[libata] ATA passthru (arbitrary ATA command execution)

Authors:
Brett Russ <russb@emc.com>
John W. Linville <linville@tuxdriver.com>
Andy Warner <andyw@pobox.com>

1 files changed, 547 insertions, 104 deletions

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 4c96df060c3b..22c77a113536 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -29,10 +29,13 @@
 #include "scsi.h"
 #include <scsi/scsi_host.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, u8 *scsicmd);
 static struct ata_device *
 ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev);
@@ -67,6 +70,148 @@ int ata_std_bios_param(struct scsi_device *sdev, struct block_device *bdev,
         return 0;
 }
 
+/**
+ *      ata_cmd_ioctl - Handler for HDIO_DRIVE_CMD ioctl
+ *      @dev: Device to whom 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_request *sreq;
+
+        if (NULL == (void *)arg)
+                return -EINVAL;
+
+        if (copy_from_user(args, arg, sizeof(args)))
+                return -EFAULT;
+
+        sreq = scsi_allocate_request(scsidev, GFP_KERNEL);
+        if (!sreq)
+                return -EINTR;
+
+        memset(scsi_cmd, 0, sizeof(scsi_cmd));
+
+        if (args[3]) {
+                argsize = SECTOR_SIZE * args[3];
+                argbuf = kmalloc(argsize, GFP_KERNEL);
+                if (argbuf == NULL)
+                        return -ENOMEM;
+
+                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 */
+                sreq->sr_data_direction = DMA_FROM_DEVICE;
+        } else {
+                scsi_cmd[1]  = (3 << 1); /* Non-data */
+                /* scsi_cmd[2] is already 0 -- no off.line, cc, or data xfer */
+                sreq->sr_data_direction = 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... */
+        scsi_wait_req(sreq, scsi_cmd, argbuf, argsize, (10*HZ), 5);
+
+        if (sreq->sr_result) {
+                rc = -EIO;
+                goto error;
+        }
+
+        /* Need code to retrieve data from check condition? */
+
+        if ((argbuf)
+         && copy_to_user((void *)(arg + sizeof(args)), argbuf, argsize))
+                rc = -EFAULT;
+error:
+        scsi_release_request(sreq);
+
+        if (argbuf)
+                kfree(argbuf);
+
+        return rc;
+}
+
+/**
+ *      ata_task_ioctl - Handler for HDIO_DRIVE_TASK ioctl
+ *      @dev: Device to whom 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_request *sreq;
+
+        if (NULL == (void *)arg)
+                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];
+
+        sreq = scsi_allocate_request(scsidev, GFP_KERNEL);
+        if (!sreq) {
+                rc = -EINTR;
+                goto error;
+        }
+
+        sreq->sr_data_direction = DMA_NONE;
+        /* Good values for timeout and retries?  Values below
+           from scsi_ioctl_send_command() for default case... */
+        scsi_wait_req(sreq, scsi_cmd, NULL, 0, (10*HZ), 5);
+
+        if (sreq->sr_result) {
+                rc = -EIO;
+                goto error;
+        }
+
+        /* Need code to retrieve data from check condition? */
+
+error:
+        scsi_release_request(sreq);
+        return rc;
+}
+
 int ata_scsi_ioctl(struct scsi_device *scsidev, int cmd, void __user *arg)
 {
         struct ata_port *ap;
@@ -96,6 +241,16 @@ int ata_scsi_ioctl(struct scsi_device *scsidev, int cmd, void __user *arg)
                         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;
@@ -154,24 +309,69 @@ struct ata_queued_cmd *ata_scsi_qc_new(struct ata_port *ap,
 }
 
 /**
+ *      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_to_sense_error - convert ATA error to SCSI error
- *      @qc: Command that we are erroring out
  *      @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
  *
- *      Converts an ATA error into a SCSI error. While we are at it
- *      we decode and dump the ATA error for the user so that they
- *      have some idea what really happened at the non make-believe
- *      layer.
+ *      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(struct ata_queued_cmd *qc, u8 drv_stat)
+void ata_to_sense_error(unsigned id, u8 drv_stat, u8 drv_err, u8 *sk, u8 *asc, 
+                        u8 *ascq)
 {
-        struct scsi_cmnd *cmd = qc->scsicmd;
-        u8 err = 0;
-        unsigned char *sb = cmd->sense_buffer;
+        int i;
         /* Based on the 3ware driver translation table */
         static unsigned char sense_table[][4] = {
                 /* BBD|ECC|ID|MAR */
@@ -212,105 +412,183 @@ void ata_to_sense_error(struct ata_queued_cmd *qc, u8 drv_stat)
                 {0x04,          RECOVERED_ERROR, 0x11, 0x00},   // Recovered ECC error    Medium error, recovered
                 {0xFF, 0xFF, 0xFF, 0xFF}, // END mark
         };
-        int i = 0;
-
-        cmd->result = SAM_STAT_CHECK_CONDITION;
 
         /*
          *      Is this an error we can process/parse
          */
-
-        if(drv_stat & ATA_ERR)
-                /* Read the err bits */
-                err = ata_chk_err(qc->ap);
-
-        /* Display the ATA level error info */
-
-        printk(KERN_WARNING "ata%u: status=0x%02x { ", qc->ap->id, drv_stat);
-        if(drv_stat & 0x80)
-        {
-                printk("Busy ");
-                err = 0;        /* Data is not valid in this case */
+        if (drv_stat & ATA_BUSY) {
+                drv_err = 0;    /* Ignore the err bits, they're invalid */
         }
-        else {
-                if(drv_stat & 0x40)     printk("DriveReady ");
-                if(drv_stat & 0x20)     printk("DeviceFault ");
-                if(drv_stat & 0x10)     printk("SeekComplete ");
-                if(drv_stat & 0x08)     printk("DataRequest ");
-                if(drv_stat & 0x04)     printk("CorrectedError ");
-                if(drv_stat & 0x02)     printk("Index ");
-                if(drv_stat & 0x01)     printk("Error ");
+
+        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 */
+                printk(KERN_WARNING "ata%u: no sense translation for "
+                       "error 0x%02x\n", id, drv_err);
         }
-        printk("}\n");
-
-        if(err)
-        {
-                printk(KERN_WARNING "ata%u: error=0x%02x { ", qc->ap->id, err);
-                if(err & 0x04)          printk("DriveStatusError ");
-                if(err & 0x80)
-                {
-                        if(err & 0x04)
-                                printk("BadCRC ");
-                        else
-                                printk("Sector ");
+
+        /* 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;
                 }
-                if(err & 0x40)          printk("UncorrectableError ");
-                if(err & 0x10)          printk("SectorIdNotFound ");
-                if(err & 0x02)          printk("TrackZeroNotFound ");
-                if(err & 0x01)          printk("AddrMarkNotFound ");
-                printk("}\n");
+        }
+        /* No error?  Undecoded? */
+        printk(KERN_WARNING "ata%u: no sense translation for status: 0x%02x\n", 
+               id, drv_stat);
+
+        /* For our last chance pick, use medium read error because
+         * it's much more common than an ATA drive telling you a write
+         * has failed.
+         */
+        *sk = MEDIUM_ERROR;
+        *asc = 0x11; /* "unrecovered read error" */
+        *ascq = 0x04; /*  "auto-reallocation failed" */
+
+ translate_done:
+        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->tf;
+        unsigned char *sb = cmd->sense_buffer;
+        unsigned char *desc = sb + 8;
+
+        memset(sb, 0, SCSI_SENSE_BUFFERSIZE);
+
+        cmd->result = SAM_STAT_CHECK_CONDITION;
+
+        /*
+         * Read the controller registers.
+         */
+        assert(NULL != qc->ap->ops->tf_read);
+        qc->ap->ops->tf_read(qc->ap, tf);
 
-                /* Should we dump sector info here too ?? */
+        /*
+         * Use ata_to_sense_error() to map status register bits
+         * onto sense key, asc & ascq.
+         */
+        if (unlikely(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]);
+                sb[1] &= 0x0f;
         }
 
+        /*
+         * Sense data is current and format is descriptor.
+         */
+        sb[0] = 0x72;
 
-        /* Look for err */
-        while(sense_table[i][0] != 0xFF)
-        {
-                /* Look for best matches first */
-                if((sense_table[i][0] & err) == sense_table[i][0])
-                {
-                        sb[0] = 0x70;
-                        sb[2] = sense_table[i][1];
-                        sb[7] = 0x0a;
-                        sb[12] = sense_table[i][2];
-                        sb[13] = sense_table[i][3];
-                        return;
-                }
-                i++;
+        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;
         }
-        /* No immediate match */
-        if(err)
-                printk(KERN_DEBUG "ata%u: no sense translation for 0x%02x\n", qc->ap->id, err);
+}
 
-        i = 0;
-        /* Fall back to interpreting status bits */
-        while(stat_table[i][0] != 0xFF)
-        {
-                if(stat_table[i][0] & drv_stat)
-                {
-                        sb[0] = 0x70;
-                        sb[2] = stat_table[i][1];
-                        sb[7] = 0x0a;
-                        sb[12] = stat_table[i][2];
-                        sb[13] = stat_table[i][3];
-                        return;
-                }
-                i++;
+/**
+ *      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->tf;
+        unsigned char *sb = cmd->sense_buffer;
+
+        memset(sb, 0, SCSI_SENSE_BUFFERSIZE);
+
+        cmd->result = SAM_STAT_CHECK_CONDITION;
+
+        /*
+         * Read the controller registers.
+         */
+        assert(NULL != qc->ap->ops->tf_read);
+        qc->ap->ops->tf_read(qc->ap, tf);
+
+        /*
+         * Use ata_to_sense_error() to map status register bits
+         * onto sense key, asc & ascq.
+         */
+        if (unlikely(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]);
+                sb[2] &= 0x0f;
         }
-        /* No error ?? */
-        printk(KERN_ERR "ata%u: called with no error (%02X)!\n", qc->ap->id, drv_stat);
-        /* additional-sense-code[-qualifier] */
 
         sb[0] = 0x70;
-        sb[2] = MEDIUM_ERROR;
-        sb[7] = 0x0A;
-        if (cmd->sc_data_direction == DMA_FROM_DEVICE) {
-                sb[12] = 0x11; /* "unrecovered read error" */
-                sb[13] = 0x04;
-        } else {
-                sb[12] = 0x0C; /* "write error -             */
-                sb[13] = 0x02; /*  auto-reallocation failed" */
+        sb[7] = 0x0a;
+        if (tf->flags & ATA_TFLAG_LBA && !(tf->flags & ATA_TFLAG_LBA48)) {
+                /* 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;
         }
 }
 
@@ -626,11 +904,36 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 static int ata_scsi_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
 {
         struct scsi_cmnd *cmd = qc->scsicmd;
+        int need_sense = drv_stat & (ATA_ERR | ATA_BUSY | ATA_DRQ);
+
+        /* 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 (((cmd->cmnd[0] == ATA_16) || (cmd->cmnd[0] == ATA_12)) &&
+            ((cmd->cmnd[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 (unlikely(drv_stat & (ATA_ERR | ATA_BUSY | ATA_DRQ)))
-                ata_to_sense_error(qc, drv_stat);
-        else
-                cmd->result = SAM_STAT_GOOD;
+        if (need_sense) {
+                /* The ata_gen_..._sense routines fill in tf */
+                ata_dump_status(qc->ap->id, &qc->tf);
+        }
 
         qc->scsidone(cmd);
 
@@ -671,8 +974,8 @@ static void ata_scsi_translate(struct ata_port *ap, struct ata_device *dev,
                 return;
 
         /* data is present; dma-map it */
-        if (cmd->sc_data_direction == DMA_FROM_DEVICE ||
-            cmd->sc_data_direction == DMA_TO_DEVICE) {
+        if (cmd->sc_data_direction == SCSI_DATA_READ ||
+            cmd->sc_data_direction == SCSI_DATA_WRITE) {
                 if (unlikely(cmd->request_bufflen < 1)) {
                         printk(KERN_WARNING "ata%u(%u): WARNING: zero len r/w req\n",
                                ap->id, dev->devno);
@@ -692,7 +995,6 @@ static void ata_scsi_translate(struct ata_port *ap, struct ata_device *dev,
 
         if (xlat_func(qc, scsicmd))
                 goto err_out;
-
         /* select device, send command to hardware */
         if (ata_qc_issue(qc))
                 goto err_out;
@@ -1304,7 +1606,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
         struct scsi_cmnd *cmd = qc->scsicmd;
         struct ata_device *dev = qc->dev;
         int using_pio = (dev->flags & ATA_DFLAG_PIO);
-        int nodata = (cmd->sc_data_direction == DMA_NONE);
+        int nodata = (cmd->sc_data_direction == SCSI_DATA_NONE);
 
         if (!using_pio)
                 /* Check whether ATAPI DMA is safe */
@@ -1316,7 +1618,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
         qc->complete_fn = atapi_qc_complete;
 
         qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
-        if (cmd->sc_data_direction == DMA_TO_DEVICE) {
+        if (cmd->sc_data_direction == SCSI_DATA_WRITE) {
                 qc->tf.flags |= ATA_TFLAG_WRITE;
                 DPRINTK("direction: write\n");
         }
@@ -1340,7 +1642,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 
 #ifdef ATAPI_ENABLE_DMADIR
                 /* some SATA bridges need us to indicate data xfer direction */
-                if (cmd->sc_data_direction != DMA_TO_DEVICE)
+                if (cmd->sc_data_direction != SCSI_DATA_WRITE)
                         qc->tf.feature |= ATAPI_DMADIR;
 #endif
         }
@@ -1393,6 +1695,143 @@ ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev)
         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 */
+                        if (byte1 & 0xe0) {
+                                return ATA_PROT_PIO_MULT;
+                        }
+                        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
+ *      @cmd: 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, u8 *scsicmd)
+{
+        struct ata_taskfile *tf = &(qc->tf);
+        struct scsi_cmnd *cmd = qc->scsicmd;
+
+        if ((tf->protocol = ata_scsi_map_proto(scsicmd[1])) == ATA_PROT_UNKNOWN)
+                return 1;
+
+        /*
+         * 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];
+        }
+
+        /*
+         * 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))
+                return 1;
+
+        /*
+         * 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 == SCSI_DATA_WRITE)
+                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->bufflen / ATA_SECT_SIZE;
+
+        return 0;
+}
+
 /**
  *      ata_get_xlat_func - check if SCSI to ATA translation is possible
  *      @dev: ATA device
@@ -1425,6 +1864,10 @@ static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
         case VERIFY:
         case VERIFY_16:
                 return ata_scsi_verify_xlat;
+
+        case ATA_12:
+        case ATA_16:
+                return ata_scsi_pass_thru;
         }
 
         return NULL;
@@ -1581,7 +2024,7 @@ void ata_scsi_simulate(u16 *id,
                         ata_scsi_rbuf_fill(&args, ata_scsiop_report_luns);
                         break;
 
-                /* mandantory commands we haven't implemented yet */
+                /* mandatory commands we haven't implemented yet */
                 case REQUEST_SENSE:
 
                 /* all other commands */