libata-eh.c

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/*
 *  libata-eh.c - libata error handling
 *
 *  Maintained by:  Jeff Garzik <[email protected]>
 *              Please ALWAYS copy [email protected]
 *          on emails.
 *
 *  Copyright 2006 Tejun Heo <[email protected]>
 *
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation; either version 2, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 *  USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from http://www.t13.org/ and
 *  http://www.sata-io.org/
 *
 */

#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/export.h>
#include <linux/pci.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include "../scsi/scsi_transport_api.h"

#include <linux/libata.h>

#include "libata.h"

enum {
    /* speed down verdicts */
    ATA_EH_SPDN_NCQ_OFF     = (1 << 0),
    ATA_EH_SPDN_SPEED_DOWN      = (1 << 1),
    ATA_EH_SPDN_FALLBACK_TO_PIO = (1 << 2),
    ATA_EH_SPDN_KEEP_ERRORS     = (1 << 3),

    /* error flags */
    ATA_EFLAG_IS_IO         = (1 << 0),
    ATA_EFLAG_DUBIOUS_XFER      = (1 << 1),
    ATA_EFLAG_OLD_ER                = (1 << 31),

    /* error categories */
    ATA_ECAT_NONE           = 0,
    ATA_ECAT_ATA_BUS        = 1,
    ATA_ECAT_TOUT_HSM       = 2,
    ATA_ECAT_UNK_DEV        = 3,
    ATA_ECAT_DUBIOUS_NONE       = 4,
    ATA_ECAT_DUBIOUS_ATA_BUS    = 5,
    ATA_ECAT_DUBIOUS_TOUT_HSM   = 6,
    ATA_ECAT_DUBIOUS_UNK_DEV    = 7,
    ATA_ECAT_NR         = 8,

    ATA_EH_CMD_DFL_TIMEOUT      =  5000,

    /* always put at least this amount of time between resets */
    ATA_EH_RESET_COOL_DOWN      =  5000,

    /* Waiting in ->prereset can never be reliable.  It's
     * sometimes nice to wait there but it can't be depended upon;
     * otherwise, we wouldn't be resetting.  Just give it enough
     * time for most drives to spin up.
     */
    ATA_EH_PRERESET_TIMEOUT     = 10000,
    ATA_EH_FASTDRAIN_INTERVAL   =  3000,

    ATA_EH_UA_TRIES         = 5,

    /* probe speed down parameters, see ata_eh_schedule_probe() */
    ATA_EH_PROBE_TRIAL_INTERVAL = 60000,    /* 1 min */
    ATA_EH_PROBE_TRIALS     = 2,
};

/* The following table determines how we sequence resets.  Each entry
 * represents timeout for that try.  The first try can be soft or
 * hardreset.  All others are hardreset if available.  In most cases
 * the first reset w/ 10sec timeout should succeed.  Following entries
 * are mostly for error handling, hotplug and retarded devices.
 */
static const unsigned long ata_eh_reset_timeouts[] = {
    10000,  /* most drives spin up by 10sec */
    10000,  /* > 99% working drives spin up before 20sec */
    35000,  /* give > 30 secs of idleness for retarded devices */
     5000,  /* and sweet one last chance */
    ULONG_MAX, /* > 1 min has elapsed, give up */
};

static const unsigned long ata_eh_identify_timeouts[] = {
     5000,  /* covers > 99% of successes and not too boring on failures */
    10000,  /* combined time till here is enough even for media access */
    30000,  /* for true idiots */
    ULONG_MAX,
};

static const unsigned long ata_eh_flush_timeouts[] = {
    15000,  /* be generous with flush */
    15000,  /* ditto */
    30000,  /* and even more generous */
    ULONG_MAX,
};

static const unsigned long ata_eh_other_timeouts[] = {
     5000,  /* same rationale as identify timeout */
    10000,  /* ditto */
    /* but no merciful 30sec for other commands, it just isn't worth it */
    ULONG_MAX,
};

struct ata_eh_cmd_timeout_ent {
    const u8        *commands;
    const unsigned long *timeouts;
};

/* The following table determines timeouts to use for EH internal
 * commands.  Each table entry is a command class and matches the
 * commands the entry applies to and the timeout table to use.
 *
 * On the retry after a command timed out, the next timeout value from
 * the table is used.  If the table doesn't contain further entries,
 * the last value is used.
 *
 * ehc->cmd_timeout_idx keeps track of which timeout to use per
 * command class, so if SET_FEATURES times out on the first try, the
 * next try will use the second timeout value only for that class.
 */
#define CMDS(cmds...)   (const u8 []){ cmds, 0 }
static const struct ata_eh_cmd_timeout_ent
ata_eh_cmd_timeout_table[ATA_EH_CMD_TIMEOUT_TABLE_SIZE] = {
    { .commands = CMDS(ATA_CMD_ID_ATA, ATA_CMD_ID_ATAPI),
      .timeouts = ata_eh_identify_timeouts, },
    { .commands = CMDS(ATA_CMD_READ_NATIVE_MAX, ATA_CMD_READ_NATIVE_MAX_EXT),
      .timeouts = ata_eh_other_timeouts, },
    { .commands = CMDS(ATA_CMD_SET_MAX, ATA_CMD_SET_MAX_EXT),
      .timeouts = ata_eh_other_timeouts, },
    { .commands = CMDS(ATA_CMD_SET_FEATURES),
      .timeouts = ata_eh_other_timeouts, },
    { .commands = CMDS(ATA_CMD_INIT_DEV_PARAMS),
      .timeouts = ata_eh_other_timeouts, },
    { .commands = CMDS(ATA_CMD_FLUSH, ATA_CMD_FLUSH_EXT),
      .timeouts = ata_eh_flush_timeouts },
};
#undef CMDS

static void __ata_port_freeze(struct ata_port *ap);
#ifdef CONFIG_PM
static void ata_eh_handle_port_suspend(struct ata_port *ap);
static void ata_eh_handle_port_resume(struct ata_port *ap);
#else /* CONFIG_PM */
static void ata_eh_handle_port_suspend(struct ata_port *ap)
{ }

static void ata_eh_handle_port_resume(struct ata_port *ap)
{ }
#endif /* CONFIG_PM */

static void __ata_ehi_pushv_desc(struct ata_eh_info *ehi, const char *fmt,
                 va_list args)
{
    ehi->desc_len += vscnprintf(ehi->desc + ehi->desc_len,
                     ATA_EH_DESC_LEN - ehi->desc_len,
                     fmt, args);
}

void __ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
{
    va_list args;

    va_start(args, fmt);
    __ata_ehi_pushv_desc(ehi, fmt, args);
    va_end(args);
}

void ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
{
    va_list args;

    if (ehi->desc_len)
        __ata_ehi_push_desc(ehi, ", ");

    va_start(args, fmt);
    __ata_ehi_pushv_desc(ehi, fmt, args);
    va_end(args);
}

void ata_ehi_clear_desc(struct ata_eh_info *ehi)
{
    ehi->desc[0] = '\0';
    ehi->desc_len = 0;
}

void ata_port_desc(struct ata_port *ap, const char *fmt, ...)
{
    va_list args;

    WARN_ON(!(ap->pflags & ATA_PFLAG_INITIALIZING));

    if (ap->link.eh_info.desc_len)
        __ata_ehi_push_desc(&ap->link.eh_info, " ");

    va_start(args, fmt);
    __ata_ehi_pushv_desc(&ap->link.eh_info, fmt, args);
    va_end(args);
}

#ifdef CONFIG_PCI

void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
            const char *name)
{
    struct pci_dev *pdev = to_pci_dev(ap->host->dev);
    char *type = "";
    unsigned long long start, len;

    if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
        type = "m";
    else if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
        type = "i";

    start = (unsigned long long)pci_resource_start(pdev, bar);
    len = (unsigned long long)pci_resource_len(pdev, bar);

    if (offset < 0)
        ata_port_desc(ap, "%s %s%llu@0x%llx", name, type, len, start);
    else
        ata_port_desc(ap, "%s 0x%llx", name,
                start + (unsigned long long)offset);
}

#endif /* CONFIG_PCI */

static int ata_lookup_timeout_table(u8 cmd)
{
    int i;

    for (i = 0; i < ATA_EH_CMD_TIMEOUT_TABLE_SIZE; i++) {
        const u8 *cur;

        for (cur = ata_eh_cmd_timeout_table[i].commands; *cur; cur++)
            if (*cur == cmd)
                return i;
    }

    return -1;
}

unsigned long ata_internal_cmd_timeout(struct ata_device *dev, u8 cmd)
{
    struct ata_eh_context *ehc = &dev->link->eh_context;
    int ent = ata_lookup_timeout_table(cmd);
    int idx;

    if (ent < 0)
        return ATA_EH_CMD_DFL_TIMEOUT;

    idx = ehc->cmd_timeout_idx[dev->devno][ent];
    return ata_eh_cmd_timeout_table[ent].timeouts[idx];
}

void ata_internal_cmd_timed_out(struct ata_device *dev, u8 cmd)
{
    struct ata_eh_context *ehc = &dev->link->eh_context;
    int ent = ata_lookup_timeout_table(cmd);
    int idx;

    if (ent < 0)
        return;

    idx = ehc->cmd_timeout_idx[dev->devno][ent];
    if (ata_eh_cmd_timeout_table[ent].timeouts[idx + 1] != ULONG_MAX)
        ehc->cmd_timeout_idx[dev->devno][ent]++;
}

static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
                 unsigned int err_mask)
{
    struct ata_ering_entry *ent;

    WARN_ON(!err_mask);

    ering->cursor++;
    ering->cursor %= ATA_ERING_SIZE;

    ent = &ering->ring[ering->cursor];
    ent->eflags = eflags;
    ent->err_mask = err_mask;
    ent->timestamp = get_jiffies_64();
}

static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
{
    struct ata_ering_entry *ent = &ering->ring[ering->cursor];

    if (ent->err_mask)
        return ent;
    return NULL;
}

int ata_ering_map(struct ata_ering *ering,
          int (*map_fn)(struct ata_ering_entry *, void *),
          void *arg)
{
    int idx, rc = 0;
    struct ata_ering_entry *ent;

    idx = ering->cursor;
    do {
        ent = &ering->ring[idx];
        if (!ent->err_mask)
            break;
        rc = map_fn(ent, arg);
        if (rc)
            break;
        idx = (idx - 1 + ATA_ERING_SIZE) % ATA_ERING_SIZE;
    } while (idx != ering->cursor);

    return rc;
}

static int ata_ering_clear_cb(struct ata_ering_entry *ent, void *void_arg)
{
    ent->eflags |= ATA_EFLAG_OLD_ER;
    return 0;
}

static void ata_ering_clear(struct ata_ering *ering)
{
    ata_ering_map(ering, ata_ering_clear_cb, NULL);
}

static unsigned int ata_eh_dev_action(struct ata_device *dev)
{
    struct ata_eh_context *ehc = &dev->link->eh_context;

    return ehc->i.action | ehc->i.dev_action[dev->devno];
}

static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
                struct ata_eh_info *ehi, unsigned int action)
{
    struct ata_device *tdev;

    if (!dev) {
        ehi->action &= ~action;
        ata_for_each_dev(tdev, link, ALL)
            ehi->dev_action[tdev->devno] &= ~action;
    } else {
        /* doesn't make sense for port-wide EH actions */
        WARN_ON(!(action & ATA_EH_PERDEV_MASK));

        /* break ehi->action into ehi->dev_action */
        if (ehi->action & action) {
            ata_for_each_dev(tdev, link, ALL)
                ehi->dev_action[tdev->devno] |=
                    ehi->action & action;
            ehi->action &= ~action;
        }

        /* turn off the specified per-dev action */
        ehi->dev_action[dev->devno] &= ~action;
    }
}

void ata_eh_acquire(struct ata_port *ap)
{
    mutex_lock(&ap->host->eh_mutex);
    WARN_ON_ONCE(ap->host->eh_owner);
    ap->host->eh_owner = current;
}

void ata_eh_release(struct ata_port *ap)
{
    WARN_ON_ONCE(ap->host->eh_owner != current);
    ap->host->eh_owner = NULL;
    mutex_unlock(&ap->host->eh_mutex);
}

enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
{
    struct Scsi_Host *host = cmd->device->host;
    struct ata_port *ap = ata_shost_to_port(host);
    unsigned long flags;
    struct ata_queued_cmd *qc;
    enum blk_eh_timer_return ret;

    DPRINTK("ENTER\n");

    if (ap->ops->error_handler) {
        ret = BLK_EH_NOT_HANDLED;
        goto out;
    }

    ret = BLK_EH_HANDLED;
    spin_lock_irqsave(ap->lock, flags);
    qc = ata_qc_from_tag(ap, ap->link.active_tag);
    if (qc) {
        WARN_ON(qc->scsicmd != cmd);
        qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
        qc->err_mask |= AC_ERR_TIMEOUT;
        ret = BLK_EH_NOT_HANDLED;
    }
    spin_unlock_irqrestore(ap->lock, flags);

 out:
    DPRINTK("EXIT, ret=%d\n", ret);
    return ret;
}

static void ata_eh_unload(struct ata_port *ap)
{
    struct ata_link *link;
    struct ata_device *dev;
    unsigned long flags;

    /* Restore SControl IPM and SPD for the next driver and
     * disable attached devices.
     */
    ata_for_each_link(link, ap, PMP_FIRST) {
        sata_scr_write(link, SCR_CONTROL, link->saved_scontrol & 0xff0);
        ata_for_each_dev(dev, link, ALL)
            ata_dev_disable(dev);
    }

    /* freeze and set UNLOADED */
    spin_lock_irqsave(ap->lock, flags);

    ata_port_freeze(ap);            /* won't be thawed */
    ap->pflags &= ~ATA_PFLAG_EH_PENDING;    /* clear pending from freeze */
    ap->pflags |= ATA_PFLAG_UNLOADED;

    spin_unlock_irqrestore(ap->lock, flags);
}

void ata_scsi_error(struct Scsi_Host *host)
{
    struct ata_port *ap = ata_shost_to_port(host);
    unsigned long flags;
    LIST_HEAD(eh_work_q);

    DPRINTK("ENTER\n");

    spin_lock_irqsave(host->host_lock, flags);
    list_splice_init(&host->eh_cmd_q, &eh_work_q);
    spin_unlock_irqrestore(host->host_lock, flags);

    ata_scsi_cmd_error_handler(host, ap, &eh_work_q);

    /* If we timed raced normal completion and there is nothing to
       recover nr_timedout == 0 why exactly are we doing error recovery ? */
    ata_scsi_port_error_handler(host, ap);

    /* finish or retry handled scmd's and clean up */
    WARN_ON(host->host_failed || !list_empty(&eh_work_q));

    DPRINTK("EXIT\n");
}

void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
                struct list_head *eh_work_q)
{
    int i;
    unsigned long flags;

    /* make sure sff pio task is not running */
    ata_sff_flush_pio_task(ap);

    /* synchronize with host lock and sort out timeouts */

    /* For new EH, all qcs are finished in one of three ways -
     * normal completion, error completion, and SCSI timeout.
     * Both completions can race against SCSI timeout.  When normal
     * completion wins, the qc never reaches EH.  When error
     * completion wins, the qc has ATA_QCFLAG_FAILED set.
     *
     * When SCSI timeout wins, things are a bit more complex.
     * Normal or error completion can occur after the timeout but
     * before this point.  In such cases, both types of
     * completions are honored.  A scmd is determined to have
     * timed out iff its associated qc is active and not failed.
     */
    if (ap->ops->error_handler) {
        struct scsi_cmnd *scmd, *tmp;
        int nr_timedout = 0;

        spin_lock_irqsave(ap->lock, flags);

        /* This must occur under the ap->lock as we don't want
           a polled recovery to race the real interrupt handler

           The lost_interrupt handler checks for any completed but
           non-notified command and completes much like an IRQ handler.

           We then fall into the error recovery code which will treat
           this as if normal completion won the race */

        if (ap->ops->lost_interrupt)
            ap->ops->lost_interrupt(ap);

        list_for_each_entry_safe(scmd, tmp, eh_work_q, eh_entry) {
            struct ata_queued_cmd *qc;

            for (i = 0; i < ATA_MAX_QUEUE; i++) {
                qc = __ata_qc_from_tag(ap, i);
                if (qc->flags & ATA_QCFLAG_ACTIVE &&
                    qc->scsicmd == scmd)
                    break;
            }

            if (i < ATA_MAX_QUEUE) {
                /* the scmd has an associated qc */
                if (!(qc->flags & ATA_QCFLAG_FAILED)) {
                    /* which hasn't failed yet, timeout */
                    qc->err_mask |= AC_ERR_TIMEOUT;
                    qc->flags |= ATA_QCFLAG_FAILED;
                    nr_timedout++;
                }
            } else {
                /* Normal completion occurred after
                 * SCSI timeout but before this point.
                 * Successfully complete it.
                 */
                scmd->retries = scmd->allowed;
                scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
            }
        }

        /* If we have timed out qcs.  They belong to EH from
         * this point but the state of the controller is
         * unknown.  Freeze the port to make sure the IRQ
         * handler doesn't diddle with those qcs.  This must
         * be done atomically w.r.t. setting QCFLAG_FAILED.
         */
        if (nr_timedout)
            __ata_port_freeze(ap);

        spin_unlock_irqrestore(ap->lock, flags);

        /* initialize eh_tries */
        ap->eh_tries = ATA_EH_MAX_TRIES;
    } else
        spin_unlock_wait(ap->lock);

}
EXPORT_SYMBOL(ata_scsi_cmd_error_handler);

void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
{
    unsigned long flags;

    /* invoke error handler */
    if (ap->ops->error_handler) {
        struct ata_link *link;

        /* acquire EH ownership */
        ata_eh_acquire(ap);
 repeat:
        /* kill fast drain timer */
        del_timer_sync(&ap->fastdrain_timer);

        /* process port resume request */
        ata_eh_handle_port_resume(ap);

        /* fetch & clear EH info */
        spin_lock_irqsave(ap->lock, flags);

        ata_for_each_link(link, ap, HOST_FIRST) {
            struct ata_eh_context *ehc = &link->eh_context;
            struct ata_device *dev;

            memset(&link->eh_context, 0, sizeof(link->eh_context));
            link->eh_context.i = link->eh_info;
            memset(&link->eh_info, 0, sizeof(link->eh_info));

            ata_for_each_dev(dev, link, ENABLED) {
                int devno = dev->devno;

                ehc->saved_xfer_mode[devno] = dev->xfer_mode;
                if (ata_ncq_enabled(dev))
                    ehc->saved_ncq_enabled |= 1 << devno;
            }
        }

        ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
        ap->pflags &= ~ATA_PFLAG_EH_PENDING;
        ap->excl_link = NULL;   /* don't maintain exclusion over EH */

        spin_unlock_irqrestore(ap->lock, flags);

        /* invoke EH, skip if unloading or suspended */
        if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
            ap->ops->error_handler(ap);
        else {
            /* if unloading, commence suicide */
            if ((ap->pflags & ATA_PFLAG_UNLOADING) &&
                !(ap->pflags & ATA_PFLAG_UNLOADED))
                ata_eh_unload(ap);
            ata_eh_finish(ap);
        }

        /* process port suspend request */
        ata_eh_handle_port_suspend(ap);

        /* Exception might have happened after ->error_handler
         * recovered the port but before this point.  Repeat
         * EH in such case.
         */
        spin_lock_irqsave(ap->lock, flags);

        if (ap->pflags & ATA_PFLAG_EH_PENDING) {
            if (--ap->eh_tries) {
                spin_unlock_irqrestore(ap->lock, flags);
                goto repeat;
            }
            ata_port_err(ap,
                     "EH pending after %d tries, giving up\n",
                     ATA_EH_MAX_TRIES);
            ap->pflags &= ~ATA_PFLAG_EH_PENDING;
        }

        /* this run is complete, make sure EH info is clear */
        ata_for_each_link(link, ap, HOST_FIRST)
            memset(&link->eh_info, 0, sizeof(link->eh_info));

        /* end eh (clear host_eh_scheduled) while holding
         * ap->lock such that if exception occurs after this
         * point but before EH completion, SCSI midlayer will
         * re-initiate EH.
         */
        ap->ops->end_eh(ap);

        spin_unlock_irqrestore(ap->lock, flags);
        ata_eh_release(ap);
    } else {
        WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
        ap->ops->eng_timeout(ap);
    }

    scsi_eh_flush_done_q(&ap->eh_done_q);

    /* clean up */
    spin_lock_irqsave(ap->lock, flags);

    if (ap->pflags & ATA_PFLAG_LOADING)
        ap->pflags &= ~ATA_PFLAG_LOADING;
    else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
        schedule_delayed_work(&ap->hotplug_task, 0);

    if (ap->pflags & ATA_PFLAG_RECOVERED)
        ata_port_info(ap, "EH complete\n");

    ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);

    /* tell wait_eh that we're done */
    ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
    wake_up_all(&ap->eh_wait_q);

    spin_unlock_irqrestore(ap->lock, flags);
}
EXPORT_SYMBOL_GPL(ata_scsi_port_error_handler);

void ata_port_wait_eh(struct ata_port *ap)
{
    unsigned long flags;
    DEFINE_WAIT(wait);

 retry:
    spin_lock_irqsave(ap->lock, flags);

    while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
        prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
        spin_unlock_irqrestore(ap->lock, flags);
        schedule();
        spin_lock_irqsave(ap->lock, flags);
    }
    finish_wait(&ap->eh_wait_q, &wait);

    spin_unlock_irqrestore(ap->lock, flags);

    /* make sure SCSI EH is complete */
    if (scsi_host_in_recovery(ap->scsi_host)) {
        ata_msleep(ap, 10);
        goto retry;
    }
}
EXPORT_SYMBOL_GPL(ata_port_wait_eh);

static int ata_eh_nr_in_flight(struct ata_port *ap)
{
    unsigned int tag;
    int nr = 0;

    /* count only non-internal commands */
    for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
        if (ata_qc_from_tag(ap, tag))
            nr++;

    return nr;
}

void ata_eh_fastdrain_timerfn(unsigned long arg)
{
    struct ata_port *ap = (void *)arg;
    unsigned long flags;
    int cnt;

    spin_lock_irqsave(ap->lock, flags);

    cnt = ata_eh_nr_in_flight(ap);

    /* are we done? */
    if (!cnt)
        goto out_unlock;

    if (cnt == ap->fastdrain_cnt) {
        unsigned int tag;

        /* No progress during the last interval, tag all
         * in-flight qcs as timed out and freeze the port.
         */
        for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
            struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
            if (qc)
                qc->err_mask |= AC_ERR_TIMEOUT;
        }

        ata_port_freeze(ap);
    } else {
        /* some qcs have finished, give it another chance */
        ap->fastdrain_cnt = cnt;
        ap->fastdrain_timer.expires =
            ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
        add_timer(&ap->fastdrain_timer);
    }

 out_unlock:
    spin_unlock_irqrestore(ap->lock, flags);
}

static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
{
    int cnt;

    /* already scheduled? */
    if (ap->pflags & ATA_PFLAG_EH_PENDING)
        return;

    ap->pflags |= ATA_PFLAG_EH_PENDING;

    if (!fastdrain)
        return;

    /* do we have in-flight qcs? */
    cnt = ata_eh_nr_in_flight(ap);
    if (!cnt)
        return;

    /* activate fast drain */
    ap->fastdrain_cnt = cnt;
    ap->fastdrain_timer.expires =
        ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
    add_timer(&ap->fastdrain_timer);
}

void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
{
    struct ata_port *ap = qc->ap;
    struct request_queue *q = qc->scsicmd->device->request_queue;
    unsigned long flags;

    WARN_ON(!ap->ops->error_handler);

    qc->flags |= ATA_QCFLAG_FAILED;
    ata_eh_set_pending(ap, 1);

    /* The following will fail if timeout has already expired.
     * ata_scsi_error() takes care of such scmds on EH entry.
     * Note that ATA_QCFLAG_FAILED is unconditionally set after
     * this function completes.
     */
    spin_lock_irqsave(q->queue_lock, flags);
    blk_abort_request(qc->scsicmd->request);
    spin_unlock_irqrestore(q->queue_lock, flags);
}

void ata_std_sched_eh(struct ata_port *ap)
{
    WARN_ON(!ap->ops->error_handler);

    if (ap->pflags & ATA_PFLAG_INITIALIZING)
        return;

    ata_eh_set_pending(ap, 1);
    scsi_schedule_eh(ap->scsi_host);

    DPRINTK("port EH scheduled\n");
}
EXPORT_SYMBOL_GPL(ata_std_sched_eh);

void ata_std_end_eh(struct ata_port *ap)
{
    struct Scsi_Host *host = ap->scsi_host;

    host->host_eh_scheduled = 0;
}
EXPORT_SYMBOL(ata_std_end_eh);


void ata_port_schedule_eh(struct ata_port *ap)
{
    /* see: ata_std_sched_eh, unless you know better */
    ap->ops->sched_eh(ap);
}

static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
{
    int tag, nr_aborted = 0;

    WARN_ON(!ap->ops->error_handler);

    /* we're gonna abort all commands, no need for fast drain */
    ata_eh_set_pending(ap, 0);

    for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
        struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);

        if (qc && (!link || qc->dev->link == link)) {
            qc->flags |= ATA_QCFLAG_FAILED;
            ata_qc_complete(qc);
            nr_aborted++;
        }
    }

    if (!nr_aborted)
        ata_port_schedule_eh(ap);

    return nr_aborted;
}

int ata_link_abort(struct ata_link *link)
{
    return ata_do_link_abort(link->ap, link);
}

int ata_port_abort(struct ata_port *ap)
{
    return ata_do_link_abort(ap, NULL);
}

static void __ata_port_freeze(struct ata_port *ap)
{
    WARN_ON(!ap->ops->error_handler);

    if (ap->ops->freeze)
        ap->ops->freeze(ap);

    ap->pflags |= ATA_PFLAG_FROZEN;

    DPRINTK("ata%u port frozen\n", ap->print_id);
}

int ata_port_freeze(struct ata_port *ap)
{
    int nr_aborted;

    WARN_ON(!ap->ops->error_handler);

    __ata_port_freeze(ap);
    nr_aborted = ata_port_abort(ap);

    return nr_aborted;
}

int sata_async_notification(struct ata_port *ap)
{
    u32 sntf;
    int rc;

    if (!(ap->flags & ATA_FLAG_AN))
        return 0;

    rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
    if (rc == 0)
        sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);

    if (!sata_pmp_attached(ap) || rc) {
        /* PMP is not attached or SNTF is not available */
        if (!sata_pmp_attached(ap)) {
            /* PMP is not attached.  Check whether ATAPI
             * AN is configured.  If so, notify media
             * change.
             */
            struct ata_device *dev = ap->link.device;

            if ((dev->class == ATA_DEV_ATAPI) &&
                (dev->flags & ATA_DFLAG_AN))
                ata_scsi_media_change_notify(dev);
            return 0;
        } else {
            /* PMP is attached but SNTF is not available.
             * ATAPI async media change notification is
             * not used.  The PMP must be reporting PHY
             * status change, schedule EH.
             */
            ata_port_schedule_eh(ap);
            return 1;
        }
    } else {
        /* PMP is attached and SNTF is available */
        struct ata_link *link;

        /* check and notify ATAPI AN */
        ata_for_each_link(link, ap, EDGE) {
            if (!(sntf & (1 << link->pmp)))
                continue;

            if ((link->device->class == ATA_DEV_ATAPI) &&
                (link->device->flags & ATA_DFLAG_AN))
                ata_scsi_media_change_notify(link->device);
        }

        /* If PMP is reporting that PHY status of some
         * downstream ports has changed, schedule EH.
         */
        if (sntf & (1 << SATA_PMP_CTRL_PORT)) {
            ata_port_schedule_eh(ap);
            return 1;
        }

        return 0;
    }
}

void ata_eh_freeze_port(struct ata_port *ap)
{
    unsigned long flags;

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

    spin_lock_irqsave(ap->lock, flags);
    __ata_port_freeze(ap);
    spin_unlock_irqrestore(ap->lock, flags);
}

void ata_eh_thaw_port(struct ata_port *ap)
{
    unsigned long flags;

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

    spin_lock_irqsave(ap->lock, flags);

    ap->pflags &= ~ATA_PFLAG_FROZEN;

    if (ap->ops->thaw)
        ap->ops->thaw(ap);

    spin_unlock_irqrestore(ap->lock, flags);

    DPRINTK("ata%u port thawed\n", ap->print_id);
}

static void ata_eh_scsidone(struct scsi_cmnd *scmd)
{
    /* nada */
}

static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
{
    struct ata_port *ap = qc->ap;
    struct scsi_cmnd *scmd = qc->scsicmd;
    unsigned long flags;

    spin_lock_irqsave(ap->lock, flags);
    qc->scsidone = ata_eh_scsidone;
    __ata_qc_complete(qc);
    WARN_ON(ata_tag_valid(qc->tag));
    spin_unlock_irqrestore(ap->lock, flags);

    scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
}

void ata_eh_qc_complete(struct ata_queued_cmd *qc)
{
    struct scsi_cmnd *scmd = qc->scsicmd;
    scmd->retries = scmd->allowed;
    __ata_eh_qc_complete(qc);
}

void ata_eh_qc_retry(struct ata_queued_cmd *qc)
{
    struct scsi_cmnd *scmd = qc->scsicmd;
    if (!qc->err_mask && scmd->retries)
        scmd->retries--;
    __ata_eh_qc_complete(qc);
}

void ata_dev_disable(struct ata_device *dev)
{
    if (!ata_dev_enabled(dev))
        return;

    if (ata_msg_drv(dev->link->ap))
        ata_dev_warn(dev, "disabled\n");
    ata_acpi_on_disable(dev);
    ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);
    dev->class++;

    /* From now till the next successful probe, ering is used to
     * track probe failures.  Clear accumulated device error info.
     */
    ata_ering_clear(&dev->ering);
}

void ata_eh_detach_dev(struct ata_device *dev)
{
    struct ata_link *link = dev->link;
    struct ata_port *ap = link->ap;
    struct ata_eh_context *ehc = &link->eh_context;
    unsigned long flags;

    ata_dev_disable(dev);

    spin_lock_irqsave(ap->lock, flags);

    dev->flags &= ~ATA_DFLAG_DETACH;

    if (ata_scsi_offline_dev(dev)) {
        dev->flags |= ATA_DFLAG_DETACHED;
        ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
    }

    /* clear per-dev EH info */
    ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
    ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
    ehc->saved_xfer_mode[dev->devno] = 0;
    ehc->saved_ncq_enabled &= ~(1 << dev->devno);

    spin_unlock_irqrestore(ap->lock, flags);
}

void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
            unsigned int action)
{
    struct ata_port *ap = link->ap;
    struct ata_eh_info *ehi = &link->eh_info;
    struct ata_eh_context *ehc = &link->eh_context;
    unsigned long flags;

    spin_lock_irqsave(ap->lock, flags);

    ata_eh_clear_action(link, dev, ehi, action);

    /* About to take EH action, set RECOVERED.  Ignore actions on
     * slave links as master will do them again.
     */
    if (!(ehc->i.flags & ATA_EHI_QUIET) && link != ap->slave_link)
        ap->pflags |= ATA_PFLAG_RECOVERED;

    spin_unlock_irqrestore(ap->lock, flags);
}

void ata_eh_done(struct ata_link *link, struct ata_device *dev,
         unsigned int action)
{
    struct ata_eh_context *ehc = &link->eh_context;

    ata_eh_clear_action(link, dev, &ehc->i, action);
}

static const char *ata_err_string(unsigned int err_mask)
{
    if (err_mask & AC_ERR_HOST_BUS)
        return "host bus error";
    if (err_mask & AC_ERR_ATA_BUS)
        return "ATA bus error";
    if (err_mask & AC_ERR_TIMEOUT)
        return "timeout";
    if (err_mask & AC_ERR_HSM)
        return "HSM violation";
    if (err_mask & AC_ERR_SYSTEM)
        return "internal error";
    if (err_mask & AC_ERR_MEDIA)
        return "media error";
    if (err_mask & AC_ERR_INVALID)
        return "invalid argument";
    if (err_mask & AC_ERR_DEV)
        return "device error";
    return "unknown error";
}

unsigned int ata_read_log_page(struct ata_device *dev, u8 log,
                   u8 page, void *buf, unsigned int sectors)
{
    struct ata_taskfile tf;
    unsigned int err_mask;

    DPRINTK("read log page - log 0x%x, page 0x%x\n", log, page);

    ata_tf_init(dev, &tf);
    tf.command = ATA_CMD_READ_LOG_EXT;
    tf.lbal = log;
    tf.lbam = page;
    tf.nsect = sectors;
    tf.hob_nsect = sectors >> 8;
    tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_LBA48 | ATA_TFLAG_DEVICE;
    tf.protocol = ATA_PROT_PIO;

    err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
                     buf, sectors * ATA_SECT_SIZE, 0);

    DPRINTK("EXIT, err_mask=%x\n", err_mask);
    return err_mask;
}

static int ata_eh_read_log_10h(struct ata_device *dev,
                   int *tag, struct ata_taskfile *tf)
{
    u8 *buf = dev->link->ap->sector_buf;
    unsigned int err_mask;
    u8 csum;
    int i;

    err_mask = ata_read_log_page(dev, ATA_LOG_SATA_NCQ, 0, buf, 1);
    if (err_mask)
        return -EIO;

    csum = 0;
    for (i = 0; i < ATA_SECT_SIZE; i++)
        csum += buf[i];
    if (csum)
        ata_dev_warn(dev, "invalid checksum 0x%x on log page 10h\n",
                 csum);

    if (buf[0] & 0x80)
        return -ENOENT;

    *tag = buf[0] & 0x1f;

    tf->command = buf[2];
    tf->feature = buf[3];
    tf->lbal = buf[4];
    tf->lbam = buf[5];
    tf->lbah = buf[6];
    tf->device = buf[7];
    tf->hob_lbal = buf[8];
    tf->hob_lbam = buf[9];
    tf->hob_lbah = buf[10];
    tf->nsect = buf[12];
    tf->hob_nsect = buf[13];

    return 0;
}

static unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
{
    u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
    struct ata_taskfile tf;
    unsigned int err_mask;

    ata_tf_init(dev, &tf);

    tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
    tf.command = ATA_CMD_PACKET;
    tf.protocol = ATAPI_PROT_NODATA;

    err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
    if (err_mask == AC_ERR_DEV)
        *r_sense_key = tf.feature >> 4;
    return err_mask;
}

static unsigned int atapi_eh_request_sense(struct ata_device *dev,
                       u8 *sense_buf, u8 dfl_sense_key)
{
    u8 cdb[ATAPI_CDB_LEN] =
        { REQUEST_SENSE, 0, 0, 0, SCSI_SENSE_BUFFERSIZE, 0 };
    struct ata_port *ap = dev->link->ap;
    struct ata_taskfile tf;

    DPRINTK("ATAPI request sense\n");

    /* FIXME: is this needed? */
    memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);

    /* initialize sense_buf with the error register,
     * for the case where they are -not- overwritten
     */
    sense_buf[0] = 0x70;
    sense_buf[2] = dfl_sense_key;

    /* some devices time out if garbage left in tf */
    ata_tf_init(dev, &tf);

    tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
    tf.command = ATA_CMD_PACKET;

    /* is it pointless to prefer PIO for "safety reasons"? */
    if (ap->flags & ATA_FLAG_PIO_DMA) {
        tf.protocol = ATAPI_PROT_DMA;
        tf.feature |= ATAPI_PKT_DMA;
    } else {
        tf.protocol = ATAPI_PROT_PIO;
        tf.lbam = SCSI_SENSE_BUFFERSIZE;
        tf.lbah = 0;
    }

    return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
                 sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
}

static void ata_eh_analyze_serror(struct ata_link *link)
{
    struct ata_eh_context *ehc = &link->eh_context;
    u32 serror = ehc->i.serror;
    unsigned int err_mask = 0, action = 0;
    u32 hotplug_mask;

    if (serror & (SERR_PERSISTENT | SERR_DATA)) {
        err_mask |= AC_ERR_ATA_BUS;
        action |= ATA_EH_RESET;
    }
    if (serror & SERR_PROTOCOL) {
        err_mask |= AC_ERR_HSM;
        action |= ATA_EH_RESET;
    }
    if (serror & SERR_INTERNAL) {
        err_mask |= AC_ERR_SYSTEM;
        action |= ATA_EH_RESET;
    }

    /* Determine whether a hotplug event has occurred.  Both
     * SError.N/X are considered hotplug events for enabled or
     * host links.  For disabled PMP links, only N bit is
     * considered as X bit is left at 1 for link plugging.
     */
    if (link->lpm_policy > ATA_LPM_MAX_POWER)
        hotplug_mask = 0;   /* hotplug doesn't work w/ LPM */
    else if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
        hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
    else
        hotplug_mask = SERR_PHYRDY_CHG;

    if (serror & hotplug_mask)
        ata_ehi_hotplugged(&ehc->i);

    ehc->i.err_mask |= err_mask;
    ehc->i.action |= action;
}

void ata_eh_analyze_ncq_error(struct ata_link *link)
{
    struct ata_port *ap = link->ap;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_device *dev = link->device;
    struct ata_queued_cmd *qc;
    struct ata_taskfile tf;
    int tag, rc;

    /* if frozen, we can't do much */
    if (ap->pflags & ATA_PFLAG_FROZEN)
        return;

    /* is it NCQ device error? */
    if (!link->sactive || !(ehc->i.err_mask & AC_ERR_DEV))
        return;

    /* has LLDD analyzed already? */
    for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
        qc = __ata_qc_from_tag(ap, tag);

        if (!(qc->flags & ATA_QCFLAG_FAILED))
            continue;

        if (qc->err_mask)
            return;
    }

    /* okay, this error is ours */
    memset(&tf, 0, sizeof(tf));
    rc = ata_eh_read_log_10h(dev, &tag, &tf);
    if (rc) {
        ata_link_err(link, "failed to read log page 10h (errno=%d)\n",
                 rc);
        return;
    }

    if (!(link->sactive & (1 << tag))) {
        ata_link_err(link, "log page 10h reported inactive tag %d\n",
                 tag);
        return;
    }

    /* we've got the perpetrator, condemn it */
    qc = __ata_qc_from_tag(ap, tag);
    memcpy(&qc->result_tf, &tf, sizeof(tf));
    qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
    qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
    ehc->i.err_mask &= ~AC_ERR_DEV;
}

static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
                      const struct ata_taskfile *tf)
{
    unsigned int tmp, action = 0;
    u8 stat = tf->command, err = tf->feature;

    if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
        qc->err_mask |= AC_ERR_HSM;
        return ATA_EH_RESET;
    }

    if (stat & (ATA_ERR | ATA_DF))
        qc->err_mask |= AC_ERR_DEV;
    else
        return 0;

    switch (qc->dev->class) {
    case ATA_DEV_ATA:
        if (err & ATA_ICRC)
            qc->err_mask |= AC_ERR_ATA_BUS;
        if (err & ATA_UNC)
            qc->err_mask |= AC_ERR_MEDIA;
        if (err & ATA_IDNF)
            qc->err_mask |= AC_ERR_INVALID;
        break;

    case ATA_DEV_ATAPI:
        if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
            tmp = atapi_eh_request_sense(qc->dev,
                        qc->scsicmd->sense_buffer,
                        qc->result_tf.feature >> 4);
            if (!tmp) {
                /* ATA_QCFLAG_SENSE_VALID is used to
                 * tell atapi_qc_complete() that sense
                 * data is already valid.
                 *
                 * TODO: interpret sense data and set
                 * appropriate err_mask.
                 */
                qc->flags |= ATA_QCFLAG_SENSE_VALID;
            } else
                qc->err_mask |= tmp;
        }
    }

    if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
        action |= ATA_EH_RESET;

    return action;
}

static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
                   int *xfer_ok)
{
    int base = 0;

    if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
        *xfer_ok = 1;

    if (!*xfer_ok)
        base = ATA_ECAT_DUBIOUS_NONE;

    if (err_mask & AC_ERR_ATA_BUS)
        return base + ATA_ECAT_ATA_BUS;

    if (err_mask & AC_ERR_TIMEOUT)
        return base + ATA_ECAT_TOUT_HSM;

    if (eflags & ATA_EFLAG_IS_IO) {
        if (err_mask & AC_ERR_HSM)
            return base + ATA_ECAT_TOUT_HSM;
        if ((err_mask &
             (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
            return base + ATA_ECAT_UNK_DEV;
    }

    return 0;
}

struct speed_down_verdict_arg {
    u64 since;
    int xfer_ok;
    int nr_errors[ATA_ECAT_NR];
};

static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
{
    struct speed_down_verdict_arg *arg = void_arg;
    int cat;

    if ((ent->eflags & ATA_EFLAG_OLD_ER) || (ent->timestamp < arg->since))
        return -1;

    cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
                      &arg->xfer_ok);
    arg->nr_errors[cat]++;

    return 0;
}

static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
{
    const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
    u64 j64 = get_jiffies_64();
    struct speed_down_verdict_arg arg;
    unsigned int verdict = 0;

    /* scan past 5 mins of error history */
    memset(&arg, 0, sizeof(arg));
    arg.since = j64 - min(j64, j5mins);
    ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);

    if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
        arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
        verdict |= ATA_EH_SPDN_SPEED_DOWN |
            ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;

    if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
        arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
        verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;

    if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
        arg.nr_errors[ATA_ECAT_TOUT_HSM] +
        arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
        verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;

    /* scan past 10 mins of error history */
    memset(&arg, 0, sizeof(arg));
    arg.since = j64 - min(j64, j10mins);
    ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);

    if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
        arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
        verdict |= ATA_EH_SPDN_NCQ_OFF;

    if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
        arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
        arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
        verdict |= ATA_EH_SPDN_SPEED_DOWN;

    return verdict;
}

static unsigned int ata_eh_speed_down(struct ata_device *dev,
                unsigned int eflags, unsigned int err_mask)
{
    struct ata_link *link = ata_dev_phys_link(dev);
    int xfer_ok = 0;
    unsigned int verdict;
    unsigned int action = 0;

    /* don't bother if Cat-0 error */
    if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
        return 0;

    /* record error and determine whether speed down is necessary */
    ata_ering_record(&dev->ering, eflags, err_mask);
    verdict = ata_eh_speed_down_verdict(dev);

    /* turn off NCQ? */
    if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
        (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
               ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
        dev->flags |= ATA_DFLAG_NCQ_OFF;
        ata_dev_warn(dev, "NCQ disabled due to excessive errors\n");
        goto done;
    }

    /* speed down? */
    if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
        /* speed down SATA link speed if possible */
        if (sata_down_spd_limit(link, 0) == 0) {
            action |= ATA_EH_RESET;
            goto done;
        }

        /* lower transfer mode */
        if (dev->spdn_cnt < 2) {
            static const int dma_dnxfer_sel[] =
                { ATA_DNXFER_DMA, ATA_DNXFER_40C };
            static const int pio_dnxfer_sel[] =
                { ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
            int sel;

            if (dev->xfer_shift != ATA_SHIFT_PIO)
                sel = dma_dnxfer_sel[dev->spdn_cnt];
            else
                sel = pio_dnxfer_sel[dev->spdn_cnt];

            dev->spdn_cnt++;

            if (ata_down_xfermask_limit(dev, sel) == 0) {
                action |= ATA_EH_RESET;
                goto done;
            }
        }
    }

    /* Fall back to PIO?  Slowing down to PIO is meaningless for
     * SATA ATA devices.  Consider it only for PATA and SATAPI.
     */
    if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
        (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
        (dev->xfer_shift != ATA_SHIFT_PIO)) {
        if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
            dev->spdn_cnt = 0;
            action |= ATA_EH_RESET;
            goto done;
        }
    }

    return 0;
 done:
    /* device has been slowed down, blow error history */
    if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
        ata_ering_clear(&dev->ering);
    return action;
}

static inline int ata_eh_worth_retry(struct ata_queued_cmd *qc)
{
    if (qc->flags & AC_ERR_MEDIA)
        return 0;   /* don't retry media errors */
    if (qc->flags & ATA_QCFLAG_IO)
        return 1;   /* otherwise retry anything from fs stack */
    if (qc->err_mask & AC_ERR_INVALID)
        return 0;   /* don't retry these */
    return qc->err_mask != AC_ERR_DEV;  /* retry if not dev error */
}

static void ata_eh_link_autopsy(struct ata_link *link)
{
    struct ata_port *ap = link->ap;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_device *dev;
    unsigned int all_err_mask = 0, eflags = 0;
    int tag;
    u32 serror;
    int rc;

    DPRINTK("ENTER\n");

    if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
        return;

    /* obtain and analyze SError */
    rc = sata_scr_read(link, SCR_ERROR, &serror);
    if (rc == 0) {
        ehc->i.serror |= serror;
        ata_eh_analyze_serror(link);
    } else if (rc != -EOPNOTSUPP) {
        /* SError read failed, force reset and probing */
        ehc->i.probe_mask |= ATA_ALL_DEVICES;
        ehc->i.action |= ATA_EH_RESET;
        ehc->i.err_mask |= AC_ERR_OTHER;
    }

    /* analyze NCQ failure */
    ata_eh_analyze_ncq_error(link);

    /* any real error trumps AC_ERR_OTHER */
    if (ehc->i.err_mask & ~AC_ERR_OTHER)
        ehc->i.err_mask &= ~AC_ERR_OTHER;

    all_err_mask |= ehc->i.err_mask;

    for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
        struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);

        if (!(qc->flags & ATA_QCFLAG_FAILED) ||
            ata_dev_phys_link(qc->dev) != link)
            continue;

        /* inherit upper level err_mask */
        qc->err_mask |= ehc->i.err_mask;

        /* analyze TF */
        ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);

        /* DEV errors are probably spurious in case of ATA_BUS error */
        if (qc->err_mask & AC_ERR_ATA_BUS)
            qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
                      AC_ERR_INVALID);

        /* any real error trumps unknown error */
        if (qc->err_mask & ~AC_ERR_OTHER)
            qc->err_mask &= ~AC_ERR_OTHER;

        /* SENSE_VALID trumps dev/unknown error and revalidation */
        if (qc->flags & ATA_QCFLAG_SENSE_VALID)
            qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);

        /* determine whether the command is worth retrying */
        if (ata_eh_worth_retry(qc))
            qc->flags |= ATA_QCFLAG_RETRY;

        /* accumulate error info */
        ehc->i.dev = qc->dev;
        all_err_mask |= qc->err_mask;
        if (qc->flags & ATA_QCFLAG_IO)
            eflags |= ATA_EFLAG_IS_IO;
    }

    /* enforce default EH actions */
    if (ap->pflags & ATA_PFLAG_FROZEN ||
        all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
        ehc->i.action |= ATA_EH_RESET;
    else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
         (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
        ehc->i.action |= ATA_EH_REVALIDATE;

    /* If we have offending qcs and the associated failed device,
     * perform per-dev EH action only on the offending device.
     */
    if (ehc->i.dev) {
        ehc->i.dev_action[ehc->i.dev->devno] |=
            ehc->i.action & ATA_EH_PERDEV_MASK;
        ehc->i.action &= ~ATA_EH_PERDEV_MASK;
    }

    /* propagate timeout to host link */
    if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
        ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;

    /* record error and consider speeding down */
    dev = ehc->i.dev;
    if (!dev && ((ata_link_max_devices(link) == 1 &&
              ata_dev_enabled(link->device))))
        dev = link->device;

    if (dev) {
        if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
            eflags |= ATA_EFLAG_DUBIOUS_XFER;
        ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
    }

    DPRINTK("EXIT\n");
}

void ata_eh_autopsy(struct ata_port *ap)
{
    struct ata_link *link;

    ata_for_each_link(link, ap, EDGE)
        ata_eh_link_autopsy(link);

    /* Handle the frigging slave link.  Autopsy is done similarly
     * but actions and flags are transferred over to the master
     * link and handled from there.
     */
    if (ap->slave_link) {
        struct ata_eh_context *mehc = &ap->link.eh_context;
        struct ata_eh_context *sehc = &ap->slave_link->eh_context;

        /* transfer control flags from master to slave */
        sehc->i.flags |= mehc->i.flags & ATA_EHI_TO_SLAVE_MASK;

        /* perform autopsy on the slave link */
        ata_eh_link_autopsy(ap->slave_link);

        /* transfer actions from slave to master and clear slave */
        ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
        mehc->i.action      |= sehc->i.action;
        mehc->i.dev_action[1]   |= sehc->i.dev_action[1];
        mehc->i.flags       |= sehc->i.flags;
        ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
    }

    /* Autopsy of fanout ports can affect host link autopsy.
     * Perform host link autopsy last.
     */
    if (sata_pmp_attached(ap))
        ata_eh_link_autopsy(&ap->link);
}

const char *ata_get_cmd_descript(u8 command)
{
#ifdef CONFIG_ATA_VERBOSE_ERROR
    static const struct
    {
        u8 command;
        const char *text;
    } cmd_descr[] = {
        { ATA_CMD_DEV_RESET,        "DEVICE RESET" },
        { ATA_CMD_CHK_POWER,        "CHECK POWER MODE" },
        { ATA_CMD_STANDBY,      "STANDBY" },
        { ATA_CMD_IDLE,         "IDLE" },
        { ATA_CMD_EDD,          "EXECUTE DEVICE DIAGNOSTIC" },
        { ATA_CMD_DOWNLOAD_MICRO,       "DOWNLOAD MICROCODE" },
        { ATA_CMD_NOP,          "NOP" },
        { ATA_CMD_FLUSH,        "FLUSH CACHE" },
        { ATA_CMD_FLUSH_EXT,        "FLUSH CACHE EXT" },
        { ATA_CMD_ID_ATA,       "IDENTIFY DEVICE" },
        { ATA_CMD_ID_ATAPI,         "IDENTIFY PACKET DEVICE" },
        { ATA_CMD_SERVICE,      "SERVICE" },
        { ATA_CMD_READ,         "READ DMA" },
        { ATA_CMD_READ_EXT,         "READ DMA EXT" },
        { ATA_CMD_READ_QUEUED,      "READ DMA QUEUED" },
        { ATA_CMD_READ_STREAM_EXT,  "READ STREAM EXT" },
        { ATA_CMD_READ_STREAM_DMA_EXT,  "READ STREAM DMA EXT" },
        { ATA_CMD_WRITE,        "WRITE DMA" },
        { ATA_CMD_WRITE_EXT,        "WRITE DMA EXT" },
        { ATA_CMD_WRITE_QUEUED,     "WRITE DMA QUEUED EXT" },
        { ATA_CMD_WRITE_STREAM_EXT,     "WRITE STREAM EXT" },
        { ATA_CMD_WRITE_STREAM_DMA_EXT, "WRITE STREAM DMA EXT" },
        { ATA_CMD_WRITE_FUA_EXT,    "WRITE DMA FUA EXT" },
        { ATA_CMD_WRITE_QUEUED_FUA_EXT, "WRITE DMA QUEUED FUA EXT" },
        { ATA_CMD_FPDMA_READ,       "READ FPDMA QUEUED" },
        { ATA_CMD_FPDMA_WRITE,      "WRITE FPDMA QUEUED" },
        { ATA_CMD_PIO_READ,     "READ SECTOR(S)" },
        { ATA_CMD_PIO_READ_EXT,     "READ SECTOR(S) EXT" },
        { ATA_CMD_PIO_WRITE,        "WRITE SECTOR(S)" },
        { ATA_CMD_PIO_WRITE_EXT,    "WRITE SECTOR(S) EXT" },
        { ATA_CMD_READ_MULTI,       "READ MULTIPLE" },
        { ATA_CMD_READ_MULTI_EXT,   "READ MULTIPLE EXT" },
        { ATA_CMD_WRITE_MULTI,      "WRITE MULTIPLE" },
        { ATA_CMD_WRITE_MULTI_EXT,  "WRITE MULTIPLE EXT" },
        { ATA_CMD_WRITE_MULTI_FUA_EXT,  "WRITE MULTIPLE FUA EXT" },
        { ATA_CMD_SET_FEATURES,     "SET FEATURES" },
        { ATA_CMD_SET_MULTI,        "SET MULTIPLE MODE" },
        { ATA_CMD_VERIFY,       "READ VERIFY SECTOR(S)" },
        { ATA_CMD_VERIFY_EXT,       "READ VERIFY SECTOR(S) EXT" },
        { ATA_CMD_WRITE_UNCORR_EXT, "WRITE UNCORRECTABLE EXT" },
        { ATA_CMD_STANDBYNOW1,      "STANDBY IMMEDIATE" },
        { ATA_CMD_IDLEIMMEDIATE,    "IDLE IMMEDIATE" },
        { ATA_CMD_SLEEP,        "SLEEP" },
        { ATA_CMD_INIT_DEV_PARAMS,  "INITIALIZE DEVICE PARAMETERS" },
        { ATA_CMD_READ_NATIVE_MAX,  "READ NATIVE MAX ADDRESS" },
        { ATA_CMD_READ_NATIVE_MAX_EXT,  "READ NATIVE MAX ADDRESS EXT" },
        { ATA_CMD_SET_MAX,      "SET MAX ADDRESS" },
        { ATA_CMD_SET_MAX_EXT,      "SET MAX ADDRESS EXT" },
        { ATA_CMD_READ_LOG_EXT,     "READ LOG EXT" },
        { ATA_CMD_WRITE_LOG_EXT,    "WRITE LOG EXT" },
        { ATA_CMD_READ_LOG_DMA_EXT, "READ LOG DMA EXT" },
        { ATA_CMD_WRITE_LOG_DMA_EXT,    "WRITE LOG DMA EXT" },
        { ATA_CMD_TRUSTED_RCV,      "TRUSTED RECEIVE" },
        { ATA_CMD_TRUSTED_RCV_DMA,  "TRUSTED RECEIVE DMA" },
        { ATA_CMD_TRUSTED_SND,      "TRUSTED SEND" },
        { ATA_CMD_TRUSTED_SND_DMA,  "TRUSTED SEND DMA" },
        { ATA_CMD_PMP_READ,     "READ BUFFER" },
        { ATA_CMD_PMP_WRITE,        "WRITE BUFFER" },
        { ATA_CMD_CONF_OVERLAY,     "DEVICE CONFIGURATION OVERLAY" },
        { ATA_CMD_SEC_SET_PASS,     "SECURITY SET PASSWORD" },
        { ATA_CMD_SEC_UNLOCK,       "SECURITY UNLOCK" },
        { ATA_CMD_SEC_ERASE_PREP,   "SECURITY ERASE PREPARE" },
        { ATA_CMD_SEC_ERASE_UNIT,   "SECURITY ERASE UNIT" },
        { ATA_CMD_SEC_FREEZE_LOCK,  "SECURITY FREEZE LOCK" },
        { ATA_CMD_SEC_DISABLE_PASS, "SECURITY DISABLE PASSWORD" },
        { ATA_CMD_CONFIG_STREAM,    "CONFIGURE STREAM" },
        { ATA_CMD_SMART,        "SMART" },
        { ATA_CMD_MEDIA_LOCK,       "DOOR LOCK" },
        { ATA_CMD_MEDIA_UNLOCK,     "DOOR UNLOCK" },
        { ATA_CMD_DSM,          "DATA SET MANAGEMENT" },
        { ATA_CMD_CHK_MED_CRD_TYP,  "CHECK MEDIA CARD TYPE" },
        { ATA_CMD_CFA_REQ_EXT_ERR,  "CFA REQUEST EXTENDED ERROR" },
        { ATA_CMD_CFA_WRITE_NE,     "CFA WRITE SECTORS WITHOUT ERASE" },
        { ATA_CMD_CFA_TRANS_SECT,   "CFA TRANSLATE SECTOR" },
        { ATA_CMD_CFA_ERASE,        "CFA ERASE SECTORS" },
        { ATA_CMD_CFA_WRITE_MULT_NE,    "CFA WRITE MULTIPLE WITHOUT ERASE" },
        { ATA_CMD_READ_LONG,        "READ LONG (with retries)" },
        { ATA_CMD_READ_LONG_ONCE,   "READ LONG (without retries)" },
        { ATA_CMD_WRITE_LONG,       "WRITE LONG (with retries)" },
        { ATA_CMD_WRITE_LONG_ONCE,  "WRITE LONG (without retries)" },
        { ATA_CMD_RESTORE,      "RECALIBRATE" },
        { 0,                NULL } /* terminate list */
    };

    unsigned int i;
    for (i = 0; cmd_descr[i].text; i++)
        if (cmd_descr[i].command == command)
            return cmd_descr[i].text;
#endif

    return NULL;
}

static void ata_eh_link_report(struct ata_link *link)
{
    struct ata_port *ap = link->ap;
    struct ata_eh_context *ehc = &link->eh_context;
    const char *frozen, *desc;
    char tries_buf[6];
    int tag, nr_failed = 0;

    if (ehc->i.flags & ATA_EHI_QUIET)
        return;

    desc = NULL;
    if (ehc->i.desc[0] != '\0')
        desc = ehc->i.desc;

    for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
        struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);

        if (!(qc->flags & ATA_QCFLAG_FAILED) ||
            ata_dev_phys_link(qc->dev) != link ||
            ((qc->flags & ATA_QCFLAG_QUIET) &&
             qc->err_mask == AC_ERR_DEV))
            continue;
        if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
            continue;

        nr_failed++;
    }

    if (!nr_failed && !ehc->i.err_mask)
        return;

    frozen = "";
    if (ap->pflags & ATA_PFLAG_FROZEN)
        frozen = " frozen";

    memset(tries_buf, 0, sizeof(tries_buf));
    if (ap->eh_tries < ATA_EH_MAX_TRIES)
        snprintf(tries_buf, sizeof(tries_buf) - 1, " t%d",
             ap->eh_tries);

    if (ehc->i.dev) {
        ata_dev_err(ehc->i.dev, "exception Emask 0x%x "
                "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
                ehc->i.err_mask, link->sactive, ehc->i.serror,
                ehc->i.action, frozen, tries_buf);
        if (desc)
            ata_dev_err(ehc->i.dev, "%s\n", desc);
    } else {
        ata_link_err(link, "exception Emask 0x%x "
                 "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
                 ehc->i.err_mask, link->sactive, ehc->i.serror,
                 ehc->i.action, frozen, tries_buf);
        if (desc)
            ata_link_err(link, "%s\n", desc);
    }

#ifdef CONFIG_ATA_VERBOSE_ERROR
    if (ehc->i.serror)
        ata_link_err(link,
          "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
          ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
          ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
          ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
          ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
          ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
          ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
          ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
          ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
          ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
          ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
          ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
          ehc->i.serror & SERR_CRC ? "BadCRC " : "",
          ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
          ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
          ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
          ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
          ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
#endif

    for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
        struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
        struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
        const u8 *cdb = qc->cdb;
        char data_buf[20] = "";
        char cdb_buf[70] = "";

        if (!(qc->flags & ATA_QCFLAG_FAILED) ||
            ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
            continue;

        if (qc->dma_dir != DMA_NONE) {
            static const char *dma_str[] = {
                [DMA_BIDIRECTIONAL] = "bidi",
                [DMA_TO_DEVICE]     = "out",
                [DMA_FROM_DEVICE]   = "in",
            };
            static const char *prot_str[] = {
                [ATA_PROT_PIO]      = "pio",
                [ATA_PROT_DMA]      = "dma",
                [ATA_PROT_NCQ]      = "ncq",
                [ATAPI_PROT_PIO]    = "pio",
                [ATAPI_PROT_DMA]    = "dma",
            };

            snprintf(data_buf, sizeof(data_buf), " %s %u %s",
                 prot_str[qc->tf.protocol], qc->nbytes,
                 dma_str[qc->dma_dir]);
        }

        if (ata_is_atapi(qc->tf.protocol)) {
            if (qc->scsicmd)
                scsi_print_command(qc->scsicmd);
            else
                snprintf(cdb_buf, sizeof(cdb_buf),
                 "cdb %02x %02x %02x %02x %02x %02x %02x %02x  "
                 "%02x %02x %02x %02x %02x %02x %02x %02x\n         ",
                 cdb[0], cdb[1], cdb[2], cdb[3],
                 cdb[4], cdb[5], cdb[6], cdb[7],
                 cdb[8], cdb[9], cdb[10], cdb[11],
                 cdb[12], cdb[13], cdb[14], cdb[15]);
        } else {
            const char *descr = ata_get_cmd_descript(cmd->command);
            if (descr)
                ata_dev_err(qc->dev, "failed command: %s\n",
                        descr);
        }

        ata_dev_err(qc->dev,
            "cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
            "tag %d%s\n         %s"
            "res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
            "Emask 0x%x (%s)%s\n",
            cmd->command, cmd->feature, cmd->nsect,
            cmd->lbal, cmd->lbam, cmd->lbah,
            cmd->hob_feature, cmd->hob_nsect,
            cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
            cmd->device, qc->tag, data_buf, cdb_buf,
            res->command, res->feature, res->nsect,
            res->lbal, res->lbam, res->lbah,
            res->hob_feature, res->hob_nsect,
            res->hob_lbal, res->hob_lbam, res->hob_lbah,
            res->device, qc->err_mask, ata_err_string(qc->err_mask),
            qc->err_mask & AC_ERR_NCQ ? " <F>" : "");

#ifdef CONFIG_ATA_VERBOSE_ERROR
        if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
                    ATA_ERR)) {
            if (res->command & ATA_BUSY)
                ata_dev_err(qc->dev, "status: { Busy }\n");
            else
                ata_dev_err(qc->dev, "status: { %s%s%s%s}\n",
                  res->command & ATA_DRDY ? "DRDY " : "",
                  res->command & ATA_DF ? "DF " : "",
                  res->command & ATA_DRQ ? "DRQ " : "",
                  res->command & ATA_ERR ? "ERR " : "");
        }

        if (cmd->command != ATA_CMD_PACKET &&
            (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
                     ATA_ABORTED)))
            ata_dev_err(qc->dev, "error: { %s%s%s%s}\n",
              res->feature & ATA_ICRC ? "ICRC " : "",
              res->feature & ATA_UNC ? "UNC " : "",
              res->feature & ATA_IDNF ? "IDNF " : "",
              res->feature & ATA_ABORTED ? "ABRT " : "");
#endif
    }
}

void ata_eh_report(struct ata_port *ap)
{
    struct ata_link *link;

    ata_for_each_link(link, ap, HOST_FIRST)
        ata_eh_link_report(link);
}

static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
            unsigned int *classes, unsigned long deadline,
            bool clear_classes)
{
    struct ata_device *dev;

    if (clear_classes)
        ata_for_each_dev(dev, link, ALL)
            classes[dev->devno] = ATA_DEV_UNKNOWN;

    return reset(link, classes, deadline);
}

static int ata_eh_followup_srst_needed(struct ata_link *link, int rc)
{
    if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
        return 0;
    if (rc == -EAGAIN)
        return 1;
    if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
        return 1;
    return 0;
}

int ata_eh_reset(struct ata_link *link, int classify,
         ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
         ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
{
    struct ata_port *ap = link->ap;
    struct ata_link *slave = ap->slave_link;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_eh_context *sehc = slave ? &slave->eh_context : NULL;
    unsigned int *classes = ehc->classes;
    unsigned int lflags = link->flags;
    int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
    int max_tries = 0, try = 0;
    struct ata_link *failed_link;
    struct ata_device *dev;
    unsigned long deadline, now;
    ata_reset_fn_t reset;
    unsigned long flags;
    u32 sstatus;
    int nr_unknown, rc;

    /*
     * Prepare to reset
     */
    while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
        max_tries++;
    if (link->flags & ATA_LFLAG_RST_ONCE)
        max_tries = 1;
    if (link->flags & ATA_LFLAG_NO_HRST)
        hardreset = NULL;
    if (link->flags & ATA_LFLAG_NO_SRST)
        softreset = NULL;

    /* make sure each reset attempt is at least COOL_DOWN apart */
    if (ehc->i.flags & ATA_EHI_DID_RESET) {
        now = jiffies;
        WARN_ON(time_after(ehc->last_reset, now));
        deadline = ata_deadline(ehc->last_reset,
                    ATA_EH_RESET_COOL_DOWN);
        if (time_before(now, deadline))
            schedule_timeout_uninterruptible(deadline - now);
    }

    spin_lock_irqsave(ap->lock, flags);
    ap->pflags |= ATA_PFLAG_RESETTING;
    spin_unlock_irqrestore(ap->lock, flags);

    ata_eh_about_to_do(link, NULL, ATA_EH_RESET);

    ata_for_each_dev(dev, link, ALL) {
        /* If we issue an SRST then an ATA drive (not ATAPI)
         * may change configuration and be in PIO0 timing. If
         * we do a hard reset (or are coming from power on)
         * this is true for ATA or ATAPI. Until we've set a
         * suitable controller mode we should not touch the
         * bus as we may be talking too fast.
         */
        dev->pio_mode = XFER_PIO_0;

        /* If the controller has a pio mode setup function
         * then use it to set the chipset to rights. Don't
         * touch the DMA setup as that will be dealt with when
         * configuring devices.
         */
        if (ap->ops->set_piomode)
            ap->ops->set_piomode(ap, dev);
    }

    /* prefer hardreset */
    reset = NULL;
    ehc->i.action &= ~ATA_EH_RESET;
    if (hardreset) {
        reset = hardreset;
        ehc->i.action |= ATA_EH_HARDRESET;
    } else if (softreset) {
        reset = softreset;
        ehc->i.action |= ATA_EH_SOFTRESET;
    }

    if (prereset) {
        unsigned long deadline = ata_deadline(jiffies,
                              ATA_EH_PRERESET_TIMEOUT);

        if (slave) {
            sehc->i.action &= ~ATA_EH_RESET;
            sehc->i.action |= ehc->i.action;
        }

        rc = prereset(link, deadline);

        /* If present, do prereset on slave link too.  Reset
         * is skipped iff both master and slave links report
         * -ENOENT or clear ATA_EH_RESET.
         */
        if (slave && (rc == 0 || rc == -ENOENT)) {
            int tmp;

            tmp = prereset(slave, deadline);
            if (tmp != -ENOENT)
                rc = tmp;

            ehc->i.action |= sehc->i.action;
        }

        if (rc) {
            if (rc == -ENOENT) {
                ata_link_dbg(link, "port disabled--ignoring\n");
                ehc->i.action &= ~ATA_EH_RESET;

                ata_for_each_dev(dev, link, ALL)
                    classes[dev->devno] = ATA_DEV_NONE;

                rc = 0;
            } else
                ata_link_err(link,
                         "prereset failed (errno=%d)\n",
                         rc);
            goto out;
        }

        /* prereset() might have cleared ATA_EH_RESET.  If so,
         * bang classes, thaw and return.
         */
        if (reset && !(ehc->i.action & ATA_EH_RESET)) {
            ata_for_each_dev(dev, link, ALL)
                classes[dev->devno] = ATA_DEV_NONE;
            if ((ap->pflags & ATA_PFLAG_FROZEN) &&
                ata_is_host_link(link))
                ata_eh_thaw_port(ap);
            rc = 0;
            goto out;
        }
    }

 retry:
    /*
     * Perform reset
     */
    if (ata_is_host_link(link))
        ata_eh_freeze_port(ap);

    deadline = ata_deadline(jiffies, ata_eh_reset_timeouts[try++]);

    if (reset) {
        if (verbose)
            ata_link_info(link, "%s resetting link\n",
                      reset == softreset ? "soft" : "hard");

        /* mark that this EH session started with reset */
        ehc->last_reset = jiffies;
        if (reset == hardreset)
            ehc->i.flags |= ATA_EHI_DID_HARDRESET;
        else
            ehc->i.flags |= ATA_EHI_DID_SOFTRESET;

        rc = ata_do_reset(link, reset, classes, deadline, true);
        if (rc && rc != -EAGAIN) {
            failed_link = link;
            goto fail;
        }

        /* hardreset slave link if existent */
        if (slave && reset == hardreset) {
            int tmp;

            if (verbose)
                ata_link_info(slave, "hard resetting link\n");

            ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
            tmp = ata_do_reset(slave, reset, classes, deadline,
                       false);
            switch (tmp) {
            case -EAGAIN:
                rc = -EAGAIN;
            case 0:
                break;
            default:
                failed_link = slave;
                rc = tmp;
                goto fail;
            }
        }

        /* perform follow-up SRST if necessary */
        if (reset == hardreset &&
            ata_eh_followup_srst_needed(link, rc)) {
            reset = softreset;

            if (!reset) {
                ata_link_err(link,
         "follow-up softreset required but no softreset available\n");
                failed_link = link;
                rc = -EINVAL;
                goto fail;
            }

            ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
            rc = ata_do_reset(link, reset, classes, deadline, true);
            if (rc) {
                failed_link = link;
                goto fail;
            }
        }
    } else {
        if (verbose)
            ata_link_info(link,
    "no reset method available, skipping reset\n");
        if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
            lflags |= ATA_LFLAG_ASSUME_ATA;
    }

    /*
     * Post-reset processing
     */
    ata_for_each_dev(dev, link, ALL) {
        /* After the reset, the device state is PIO 0 and the
         * controller state is undefined.  Reset also wakes up
         * drives from sleeping mode.
         */
        dev->pio_mode = XFER_PIO_0;
        dev->flags &= ~ATA_DFLAG_SLEEPING;

        if (ata_phys_link_offline(ata_dev_phys_link(dev)))
            continue;

        /* apply class override */
        if (lflags & ATA_LFLAG_ASSUME_ATA)
            classes[dev->devno] = ATA_DEV_ATA;
        else if (lflags & ATA_LFLAG_ASSUME_SEMB)
            classes[dev->devno] = ATA_DEV_SEMB_UNSUP;
    }

    /* record current link speed */
    if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
        link->sata_spd = (sstatus >> 4) & 0xf;
    if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
        slave->sata_spd = (sstatus >> 4) & 0xf;

    /* thaw the port */
    if (ata_is_host_link(link))
        ata_eh_thaw_port(ap);

    /* postreset() should clear hardware SError.  Although SError
     * is cleared during link resume, clearing SError here is
     * necessary as some PHYs raise hotplug events after SRST.
     * This introduces race condition where hotplug occurs between
     * reset and here.  This race is mediated by cross checking
     * link onlineness and classification result later.
     */
    if (postreset) {
        postreset(link, classes);
        if (slave)
            postreset(slave, classes);
    }

    /*
     * Some controllers can't be frozen very well and may set spurious
     * error conditions during reset.  Clear accumulated error
     * information and re-thaw the port if frozen.  As reset is the
     * final recovery action and we cross check link onlineness against
     * device classification later, no hotplug event is lost by this.
     */
    spin_lock_irqsave(link->ap->lock, flags);
    memset(&link->eh_info, 0, sizeof(link->eh_info));
    if (slave)
        memset(&slave->eh_info, 0, sizeof(link->eh_info));
    ap->pflags &= ~ATA_PFLAG_EH_PENDING;
    spin_unlock_irqrestore(link->ap->lock, flags);

    if (ap->pflags & ATA_PFLAG_FROZEN)
        ata_eh_thaw_port(ap);

    /*
     * Make sure onlineness and classification result correspond.
     * Hotplug could have happened during reset and some
     * controllers fail to wait while a drive is spinning up after
     * being hotplugged causing misdetection.  By cross checking
     * link on/offlineness and classification result, those
     * conditions can be reliably detected and retried.
     */
    nr_unknown = 0;
    ata_for_each_dev(dev, link, ALL) {
        if (ata_phys_link_online(ata_dev_phys_link(dev))) {
            if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
                ata_dev_dbg(dev, "link online but device misclassified\n");
                classes[dev->devno] = ATA_DEV_NONE;
                nr_unknown++;
            }
        } else if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
            if (ata_class_enabled(classes[dev->devno]))
                ata_dev_dbg(dev,
                        "link offline, clearing class %d to NONE\n",
                        classes[dev->devno]);
            classes[dev->devno] = ATA_DEV_NONE;
        } else if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
            ata_dev_dbg(dev,
                    "link status unknown, clearing UNKNOWN to NONE\n");
            classes[dev->devno] = ATA_DEV_NONE;
        }
    }

    if (classify && nr_unknown) {
        if (try < max_tries) {
            ata_link_warn(link,
                      "link online but %d devices misclassified, retrying\n",
                      nr_unknown);
            failed_link = link;
            rc = -EAGAIN;
            goto fail;
        }
        ata_link_warn(link,
                  "link online but %d devices misclassified, "
                  "device detection might fail\n", nr_unknown);
    }

    /* reset successful, schedule revalidation */
    ata_eh_done(link, NULL, ATA_EH_RESET);
    if (slave)
        ata_eh_done(slave, NULL, ATA_EH_RESET);
    ehc->last_reset = jiffies;      /* update to completion time */
    ehc->i.action |= ATA_EH_REVALIDATE;
    link->lpm_policy = ATA_LPM_UNKNOWN; /* reset LPM state */

    rc = 0;
 out:
    /* clear hotplug flag */
    ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
    if (slave)
        sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;

    spin_lock_irqsave(ap->lock, flags);
    ap->pflags &= ~ATA_PFLAG_RESETTING;
    spin_unlock_irqrestore(ap->lock, flags);

    return rc;

 fail:
    /* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
    if (!ata_is_host_link(link) &&
        sata_scr_read(link, SCR_STATUS, &sstatus))
        rc = -ERESTART;

    if (try >= max_tries) {
        /*
         * Thaw host port even if reset failed, so that the port
         * can be retried on the next phy event.  This risks
         * repeated EH runs but seems to be a better tradeoff than
         * shutting down a port after a botched hotplug attempt.
         */
        if (ata_is_host_link(link))
            ata_eh_thaw_port(ap);
        goto out;
    }

    now = jiffies;
    if (time_before(now, deadline)) {
        unsigned long delta = deadline - now;

        ata_link_warn(failed_link,
            "reset failed (errno=%d), retrying in %u secs\n",
            rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));

        ata_eh_release(ap);
        while (delta)
            delta = schedule_timeout_uninterruptible(delta);
        ata_eh_acquire(ap);
    }

    /*
     * While disks spinup behind PMP, some controllers fail sending SRST.
     * They need to be reset - as well as the PMP - before retrying.
     */
    if (rc == -ERESTART) {
        if (ata_is_host_link(link))
            ata_eh_thaw_port(ap);
        goto out;
    }

    if (try == max_tries - 1) {
        sata_down_spd_limit(link, 0);
        if (slave)
            sata_down_spd_limit(slave, 0);
    } else if (rc == -EPIPE)
        sata_down_spd_limit(failed_link, 0);

    if (hardreset)
        reset = hardreset;
    goto retry;
}

static inline void ata_eh_pull_park_action(struct ata_port *ap)
{
    struct ata_link *link;
    struct ata_device *dev;
    unsigned long flags;

    /*
     * This function can be thought of as an extended version of
     * ata_eh_about_to_do() specially crafted to accommodate the
     * requirements of ATA_EH_PARK handling. Since the EH thread
     * does not leave the do {} while () loop in ata_eh_recover as
     * long as the timeout for a park request to *one* device on
     * the port has not expired, and since we still want to pick
     * up park requests to other devices on the same port or
     * timeout updates for the same device, we have to pull
     * ATA_EH_PARK actions from eh_info into eh_context.i
     * ourselves at the beginning of each pass over the loop.
     *
     * Additionally, all write accesses to &ap->park_req_pending
     * through INIT_COMPLETION() (see below) or complete_all()
     * (see ata_scsi_park_store()) are protected by the host lock.
     * As a result we have that park_req_pending.done is zero on
     * exit from this function, i.e. when ATA_EH_PARK actions for
     * *all* devices on port ap have been pulled into the
     * respective eh_context structs. If, and only if,
     * park_req_pending.done is non-zero by the time we reach
     * wait_for_completion_timeout(), another ATA_EH_PARK action
     * has been scheduled for at least one of the devices on port
     * ap and we have to cycle over the do {} while () loop in
     * ata_eh_recover() again.
     */

    spin_lock_irqsave(ap->lock, flags);
    INIT_COMPLETION(ap->park_req_pending);
    ata_for_each_link(link, ap, EDGE) {
        ata_for_each_dev(dev, link, ALL) {
            struct ata_eh_info *ehi = &link->eh_info;

            link->eh_context.i.dev_action[dev->devno] |=
                ehi->dev_action[dev->devno] & ATA_EH_PARK;
            ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
        }
    }
    spin_unlock_irqrestore(ap->lock, flags);
}

static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
{
    struct ata_eh_context *ehc = &dev->link->eh_context;
    struct ata_taskfile tf;
    unsigned int err_mask;

    ata_tf_init(dev, &tf);
    if (park) {
        ehc->unloaded_mask |= 1 << dev->devno;
        tf.command = ATA_CMD_IDLEIMMEDIATE;
        tf.feature = 0x44;
        tf.lbal = 0x4c;
        tf.lbam = 0x4e;
        tf.lbah = 0x55;
    } else {
        ehc->unloaded_mask &= ~(1 << dev->devno);
        tf.command = ATA_CMD_CHK_POWER;
    }

    tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
    tf.protocol |= ATA_PROT_NODATA;
    err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
    if (park && (err_mask || tf.lbal != 0xc4)) {
        ata_dev_err(dev, "head unload failed!\n");
        ehc->unloaded_mask &= ~(1 << dev->devno);
    }
}

static int ata_eh_revalidate_and_attach(struct ata_link *link,
                    struct ata_device **r_failed_dev)
{
    struct ata_port *ap = link->ap;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_device *dev;
    unsigned int new_mask = 0;
    unsigned long flags;
    int rc = 0;

    DPRINTK("ENTER\n");

    /* For PATA drive side cable detection to work, IDENTIFY must
     * be done backwards such that PDIAG- is released by the slave
     * device before the master device is identified.
     */
    ata_for_each_dev(dev, link, ALL_REVERSE) {
        unsigned int action = ata_eh_dev_action(dev);
        unsigned int readid_flags = 0;

        if (ehc->i.flags & ATA_EHI_DID_RESET)
            readid_flags |= ATA_READID_POSTRESET;

        if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
            WARN_ON(dev->class == ATA_DEV_PMP);

            if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
                rc = -EIO;
                goto err;
            }

            ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
            rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
                        readid_flags);
            if (rc)
                goto err;

            ata_eh_done(link, dev, ATA_EH_REVALIDATE);

            /* Configuration may have changed, reconfigure
             * transfer mode.
             */
            ehc->i.flags |= ATA_EHI_SETMODE;

            /* schedule the scsi_rescan_device() here */
            schedule_work(&(ap->scsi_rescan_task));
        } else if (dev->class == ATA_DEV_UNKNOWN &&
               ehc->tries[dev->devno] &&
               ata_class_enabled(ehc->classes[dev->devno])) {
            /* Temporarily set dev->class, it will be
             * permanently set once all configurations are
             * complete.  This is necessary because new
             * device configuration is done in two
             * separate loops.
             */
            dev->class = ehc->classes[dev->devno];

            if (dev->class == ATA_DEV_PMP)
                rc = sata_pmp_attach(dev);
            else
                rc = ata_dev_read_id(dev, &dev->class,
                             readid_flags, dev->id);

            /* read_id might have changed class, store and reset */
            ehc->classes[dev->devno] = dev->class;
            dev->class = ATA_DEV_UNKNOWN;

            switch (rc) {
            case 0:
                /* clear error info accumulated during probe */
                ata_ering_clear(&dev->ering);
                new_mask |= 1 << dev->devno;
                break;
            case -ENOENT:
                /* IDENTIFY was issued to non-existent
                 * device.  No need to reset.  Just
                 * thaw and ignore the device.
                 */
                ata_eh_thaw_port(ap);
                break;
            default:
                goto err;
            }
        }
    }

    /* PDIAG- should have been released, ask cable type if post-reset */
    if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
        if (ap->ops->cable_detect)
            ap->cbl = ap->ops->cable_detect(ap);
        ata_force_cbl(ap);
    }

    /* Configure new devices forward such that user doesn't see
     * device detection messages backwards.
     */
    ata_for_each_dev(dev, link, ALL) {
        if (!(new_mask & (1 << dev->devno)))
            continue;

        dev->class = ehc->classes[dev->devno];

        if (dev->class == ATA_DEV_PMP)
            continue;

        ehc->i.flags |= ATA_EHI_PRINTINFO;
        rc = ata_dev_configure(dev);
        ehc->i.flags &= ~ATA_EHI_PRINTINFO;
        if (rc) {
            dev->class = ATA_DEV_UNKNOWN;
            goto err;
        }

        spin_lock_irqsave(ap->lock, flags);
        ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
        spin_unlock_irqrestore(ap->lock, flags);

        /* new device discovered, configure xfermode */
        ehc->i.flags |= ATA_EHI_SETMODE;
    }

    return 0;

 err:
    *r_failed_dev = dev;
    DPRINTK("EXIT rc=%d\n", rc);
    return rc;
}

int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
{
    struct ata_port *ap = link->ap;
    struct ata_device *dev;
    int rc;

    /* if data transfer is verified, clear DUBIOUS_XFER on ering top */
    ata_for_each_dev(dev, link, ENABLED) {
        if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
            struct ata_ering_entry *ent;

            ent = ata_ering_top(&dev->ering);
            if (ent)
                ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
        }
    }

    /* has private set_mode? */
    if (ap->ops->set_mode)
        rc = ap->ops->set_mode(link, r_failed_dev);
    else
        rc = ata_do_set_mode(link, r_failed_dev);

    /* if transfer mode has changed, set DUBIOUS_XFER on device */
    ata_for_each_dev(dev, link, ENABLED) {
        struct ata_eh_context *ehc = &link->eh_context;
        u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
        u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));

        if (dev->xfer_mode != saved_xfer_mode ||
            ata_ncq_enabled(dev) != saved_ncq)
            dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
    }

    return rc;
}

static int atapi_eh_clear_ua(struct ata_device *dev)
{
    int i;

    for (i = 0; i < ATA_EH_UA_TRIES; i++) {
        u8 *sense_buffer = dev->link->ap->sector_buf;
        u8 sense_key = 0;
        unsigned int err_mask;

        err_mask = atapi_eh_tur(dev, &sense_key);
        if (err_mask != 0 && err_mask != AC_ERR_DEV) {
            ata_dev_warn(dev,
                     "TEST_UNIT_READY failed (err_mask=0x%x)\n",
                     err_mask);
            return -EIO;
        }

        if (!err_mask || sense_key != UNIT_ATTENTION)
            return 0;

        err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
        if (err_mask) {
            ata_dev_warn(dev, "failed to clear "
                "UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
            return -EIO;
        }
    }

    ata_dev_warn(dev, "UNIT ATTENTION persists after %d tries\n",
             ATA_EH_UA_TRIES);

    return 0;
}

static int ata_eh_maybe_retry_flush(struct ata_device *dev)
{
    struct ata_link *link = dev->link;
    struct ata_port *ap = link->ap;
    struct ata_queued_cmd *qc;
    struct ata_taskfile tf;
    unsigned int err_mask;
    int rc = 0;

    /* did flush fail for this device? */
    if (!ata_tag_valid(link->active_tag))
        return 0;

    qc = __ata_qc_from_tag(ap, link->active_tag);
    if (qc->dev != dev || (qc->tf.command != ATA_CMD_FLUSH_EXT &&
                   qc->tf.command != ATA_CMD_FLUSH))
        return 0;

    /* if the device failed it, it should be reported to upper layers */
    if (qc->err_mask & AC_ERR_DEV)
        return 0;

    /* flush failed for some other reason, give it another shot */
    ata_tf_init(dev, &tf);

    tf.command = qc->tf.command;
    tf.flags |= ATA_TFLAG_DEVICE;
    tf.protocol = ATA_PROT_NODATA;

    ata_dev_warn(dev, "retrying FLUSH 0x%x Emask 0x%x\n",
               tf.command, qc->err_mask);

    err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
    if (!err_mask) {
        /*
         * FLUSH is complete but there's no way to
         * successfully complete a failed command from EH.
         * Making sure retry is allowed at least once and
         * retrying it should do the trick - whatever was in
         * the cache is already on the platter and this won't
         * cause infinite loop.
         */
        qc->scsicmd->allowed = max(qc->scsicmd->allowed, 1);
    } else {
        ata_dev_warn(dev, "FLUSH failed Emask 0x%x\n",
                   err_mask);
        rc = -EIO;

        /* if device failed it, report it to upper layers */
        if (err_mask & AC_ERR_DEV) {
            qc->err_mask |= AC_ERR_DEV;
            qc->result_tf = tf;
            if (!(ap->pflags & ATA_PFLAG_FROZEN))
                rc = 0;
        }
    }
    return rc;
}

static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
              struct ata_device **r_failed_dev)
{
    struct ata_port *ap = ata_is_host_link(link) ? link->ap : NULL;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL;
    enum ata_lpm_policy old_policy = link->lpm_policy;
    bool no_dipm = link->ap->flags & ATA_FLAG_NO_DIPM;
    unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
    unsigned int err_mask;
    int rc;

    /* if the link or host doesn't do LPM, noop */
    if ((link->flags & ATA_LFLAG_NO_LPM) || (ap && !ap->ops->set_lpm))
        return 0;

    /*
     * DIPM is enabled only for MIN_POWER as some devices
     * misbehave when the host NACKs transition to SLUMBER.  Order
     * device and link configurations such that the host always
     * allows DIPM requests.
     */
    ata_for_each_dev(dev, link, ENABLED) {
        bool hipm = ata_id_has_hipm(dev->id);
        bool dipm = ata_id_has_dipm(dev->id) && !no_dipm;

        /* find the first enabled and LPM enabled devices */
        if (!link_dev)
            link_dev = dev;

        if (!lpm_dev && (hipm || dipm))
            lpm_dev = dev;

        hints &= ~ATA_LPM_EMPTY;
        if (!hipm)
            hints &= ~ATA_LPM_HIPM;

        /* disable DIPM before changing link config */
        if (policy != ATA_LPM_MIN_POWER && dipm) {
            err_mask = ata_dev_set_feature(dev,
                    SETFEATURES_SATA_DISABLE, SATA_DIPM);
            if (err_mask && err_mask != AC_ERR_DEV) {
                ata_dev_warn(dev,
                         "failed to disable DIPM, Emask 0x%x\n",
                         err_mask);
                rc = -EIO;
                goto fail;
            }
        }
    }

    if (ap) {
        rc = ap->ops->set_lpm(link, policy, hints);
        if (!rc && ap->slave_link)
            rc = ap->ops->set_lpm(ap->slave_link, policy, hints);
    } else
        rc = sata_pmp_set_lpm(link, policy, hints);

    /*
     * Attribute link config failure to the first (LPM) enabled
     * device on the link.
     */
    if (rc) {
        if (rc == -EOPNOTSUPP) {
            link->flags |= ATA_LFLAG_NO_LPM;
            return 0;
        }
        dev = lpm_dev ? lpm_dev : link_dev;
        goto fail;
    }

    /*
     * Low level driver acked the transition.  Issue DIPM command
     * with the new policy set.
     */
    link->lpm_policy = policy;
    if (ap && ap->slave_link)
        ap->slave_link->lpm_policy = policy;

    /* host config updated, enable DIPM if transitioning to MIN_POWER */
    ata_for_each_dev(dev, link, ENABLED) {
        if (policy == ATA_LPM_MIN_POWER && !no_dipm &&
            ata_id_has_dipm(dev->id)) {
            err_mask = ata_dev_set_feature(dev,
                    SETFEATURES_SATA_ENABLE, SATA_DIPM);
            if (err_mask && err_mask != AC_ERR_DEV) {
                ata_dev_warn(dev,
                    "failed to enable DIPM, Emask 0x%x\n",
                    err_mask);
                rc = -EIO;
                goto fail;
            }
        }
    }

    return 0;

fail:
    /* restore the old policy */
    link->lpm_policy = old_policy;
    if (ap && ap->slave_link)
        ap->slave_link->lpm_policy = old_policy;

    /* if no device or only one more chance is left, disable LPM */
    if (!dev || ehc->tries[dev->devno] <= 2) {
        ata_link_warn(link, "disabling LPM on the link\n");
        link->flags |= ATA_LFLAG_NO_LPM;
    }
    if (r_failed_dev)
        *r_failed_dev = dev;
    return rc;
}

int ata_link_nr_enabled(struct ata_link *link)
{
    struct ata_device *dev;
    int cnt = 0;

    ata_for_each_dev(dev, link, ENABLED)
        cnt++;
    return cnt;
}

static int ata_link_nr_vacant(struct ata_link *link)
{
    struct ata_device *dev;
    int cnt = 0;

    ata_for_each_dev(dev, link, ALL)
        if (dev->class == ATA_DEV_UNKNOWN)
            cnt++;
    return cnt;
}

static int ata_eh_skip_recovery(struct ata_link *link)
{
    struct ata_port *ap = link->ap;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_device *dev;

    /* skip disabled links */
    if (link->flags & ATA_LFLAG_DISABLED)
        return 1;

    /* skip if explicitly requested */
    if (ehc->i.flags & ATA_EHI_NO_RECOVERY)
        return 1;

    /* thaw frozen port and recover failed devices */
    if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
        return 0;

    /* reset at least once if reset is requested */
    if ((ehc->i.action & ATA_EH_RESET) &&
        !(ehc->i.flags & ATA_EHI_DID_RESET))
        return 0;

    /* skip if class codes for all vacant slots are ATA_DEV_NONE */
    ata_for_each_dev(dev, link, ALL) {
        if (dev->class == ATA_DEV_UNKNOWN &&
            ehc->classes[dev->devno] != ATA_DEV_NONE)
            return 0;
    }

    return 1;
}

static int ata_count_probe_trials_cb(struct ata_ering_entry *ent, void *void_arg)
{
    u64 interval = msecs_to_jiffies(ATA_EH_PROBE_TRIAL_INTERVAL);
    u64 now = get_jiffies_64();
    int *trials = void_arg;

    if ((ent->eflags & ATA_EFLAG_OLD_ER) ||
        (ent->timestamp < now - min(now, interval)))
        return -1;

    (*trials)++;
    return 0;
}

static int ata_eh_schedule_probe(struct ata_device *dev)
{
    struct ata_eh_context *ehc = &dev->link->eh_context;
    struct ata_link *link = ata_dev_phys_link(dev);
    int trials = 0;

    if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
        (ehc->did_probe_mask & (1 << dev->devno)))
        return 0;

    ata_eh_detach_dev(dev);
    ata_dev_init(dev);
    ehc->did_probe_mask |= (1 << dev->devno);
    ehc->i.action |= ATA_EH_RESET;
    ehc->saved_xfer_mode[dev->devno] = 0;
    ehc->saved_ncq_enabled &= ~(1 << dev->devno);

    /* the link maybe in a deep sleep, wake it up */
    if (link->lpm_policy > ATA_LPM_MAX_POWER) {
        if (ata_is_host_link(link))
            link->ap->ops->set_lpm(link, ATA_LPM_MAX_POWER,
                           ATA_LPM_EMPTY);
        else
            sata_pmp_set_lpm(link, ATA_LPM_MAX_POWER,
                     ATA_LPM_EMPTY);
    }

    /* Record and count probe trials on the ering.  The specific
     * error mask used is irrelevant.  Because a successful device
     * detection clears the ering, this count accumulates only if
     * there are consecutive failed probes.
     *
     * If the count is equal to or higher than ATA_EH_PROBE_TRIALS
     * in the last ATA_EH_PROBE_TRIAL_INTERVAL, link speed is
     * forced to 1.5Gbps.
     *
     * This is to work around cases where failed link speed
     * negotiation results in device misdetection leading to
     * infinite DEVXCHG or PHRDY CHG events.
     */
    ata_ering_record(&dev->ering, 0, AC_ERR_OTHER);
    ata_ering_map(&dev->ering, ata_count_probe_trials_cb, &trials);

    if (trials > ATA_EH_PROBE_TRIALS)
        sata_down_spd_limit(link, 1);

    return 1;
}

static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
{
    struct ata_eh_context *ehc = &dev->link->eh_context;

    /* -EAGAIN from EH routine indicates retry without prejudice.
     * The requester is responsible for ensuring forward progress.
     */
    if (err != -EAGAIN)
        ehc->tries[dev->devno]--;

    switch (err) {
    case -ENODEV:
        /* device missing or wrong IDENTIFY data, schedule probing */
        ehc->i.probe_mask |= (1 << dev->devno);
    case -EINVAL:
        /* give it just one more chance */
        ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
    case -EIO:
        if (ehc->tries[dev->devno] == 1) {
            /* This is the last chance, better to slow
             * down than lose it.
             */
            sata_down_spd_limit(ata_dev_phys_link(dev), 0);
            if (dev->pio_mode > XFER_PIO_0)
                ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
        }
    }

    if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
        /* disable device if it has used up all its chances */
        ata_dev_disable(dev);

        /* detach if offline */
        if (ata_phys_link_offline(ata_dev_phys_link(dev)))
            ata_eh_detach_dev(dev);

        /* schedule probe if necessary */
        if (ata_eh_schedule_probe(dev)) {
            ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
            memset(ehc->cmd_timeout_idx[dev->devno], 0,
                   sizeof(ehc->cmd_timeout_idx[dev->devno]));
        }

        return 1;
    } else {
        ehc->i.action |= ATA_EH_RESET;
        return 0;
    }
}

int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
           ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
           ata_postreset_fn_t postreset,
           struct ata_link **r_failed_link)
{
    struct ata_link *link;
    struct ata_device *dev;
    int rc, nr_fails;
    unsigned long flags, deadline;

    DPRINTK("ENTER\n");

    /* prep for recovery */
    ata_for_each_link(link, ap, EDGE) {
        struct ata_eh_context *ehc = &link->eh_context;

        /* re-enable link? */
        if (ehc->i.action & ATA_EH_ENABLE_LINK) {
            ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
            spin_lock_irqsave(ap->lock, flags);
            link->flags &= ~ATA_LFLAG_DISABLED;
            spin_unlock_irqrestore(ap->lock, flags);
            ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
        }

        ata_for_each_dev(dev, link, ALL) {
            if (link->flags & ATA_LFLAG_NO_RETRY)
                ehc->tries[dev->devno] = 1;
            else
                ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;

            /* collect port action mask recorded in dev actions */
            ehc->i.action |= ehc->i.dev_action[dev->devno] &
                     ~ATA_EH_PERDEV_MASK;
            ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;

            /* process hotplug request */
            if (dev->flags & ATA_DFLAG_DETACH)
                ata_eh_detach_dev(dev);

            /* schedule probe if necessary */
            if (!ata_dev_enabled(dev))
                ata_eh_schedule_probe(dev);
        }
    }

 retry:
    rc = 0;

    /* if UNLOADING, finish immediately */
    if (ap->pflags & ATA_PFLAG_UNLOADING)
        goto out;

    /* prep for EH */
    ata_for_each_link(link, ap, EDGE) {
        struct ata_eh_context *ehc = &link->eh_context;

        /* skip EH if possible. */
        if (ata_eh_skip_recovery(link))
            ehc->i.action = 0;

        ata_for_each_dev(dev, link, ALL)
            ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
    }

    /* reset */
    ata_for_each_link(link, ap, EDGE) {
        struct ata_eh_context *ehc = &link->eh_context;

        if (!(ehc->i.action & ATA_EH_RESET))
            continue;

        rc = ata_eh_reset(link, ata_link_nr_vacant(link),
                  prereset, softreset, hardreset, postreset);
        if (rc) {
            ata_link_err(link, "reset failed, giving up\n");
            goto out;
        }
    }

    do {
        unsigned long now;

        /*
         * clears ATA_EH_PARK in eh_info and resets
         * ap->park_req_pending
         */
        ata_eh_pull_park_action(ap);

        deadline = jiffies;
        ata_for_each_link(link, ap, EDGE) {
            ata_for_each_dev(dev, link, ALL) {
                struct ata_eh_context *ehc = &link->eh_context;
                unsigned long tmp;

                if (dev->class != ATA_DEV_ATA)
                    continue;
                if (!(ehc->i.dev_action[dev->devno] &
                      ATA_EH_PARK))
                    continue;
                tmp = dev->unpark_deadline;
                if (time_before(deadline, tmp))
                    deadline = tmp;
                else if (time_before_eq(tmp, jiffies))
                    continue;
                if (ehc->unloaded_mask & (1 << dev->devno))
                    continue;

                ata_eh_park_issue_cmd(dev, 1);
            }
        }

        now = jiffies;
        if (time_before_eq(deadline, now))
            break;

        ata_eh_release(ap);
        deadline = wait_for_completion_timeout(&ap->park_req_pending,
                               deadline - now);
        ata_eh_acquire(ap);
    } while (deadline);
    ata_for_each_link(link, ap, EDGE) {
        ata_for_each_dev(dev, link, ALL) {
            if (!(link->eh_context.unloaded_mask &
                  (1 << dev->devno)))
                continue;

            ata_eh_park_issue_cmd(dev, 0);
            ata_eh_done(link, dev, ATA_EH_PARK);
        }
    }

    /* the rest */
    nr_fails = 0;
    ata_for_each_link(link, ap, PMP_FIRST) {
        struct ata_eh_context *ehc = &link->eh_context;

        if (sata_pmp_attached(ap) && ata_is_host_link(link))
            goto config_lpm;

        /* revalidate existing devices and attach new ones */
        rc = ata_eh_revalidate_and_attach(link, &dev);
        if (rc)
            goto rest_fail;

        /* if PMP got attached, return, pmp EH will take care of it */
        if (link->device->class == ATA_DEV_PMP) {
            ehc->i.action = 0;
            return 0;
        }

        /* configure transfer mode if necessary */
        if (ehc->i.flags & ATA_EHI_SETMODE) {
            rc = ata_set_mode(link, &dev);
            if (rc)
                goto rest_fail;
            ehc->i.flags &= ~ATA_EHI_SETMODE;
        }

        /* If reset has been issued, clear UA to avoid
         * disrupting the current users of the device.
         */
        if (ehc->i.flags & ATA_EHI_DID_RESET) {
            ata_for_each_dev(dev, link, ALL) {
                if (dev->class != ATA_DEV_ATAPI)
                    continue;
                rc = atapi_eh_clear_ua(dev);
                if (rc)
                    goto rest_fail;
            }
        }

        /* retry flush if necessary */
        ata_for_each_dev(dev, link, ALL) {
            if (dev->class != ATA_DEV_ATA)
                continue;
            rc = ata_eh_maybe_retry_flush(dev);
            if (rc)
                goto rest_fail;
        }

    config_lpm:
        /* configure link power saving */
        if (link->lpm_policy != ap->target_lpm_policy) {
            rc = ata_eh_set_lpm(link, ap->target_lpm_policy, &dev);
            if (rc)
                goto rest_fail;
        }

        /* this link is okay now */
        ehc->i.flags = 0;
        continue;

    rest_fail:
        nr_fails++;
        if (dev)
            ata_eh_handle_dev_fail(dev, rc);

        if (ap->pflags & ATA_PFLAG_FROZEN) {
            /* PMP reset requires working host port.
             * Can't retry if it's frozen.
             */
            if (sata_pmp_attached(ap))
                goto out;
            break;
        }
    }

    if (nr_fails)
        goto retry;

 out:
    if (rc && r_failed_link)
        *r_failed_link = link;

    DPRINTK("EXIT, rc=%d\n", rc);
    return rc;
}

void ata_eh_finish(struct ata_port *ap)
{
    int tag;

    /* retry or finish qcs */
    for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
        struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);

        if (!(qc->flags & ATA_QCFLAG_FAILED))
            continue;

        if (qc->err_mask) {
            /* FIXME: Once EH migration is complete,
             * generate sense data in this function,
             * considering both err_mask and tf.
             */
            if (qc->flags & ATA_QCFLAG_RETRY)
                ata_eh_qc_retry(qc);
            else
                ata_eh_qc_complete(qc);
        } else {
            if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
                ata_eh_qc_complete(qc);
            } else {
                /* feed zero TF to sense generation */
                memset(&qc->result_tf, 0, sizeof(qc->result_tf));
                ata_eh_qc_retry(qc);
            }
        }
    }

    /* make sure nr_active_links is zero after EH */
    WARN_ON(ap->nr_active_links);
    ap->nr_active_links = 0;
}

void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
           ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
           ata_postreset_fn_t postreset)
{
    struct ata_device *dev;
    int rc;

    ata_eh_autopsy(ap);
    ata_eh_report(ap);

    rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
                NULL);
    if (rc) {
        ata_for_each_dev(dev, &ap->link, ALL)
            ata_dev_disable(dev);
    }

    ata_eh_finish(ap);
}

void ata_std_error_handler(struct ata_port *ap)
{
    struct ata_port_operations *ops = ap->ops;
    ata_reset_fn_t hardreset = ops->hardreset;

    /* ignore built-in hardreset if SCR access is not available */
    if (hardreset == sata_std_hardreset && !sata_scr_valid(&ap->link))
        hardreset = NULL;

    ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
}

#ifdef CONFIG_PM

static void ata_eh_handle_port_suspend(struct ata_port *ap)
{
    unsigned long flags;
    int rc = 0;

    /* are we suspending? */
    spin_lock_irqsave(ap->lock, flags);
    if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
        ap->pm_mesg.event == PM_EVENT_ON) {
        spin_unlock_irqrestore(ap->lock, flags);
        return;
    }
    spin_unlock_irqrestore(ap->lock, flags);

    WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);

    /* tell ACPI we're suspending */
    rc = ata_acpi_on_suspend(ap);
    if (rc)
        goto out;

    /* suspend */
    ata_eh_freeze_port(ap);

    if (ap->ops->port_suspend)
        rc = ap->ops->port_suspend(ap, ap->pm_mesg);

    ata_acpi_set_state(ap, PMSG_SUSPEND);
 out:
    /* report result */
    spin_lock_irqsave(ap->lock, flags);

    ap->pflags &= ~ATA_PFLAG_PM_PENDING;
    if (rc == 0)
        ap->pflags |= ATA_PFLAG_SUSPENDED;
    else if (ap->pflags & ATA_PFLAG_FROZEN)
        ata_port_schedule_eh(ap);

    if (ap->pm_result) {
        *ap->pm_result = rc;
        ap->pm_result = NULL;
    }

    spin_unlock_irqrestore(ap->lock, flags);

    return;
}

static void ata_eh_handle_port_resume(struct ata_port *ap)
{
    struct ata_link *link;
    struct ata_device *dev;
    unsigned long flags;
    int rc = 0;

    /* are we resuming? */
    spin_lock_irqsave(ap->lock, flags);
    if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
        ap->pm_mesg.event != PM_EVENT_ON) {
        spin_unlock_irqrestore(ap->lock, flags);
        return;
    }
    spin_unlock_irqrestore(ap->lock, flags);

    WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));

    /*
     * Error timestamps are in jiffies which doesn't run while
     * suspended and PHY events during resume isn't too uncommon.
     * When the two are combined, it can lead to unnecessary speed
     * downs if the machine is suspended and resumed repeatedly.
     * Clear error history.
     */
    ata_for_each_link(link, ap, HOST_FIRST)
        ata_for_each_dev(dev, link, ALL)
            ata_ering_clear(&dev->ering);

    ata_acpi_set_state(ap, PMSG_ON);

    if (ap->ops->port_resume)
        rc = ap->ops->port_resume(ap);

    /* tell ACPI that we're resuming */
    ata_acpi_on_resume(ap);

    /* report result */
    spin_lock_irqsave(ap->lock, flags);
    ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
    if (ap->pm_result) {
        *ap->pm_result = rc;
        ap->pm_result = NULL;
    }
    spin_unlock_irqrestore(ap->lock, flags);
}
#endif /* CONFIG_PM */