, designator=NAA */
        rbuf[num + 0] = 1;
        rbuf[num + 1] = 3;
        rbuf[num + 3] = ATA_ID_WWN_LEN;
        num += 4;
        ata_id_string(args->id, (unsigned char *) rbuf + num,
                  ATA_ID_WWN, ATA_ID_WWN_LEN);
        num += ATA_ID_WWN_LEN;
    }
    rbuf[3] = num - 4;    /* page len (assume less than 256 bytes) */
    return 0;
}

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;
}

static unsigned int ata_scsiop_inq_b0(struct ata_scsi_args *args, u8 *rbuf)
{
    u16 min_io_sectors;

    rbuf[1] = 0xb0;
    rbuf[3] = 0x3c;     /* required VPD size with unmap support */

    /*
     * Optimal transfer length granularity.
     *
     * This is always one physical block, but for disks with a smaller
     * logical than physical sector size we need to figure out what the
     * latter is.
     */
    min_io_sectors = 1 << ata_id_log2_per_physical_sector(args->id);
    put_unaligned_be16(min_io_sectors, &rbuf[6]);

    /*
     * Optimal unmap granularity.
     *
     * The ATA spec doesn't even know about a granularity or alignment
     * for the TRIM command.  We can leave away most of the unmap related
     * VPD page entries, but we have specifify a granularity to signal
     * that we support some form of unmap - in thise case via WRITE SAME
     * with the unmap bit set.
     */
    if (ata_id_has_trim(args->id)) {
        put_unaligned_be64(65535 * 512 / 8, &rbuf[36]);
        put_unaligned_be32(1, &rbuf[28]);
    }

    return 0;
}

static unsigned int ata_scsiop_inq_b1(struct ata_scsi_args *args, u8 *rbuf)
{
    int form_factor = ata_id_form_factor(args->id);
    int media_rotation_rate = ata_id_rotation_rate(args->id);

    rbuf[1] = 0xb1;
    rbuf[3] = 0x3c;
    rbuf[4] = media_rotation_rate >> 8;
    rbuf[5] = media_rotation_rate;
    rbuf[7] = form_factor;

    return 0;
}

static unsigned int ata_scsiop_inq_b2(struct ata_scsi_args *args, u8 *rbuf)
{
    /* SCSI Thin Provisioning VPD page: SBC-3 rev 22 or later */
    rbuf[1] = 0xb2;
    rbuf[3] = 0x4;
    rbuf[5] = 1 << 6;   /* TPWS */

    return 0;
}

static unsigned int ata_scsiop_noop(struct ata_scsi_args *args, u8 *rbuf)
{
    VPRINTK("ENTER\n");
    return 0;
}

static void modecpy(u8 *dest, const u8 *src, int n, bool changeable)
{
    if (changeable) {
        memcpy(dest, src, 2);
        memset(dest + 2, 0, n - 2);
    } else {
        memcpy(dest, src, n);
    }
}

static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
{
    modecpy(buf, def_cache_mpage, sizeof(def_cache_mpage), changeable);
    if (changeable || ata_id_wcache_enabled(id))
        buf[2] |= (1 << 2); /* write cache enable */
    if (!changeable && !ata_id_rahead_enabled(id))
        buf[12] |= (1 << 5);    /* disable read ahead */
    return sizeof(def_cache_mpage);
}

static unsigned int ata_msense_ctl_mode(u8 *buf, bool changeable)
{
    modecpy(buf, def_control_mpage, sizeof(def_control_mpage), changeable);
    return sizeof(def_control_mpage);
}

static unsigned int ata_msense_rw_recovery(u8 *buf, bool changeable)
{
    modecpy(buf, def_rw_recovery_mpage, sizeof(def_rw_recovery_mpage),
        changeable);
    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 */
}

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 */
    case 1: /* changeable */
    case 2: /* defaults */
        break;  /* supported */
    case 3: /* saved */
        goto saving_not_supp;
    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, page_control == 1);
        break;

    case CACHE_MPAGE:
        p += ata_msense_caching(args->id, p, page_control == 1);
        break;

    case CONTROL_MPAGE:
        p += ata_msense_ctl_mode(p, page_control == 1);
        break;

    case ALL_MPAGES:
        p += ata_msense_rw_recovery(p, page_control == 1);
        p += ata_msense_caching(args->id, p, page_control == 1);
        p += ata_msense_ctl_mode(p, page_control == 1);
        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;
}

static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
{
    struct ata_device *dev = args->dev;
    u64 last_lba = dev->n_sectors - 1; /* LBA of the last block */
    u32 sector_size; /* physical sector size in bytes */
    u8 log2_per_phys;
    u16 lowest_aligned;

    sector_size = ata_id_logical_sector_size(dev->id);
    log2_per_phys = ata_id_log2_per_physical_sector(dev->id);
    lowest_aligned = ata_id_logical_sector_offset(dev->id, log2_per_phys);

    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[4] = sector_size >> (8 * 3);
        rbuf[5] = sector_size >> (8 * 2);
        rbuf[6] = sector_size >> (8 * 1);
        rbuf[7] = sector_size;
    } 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[ 8] = sector_size >> (8 * 3);
        rbuf[ 9] = sector_size >> (8 * 2);
        rbuf[10] = sector_size >> (8 * 1);
        rbuf[11] = sector_size;

        rbuf[12] = 0;
        rbuf[13] = log2_per_phys;
        rbuf[14] = (lowest_aligned >> 8) & 0x3f;
        rbuf[15] = lowest_aligned;

        if (ata_id_has_trim(args->id)) {
            rbuf[14] |= 0x80; /* TPE */

            if (ata_id_has_zero_after_trim(args->id))
                rbuf[14] |= 0x40; /* TPRZ */
        }
    }

    return 0;
}

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.
         *
         * This may happen before SCSI scan is complete.  Make
         * sure qc->dev->sdev isn't NULL before dereferencing.
         */
        if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL && qc->dev->sdev)
            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);
}
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);
}

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_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;
}

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;

    /*
     * 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;

    switch (tf->command) {
    /* READ/WRITE LONG use a non-standard sect_size */
    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);
        break;

    /* commands using reported Logical Block size (e.g. 512 or 4K) */
    case ATA_CMD_CFA_WRITE_NE:
    case ATA_CMD_CFA_TRANS_SECT:
    case ATA_CMD_CFA_WRITE_MULT_NE:
    /* XXX: case ATA_CMD_CFA_WRITE_SECTORS_WITHOUT_ERASE: */
    case ATA_CMD_READ:
    case ATA_CMD_READ_EXT:
    case ATA_CMD_READ_QUEUED:
    /* XXX: case ATA_CMD_READ_QUEUED_EXT: */
    case ATA_CMD_FPDMA_READ:
    case ATA_CMD_READ_MULTI:
    case ATA_CMD_READ_MULTI_EXT:
    case ATA_CMD_PIO_READ:
    case ATA_CMD_PIO_READ_EXT:
    case ATA_CMD_READ_STREAM_DMA_EXT:
    case ATA_CMD_READ_STREAM_EXT:
    case ATA_CMD_VERIFY:
    case ATA_CMD_VERIFY_EXT:
    case ATA_CMD_WRITE:
    case ATA_CMD_WRITE_EXT:
    case ATA_CMD_WRITE_FUA_EXT:
    case ATA_CMD_WRITE_QUEUED:
    case ATA_CMD_WRITE_QUEUED_FUA_EXT:
    case ATA_CMD_FPDMA_WRITE:
    case ATA_CMD_WRITE_MULTI:
    case ATA_CMD_WRITE_MULTI_EXT:
    case ATA_CMD_WRITE_MULTI_FUA_EXT:
    case ATA_CMD_PIO_WRITE:
    case ATA_CMD_PIO_WRITE_EXT:
    case ATA_CMD_WRITE_STREAM_DMA_EXT:
    case ATA_CMD_WRITE_STREAM_EXT:
        qc->sect_size = scmd->device->sector_size;
        break;

    /* Everything else uses 512 byte "sectors" */
    default:
        qc->sect_size = ATA_SECT_SIZE;
    }

    /*
     * Set flags so that all registers will be written, pass on
     * write indication (used for PIO/DMA setup), result TF is
     * copied back and we don't whine too much about its failure.
     */
    tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
    if (scmd->sc_data_direction == DMA_TO_DEVICE)
        tf->flags |= ATA_TFLAG_WRITE;

    qc->flags |= ATA_QCFLAG_RESULT_TF | ATA_QCFLAG_QUIET;

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

    /* 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;

    /* 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_warn(dev, "invalid multi_count %u ignored\n",
                     multi_count);
    }

    /*
     * 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;

    /*
     * 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;

    return 0;

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

static unsigned int ata_scsi_write_same_xlat(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;
    u64 block;
    u32 n_block;
    u32 size;
    void *buf;

    /* we may not issue DMA commands if no DMA mode is set */
    if (unlikely(!dev->dma_mode))
        goto invalid_fld;

    if (unlikely(scmd->cmd_len < 16))
        goto invalid_fld;
    scsi_16_lba_len(cdb, &block, &n_block);

    /* for now we only support WRITE SAME with the unmap bit set */
    if (unlikely(!(cdb[1] & 0x8)))
        goto invalid_fld;

    /*
     * WRITE SAME always has a sector sized buffer as payload, this
     * should never be a multiple entry S/G list.
     */
    if (!scsi_sg_count(scmd))
        goto invalid_fld;

    buf = page_address(sg_page(scsi_sglist(scmd)));
    size = ata_set_lba_range_entries(buf, 512, block, n_block);

    tf->protocol = ATA_PROT_DMA;
    tf->hob_feature = 0;
    tf->feature = ATA_DSM_TRIM;
    tf->hob_nsect = (size / 512) >> 8;
    tf->nsect = size / 512;
    tf->command = ATA_CMD_DSM;
    tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48 |
             ATA_TFLAG_WRITE;

    ata_qc_set_pc_nbytes(qc);

    return 0;

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

static int ata_mselect_caching(struct ata_queued_cmd *qc,
                   const u8 *buf, int len)
{
    struct ata_taskfile *tf = &qc->tf;
    struct ata_device *dev = qc->dev;
    char mpage[CACHE_MPAGE_LEN];
    u8 wce;

    /*
     * The first two bytes of def_cache_mpage are a header, so offsets
     * in mpage are off by 2 compared to buf.  Same for len.
     */

    if (len != CACHE_MPAGE_LEN - 2)
        return -EINVAL;

    wce = buf[0] & (1 << 2);

    /*
     * Check that read-only bits are not modified.
     */
    ata_msense_caching(dev->id, mpage, false);
    mpage[2] &= ~(1 << 2);
    mpage[2] |= wce;
    if (memcmp(mpage + 2, buf, CACHE_MPAGE_LEN - 2) != 0)
        return -EINVAL;

    tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
    tf->protocol = ATA_PROT_NODATA;
    tf->nsect = 0;
    tf->command = ATA_CMD_SET_FEATURES;
    tf->feature = wce ? SETFEATURES_WC_ON : SETFEATURES_WC_OFF;
    return 0;
}

static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
{
    struct scsi_cmnd *scmd = qc->scsicmd;
    const u8 *cdb = scmd->cmnd;
    const u8 *p;
    u8 pg, spg;
    unsigned six_byte, pg_len, hdr_len, bd_len;
    int len;

    VPRINTK("ENTER\n");

    six_byte = (cdb[0] == MODE_SELECT);
    if (six_byte) {
        if (scmd->cmd_len < 5)
            goto invalid_fld;

        len = cdb[4];
        hdr_len = 4;
    } else {
        if (scmd->cmd_len < 9)
            goto invalid_fld;

        len = (cdb[7] << 8) + cdb[8];
        hdr_len = 8;
    }

    /* We only support PF=1, SP=0.  */
    if ((cdb[1] & 0x11) != 0x10)
        goto invalid_fld;

    /* Test early for possible overrun.  */
    if (!scsi_sg_count(scmd) || scsi_sglist(scmd)->length < len)
        goto invalid_param_len;

    p = page_address(sg_page(scsi_sglist(scmd)));

    /* Move past header and block descriptors.  */
    if (len < hdr_len)
        goto invalid_param_len;

    if (six_byte)
        bd_len = p[3];
    else
        bd_len = (p[6] << 8) + p[7];

    len -= hdr_len;
    p += hdr_len;
    if (len < bd_len)
        goto invalid_param_len;
    if (bd_len != 0 && bd_len != 8)
        goto invalid_param;

    len -= bd_len;
    p += bd_len;
    if (len == 0)
        goto skip;

    /* Parse both possible formats for the mode page headers.  */
    pg = p[0] & 0x3f;
    if (p[0] & 0x40) {
        if (len < 4)
            goto invalid_param_len;

        spg = p[1];
        pg_len = (p[2] << 8) | p[3];
        p += 4;
        len -= 4;
    } else {
        if (len < 2)
            goto invalid_param_len;

        spg = 0;
        pg_len = p[1];
        p += 2;
        len -= 2;
    }

    /*
     * No mode subpages supported (yet) but asking for _all_
     * subpages may be valid
     */
    if (spg && (spg != ALL_SUB_MPAGES))
        goto invalid_param;
    if (pg_len > len)
        goto invalid_param_len;

    switch (pg) {
    case CACHE_MPAGE:
        if (ata_mselect_caching(qc, p, pg_len) < 0)
            goto invalid_param;
        break;

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

    /*
     * Only one page has changeable data, so we only support setting one
     * page at a time.
     */
    if (len > pg_len)
        goto invalid_param;

    return 0;

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

 invalid_param:
    /* "Invalid field in parameter list" */
    ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x26, 0x0);
    return 1;

 invalid_param_len:
    /* "Parameter list length error" */
    ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x1a, 0x0);
    return 1;

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

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 WRITE_SAME_16:
        return ata_scsi_write_same_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 MODE_SELECT:
    case MODE_SELECT_10:
        return ata_scsi_mode_select_xlat;
        break;

    case START_STOP:
        return ata_scsi_start_stop_xlat;
    }

    return NULL;
}

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,
                      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, xlat_func);
    else
        ata_scsi_simulate(dev, scmd);

    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;
    scmd->scsi_done(scmd);
    return 0;
}

int ata_scsi_queuecmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
    struct ata_port *ap;
    struct ata_device *dev;
    struct scsi_device *scsidev = cmd->device;
    int rc = 0;
    unsigned long irq_flags;

    ap = ata_shost_to_port(shost);

    spin_lock_irqsave(ap->lock, irq_flags);

    ata_scsi_dump_cdb(ap, cmd);

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

    spin_unlock_irqrestore(ap->lock, irq_flags);

    return rc;
}

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

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

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

    case INQUIRY:
        if (scsicmd[1] & 2)            /* is CmdDt set?  */
            ata_scsi_invalid_field(cmd);
        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;
        case 0xb0:
            ata_scsi_rbuf_fill(&args, ata_scsiop_inq_b0);
            break;
        case 0xb1:
            ata_scsi_rbuf_fill(&args, ata_scsiop_inq_b1);
            break;
        case 0xb2:
            ata_scsi_rbuf_fill(&args, ata_scsiop_inq_b2);
            break;
        default:
            ata_scsi_invalid_field(cmd);
            break;
        }
        break;

    case MODE_SENSE:
    case MODE_SENSE_10:
        ata_scsi_rbuf_fill(&args, ata_scsiop_mode_sense);
        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);
        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);
        cmd->scsi_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);
        break;

    /* all other commands */
    default:
        ata_scsi_set_sense(cmd, ILLEGAL_REQUEST, 0x20, 0x0);
        /* "Invalid command operation code" */
        cmd->scsi_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;

        shost->eh_noresume = 1;
        *(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_with_dma(ap->scsi_host,
                        &ap->tdev, 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;

 repeat:
    ata_for_each_link(link, ap, EDGE) {
        ata_for_each_dev(dev, link, ENABLED) {
            struct scsi_device *sdev;
            int channel = 0, id = 0;

            if (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);
                ata_acpi_bind(dev);
            } else {
                dev->sdev = NULL;
            }
        }
    }

    /* If we scanned while EH was in progress or allocation
     * failure occurred, scan would have failed silently.  Check
     * whether all devices are attached.
     */
    ata_for_each_link(link, ap, EDGE) {
        ata_for_each_dev(dev, link, ENABLED) {
            if (!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_err(ap,
                 "WARNING: synchronous SCSI scan failed without making any progress, switching to async\n");
    }

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

int ata_scsi_offline_dev(struct ata_device *dev)
{
    if (dev->sdev) {
        scsi_device_set_state(dev->sdev, SDEV_OFFLINE);
        return 1;
    }
    return 0;
}

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);

    ata_acpi_unbind(dev);

    /* 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_info(dev, "detaching (SCSI %s)\n",
                 dev_name(&sdev->sdev_gendev));

        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_for_each_dev(dev, link, ALL) {
        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);
    }
}

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);
}

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");
    mutex_lock(&ap->scsi_scan_mutex);

    /* 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);

    mutex_unlock(&ap->scsi_scan_mutex);
    DPRINTK("EXIT\n");
}

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_for_each_link(link, ap, EDGE) {
            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;
}

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;

    mutex_lock(&ap->scsi_scan_mutex);
    spin_lock_irqsave(ap->lock, flags);

    ata_for_each_link(link, ap, EDGE) {
        ata_for_each_dev(dev, link, ENABLED) {
            struct scsi_device *sdev = dev->sdev;

            if (!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);
    mutex_unlock(&ap->scsi_scan_mutex);
}

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 = &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);

int ata_sas_port_start(struct ata_port *ap)
{
    /*
     * the port is marked as frozen at allocation time, but if we don't
     * have new eh, we won't thaw it
     */
    if (!ap->ops->error_handler)
        ap->pflags &= ~ATA_PFLAG_FROZEN;
    return 0;
}
EXPORT_SYMBOL_GPL(ata_sas_port_start);

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

void ata_sas_async_probe(struct ata_port *ap)
{
    __ata_port_probe(ap);
}
EXPORT_SYMBOL_GPL(ata_sas_async_probe);

int ata_sas_sync_probe(struct ata_port *ap)
{
    return ata_port_probe(ap);
}
EXPORT_SYMBOL_GPL(ata_sas_sync_probe);


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

    if (rc)
        return rc;
    ap->print_id = atomic_inc_return(&ata_print_id);
    return 0;
}
EXPORT_SYMBOL_GPL(ata_sas_port_init);

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);

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);

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

    ata_scsi_dump_cdb(ap, cmd);

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