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From:   Baolin Wang <baolin.wang7@gmail.com>
To:     gregkh@linuxfoundation.org, jslaby@suse.com
Cc:     orsonzhai@gmail.com, zhang.lyra@gmail.com, yonghan.ye@unisoc.com,
        lanqing.liu@unisoc.com, baolin.wang7@gmail.com,
        linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] serial: sprd: Add clearing break interrupt operation
Date:   Wed,  4 Dec 2019 20:00:07 +0800
Message-Id: <925e51b73099c90158e080b8f5bed9b3b38c4548.1575460601.git.baolin.wang7@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Yonghan Ye <yonghan.ye@unisoc.com>

A break interrupt will be generated if the RX line was pulled low, which
means some abnomal behaviors occurred of the UART. In this case, we still
need to clear this break interrupt status, otherwise it will cause irq
storm to crash the whole system.

Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support")
Signed-off-by: Yonghan Ye <yonghan.ye@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
 drivers/tty/serial/sprd_serial.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 31df235..f60a59d 100644
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -679,6 +679,9 @@ static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
 	if (ims & SPRD_IMSR_TIMEOUT)
 		serial_out(port, SPRD_ICLR, SPRD_ICLR_TIMEOUT);
 
+	if (ims & SPRD_IMSR_BREAK_DETECT)
+		serial_out(port, SPRD_ICLR, SPRD_IMSR_BREAK_DETECT);
+
 	if (ims & (SPRD_IMSR_RX_FIFO_FULL | SPRD_IMSR_BREAK_DETECT |
 		   SPRD_IMSR_TIMEOUT))
 		sprd_rx(port);
-- 
1.7.9.5