scsi: ufs: Fix possible unclocked access to auto hibern8 timer register

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

Link: https://lore.kernel.org/r/1583398391-14273-1-git-send-email-cang@codeaurora.org
Fixes: ba7af5ec5126 ("scsi: ufs: export ufshcd_auto_hibern8_update for vendor usage")
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index abd0e6b..2d70569 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -3884,18 +3884,25 @@ EXPORT_SYMBOL_GPL(ufshcd_uic_hibern8_exit);
 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);