--- /dev/null
+From 2411fd94ceaa6e11326e95d6ebf876cbfed28d23 Mon Sep 17 00:00:00 2001
+From: Sherry Sun <sherry.sun@nxp.com>
+Date: Thu, 23 Feb 2023 17:39:41 +0800
+Subject: tty: serial: fsl_lpuart: skip waiting for transmission complete when UARTCTRL_SBK is asserted
+
+From: Sherry Sun <sherry.sun@nxp.com>
+
+commit 2411fd94ceaa6e11326e95d6ebf876cbfed28d23 upstream.
+
+According to LPUART RM, Transmission Complete Flag becomes 0 if queuing
+a break character by writing 1 to CTRL[SBK], so here need to skip
+waiting for transmission complete when UARTCTRL_SBK is asserted,
+otherwise the kernel may stuck here.
+And actually set_termios() adds transmission completion waiting to avoid
+data loss or data breakage when changing the baud rate, but we don't
+need to worry about this when queuing break characters.
+
+Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
+Cc: stable <stable@kernel.org>
+Link: https://lore.kernel.org/r/20230223093941.31790-1-sherry.sun@nxp.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/fsl_lpuart.c | 12 +++++++++---
+ 1 file changed, 9 insertions(+), 3 deletions(-)
+
+--- a/drivers/tty/serial/fsl_lpuart.c
++++ b/drivers/tty/serial/fsl_lpuart.c
+@@ -2002,9 +2002,15 @@ lpuart32_set_termios(struct uart_port *p
+ /* update the per-port timeout */
+ 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);
++ /*
++ * LPUART Transmission Complete Flag may never be set while queuing a break
++ * character, so skip waiting for transmission complete when UARTCTRL_SBK is
++ * asserted.
++ */
++ if (!(old_ctrl & UARTCTRL_SBK)) {
++ lpuart32_write(&sport->port, 0, UARTMODIR);
++ lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC);
++ }
+
+ /* disable transmit and receive */
+ lpuart32_write(&sport->port, old_ctrl & ~(UARTCTRL_TE | UARTCTRL_RE),