driver/uart: Introduce a way for mainboard to override the baudrate

The rationale is to allow the mainboard to override the default
baudrate for instance by sampling GPIOs at boot.

A new configuration option is available for mainboards to select
this behaviour. It will then have to define the function
get_uart_baudrate to return the computed baudrate.

Change-Id: I970ee788bf90b9e1a8c6ccdc5eee8029d9af0ecc
Signed-off-by: Julien Viard de Galbert <jviarddegalbert@online.net>
Reviewed-on: https://review.coreboot.org/23713
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/soc/mediatek/mt8173/uart.c b/src/soc/mediatek/mt8173/uart.c
index 36a279fa65..93625c4bfb 100644
--- a/src/soc/mediatek/mt8173/uart.c
+++ b/src/soc/mediatek/mt8173/uart.c
@@ -87,7 +87,7 @@ static void mtk_uart_init(void)
 {
 	/* Use a hardcoded divisor for now. */
 	const unsigned uartclk = 26 * MHz;
-	const unsigned baudrate = CONFIG_TTYS0_BAUD;
+	const unsigned baudrate = get_uart_baudrate();
 	const uint8_t line_config = UART8250_LCR_WLS_8;	/* 8n1 */
 	unsigned highspeed, quot, divisor, remainder;
 
@@ -177,7 +177,7 @@ void uart_fill_lb(void *data)
 	struct lb_serial serial;
 	serial.type = LB_SERIAL_TYPE_MEMORY_MAPPED;
 	serial.baseaddr = UART0_BASE;
-	serial.baud = CONFIG_TTYS0_BAUD;
+	serial.baud = get_uart_baudrate();
 	serial.regwidth = 4;
 	lb_add_serial(&serial, data);