FAILED: patch "[PATCH] serial: sprd: Add clearing break interrupt operation" failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From abeb2e9414d7e3a0d8417bc3b13d7172513ea8a0 Mon Sep 17 00:00:00 2001
From: Yonghan Ye <yonghan.ye@unisoc.com>
Date: Wed, 4 Dec 2019 20:00:07 +0800
Subject: [PATCH] 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 31df23502562..f60a59d9bf27 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);