The patch below does not apply to the 4.14-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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From d5a2e0834364377a5d5a2fff1890a0b3f0bafd1f Mon Sep 17 00:00:00 2001
From: Sherry Sun <sherry.sun@xxxxxxx>
Date: Sun, 21 Aug 2022 18:15:27 +0800
Subject: [PATCH] tty: serial: lpuart: disable flow control while waiting for
the transmit engine to complete
When the user initializes the uart port, and waits for the transmit
engine to complete in lpuart32_set_termios(), if the UART TX fifo has
dirty data and the UARTMODIR enable the flow control, the TX fifo may
never be empty. So here we should disable the flow control first to make
sure the transmit engin can complete.
Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
Link: https://lore.kernel.org/r/20220821101527.10066-1-sherry.sun@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index e9ba0f0bd441..b20f6f2fa51c 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -2191,6 +2191,7 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
uart_update_timeout(port, termios->c_cflag, baud);
/* wait transmit engin complete */
+ lpuart32_write(&sport->port, 0, UARTMODIR);
lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC);
/* disable transmit and receive */
