1 files changed, 93 insertions, 0 deletions

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index adaae345b7c1..4eedb7fafa95 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -3795,6 +3795,79 @@ static void ufshcd_complete_requests(struct ufs_hba *hba)
 }
 
 /**
+ * ufshcd_quirk_dl_nac_errors - This function checks if error handling is
+ *				to recover from the DL NAC errors or not.
+ * @hba: per-adapter instance
+ *
+ * Returns true if error handling is required, false otherwise
+ */
+static bool ufshcd_quirk_dl_nac_errors(struct ufs_hba *hba)
+{
+	unsigned long flags;
+	bool err_handling = true;
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	/*
+	 * UFS_DEVICE_QUIRK_RECOVERY_FROM_DL_NAC_ERRORS only workaround the
+	 * device fatal error and/or DL NAC & REPLAY timeout errors.
+	 */
+	if (hba->saved_err & (CONTROLLER_FATAL_ERROR | SYSTEM_BUS_FATAL_ERROR))
+		goto out;
+
+	if ((hba->saved_err & DEVICE_FATAL_ERROR) ||
+	    ((hba->saved_err & UIC_ERROR) &&
+	     (hba->saved_uic_err & UFSHCD_UIC_DL_TCx_REPLAY_ERROR)))
+		goto out;
+
+	if ((hba->saved_err & UIC_ERROR) &&
+	    (hba->saved_uic_err & UFSHCD_UIC_DL_NAC_RECEIVED_ERROR)) {
+		int err;
+		/*
+		 * wait for 50ms to see if we can get any other errors or not.
+		 */
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+		msleep(50);
+		spin_lock_irqsave(hba->host->host_lock, flags);
+
+		/*
+		 * now check if we have got any other severe errors other than
+		 * DL NAC error?
+		 */
+		if ((hba->saved_err & INT_FATAL_ERRORS) ||
+		    ((hba->saved_err & UIC_ERROR) &&
+		    (hba->saved_uic_err & ~UFSHCD_UIC_DL_NAC_RECEIVED_ERROR)))
+			goto out;
+
+		/*
+		 * As DL NAC is the only error received so far, send out NOP
+		 * command to confirm if link is still active or not.
+		 *   - If we don't get any response then do error recovery.
+		 *   - If we get response then clear the DL NAC error bit.
+		 */
+
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+		err = ufshcd_verify_dev_init(hba);
+		spin_lock_irqsave(hba->host->host_lock, flags);
+
+		if (err)
+			goto out;
+
+		/* Link seems to be alive hence ignore the DL NAC errors */
+		if (hba->saved_uic_err == UFSHCD_UIC_DL_NAC_RECEIVED_ERROR)
+			hba->saved_err &= ~UIC_ERROR;
+		/* clear NAC error */
+		hba->saved_uic_err &= ~UFSHCD_UIC_DL_NAC_RECEIVED_ERROR;
+		if (!hba->saved_uic_err) {
+			err_handling = false;
+			goto out;
+		}
+	}
+out:
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+	return err_handling;
+}
+
+/**
  * ufshcd_err_handler - handle UFS errors that require s/w attention
  * @work: pointer to work structure
  */
@@ -3822,6 +3895,17 @@ static void ufshcd_err_handler(struct work_struct *work)
 
 	/* Complete requests that have door-bell cleared by h/w */
 	ufshcd_complete_requests(hba);
+
+	if (hba->dev_quirks & UFS_DEVICE_QUIRK_RECOVERY_FROM_DL_NAC_ERRORS) {
+		bool ret;
+
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+		/* release the lock as ufshcd_quirk_dl_nac_errors() may sleep */
+		ret = ufshcd_quirk_dl_nac_errors(hba);
+		spin_lock_irqsave(hba->host->host_lock, flags);
+		if (!ret)
+			goto skip_err_handling;
+	}
 	if ((hba->saved_err & INT_FATAL_ERRORS) ||
 	    ((hba->saved_err & UIC_ERROR) &&
 	    (hba->saved_uic_err & (UFSHCD_UIC_DL_PA_INIT_ERROR |
@@ -3897,6 +3981,7 @@ skip_pending_xfer_clear:
 		hba->saved_uic_err = 0;
 	}
 
+skip_err_handling:
 	if (!needs_reset) {
 		hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
 		if (hba->saved_err || hba->saved_uic_err)
@@ -3925,6 +4010,14 @@ static void ufshcd_update_uic_error(struct ufs_hba *hba)
 	reg = ufshcd_readl(hba, REG_UIC_ERROR_CODE_DATA_LINK_LAYER);
 	if (reg & UIC_DATA_LINK_LAYER_ERROR_PA_INIT)
 		hba->uic_error |= UFSHCD_UIC_DL_PA_INIT_ERROR;
+	else if (hba->dev_quirks &
+		   UFS_DEVICE_QUIRK_RECOVERY_FROM_DL_NAC_ERRORS) {
+		if (reg & UIC_DATA_LINK_LAYER_ERROR_NAC_RECEIVED)
+			hba->uic_error |=
+				UFSHCD_UIC_DL_NAC_RECEIVED_ERROR;
+		else if (reg & UIC_DATA_LINK_LAYER_ERROR_TCx_REPLAY_TIMEOUT)
+			hba->uic_error |= UFSHCD_UIC_DL_TCx_REPLAY_ERROR;
+	}
 
 	/* UIC NL/TL/DME errors needs software retry */
 	reg = ufshcd_readl(hba, REG_UIC_ERROR_CODE_NETWORK_LAYER);