scsi: ufs: Add retry flow for failed HBA enabling

Once HBA enabling has failed, add retry mechanism and allow vendors to
apply specific tweaks before the next retry. For example, vendors can do
vendor-specific host reset flow in variant function
"ufshcd_vops_hce_enable_notify()".

Link: https://lore.kernel.org/r/20201112054537.22494-1-stanley.chu@mediatek.comReviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -4328,8 +4328,10 @@ static inline void ufshcd_hba_stop(struct ufs_hba *hba)
  */
 static int ufshcd_hba_execute_hce(struct ufs_hba *hba)
 {
-	int retry;
+	int retry_outer = 3;
+	int retry_inner;
 
+start:
 	if (!ufshcd_is_hba_active(hba))
 		/* change controller state to "reset state" */
 		ufshcd_hba_stop(hba);
@@ -4355,13 +4357,17 @@ static int ufshcd_hba_execute_hce(struct ufs_hba *hba)
 	ufshcd_delay_us(hba->vps->hba_enable_delay_us, 100);
 
 	/* wait for the host controller to complete initialization */
-	retry = 50;
+	retry_inner = 50;
 	while (ufshcd_is_hba_active(hba)) {
-		if (retry) {
-			retry--;
+		if (retry_inner) {
+			retry_inner--;
 		} else {
 			dev_err(hba->dev,
 				"Controller enable failed\n");
+			if (retry_outer) {
+				retry_outer--;
+				goto start;
+			}
 			return -EIO;
 		}
 		usleep_range(1000, 1100);