// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Support for SATA devices on Serial Attached SCSI (SAS) controllers
 *
 * Copyright (C) 2006 IBM Corporation
 *
 * Written by: Darrick J. Wong <djwong@us.ibm.com>, IBM Corporation
 */

#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:
                pr_warn("%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 == SAS_SAM_STAT_GOOD ||
            (stat->stat == SAS_SAM_STAT_CHECK_CONDITION &&
              dev->sata_dev.class == ATA_DEV_ATAPI)) {
                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) {
                        pr_warn("%s: SAS error 0x%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:
        sas_free_task(task);
}

static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
        __must_hold(ap->lock)
{
        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: we should try to remove that unlock */
        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 ||
            qc->tf.command == ATA_CMD_FPDMA_RECV ||
            qc->tf.command == ATA_CMD_FPDMA_SEND ||
            qc->tf.command == ATA_CMD_NCQ_NON_DATA) {
                /* Need to zero out the tag libata assigned us */
                qc->tf.nsect = 0;
        }

        ata_tf_to_fis(&qc->tf, qc->dev->link->pmp, 1, (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;
                task->data_dir = qc->dma_dir;
        } else if (qc->tf.protocol == ATA_PROT_NODATA) {
                task->data_dir = DMA_NONE;
        } else {
                for_each_sg(qc->sg, sg, qc->n_elem, si)
                        xfer += sg_dma_len(sg);

                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;

        task->ata_task.use_ncq = ata_is_ncq(qc->tf.protocol);
        task->ata_task.dma_xfer = ata_is_dma(qc->tf.protocol);

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

        ret = i->dft->lldd_execute_task(task, GFP_ATOMIC);
        if (ret) {
                pr_debug("lldd_execute_task returned: %d\n", ret);

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

 out:
        spin_lock(ap->lock);
        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 int 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 |= SAS_SATA_DEV;

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

                dev->dev_type = SAS_SATA_DEV;
                res = sas_get_report_phy_sata(dev->parent, phy->phy_id,
                                              &dev->sata_dev.rps_resp);
                if (res) {
                        pr_debug("report phy sata to %016llx:%02d 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));
                dev->sata_dev.class = 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 != SAS_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 SAS_SATA_PENDING:
                return 0;
        case SAS_END_DEVICE:
                if (ex_phy->attached_sata_dev)
                        return sas_ata_clear_pending(dev, ex_phy);
                fallthrough;
        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("%s" SAS_FMT "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);

        *class = dev->sata_dev.class;

        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);
                pr_debug("%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
         */
        pr_warn("%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:
        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 int sas_ata_prereset(struct ata_link *link, unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        struct domain_device *dev = ap->private_data;
        struct sas_phy *local_phy = sas_get_local_phy(dev);
        int res = 0;

        if (!local_phy->enabled || test_bit(SAS_DEV_GONE, &dev->state))
                res = -ENOENT;
        sas_put_local_phy(local_phy);

        return res;
}

static struct ata_port_operations sas_sata_ops = {
        .prereset               = sas_ata_prereset,
        .hardreset              = sas_ata_hard_reset,
        .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 |
                 ATA_FLAG_SAS_HOST | ATA_FLAG_FPDMA_AUX,
        .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_host *ata_host;
        struct ata_port *ap;
        int rc;

        ata_host = kzalloc(sizeof(*ata_host), GFP_KERNEL);
        if (!ata_host)  {
                pr_err("ata host alloc failed.\n");
                return -ENOMEM;
        }

        ata_host_init(ata_host, ha->dev, &sas_sata_ops);

        ap = ata_sas_port_alloc(ata_host, &sata_port_info, shost);
        if (!ap) {
                pr_err("ata_sas_port_alloc failed.\n");
                rc = -ENODEV;
                goto free_host;
        }

        ap->private_data = found_dev;
        ap->cbl = ATA_CBL_SATA;
        ap->scsi_host = shost;
        rc = ata_sas_port_init(ap);
        if (rc)
                goto destroy_port;

        rc = ata_sas_tport_add(ata_host->dev, ap);
        if (rc)
                goto destroy_port;

        found_dev->sata_dev.ata_host = ata_host;
        found_dev->sata_dev.ap = ap;

        return 0;

destroy_port:
        ata_sas_port_destroy(ap);
free_host:
        ata_host_put(ata_host);
        return rc;
}

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) {
                blk_abort_request(scsi_cmd_to_rq(qc->scsicmd));
                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 int sas_get_ata_command_set(struct domain_device *dev)
{
        struct dev_to_host_fis *fis =
                (struct dev_to_host_fis *) dev->frame_rcvd;
        struct ata_taskfile tf;

        if (dev->dev_type == SAS_SATA_PENDING)
                return ATA_DEV_UNKNOWN;

        ata_tf_from_fis((const u8 *)fis, &tf);

        return ata_dev_classify(&tf);
}

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_enabled(sas_to_ata_dev(dev)))
                        sas_fail_probe(dev, __func__, -ENODEV);
        }

}

static void sas_ata_flush_pm_eh(struct asd_sas_port *port, const char *func)
{
        struct domain_device *dev, *n;

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

                sas_ata_wait_eh(dev);

                /* 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);
        }
}

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

        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;

                ata_sas_port_suspend(sata->ap);
        }
        mutex_unlock(&port->ha->disco_mutex);

        sas_ata_flush_pm_eh(port, __func__);
}

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

        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;

                ata_sas_port_resume(sata->ap);
        }
        mutex_unlock(&port->ha->disco_mutex);

        sas_ata_flush_pm_eh(port, __func__);
}

/**
 * sas_discover_sata - discover an STP/SATA domain device
 * @dev: pointer to struct domain_device of interest
 *
 * Devices directly attached to a HA port, have no parents.  All other
 * devices do, and should have their "parent" pointer set appropriately
 * before calling this function.
 */
int sas_discover_sata(struct domain_device *dev)
{
        if (dev->dev_type == SAS_SATA_PM)
                return -ENODEV;

        dev->sata_dev.class = sas_get_ata_command_set(dev);
        sas_fill_in_rphy(dev, dev->rphy);

        return sas_notify_lldd_dev_found(dev);
}

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);
}