From 148762110c8a00c88b8e0326ec69dc7392bf3739 Mon Sep 17 00:00:00 2001 From: Lee Leahy Date: Wed, 4 May 2016 13:13:20 -0700 Subject: drivers/uart: Enable override for input clock divider Allow the platform to override the input clock divider by adding the uart_input_clock_divider routine. This routine combines the baud-rate oversample divider with any other input clock divider. The default routine returns 16 which is the standard baud-rate oversampling value. A platform may override this default "weak" routine by providing a new routine and selecting UART_OVERRIDE_INPUT_CLOCK_DIVIDER. This works around ROMCC not supporting weak routines. Testing on Galileo: * Edit the src/mainboard/intel/galileo/Makefile.inc file: * Add "select ADD_FSP_PDAT_FILE" * Add "select ADD_FSP_RAW_BIN" * Add "select ADD_RMU_FILE" * Place the FSP.bin file in the location specified by CONFIG_FSP_FILE * Place the pdat.bin files in the location specified by CONFIG_FSP_PDAT_FILE * Place the rmu.bin file in the location specified by CONFIG_RMU_FILE * Build EDK2 CorebootPayloadPkg/CorebootPayloadPkgIa32.dsc to generate UEFIPAYLOAD.fd * Testing is successful when CorebootPayloadPkg is able to properly initialize the serial port without using built-in values. Change-Id: Ieb6453b045d84702b8f730988d0fed9f253f63e2 Signed-off-by: Lee Leahy Reviewed-on: https://review.coreboot.org/14611 Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth --- src/include/console/uart.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'src/include') diff --git a/src/include/console/uart.h b/src/include/console/uart.h index 8458086d49..a3d650b500 100644 --- a/src/include/console/uart.h +++ b/src/include/console/uart.h @@ -35,6 +35,10 @@ unsigned int default_baudrate(void); unsigned int uart_baudrate_divisor(unsigned int baudrate, unsigned int refclk, unsigned int oversample); +/* Returns the oversample divisor multiplied by any other divisors that act + * on the input clock + */ +unsigned int uart_input_clock_divider(void); void uart_init(int idx); void uart_tx_byte(int idx, unsigned char data); -- cgit v1.2.3