libata-pmp.c

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/*
 * libata-pmp.c - libata port multiplier support
 *
 * Copyright (c) 2007  SUSE Linux Products GmbH
 * Copyright (c) 2007  Tejun Heo <[email protected]>
 *
 * This file is released under the GPLv2.
 */

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/libata.h>
#include <linux/slab.h>
#include "libata.h"
#include "libata-transport.h"

const struct ata_port_operations sata_pmp_port_ops = {
    .inherits       = &sata_port_ops,
    .pmp_prereset       = ata_std_prereset,
    .pmp_hardreset      = sata_std_hardreset,
    .pmp_postreset      = ata_std_postreset,
    .error_handler      = sata_pmp_error_handler,
};

static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
{
    struct ata_port *ap = link->ap;
    struct ata_device *pmp_dev = ap->link.device;
    struct ata_taskfile tf;
    unsigned int err_mask;

    ata_tf_init(pmp_dev, &tf);
    tf.command = ATA_CMD_PMP_READ;
    tf.protocol = ATA_PROT_NODATA;
    tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
    tf.feature = reg;
    tf.device = link->pmp;

    err_mask = ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
                     SATA_PMP_RW_TIMEOUT);
    if (err_mask)
        return err_mask;

    *r_val = tf.nsect | tf.lbal << 8 | tf.lbam << 16 | tf.lbah << 24;
    return 0;
}

static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val)
{
    struct ata_port *ap = link->ap;
    struct ata_device *pmp_dev = ap->link.device;
    struct ata_taskfile tf;

    ata_tf_init(pmp_dev, &tf);
    tf.command = ATA_CMD_PMP_WRITE;
    tf.protocol = ATA_PROT_NODATA;
    tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
    tf.feature = reg;
    tf.device = link->pmp;
    tf.nsect = val & 0xff;
    tf.lbal = (val >> 8) & 0xff;
    tf.lbam = (val >> 16) & 0xff;
    tf.lbah = (val >> 24) & 0xff;

    return ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
                 SATA_PMP_RW_TIMEOUT);
}

int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
{
    struct ata_link *link = qc->dev->link;
    struct ata_port *ap = link->ap;

    if (ap->excl_link == NULL || ap->excl_link == link) {
        if (ap->nr_active_links == 0 || ata_link_active(link)) {
            qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
            return ata_std_qc_defer(qc);
        }

        ap->excl_link = link;
    }

    return ATA_DEFER_PORT;
}

int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
{
    unsigned int err_mask;

    if (reg > SATA_PMP_PSCR_CONTROL)
        return -EINVAL;

    err_mask = sata_pmp_read(link, reg, r_val);
    if (err_mask) {
        ata_link_warn(link, "failed to read SCR %d (Emask=0x%x)\n",
                  reg, err_mask);
        return -EIO;
    }
    return 0;
}

int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
{
    unsigned int err_mask;

    if (reg > SATA_PMP_PSCR_CONTROL)
        return -EINVAL;

    err_mask = sata_pmp_write(link, reg, val);
    if (err_mask) {
        ata_link_warn(link, "failed to write SCR %d (Emask=0x%x)\n",
                  reg, err_mask);
        return -EIO;
    }
    return 0;
}

int sata_pmp_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
             unsigned hints)
{
    return sata_link_scr_lpm(link, policy, true);
}

static int sata_pmp_read_gscr(struct ata_device *dev, u32 *gscr)
{
    static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
    int i;

    for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
        int reg = gscr_to_read[i];
        unsigned int err_mask;

        err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
        if (err_mask) {
            ata_dev_err(dev, "failed to read PMP GSCR[%d] (Emask=0x%x)\n",
                    reg, err_mask);
            return -EIO;
        }
    }

    return 0;
}

static const char *sata_pmp_spec_rev_str(const u32 *gscr)
{
    u32 rev = gscr[SATA_PMP_GSCR_REV];

    if (rev & (1 << 3))
        return "1.2";
    if (rev & (1 << 2))
        return "1.1";
    if (rev & (1 << 1))
        return "1.0";
    return "<unknown>";
}

#define PMP_GSCR_SII_POL 129

static int sata_pmp_configure(struct ata_device *dev, int print_info)
{
    struct ata_port *ap = dev->link->ap;
    u32 *gscr = dev->gscr;
    u16 vendor = sata_pmp_gscr_vendor(gscr);
    u16 devid = sata_pmp_gscr_devid(gscr);
    unsigned int err_mask = 0;
    const char *reason;
    int nr_ports, rc;

    nr_ports = sata_pmp_gscr_ports(gscr);

    if (nr_ports <= 0 || nr_ports > SATA_PMP_MAX_PORTS) {
        rc = -EINVAL;
        reason = "invalid nr_ports";
        goto fail;
    }

    if ((ap->flags & ATA_FLAG_AN) &&
        (gscr[SATA_PMP_GSCR_FEAT] & SATA_PMP_FEAT_NOTIFY))
        dev->flags |= ATA_DFLAG_AN;

    /* monitor SERR_PHYRDY_CHG on fan-out ports */
    err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
                  SERR_PHYRDY_CHG);
    if (err_mask) {
        rc = -EIO;
        reason = "failed to write GSCR_ERROR_EN";
        goto fail;
    }

    /* Disable sending Early R_OK.
     * With "cached read" HDD testing and multiple ports busy on a SATA
     * host controller, 3726 PMP will very rarely drop a deferred
     * R_OK that was intended for the host. Symptom will be all
     * 5 drives under test will timeout, get reset, and recover.
     */
    if (vendor == 0x1095 && devid == 0x3726) {
        u32 reg;

        err_mask = sata_pmp_read(&ap->link, PMP_GSCR_SII_POL, &reg);
        if (err_mask) {
            rc = -EIO;
            reason = "failed to read Sil3726 Private Register";
            goto fail;
        }
        reg &= ~0x1;
        err_mask = sata_pmp_write(&ap->link, PMP_GSCR_SII_POL, reg);
        if (err_mask) {
            rc = -EIO;
            reason = "failed to write Sil3726 Private Register";
            goto fail;
        }
    }

    if (print_info) {
        ata_dev_info(dev, "Port Multiplier %s, "
                 "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
                 sata_pmp_spec_rev_str(gscr), vendor, devid,
                 sata_pmp_gscr_rev(gscr),
                 nr_ports, gscr[SATA_PMP_GSCR_FEAT_EN],
                 gscr[SATA_PMP_GSCR_FEAT]);

        if (!(dev->flags & ATA_DFLAG_AN))
            ata_dev_info(dev,
                "Asynchronous notification not supported, "
                "hotplug won't work on fan-out ports. Use warm-plug instead.\n");
    }

    return 0;

 fail:
    ata_dev_err(dev,
            "failed to configure Port Multiplier (%s, Emask=0x%x)\n",
            reason, err_mask);
    return rc;
}

static int sata_pmp_init_links (struct ata_port *ap, int nr_ports)
{
    struct ata_link *pmp_link = ap->pmp_link;
    int i, err;

    if (!pmp_link) {
        pmp_link = kzalloc(sizeof(pmp_link[0]) * SATA_PMP_MAX_PORTS,
                   GFP_NOIO);
        if (!pmp_link)
            return -ENOMEM;

        for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
            ata_link_init(ap, &pmp_link[i], i);

        ap->pmp_link = pmp_link;

        for (i = 0; i < SATA_PMP_MAX_PORTS; i++) {
            err = ata_tlink_add(&pmp_link[i]);
            if (err) {
                goto err_tlink;
            }
        }
    }

    for (i = 0; i < nr_ports; i++) {
        struct ata_link *link = &pmp_link[i];
        struct ata_eh_context *ehc = &link->eh_context;

        link->flags = 0;
        ehc->i.probe_mask |= ATA_ALL_DEVICES;
        ehc->i.action |= ATA_EH_RESET;
    }

    return 0;
  err_tlink:
    while (--i >= 0)
        ata_tlink_delete(&pmp_link[i]);
    kfree(pmp_link);
    ap->pmp_link = NULL;
    return err;
}

static void sata_pmp_quirks(struct ata_port *ap)
{
    u32 *gscr = ap->link.device->gscr;
    u16 vendor = sata_pmp_gscr_vendor(gscr);
    u16 devid = sata_pmp_gscr_devid(gscr);
    struct ata_link *link;

    if (vendor == 0x1095 && devid == 0x3726) {
        /* sil3726 quirks */
        ata_for_each_link(link, ap, EDGE) {
            /* link reports offline after LPM */
            link->flags |= ATA_LFLAG_NO_LPM;

            /* Class code report is unreliable. */
            if (link->pmp < 5)
                link->flags |= ATA_LFLAG_ASSUME_ATA;

            /* port 5 is for SEMB device and it doesn't like SRST */
            if (link->pmp == 5)
                link->flags |= ATA_LFLAG_NO_SRST |
                           ATA_LFLAG_ASSUME_SEMB;
        }
    } else if (vendor == 0x1095 && devid == 0x4723) {
        /* sil4723 quirks */
        ata_for_each_link(link, ap, EDGE) {
            /* link reports offline after LPM */
            link->flags |= ATA_LFLAG_NO_LPM;

            /* class code report is unreliable */
            if (link->pmp < 2)
                link->flags |= ATA_LFLAG_ASSUME_ATA;

            /* the config device at port 2 locks up on SRST */
            if (link->pmp == 2)
                link->flags |= ATA_LFLAG_NO_SRST |
                           ATA_LFLAG_ASSUME_ATA;
        }
    } else if (vendor == 0x1095 && devid == 0x4726) {
        /* sil4726 quirks */
        ata_for_each_link(link, ap, EDGE) {
            /* link reports offline after LPM */
            link->flags |= ATA_LFLAG_NO_LPM;

            /* Class code report is unreliable and SRST
             * times out under certain configurations.
             * Config device can be at port 0 or 5 and
             * locks up on SRST.
             */
            if (link->pmp <= 5)
                link->flags |= ATA_LFLAG_NO_SRST |
                           ATA_LFLAG_ASSUME_ATA;

            /* Port 6 is for SEMB device which doesn't
             * like SRST either.
             */
            if (link->pmp == 6)
                link->flags |= ATA_LFLAG_NO_SRST |
                           ATA_LFLAG_ASSUME_SEMB;
        }
    } else if (vendor == 0x1095 && (devid == 0x5723 || devid == 0x5733 ||
                    devid == 0x5734 || devid == 0x5744)) {
        /* sil5723/5744 quirks */

        /* sil5723/5744 has either two or three downstream
         * ports depending on operation mode.  The last port
         * is empty if any actual IO device is available or
         * occupied by a pseudo configuration device
         * otherwise.  Don't try hard to recover it.
         */
        ap->pmp_link[ap->nr_pmp_links - 1].flags |= ATA_LFLAG_NO_RETRY;
    } else if (vendor == 0x197b && devid == 0x2352) {
        /* chip found in Thermaltake BlackX Duet, jmicron JMB350? */
        ata_for_each_link(link, ap, EDGE) {
            /* SRST breaks detection and disks get misclassified
             * LPM disabled to avoid potential problems
             */
            link->flags |= ATA_LFLAG_NO_LPM |
                       ATA_LFLAG_NO_SRST |
                       ATA_LFLAG_ASSUME_ATA;
        }
    }
}

int sata_pmp_attach(struct ata_device *dev)
{
    struct ata_link *link = dev->link;
    struct ata_port *ap = link->ap;
    unsigned long flags;
    struct ata_link *tlink;
    int rc;

    /* is it hanging off the right place? */
    if (!sata_pmp_supported(ap)) {
        ata_dev_err(dev, "host does not support Port Multiplier\n");
        return -EINVAL;
    }

    if (!ata_is_host_link(link)) {
        ata_dev_err(dev, "Port Multipliers cannot be nested\n");
        return -EINVAL;
    }

    if (dev->devno) {
        ata_dev_err(dev, "Port Multiplier must be the first device\n");
        return -EINVAL;
    }

    WARN_ON(link->pmp != 0);
    link->pmp = SATA_PMP_CTRL_PORT;

    /* read GSCR block */
    rc = sata_pmp_read_gscr(dev, dev->gscr);
    if (rc)
        goto fail;

    /* config PMP */
    rc = sata_pmp_configure(dev, 1);
    if (rc)
        goto fail;

    rc = sata_pmp_init_links(ap, sata_pmp_gscr_ports(dev->gscr));
    if (rc) {
        ata_dev_info(dev, "failed to initialize PMP links\n");
        goto fail;
    }

    /* attach it */
    spin_lock_irqsave(ap->lock, flags);
    WARN_ON(ap->nr_pmp_links);
    ap->nr_pmp_links = sata_pmp_gscr_ports(dev->gscr);
    spin_unlock_irqrestore(ap->lock, flags);

    sata_pmp_quirks(ap);

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

    ata_for_each_link(tlink, ap, EDGE)
        sata_link_init_spd(tlink);

    return 0;

 fail:
    link->pmp = 0;
    return rc;
}

static void sata_pmp_detach(struct ata_device *dev)
{
    struct ata_link *link = dev->link;
    struct ata_port *ap = link->ap;
    struct ata_link *tlink;
    unsigned long flags;

    ata_dev_info(dev, "Port Multiplier detaching\n");

    WARN_ON(!ata_is_host_link(link) || dev->devno ||
        link->pmp != SATA_PMP_CTRL_PORT);

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

    ata_for_each_link(tlink, ap, EDGE)
        ata_eh_detach_dev(tlink->device);

    spin_lock_irqsave(ap->lock, flags);
    ap->nr_pmp_links = 0;
    link->pmp = 0;
    spin_unlock_irqrestore(ap->lock, flags);
}

static int sata_pmp_same_pmp(struct ata_device *dev, const u32 *new_gscr)
{
    const u32 *old_gscr = dev->gscr;
    u16 old_vendor, new_vendor, old_devid, new_devid;
    int old_nr_ports, new_nr_ports;

    old_vendor = sata_pmp_gscr_vendor(old_gscr);
    new_vendor = sata_pmp_gscr_vendor(new_gscr);
    old_devid = sata_pmp_gscr_devid(old_gscr);
    new_devid = sata_pmp_gscr_devid(new_gscr);
    old_nr_ports = sata_pmp_gscr_ports(old_gscr);
    new_nr_ports = sata_pmp_gscr_ports(new_gscr);

    if (old_vendor != new_vendor) {
        ata_dev_info(dev,
                 "Port Multiplier vendor mismatch '0x%x' != '0x%x'\n",
                 old_vendor, new_vendor);
        return 0;
    }

    if (old_devid != new_devid) {
        ata_dev_info(dev,
                 "Port Multiplier device ID mismatch '0x%x' != '0x%x'\n",
                 old_devid, new_devid);
        return 0;
    }

    if (old_nr_ports != new_nr_ports) {
        ata_dev_info(dev,
                 "Port Multiplier nr_ports mismatch '0x%x' != '0x%x'\n",
                 old_nr_ports, new_nr_ports);
        return 0;
    }

    return 1;
}

static int sata_pmp_revalidate(struct ata_device *dev, unsigned int new_class)
{
    struct ata_link *link = dev->link;
    struct ata_port *ap = link->ap;
    u32 *gscr = (void *)ap->sector_buf;
    int rc;

    DPRINTK("ENTER\n");

    ata_eh_about_to_do(link, NULL, ATA_EH_REVALIDATE);

    if (!ata_dev_enabled(dev)) {
        rc = -ENODEV;
        goto fail;
    }

    /* wrong class? */
    if (ata_class_enabled(new_class) && new_class != ATA_DEV_PMP) {
        rc = -ENODEV;
        goto fail;
    }

    /* read GSCR */
    rc = sata_pmp_read_gscr(dev, gscr);
    if (rc)
        goto fail;

    /* is the pmp still there? */
    if (!sata_pmp_same_pmp(dev, gscr)) {
        rc = -ENODEV;
        goto fail;
    }

    memcpy(dev->gscr, gscr, sizeof(gscr[0]) * SATA_PMP_GSCR_DWORDS);

    rc = sata_pmp_configure(dev, 0);
    if (rc)
        goto fail;

    ata_eh_done(link, NULL, ATA_EH_REVALIDATE);

    DPRINTK("EXIT, rc=0\n");
    return 0;

 fail:
    ata_dev_err(dev, "PMP revalidation failed (errno=%d)\n", rc);
    DPRINTK("EXIT, rc=%d\n", rc);
    return rc;
}

static int sata_pmp_revalidate_quick(struct ata_device *dev)
{
    unsigned int err_mask;
    u32 prod_id;

    err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
    if (err_mask) {
        ata_dev_err(dev,
                "failed to read PMP product ID (Emask=0x%x)\n",
                err_mask);
        return -EIO;
    }

    if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
        ata_dev_err(dev, "PMP product ID mismatch\n");
        /* something weird is going on, request full PMP recovery */
        return -EIO;
    }

    return 0;
}

static int sata_pmp_eh_recover_pmp(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 *link = &ap->link;
    struct ata_eh_context *ehc = &link->eh_context;
    struct ata_device *dev = link->device;
    int tries = ATA_EH_PMP_TRIES;
    int detach = 0, rc = 0;
    int reval_failed = 0;

    DPRINTK("ENTER\n");

    if (dev->flags & ATA_DFLAG_DETACH) {
        detach = 1;
        goto fail;
    }

 retry:
    ehc->classes[0] = ATA_DEV_UNKNOWN;

    if (ehc->i.action & ATA_EH_RESET) {
        struct ata_link *tlink;

        /* reset */
        rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
                  postreset);
        if (rc) {
            ata_link_err(link, "failed to reset PMP, giving up\n");
            goto fail;
        }

        /* PMP is reset, SErrors cannot be trusted, scan all */
        ata_for_each_link(tlink, ap, EDGE) {
            struct ata_eh_context *ehc = &tlink->eh_context;

            ehc->i.probe_mask |= ATA_ALL_DEVICES;
            ehc->i.action |= ATA_EH_RESET;
        }
    }

    /* If revalidation is requested, revalidate and reconfigure;
     * otherwise, do quick revalidation.
     */
    if (ehc->i.action & ATA_EH_REVALIDATE)
        rc = sata_pmp_revalidate(dev, ehc->classes[0]);
    else
        rc = sata_pmp_revalidate_quick(dev);

    if (rc) {
        tries--;

        if (rc == -ENODEV) {
            ehc->i.probe_mask |= ATA_ALL_DEVICES;
            detach = 1;
            /* give it just two more chances */
            tries = min(tries, 2);
        }

        if (tries) {
            /* consecutive revalidation failures? speed down */
            if (reval_failed)
                sata_down_spd_limit(link, 0);
            else
                reval_failed = 1;

            ehc->i.action |= ATA_EH_RESET;
            goto retry;
        } else {
            ata_dev_err(dev,
                    "failed to recover PMP after %d tries, giving up\n",
                    ATA_EH_PMP_TRIES);
            goto fail;
        }
    }

    /* okay, PMP resurrected */
    ehc->i.flags = 0;

    DPRINTK("EXIT, rc=0\n");
    return 0;

 fail:
    sata_pmp_detach(dev);
    if (detach)
        ata_eh_detach_dev(dev);
    else
        ata_dev_disable(dev);

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

static int sata_pmp_eh_handle_disabled_links(struct ata_port *ap)
{
    struct ata_link *link;
    unsigned long flags;
    int rc;

    spin_lock_irqsave(ap->lock, flags);

    ata_for_each_link(link, ap, EDGE) {
        if (!(link->flags & ATA_LFLAG_DISABLED))
            continue;

        spin_unlock_irqrestore(ap->lock, flags);

        /* Some PMPs require hardreset sequence to get
         * SError.N working.
         */
        sata_link_hardreset(link, sata_deb_timing_normal,
                ata_deadline(jiffies, ATA_TMOUT_INTERNAL_QUICK),
                NULL, NULL);

        /* unconditionally clear SError.N */
        rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
        if (rc) {
            ata_link_err(link,
                     "failed to clear SError.N (errno=%d)\n",
                     rc);
            return rc;
        }

        spin_lock_irqsave(ap->lock, flags);
    }

    spin_unlock_irqrestore(ap->lock, flags);

    return 0;
}

static int sata_pmp_handle_link_fail(struct ata_link *link, int *link_tries)
{
    struct ata_port *ap = link->ap;
    unsigned long flags;

    if (link_tries[link->pmp] && --link_tries[link->pmp])
        return 1;

    /* disable this link */
    if (!(link->flags & ATA_LFLAG_DISABLED)) {
        ata_link_warn(link,
            "failed to recover link after %d tries, disabling\n",
            ATA_EH_PMP_LINK_TRIES);

        spin_lock_irqsave(ap->lock, flags);
        link->flags |= ATA_LFLAG_DISABLED;
        spin_unlock_irqrestore(ap->lock, flags);
    }

    ata_dev_disable(link->device);
    link->eh_context.i.action = 0;

    return 0;
}

static int sata_pmp_eh_recover(struct ata_port *ap)
{
    struct ata_port_operations *ops = ap->ops;
    int pmp_tries, link_tries[SATA_PMP_MAX_PORTS];
    struct ata_link *pmp_link = &ap->link;
    struct ata_device *pmp_dev = pmp_link->device;
    struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;
    u32 *gscr = pmp_dev->gscr;
    struct ata_link *link;
    struct ata_device *dev;
    unsigned int err_mask;
    u32 gscr_error, sntf;
    int cnt, rc;

    pmp_tries = ATA_EH_PMP_TRIES;
    ata_for_each_link(link, ap, EDGE)
        link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;

 retry:
    /* PMP attached? */
    if (!sata_pmp_attached(ap)) {
        rc = ata_eh_recover(ap, ops->prereset, ops->softreset,
                    ops->hardreset, ops->postreset, NULL);
        if (rc) {
            ata_for_each_dev(dev, &ap->link, ALL)
                ata_dev_disable(dev);
            return rc;
        }

        if (pmp_dev->class != ATA_DEV_PMP)
            return 0;

        /* new PMP online */
        ata_for_each_link(link, ap, EDGE)
            link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;

        /* fall through */
    }

    /* recover pmp */
    rc = sata_pmp_eh_recover_pmp(ap, ops->prereset, ops->softreset,
                     ops->hardreset, ops->postreset);
    if (rc)
        goto pmp_fail;

    /* PHY event notification can disturb reset and other recovery
     * operations.  Turn it off.
     */
    if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
        gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;

        err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
                      gscr[SATA_PMP_GSCR_FEAT_EN]);
        if (err_mask) {
            ata_link_warn(pmp_link,
                "failed to disable NOTIFY (err_mask=0x%x)\n",
                err_mask);
            goto pmp_fail;
        }
    }

    /* handle disabled links */
    rc = sata_pmp_eh_handle_disabled_links(ap);
    if (rc)
        goto pmp_fail;

    /* recover links */
    rc = ata_eh_recover(ap, ops->pmp_prereset, ops->pmp_softreset,
                ops->pmp_hardreset, ops->pmp_postreset, &link);
    if (rc)
        goto link_fail;

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

    /*
     * If LPM is active on any fan-out port, hotplug wouldn't
     * work.  Return w/ PHY event notification disabled.
     */
    ata_for_each_link(link, ap, EDGE)
        if (link->lpm_policy > ATA_LPM_MAX_POWER)
            return 0;

    /*
     * Connection status might have changed while resetting other
     * links, enable notification and check SATA_PMP_GSCR_ERROR
     * before returning.
     */

    /* enable notification */
    if (pmp_dev->flags & ATA_DFLAG_AN) {
        gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;

        err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
                      gscr[SATA_PMP_GSCR_FEAT_EN]);
        if (err_mask) {
            ata_dev_err(pmp_dev,
                    "failed to write PMP_FEAT_EN (Emask=0x%x)\n",
                    err_mask);
            rc = -EIO;
            goto pmp_fail;
        }
    }

    /* check GSCR_ERROR */
    err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
    if (err_mask) {
        ata_dev_err(pmp_dev,
                "failed to read PMP_GSCR_ERROR (Emask=0x%x)\n",
                err_mask);
        rc = -EIO;
        goto pmp_fail;
    }

    cnt = 0;
    ata_for_each_link(link, ap, EDGE) {
        if (!(gscr_error & (1 << link->pmp)))
            continue;

        if (sata_pmp_handle_link_fail(link, link_tries)) {
            ata_ehi_hotplugged(&link->eh_context.i);
            cnt++;
        } else {
            ata_link_warn(link,
                "PHY status changed but maxed out on retries, giving up\n");
            ata_link_warn(link,
                "Manually issue scan to resume this link\n");
        }
    }

    if (cnt) {
        ata_port_info(ap,
            "PMP SError.N set for some ports, repeating recovery\n");
        goto retry;
    }

    return 0;

 link_fail:
    if (sata_pmp_handle_link_fail(link, link_tries)) {
        pmp_ehc->i.action |= ATA_EH_RESET;
        goto retry;
    }

    /* fall through */
 pmp_fail:
    /* Control always ends up here after detaching PMP.  Shut up
     * and return if we're unloading.
     */
    if (ap->pflags & ATA_PFLAG_UNLOADING)
        return rc;

    if (!sata_pmp_attached(ap))
        goto retry;

    if (--pmp_tries) {
        pmp_ehc->i.action |= ATA_EH_RESET;
        goto retry;
    }

    ata_port_err(ap, "failed to recover PMP after %d tries, giving up\n",
             ATA_EH_PMP_TRIES);
    sata_pmp_detach(pmp_dev);
    ata_dev_disable(pmp_dev);

    return rc;
}

void sata_pmp_error_handler(struct ata_port *ap)
{
    ata_eh_autopsy(ap);
    ata_eh_report(ap);
    sata_pmp_eh_recover(ap);
    ata_eh_finish(ap);
}

EXPORT_SYMBOL_GPL(sata_pmp_port_ops);
EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
EXPORT_SYMBOL_GPL(sata_pmp_error_handler);