sas_ata.c

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/*
 * Support for SATA devices on Serial Attached SCSI (SAS) controllers
 *
 * Copyright (C) 2006 IBM Corporation
 *
 * Written by: Darrick J. Wong <[email protected]>, IBM Corporation
 *
 * 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 of the
 * License, 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; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/async.h>
#include <linux/export.h>

#include <scsi/sas_ata.h>
#include "sas_internal.h"
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_sas.h>
#include "../scsi_sas_internal.h"
#include "../scsi_transport_api.h"
#include <scsi/scsi_eh.h>

static enum ata_completion_errors sas_to_ata_err(struct task_status_struct *ts)
{
    /* Cheesy attempt to translate SAS errors into ATA.  Hah! */

    /* transport error */
    if (ts->resp == SAS_TASK_UNDELIVERED)
        return AC_ERR_ATA_BUS;

    /* ts->resp == SAS_TASK_COMPLETE */
    /* task delivered, what happened afterwards? */
    switch (ts->stat) {
        case SAS_DEV_NO_RESPONSE:
            return AC_ERR_TIMEOUT;

        case SAS_INTERRUPTED:
        case SAS_PHY_DOWN:
        case SAS_NAK_R_ERR:
            return AC_ERR_ATA_BUS;


        case SAS_DATA_UNDERRUN:
            /*
             * Some programs that use the taskfile interface
             * (smartctl in particular) can cause underrun
             * problems.  Ignore these errors, perhaps at our
             * peril.
             */
            return 0;

        case SAS_DATA_OVERRUN:
        case SAS_QUEUE_FULL:
        case SAS_DEVICE_UNKNOWN:
        case SAS_SG_ERR:
            return AC_ERR_INVALID;

        case SAS_OPEN_TO:
        case SAS_OPEN_REJECT:
            SAS_DPRINTK("%s: Saw error %d.  What to do?\n",
                    __func__, ts->stat);
            return AC_ERR_OTHER;

        case SAM_STAT_CHECK_CONDITION:
        case SAS_ABORTED_TASK:
            return AC_ERR_DEV;

        case SAS_PROTO_RESPONSE:
            /* This means the ending_fis has the error
             * value; return 0 here to collect it */
            return 0;
        default:
            return 0;
    }
}

static void sas_ata_task_done(struct sas_task *task)
{
    struct ata_queued_cmd *qc = task->uldd_task;
    struct domain_device *dev = task->dev;
    struct task_status_struct *stat = &task->task_status;
    struct ata_task_resp *resp = (struct ata_task_resp *)stat->buf;
    struct sas_ha_struct *sas_ha = dev->port->ha;
    enum ata_completion_errors ac;
    unsigned long flags;
    struct ata_link *link;
    struct ata_port *ap;

    spin_lock_irqsave(&dev->done_lock, flags);
    if (test_bit(SAS_HA_FROZEN, &sas_ha->state))
        task = NULL;
    else if (qc && qc->scsicmd)
        ASSIGN_SAS_TASK(qc->scsicmd, NULL);
    spin_unlock_irqrestore(&dev->done_lock, flags);

    /* check if libsas-eh got to the task before us */
    if (unlikely(!task))
        return;

    if (!qc)
        goto qc_already_gone;

    ap = qc->ap;
    link = &ap->link;

    spin_lock_irqsave(ap->lock, flags);
    /* check if we lost the race with libata/sas_ata_post_internal() */
    if (unlikely(ap->pflags & ATA_PFLAG_FROZEN)) {
        spin_unlock_irqrestore(ap->lock, flags);
        if (qc->scsicmd)
            goto qc_already_gone;
        else {
            /* if eh is not involved and the port is frozen then the
             * ata internal abort process has taken responsibility
             * for this sas_task
             */
            return;
        }
    }

    if (stat->stat == SAS_PROTO_RESPONSE || stat->stat == SAM_STAT_GOOD ||
        ((stat->stat == SAM_STAT_CHECK_CONDITION &&
          dev->sata_dev.command_set == ATAPI_COMMAND_SET))) {
        memcpy(dev->sata_dev.fis, resp->ending_fis, ATA_RESP_FIS_SIZE);

        if (!link->sactive) {
            qc->err_mask |= ac_err_mask(dev->sata_dev.fis[2]);
        } else {
            link->eh_info.err_mask |= ac_err_mask(dev->sata_dev.fis[2]);
            if (unlikely(link->eh_info.err_mask))
                qc->flags |= ATA_QCFLAG_FAILED;
        }
    } else {
        ac = sas_to_ata_err(stat);
        if (ac) {
            SAS_DPRINTK("%s: SAS error %x\n", __func__,
                    stat->stat);
            /* We saw a SAS error. Send a vague error. */
            if (!link->sactive) {
                qc->err_mask = ac;
            } else {
                link->eh_info.err_mask |= AC_ERR_DEV;
                qc->flags |= ATA_QCFLAG_FAILED;
            }

            dev->sata_dev.fis[3] = 0x04; /* status err */
            dev->sata_dev.fis[2] = ATA_ERR;
        }
    }

    qc->lldd_task = NULL;
    ata_qc_complete(qc);
    spin_unlock_irqrestore(ap->lock, flags);

qc_already_gone:
    list_del_init(&task->list);
    sas_free_task(task);
}

static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
{
    unsigned long flags;
    struct sas_task *task;
    struct scatterlist *sg;
    int ret = AC_ERR_SYSTEM;
    unsigned int si, xfer = 0;
    struct ata_port *ap = qc->ap;
    struct domain_device *dev = ap->private_data;
    struct sas_ha_struct *sas_ha = dev->port->ha;
    struct Scsi_Host *host = sas_ha->core.shost;
    struct sas_internal *i = to_sas_internal(host->transportt);

    /* TODO: audit callers to ensure they are ready for qc_issue to
     * unconditionally re-enable interrupts
     */
    local_irq_save(flags);
    spin_unlock(ap->lock);

    /* If the device fell off, no sense in issuing commands */
    if (test_bit(SAS_DEV_GONE, &dev->state))
        goto out;

    task = sas_alloc_task(GFP_ATOMIC);
    if (!task)
        goto out;
    task->dev = dev;
    task->task_proto = SAS_PROTOCOL_STP;
    task->task_done = sas_ata_task_done;

    if (qc->tf.command == ATA_CMD_FPDMA_WRITE ||
        qc->tf.command == ATA_CMD_FPDMA_READ) {
        /* Need to zero out the tag libata assigned us */
        qc->tf.nsect = 0;
    }

    ata_tf_to_fis(&qc->tf, 1, 0, (u8*)&task->ata_task.fis);
    task->uldd_task = qc;
    if (ata_is_atapi(qc->tf.protocol)) {
        memcpy(task->ata_task.atapi_packet, qc->cdb, qc->dev->cdb_len);
        task->total_xfer_len = qc->nbytes;
        task->num_scatter = qc->n_elem;
    } else {
        for_each_sg(qc->sg, sg, qc->n_elem, si)
            xfer += sg->length;

        task->total_xfer_len = xfer;
        task->num_scatter = si;
    }

    task->data_dir = qc->dma_dir;
    task->scatter = qc->sg;
    task->ata_task.retry_count = 1;
    task->task_state_flags = SAS_TASK_STATE_PENDING;
    qc->lldd_task = task;

    switch (qc->tf.protocol) {
    case ATA_PROT_NCQ:
        task->ata_task.use_ncq = 1;
        /* fall through */
    case ATAPI_PROT_DMA:
    case ATA_PROT_DMA:
        task->ata_task.dma_xfer = 1;
        break;
    }

    if (qc->scsicmd)
        ASSIGN_SAS_TASK(qc->scsicmd, task);

    if (sas_ha->lldd_max_execute_num < 2)
        ret = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);
    else
        ret = sas_queue_up(task);

    /* Examine */
    if (ret) {
        SAS_DPRINTK("lldd_execute_task returned: %d\n", ret);

        if (qc->scsicmd)
            ASSIGN_SAS_TASK(qc->scsicmd, NULL);
        sas_free_task(task);
        ret = AC_ERR_SYSTEM;
    }

 out:
    spin_lock(ap->lock);
    local_irq_restore(flags);
    return ret;
}

static bool sas_ata_qc_fill_rtf(struct ata_queued_cmd *qc)
{
    struct domain_device *dev = qc->ap->private_data;

    ata_tf_from_fis(dev->sata_dev.fis, &qc->result_tf);
    return true;
}

static struct sas_internal *dev_to_sas_internal(struct domain_device *dev)
{
    return to_sas_internal(dev->port->ha->core.shost->transportt);
}

static void sas_get_ata_command_set(struct domain_device *dev);

int sas_get_ata_info(struct domain_device *dev, struct ex_phy *phy)
{
    if (phy->attached_tproto & SAS_PROTOCOL_STP)
        dev->tproto = phy->attached_tproto;
    if (phy->attached_sata_dev)
        dev->tproto |= SATA_DEV;

    if (phy->attached_dev_type == SATA_PENDING)
        dev->dev_type = SATA_PENDING;
    else {
        int res;

        dev->dev_type = SATA_DEV;
        res = sas_get_report_phy_sata(dev->parent, phy->phy_id,
                          &dev->sata_dev.rps_resp);
        if (res) {
            SAS_DPRINTK("report phy sata to %016llx:0x%x returned "
                    "0x%x\n", SAS_ADDR(dev->parent->sas_addr),
                    phy->phy_id, res);
            return res;
        }
        memcpy(dev->frame_rcvd, &dev->sata_dev.rps_resp.rps.fis,
               sizeof(struct dev_to_host_fis));
        /* TODO switch to ata_dev_classify() */
        sas_get_ata_command_set(dev);
    }
    return 0;
}

static int sas_ata_clear_pending(struct domain_device *dev, struct ex_phy *phy)
{
    int res;

    /* we weren't pending, so successfully end the reset sequence now */
    if (dev->dev_type != SATA_PENDING)
        return 1;

    /* hmmm, if this succeeds do we need to repost the domain_device to the
     * lldd so it can pick up new parameters?
     */
    res = sas_get_ata_info(dev, phy);
    if (res)
        return 0; /* retry */
    else
        return 1;
}

static int smp_ata_check_ready(struct ata_link *link)
{
    int res;
    struct ata_port *ap = link->ap;
    struct domain_device *dev = ap->private_data;
    struct domain_device *ex_dev = dev->parent;
    struct sas_phy *phy = sas_get_local_phy(dev);
    struct ex_phy *ex_phy = &ex_dev->ex_dev.ex_phy[phy->number];

    res = sas_ex_phy_discover(ex_dev, phy->number);
    sas_put_local_phy(phy);

    /* break the wait early if the expander is unreachable,
     * otherwise keep polling
     */
    if (res == -ECOMM)
        return res;
    if (res != SMP_RESP_FUNC_ACC)
        return 0;

    switch (ex_phy->attached_dev_type) {
    case SATA_PENDING:
        return 0;
    case SAS_END_DEV:
        if (ex_phy->attached_sata_dev)
            return sas_ata_clear_pending(dev, ex_phy);
    default:
        return -ENODEV;
    }
}

static int local_ata_check_ready(struct ata_link *link)
{
    struct ata_port *ap = link->ap;
    struct domain_device *dev = ap->private_data;
    struct sas_internal *i = dev_to_sas_internal(dev);

    if (i->dft->lldd_ata_check_ready)
        return i->dft->lldd_ata_check_ready(dev);
    else {
        /* lldd's that don't implement 'ready' checking get the
         * old default behavior of not coordinating reset
         * recovery with libata
         */
        return 1;
    }
}

static int sas_ata_printk(const char *level, const struct domain_device *ddev,
              const char *fmt, ...)
{
    struct ata_port *ap = ddev->sata_dev.ap;
    struct device *dev = &ddev->rphy->dev;
    struct va_format vaf;
    va_list args;
    int r;

    va_start(args, fmt);

    vaf.fmt = fmt;
    vaf.va = &args;

    r = printk("%ssas: ata%u: %s: %pV",
           level, ap->print_id, dev_name(dev), &vaf);

    va_end(args);

    return r;
}

static int sas_ata_hard_reset(struct ata_link *link, unsigned int *class,
                  unsigned long deadline)
{
    int ret = 0, res;
    struct sas_phy *phy;
    struct ata_port *ap = link->ap;
    int (*check_ready)(struct ata_link *link);
    struct domain_device *dev = ap->private_data;
    struct sas_internal *i = dev_to_sas_internal(dev);

    res = i->dft->lldd_I_T_nexus_reset(dev);
    if (res == -ENODEV)
        return res;

    if (res != TMF_RESP_FUNC_COMPLETE)
        sas_ata_printk(KERN_DEBUG, dev, "Unable to reset ata device?\n");

    phy = sas_get_local_phy(dev);
    if (scsi_is_sas_phy_local(phy))
        check_ready = local_ata_check_ready;
    else
        check_ready = smp_ata_check_ready;
    sas_put_local_phy(phy);

    ret = ata_wait_after_reset(link, deadline, check_ready);
    if (ret && ret != -EAGAIN)
        sas_ata_printk(KERN_ERR, dev, "reset failed (errno=%d)\n", ret);

    /* XXX: if the class changes during the reset the upper layer
     * should be informed, if the device has gone away we assume
     * libsas will eventually delete it
     */
    switch (dev->sata_dev.command_set) {
    case ATA_COMMAND_SET:
        *class = ATA_DEV_ATA;
        break;
    case ATAPI_COMMAND_SET:
        *class = ATA_DEV_ATAPI;
        break;
    }

    ap->cbl = ATA_CBL_SATA;
    return ret;
}

/*
 * notify the lldd to forget the sas_task for this internal ata command
 * that bypasses scsi-eh
 */
static void sas_ata_internal_abort(struct sas_task *task)
{
    struct sas_internal *si = dev_to_sas_internal(task->dev);
    unsigned long flags;
    int res;

    spin_lock_irqsave(&task->task_state_lock, flags);
    if (task->task_state_flags & SAS_TASK_STATE_ABORTED ||
        task->task_state_flags & SAS_TASK_STATE_DONE) {
        spin_unlock_irqrestore(&task->task_state_lock, flags);
        SAS_DPRINTK("%s: Task %p already finished.\n", __func__,
                task);
        goto out;
    }
    task->task_state_flags |= SAS_TASK_STATE_ABORTED;
    spin_unlock_irqrestore(&task->task_state_lock, flags);

    res = si->dft->lldd_abort_task(task);

    spin_lock_irqsave(&task->task_state_lock, flags);
    if (task->task_state_flags & SAS_TASK_STATE_DONE ||
        res == TMF_RESP_FUNC_COMPLETE) {
        spin_unlock_irqrestore(&task->task_state_lock, flags);
        goto out;
    }

    /* XXX we are not prepared to deal with ->lldd_abort_task()
     * failures.  TODO: lldds need to unconditionally forget about
     * aborted ata tasks, otherwise we (likely) leak the sas task
     * here
     */
    SAS_DPRINTK("%s: Task %p leaked.\n", __func__, task);

    if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
        task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
    spin_unlock_irqrestore(&task->task_state_lock, flags);

    return;
 out:
    list_del_init(&task->list);
    sas_free_task(task);
}

static void sas_ata_post_internal(struct ata_queued_cmd *qc)
{
    if (qc->flags & ATA_QCFLAG_FAILED)
        qc->err_mask |= AC_ERR_OTHER;

    if (qc->err_mask) {
        /*
         * Find the sas_task and kill it.  By this point, libata
         * has decided to kill the qc and has frozen the port.
         * In this state sas_ata_task_done() will no longer free
         * the sas_task, so we need to notify the lldd (via
         * ->lldd_abort_task) that the task is dead and free it
         *  ourselves.
         */
        struct sas_task *task = qc->lldd_task;

        qc->lldd_task = NULL;
        if (!task)
            return;
        task->uldd_task = NULL;
        sas_ata_internal_abort(task);
    }
}


static void sas_ata_set_dmamode(struct ata_port *ap, struct ata_device *ata_dev)
{
    struct domain_device *dev = ap->private_data;
    struct sas_internal *i = dev_to_sas_internal(dev);

    if (i->dft->lldd_ata_set_dmamode)
        i->dft->lldd_ata_set_dmamode(dev);
}

static void sas_ata_sched_eh(struct ata_port *ap)
{
    struct domain_device *dev = ap->private_data;
    struct sas_ha_struct *ha = dev->port->ha;
    unsigned long flags;

    spin_lock_irqsave(&ha->lock, flags);
    if (!test_and_set_bit(SAS_DEV_EH_PENDING, &dev->state))
        ha->eh_active++;
    ata_std_sched_eh(ap);
    spin_unlock_irqrestore(&ha->lock, flags);
}

void sas_ata_end_eh(struct ata_port *ap)
{
    struct domain_device *dev = ap->private_data;
    struct sas_ha_struct *ha = dev->port->ha;
    unsigned long flags;

    spin_lock_irqsave(&ha->lock, flags);
    if (test_and_clear_bit(SAS_DEV_EH_PENDING, &dev->state))
        ha->eh_active--;
    spin_unlock_irqrestore(&ha->lock, flags);
}

static struct ata_port_operations sas_sata_ops = {
    .prereset       = ata_std_prereset,
    .hardreset      = sas_ata_hard_reset,
    .postreset      = ata_std_postreset,
    .error_handler      = ata_std_error_handler,
    .post_internal_cmd  = sas_ata_post_internal,
    .qc_defer               = ata_std_qc_defer,
    .qc_prep        = ata_noop_qc_prep,
    .qc_issue       = sas_ata_qc_issue,
    .qc_fill_rtf        = sas_ata_qc_fill_rtf,
    .port_start     = ata_sas_port_start,
    .port_stop      = ata_sas_port_stop,
    .set_dmamode        = sas_ata_set_dmamode,
    .sched_eh       = sas_ata_sched_eh,
    .end_eh         = sas_ata_end_eh,
};

static struct ata_port_info sata_port_info = {
    .flags = ATA_FLAG_SATA | ATA_FLAG_PIO_DMA | ATA_FLAG_NCQ,
    .pio_mask = ATA_PIO4,
    .mwdma_mask = ATA_MWDMA2,
    .udma_mask = ATA_UDMA6,
    .port_ops = &sas_sata_ops
};

int sas_ata_init(struct domain_device *found_dev)
{
    struct sas_ha_struct *ha = found_dev->port->ha;
    struct Scsi_Host *shost = ha->core.shost;
    struct ata_port *ap;
    int rc;

    ata_host_init(&found_dev->sata_dev.ata_host, ha->dev, &sas_sata_ops);
    ap = ata_sas_port_alloc(&found_dev->sata_dev.ata_host,
                &sata_port_info,
                shost);
    if (!ap) {
        SAS_DPRINTK("ata_sas_port_alloc failed.\n");
        return -ENODEV;
    }

    ap->private_data = found_dev;
    ap->cbl = ATA_CBL_SATA;
    ap->scsi_host = shost;
    rc = ata_sas_port_init(ap);
    if (rc) {
        ata_sas_port_destroy(ap);
        return rc;
    }
    found_dev->sata_dev.ap = ap;

    return 0;
}

void sas_ata_task_abort(struct sas_task *task)
{
    struct ata_queued_cmd *qc = task->uldd_task;
    struct completion *waiting;

    /* Bounce SCSI-initiated commands to the SCSI EH */
    if (qc->scsicmd) {
        struct request_queue *q = qc->scsicmd->device->request_queue;
        unsigned long flags;

        spin_lock_irqsave(q->queue_lock, flags);
        blk_abort_request(qc->scsicmd->request);
        spin_unlock_irqrestore(q->queue_lock, flags);
        return;
    }

    /* Internal command, fake a timeout and complete. */
    qc->flags &= ~ATA_QCFLAG_ACTIVE;
    qc->flags |= ATA_QCFLAG_FAILED;
    qc->err_mask |= AC_ERR_TIMEOUT;
    waiting = qc->private_data;
    complete(waiting);
}

static void sas_get_ata_command_set(struct domain_device *dev)
{
    struct dev_to_host_fis *fis =
        (struct dev_to_host_fis *) dev->frame_rcvd;

    if (dev->dev_type == SATA_PENDING)
        return;

    if ((fis->sector_count == 1 && /* ATA */
         fis->lbal         == 1 &&
         fis->lbam         == 0 &&
         fis->lbah         == 0 &&
         fis->device       == 0)
        ||
        (fis->sector_count == 0 && /* CE-ATA (mATA) */
         fis->lbal         == 0 &&
         fis->lbam         == 0xCE &&
         fis->lbah         == 0xAA &&
         (fis->device & ~0x10) == 0))

        dev->sata_dev.command_set = ATA_COMMAND_SET;

    else if ((fis->interrupt_reason == 1 && /* ATAPI */
          fis->lbal             == 1 &&
          fis->byte_count_low   == 0x14 &&
          fis->byte_count_high  == 0xEB &&
          (fis->device & ~0x10) == 0))

        dev->sata_dev.command_set = ATAPI_COMMAND_SET;

    else if ((fis->sector_count == 1 && /* SEMB */
          fis->lbal         == 1 &&
          fis->lbam         == 0x3C &&
          fis->lbah         == 0xC3 &&
          fis->device       == 0)
        ||
         (fis->interrupt_reason == 1 && /* SATA PM */
          fis->lbal             == 1 &&
          fis->byte_count_low   == 0x69 &&
          fis->byte_count_high  == 0x96 &&
          (fis->device & ~0x10) == 0))

        /* Treat it as a superset? */
        dev->sata_dev.command_set = ATAPI_COMMAND_SET;
}

void sas_probe_sata(struct asd_sas_port *port)
{
    struct domain_device *dev, *n;

    mutex_lock(&port->ha->disco_mutex);
    list_for_each_entry(dev, &port->disco_list, disco_list_node) {
        if (!dev_is_sata(dev))
            continue;

        ata_sas_async_probe(dev->sata_dev.ap);
    }
    mutex_unlock(&port->ha->disco_mutex);

    list_for_each_entry_safe(dev, n, &port->disco_list, disco_list_node) {
        if (!dev_is_sata(dev))
            continue;

        sas_ata_wait_eh(dev);

        /* if libata could not bring the link up, don't surface
         * the device
         */
        if (ata_dev_disabled(sas_to_ata_dev(dev)))
            sas_fail_probe(dev, __func__, -ENODEV);
    }

}

static bool sas_ata_flush_pm_eh(struct asd_sas_port *port, const char *func)
{
    struct domain_device *dev, *n;
    bool retry = false;

    list_for_each_entry_safe(dev, n, &port->dev_list, dev_list_node) {
        int rc;

        if (!dev_is_sata(dev))
            continue;

        sas_ata_wait_eh(dev);
        rc = dev->sata_dev.pm_result;
        if (rc == -EAGAIN)
            retry = true;
        else if (rc) {
            /* since we don't have a
             * ->port_{suspend|resume} routine in our
             *  ata_port ops, and no entanglements with
             *  acpi, suspend should just be mechanical trip
             *  through eh, catch cases where these
             *  assumptions are invalidated
             */
            WARN_ONCE(1, "failed %s %s error: %d\n", func,
                 dev_name(&dev->rphy->dev), rc);
        }

        /* if libata failed to power manage the device, tear it down */
        if (ata_dev_disabled(sas_to_ata_dev(dev)))
            sas_fail_probe(dev, func, -ENODEV);
    }

    return retry;
}

void sas_suspend_sata(struct asd_sas_port *port)
{
    struct domain_device *dev;

 retry:
    mutex_lock(&port->ha->disco_mutex);
    list_for_each_entry(dev, &port->dev_list, dev_list_node) {
        struct sata_device *sata;

        if (!dev_is_sata(dev))
            continue;

        sata = &dev->sata_dev;
        if (sata->ap->pm_mesg.event == PM_EVENT_SUSPEND)
            continue;

        sata->pm_result = -EIO;
        ata_sas_port_async_suspend(sata->ap, &sata->pm_result);
    }
    mutex_unlock(&port->ha->disco_mutex);

    if (sas_ata_flush_pm_eh(port, __func__))
        goto retry;
}

void sas_resume_sata(struct asd_sas_port *port)
{
    struct domain_device *dev;

 retry:
    mutex_lock(&port->ha->disco_mutex);
    list_for_each_entry(dev, &port->dev_list, dev_list_node) {
        struct sata_device *sata;

        if (!dev_is_sata(dev))
            continue;

        sata = &dev->sata_dev;
        if (sata->ap->pm_mesg.event == PM_EVENT_ON)
            continue;

        sata->pm_result = -EIO;
        ata_sas_port_async_resume(sata->ap, &sata->pm_result);
    }
    mutex_unlock(&port->ha->disco_mutex);

    if (sas_ata_flush_pm_eh(port, __func__))
        goto retry;
}

int sas_discover_sata(struct domain_device *dev)
{
    int res;

    if (dev->dev_type == SATA_PM)
        return -ENODEV;

    sas_get_ata_command_set(dev);
    sas_fill_in_rphy(dev, dev->rphy);

    res = sas_notify_lldd_dev_found(dev);
    if (res)
        return res;

    sas_discover_event(dev->port, DISCE_PROBE);
    return 0;
}

static void async_sas_ata_eh(void *data, async_cookie_t cookie)
{
    struct domain_device *dev = data;
    struct ata_port *ap = dev->sata_dev.ap;
    struct sas_ha_struct *ha = dev->port->ha;

    sas_ata_printk(KERN_DEBUG, dev, "dev error handler\n");
    ata_scsi_port_error_handler(ha->core.shost, ap);
    sas_put_device(dev);
}

void sas_ata_strategy_handler(struct Scsi_Host *shost)
{
    struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(shost);
    ASYNC_DOMAIN_EXCLUSIVE(async);
    int i;

    /* it's ok to defer revalidation events during ata eh, these
     * disks are in one of three states:
     * 1/ present for initial domain discovery, and these
     *    resets will cause bcn flutters
     * 2/ hot removed, we'll discover that after eh fails
     * 3/ hot added after initial discovery, lost the race, and need
     *    to catch the next train.
     */
    sas_disable_revalidation(sas_ha);

    spin_lock_irq(&sas_ha->phy_port_lock);
    for (i = 0; i < sas_ha->num_phys; i++) {
        struct asd_sas_port *port = sas_ha->sas_port[i];
        struct domain_device *dev;

        spin_lock(&port->dev_list_lock);
        list_for_each_entry(dev, &port->dev_list, dev_list_node) {
            if (!dev_is_sata(dev))
                continue;

            /* hold a reference over eh since we may be
             * racing with final remove once all commands
             * are completed
             */
            kref_get(&dev->kref);

            async_schedule_domain(async_sas_ata_eh, dev, &async);
        }
        spin_unlock(&port->dev_list_lock);
    }
    spin_unlock_irq(&sas_ha->phy_port_lock);

    async_synchronize_full_domain(&async);

    sas_enable_revalidation(sas_ha);
}

void sas_ata_eh(struct Scsi_Host *shost, struct list_head *work_q,
        struct list_head *done_q)
{
    struct scsi_cmnd *cmd, *n;
    struct domain_device *eh_dev;

    do {
        LIST_HEAD(sata_q);
        eh_dev = NULL;

        list_for_each_entry_safe(cmd, n, work_q, eh_entry) {
            struct domain_device *ddev = cmd_to_domain_dev(cmd);

            if (!dev_is_sata(ddev) || TO_SAS_TASK(cmd))
                continue;
            if (eh_dev && eh_dev != ddev)
                continue;
            eh_dev = ddev;
            list_move(&cmd->eh_entry, &sata_q);
        }

        if (!list_empty(&sata_q)) {
            struct ata_port *ap = eh_dev->sata_dev.ap;

            sas_ata_printk(KERN_DEBUG, eh_dev, "cmd error handler\n");
            ata_scsi_cmd_error_handler(shost, ap, &sata_q);
            /*
             * ata's error handler may leave the cmd on the list
             * so make sure they don't remain on a stack list
             * about to go out of scope.
             *
             * This looks strange, since the commands are
             * now part of no list, but the next error
             * action will be ata_port_error_handler()
             * which takes no list and sweeps them up
             * anyway from the ata tag array.
             */
            while (!list_empty(&sata_q))
                list_del_init(sata_q.next);
        }
    } while (eh_dev);
}

void sas_ata_schedule_reset(struct domain_device *dev)
{
    struct ata_eh_info *ehi;
    struct ata_port *ap;
    unsigned long flags;

    if (!dev_is_sata(dev))
        return;

    ap = dev->sata_dev.ap;
    ehi = &ap->link.eh_info;

    spin_lock_irqsave(ap->lock, flags);
    ehi->err_mask |= AC_ERR_TIMEOUT;
    ehi->action |= ATA_EH_RESET;
    ata_port_schedule_eh(ap);
    spin_unlock_irqrestore(ap->lock, flags);
}
EXPORT_SYMBOL_GPL(sas_ata_schedule_reset);

void sas_ata_wait_eh(struct domain_device *dev)
{
    struct ata_port *ap;

    if (!dev_is_sata(dev))
        return;

    ap = dev->sata_dev.ap;
    ata_port_wait_eh(ap);
}