serial: sprd: Add clearing break interrupt operation

commit abeb2e9414d7e3a0d8417bc3b13d7172513ea8a0 upstream.

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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Link: https://lore.kernel.org/r/925e51b73099c90158e080b8f5bed9b3b38c4548.1575460601.git.baolin.wang7@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 771d1119652315f7d60707d2de4f7160ff9275d1..494e2672ebd734cc53dbf17412d7070cff688d8a 100644 (file)
--- 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);