[PATCH v3 2/2] scsi: ufs-mediatek: add error recovery for suspend and resume

[Stanley Chu]

Once fail happens during suspend and resume flow if the desired low
power link state is H8, link recovery is required for MediaTek UFS
controller.

For resume flow, since power and clocks are already enabled before
invoking vendor's resume callback, simply using ufshcd_link_recovery()
inside callback is fine.

For suspend flow, the device power enters low power mode or is disabled
before suspend callback, thus ufshcd_link_recovery() can not be directly
used in vendor callback. One solution is to set the link to off state
and then ufshcd_host_reset_and_restore() will be executed by ufshcd_suspend().

Signed-off-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Reviewed-by: Avri Altman <avri.altman@xxxxxxx>
---
 drivers/scsi/ufs/ufs-mediatek.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 40a66b31b31f..673c16596fb2 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -499,8 +499,15 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 
 	if (ufshcd_is_link_hibern8(hba)) {
 		err = ufs_mtk_link_set_lpm(hba);
-		if (err)
+		if (err) {
+			/*
+			 * Set link as off state enforcedly to trigger
+			 * ufshcd_host_reset_and_restore() in ufshcd_suspend()
+			 * for completed host reset.
+			 */
+			ufshcd_set_link_off(hba);
 			return -EAGAIN;
+		}
 	}
 
 	if (!ufshcd_is_link_active(hba))
@@ -519,8 +526,10 @@ static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 
 	if (ufshcd_is_link_hibern8(hba)) {
 		err = ufs_mtk_link_set_hpm(hba);
-		if (err)
+		if (err) {
+			err = ufshcd_link_recovery(hba);
 			return err;
+		}
 	}
 
 	return 0;
-- 
2.18.0