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From:   Can Guo <cang@codeaurora.org>
To:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, rnayak@codeaurora.org,
        linux-scsi@vger.kernel.org, kernel-team@android.com,
        saravanak@google.com, salyzyn@google.com, cang@codeaurora.org
Cc:     Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v1 1/1] scsi: ufs: Fix possible unclocked access to auto hibern8 timer register
Date:   Thu,  5 Mar 2020 00:53:07 -0800
Message-Id: <1583398391-14273-1-git-send-email-cang@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Before access auto hibner8 timer register, make sure power and clock are
properly configured to avoid unclocked register access.

Fixes: ba7af5ec5126 ("scsi: ufs: export ufshcd_auto_hibern8_update for vendor usage")
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e987fa3a..5698f11 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -3914,18 +3914,25 @@ int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
 void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit)
 {
 	unsigned long flags;
+	bool update = false;
 
-	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
+	if (!ufshcd_is_auto_hibern8_supported(hba))
 		return;
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
-	if (hba->ahit == ahit)
-		goto out_unlock;
-	hba->ahit = ahit;
-	if (!pm_runtime_suspended(hba->dev))
-		ufshcd_writel(hba, hba->ahit, REG_AUTO_HIBERNATE_IDLE_TIMER);
-out_unlock:
+	if (hba->ahit != ahit) {
+		hba->ahit = ahit;
+		update = true;
+	}
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+	if (update && !pm_runtime_suspended(hba->dev)) {
+		pm_runtime_get_sync(hba->dev);
+		ufshcd_hold(hba, false);
+		ufshcd_auto_hibern8_enable(hba);
+		ufshcd_release(hba);
+		pm_runtime_put(hba->dev);
+	}
 }
 EXPORT_SYMBOL_GPL(ufshcd_auto_hibern8_update);
 
-- 
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