From: Andrey Smirnov <andrew.smirnov@gmail.com>
Date: Fri, 4 Oct 2019 14:55:37 -0700
Subject: tty: serial: fsl_lpuart: Fix lpuart_flush_buffer()

Git-commit: 5df884d4b8a5bf2ec5e0b92394e40112d0a0a520
Patch-mainline: v5.4-rc3
References: jsc#SLE-12251

Fix incorrect read-modify-write sequence in lpuart_flush_buffer() that
was reading from UARTPFIFO and writing to UARTCFIFO instead of
operating solely on the latter.

Fixes: 9bc19af9dacb ("tty: serial: fsl_lpuart: Flush HW FIFOs in .flush_buffer")
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reported-by: Vivien Didelot <vivien.didelot@gmail.com>
Tested-by: Vivien Didelot <vivien.didelot@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Jiri Slaby <jslaby@suse.com>
Link: https://lore.kernel.org/r/20191004215537.5308-1-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/tty/serial/fsl_lpuart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 3e17bb8a0b16..537896c4d887 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -548,7 +548,7 @@ static void lpuart_flush_buffer(struct uart_port *port)
 		val |= UARTFIFO_TXFLUSH | UARTFIFO_RXFLUSH;
 		lpuart32_write(&sport->port, val, UARTFIFO);
 	} else {
-		val = readb(sport->port.membase + UARTPFIFO);
+		val = readb(sport->port.membase + UARTCFIFO);
 		val |= UARTCFIFO_TXFLUSH | UARTCFIFO_RXFLUSH;
 		writeb(val, sport->port.membase + UARTCFIFO);
 	}
-- 
2.26.2