| /* 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 <drivers/uart/uart8250reg.h> |
| #include <stdint.h> |
| |
| struct tegra210_uart { |
| union { |
| uint32_t thr; // Transmit holding register. |
| uint32_t rbr; // Receive buffer register. |
| uint32_t dll; // Divisor latch lsb. |
| }; |
| union { |
| uint32_t ier; // Interrupt enable register. |
| uint32_t dlm; // Divisor latch msb. |
| }; |
| union { |
| uint32_t iir; // Interrupt identification register. |
| uint32_t fcr; // FIFO control register. |
| }; |
| uint32_t lcr; // Line control register. |
| uint32_t mcr; // Modem control register. |
| uint32_t lsr; // Line status register. |
| uint32_t msr; // Modem status register. |
| } __packed; |
| |
| |
| static struct tegra210_uart * const uart_ptr = |
| (void *)CONFIG_CONSOLE_SERIAL_TEGRA210_UART_ADDRESS; |
| |
| static void tegra210_uart_tx_flush(void); |
| static int tegra210_uart_tst_byte(void); |
| |
| static void tegra210_uart_init(void) |
| { |
| // Use a hardcoded divisor for now. |
| const unsigned int divisor = 221; |
| const uint8_t line_config = UART8250_LCR_WLS_8; // 8n1 |
| |
| tegra210_uart_tx_flush(); |
| |
| // Disable interrupts. |
| write8(&uart_ptr->ier, 0); |
| // Force DTR and RTS to high. |
| write8(&uart_ptr->mcr, UART8250_MCR_DTR | UART8250_MCR_RTS); |
| // Set line configuration, access divisor latches. |
| write8(&uart_ptr->lcr, UART8250_LCR_DLAB | line_config); |
| // Set the divisor. |
| write8(&uart_ptr->dll, divisor & 0xff); |
| write8(&uart_ptr->dlm, (divisor >> 8) & 0xff); |
| // Hide the divisor latches. |
| write8(&uart_ptr->lcr, line_config); |
| // Enable FIFOs, and clear receive and transmit. |
| write8(&uart_ptr->fcr, |
| UART8250_FCR_FIFO_EN | |
| UART8250_FCR_CLEAR_RCVR | |
| UART8250_FCR_CLEAR_XMIT); |
| } |
| |
| static void tegra210_uart_tx_byte(unsigned char data) |
| { |
| while (!(read8(&uart_ptr->lsr) & UART8250_LSR_THRE)); |
| write8(&uart_ptr->thr, data); |
| } |
| |
| static void tegra210_uart_tx_flush(void) |
| { |
| while (!(read8(&uart_ptr->lsr) & UART8250_LSR_TEMT)); |
| } |
| |
| static unsigned char tegra210_uart_rx_byte(void) |
| { |
| if (!tegra210_uart_tst_byte()) |
| return 0; |
| return read8(&uart_ptr->rbr); |
| } |
| |
| static int tegra210_uart_tst_byte(void) |
| { |
| return (read8(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR; |
| } |
| |
| void uart_init(int idx) |
| { |
| tegra210_uart_init(); |
| } |
| |
| void uart_tx_byte(int idx, unsigned char data) |
| { |
| tegra210_uart_tx_byte(data); |
| } |
| |
| void uart_tx_flush(int idx) |
| { |
| tegra210_uart_tx_flush(); |
| } |
| |
| unsigned char uart_rx_byte(int idx) |
| { |
| return tegra210_uart_rx_byte(); |
| } |
| |
| void uart_fill_lb(void *data) |
| { |
| struct lb_serial serial; |
| serial.type = LB_SERIAL_TYPE_MEMORY_MAPPED; |
| serial.baseaddr = CONFIG_CONSOLE_SERIAL_TEGRA210_UART_ADDRESS; |
| serial.baud = get_uart_baudrate(); |
| serial.regwidth = 4; |
| 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); |
| } |