This is a note to let you know that I've just added the patch titled
serial: mvebu-uart: do not allow changing baudrate when uartclk is not available
to the 5.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-mvebu-uart-do-not-allow-changing-baudrate-whe.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8d8e814db04a01b3fde87d0b47df24b87bf005c1
Author: Pali Rohár <pali@xxxxxxxxxx>
Date: Fri Jun 25 00:49:01 2021 +0200
serial: mvebu-uart: do not allow changing baudrate when uartclk is not available
[ Upstream commit ecd6b010d81f97b06b2f64d2d4f50ebf5acddaa9 ]
Testing mvuart->clk for non-error is not enough as mvuart->clk may contain
valid clk pointer but when clk_prepare_enable(mvuart->clk) failed then
port->uartclk is zero.
When mvuart->clk is not available then port->uartclk is zero too.
Parent clock rate port->uartclk is needed to calculate UART clock divisor
and without it is not possible to change baudrate.
So fix test condition when it is possible to change baudrate.
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate")
Link: https://lore.kernel.org/r/20210624224909.6350-3-pali@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 908a4ac6b5a7..9638ae6aae79 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -445,12 +445,11 @@ static void mvebu_uart_shutdown(struct uart_port *port)
static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
{
- struct mvebu_uart *mvuart = to_mvuart(port);
unsigned int d_divisor, m_divisor;
u32 brdv, osamp;
- if (IS_ERR(mvuart->clk))
- return -PTR_ERR(mvuart->clk);
+ if (!port->uartclk)
+ return -EOPNOTSUPP;
/*
* The baudrate is derived from the UART clock thanks to two divisors:
