serial: sprd: Add clearing break interrupt operation

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 31df23502562383ddfe2cbb0e0d7d98865ed5d21..f60a59d9bf271074dfde293a695ea0d8558e91c9 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);