Logo Search packages:      
Sourcecode: linux-2.6 version File versions  Download package

libata-scsi.c

/*
 *  libata-scsi.c - helper library for ATA
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *                    Please ALWAYS copy linux-ide@vger.kernel.org
 *              on emails.
 *
 *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
 *  Copyright 2003-2004 Jeff Garzik
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from
 *  - http://www.t10.org/
 *  - http://www.t13.org/
 *
 */

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

#include "libata.h"

#define SECTOR_SIZE     512

typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, const u8 *scsicmd);

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


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


static const u8 def_rw_recovery_mpage[] = {
      RW_RECOVERY_MPAGE,
      RW_RECOVERY_MPAGE_LEN - 2,
      (1 << 7) |  /* AWRE, sat-r06 say it shall be 0 */
          (1 << 6),     /* ARRE (auto read reallocation) */
      0,          /* read retry count */
      0, 0, 0, 0,
      0,          /* write retry count */
      0, 0, 0
};

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

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

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


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

/**
 *    ata_std_bios_param - generic bios head/sector/cylinder calculator used by sd.
 *    @sdev: SCSI device for which BIOS geometry is to be determined
 *    @bdev: block device associated with @sdev
 *    @capacity: capacity of SCSI device
 *    @geom: location to which geometry will be output
 *
 *    Generic bios head/sector/cylinder calculator
 *    used by sd. Most BIOSes nowadays expect a XXX/255/16  (CHS)
 *    mapping. Some situations may arise where the disk is not
 *    bootable if this is not used.
 *
 *    LOCKING:
 *    Defined by the SCSI layer.  We don't really care.
 *
 *    RETURNS:
 *    Zero.
 */
int ata_std_bios_param(struct scsi_device *sdev, struct block_device *bdev,
                   sector_t capacity, int geom[])
{
      geom[0] = 255;
      geom[1] = 63;
      sector_div(capacity, 255*63);
      geom[2] = capacity;

      return 0;
}

/**
 *    ata_cmd_ioctl - Handler for HDIO_DRIVE_CMD ioctl
 *    @scsidev: Device to which we are issuing command
 *    @arg: User provided data for issuing command
 *
 *    LOCKING:
 *    Defined by the SCSI layer.  We don't really care.
 *
 *    RETURNS:
 *    Zero on success, negative errno on error.
 */

int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg)
{
      int rc = 0;
      u8 scsi_cmd[MAX_COMMAND_SIZE];
      u8 args[4], *argbuf = NULL;
      int argsize = 0;
      struct scsi_sense_hdr sshdr;
      enum dma_data_direction data_dir;

      if (arg == NULL)
            return -EINVAL;

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

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

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

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

      scsi_cmd[0] = ATA_16;

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

      /* Good values for timeout and retries?  Values below
         from scsi_ioctl_send_command() for default case... */
      if (scsi_execute_req(scsidev, scsi_cmd, data_dir, argbuf, argsize,
                       &sshdr, (10*HZ), 5)) {
            rc = -EIO;
            goto error;
      }

      /* Need code to retrieve data from check condition? */

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

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

      if (arg == NULL)
            return -EINVAL;

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

      memset(scsi_cmd, 0, sizeof(scsi_cmd));
      scsi_cmd[0]  = ATA_16;
      scsi_cmd[1]  = (3 << 1); /* Non-data */
      /* scsi_cmd[2] is already 0 -- no off.line, cc, 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[14] = args[0];

      /* Good values for timeout and retries?  Values below
         from scsi_ioctl_send_command() for default case... */
      if (scsi_execute_req(scsidev, scsi_cmd, DMA_NONE, NULL, 0, &sshdr,
                       (10*HZ), 5))
            rc = -EIO;

      /* Need code to retrieve data from check condition? */
      return rc;
}

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

      switch (cmd) {
      case ATA_IOC_GET_IO32:
            val = 0;
            if (copy_to_user(arg, &val, 1))
                  return -EFAULT;
            return 0;

      case ATA_IOC_SET_IO32:
            val = (unsigned long) arg;
            if (val != 0)
                  return -EINVAL;
            return 0;

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

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

      default:
            rc = -ENOTTY;
            break;
      }

      return rc;
}

/**
 *    ata_scsi_qc_new - acquire new ata_queued_cmd reference
 *    @dev: ATA device to which the new command is attached
 *    @cmd: SCSI command that originated this ATA command
 *    @done: SCSI command completion function
 *
 *    Obtain a reference to an unused ata_queued_cmd structure,
 *    which is the basic libata structure representing a single
 *    ATA command sent to the hardware.
 *
 *    If a command was available, fill in the SCSI-specific
 *    portions of the structure with information on the
 *    current command.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Command allocated, or %NULL if none available.
 */
struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
                               struct scsi_cmnd *cmd,
                               void (*done)(struct scsi_cmnd *))
{
      struct ata_queued_cmd *qc;

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

            if (cmd->use_sg) {
                  qc->__sg = (struct scatterlist *) cmd->request_buffer;
                  qc->n_elem = cmd->use_sg;
            } else {
                  qc->__sg = &qc->sgent;
                  qc->n_elem = 1;
            }
      } else {
            cmd->result = (DID_OK << 16) | (QUEUE_FULL << 1);
            done(cmd);
      }

      return qc;
}

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

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

            if (err) {
                  printk(KERN_WARNING "ata%u: error=0x%02x { ", id, err);
                  if (err & 0x04)         printk("DriveStatusError ");
                  if (err & 0x80) {
                        if (err & 0x04)   printk("BadCRC ");
                        else        printk("Sector ");
                  }
                  if (err & 0x40)         printk("UncorrectableError ");
                  if (err & 0x10)         printk("SectorIdNotFound ");
                  if (err & 0x02)         printk("TrackZeroNotFound ");
                  if (err & 0x01)         printk("AddrMarkNotFound ");
                  printk("}\n");
            }
      }
}

/**
 *    ata_scsi_device_suspend - suspend ATA device associated with sdev
 *    @sdev: the SCSI device to suspend
 *    @state: target power management state
 *
 *    Request suspend EH action on the ATA device associated with
 *    @sdev and wait for the operation to complete.
 *
 *    LOCKING:
 *    Kernel thread context (may sleep).
 *
 *    RETURNS:
 *    0 on success, -errno otherwise.
 */
int ata_scsi_device_suspend(struct scsi_device *sdev, pm_message_t state)
{
      struct ata_port *ap = ata_shost_to_port(sdev->host);
      struct ata_device *dev = ata_scsi_find_dev(ap, sdev);
      unsigned long flags;
      unsigned int action;
      int rc = 0;

      if (!dev)
            goto out;

      spin_lock_irqsave(ap->lock, flags);

      /* wait for the previous resume to complete */
      while (dev->flags & ATA_DFLAG_SUSPENDED) {
            spin_unlock_irqrestore(ap->lock, flags);
            ata_port_wait_eh(ap);
            spin_lock_irqsave(ap->lock, flags);
      }

      /* if @sdev is already detached, nothing to do */
      if (sdev->sdev_state == SDEV_OFFLINE ||
          sdev->sdev_state == SDEV_CANCEL || sdev->sdev_state == SDEV_DEL)
            goto out_unlock;

      /* request suspend */
      action = ATA_EH_SUSPEND;
      if (state.event != PM_EVENT_SUSPEND)
            action |= ATA_EH_PM_FREEZE;
      ap->eh_info.dev_action[dev->devno] |= action;
      ap->eh_info.flags |= ATA_EHI_QUIET;
      ata_port_schedule_eh(ap);

      spin_unlock_irqrestore(ap->lock, flags);

      /* wait for EH to do the job */
      ata_port_wait_eh(ap);

      spin_lock_irqsave(ap->lock, flags);

      /* If @sdev is still attached but the associated ATA device
       * isn't suspended, the operation failed.
       */
      if (sdev->sdev_state != SDEV_OFFLINE &&
          sdev->sdev_state != SDEV_CANCEL && sdev->sdev_state != SDEV_DEL &&
          !(dev->flags & ATA_DFLAG_SUSPENDED))
            rc = -EIO;

 out_unlock:
      spin_unlock_irqrestore(ap->lock, flags);
 out:
      if (rc == 0)
            sdev->sdev_gendev.power.power_state = state;
      return rc;
}

/**
 *    ata_scsi_device_resume - resume ATA device associated with sdev
 *    @sdev: the SCSI device to resume
 *
 *    Request resume EH action on the ATA device associated with
 *    @sdev and return immediately.  This enables parallel
 *    wakeup/spinup of devices.
 *
 *    LOCKING:
 *    Kernel thread context (may sleep).
 *
 *    RETURNS:
 *    0.
 */
int ata_scsi_device_resume(struct scsi_device *sdev)
{
      struct ata_port *ap = ata_shost_to_port(sdev->host);
      struct ata_device *dev = ata_scsi_find_dev(ap, sdev);
      struct ata_eh_info *ehi = &ap->eh_info;
      unsigned long flags;
      unsigned int action;

      if (!dev)
            goto out;

      spin_lock_irqsave(ap->lock, flags);

      /* if @sdev is already detached, nothing to do */
      if (sdev->sdev_state == SDEV_OFFLINE ||
          sdev->sdev_state == SDEV_CANCEL || sdev->sdev_state == SDEV_DEL)
            goto out_unlock;

      /* request resume */
      action = ATA_EH_RESUME;
      if (sdev->sdev_gendev.power.power_state.event == PM_EVENT_SUSPEND)
            __ata_ehi_hotplugged(ehi);
      else
            action |= ATA_EH_PM_FREEZE | ATA_EH_SOFTRESET;
      ehi->dev_action[dev->devno] |= action;

      /* We don't want autopsy and verbose EH messages.  Disable
       * those if we're the only device on this link.
       */
      if (ata_port_max_devices(ap) == 1)
            ehi->flags |= ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET;

      ata_port_schedule_eh(ap);

 out_unlock:
      spin_unlock_irqrestore(ap->lock, flags);
 out:
      sdev->sdev_gendev.power.power_state = PMSG_ON;
      return 0;
}

/**
 *    ata_to_sense_error - convert ATA error to SCSI error
 *    @id: ATA device number
 *    @drv_stat: value contained in ATA status register
 *    @drv_err: value contained in ATA error register
 *    @sk: the sense key we'll fill out
 *    @asc: the additional sense code we'll fill out
 *    @ascq: the additional sense code qualifier we'll fill out
 *    @verbose: be verbose
 *
 *    Converts an ATA error into a SCSI error.  Fill out pointers to
 *    SK, ASC, and ASCQ bytes for later use in fixed or descriptor
 *    format sense blocks.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */
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_ata_desc_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:
 *    spin_lock_irqsave(host_set lock)
 */
void ata_gen_ata_desc_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->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.
       * Since we only populate descriptor 0, the total
       * length is the same (fixed) length as descriptor 0.
       */
      desc[1] = sb[7] = 14;

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

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

/**
 *    ata_gen_fixed_sense - generate a SCSI fixed sense block
 *    @qc: Command that we are erroring out
 *
 *    Leverage ata_to_sense_error() to give us the codes.  Fit our
 *    LBA in here if there's room.
 *
 *    LOCKING:
 *    inherited from caller
 */
void ata_gen_fixed_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;
      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->id, tf->command, tf->feature,
                           &sb[2], &sb[12], &sb[13], verbose);
            sb[2] &= 0x0f;
      }

      sb[0] = 0x70;
      sb[7] = 0x0a;

      if (tf->flags & ATA_TFLAG_LBA48) {
            /* TODO: find solution for LBA48 descriptors */
      }

      else if (tf->flags & ATA_TFLAG_LBA) {
            /* A small (28b) LBA will fit in the 32b info field */
            sb[0] |= 0x80;          /* set valid bit */
            sb[3] = tf->device & 0x0f;
            sb[4] = tf->lbah;
            sb[5] = tf->lbam;
            sb[6] = tf->lbal;
      }

      else {
            /* TODO: C/H/S */
      }
}

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

static void ata_scsi_dev_config(struct scsi_device *sdev,
                        struct ata_device *dev)
{
      unsigned int max_sectors;

      /* TODO: 2048 is an arbitrary number, not the
       * hardware maximum.  This should be increased to
       * 65534 when Jens Axboe's patch for dynamically
       * determining max_sectors is merged.
       */
      max_sectors = ATA_MAX_SECTORS;
      if (dev->flags & ATA_DFLAG_LBA48)
            max_sectors = ATA_MAX_SECTORS_LBA48;
      if (dev->max_sectors)
            max_sectors = dev->max_sectors;

      blk_queue_max_sectors(sdev->request_queue, max_sectors);

      /*
       * SATA DMA transfers must be multiples of 4 byte, so
       * we need to pad ATAPI transfers using an extra sg.
       * Decrement max hw segments accordingly.
       */
      if (dev->class == ATA_DEV_ATAPI) {
            request_queue_t *q = sdev->request_queue;
            blk_queue_max_hw_segments(q, q->max_hw_segments - 1);
      }

      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);
      }
}

/**
 *    ata_scsi_slave_config - Set SCSI device attributes
 *    @sdev: SCSI device to examine
 *
 *    This is called before we actually start reading
 *    and writing to the device, to configure certain
 *    SCSI mid-layer behaviors.
 *
 *    LOCKING:
 *    Defined by SCSI layer.  We don't really care.
 */

int ata_scsi_slave_config(struct scsi_device *sdev)
{
      struct ata_port *ap = ata_shost_to_port(sdev->host);
      struct ata_device *dev = __ata_scsi_find_dev(ap, sdev);

      ata_scsi_sdev_config(sdev);

      blk_queue_max_phys_segments(sdev->request_queue, LIBATA_MAX_PRD);

      if (dev)
            ata_scsi_dev_config(sdev, dev);

      return 0;   /* scsi layer doesn't check return value, sigh */
}

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

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

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

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

      max_depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
      max_depth = min(ATA_MAX_QUEUE - 1, max_depth);
      if (queue_depth > max_depth)
            queue_depth = max_depth;

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

/**
 *    ata_scsi_start_stop_xlat - Translate SCSI START STOP UNIT command
 *    @qc: Storage for translated ATA taskfile
 *    @scsicmd: SCSI command to translate
 *
 *    Sets up an ATA taskfile to issue STANDBY (to stop) or READ VERIFY
 *    (to start). Perhaps these commands should be preceded by
 *    CHECK POWER MODE to see what power mode the device is already in.
 *    [See SAT revision 5 at www.t10.org]
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_start_stop_xlat(struct ata_queued_cmd *qc,
                                   const u8 *scsicmd)
{
      struct ata_taskfile *tf = &qc->tf;

      tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
      tf->protocol = ATA_PROT_NODATA;
      if (scsicmd[1] & 0x1) {
            ;     /* ignore IMMED bit, violates sat-r05 */
      }
      if (scsicmd[4] & 0x2)
            goto invalid_fld;       /* LOEJ bit set not supported */
      if (((scsicmd[4] >> 4) & 0xf) != 0)
            goto invalid_fld;       /* power conditions not supported */
      if (scsicmd[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 {
            tf->nsect = 0;    /* time period value (0 implies now) */
            tf->command = ATA_CMD_STANDBY;
            /* Consider: ATA STANDBY IMMEDIATE command */
      }
      /*
       * 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(qc->scsicmd, ILLEGAL_REQUEST, 0x24, 0x0);
      /* "Invalid field in cbd" */
      return 1;
}


/**
 *    ata_scsi_flush_xlat - Translate SCSI SYNCHRONIZE CACHE command
 *    @qc: Storage for translated ATA taskfile
 *    @scsicmd: SCSI command to translate (ignored)
 *
 *    Sets up an ATA taskfile to issue FLUSH CACHE or
 *    FLUSH CACHE EXT.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc, const u8 *scsicmd)
{
      struct ata_taskfile *tf = &qc->tf;

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

      if ((qc->dev->flags & ATA_DFLAG_LBA48) &&
          (ata_id_has_flush_ext(qc->dev->id)))
            tf->command = ATA_CMD_FLUSH_EXT;
      else
            tf->command = ATA_CMD_FLUSH;

      return 0;
}

/**
 *    scsi_6_lba_len - Get LBA and transfer length
 *    @scsicmd: SCSI command to translate
 *
 *    Calculate LBA and transfer length for 6-byte commands.
 *
 *    RETURNS:
 *    @plba: the LBA
 *    @plen: the transfer length
 */

static void scsi_6_lba_len(const u8 *scsicmd, u64 *plba, u32 *plen)
{
      u64 lba = 0;
      u32 len = 0;

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

      lba |= ((u64)scsicmd[2]) << 8;
      lba |= ((u64)scsicmd[3]);

      len |= ((u32)scsicmd[4]);

      *plba = lba;
      *plen = len;
}

/**
 *    scsi_10_lba_len - Get LBA and transfer length
 *    @scsicmd: SCSI command to translate
 *
 *    Calculate LBA and transfer length for 10-byte commands.
 *
 *    RETURNS:
 *    @plba: the LBA
 *    @plen: the transfer length
 */

static void scsi_10_lba_len(const u8 *scsicmd, u64 *plba, u32 *plen)
{
      u64 lba = 0;
      u32 len = 0;

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

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

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

      *plba = lba;
      *plen = len;
}

/**
 *    scsi_16_lba_len - Get LBA and transfer length
 *    @scsicmd: SCSI command to translate
 *
 *    Calculate LBA and transfer length for 16-byte commands.
 *
 *    RETURNS:
 *    @plba: the LBA
 *    @plen: the transfer length
 */

static void scsi_16_lba_len(const u8 *scsicmd, u64 *plba, u32 *plen)
{
      u64 lba = 0;
      u32 len = 0;

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

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

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

      *plba = lba;
      *plen = len;
}

/**
 *    ata_scsi_verify_xlat - Translate SCSI VERIFY command into an ATA one
 *    @qc: Storage for translated ATA taskfile
 *    @scsicmd: SCSI command to translate
 *
 *    Converts SCSI VERIFY command to an ATA READ VERIFY command.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, const u8 *scsicmd)
{
      struct ata_taskfile *tf = &qc->tf;
      struct ata_device *dev = qc->dev;
      u64 dev_sectors = qc->dev->n_sectors;
      u64 block;
      u32 n_block;

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

      if (scsicmd[0] == VERIFY)
            scsi_10_lba_len(scsicmd, &block, &n_block);
      else if (scsicmd[0] == VERIFY_16)
            scsi_16_lba_len(scsicmd, &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(qc->scsicmd, ILLEGAL_REQUEST, 0x24, 0x0);
      /* "Invalid field in cbd" */
      return 1;

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

nothing_to_do:
      qc->scsicmd->result = SAM_STAT_GOOD;
      return 1;
}

/**
 *    ata_scsi_rw_xlat - Translate SCSI r/w command into an ATA one
 *    @qc: Storage for translated ATA taskfile
 *    @scsicmd: SCSI command to translate
 *
 *    Converts any of six SCSI read/write commands into the
 *    ATA counterpart, including starting sector (LBA),
 *    sector count, and taking into account the device's LBA48
 *    support.
 *
 *    Commands %READ_6, %READ_10, %READ_16, %WRITE_6, %WRITE_10, and
 *    %WRITE_16 are currently supported.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, const u8 *scsicmd)
{
      struct ata_taskfile *tf = &qc->tf;
      struct ata_device *dev = qc->dev;
      u64 block;
      u32 n_block;

      qc->flags |= ATA_QCFLAG_IO;
      tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;

      if (scsicmd[0] == WRITE_10 || scsicmd[0] == WRITE_6 ||
          scsicmd[0] == WRITE_16)
            tf->flags |= ATA_TFLAG_WRITE;

      /* Calculate the SCSI LBA, transfer length and FUA. */
      switch (scsicmd[0]) {
      case READ_10:
      case WRITE_10:
            scsi_10_lba_len(scsicmd, &block, &n_block);
            if (unlikely(scsicmd[1] & (1 << 3)))
                  tf->flags |= ATA_TFLAG_FUA;
            break;
      case READ_6:
      case WRITE_6:
            scsi_6_lba_len(scsicmd, &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:
            scsi_16_lba_len(scsicmd, &block, &n_block);
            if (unlikely(scsicmd[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;

      if ((dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ) {
            /* yay, NCQ */
            if (!lba_48_ok(block, n_block))
                  goto out_of_range;

            tf->protocol = ATA_PROT_NCQ;
            tf->flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;

            if (tf->flags & ATA_TFLAG_WRITE)
                  tf->command = ATA_CMD_FPDMA_WRITE;
            else
                  tf->command = ATA_CMD_FPDMA_READ;

            qc->nsect = n_block;

            tf->nsect = qc->tag << 3;
            tf->hob_feature = (n_block >> 8) & 0xff;
            tf->feature = n_block & 0xff;

            tf->hob_lbah = (block >> 40) & 0xff;
            tf->hob_lbam = (block >> 32) & 0xff;
            tf->hob_lbal = (block >> 24) & 0xff;
            tf->lbah = (block >> 16) & 0xff;
            tf->lbam = (block >> 8) & 0xff;
            tf->lbal = block & 0xff;

            tf->device = 1 << 6;
            if (tf->flags & ATA_TFLAG_FUA)
                  tf->device |= 1 << 7;
      } else if (dev->flags & ATA_DFLAG_LBA) {
            tf->flags |= ATA_TFLAG_LBA;

            if (lba_28_ok(block, n_block)) {
                  /* use LBA28 */
                  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->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;

            if (unlikely(ata_rwcmd_protocol(qc) < 0))
                  goto invalid_fld;

            qc->nsect = n_block;
            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;

            /* The request -may- be too large for CHS addressing. */
            if (!lba_28_ok(block, n_block))
                  goto out_of_range;

            if (unlikely(ata_rwcmd_protocol(qc) < 0))
                  goto invalid_fld;

            /* 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;

            qc->nsect = n_block;
            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(qc->scsicmd, ILLEGAL_REQUEST, 0x24, 0x0);
      /* "Invalid field in cbd" */
      return 1;

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

nothing_to_do:
      qc->scsicmd->result = SAM_STAT_GOOD;
      return 1;
}

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

      /* We snoop the SET_FEATURES - Write Cache ON/OFF command, and
       * schedule EH_REVALIDATE operation to update the IDENTIFY DEVICE
       * cache
       */
      if (!need_sense && (qc->tf.command == ATA_CMD_SET_FEATURES) &&
          ((qc->tf.feature == SETFEATURES_WC_ON) ||
           (qc->tf.feature == SETFEATURES_WC_OFF))) {
            qc->ap->eh_info.action |= ATA_EH_REVALIDATE;
            ata_port_schedule_eh(qc->ap);
      }

      /* 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_ata_desc_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_fixed_sense(qc);
            }
      }

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

      qc->scsidone(cmd);

      ata_qc_free(qc);
}

/**
 *    ata_scmd_need_defer - Check whether we need to defer scmd
 *    @dev: ATA device to which the command is addressed
 *    @is_io: Is the command IO (and thus possibly NCQ)?
 *
 *    NCQ and non-NCQ commands cannot run together.  As upper layer
 *    only knows the queue depth, we are responsible for maintaining
 *    exclusion.  This function checks whether a new command can be
 *    issued to @dev.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    1 if deferring is needed, 0 otherwise.
 */
static int ata_scmd_need_defer(struct ata_device *dev, int is_io)
{
      struct ata_port *ap = dev->ap;

      if (!(dev->flags & ATA_DFLAG_NCQ))
            return 0;

      if (is_io) {
            if (!ata_tag_valid(ap->active_tag))
                  return 0;
      } else {
            if (!ata_tag_valid(ap->active_tag) && !ap->sactive)
                  return 0;
      }
      return 1;
}

/**
 *    ata_scsi_translate - Translate then issue SCSI command to ATA device
 *    @dev: ATA device to which the command is addressed
 *    @cmd: SCSI command to execute
 *    @done: SCSI command completion function
 *    @xlat_func: Actor which translates @cmd to an ATA taskfile
 *
 *    Our ->queuecommand() function has decided that the SCSI
 *    command issued can be directly translated into an ATA
 *    command, rather than handled internally.
 *
 *    This function sets up an ata_queued_cmd structure for the
 *    SCSI command, and sends that ata_queued_cmd to the hardware.
 *
 *    The xlat_func argument (actor) returns 0 if ready to execute
 *    ATA command, else 1 to finish translation. If 1 is returned
 *    then cmd->result (and possibly cmd->sense_buffer) are assumed
 *    to be set reflecting an error condition or clean (early)
 *    termination.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    0 on success, SCSI_ML_QUEUE_DEVICE_BUSY if the command
 *    needs to be deferred.
 */
static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
                        void (*done)(struct scsi_cmnd *),
                        ata_xlat_func_t xlat_func)
{
      struct ata_queued_cmd *qc;
      u8 *scsicmd = cmd->cmnd;
      int is_io = xlat_func == ata_scsi_rw_xlat;

      VPRINTK("ENTER\n");

      if (unlikely(ata_scmd_need_defer(dev, is_io)))
            goto defer;

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

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

            if (cmd->use_sg)
                  ata_sg_init(qc, cmd->request_buffer, cmd->use_sg);
            else
                  ata_sg_init_one(qc, cmd->request_buffer,
                              cmd->request_bufflen);

            qc->dma_dir = cmd->sc_data_direction;
      }

      qc->complete_fn = ata_scsi_qc_complete;

      if (xlat_func(qc, scsicmd))
            goto early_finish;

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

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

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

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

defer:
      DPRINTK("EXIT - defer\n");
      return SCSI_MLQUEUE_DEVICE_BUSY;
}

/**
 *    ata_scsi_rbuf_get - Map response buffer.
 *    @cmd: SCSI command containing buffer to be mapped.
 *    @buf_out: Pointer to mapped area.
 *
 *    Maps buffer contained within SCSI command @cmd.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Length of response buffer.
 */

static unsigned int ata_scsi_rbuf_get(struct scsi_cmnd *cmd, u8 **buf_out)
{
      u8 *buf;
      unsigned int buflen;

      if (cmd->use_sg) {
            struct scatterlist *sg;

            sg = (struct scatterlist *) cmd->request_buffer;
            buf = kmap_atomic(sg->page, KM_USER0) + sg->offset;
            buflen = sg->length;
      } else {
            buf = cmd->request_buffer;
            buflen = cmd->request_bufflen;
      }

      *buf_out = buf;
      return buflen;
}

/**
 *    ata_scsi_rbuf_put - Unmap response buffer.
 *    @cmd: SCSI command containing buffer to be unmapped.
 *    @buf: buffer to unmap
 *
 *    Unmaps response buffer contained within @cmd.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, u8 *buf)
{
      if (cmd->use_sg) {
            struct scatterlist *sg;

            sg = (struct scatterlist *) cmd->request_buffer;
            kunmap_atomic(buf - sg->offset, KM_USER0);
      }
}

/**
 *    ata_scsi_rbuf_fill - wrapper for SCSI command simulators
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @actor: Callback hook for desired SCSI command simulator
 *
 *    Takes care of the hard work of simulating a SCSI command...
 *    Mapping the response buffer, calling the command's handler,
 *    and handling the handler's return value.  This return value
 *    indicates whether the handler wishes the SCSI command to be
 *    completed successfully (0), or not (in which case cmd->result
 *    and sense buffer are assumed to be set).
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
                    unsigned int (*actor) (struct ata_scsi_args *args,
                                 u8 *rbuf, unsigned int buflen))
{
      u8 *rbuf;
      unsigned int buflen, rc;
      struct scsi_cmnd *cmd = args->cmd;

      buflen = ata_scsi_rbuf_get(cmd, &rbuf);
      memset(rbuf, 0, buflen);
      rc = actor(args, rbuf, buflen);
      ata_scsi_rbuf_put(cmd, rbuf);

      if (rc == 0)
            cmd->result = SAM_STAT_GOOD;
      args->done(cmd);
}

/**
 *    ata_scsiop_inq_std - Simulate INQUIRY command
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Returns standard device identification data associated
 *    with non-VPD INQUIRY command output.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
                         unsigned int buflen)
{
      u8 hdr[] = {
            TYPE_DISK,
            0,
            0x5,  /* claim SPC-3 version compatibility */
            2,
            95 - 4
      };

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

      VPRINTK("ENTER\n");

      memcpy(rbuf, hdr, sizeof(hdr));

      if (buflen > 35) {
            memcpy(&rbuf[8], "ATA     ", 8);
            ata_id_string(args->id, &rbuf[16], ATA_ID_PROD_OFS, 16);
            ata_id_string(args->id, &rbuf[32], ATA_ID_FW_REV_OFS, 4);
            if (rbuf[32] == 0 || rbuf[32] == ' ')
                  memcpy(&rbuf[32], "n/a ", 4);
      }

      if (buflen > 63) {
            const u8 versions[] = {
                  0x60, /* SAM-3 (no version claimed) */

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

                  0x02,
                  0x60  /* SPC-3 (no version claimed) */
            };

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

      return 0;
}

/**
 *    ata_scsiop_inq_00 - Simulate INQUIRY VPD page 0, list of pages
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Returns list of inquiry VPD pages available.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_00(struct ata_scsi_args *args, u8 *rbuf,
                        unsigned int buflen)
{
      const u8 pages[] = {
            0x00, /* page 0x00, this page */
            0x80, /* page 0x80, unit serial no page */
            0x83  /* page 0x83, device ident page */
      };
      rbuf[3] = sizeof(pages);      /* number of supported VPD pages */

      if (buflen > 6)
            memcpy(rbuf + 4, pages, sizeof(pages));

      return 0;
}

/**
 *    ata_scsiop_inq_80 - Simulate INQUIRY VPD page 80, device serial number
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Returns ATA device serial number.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_80(struct ata_scsi_args *args, u8 *rbuf,
                        unsigned int buflen)
{
      const u8 hdr[] = {
            0,
            0x80,             /* this page code */
            0,
            ATA_SERNO_LEN,          /* page len */
      };
      memcpy(rbuf, hdr, sizeof(hdr));

      if (buflen > (ATA_SERNO_LEN + 4 - 1))
            ata_id_string(args->id, (unsigned char *) &rbuf[4],
                        ATA_ID_SERNO_OFS, ATA_SERNO_LEN);

      return 0;
}

/**
 *    ata_scsiop_inq_83 - Simulate INQUIRY VPD page 83, device identity
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Yields two logical unit device identification designators:
 *     - vendor specific ASCII containing the ATA serial number
 *     - SAT defined "t10 vendor id based" containing ASCII vendor
 *       name ("ATA     "), model and serial numbers.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf,
                        unsigned int buflen)
{
      int num;
      const int sat_model_serial_desc_len = 68;
      const int ata_model_byte_len = 40;

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

      if (buflen > (ATA_SERNO_LEN + num + 3)) {
            /* piv=0, assoc=lu, code_set=ACSII, designator=vendor */
            rbuf[num + 0] = 2;
            rbuf[num + 3] = ATA_SERNO_LEN;
            num += 4;
            ata_id_string(args->id, (unsigned char *) rbuf + num,
                        ATA_ID_SERNO_OFS, ATA_SERNO_LEN);
            num += ATA_SERNO_LEN;
      }
      if (buflen > (sat_model_serial_desc_len + num + 3)) {
            /* 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_OFS, ata_model_byte_len);
            num += ata_model_byte_len;
            ata_id_string(args->id, (unsigned char *) rbuf + num,
                        ATA_ID_SERNO_OFS, ATA_SERNO_LEN);
            num += ATA_SERNO_LEN;
      }
      rbuf[3] = num - 4;    /* page len (assume less than 256 bytes) */
      return 0;
}

/**
 *    ata_scsiop_noop - Command handler that simply returns success.
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    No operation.  Simply returns success to caller, to indicate
 *    that the caller should successfully complete this SCSI command.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

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

/**
 *    ata_msense_push - Push data onto MODE SENSE data output buffer
 *    @ptr_io: (input/output) Location to store more output data
 *    @last: End of output data buffer
 *    @buf: Pointer to BLOB being added to output buffer
 *    @buflen: Length of BLOB
 *
 *    Store MODE SENSE data on an output buffer.
 *
 *    LOCKING:
 *    None.
 */

static void ata_msense_push(u8 **ptr_io, const u8 *last,
                      const u8 *buf, unsigned int buflen)
{
      u8 *ptr = *ptr_io;

      if ((ptr + buflen - 1) > last)
            return;

      memcpy(ptr, buf, buflen);

      ptr += buflen;

      *ptr_io = ptr;
}

/**
 *    ata_msense_caching - Simulate MODE SENSE caching info page
 *    @id: device IDENTIFY data
 *    @ptr_io: (input/output) Location to store more output data
 *    @last: End of output data buffer
 *
 *    Generate a caching info page, which conditionally indicates
 *    write caching to the SCSI layer, depending on device
 *    capabilities.
 *
 *    LOCKING:
 *    None.
 */

static unsigned int ata_msense_caching(u16 *id, u8 **ptr_io,
                               const u8 *last)
{
      u8 page[CACHE_MPAGE_LEN];

      memcpy(page, def_cache_mpage, sizeof(page));
      if (ata_id_wcache_enabled(id))
            page[2] |= (1 << 2);    /* write cache enable */
      if (!ata_id_rahead_enabled(id))
            page[12] |= (1 << 5);   /* disable read ahead */

      ata_msense_push(ptr_io, last, page, sizeof(page));
      return sizeof(page);
}

/**
 *    ata_msense_ctl_mode - Simulate MODE SENSE control mode page
 *    @dev: Device associated with this MODE SENSE command
 *    @ptr_io: (input/output) Location to store more output data
 *    @last: End of output data buffer
 *
 *    Generate a generic MODE SENSE control mode page.
 *
 *    LOCKING:
 *    None.
 */

static unsigned int ata_msense_ctl_mode(u8 **ptr_io, const u8 *last)
{
      ata_msense_push(ptr_io, last, def_control_mpage,
                  sizeof(def_control_mpage));
      return sizeof(def_control_mpage);
}

/**
 *    ata_msense_rw_recovery - Simulate MODE SENSE r/w error recovery page
 *    @dev: Device associated with this MODE SENSE command
 *    @ptr_io: (input/output) Location to store more output data
 *    @last: End of output data buffer
 *
 *    Generate a generic MODE SENSE r/w error recovery page.
 *
 *    LOCKING:
 *    None.
 */

static unsigned int ata_msense_rw_recovery(u8 **ptr_io, const u8 *last)
{

      ata_msense_push(ptr_io, last, def_rw_recovery_mpage,
                  sizeof(def_rw_recovery_mpage));
      return sizeof(def_rw_recovery_mpage);
}

/*
 * We can turn this into a real blacklist if it's needed, for now just
 * blacklist any Maxtor BANC1G10 revision firmware
 */
static int ata_dev_supports_fua(u16 *id)
{
      unsigned char model[41], fw[9];

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

      ata_id_c_string(id, model, ATA_ID_PROD_OFS, sizeof(model));
      ata_id_c_string(id, fw, ATA_ID_FW_REV_OFS, sizeof(fw));

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

      return 0; /* blacklisted */
}

/**
 *    ata_scsiop_mode_sense - Simulate MODE SENSE 6, 10 commands
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Simulate MODE SENSE commands. Assume this is invoked for direct
 *    access devices (e.g. disks) only. There should be no block
 *    descriptor for other device types.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf,
                          unsigned int buflen)
{
      struct ata_device *dev = args->dev;
      u8 *scsicmd = args->cmd->cmnd, *p, *last;
      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, output_len, alloc_len, minlen;
      u8 dpofua;

      VPRINTK("ENTER\n");

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

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

      if (six_byte) {
            output_len = 4 + (ebd ? 8 : 0);
            alloc_len = scsicmd[4];
      } else {
            output_len = 8 + (ebd ? 8 : 0);
            alloc_len = (scsicmd[7] << 8) + scsicmd[8];
      }
      minlen = (alloc_len < buflen) ? alloc_len : buflen;

      p = rbuf + output_len;
      last = rbuf + minlen - 1;

      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:
            output_len += ata_msense_rw_recovery(&p, last);
            break;

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

      case CONTROL_MPAGE: {
            output_len += ata_msense_ctl_mode(&p, last);
            break;
            }

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

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

      if (minlen < 1)
            return 0;

      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) {
            output_len--;
            rbuf[0] = output_len;
            if (minlen > 2)
                  rbuf[2] |= dpofua;
            if (ebd) {
                  if (minlen > 3)
                        rbuf[3] = sizeof(sat_blk_desc);
                  if (minlen > 11)
                        memcpy(rbuf + 4, sat_blk_desc,
                               sizeof(sat_blk_desc));
            }
      } else {
            output_len -= 2;
            rbuf[0] = output_len >> 8;
            if (minlen > 1)
                  rbuf[1] = output_len;
            if (minlen > 3)
                  rbuf[3] |= dpofua;
            if (ebd) {
                  if (minlen > 7)
                        rbuf[7] = sizeof(sat_blk_desc);
                  if (minlen > 15)
                        memcpy(rbuf + 8, sat_blk_desc,
                               sizeof(sat_blk_desc));
            }
      }
      return 0;

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

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

/**
 *    ata_scsiop_read_cap - Simulate READ CAPACITY[ 16] commands
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Simulate READ CAPACITY commands.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf,
                          unsigned int buflen)
{
      u64 n_sectors;
      u32 tmp;

      VPRINTK("ENTER\n");

      if (ata_id_has_lba(args->id)) {
            if (ata_id_has_lba48(args->id))
                  n_sectors = ata_id_u64(args->id, 100);
            else
                  n_sectors = ata_id_u32(args->id, 60);
      } else {
            /* CHS default translation */
            n_sectors = args->id[1] * args->id[3] * args->id[6];

            if (ata_id_current_chs_valid(args->id))
                  /* CHS current translation */
                  n_sectors = ata_id_u32(args->id, 57);
      }

      n_sectors--;            /* ATA TotalUserSectors - 1 */

      if (args->cmd->cmnd[0] == READ_CAPACITY) {
            if( n_sectors >= 0xffffffffULL )
                  tmp = 0xffffffff ;  /* Return max count on overflow */
            else
                  tmp = n_sectors ;

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

            /* sector size */
            tmp = ATA_SECT_SIZE;
            rbuf[6] = tmp >> 8;
            rbuf[7] = tmp;

      } else {
            /* sector count, 64-bit */
            tmp = n_sectors >> (8 * 4);
            rbuf[2] = tmp >> (8 * 3);
            rbuf[3] = tmp >> (8 * 2);
            rbuf[4] = tmp >> (8 * 1);
            rbuf[5] = tmp;
            tmp = n_sectors;
            rbuf[6] = tmp >> (8 * 3);
            rbuf[7] = tmp >> (8 * 2);
            rbuf[8] = tmp >> (8 * 1);
            rbuf[9] = tmp;

            /* sector size */
            tmp = ATA_SECT_SIZE;
            rbuf[12] = tmp >> 8;
            rbuf[13] = tmp;
      }

      return 0;
}

/**
 *    ata_scsiop_report_luns - Simulate REPORT LUNS command
 *    @args: device IDENTIFY data / SCSI command of interest.
 *    @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *    @buflen: Response buffer length.
 *
 *    Simulate REPORT LUNS command.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_report_luns(struct ata_scsi_args *args, u8 *rbuf,
                           unsigned int buflen)
{
      VPRINTK("ENTER\n");
      rbuf[3] = 8;      /* just one lun, LUN 0, size 8 bytes */

      return 0;
}

/**
 *    ata_scsi_set_sense - Set SCSI sense data and status
 *    @cmd: SCSI request to be handled
 *    @sk: SCSI-defined sense key
 *    @asc: SCSI-defined additional sense code
 *    @ascq: SCSI-defined additional sense code qualifier
 *
 *    Helper function that builds a valid fixed format, current
 *    response code and the given sense key (sk), additional sense
 *    code (asc) and additional sense code qualifier (ascq) with
 *    a SCSI command status of %SAM_STAT_CHECK_CONDITION and
 *    DRIVER_SENSE set in the upper bits of scsi_cmnd::result .
 *
 *    LOCKING:
 *    Not required
 */

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

      cmd->sense_buffer[0] = 0x70;  /* fixed format, current */
      cmd->sense_buffer[2] = sk;
      cmd->sense_buffer[7] = 18 - 8;      /* additional sense length */
      cmd->sense_buffer[12] = asc;
      cmd->sense_buffer[13] = ascq;
}

/**
 *    ata_scsi_badcmd - End a SCSI request with an error
 *    @cmd: SCSI request to be handled
 *    @done: SCSI command completion function
 *    @asc: SCSI-defined additional sense code
 *    @ascq: SCSI-defined additional sense code qualifier
 *
 *    Helper function that completes a SCSI command with
 *    %SAM_STAT_CHECK_CONDITION, with a sense key %ILLEGAL_REQUEST
 *    and the specified additional sense codes.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

void ata_scsi_badcmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *), u8 asc, u8 ascq)
{
      DPRINTK("ENTER\n");
      ata_scsi_set_sense(cmd, ILLEGAL_REQUEST, asc, ascq);

      done(cmd);
}

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_ata_desc_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, sizeof(cmd->sense_buffer));

      ap->ops->tf_read(ap, &qc->tf);

      /* 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);

      ata_sg_init_one(qc, cmd->sense_buffer, sizeof(cmd->sense_buffer));
      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 = ATA_PROT_ATAPI_DMA;
            qc->tf.feature |= ATAPI_PKT_DMA;
      } else {
            qc->tf.protocol = ATA_PROT_ATAPI;
            qc->tf.lbam = (8 * 1024) & 0xff;
            qc->tf.lbah = (8 * 1024) >> 8;
      }
      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_ata_desc_sense(qc);
            }

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

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

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

            if ((scsicmd[0] == INQUIRY) && ((scsicmd[1] & 0x03) == 0)) {
                  u8 *buf = NULL;
                  unsigned int buflen;

                  buflen = ata_scsi_rbuf_get(cmd, &buf);

      /* 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, buf);
            }

            cmd->result = SAM_STAT_GOOD;
      }

      qc->scsidone(cmd);
      ata_qc_free(qc);
}
/**
 *    atapi_xlat - Initialize PACKET taskfile
 *    @qc: command structure to be initialized
 *    @scsicmd: SCSI CDB associated with this PACKET command
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Zero on success, non-zero on failure.
 */

static unsigned int atapi_xlat(struct ata_queued_cmd *qc, const u8 *scsicmd)
{
      struct scsi_cmnd *cmd = qc->scsicmd;
      struct ata_device *dev = qc->dev;
      int using_pio = (dev->flags & ATA_DFLAG_PIO);
      int nodata = (cmd->sc_data_direction == DMA_NONE);

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

      memcpy(&qc->cdb, scsicmd, dev->cdb_len);

      qc->complete_fn = atapi_qc_complete;

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

      qc->tf.command = ATA_CMD_PACKET;

      /* no data, or PIO data xfer */
      if (using_pio || nodata) {
            if (nodata)
                  qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
            else
                  qc->tf.protocol = ATA_PROT_ATAPI;
            qc->tf.lbam = (8 * 1024) & 0xff;
            qc->tf.lbah = (8 * 1024) >> 8;
      }

      /* DMA data xfer */
      else {
            qc->tf.protocol = ATA_PROT_ATAPI_DMA;
            qc->tf.feature |= ATAPI_PKT_DMA;

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

      qc->nbytes = cmd->request_bufflen;

      return 0;
}

static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
{
      if (likely(id < ATA_MAX_DEVICES))
            return &ap->device[id];
      return NULL;
}

static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
                              const struct scsi_device *scsidev)
{
      /* skip commands not addressed to targets we simulate */
      if (unlikely(scsidev->channel || scsidev->lun))
            return NULL;

      return ata_find_dev(ap, scsidev->id);
}

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

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

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

      return 1;
}

/**
 *    ata_scsi_find_dev - lookup ata_device from scsi_cmnd
 *    @ap: ATA port to which the device is attached
 *    @scsidev: SCSI device from which we derive the ATA device
 *
 *    Given various information provided in struct scsi_cmnd,
 *    map that onto an ATA bus, and using that mapping
 *    determine which ata_device is associated with the
 *    SCSI command to be sent.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 *
 *    RETURNS:
 *    Associated ATA device, or %NULL if not found.
 */
static struct ata_device *
ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
{
      struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);

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

      return dev;
}

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

            case 6:           /* DMA */
                  return ATA_PROT_DMA;

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

            case 10:    /* Device Reset */
            case 0:           /* Hard Reset */
            case 1:           /* SRST */
            case 2:           /* Bus Idle */
            case 7:           /* Packet */
            case 8:           /* DMA Queued */
            case 9:           /* Device Diagnostic */
            case 11:    /* UDMA Data-in */
            case 12:    /* UDMA Data-Out */
            case 13:    /* FPDMA */
            default:    /* Reserved */
                  break;
      }

      return ATA_PROT_UNKNOWN;
}

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

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

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

      if (scsicmd[1] & 0xe0)
            /* PIO multi not supported yet */
            goto invalid_fld;

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

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

            tf->feature = scsicmd[3];
            tf->nsect = scsicmd[4];
            tf->lbal = scsicmd[5];
            tf->lbam = scsicmd[6];
            tf->lbah = scsicmd[7];
            tf->device = scsicmd[8];
            tf->command = scsicmd[9];
      }
      /*
       * If slave is possible, enforce correct master/slave bit
      */
      if (qc->ap->flags & ATA_FLAG_SLAVE_POSS)
            tf->device = qc->dev->devno ?
                  tf->device | ATA_DEV1 : tf->device & ~ATA_DEV1;

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

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

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

      /*
       * Set transfer length.
       *
       * TODO: find out if we need to do more here to
       *       cover scatter/gather case.
       */
      qc->nsect = cmd->request_bufflen / ATA_SECT_SIZE;

      /* request result TF */
      qc->flags |= ATA_QCFLAG_RESULT_TF;

      return 0;

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

/**
 *    ata_get_xlat_func - check if SCSI to ATA translation is possible
 *    @dev: ATA device
 *    @cmd: SCSI command opcode to consider
 *
 *    Look up the SCSI command given, and determine whether the
 *    SCSI command is to be translated or simulated.
 *
 *    RETURNS:
 *    Pointer to translation function if possible, %NULL if not.
 */

static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
{
      switch (cmd) {
      case READ_6:
      case READ_10:
      case READ_16:

      case WRITE_6:
      case WRITE_10:
      case WRITE_16:
            return ata_scsi_rw_xlat;

      case SYNCHRONIZE_CACHE:
            if (ata_try_flush_cache(dev))
                  return ata_scsi_flush_xlat;
            break;

      case VERIFY:
      case VERIFY_16:
            return ata_scsi_verify_xlat;

      case ATA_12:
      case ATA_16:
            return ata_scsi_pass_thru;

      case START_STOP:
            return ata_scsi_start_stop_xlat;
      }

      return NULL;
}

/**
 *    ata_scsi_dump_cdb - dump SCSI command contents to dmesg
 *    @ap: ATA port to which the command was being sent
 *    @cmd: SCSI command to dump
 *
 *    Prints the contents of a SCSI command via printk().
 */

static inline void ata_scsi_dump_cdb(struct ata_port *ap,
                             struct scsi_cmnd *cmd)
{
#ifdef ATA_DEBUG
      struct scsi_device *scsidev = cmd->device;
      u8 *scsicmd = cmd->cmnd;

      DPRINTK("CDB (%u:%d,%d,%d) %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
            ap->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 *cmd,
                              void (*done)(struct scsi_cmnd *),
                              struct ata_device *dev)
{
      int rc = 0;

      if (dev->class == ATA_DEV_ATA) {
            ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
                                                cmd->cmnd[0]);

            if (xlat_func)
                  rc = ata_scsi_translate(dev, cmd, done, xlat_func);
            else
                  ata_scsi_simulate(dev, cmd, done);
      } else
            rc = ata_scsi_translate(dev, cmd, done, atapi_xlat);

      return rc;
}

/**
 *    ata_scsi_queuecmd - Issue SCSI cdb to libata-managed device
 *    @cmd: SCSI command to be sent
 *    @done: Completion function, called when command is complete
 *
 *    In some cases, this function translates SCSI commands into
 *    ATA taskfiles, and queues the taskfiles to be sent to
 *    hardware.  In other cases, this function simulates a
 *    SCSI device by evaluating and responding to certain
 *    SCSI commands.  This creates the overall effect of
 *    ATA and ATAPI devices appearing as SCSI devices.
 *
 *    LOCKING:
 *    Releases scsi-layer-held lock, and obtains host_set lock.
 *
 *    RETURNS:
 *    Return value from __ata_scsi_queuecmd() if @cmd can be queued,
 *    0 otherwise.
 */
int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
      struct ata_port *ap;
      struct ata_device *dev;
      struct scsi_device *scsidev = cmd->device;
      struct Scsi_Host *shost = scsidev->host;
      int rc = 0;

      ap = ata_shost_to_port(shost);

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

      ata_scsi_dump_cdb(ap, cmd);

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

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

/**
 *    ata_scsi_simulate - simulate SCSI command on ATA device
 *    @dev: the target device
 *    @cmd: SCSI command being sent to device.
 *    @done: SCSI command completion function.
 *
 *    Interprets and directly executes a select list of SCSI commands
 *    that can be handled internally.
 *
 *    LOCKING:
 *    spin_lock_irqsave(host_set lock)
 */

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

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

      switch(scsicmd[0]) {
            /* no-op's, complete with success */
            case SYNCHRONIZE_CACHE:
            case REZERO_UNIT:
            case SEEK_6:
            case SEEK_10:
            case TEST_UNIT_READY:
            case FORMAT_UNIT:       /* FIXME: correct? */
            case SEND_DIAGNOSTIC:         /* FIXME: correct? */
                  ata_scsi_rbuf_fill(&args, ata_scsiop_noop);
                  break;

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

            case MODE_SENSE:
            case MODE_SENSE_10:
                  ata_scsi_rbuf_fill(&args, ata_scsiop_mode_sense);
                  break;

            case MODE_SELECT: /* unconditionally return */
            case MODE_SELECT_10:    /* bad-field-in-cdb */
                  ata_scsi_invalid_field(cmd, done);
                  break;

            case READ_CAPACITY:
                  ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
                  break;

            case SERVICE_ACTION_IN:
                  if ((scsicmd[1] & 0x1f) == SAI_READ_CAPACITY_16)
                        ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
                  else
                        ata_scsi_invalid_field(cmd, done);
                  break;

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

            /* mandatory commands we haven't implemented yet */
            case REQUEST_SENSE:

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

void ata_scsi_scan_host(struct ata_port *ap)
{
      unsigned int i;

      if (ap->flags & ATA_FLAG_DISABLED)
            return;

      for (i = 0; i < ATA_MAX_DEVICES; i++) {
            struct ata_device *dev = &ap->device[i];
            struct scsi_device *sdev;

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

            sdev = __scsi_add_device(ap->host, 0, i, 0, NULL);
            if (!IS_ERR(sdev)) {
                  dev->sdev = sdev;
                  scsi_device_put(sdev);
            }
      }
}

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

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

      /* clearing dev->sdev is protected by host_set 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_set 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->host->scan_mutex);

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

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

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

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

      DPRINTK("ENTER\n");

      /* unplug detached devices */
      for (i = 0; i < ATA_MAX_DEVICES; i++) {
            struct ata_device *dev = &ap->device[i];
            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);
      }

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

      /* If we scanned while EH was in progress, scan would have
       * failed silently.  Requeue if there are enabled but
       * unattached devices.
       */
      for (i = 0; i < ATA_MAX_DEVICES; i++) {
            struct ata_device *dev = &ap->device[i];
            if (ata_dev_enabled(dev) && !dev->sdev) {
                  queue_delayed_work(ata_aux_wq, &ap->hotplug_task, HZ);
                  break;
            }
      }

      DPRINTK("EXIT\n");
}

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

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

      if ((channel != SCAN_WILD_CARD && channel != 0) ||
          (lun != SCAN_WILD_CARD && lun != 0))
            return -EINVAL;

      spin_lock_irqsave(ap->lock, flags);

      if (id == SCAN_WILD_CARD) {
            ap->eh_info.probe_mask |= (1 << ATA_MAX_DEVICES) - 1;
            ap->eh_info.action |= ATA_EH_SOFTRESET;
      } else {
            struct ata_device *dev = ata_find_dev(ap, id);

            if (dev) {
                  ap->eh_info.probe_mask |= 1 << dev->devno;
                  ap->eh_info.action |= ATA_EH_SOFTRESET;
                  ap->eh_info.flags |= ATA_EHI_RESUME_LINK;
            } else
                  rc = -EINVAL;
      }

      if (rc == 0)
            ata_port_schedule_eh(ap);

      spin_unlock_irqrestore(ap->lock, flags);

      return rc;
}

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

      for (i = 0; i < ATA_MAX_DEVICES; i++) {
            dev = &ap->device[i];

            if (ata_dev_enabled(dev) && dev->sdev)
                  scsi_rescan_device(&(dev->sdev->sdev_gendev));
      }
}

Generated by  Doxygen 1.6.0   Back to index