/* SPDX-License-Identifier: GPL-2.0-only */ /* This file is part of the coreboot project. */ #include <device/mmio.h> #include <boot/coreboot_tables.h> #include <console/uart.h> #include <device/device.h> #include <delay.h> #include <stdint.h> #include "uart8250reg.h" /* Should support 8250, 16450, 16550, 16550A type UARTs */ /* Expected character delay at 1200bps is 9ms for a working UART * and no flow-control. Assume UART as stuck if shift register * or FIFO takes more than 50ms per character to appear empty. */ #define SINGLE_CHAR_TIMEOUT (50 * 1000) #define FIFO_TIMEOUT (16 * SINGLE_CHAR_TIMEOUT) #if CONFIG(DRIVERS_UART_8250MEM_32) static uint8_t uart8250_read(void *base, uint8_t reg) { return read32(base + 4 * reg) & 0xff; } static void uart8250_write(void *base, uint8_t reg, uint8_t data) { write32(base + 4 * reg, data); } #else static uint8_t uart8250_read(void *base, uint8_t reg) { return read8(base + reg); } static void uart8250_write(void *base, uint8_t reg, uint8_t data) { write8(base + reg, data); } #endif static int uart8250_mem_can_tx_byte(void *base) { return uart8250_read(base, UART8250_LSR) & UART8250_LSR_THRE; } static void uart8250_mem_tx_byte(void *base, unsigned char data) { unsigned long int i = SINGLE_CHAR_TIMEOUT; while (i-- && !uart8250_mem_can_tx_byte(base)) udelay(1); uart8250_write(base, UART8250_TBR, data); } static void uart8250_mem_tx_flush(void *base) { unsigned long int i = FIFO_TIMEOUT; while (i-- && !(uart8250_read(base, UART8250_LSR) & UART8250_LSR_TEMT)) udelay(1); } static int uart8250_mem_can_rx_byte(void *base) { return uart8250_read(base, UART8250_LSR) & UART8250_LSR_DR; } static unsigned char uart8250_mem_rx_byte(void *base) { unsigned long int i = SINGLE_CHAR_TIMEOUT; while (i && !uart8250_mem_can_rx_byte(base)) { udelay(1); i--; } if (i) return uart8250_read(base, UART8250_RBR); else return 0x0; } static void uart8250_mem_init(void *base, unsigned int divisor) { /* Disable interrupts */ uart8250_write(base, UART8250_IER, 0x0); /* Enable FIFOs */ uart8250_write(base, UART8250_FCR, UART8250_FCR_FIFO_EN); /* Assert DTR and RTS so the other end is happy */ uart8250_write(base, UART8250_MCR, UART8250_MCR_DTR | UART8250_MCR_RTS); /* DLAB on */ uart8250_write(base, UART8250_LCR, UART8250_LCR_DLAB | CONFIG_TTYS0_LCS); uart8250_write(base, UART8250_DLL, divisor & 0xFF); uart8250_write(base, UART8250_DLM, (divisor >> 8) & 0xFF); /* Set to 3 for 8N1 */ uart8250_write(base, UART8250_LCR, CONFIG_TTYS0_LCS); } void uart_init(int idx) { void *base = uart_platform_baseptr(idx); if (!base) return; unsigned int div; div = uart_baudrate_divisor(get_uart_baudrate(), uart_platform_refclk(), uart_input_clock_divider()); uart8250_mem_init(base, div); } void uart_tx_byte(int idx, unsigned char data) { void *base = uart_platform_baseptr(idx); if (!base) return; uart8250_mem_tx_byte(base, data); } unsigned char uart_rx_byte(int idx) { void *base = uart_platform_baseptr(idx); if (!base) return 0xff; return uart8250_mem_rx_byte(base); } void uart_tx_flush(int idx) { void *base = uart_platform_baseptr(idx); if (!base) return; uart8250_mem_tx_flush(base); } void uart_fill_lb(void *data) { struct lb_serial serial; serial.type = LB_SERIAL_TYPE_MEMORY_MAPPED; serial.baseaddr = uart_platform_base(CONFIG_UART_FOR_CONSOLE); if (!serial.baseaddr) return; serial.baud = get_uart_baudrate(); if (CONFIG(DRIVERS_UART_8250MEM_32)) serial.regwidth = sizeof(uint32_t); else serial.regwidth = sizeof(uint8_t); serial.input_hertz = uart_platform_refclk(); serial.uart_pci_addr = CONFIG_UART_PCI_ADDR; lb_add_serial(&serial, data); lb_add_console(LB_TAG_CONSOLE_SERIAL8250MEM, data); }