2 files changed, 75 insertions, 28 deletions

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3f2b30db80cc..af29d4c0a416 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -62,6 +62,12 @@
 /* Task management command timeout */
 #define TM_CMD_TIMEOUT  100 /* msecs */
 
+/* maximum number of link-startup retries */
+#define DME_LINKSTARTUP_RETRIES 3
+
+/* maximum number of reset retries before giving up */
+#define MAX_HOST_RESET_RETRIES 5
+
 /* Expose the flag value from utp_upiu_query.value */
 #define MASK_QUERY_UPIU_FLAG_LOC 0xFF
 
@@ -137,6 +143,8 @@ static void ufshcd_tmc_handler(struct ufs_hba *hba);
 static void ufshcd_async_scan(void *data, async_cookie_t cookie);
 static int ufshcd_reset_and_restore(struct ufs_hba *hba);
 static int ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag);
+static void ufshcd_hba_exit(struct ufs_hba *hba);
+static int ufshcd_probe_hba(struct ufs_hba *hba);
 
 /*
  * ufshcd_wait_for_register - wait for register value to change
@@ -2043,6 +2051,9 @@ static int ufshcd_hba_enable(struct ufs_hba *hba)
                 msleep(5);
         }
 
+        /* enable UIC related interrupts */
+        ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
+
         if (hba->vops && hba->vops->hce_enable_notify)
                 hba->vops->hce_enable_notify(hba, POST_CHANGE);
 
@@ -2058,23 +2069,33 @@ static int ufshcd_hba_enable(struct ufs_hba *hba)
 static int ufshcd_link_startup(struct ufs_hba *hba)
 {
         int ret;
+        int retries = DME_LINKSTARTUP_RETRIES;
 
-        /* enable UIC related interrupts */
-        ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
+        do {
+                if (hba->vops && hba->vops->link_startup_notify)
+                        hba->vops->link_startup_notify(hba, PRE_CHANGE);
 
-        if (hba->vops && hba->vops->link_startup_notify)
-                hba->vops->link_startup_notify(hba, PRE_CHANGE);
+                ret = ufshcd_dme_link_startup(hba);
 
-        ret = ufshcd_dme_link_startup(hba);
-        if (ret)
-                goto out;
+                /* check if device is detected by inter-connect layer */
+                if (!ret && !ufshcd_is_device_present(hba)) {
+                        dev_err(hba->dev, "%s: Device not present\n", __func__);
+                        ret = -ENXIO;
+                        goto out;
+                }
 
-        /* check if device is detected by inter-connect layer */
-        if (!ufshcd_is_device_present(hba)) {
-                dev_err(hba->dev, "%s: Device not present\n", __func__);
-                ret = -ENXIO;
+                /*
+                 * DME link lost indication is only received when link is up,
+                 * but we can't be sure if the link is up until link startup
+                 * succeeds. So reset the local Uni-Pro and try again.
+                 */
+                if (ret && ufshcd_hba_enable(hba))
+                        goto out;
+        } while (ret && retries--);
+
+        if (ret)
+                /* failed to get the link up... retire */
                 goto out;
-        }
 
         /* Include any host controller configuration via UIC commands */
         if (hba->vops && hba->vops->link_startup_notify) {
@@ -3139,7 +3160,6 @@ out:
 static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
 {
         int err;
-        async_cookie_t cookie;
         unsigned long flags;
 
         /* Reset the host controller */
@@ -3152,10 +3172,9 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
                 goto out;
 
         /* Establish the link again and restore the device */
-        cookie = async_schedule(ufshcd_async_scan, hba);
-        /* wait for async scan to be completed */
-        async_synchronize_cookie(++cookie);
-        if (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL)
+        err = ufshcd_probe_hba(hba);
+
+        if (!err && (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL))
                 err = -EIO;
 out:
         if (err)
@@ -3177,8 +3196,11 @@ static int ufshcd_reset_and_restore(struct ufs_hba *hba)
 {
         int err = 0;
         unsigned long flags;
+        int retries = MAX_HOST_RESET_RETRIES;
 
-        err = ufshcd_host_reset_and_restore(hba);
+        do {
+                err = ufshcd_host_reset_and_restore(hba);
+        } while (err && --retries);
 
         /*
          * After reset the door-bell might be cleared, complete
@@ -3243,13 +3265,13 @@ static int ufshcd_eh_host_reset_handler(struct scsi_cmnd *cmd)
 }
 
 /**
- * ufshcd_async_scan - asynchronous execution for link startup
- * @data: data pointer to pass to this function
- * @cookie: cookie data
+ * ufshcd_probe_hba - probe hba to detect device and initialize
+ * @hba: per-adapter instance
+ *
+ * Execute link-startup and verify device initialization
  */
-static void ufshcd_async_scan(void *data, async_cookie_t cookie)
+static int ufshcd_probe_hba(struct ufs_hba *hba)
 {
-        struct ufs_hba *hba = (struct ufs_hba *)data;
         int ret;
 
         ret = ufshcd_link_startup(hba);
@@ -3275,7 +3297,26 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
                 pm_runtime_put_sync(hba->dev);
         }
 out:
-        return;
+        /*
+         * If we failed to initialize the device or the device is not
+         * present, turn off the power/clocks etc.
+         */
+        if (ret && !ufshcd_eh_in_progress(hba))
+                ufshcd_hba_exit(hba);
+
+        return ret;
+}
+
+/**
+ * ufshcd_async_scan - asynchronous execution for probing hba
+ * @data: data pointer to pass to this function
+ * @cookie: cookie data
+ */
+static void ufshcd_async_scan(void *data, async_cookie_t cookie)
+{
+        struct ufs_hba *hba = (struct ufs_hba *)data;
+
+        ufshcd_probe_hba(hba);
 }
 
 static struct scsi_host_template ufshcd_driver_template = {
@@ -3631,6 +3672,7 @@ static int ufshcd_hba_init(struct ufs_hba *hba)
         if (err)
                 goto out_disable_vreg;
 
+        hba->is_powered = true;
         goto out;
 
 out_disable_vreg:
@@ -3645,10 +3687,13 @@ out:
 
 static void ufshcd_hba_exit(struct ufs_hba *hba)
 {
-        ufshcd_variant_hba_exit(hba);
-        ufshcd_setup_vreg(hba, false);
-        ufshcd_setup_clocks(hba, false);
-        ufshcd_setup_hba_vreg(hba, false);
+        if (hba->is_powered) {
+                ufshcd_variant_hba_exit(hba);
+                ufshcd_setup_vreg(hba, false);
+                ufshcd_setup_clocks(hba, false);
+                ufshcd_setup_hba_vreg(hba, false);
+                hba->is_powered = false;
+        }
 }
 
 /**
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index bc0f7ed02605..eddb3f3b4139 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -228,6 +228,7 @@ struct ufs_hba_variant_ops {
  * @eh_flags: Error handling flags
  * @intr_mask: Interrupt Mask Bits
  * @ee_ctrl_mask: Exception event control mask
+ * @is_powered: flag to check if HBA is powered
  * @eh_work: Worker to handle UFS errors that require s/w attention
  * @eeh_work: Worker to handle exception events
  * @errors: HBA errors
@@ -283,6 +284,7 @@ struct ufs_hba {
         u32 eh_flags;
         u32 intr_mask;
         u16 ee_ctrl_mask;
+        bool is_powered;
 
         /* Work Queues */
         struct work_struct eh_work;