From: Michal Simek michal.simek@xilinx.com

commit 814453adea7d081ad8917aa0f32d6a14165a3563 upstream.

On DT based platforms when current-speed property is present baudrate is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16 value. Drivers like uartps/ns16550 contain logic when baudrate and uartclk is used for baudrate calculation.

The patch is reading optional clock-frequency property to replace bogus BASE_BAUD * 16 calculation to have proper baudrate calculation.

[-stable comment: commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") has changed 8250_early.c behavior which now tries to setup UART speed. Ignoring clock-frequency results in wrong value of calculated divisor & malformed early console output.]

Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Signed-off-by: Michal Simek michal.simek@xilinx.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [rmilecki: add -stable comment and Fixes tag] Signed-off-by: Rafał Miłecki rafal@milecki.pl --- drivers/tty/serial/earlycon.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index ac667b47f199..05ba1875bb3e 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -289,6 +289,10 @@ int __init of_setup_earlycon(const struct earlycon_id *match, if (val) early_console_dev.baud = be32_to_cpu(*val);

+ val = of_get_flat_dt_prop(node, "clock-frequency", NULL); + if (val) + port->uartclk = be32_to_cpu(*val); + if (options) { early_console_dev.baud = simple_strtoul(options, NULL, 0); strlcpy(early_console_dev.options, options,