| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #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(unsigned 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(unsigned 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(unsigned int idx) |
| { |
| void *base = uart_platform_baseptr(idx); |
| if (!base) |
| return 0xff; |
| return uart8250_mem_rx_byte(base); |
| } |
| |
| void uart_tx_flush(unsigned int idx) |
| { |
| void *base = uart_platform_baseptr(idx); |
| if (!base) |
| return; |
| uart8250_mem_tx_flush(base); |
| } |
| |
| enum cb_err fill_lb_serial(struct lb_serial *serial) |
| { |
| serial->type = LB_SERIAL_TYPE_MEMORY_MAPPED; |
| serial->baseaddr = uart_platform_base(CONFIG_UART_FOR_CONSOLE); |
| if (!serial->baseaddr) |
| return CB_ERR; |
| 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(); |
| |
| return CB_SUCCESS; |
| } |