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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Stanley Chu <stanley.chu@mediatek.com>,
        Peter Wang <peter.wang@mediatek.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 171/252] scsi: ufs: ufs-mediatek: Fix power down spec violation
Date:   Mon, 31 May 2021 15:13:56 +0200
Message-Id: <20210531130703.818410766@linuxfoundation.org>
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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 09d2ac20508b..aace13399a7f 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -824,6 +824,7 @@ 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);
@@ -844,6 +845,9 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 		ufs_mtk_vreg_set_lpm(hba, true);
 	}
 
+	if (ufshcd_is_link_off(hba))
+		ufs_mtk_device_reset_ctrl(0, res);
+
 	return 0;
 }
 
-- 
2.30.2