| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #include <arch/io.h> |
| #include <console/system76_ec.h> |
| #include <timer.h> |
| |
| // This is the command region for Librem EC firmware. It must be |
| // enabled for LPC in the mainboard. |
| #define LIBREM_EC_BASE 0x0E00 |
| #define LIBREM_EC_SIZE 256 |
| |
| #define REG_CMD 0 |
| #define REG_RESULT 1 |
| |
| // When command register is 0, command is complete |
| #define CMD_FINISHED 0 |
| |
| // Print command. Registers are unique for each command |
| #define CMD_PRINT 4 |
| #define CMD_PRINT_REG_FLAGS 2 |
| #define CMD_PRINT_REG_LEN 3 |
| #define CMD_PRINT_REG_DATA 4 |
| |
| static inline uint8_t system76_ec_read(uint8_t addr) |
| { |
| return inb(LIBREM_EC_BASE + (uint16_t)addr); |
| } |
| |
| static inline void system76_ec_write(uint8_t addr, uint8_t data) |
| { |
| outb(data, LIBREM_EC_BASE + (uint16_t)addr); |
| } |
| |
| void system76_ec_init(void) |
| { |
| // Clear entire command region |
| for (int i = 0; i < LIBREM_EC_SIZE; i++) |
| system76_ec_write((uint8_t)i, 0); |
| } |
| |
| void system76_ec_flush(void) |
| { |
| system76_ec_write(REG_CMD, CMD_PRINT); |
| |
| // Wait for command completion, for up to 10 milliseconds, with a |
| // test period of 1 microsecond |
| wait_us(10000, system76_ec_read(REG_CMD) == CMD_FINISHED); |
| |
| system76_ec_write(CMD_PRINT_REG_LEN, 0); |
| } |
| |
| void system76_ec_print(uint8_t byte) |
| { |
| uint8_t len = system76_ec_read(CMD_PRINT_REG_LEN); |
| system76_ec_write(CMD_PRINT_REG_DATA + len, byte); |
| system76_ec_write(CMD_PRINT_REG_LEN, len + 1); |
| |
| // If we hit the end of the buffer, or were given a newline, flush |
| if (byte == '\n' || len >= (LIBREM_EC_SIZE - CMD_PRINT_REG_DATA)) |
| system76_ec_flush(); |
| } |