libata: implement LPM support for port multipliers

Port multipliers can do DIPM on fan-out links fine.  Implement support
for it.  Tested w/ SIMG 57xx and marvell PMPs.  Both the host and
fan-out links enter power save modes nicely.

SIMG 37xx and 47xx report link offline on SStatus causing EH to detach
the devices.  Blacklisted.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

3 files changed, 67 insertions, 10 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index a645cd3ab163..06a4db1ec10e 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -3232,7 +3232,7 @@ static int ata_eh_maybe_retry_flush(struct ata_device *dev)
 static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
                           struct ata_device **r_failed_dev)
 {
-        struct ata_port *ap = link->ap;
+        struct ata_port *ap = ata_is_host_link(link) ? link->ap : NULL;
         struct ata_eh_context *ehc = &link->eh_context;
         struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL;
         unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
@@ -3278,9 +3278,12 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
                 }
         }
 
-        rc = ap->ops->set_lpm(link, policy, hints);
-        if (!rc && ap->slave_link)
-                rc = ap->ops->set_lpm(ap->slave_link, policy, hints);
+        if (ap) {
+                rc = ap->ops->set_lpm(link, policy, hints);
+                if (!rc && ap->slave_link)
+                        rc = ap->ops->set_lpm(ap->slave_link, policy, hints);
+        } else
+                rc = sata_pmp_set_lpm(link, policy, hints);
 
         /*
          * Attribute link config failure to the first (LPM) enabled
@@ -3412,8 +3415,14 @@ static int ata_eh_schedule_probe(struct ata_device *dev)
         ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
         /* the link maybe in a deep sleep, wake it up */
-        if (link->lpm_policy > ATA_LPM_MAX_POWER)
-                link->ap->ops->set_lpm(link, ATA_LPM_MAX_POWER, ATA_LPM_EMPTY);
+        if (link->lpm_policy > ATA_LPM_MAX_POWER) {
+                if (ata_is_host_link(link))
+                        link->ap->ops->set_lpm(link, ATA_LPM_MAX_POWER,
+                                               ATA_LPM_EMPTY);
+                else
+                        sata_pmp_set_lpm(link, ATA_LPM_MAX_POWER,
+                                         ATA_LPM_EMPTY);
+        }
 
         /* Record and count probe trials on the ering.  The specific
          * error mask used is irrelevant.  Because a successful device
diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c
index 505470237d79..3120596d4afc 100644
--- a/drivers/ata/libata-pmp.c
+++ b/drivers/ata/libata-pmp.c
@@ -186,6 +186,27 @@ int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
 }
 
 /**
+ *      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
@@ -365,6 +386,9 @@ static void sata_pmp_quirks(struct ata_port *ap)
         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 and SRST
                          * times out under certain configurations.
                          */
@@ -380,6 +404,9 @@ static void sata_pmp_quirks(struct ata_port *ap)
         } 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;
@@ -392,6 +419,9 @@ static void sata_pmp_quirks(struct ata_port *ap)
         } 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
@@ -952,15 +982,25 @@ static int sata_pmp_eh_recover(struct ata_port *ap)
         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);
 
+        /*
+         * 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;
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 55a6f413a550..7c070a4b1c08 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -176,6 +176,8 @@ extern int ata_ering_map(struct ata_ering *ering,
 #ifdef CONFIG_SATA_PMP
 extern int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *val);
 extern int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val);
+extern int sata_pmp_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
+                            unsigned hints);
 extern int sata_pmp_attach(struct ata_device *dev);
 #else /* CONFIG_SATA_PMP */
 static inline int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *val)
@@ -188,6 +190,12 @@ static inline int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
         return -EINVAL;
 }
 
+static inline int sata_pmp_set_lpm(struct ata_link *link,
+                                   enum ata_lpm_policy policy, unsigned hints)
+{
+        return -EINVAL;
+}
+
 static inline int sata_pmp_attach(struct ata_device *dev)
 {
         return -EINVAL;