Merge branch 'linux-next' of git://git.infradead.org/~dedekind/ubi-2.6

[mirror_ubuntu-artful-kernel.git] / drivers / scsi / ide-scsi.c

/*
 * Copyright (C) 1996-1999  Gadi Oxman <gadio@netvision.net.il>
 * Copyright (C) 2004-2005  Bartlomiej Zolnierkiewicz
 */

/*
 * Emulation of a SCSI host adapter for IDE ATAPI devices.
 *
 * With this driver, one can use the Linux SCSI drivers instead of the
 * native IDE ATAPI drivers.
 *
 * Ver 0.1   Dec  3 96   Initial version.
 * Ver 0.2   Jan 26 97   Fixed bug in cleanup_module() and added emulation
 *                        of MODE_SENSE_6/MODE_SELECT_6 for cdroms. Thanks
 *                        to Janos Farkas for pointing this out.
 *                       Avoid using bitfields in structures for m68k.
 *                       Added Scatter/Gather and DMA support.
 * Ver 0.4   Dec  7 97   Add support for ATAPI PD/CD drives.
 *                       Use variable timeout for each command.
 * Ver 0.5   Jan  2 98   Fix previous PD/CD support.
 *                       Allow disabling of SCSI-6 to SCSI-10 transformation.
 * Ver 0.6   Jan 27 98   Allow disabling of SCSI command translation layer
 *                        for access through /dev/sg.
 *                       Fix MODE_SENSE_6/MODE_SELECT_6/INQUIRY translation.
 * Ver 0.7   Dec 04 98   Ignore commands where lun != 0 to avoid multiple
 *                        detection of devices with CONFIG_SCSI_MULTI_LUN
 * Ver 0.8   Feb 05 99   Optical media need translation too. Reverse 0.7.
 * Ver 0.9   Jul 04 99   Fix a bug in SG_SET_TRANSFORM.
 * Ver 0.91  Jun 10 02   Fix "off by one" error in transforms
 * Ver 0.92  Dec 31 02   Implement new SCSI mid level API
 */

#define IDESCSI_VERSION "0.92"

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/slab.h>
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/bitops.h>

#include <asm/io.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include <scsi/sg.h>

#define IDESCSI_DEBUG_LOG               0

#if IDESCSI_DEBUG_LOG
#define debug_log(fmt, args...) \
        printk(KERN_INFO "ide-scsi: " fmt, ## args)
#else
#define debug_log(fmt, args...) do {} while (0)
#endif

/*
 *      SCSI command transformation layer
 */
#define IDESCSI_SG_TRANSFORM            1       /* /dev/sg transformation */

/*
 *      Log flags
 */
#define IDESCSI_LOG_CMD                 0       /* Log SCSI commands */

typedef struct ide_scsi_obj {
        ide_drive_t             *drive;
        ide_driver_t            *driver;
        struct gendisk          *disk;
        struct Scsi_Host        *host;

        struct ide_atapi_pc *pc;                /* Current packet command */
        unsigned long transform;                /* SCSI cmd translation layer */
        unsigned long log;                      /* log flags */
} idescsi_scsi_t;

static DEFINE_MUTEX(idescsi_ref_mutex);
/* Set by module param to skip cd */
static int idescsi_nocd;

#define ide_scsi_g(disk) \
        container_of((disk)->private_data, struct ide_scsi_obj, driver)

static struct ide_scsi_obj *ide_scsi_get(struct gendisk *disk)
{
        struct ide_scsi_obj *scsi = NULL;

        mutex_lock(&idescsi_ref_mutex);
        scsi = ide_scsi_g(disk);
        if (scsi) {
                scsi_host_get(scsi->host);
                if (ide_device_get(scsi->drive)) {
                        scsi_host_put(scsi->host);
                        scsi = NULL;
                }
        }
        mutex_unlock(&idescsi_ref_mutex);
        return scsi;
}

static void ide_scsi_put(struct ide_scsi_obj *scsi)
{
        mutex_lock(&idescsi_ref_mutex);
        ide_device_put(scsi->drive);
        scsi_host_put(scsi->host);
        mutex_unlock(&idescsi_ref_mutex);
}

static inline idescsi_scsi_t *scsihost_to_idescsi(struct Scsi_Host *host)
{
        return (idescsi_scsi_t*) (&host[1]);
}

static inline idescsi_scsi_t *drive_to_idescsi(ide_drive_t *ide_drive)
{
        return scsihost_to_idescsi(ide_drive->driver_data);
}

/*
 *      PIO data transfer routine using the scatter gather table.
 */
static void ide_scsi_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                                unsigned int bcount, int write)
{
        ide_hwif_t *hwif = drive->hwif;
        const struct ide_tp_ops *tp_ops = hwif->tp_ops;
        xfer_func_t *xf = write ? tp_ops->output_data : tp_ops->input_data;
        char *buf;
        int count;

        while (bcount) {
                count = min(pc->sg->length - pc->b_count, bcount);
                if (PageHighMem(sg_page(pc->sg))) {
                        unsigned long flags;

                        local_irq_save(flags);
                        buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
                                          pc->sg->offset;
                        xf(drive, NULL, buf + pc->b_count, count);
                        kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
                        local_irq_restore(flags);
                } else {
                        buf = sg_virt(pc->sg);
                        xf(drive, NULL, buf + pc->b_count, count);
                }
                bcount -= count; pc->b_count += count;
                if (pc->b_count == pc->sg->length) {
                        if (!--pc->sg_cnt)
                                break;
                        pc->sg = sg_next(pc->sg);
                        pc->b_count = 0;
                }
        }

        if (bcount) {
                printk(KERN_ERR "%s: scatter gather table too small, %s\n",
                                drive->name, write ? "padding with zeros"
                                                   : "discarding data");
                ide_pad_transfer(drive, write, bcount);
        }
}

static void ide_scsi_hex_dump(u8 *data, int len)
{
        print_hex_dump(KERN_CONT, "", DUMP_PREFIX_NONE, 16, 1, data, len, 0);
}

static int idescsi_end_request(ide_drive_t *, int, int);

static void ide_scsi_callback(ide_drive_t *drive)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);
        struct ide_atapi_pc *pc = scsi->pc;

        if (pc->flags & PC_FLAG_TIMEDOUT)
                debug_log("%s: got timed out packet %lu at %lu\n", __func__,
                          pc->scsi_cmd->serial_number, jiffies);
                /* end this request now - scsi should retry it*/
        else if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
                printk(KERN_INFO "Packet command completed, %d bytes"
                                 " transferred\n", pc->xferred);

        idescsi_end_request(drive, 1, 0);
}

static int idescsi_check_condition(ide_drive_t *drive,
                struct request *failed_cmd)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);
        struct ide_atapi_pc   *pc;
        struct request *rq;
        u8             *buf;

        /* stuff a sense request in front of our current request */
        pc = kzalloc(sizeof(struct ide_atapi_pc), GFP_ATOMIC);
        rq = blk_get_request(drive->queue, READ, GFP_ATOMIC);
        buf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_ATOMIC);
        if (!pc || !rq || !buf) {
                kfree(buf);
                if (rq)
                        blk_put_request(rq);
                kfree(pc);
                return -ENOMEM;
        }
        rq->special = (char *) pc;
        pc->rq = rq;
        pc->buf = buf;
        pc->c[0] = REQUEST_SENSE;
        pc->c[4] = pc->req_xfer = pc->buf_size = SCSI_SENSE_BUFFERSIZE;
        rq->cmd_type = REQ_TYPE_SENSE;
        rq->cmd_flags |= REQ_PREEMPT;
        pc->timeout = jiffies + WAIT_READY;
        /* NOTE! Save the failed packet command in "rq->buffer" */
        rq->buffer = (void *) failed_cmd->special;
        pc->scsi_cmd = ((struct ide_atapi_pc *) failed_cmd->special)->scsi_cmd;
        if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
                printk ("ide-scsi: %s: queue cmd = ", drive->name);
                ide_scsi_hex_dump(pc->c, 6);
        }
        rq->rq_disk = scsi->disk;
        rq->ref_count++;
        memcpy(rq->cmd, pc->c, 12);
        ide_do_drive_cmd(drive, rq);
        return 0;
}

static ide_startstop_t
idescsi_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
{
        ide_hwif_t *hwif = drive->hwif;

        if (hwif->tp_ops->read_status(hwif) & (BUSY_STAT | DRQ_STAT))
                /* force an abort */
                hwif->tp_ops->exec_command(hwif, WIN_IDLEIMMEDIATE);

        rq->errors++;

        idescsi_end_request(drive, 0, 0);

        return ide_stopped;
}

static int idescsi_end_request (ide_drive_t *drive, int uptodate, int nrsecs)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);
        struct request *rq = HWGROUP(drive)->rq;
        struct ide_atapi_pc *pc = (struct ide_atapi_pc *) rq->special;
        int log = test_bit(IDESCSI_LOG_CMD, &scsi->log);
        struct Scsi_Host *host;
        int errors = rq->errors;
        unsigned long flags;

        if (!blk_special_request(rq) && !blk_sense_request(rq)) {
                ide_end_request(drive, uptodate, nrsecs);
                return 0;
        }
        ide_end_drive_cmd (drive, 0, 0);
        if (blk_sense_request(rq)) {
                struct ide_atapi_pc *opc = (struct ide_atapi_pc *) rq->buffer;
                if (log) {
                        printk ("ide-scsi: %s: wrap up check %lu, rst = ", drive->name, opc->scsi_cmd->serial_number);
                        ide_scsi_hex_dump(pc->buf, 16);
                }
                memcpy((void *) opc->scsi_cmd->sense_buffer, pc->buf,
                        SCSI_SENSE_BUFFERSIZE);
                kfree(pc->buf);
                kfree(pc);
                blk_put_request(rq);
                pc = opc;
                rq = pc->rq;
                pc->scsi_cmd->result = (CHECK_CONDITION << 1) |
                                (((pc->flags & PC_FLAG_TIMEDOUT) ?
                                  DID_TIME_OUT :
                                  DID_OK) << 16);
        } else if (pc->flags & PC_FLAG_TIMEDOUT) {
                if (log)
                        printk (KERN_WARNING "ide-scsi: %s: timed out for %lu\n",
                                        drive->name, pc->scsi_cmd->serial_number);
                pc->scsi_cmd->result = DID_TIME_OUT << 16;
        } else if (errors >= ERROR_MAX) {
                pc->scsi_cmd->result = DID_ERROR << 16;
                if (log)
                        printk ("ide-scsi: %s: I/O error for %lu\n", drive->name, pc->scsi_cmd->serial_number);
        } else if (errors) {
                if (log)
                        printk ("ide-scsi: %s: check condition for %lu\n", drive->name, pc->scsi_cmd->serial_number);
                if (!idescsi_check_condition(drive, rq))
                        /* we started a request sense, so we'll be back, exit for now */
                        return 0;
                pc->scsi_cmd->result = (CHECK_CONDITION << 1) | (DID_OK << 16);
        } else {
                pc->scsi_cmd->result = DID_OK << 16;
        }
        host = pc->scsi_cmd->device->host;
        spin_lock_irqsave(host->host_lock, flags);
        pc->done(pc->scsi_cmd);
        spin_unlock_irqrestore(host->host_lock, flags);
        kfree(pc);
        blk_put_request(rq);
        scsi->pc = NULL;
        return 0;
}

static inline unsigned long get_timeout(struct ide_atapi_pc *pc)
{
        return max_t(unsigned long, WAIT_CMD, pc->timeout - jiffies);
}

static int idescsi_expiry(ide_drive_t *drive)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);
        struct ide_atapi_pc   *pc   = scsi->pc;

        debug_log("%s called for %lu at %lu\n", __func__,
                  pc->scsi_cmd->serial_number, jiffies);

        pc->flags |= PC_FLAG_TIMEDOUT;

        return 0;                                       /* we do not want the ide subsystem to retry */
}

/*
 *      Our interrupt handler.
 */
static ide_startstop_t idescsi_pc_intr (ide_drive_t *drive)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);
        struct ide_atapi_pc *pc = scsi->pc;

        return ide_pc_intr(drive, pc, idescsi_pc_intr, get_timeout(pc),
                           idescsi_expiry, NULL, NULL, NULL,
                           ide_scsi_io_buffers);
}

static ide_startstop_t idescsi_transfer_pc(ide_drive_t *drive)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);

        return ide_transfer_pc(drive, scsi->pc, idescsi_pc_intr,
                               get_timeout(scsi->pc), idescsi_expiry);
}

static inline int idescsi_set_direction(struct ide_atapi_pc *pc)
{
        switch (pc->c[0]) {
                case READ_6: case READ_10: case READ_12:
                        pc->flags &= ~PC_FLAG_WRITING;
                        return 0;
                case WRITE_6: case WRITE_10: case WRITE_12:
                        pc->flags |= PC_FLAG_WRITING;
                        return 0;
                default:
                        return 1;
        }
}

static int idescsi_map_sg(ide_drive_t *drive, struct ide_atapi_pc *pc)
{
        ide_hwif_t *hwif = drive->hwif;
        struct scatterlist *sg, *scsi_sg;
        int segments;

        if (!pc->req_xfer || pc->req_xfer % 1024)
                return 1;

        if (idescsi_set_direction(pc))
                return 1;

        sg = hwif->sg_table;
        scsi_sg = scsi_sglist(pc->scsi_cmd);
        segments = scsi_sg_count(pc->scsi_cmd);

        if (segments > hwif->sg_max_nents)
                return 1;

        hwif->sg_nents = segments;
        memcpy(sg, scsi_sg, sizeof(*sg) * segments);

        return 0;
}

static ide_startstop_t idescsi_issue_pc(ide_drive_t *drive,
                struct ide_atapi_pc *pc)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);

        /* Set the current packet command */
        scsi->pc = pc;

        return ide_issue_pc(drive, pc, idescsi_transfer_pc,
                            get_timeout(pc), idescsi_expiry);
}

/*
 *      idescsi_do_request is our request handling function.
 */
static ide_startstop_t idescsi_do_request (ide_drive_t *drive, struct request *rq, sector_t block)
{
        debug_log("dev: %s, cmd: %x, errors: %d\n", rq->rq_disk->disk_name,
                  rq->cmd[0], rq->errors);
        debug_log("sector: %ld, nr_sectors: %ld, current_nr_sectors: %d\n",
                  rq->sector, rq->nr_sectors, rq->current_nr_sectors);

        if (blk_sense_request(rq) || blk_special_request(rq)) {
                struct ide_atapi_pc *pc = (struct ide_atapi_pc *)rq->special;

                if (drive->using_dma && !idescsi_map_sg(drive, pc))
                        pc->flags |= PC_FLAG_DMA_OK;

                return idescsi_issue_pc(drive, pc);
        }
        blk_dump_rq_flags(rq, "ide-scsi: unsup command");
        idescsi_end_request (drive, 0, 0);
        return ide_stopped;
}

#ifdef CONFIG_IDE_PROC_FS
static void idescsi_add_settings(ide_drive_t *drive)
{
        idescsi_scsi_t *scsi = drive_to_idescsi(drive);

/*
 *                      drive   setting name    read/write      data type       min     max     mul_factor      div_factor      data pointer            set function
 */
        ide_add_setting(drive,  "bios_cyl",     SETTING_RW,     TYPE_INT,       0,      1023,   1,              1,              &drive->bios_cyl,       NULL);
        ide_add_setting(drive,  "bios_head",    SETTING_RW,     TYPE_BYTE,      0,      255,    1,              1,              &drive->bios_head,      NULL);
        ide_add_setting(drive,  "bios_sect",    SETTING_RW,     TYPE_BYTE,      0,      63,     1,              1,              &drive->bios_sect,      NULL);
        ide_add_setting(drive,  "transform",    SETTING_RW,     TYPE_INT,       0,      3,      1,              1,              &scsi->transform,       NULL);
        ide_add_setting(drive,  "log",          SETTING_RW,     TYPE_INT,       0,      1,      1,              1,              &scsi->log,             NULL);
}
#else
static inline void idescsi_add_settings(ide_drive_t *drive) { ; }
#endif

/*
 *      Driver initialization.
 */
static void idescsi_setup (ide_drive_t *drive, idescsi_scsi_t *scsi)
{
        if (drive->id && (drive->id->config & 0x0060) == 0x20)
                set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
        clear_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
#if IDESCSI_DEBUG_LOG
        set_bit(IDESCSI_LOG_CMD, &scsi->log);
#endif /* IDESCSI_DEBUG_LOG */

        drive->pc_callback = ide_scsi_callback;

        idescsi_add_settings(drive);
}

static void ide_scsi_remove(ide_drive_t *drive)
{
        struct Scsi_Host *scsihost = drive->driver_data;
        struct ide_scsi_obj *scsi = scsihost_to_idescsi(scsihost);
        struct gendisk *g = scsi->disk;

        scsi_remove_host(scsihost);
        ide_proc_unregister_driver(drive, scsi->driver);

        ide_unregister_region(g);

        drive->driver_data = NULL;
        g->private_data = NULL;
        put_disk(g);

        ide_scsi_put(scsi);

        drive->scsi = 0;
}

static int ide_scsi_probe(ide_drive_t *);

#ifdef CONFIG_IDE_PROC_FS
static ide_proc_entry_t idescsi_proc[] = {
        { "capacity", S_IFREG|S_IRUGO, proc_ide_read_capacity, NULL },
        { NULL, 0, NULL, NULL }
};
#endif

static ide_driver_t idescsi_driver = {
        .gen_driver = {
                .owner          = THIS_MODULE,
                .name           = "ide-scsi",
                .bus            = &ide_bus_type,
        },
        .probe                  = ide_scsi_probe,
        .remove                 = ide_scsi_remove,
        .version                = IDESCSI_VERSION,
        .media                  = ide_scsi,
        .supports_dsc_overlap   = 0,
        .do_request             = idescsi_do_request,
        .end_request            = idescsi_end_request,
        .error                  = idescsi_atapi_error,
#ifdef CONFIG_IDE_PROC_FS
        .proc                   = idescsi_proc,
#endif
};

static int idescsi_ide_open(struct inode *inode, struct file *filp)
{
        struct gendisk *disk = inode->i_bdev->bd_disk;
        struct ide_scsi_obj *scsi;

        if (!(scsi = ide_scsi_get(disk)))
                return -ENXIO;

        return 0;
}

static int idescsi_ide_release(struct inode *inode, struct file *filp)
{
        struct gendisk *disk = inode->i_bdev->bd_disk;
        struct ide_scsi_obj *scsi = ide_scsi_g(disk);

        ide_scsi_put(scsi);

        return 0;
}

static int idescsi_ide_ioctl(struct inode *inode, struct file *file,
                        unsigned int cmd, unsigned long arg)
{
        struct block_device *bdev = inode->i_bdev;
        struct ide_scsi_obj *scsi = ide_scsi_g(bdev->bd_disk);
        return generic_ide_ioctl(scsi->drive, file, bdev, cmd, arg);
}

static struct block_device_operations idescsi_ops = {
        .owner          = THIS_MODULE,
        .open           = idescsi_ide_open,
        .release        = idescsi_ide_release,
        .ioctl          = idescsi_ide_ioctl,
};

static int idescsi_slave_configure(struct scsi_device * sdp)
{
        /* Configure detected device */
        sdp->use_10_for_rw = 1;
        sdp->use_10_for_ms = 1;
        scsi_adjust_queue_depth(sdp, MSG_SIMPLE_TAG, sdp->host->cmd_per_lun);
        return 0;
}

static const char *idescsi_info (struct Scsi_Host *host)
{
        return "SCSI host adapter emulation for IDE ATAPI devices";
}

static int idescsi_ioctl (struct scsi_device *dev, int cmd, void __user *arg)
{
        idescsi_scsi_t *scsi = scsihost_to_idescsi(dev->host);

        if (cmd == SG_SET_TRANSFORM) {
                if (arg)
                        set_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
                else
                        clear_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
                return 0;
        } else if (cmd == SG_GET_TRANSFORM)
                return put_user(test_bit(IDESCSI_SG_TRANSFORM, &scsi->transform), (int __user *) arg);
        return -EINVAL;
}

static int idescsi_queue (struct scsi_cmnd *cmd,
                void (*done)(struct scsi_cmnd *))
{
        struct Scsi_Host *host = cmd->device->host;
        idescsi_scsi_t *scsi = scsihost_to_idescsi(host);
        ide_drive_t *drive = scsi->drive;
        struct request *rq = NULL;
        struct ide_atapi_pc *pc = NULL;
        int write = cmd->sc_data_direction == DMA_TO_DEVICE;

        if (!drive) {
                scmd_printk (KERN_ERR, cmd, "drive not present\n");
                goto abort;
        }
        scsi = drive_to_idescsi(drive);
        pc = kmalloc(sizeof(struct ide_atapi_pc), GFP_ATOMIC);
        rq = blk_get_request(drive->queue, write, GFP_ATOMIC);
        if (rq == NULL || pc == NULL) {
                printk (KERN_ERR "ide-scsi: %s: out of memory\n", drive->name);
                goto abort;
        }

        memset (pc->c, 0, 12);
        pc->flags = 0;
        if (cmd->sc_data_direction == DMA_TO_DEVICE)
                pc->flags |= PC_FLAG_WRITING;
        pc->rq = rq;
        memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
        pc->buf = NULL;
        pc->sg = scsi_sglist(cmd);
        pc->sg_cnt = scsi_sg_count(cmd);
        pc->b_count = 0;
        pc->req_xfer = pc->buf_size = scsi_bufflen(cmd);
        pc->scsi_cmd = cmd;
        pc->done = done;
        pc->timeout = jiffies + cmd->timeout_per_command;

        if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
                printk ("ide-scsi: %s: que %lu, cmd = ", drive->name, cmd->serial_number);
                ide_scsi_hex_dump(cmd->cmnd, cmd->cmd_len);
                if (memcmp(pc->c, cmd->cmnd, cmd->cmd_len)) {
                        printk ("ide-scsi: %s: que %lu, tsl = ", drive->name, cmd->serial_number);
                        ide_scsi_hex_dump(pc->c, 12);
                }
        }

        rq->special = (char *) pc;
        rq->cmd_type = REQ_TYPE_SPECIAL;
        spin_unlock_irq(host->host_lock);
        rq->ref_count++;
        memcpy(rq->cmd, pc->c, 12);
        blk_execute_rq_nowait(drive->queue, scsi->disk, rq, 0, NULL);
        spin_lock_irq(host->host_lock);
        return 0;
abort:
        kfree (pc);
        if (rq)
                blk_put_request(rq);
        cmd->result = DID_ERROR << 16;
        done(cmd);
        return 0;
}

static int idescsi_eh_abort (struct scsi_cmnd *cmd)
{
        idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
        ide_drive_t    *drive = scsi->drive;
        int             busy;
        int             ret   = FAILED;

        /* In idescsi_eh_abort we try to gently pry our command from the ide subsystem */

        if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
                printk (KERN_WARNING "ide-scsi: abort called for %lu\n", cmd->serial_number);

        if (!drive) {
                printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_abort\n");
                WARN_ON(1);
                goto no_drive;
        }

        /* First give it some more time, how much is "right" is hard to say :-( */

        busy = ide_wait_not_busy(HWIF(drive), 100);     /* FIXME - uses mdelay which causes latency? */
        if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
                printk (KERN_WARNING "ide-scsi: drive did%s become ready\n", busy?" not":"");

        spin_lock_irq(&ide_lock);

        /* If there is no pc running we're done (our interrupt took care of it) */
        if (!scsi->pc) {
                ret = SUCCESS;
                goto ide_unlock;
        }

        /* It's somewhere in flight. Does ide subsystem agree? */
        if (scsi->pc->scsi_cmd->serial_number == cmd->serial_number && !busy &&
            elv_queue_empty(drive->queue) && HWGROUP(drive)->rq != scsi->pc->rq) {
                /*
                 * FIXME - not sure this condition can ever occur
                 */
                printk (KERN_ERR "ide-scsi: cmd aborted!\n");

                if (blk_sense_request(scsi->pc->rq))
                        kfree(scsi->pc->buf);
                /* we need to call blk_put_request twice. */
                blk_put_request(scsi->pc->rq);
                blk_put_request(scsi->pc->rq);
                kfree(scsi->pc);
                scsi->pc = NULL;

                ret = SUCCESS;
        }

ide_unlock:
        spin_unlock_irq(&ide_lock);
no_drive:
        if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
                printk (KERN_WARNING "ide-scsi: abort returns %s\n", ret == SUCCESS?"success":"failed");

        return ret;
}

static int idescsi_eh_reset (struct scsi_cmnd *cmd)
{
        struct request *req;
        idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
        ide_drive_t    *drive = scsi->drive;
        int             ready = 0;
        int             ret   = SUCCESS;

        /* In idescsi_eh_reset we forcefully remove the command from the ide subsystem and reset the device. */

        if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
                printk (KERN_WARNING "ide-scsi: reset called for %lu\n", cmd->serial_number);

        if (!drive) {
                printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_reset\n");
                WARN_ON(1);
                return FAILED;
        }

        spin_lock_irq(cmd->device->host->host_lock);
        spin_lock(&ide_lock);

        if (!scsi->pc || (req = scsi->pc->rq) != HWGROUP(drive)->rq || !HWGROUP(drive)->handler) {
                printk (KERN_WARNING "ide-scsi: No active request in idescsi_eh_reset\n");
                spin_unlock(&ide_lock);
                spin_unlock_irq(cmd->device->host->host_lock);
                return FAILED;
        }

        /* kill current request */
        if (__blk_end_request(req, -EIO, 0))
                BUG();
        if (blk_sense_request(req))
                kfree(scsi->pc->buf);
        kfree(scsi->pc);
        scsi->pc = NULL;
        blk_put_request(req);

        /* now nuke the drive queue */
        while ((req = elv_next_request(drive->queue))) {
                if (__blk_end_request(req, -EIO, 0))
                        BUG();
        }

        HWGROUP(drive)->rq = NULL;
        HWGROUP(drive)->handler = NULL;
        HWGROUP(drive)->busy = 1;               /* will set this to zero when ide reset finished */
        spin_unlock(&ide_lock);

        ide_do_reset(drive);

        /* ide_do_reset starts a polling handler which restarts itself every 50ms until the reset finishes */

        do {
                spin_unlock_irq(cmd->device->host->host_lock);
                msleep(50);
                spin_lock_irq(cmd->device->host->host_lock);
        } while ( HWGROUP(drive)->handler );

        ready = drive_is_ready(drive);
        HWGROUP(drive)->busy--;
        if (!ready) {
                printk (KERN_ERR "ide-scsi: reset failed!\n");
                ret = FAILED;
        }

        spin_unlock_irq(cmd->device->host->host_lock);
        return ret;
}

static int idescsi_bios(struct scsi_device *sdev, struct block_device *bdev,
                sector_t capacity, int *parm)
{
        idescsi_scsi_t *idescsi = scsihost_to_idescsi(sdev->host);
        ide_drive_t *drive = idescsi->drive;

        if (drive->bios_cyl && drive->bios_head && drive->bios_sect) {
                parm[0] = drive->bios_head;
                parm[1] = drive->bios_sect;
                parm[2] = drive->bios_cyl;
        }
        return 0;
}

static struct scsi_host_template idescsi_template = {
        .module                 = THIS_MODULE,
        .name                   = "idescsi",
        .info                   = idescsi_info,
        .slave_configure        = idescsi_slave_configure,
        .ioctl                  = idescsi_ioctl,
        .queuecommand           = idescsi_queue,
        .eh_abort_handler       = idescsi_eh_abort,
        .eh_host_reset_handler  = idescsi_eh_reset,
        .bios_param             = idescsi_bios,
        .can_queue              = 40,
        .this_id                = -1,
        .sg_tablesize           = 256,
        .cmd_per_lun            = 5,
        .max_sectors            = 128,
        .use_clustering         = DISABLE_CLUSTERING,
        .emulated               = 1,
        .proc_name              = "ide-scsi",
};

static int ide_scsi_probe(ide_drive_t *drive)
{
        idescsi_scsi_t *idescsi;
        struct Scsi_Host *host;
        struct gendisk *g;
        static int warned;
        int err = -ENOMEM;

        if (!warned && drive->media == ide_cdrom) {
                printk(KERN_WARNING "ide-scsi is deprecated for cd burning! Use ide-cd and give dev=/dev/hdX as device\n");
                warned = 1;
        }

        if (idescsi_nocd && drive->media == ide_cdrom)
                return -ENODEV;

        if (!strstr("ide-scsi", drive->driver_req) ||
            !drive->present ||
            drive->media == ide_disk ||
            !(host = scsi_host_alloc(&idescsi_template,sizeof(idescsi_scsi_t))))
                return -ENODEV;

        drive->scsi = 1;

        g = alloc_disk(1 << PARTN_BITS);
        if (!g)
                goto out_host_put;

        ide_init_disk(g, drive);

        host->max_id = 1;

        if (drive->id->last_lun)
                debug_log("%s: id->last_lun=%u\n", drive->name,
                          drive->id->last_lun);

        if ((drive->id->last_lun & 0x7) != 7)
                host->max_lun = (drive->id->last_lun & 0x7) + 1;
        else
                host->max_lun = 1;

        drive->driver_data = host;
        idescsi = scsihost_to_idescsi(host);
        idescsi->drive = drive;
        idescsi->driver = &idescsi_driver;
        idescsi->host = host;
        idescsi->disk = g;
        g->private_data = &idescsi->driver;
        ide_proc_register_driver(drive, &idescsi_driver);
        err = 0;
        idescsi_setup(drive, idescsi);
        g->fops = &idescsi_ops;
        ide_register_region(g);
        err = scsi_add_host(host, &drive->gendev);
        if (!err) {
                scsi_scan_host(host);
                return 0;
        }
        /* fall through on error */
        ide_unregister_region(g);
        ide_proc_unregister_driver(drive, &idescsi_driver);

        put_disk(g);
out_host_put:
        drive->scsi = 0;
        scsi_host_put(host);
        return err;
}

static int __init init_idescsi_module(void)
{
        return driver_register(&idescsi_driver.gen_driver);
}

static void __exit exit_idescsi_module(void)
{
        driver_unregister(&idescsi_driver.gen_driver);
}

module_param(idescsi_nocd, int, 0600);
MODULE_PARM_DESC(idescsi_nocd, "Disable handling of CD-ROMs so they may be driven by ide-cd");
module_init(init_idescsi_module);
module_exit(exit_idescsi_module);
MODULE_LICENSE("GPL");