| /* |
| * This file is part of the coreboot project. |
| * |
| * Copyright 2018 MediaTek 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 <device/mmio.h> |
| #include <boot/coreboot_tables.h> |
| #include <console/uart.h> |
| #include <drivers/uart/uart8250reg.h> |
| #include <stdint.h> |
| |
| #include <soc/addressmap.h> |
| #include <soc/pll.h> |
| |
| struct mtk_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 efr; /* Enhanced feature register. */ |
| }; |
| uint32_t lcr; /* Line control register. */ |
| union { |
| uint32_t mcr; /* Modem control register. */ |
| uint32_t xn1; /* XON1 */ |
| }; |
| union { |
| uint32_t lsr; /* Line status register. */ |
| uint32_t xn2; /* XON2 */ |
| }; |
| union { |
| uint32_t msr; /* Modem status register. */ |
| uint32_t xf1; /* XOFF1 */ |
| }; |
| union { |
| uint32_t scr; /* Scratch register. */ |
| uint32_t xf2; /* XOFF2 */ |
| }; |
| uint32_t autobaud_en; /* Enable auto baudrate. */ |
| uint32_t highspeed; /* High speed UART. */ |
| } __packed; |
| |
| /* Peripheral Reset and Power Down registers */ |
| struct mtk_peri_globalcon { |
| uint32_t rst0; |
| uint32_t rst1; |
| uint32_t pdn0_set; |
| uint32_t pdn1_set; |
| uint32_t pdn0_clr; |
| uint32_t pdn1_clr; |
| uint32_t pdn0_sta; |
| uint32_t pdn1_sta; |
| uint32_t pdn_md1_set; |
| uint32_t pdn_md2_set; |
| uint32_t pdn_md1_clr; |
| uint32_t pdn_md2_clr; |
| uint32_t pdn_md1_sta; |
| uint32_t pdn_md2_sta; |
| uint32_t pdn_md_mask; |
| } __packed; |
| |
| static struct mtk_uart *const uart_ptr = (void *)UART0_BASE; |
| |
| static void mtk_uart_tx_flush(void); |
| static int mtk_uart_tst_byte(void); |
| |
| static void mtk_uart_init(void) |
| { |
| /* Use a hardcoded divisor for now. */ |
| const unsigned int uartclk = UART_HZ; |
| const unsigned int baudrate = get_uart_baudrate(); |
| const uint8_t line_config = UART8250_LCR_WLS_8; /* 8n1 */ |
| unsigned int highspeed, quot, divisor, remainder; |
| |
| if (baudrate <= 115200) { |
| highspeed = 0; |
| quot = 16; |
| } else { |
| highspeed = 2; |
| quot = 4; |
| } |
| |
| /* Set divisor DLL and DLH */ |
| divisor = uartclk / (quot * baudrate); |
| remainder = uartclk % (quot * baudrate); |
| |
| if (remainder >= (quot / 2) * baudrate) |
| divisor += 1; |
| |
| mtk_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 High speed UART register. */ |
| write8(&uart_ptr->highspeed, highspeed); |
| /* 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 mtk_uart_tx_byte(unsigned char data) |
| { |
| while (!(read8(&uart_ptr->lsr) & UART8250_LSR_THRE)) |
| ; |
| write8(&uart_ptr->thr, data); |
| } |
| |
| static void mtk_uart_tx_flush(void) |
| { |
| while (!(read8(&uart_ptr->lsr) & UART8250_LSR_TEMT)) |
| ; |
| } |
| |
| static unsigned char mtk_uart_rx_byte(void) |
| { |
| if (!mtk_uart_tst_byte()) |
| return 0; |
| return read8(&uart_ptr->rbr); |
| } |
| |
| static int mtk_uart_tst_byte(void) |
| { |
| return (read8(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR; |
| } |
| |
| void uart_init(int idx) |
| { |
| mtk_uart_init(); |
| } |
| |
| unsigned char uart_rx_byte(int idx) |
| { |
| return mtk_uart_rx_byte(); |
| } |
| |
| void uart_tx_byte(int idx, unsigned char data) |
| { |
| mtk_uart_tx_byte(data); |
| } |
| |
| void uart_tx_flush(int idx) |
| { |
| mtk_uart_tx_flush(); |
| } |
| |
| void uart_fill_lb(void *data) |
| { |
| struct lb_serial serial; |
| serial.type = LB_SERIAL_TYPE_MEMORY_MAPPED; |
| serial.baseaddr = UART0_BASE; |
| serial.baud = get_uart_baudrate(); |
| serial.regwidth = 4; |
| serial.input_hertz = UART_HZ; |
| serial.uart_pci_addr = CONFIG_UART_PCI_ADDR; |
| lb_add_serial(&serial, data); |
| |
| lb_add_console(LB_TAG_CONSOLE_SERIAL8250MEM, data); |
| } |