scsi: ufs: add retries to dme_peer get and set attribute

The dme_peer get/set attribute commands are prone to errors, therefore
we add three retries for the UIC command sending.  Error code returned
from ufshcd_send_uic_cmd() is checked, and unless it was successful or
the retries have finished, another command will be sent.
Reviewed-by: Gilad Broner <gbroner@codeaurora.org>
Reviewed-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Lee Susman <lsusman@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -68,6 +68,9 @@
 /* Task management command timeout */
 #define TM_CMD_TIMEOUT	100 /* msecs */
 
+/* maximum number of retries for a general UIC command  */
+#define UFS_UIC_COMMAND_RETRIES 3
+
 /* maximum number of link-startup retries */
 #define DME_LINKSTARTUP_RETRIES 3
 
@@ -2182,6 +2185,7 @@ int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
 	};
 	const char *set = action[!!peer];
 	int ret;
+	int retries = UFS_UIC_COMMAND_RETRIES;
 
 	uic_cmd.command = peer ?
 		UIC_CMD_DME_PEER_SET : UIC_CMD_DME_SET;
@@ -2189,10 +2193,18 @@ int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
 	uic_cmd.argument2 = UIC_ARG_ATTR_TYPE(attr_set);
 	uic_cmd.argument3 = mib_val;
 
+	do {
+		/* for peer attributes we retry upon failure */
 		ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
 		if (ret)
-		dev_err(hba->dev, "%s: attr-id 0x%x val 0x%x error code %d\n",
+			dev_dbg(hba->dev, "%s: attr-id 0x%x val 0x%x error code %d\n",
 				set, UIC_GET_ATTR_ID(attr_sel), mib_val, ret);
+	} while (ret && peer && --retries);
+
+	if (!retries)
+		dev_err(hba->dev, "%s: attr-id 0x%x val 0x%x failed %d retries\n",
+				set, UIC_GET_ATTR_ID(attr_sel), mib_val,
+				retries);
 
 	return ret;
 }
@@ -2217,6 +2229,7 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 	};
 	const char *get = action[!!peer];
 	int ret;
+	int retries = UFS_UIC_COMMAND_RETRIES;
 	struct ufs_pa_layer_attr orig_pwr_info;
 	struct ufs_pa_layer_attr temp_pwr_info;
 	bool pwr_mode_change = false;
@@ -2247,14 +2260,19 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 		UIC_CMD_DME_PEER_GET : UIC_CMD_DME_GET;
 	uic_cmd.argument1 = attr_sel;
 
+	do {
+		/* for peer attributes we retry upon failure */
 		ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
-	if (ret) {
-		dev_err(hba->dev, "%s: attr-id 0x%x error code %d\n",
+		if (ret)
+			dev_dbg(hba->dev, "%s: attr-id 0x%x error code %d\n",
 				get, UIC_GET_ATTR_ID(attr_sel), ret);
-		goto out;
-	}
+	} while (ret && peer && --retries);
+
+	if (!retries)
+		dev_err(hba->dev, "%s: attr-id 0x%x failed %d retries\n",
+				get, UIC_GET_ATTR_ID(attr_sel), retries);
 
-	if (mib_val)
+	if (mib_val && !ret)
 		*mib_val = uic_cmd.argument3;
 
 	if (peer && (hba->quirks & UFSHCD_QUIRK_DME_PEER_ACCESS_AUTO_MODE)