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Diffstat (limited to 'src/soc/marvell/armada38x/uart.c')
| -rw-r--r-- | src/soc/marvell/armada38x/uart.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/soc/marvell/armada38x/uart.c b/src/soc/marvell/armada38x/uart.c new file mode 100644 index 0000000000..e535aebf67 --- /dev/null +++ b/src/soc/marvell/armada38x/uart.c @@ -0,0 +1,151 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2015 Google Inc. + * + * 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. + */ + +#include <arch/io.h> +#include <console/uart.h> +#include <console/console.h> +#include <drivers/uart/uart8250reg.h> +#include <boot/coreboot_tables.h> +#include <stdint.h> +#include <assert.h> +#include <soc/common.h> + +struct armada38x_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 armada38x_uart_tx_flush(struct armada38x_uart *uart_ptr); +static int armada38x_uart_tst_byte(struct armada38x_uart *uart_ptr); + +static void armada38x_uart_init(struct armada38x_uart *uart_ptr) +{ + const uint8_t line_config = UART8250_LCR_WLS_8; + uint16_t divisor = (u16) uart_baudrate_divisor(default_baudrate(), + uart_platform_refclk(), 16); + + armada38x_uart_tx_flush(uart_ptr); + // Disable interrupts. + write8(&uart_ptr->ier, 0); + // Enable access to divisor latches. + write8(&uart_ptr->lcr, UART8250_LCR_DLAB); + // Set the divisor. + write8(&uart_ptr->dll, divisor & 0xff); + write8(&uart_ptr->dlm, (divisor >> 8) & 0xff); + // Hide divisor latches and program line config. + 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 armada38x_uart_tx_byte(struct armada38x_uart *uart_ptr, + unsigned char data) +{ + while (!(read8(&uart_ptr->lsr) & UART8250_LSR_THRE)) + ; + write8(&uart_ptr->thr, data); +} + +static void armada38x_uart_tx_flush(struct armada38x_uart *uart_ptr) +{ + while (!(read8(&uart_ptr->lsr) & UART8250_LSR_TEMT)) + ; +} + +static unsigned char armada38x_uart_rx_byte(struct armada38x_uart *uart_ptr) +{ + if (!armada38x_uart_tst_byte(uart_ptr)) + return 0; + return read8(&uart_ptr->rbr); +} + +static int armada38x_uart_tst_byte(struct armada38x_uart *uart_ptr) +{ + return (read8(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR; +} + +unsigned int uart_platform_refclk(void) +{ + return MV_BOARD_TCLK_250MHZ; +} + +uintptr_t uart_platform_base(int idx) +{ + /* Default to UART 0 */ + unsigned int base = CONFIG_CONSOLE_SERIAL_UART_ADDRESS; + + assert((idx >= 0) && (idx < 2)); + base += idx * 0x100; + return base; +} + +void uart_init(int idx) +{ + struct armada38x_uart *uart_ptr = uart_platform_baseptr(idx); + + armada38x_uart_init(uart_ptr); +} + +void uart_tx_byte(int idx, unsigned char data) +{ + struct armada38x_uart *uart_ptr = uart_platform_baseptr(idx); + + armada38x_uart_tx_byte(uart_ptr, data); +} + +void uart_tx_flush(int idx) +{ + struct armada38x_uart *uart_ptr = uart_platform_baseptr(idx); + + armada38x_uart_tx_flush(uart_ptr); +} + +unsigned char uart_rx_byte(int idx) +{ + struct armada38x_uart *uart_ptr = uart_platform_baseptr(idx); + + return armada38x_uart_rx_byte(uart_ptr); +} + +#if ENV_RAMSTAGE +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(); + serial.regwidth = 1; + lb_add_serial(&serial, data); + + lb_add_console(LB_TAG_CONSOLE_SERIAL8250MEM, data); +} +#endif |