[PATCH 5.12 201/296] scsi: ufs: ufs-mediatek: Fix power down spec violation

Greg Kroah-Hartman
2021-05-31T16:37:56Z

From: Peter Wang <peter.wang@mediatek.com>

[ Upstream commit c625b80b9d00f3546722cd77527f9697c8c4c911 ]

As per spec, e.g. JESD220E chapter 7.2, while powering off the UFS device,
RST_N signal should be between VSS(Ground) and VCCQ/VCCQ2. The power down
sequence after fixing:

Power down:

1. Assert RST_N low

2. Turn-off VCC

3. Turn-off VCCQ/VCCQ2

Link: https://lore.kernel.org/r/1620813706-25331-1-git-send-email-peter.wang@mediatek.com
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/ufs/ufs-mediatek.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index a981f261b304..aee3cfc7142a 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -922,6 +922,7 @@ static void ufs_mtk_vreg_set_lpm(struct ufs_hba *hba, bool lpm)
static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
{
int err;
+ struct arm_smccc_res res;

if (ufshcd_is_link_hibern8(hba)) {
err = ufs_mtk_link_set_lpm(hba);
@@ -941,6 +942,9 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
goto fail;
}

+ if (ufshcd_is_link_off(hba))
+ ufs_mtk_device_reset_ctrl(0, res);
+
return 0;
fail:
/*
--
2.30.2