diff options
Diffstat (limited to 'src/soc/intel/apollolake/uart_early.c')
-rw-r--r-- | src/soc/intel/apollolake/uart_early.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/src/soc/intel/apollolake/uart_early.c b/src/soc/intel/apollolake/uart_early.c new file mode 100644 index 0000000000..d3b1d80fc3 --- /dev/null +++ b/src/soc/intel/apollolake/uart_early.c @@ -0,0 +1,61 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2015 Intel Corp. + * (Written by Alexandru Gagniuc <alexandrux.gagniuc@intel.com> for Intel Corp.) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <console/uart.h> +#include <device/pci.h> +#include <soc/gpio.h> +#include <soc/uart.h> +#include <soc/pci_devs.h> + +static void lpss_uart_write(uint16_t reg, uint32_t val) +{ + uintptr_t base = CONFIG_CONSOLE_UART_BASE_ADDRESS | reg; + write32((void *)base, val); +} + +void lpss_console_uart_init(void) +{ + uint32_t clk_sel; + device_t uart = _LPSS_PCI_DEV(UART, CONFIG_UART_FOR_CONSOLE & 3); + + if (CONFIG_UART_FOR_CONSOLE > 2) + return; + + /* Enable BAR0 for the UART -- this is where the 8250 registers hide */ + pci_write_config32(uart, PCI_BASE_ADDRESS_0, + CONFIG_CONSOLE_UART_BASE_ADDRESS); + + /* Enable memory access and bus master */ + pci_write_config32(uart, PCI_COMMAND, + PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER); + + /* Take UART out of reset */ + lpss_uart_write(UART_RESET, UART_RESET_UART_EN); + + /* These values get us a 1.836 MHz clock (ideally we want 1.843 MHz) */ + clk_sel = UART_CLK_DIV_N(0x7fff) | UART_CLK_DIV_M(0x025a); + /* Set M and N divisor inputs and enable clock */ + lpss_uart_write(UART_CLK, clk_sel | UART_CLK_UPDATE); + lpss_uart_write(UART_CLK, clk_sel | UART_CLK_EN); + +} + +uintptr_t uart_platform_base(int idx) +{ + return (CONFIG_CONSOLE_UART_BASE_ADDRESS); +} + +unsigned int uart_platform_refclk(void) +{ + /* That's within 0.5% of the actual value we've set earlier */ + return 115200 * 16; +} |