1 // SPDX-License-Identifier: BSD-2-Clause 2 /* 3 * Copyright (c) 2015, Linaro Limited 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright notice, 10 * this list of conditions and the following disclaimer. 11 * 12 * 2. Redistributions in binary form must reproduce the above copyright notice, 13 * this list of conditions and the following disclaimer in the documentation 14 * and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <compiler.h> 30 #include <console.h> 31 #include <drivers/serial8250_uart.h> 32 #include <io.h> 33 #include <keep.h> 34 #include <util.h> 35 36 /* uart register defines */ 37 #define UART_RHR 0x0 38 #define UART_THR 0x0 39 #define UART_IER 0x4 40 #define UART_ISR 0x8 41 #define UART_FCR 0x8 42 #define UART_LCR 0xc 43 #define UART_MCR 0x10 44 #define UART_LSR 0x14 45 #define UART_MSR 0x18 46 #define UART_SPR 0x1c 47 48 /* uart status register bits */ 49 #define LSR_TEMT 0x40 /* Transmitter empty */ 50 #define LSR_THRE 0x20 /* Transmit-hold-register empty */ 51 #define LSR_EMPTY (LSR_TEMT | LSR_THRE) 52 #define LSR_DR 0x01 /* DATA Ready */ 53 54 static vaddr_t chip_to_base(struct serial_chip *chip) 55 { 56 struct serial8250_uart_data *pd = 57 container_of(chip, struct serial8250_uart_data, chip); 58 59 return io_pa_or_va(&pd->base); 60 } 61 62 static void serial8250_uart_flush(struct serial_chip *chip) 63 { 64 vaddr_t base = chip_to_base(chip); 65 66 while (1) { 67 uint32_t state = read32(base + UART_LSR); 68 69 /* Wait until transmit FIFO is empty */ 70 if ((state & LSR_EMPTY) == LSR_EMPTY) 71 break; 72 } 73 } 74 75 static bool serial8250_uart_have_rx_data(struct serial_chip *chip) 76 { 77 vaddr_t base = chip_to_base(chip); 78 79 return (read32(base + UART_LSR) & LSR_DR); 80 } 81 82 static int serial8250_uart_getchar(struct serial_chip *chip) 83 { 84 vaddr_t base = chip_to_base(chip); 85 86 while (!serial8250_uart_have_rx_data(chip)) { 87 /* Transmit FIFO is empty, waiting again */ 88 ; 89 } 90 return read32(base + UART_RHR) & 0xff; 91 } 92 93 static void serial8250_uart_putc(struct serial_chip *chip, int ch) 94 { 95 vaddr_t base = chip_to_base(chip); 96 97 serial8250_uart_flush(chip); 98 99 /* Write out character to transmit FIFO */ 100 write32(ch, base + UART_THR); 101 } 102 103 static const struct serial_ops serial8250_uart_ops = { 104 .flush = serial8250_uart_flush, 105 .getchar = serial8250_uart_getchar, 106 .have_rx_data = serial8250_uart_have_rx_data, 107 .putc = serial8250_uart_putc, 108 }; 109 KEEP_PAGER(serial8250_uart_ops); 110 111 void serial8250_uart_init(struct serial8250_uart_data *pd, paddr_t base, 112 uint32_t __unused uart_clk, 113 uint32_t __unused baud_rate) 114 115 { 116 pd->base.pa = base; 117 pd->chip.ops = &serial8250_uart_ops; 118 119 /* 120 * do nothing, debug uart(uart0) share with normal world, 121 * everything for uart0 is ready now. 122 */ 123 } 124