/*
 * libata-pmp.c - libata port multiplier support
 *
 * Copyright (c) 2007  SUSE Linux Products GmbH
 * Copyright (c) 2007  Tejun Heo <teheo@suse.de>
 *
 * 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,
};

/**
 *      sata_pmp_read - read PMP register
 *      @link: link to read PMP register for
 *      @reg: register to read
 *      @r_val: resulting value
 *
 *      Read PMP register.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, AC_ERR_* mask on failure.
 */
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;
}

/**
 *      sata_pmp_write - write PMP register
 *      @link: link to write PMP register for
 *      @reg: register to write
 *      @r_val: value to write
 *
 *      Write PMP register.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, AC_ERR_* mask on failure.
 */
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);
}

/**
 *      sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
 *      @qc: ATA command in question
 *
 *      A host which has command switching PMP support cannot issue
 *      commands to multiple links simultaneously.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 *
 *      RETURNS:
 *      ATA_DEFER_* if deferring is needed, 0 otherwise.
 */
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;
}

/**
 *      sata_pmp_scr_read - read PSCR
 *      @link: ATA link to read PSCR for
 *      @reg: PSCR to read
 *      @r_val: resulting value
 *
 *      Read PSCR @reg into @r_val for @link, to be called from
 *      ata_scr_read().
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
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;
}

/**
 *      sata_pmp_scr_write - write PSCR
 *      @link: ATA link to write PSCR for
 *      @reg: PSCR to write
 *      @val: value to be written
 *
 *      Write @val to PSCR @reg for @link, to be called from
 *      ata_scr_write() and ata_scr_write_flush().
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
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;
}

/**
 *      sata_pmp_set_lpm - configure LPM for a PMP link
 *      @link: PMP link to configure LPM for
 *      @policy: target LPM policy
 *      @hints: LPM hints
 *
 *      Configure LPM for @link.  This function will contain any PMP
 *      specific workarounds if necessary.
 *
 *      LOCKING:
 *      EH context.
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int sata_pmp_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
                     unsigned hints)
{
        return sata_link_scr_lpm(link, policy, true);
}

/**
 *      sata_pmp_read_gscr - read GSCR block of SATA PMP
 *      @dev: PMP device
 *      @gscr: buffer to read GSCR block into
 *
 *      Read selected PMP GSCRs from the PMP at @dev.  This will serve
 *      as configuration and identification info for the PMP.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
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;
                }
        }
}

/**
 *      sata_pmp_attach - attach a SATA PMP device
 *      @dev: SATA PMP device to attach
 *
 *      Configure and attach SATA PMP device @dev.  This function is
 *      also responsible for allocating and initializing PMP links.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
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);

        ata_acpi_associate_sata_port(ap);

        return 0;

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

/**
 *      sata_pmp_detach - detach a SATA PMP device
 *      @dev: SATA PMP device to detach
 *
 *      Detach SATA PMP device @dev.  This function is also
 *      responsible for deconfiguring PMP links.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 */
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);

        ata_acpi_associate_sata_port(ap);
}

/**
 *      sata_pmp_same_pmp - does new GSCR matches the configured PMP?
 *      @dev: PMP device to compare against
 *      @new_gscr: GSCR block of the new device
 *
 *      Compare @new_gscr against @dev and determine whether @dev is
 *      the PMP described by @new_gscr.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      1 if @dev matches @new_gscr, 0 otherwise.
 */
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;
}

/**
 *      sata_pmp_revalidate - revalidate SATA PMP
 *      @dev: PMP device to revalidate
 *      @new_class: new class code
 *
 *      Re-read GSCR block and make sure @dev is still attached to the
 *      port and properly configured.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
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;
}

/**
 *      sata_pmp_revalidate_quick - revalidate SATA PMP quickly
 *      @dev: PMP device to revalidate
 *
 *      Make sure the attached PMP is accessible.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
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;
}

/**
 *      sata_pmp_eh_recover_pmp - recover PMP
 *      @ap: ATA port PMP is attached to
 *      @prereset: prereset method (can be NULL)
 *      @softreset: softreset method
 *      @hardreset: hardreset method
 *      @postreset: postreset method (can be NULL)
 *
 *      Recover PMP attached to @ap.  Recovery procedure is somewhat
 *      similar to that of ata_eh_recover() except that reset should
 *      always be performed in hard->soft sequence and recovery
 *      failure results in PMP detachment.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
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;
}

/**
 *      sata_pmp_eh_recover - recover PMP-enabled port
 *      @ap: ATA port to recover
 *
 *      Drive EH recovery operation for PMP enabled port @ap.  This
 *      function recovers host and PMP ports with proper retrials and
 *      fallbacks.  Actual recovery operations are performed using
 *      ata_eh_recover() and sata_pmp_eh_recover_pmp().
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
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;
}

/**
 *      sata_pmp_error_handler - do standard error handling for PMP-enabled host
 *      @ap: host port to handle error for
 *
 *      Perform standard error handling sequence for PMP-enabled host
 *      @ap.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 */
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);