diff options
| author | Philipp Hug <philipp@hug.cx> | 2018-07-07 21:34:31 +0200 |
|---|---|---|
| committer | Ronald G. Minnich <rminnich@gmail.com> | 2018-09-13 15:32:53 +0000 |
| commit | 7524400242be26610df143b5d1d781f875239c45 (patch) | |
| tree | a8055581b7f492e2bddbb8937f7649c043db33bd /src | |
| parent | 3e51d530645059093e6dd27c4bbfafb8a216cd41 (diff) | |
| download | coreboot-7524400242be26610df143b5d1d781f875239c45.tar.xz | |
uart/sifive: make divisor configurable
The SiFive UART on the HiFive Unleashed uses the tlclk as input clock
which runs at coreclk / 2.
The input frequency is configured in the board code depending on the
current stage. (bootblock + romstage run at 33.33Mhz, ramstage at 1Ghz)
Change-Id: Iaf66723dba3d308f809fde5b05dfc3e43f43bd42
Signed-off-by: Philipp Hug <philipp@hug.cx>
Reviewed-on: https://review.coreboot.org/27440
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Diffstat (limited to 'src')
| -rw-r--r-- | src/drivers/uart/sifive.c | 15 | ||||
| -rw-r--r-- | src/soc/sifive/fu540/Kconfig | 2 | ||||
| -rw-r--r-- | src/soc/sifive/fu540/uart.c | 8 |
3 files changed, 20 insertions, 5 deletions
diff --git a/src/drivers/uart/sifive.c b/src/drivers/uart/sifive.c index dd47cafcf1..ce8ead0d05 100644 --- a/src/drivers/uart/sifive.c +++ b/src/drivers/uart/sifive.c @@ -46,11 +46,10 @@ struct sifive_uart_registers { #define IP_TXWM BIT(0) #define IP_RXWM BIT(1) -void uart_init(int idx) +static void sifive_uart_init(struct sifive_uart_registers *regs, int div) { - struct sifive_uart_registers *regs = uart_platform_baseptr(idx); - - /* TODO: Configure the divisor */ + /* Configure the divisor */ + write32(®s->div, div); /* Enable transmission, one stop bit, transmit watermark at 1 */ write32(®s->txctrl, TXCTRL_TXEN|TXCTRL_NSTOP(1)|TXCTRL_TXCNT(1)); @@ -59,6 +58,14 @@ void uart_init(int idx) write32(®s->rxctrl, RXCTRL_RXEN|RXCTRL_RXCNT(0)); } +void uart_init(int idx) +{ + unsigned int div; + div = uart_baudrate_divisor(get_uart_baudrate(), + uart_platform_refclk(), uart_input_clock_divider()); + sifive_uart_init(uart_platform_baseptr(idx), div); +} + static bool uart_can_tx(struct sifive_uart_registers *regs) { return !(read32(®s->txdata) & TXDATA_FULL); diff --git a/src/soc/sifive/fu540/Kconfig b/src/soc/sifive/fu540/Kconfig index c438a10162..457d16bb4e 100644 --- a/src/soc/sifive/fu540/Kconfig +++ b/src/soc/sifive/fu540/Kconfig @@ -20,7 +20,7 @@ config SOC_SIFIVE_FU540 select ARCH_RAMSTAGE_RISCV select BOOTBLOCK_CONSOLE select DRIVERS_UART_SIFIVE - + select UART_OVERRIDE_REFCLK if SOC_SIFIVE_FU540 config RISCV_ARCH diff --git a/src/soc/sifive/fu540/uart.c b/src/soc/sifive/fu540/uart.c index 940dc97856..c53f42d9d8 100644 --- a/src/soc/sifive/fu540/uart.c +++ b/src/soc/sifive/fu540/uart.c @@ -23,3 +23,11 @@ uintptr_t uart_platform_base(int idx) else return 0; } + +unsigned int uart_platform_refclk(void) +{ + /* + * The SiFive UART uses tlclk, which is coreclk/2 as input + */ + return 33330000 / 2; +} |