Leroy P Leahy (leroy.p.leahy@intel.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14611
-gerrit
commit 51f39261b7228eecff4c59bd3390c5df23a74711 Author: Lee Leahy leroy.p.leahy@intel.com Date: Wed May 4 13:13:20 2016 -0700
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 leroy.p.leahy@intel.com --- src/drivers/uart/Kconfig | 7 +++++++ src/drivers/uart/uart8250io.c | 5 ++--- src/drivers/uart/uart8250mem.c | 3 ++- src/drivers/uart/util.c | 7 +++++++ src/include/console/uart.h | 4 ++++ 5 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/src/drivers/uart/Kconfig b/src/drivers/uart/Kconfig index dbdfcb0..aaf6e0e 100644 --- a/src/drivers/uart/Kconfig +++ b/src/drivers/uart/Kconfig @@ -13,6 +13,13 @@ config DRIVERS_UART_8250IO config NO_UART_ON_SUPERIO def_bool n
+config UART_OVERRIDE_INPUT_CLOCK_DIVIDER + boolean + default n + help + Set to "y" when the platform overrides the uart_input_clock_divider + routine. + config DRIVERS_UART_8250MEM bool default n diff --git a/src/drivers/uart/uart8250io.c b/src/drivers/uart/uart8250io.c index 9fdf8a1..d85e497 100644 --- a/src/drivers/uart/uart8250io.c +++ b/src/drivers/uart/uart8250io.c @@ -30,8 +30,7 @@ /* Nominal values only, good for the range of choices Kconfig offers for * set of standard baudrates. */ -#define BAUDRATE_REFCLK (115200) -#define BAUDRATE_OVERSAMPLE (1) +#define BAUDRATE_REFCLK (115200 * 16)
/* Expected character delay at 1200bps is 9ms for a working UART * and no flow-control. Assume UART as stuck if shift register @@ -112,7 +111,7 @@ void uart_init(int idx) { unsigned int div; div = uart_baudrate_divisor(default_baudrate(), BAUDRATE_REFCLK, - BAUDRATE_OVERSAMPLE); + uart_input_clock_divider()); uart8250_init(uart_platform_base(idx), div); }
diff --git a/src/drivers/uart/uart8250mem.c b/src/drivers/uart/uart8250mem.c index f7e0cdf..9dac2f7 100644 --- a/src/drivers/uart/uart8250mem.c +++ b/src/drivers/uart/uart8250mem.c @@ -117,7 +117,8 @@ void uart_init(int idx) return;
unsigned int div; - div = uart_baudrate_divisor(default_baudrate(), uart_platform_refclk(), 16); + div = uart_baudrate_divisor(default_baudrate(), + uart_platform_refclk(), uart_input_clock_divider()); uart8250_mem_init(base, div); }
diff --git a/src/drivers/uart/util.c b/src/drivers/uart/util.c index 4121f60..53c32ed 100644 --- a/src/drivers/uart/util.c +++ b/src/drivers/uart/util.c @@ -42,3 +42,10 @@ unsigned int uart_baudrate_divisor(unsigned int baudrate, { return (1 + (2 * refclk) / (baudrate * oversample)) / 2; } + +# if !IS_ENABLED(CONFIG_UART_OVERRIDE_INPUT_CLOCK_DIVIDER) +unsigned int uart_input_clock_divider(void) +{ + return 16; +} +#endif diff --git a/src/include/console/uart.h b/src/include/console/uart.h index 8458086..a3d650b 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);
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Leroy P Leahy