libata-pmp: implement Port Multiplier support

[mirror_ubuntu-artful-kernel.git] / drivers / ata / libata-pmp.c

/*
 * 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/libata.h>
#include "libata.h"

/**
 *      sata_pmp_read - read PMP register
 *      @link: link to read PMP register for
 *      @reg: register to read
 *      @r_val: resulting value
 *
 *      Wrapper around ap->ops->pmp_read to make it easier to call and
 *      nomarlize error return value.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
static 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;
        int rc;

        might_sleep();

        rc = ap->ops->pmp_read(pmp_dev, link->pmp, reg, r_val);
        if (rc)
                rc = -EIO;
        return rc;
}

/**
 *      sata_pmp_write - write PMP register
 *      @link: link to write PMP register for
 *      @reg: register to write
 *      @r_val: value to write
 *
 *      Wrapper around ap->ops->pmp_write to make it easier to call
 *      and nomarlize error return value.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
static 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;
        int rc;

        might_sleep();

        rc = ap->ops->pmp_write(pmp_dev, link->pmp, reg, val);
        if (rc)
                rc = -EIO;
        return rc;
}

/**
 *      sata_pmp_read_init_tf - initialize TF for PMP read
 *      @tf: taskfile to initialize
 *      @dev: PMP dev
 *      @pmp: port multiplier port number
 *      @reg: register to read
 *
 *      Initialize @tf for PMP read command.
 *
 *      LOCKING:
 *      None.
 */
void sata_pmp_read_init_tf(struct ata_taskfile *tf,
                           struct ata_device *dev, int pmp, int reg)
{
        ata_tf_init(dev, tf);
        tf->command = ATA_CMD_PMP_READ;
        tf->protocol = ATA_PROT_NODATA;
        tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
        tf->feature = reg;
        tf->device = pmp;
}

/**
 *      sata_pmp_read_val - extract PMP read result from TF
 *      @tf: target TF
 *
 *      Determine PMP read result from @tf.
 *
 *      LOCKING:
 *      None.
 */
u32 sata_pmp_read_val(const struct ata_taskfile *tf)
{
        return tf->nsect | tf->lbal << 8 | tf->lbam << 16 | tf->lbah << 24;
}

/**
 *      sata_pmp_read_init_tf - initialize TF for PMP write
 *      @tf: taskfile to initialize
 *      @dev: PMP dev
 *      @pmp: port multiplier port number
 *      @reg: register to read
 *      @val: value to write
 *
 *      Initialize @tf for PMP write command.
 *
 *      LOCKING:
 *      None.
 */
void sata_pmp_write_init_tf(struct ata_taskfile *tf,
                            struct ata_device *dev, int pmp, int reg, u32 val)
{
        ata_tf_init(dev, tf);
        tf->command = ATA_CMD_PMP_WRITE;
        tf->protocol = ATA_PROT_NODATA;
        tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
        tf->feature = reg;
        tf->device = pmp;
        tf->nsect = val & 0xff;
        tf->lbal = (val >> 8) & 0xff;
        tf->lbam = (val >> 16) & 0xff;
        tf->lbah = (val >> 24) & 0xff;
}

/**
 *      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)
{
        if (reg > SATA_PMP_PSCR_CONTROL)
                return -EINVAL;

        return sata_pmp_read(link, reg, r_val);
}

/**
 *      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)
{
        if (reg > SATA_PMP_PSCR_CONTROL)
                return -EINVAL;

        return sata_pmp_write(link, reg, val);
}

/**
 *      sata_pmp_std_prereset - prepare PMP link for reset
 *      @link: link to be reset
 *      @deadline: deadline jiffies for the operation
 *
 *      @link is about to be reset.  Initialize it.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline)
{
        struct ata_eh_context *ehc = &link->eh_context;
        const unsigned long *timing = sata_ehc_deb_timing(ehc);
        int rc;

        /* force HRST? */
        if (link->flags & ATA_LFLAG_NO_SRST)
                ehc->i.action |= ATA_EH_HARDRESET;

        /* handle link resume */
        if ((ehc->i.flags & ATA_EHI_RESUME_LINK) &&
            (link->flags & ATA_LFLAG_HRST_TO_RESUME))
                ehc->i.action |= ATA_EH_HARDRESET;

        /* if we're about to do hardreset, nothing more to do */
        if (ehc->i.action & ATA_EH_HARDRESET)
                return 0;

        /* resume link */
        rc = sata_link_resume(link, timing, deadline);
        if (rc) {
                /* phy resume failed */
                ata_link_printk(link, KERN_WARNING, "failed to resume link "
                                "for reset (errno=%d)\n", rc);
                return rc;
        }

        /* clear SError bits including .X which blocks the port when set */
        rc = sata_scr_write(link, SCR_ERROR, 0xffffffff);
        if (rc) {
                ata_link_printk(link, KERN_ERR,
                                "failed to clear SError (errno=%d)\n", rc);
                return rc;
        }

        return 0;
}

/**
 *      sata_pmp_std_hardreset - standard hardreset method for PMP link
 *      @link: link to be reset
 *      @class: resulting class of attached device
 *      @deadline: deadline jiffies for the operation
 *
 *      Hardreset PMP port @link.  Note that this function doesn't
 *      wait for BSY clearance.  There simply isn't a generic way to
 *      wait the event.  Instead, this function return -EAGAIN thus
 *      telling libata-EH to followup with softreset.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class,
                           unsigned long deadline)
{
        const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
        u32 tmp;
        int rc;

        DPRINTK("ENTER\n");

        /* do hardreset */
        rc = sata_link_hardreset(link, timing, deadline);
        if (rc) {
                ata_link_printk(link, KERN_ERR,
                                "COMRESET failed (errno=%d)\n", rc);
                goto out;
        }

        /* clear SError bits including .X which blocks the port when set */
        rc = sata_scr_write(link, SCR_ERROR, 0xffffffff);
        if (rc) {
                ata_link_printk(link, KERN_ERR, "failed to clear SError "
                                "during hardreset (errno=%d)\n", rc);
                goto out;
        }

        /* if device is present, follow up with srst to wait for !BSY */
        if (ata_link_online(link))
                rc = -EAGAIN;
 out:
        /* if SCR isn't accessible, we need to reset the PMP */
        if (rc && rc != -EAGAIN && sata_scr_read(link, SCR_STATUS, &tmp))
                rc = -ERESTART;

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

/**
 *      ata_std_postreset - standard postreset method for PMP link
 *      @link: the target ata_link
 *      @classes: classes of attached devices
 *
 *      This function is invoked after a successful reset.  Note that
 *      the device might have been reset more than once using
 *      different reset methods before postreset is invoked.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class)
{
        u32 serror;

        DPRINTK("ENTER\n");

        /* clear SError */
        if (sata_scr_read(link, SCR_ERROR, &serror) == 0)
                sata_scr_write(link, SCR_ERROR, serror);

        /* print link status */
        sata_print_link_status(link);

        DPRINTK("EXIT\n");
}

/**
 *      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, rc;

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

                rc = sata_pmp_read(dev->link, reg, &gscr[reg]);
                if (rc) {
                        ata_dev_printk(dev, KERN_ERR, "failed to read "
                                       "PMP GSCR[%d] (errno=%d)\n", reg, rc);
                        return rc;
                }
        }

        return 0;
}

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

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

static int sata_pmp_configure(struct ata_device *dev, int print_info)
{
        struct ata_port *ap = dev->link->ap;
        u32 *gscr = dev->gscr;
        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 */
        rc = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN, SERR_PHYRDY_CHG);
        if (rc) {
                reason = "failed to write GSCR_ERROR_EN";
                goto fail;
        }

        /* turn off notification till fan-out ports are reset and configured */
        if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
                gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;

                rc = sata_pmp_write(dev->link, SATA_PMP_GSCR_FEAT_EN,
                                    gscr[SATA_PMP_GSCR_FEAT_EN]);
                if (rc) {
                        reason = "failed to write GSCR_FEAT_EN";
                        goto fail;
                }
        }

        if (print_info) {
                ata_dev_printk(dev, KERN_INFO, "Port Multiplier %s, "
                               "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
                               sata_pmp_spec_rev_str(gscr),
                               sata_pmp_gscr_vendor(gscr),
                               sata_pmp_gscr_devid(gscr),
                               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_printk(dev, KERN_INFO,
                                "Asynchronous notification not supported, "
                                "hotplug won't\n         work on fan-out "
                                "ports. Use warm-plug instead.\n");
        }

        return 0;

 fail:
        ata_dev_printk(dev, KERN_ERR,
                       "failed to configure Port Multiplier (%s)\n", reason);
        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;

        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 < 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 |= 1;
                ehc->i.action |= ATA_EH_SOFTRESET;
                ehc->i.flags |= ATA_EHI_RESUME_LINK;
        }

        return 0;
}

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_port_for_each_link(link, ap) {
                        /* SError.N need a kick in the ass to get working */
                        link->flags |= ATA_LFLAG_HRST_TO_RESUME;

                        /* 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_port_for_each_link(link, ap) {
                        /* SError.N need a kick in the ass to get working */
                        link->flags |= ATA_LFLAG_HRST_TO_RESUME;

                        /* 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_port_for_each_link(link, ap) {
                        /* SError.N need a kick in the ass to get working */
                        link->flags |= ATA_LFLAG_HRST_TO_RESUME;

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

                        /* The config device, which can be either at
                         * port 0 or 5, locks up on SRST.
                         */
                        if (link->pmp == 0 || 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 == 0x11ab && devid == 0x4140) {
                /* Marvell 88SM4140 quirks.  Fan-out ports require PHY
                 * reset to work; other than that, it behaves very
                 * nicely.
                 */
                ata_port_for_each_link(link, ap)
                        link->flags |= ATA_LFLAG_HRST_TO_RESUME;
        }
}

/**
 *      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 (!(ap->flags & ATA_FLAG_PMP)) {
                ata_dev_printk(dev, KERN_ERR,
                               "host does not support Port Multiplier\n");
                return -EINVAL;
        }

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

        if (dev->devno) {
                ata_dev_printk(dev, KERN_ERR,
                               "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_printk(dev, KERN_INFO,
                               "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_port_for_each_link(tlink, ap)
                sata_link_init_spd(tlink);

        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_printk(dev, KERN_INFO, "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_port_for_each_link(tlink, ap)
                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);
}

/**
 *      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_printk(dev, KERN_INFO, "Port Multiplier "
                               "vendor mismatch '0x%x' != '0x%x'\n",
                               old_vendor, new_vendor);
                return 0;
        }

        if (old_devid != new_devid) {
                ata_dev_printk(dev, KERN_INFO, "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_printk(dev, KERN_INFO, "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_printk(dev, KERN_ERR,
                       "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)
{
        u32 prod_id;
        int rc;

        rc = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
        if (rc) {
                ata_dev_printk(dev, KERN_ERR, "failed to read PMP product ID\n");
                return rc;
        }

        if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
                ata_dev_printk(dev, KERN_ERR, "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_MASK) {
                struct ata_link *tlink;

                ata_eh_freeze_port(ap);

                /* reset */
                ehc->i.action = ATA_EH_HARDRESET;
                rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
                                  postreset);
                if (rc) {
                        ata_link_printk(link, KERN_ERR,
                                        "failed to reset PMP, giving up\n");
                        goto fail;
                }

                ata_eh_thaw_port(ap);

                /* PMP is reset, SErrors cannot be trusted, scan all */
                ata_port_for_each_link(tlink, ap)
                        ata_ehi_schedule_probe(&tlink->eh_context.i);
        }

        /* 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 |= 1;
                        detach = 1;
                        /* give it just two more chances */
                        tries = min(tries, 2);
                }

                if (tries) {
                        int sleep = ehc->i.flags & ATA_EHI_DID_RESET;

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

                        ata_dev_printk(dev, KERN_WARNING,
                                       "retrying hardreset%s\n",
                                       sleep ? " in 5 secs" : "");
                        if (sleep)
                                ssleep(5);
                        ehc->i.action |= ATA_EH_HARDRESET;
                        goto retry;
                } else {
                        ata_dev_printk(dev, KERN_ERR, "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_port_for_each_link(link, ap) {
                if (!(link->flags & ATA_LFLAG_DISABLED))
                        continue;

                spin_unlock_irqrestore(ap->lock, flags);

                /* Some PMPs require hardreset sequence to get
                 * SError.N working.
                 */
                if ((link->flags & ATA_LFLAG_HRST_TO_RESUME) &&
                    (link->eh_context.i.flags & ATA_EHI_RESUME_LINK))
                        sata_link_hardreset(link, sata_deb_timing_normal,
                                            jiffies + ATA_TMOUT_INTERNAL_QUICK);

                /* unconditionally clear SError.N */
                rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
                if (rc) {
                        ata_link_printk(link, KERN_ERR, "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_printk(link, KERN_WARNING,
                        "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
 *      @prereset: prereset method (can be NULL)
 *      @softreset: softreset method
 *      @hardreset: hardreset method
 *      @postreset: postreset method (can be NULL)
 *      @pmp_prereset: PMP prereset method (can be NULL)
 *      @pmp_softreset: PMP softreset method (can be NULL)
 *      @pmp_hardreset: PMP hardreset method (can be NULL)
 *      @pmp_postreset: PMP postreset method (can be NULL)
 *
 *      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,
                ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
                ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
                ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
                ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset)
{
        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;
        struct ata_link *link;
        struct ata_device *dev;
        u32 gscr_error, sntf;
        int cnt, rc;

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

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

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

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

                /* fall through */
        }

        /* recover pmp */
        rc = sata_pmp_eh_recover_pmp(ap, prereset, softreset, hardreset,
                                     postreset);
        if (rc)
                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, pmp_prereset, pmp_softreset, pmp_hardreset,
                            pmp_postreset, &link);
        if (rc)
                goto link_fail;

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

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

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

                rc = sata_pmp_write(pmp_dev->link, SATA_PMP_GSCR_FEAT_EN,
                                    pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN]);
                if (rc) {
                        ata_dev_printk(pmp_dev, KERN_ERR,
                                       "failed to write PMP_FEAT_EN\n");
                        goto pmp_fail;
                }
        }

        /* check GSCR_ERROR */
        rc = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
        if (rc) {
                ata_dev_printk(pmp_dev, KERN_ERR,
                               "failed to read PMP_GSCR_ERROR\n");
                goto pmp_fail;
        }

        cnt = 0;
        ata_port_for_each_link(link, ap) {
                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_printk(link, KERN_WARNING,
                                "PHY status changed but maxed out on retries, "
                                "giving up\n");
                        ata_link_printk(link, KERN_WARNING,
                                "Manully issue scan to resume this link\n");
                }
        }

        if (cnt) {
                ata_port_printk(ap, KERN_INFO, "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_HARDRESET;
                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 (!ap->nr_pmp_links)
                goto retry;

        if (--pmp_tries) {
                ata_port_printk(ap, KERN_WARNING,
                                "failed to recover PMP, retrying in 5 secs\n");
                pmp_ehc->i.action |= ATA_EH_HARDRESET;
                ssleep(5);
                goto retry;
        }

        ata_port_printk(ap, KERN_ERR,
                        "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_do_eh - do standard error handling for PMP-enabled host
 *      @ap: host port to handle error for
 *      @prereset: prereset method (can be NULL)
 *      @softreset: softreset method
 *      @hardreset: hardreset method
 *      @postreset: postreset method (can be NULL)
 *      @pmp_prereset: PMP prereset method (can be NULL)
 *      @pmp_softreset: PMP softreset method (can be NULL)
 *      @pmp_hardreset: PMP hardreset method (can be NULL)
 *      @pmp_postreset: PMP postreset method (can be NULL)
 *
 *      Perform standard error handling sequence for PMP-enabled host
 *      @ap.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 */
void sata_pmp_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,
                ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
                ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset)
{
        ata_eh_autopsy(ap);
        ata_eh_report(ap);
        sata_pmp_eh_recover(ap, prereset, softreset, hardreset, postreset,
                            pmp_prereset, pmp_softreset, pmp_hardreset,
                            pmp_postreset);
        ata_eh_finish(ap);
}