diff options
Diffstat (limited to 'src/soc/nvidia/tegra124/uart.c')
| -rw-r--r-- | src/soc/nvidia/tegra124/uart.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/src/soc/nvidia/tegra124/uart.c b/src/soc/nvidia/tegra124/uart.c new file mode 100644 index 0000000000..d28cbb7016 --- /dev/null +++ b/src/soc/nvidia/tegra124/uart.c @@ -0,0 +1,137 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2009 Samsung Electronics + * + * 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; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <console/uart.h> +#include <arch/io.h> +#include <boot/coreboot_tables.h> +#include <console/console.h> /* for __console definition */ +#include <drivers/uart/uart8250reg.h> + + +struct tegra124_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. +} __attribute__ ((packed)); + +static void tegra124_uart_tx_flush(struct tegra124_uart *uart_ptr); +static int tegra124_uart_tst_byte(struct tegra124_uart *uart_ptr); + +static void tegra124_uart_init(struct tegra124_uart *uart_ptr) +{ + // Use a hardcoded divisor for now. + const unsigned divisor = 221; + const uint8_t line_config = UART8250_LCR_WLS_8; // 8n1 + + tegra124_uart_tx_flush(uart_ptr); + + // Disable interrupts. + write8(0, &uart_ptr->ier); + // Set line configuration, access divisor latches. + write8(UART8250_LCR_DLAB | line_config, &uart_ptr->lcr); + // Set the divisor. + write8(divisor & 0xff, &uart_ptr->dll); + write8((divisor >> 8) & 0xff, &uart_ptr->dlm); + // Hide the divisor latches. + write8(line_config, &uart_ptr->lcr); + // Enable FIFOs, and clear receive and transmit. + write8(UART8250_FCR_FIFO_EN | + UART8250_FCR_CLEAR_RCVR | + UART8250_FCR_CLEAR_XMIT, &uart_ptr->fcr); +} + +static unsigned char tegra124_uart_rx_byte(struct tegra124_uart *uart_ptr) +{ + if (!tegra124_uart_tst_byte(uart_ptr)) + return 0; + return read8(&uart_ptr->rbr); +} + +static void tegra124_uart_tx_byte(struct tegra124_uart *uart_ptr, unsigned char data) +{ + while (!(read8(&uart_ptr->lsr) & UART8250_LSR_THRE)); + write8(data, &uart_ptr->thr); +} + +static void tegra124_uart_tx_flush(struct tegra124_uart *uart_ptr) +{ + while (!(read8(&uart_ptr->lsr) & UART8250_LSR_TEMT)); +} + +static int tegra124_uart_tst_byte(struct tegra124_uart *uart_ptr) +{ + return (read8(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR; +} + +unsigned int uart_platform_base(int idx) +{ + //TODO:return the correct address based on which UART has been selected + return CONFIG_CONSOLE_SERIAL_UART_ADDRESS; +} + +void uart_init(int idx) +{ + struct tegra124_uart *uart_ptr = uart_platform_baseptr(idx); + tegra124_uart_init(uart_ptr); +} + +unsigned char uart_rx_byte(int idx) +{ + struct tegra124_uart *uart_ptr = uart_platform_baseptr(idx); + return tegra124_uart_rx_byte(uart_ptr); +} + +void uart_tx_byte(int idx, unsigned char data) +{ + struct tegra124_uart *uart_ptr = uart_platform_baseptr(idx); + tegra124_uart_tx_byte(uart_ptr, data); +} + +void uart_tx_flush(int idx) +{ + struct tegra124_uart *uart_ptr = uart_platform_baseptr(idx); + tegra124_uart_tx_flush(uart_ptr); +} + +#ifndef __PRE_RAM__ +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); + serial.baud = default_baudrate(); + lb_add_serial(&serial, data); + + lb_add_console(LB_TAG_CONSOLE_SERIAL8250MEM, data); +} +#endif |