3 files changed, 105 insertions, 7 deletions

diff --git a/drivers/scsi/scsi_sas_internal.h b/drivers/scsi/scsi_sas_internal.h
index 998cb5be6833..6266a5d73d0f 100644
--- a/drivers/scsi/scsi_sas_internal.h
+++ b/drivers/scsi/scsi_sas_internal.h
@@ -5,7 +5,7 @@
 #define SAS_PHY_ATTRS           17
 #define SAS_PORT_ATTRS          1
 #define SAS_RPORT_ATTRS         7
-#define SAS_END_DEV_ATTRS       3
+#define SAS_END_DEV_ATTRS       5
 #define SAS_EXPANDER_ATTRS      7
 
 struct sas_internal {
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index f27e52d963d3..927e99cb7225 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -155,6 +155,17 @@ static struct {
 sas_bitfield_name_search(linkspeed, sas_linkspeed_names)
 sas_bitfield_name_set(linkspeed, sas_linkspeed_names)
 
+static struct sas_end_device *sas_sdev_to_rdev(struct scsi_device *sdev)
+{
+        struct sas_rphy *rphy = target_to_rphy(sdev->sdev_target);
+        struct sas_end_device *rdev;
+
+        BUG_ON(rphy->identify.device_type != SAS_END_DEVICE);
+
+        rdev = rphy_to_end_device(rphy);
+        return rdev;
+}
+
 static void sas_smp_request(struct request_queue *q, struct Scsi_Host *shost,
                             struct sas_rphy *rphy)
 {
@@ -358,6 +369,85 @@ void sas_remove_host(struct Scsi_Host *shost)
 }
 EXPORT_SYMBOL(sas_remove_host);
 
+/**
+ * sas_tlr_supported - checking TLR bit in vpd 0x90
+ * @sdev: scsi device struct
+ *
+ * Check Transport Layer Retries are supported or not.
+ * If vpd page 0x90 is present, TRL is supported.
+ *
+ */
+unsigned int
+sas_tlr_supported(struct scsi_device *sdev)
+{
+        const int vpd_len = 32;
+        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
+        char *buffer = kzalloc(vpd_len, GFP_KERNEL);
+        int ret = 0;
+
+        if (scsi_get_vpd_page(sdev, 0x90, buffer, vpd_len))
+                goto out;
+
+        /*
+         * Magic numbers: the VPD Protocol page (0x90)
+         * has a 4 byte header and then one entry per device port
+         * the TLR bit is at offset 8 on each port entry
+         * if we take the first port, that's at total offset 12
+         */
+        ret = buffer[12] & 0x01;
+
+ out:
+        kfree(buffer);
+        rdev->tlr_supported = ret;
+        return ret;
+
+}
+EXPORT_SYMBOL_GPL(sas_tlr_supported);
+
+/**
+ * sas_disable_tlr - setting TLR flags
+ * @sdev: scsi device struct
+ *
+ * Seting tlr_enabled flag to 0.
+ *
+ */
+void
+sas_disable_tlr(struct scsi_device *sdev)
+{
+        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
+
+        rdev->tlr_enabled = 0;
+}
+EXPORT_SYMBOL_GPL(sas_disable_tlr);
+
+/**
+ * sas_enable_tlr - setting TLR flags
+ * @sdev: scsi device struct
+ *
+ * Seting tlr_enabled flag 1.
+ *
+ */
+void sas_enable_tlr(struct scsi_device *sdev)
+{
+        unsigned int tlr_supported = 0;
+        tlr_supported  = sas_tlr_supported(sdev);
+
+        if (tlr_supported) {
+                struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
+
+                rdev->tlr_enabled = 1;
+        }
+
+        return;
+}
+EXPORT_SYMBOL_GPL(sas_enable_tlr);
+
+unsigned int sas_is_tlr_enabled(struct scsi_device *sdev)
+{
+        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
+        return rdev->tlr_enabled;
+}
+EXPORT_SYMBOL_GPL(sas_is_tlr_enabled);
 
 /*
  * SAS Phy attributes
@@ -1146,15 +1236,10 @@ sas_rphy_simple_attr(identify.phy_identifier, phy_identifier, "%d\n", u8);
 int sas_read_port_mode_page(struct scsi_device *sdev)
 {
         char *buffer = kzalloc(BUF_SIZE, GFP_KERNEL), *msdata;
-        struct sas_rphy *rphy = target_to_rphy(sdev->sdev_target);
-        struct sas_end_device *rdev;
+        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
         struct scsi_mode_data mode_data;
         int res, error;
 
-        BUG_ON(rphy->identify.device_type != SAS_END_DEVICE);
-
-        rdev = rphy_to_end_device(rphy);
-
         if (!buffer)
                 return -ENOMEM;
 
@@ -1207,6 +1292,10 @@ sas_end_dev_simple_attr(I_T_nexus_loss_timeout, I_T_nexus_loss_timeout,
                         "%d\n", int);
 sas_end_dev_simple_attr(initiator_response_timeout, initiator_response_timeout,
                         "%d\n", int);
+sas_end_dev_simple_attr(tlr_supported, tlr_supported,
+                        "%d\n", int);
+sas_end_dev_simple_attr(tlr_enabled, tlr_enabled,
+                        "%d\n", int);
 
 static DECLARE_TRANSPORT_CLASS(sas_expander_class,
                                "sas_expander", NULL, NULL, NULL);
@@ -1733,6 +1822,8 @@ sas_attach_transport(struct sas_function_template *ft)
         SETUP_END_DEV_ATTRIBUTE(end_dev_ready_led_meaning);
         SETUP_END_DEV_ATTRIBUTE(end_dev_I_T_nexus_loss_timeout);
         SETUP_END_DEV_ATTRIBUTE(end_dev_initiator_response_timeout);
+        SETUP_END_DEV_ATTRIBUTE(end_dev_tlr_supported);
+        SETUP_END_DEV_ATTRIBUTE(end_dev_tlr_enabled);
         i->end_dev_attrs[count] = NULL;
 
         count = 0;
diff --git a/include/scsi/scsi_transport_sas.h b/include/scsi/scsi_transport_sas.h
index 61ad3594aad6..ffeebc34a4f7 100644
--- a/include/scsi/scsi_transport_sas.h
+++ b/include/scsi/scsi_transport_sas.h
@@ -107,6 +107,8 @@ struct sas_end_device {
         struct sas_rphy         rphy;
         /* flags */
         unsigned                ready_led_meaning:1;
+        unsigned                tlr_supported:1;
+        unsigned                tlr_enabled:1;
         /* parameters */
         u16                     I_T_nexus_loss_timeout;
         u16                     initiator_response_timeout;
@@ -181,6 +183,11 @@ extern int sas_phy_add(struct sas_phy *);
 extern void sas_phy_delete(struct sas_phy *);
 extern int scsi_is_sas_phy(const struct device *);
 
+unsigned int sas_tlr_supported(struct scsi_device *);
+unsigned int sas_is_tlr_enabled(struct scsi_device *);
+void sas_disable_tlr(struct scsi_device *);
+void sas_enable_tlr(struct scsi_device *);
+
 extern struct sas_rphy *sas_end_device_alloc(struct sas_port *);
 extern struct sas_rphy *sas_expander_alloc(struct sas_port *, enum sas_device_type);
 void sas_rphy_free(struct sas_rphy *);