--- /dev/null
+/*
+ * 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);
+}