tty: serial: fsl_lpuart: Fix lpuart_flush_buffer()

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>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 3e17bb8a0b16eea373f5748dde9551175b71d5f5..537896c4d887e278e2ea48d8fcd9abe224ab4944 100644 (file)
--- 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);
        }