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From: Stanley Chu <stanley.chu@mediatek.com>
To: <linux-scsi@vger.kernel.org>, <martin.petersen@oracle.com>,
	<avri.altman@wdc.com>, <alim.akhtar@samsung.com>,
	<jejb@linux.ibm.com>, <bvanassche@acm.org>
Cc: <beanhuo@micron.com>, <asutoshd@codeaurora.org>,
	<cang@codeaurora.org>, <matthias.bgg@gmail.com>,
	<linux-mediatek@lists.infradead.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <kuohong.wang@mediatek.com>,
	<peter.wang@mediatek.com>, <chun-hung.wu@mediatek.com>,
	<andy.teng@mediatek.com>, <chaotian.jing@mediatek.com>,
	<cc.chou@mediatek.com>, Stanley Chu <stanley.chu@mediatek.com>
Subject: [PATCH v1] scsi: ufs-mediatek: Prevent LPM operation on undeclared VCC
Date: Fri, 24 Jul 2020 22:16:27 +0800
Message-ID: <20200724141627.20094-1-stanley.chu@mediatek.com> (raw)

In some platforms, VCC regulator may not be declared in device tree
to keep itself "always-on". In this case, hba->vreg_info.vcc is NULL
and shall not be operated during any flow.

Prevent possible NULL hba->vreg_info.vcc access in LPM mode by checking
if it is valid first.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
---
 drivers/scsi/ufs/ufs-mediatek.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 31af8b3d2b53..66223fe200fc 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -574,7 +574,7 @@ static int ufs_mtk_link_set_lpm(struct ufs_hba *hba)
 
 static void ufs_mtk_vreg_set_lpm(struct ufs_hba *hba, bool lpm)
 {
-	if (!hba->vreg_info.vccq2)
+	if (!hba->vreg_info.vccq2 || !hba->vreg_info.vcc)
 		return;
 
 	if (lpm & !hba->vreg_info.vcc->enabled)
-- 
2.18.0

             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24 14:16 Stanley Chu [this message]
2020-07-27 10:56 ` Avri Altman
2020-07-29  4:10 ` Martin K. Petersen

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