[PATCH v1] scsi: ufs: add wmb after clear interrupt status

[peter.wang at mediatek.com]

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

Write IS(0x20) to clear interrupts should be done before
read UTRLDBR(0x58) or UTRLCNR(0x64).
If optimize lead to read TRLDBR(0x58) or UTRLCNR(0x64) before
Write IS(0x20), the final complete task may miss.

Signed-off-by: Peter Wang <peter.wang at mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3841ab49f556..3318b3b6c916 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6492,6 +6492,10 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)
 		enabled_intr_status =
 			intr_status & ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
 		ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
+
+		/* Make sure interrupt status are clear before service */
+		wmb();
+
 		if (enabled_intr_status)
 			retval |= ufshcd_sl_intr(hba, enabled_intr_status);
 
-- 
2.18.0