1 /* 2 * Copyright (c) 2015, Linaro Limited 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 11 * 2. Redistributions in binary form must reproduce the above copyright notice, 12 * this list of conditions and the following disclaimer in the documentation 13 * and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25 * POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #include <platform_config.h> 28 29 #include <drivers/serial8250_uart.h> 30 #include <console.h> 31 #include <io.h> 32 #include <compiler.h> 33 34 /* uart register defines */ 35 #define UART_RHR 0x0 36 #define UART_THR 0x0 37 #define UART_IER 0x4 38 #define UART_ISR 0x8 39 #define UART_FCR 0x8 40 #define UART_LCR 0xc 41 #define UART_MCR 0x10 42 #define UART_LSR 0x14 43 #define UART_MSR 0x18 44 #define UART_SPR 0x1c 45 46 /* uart status register bits */ 47 #define LSR_TEMT 0x40 /* Transmitter empty */ 48 #define LSR_THRE 0x20 /* Transmit-hold-register empty */ 49 #define LSR_EMPTY (LSR_TEMT | LSR_THRE) 50 #define LSR_DR 0x01 /* DATA Ready */ 51 52 void serial8250_uart_init(vaddr_t __unused base, 53 uint32_t __unused uart_clk, uint32_t __unused baud_rate) 54 { 55 /* 56 * do nothing, debug uart(uart0) share with normal world, 57 * everything for uart0 is ready now. 58 */ 59 } 60 61 void serial8250_uart_flush_tx_fifo(vaddr_t base) 62 { 63 while (1) { 64 uint8_t state = read8(base + UART_LSR); 65 66 /* waiting transmit fifo empty */ 67 if ((state & LSR_EMPTY) == LSR_EMPTY) 68 break; 69 } 70 } 71 72 bool serial8250_uart_have_rx_data(vaddr_t base) 73 { 74 return (read32(base + UART_LSR) & LSR_DR); 75 } 76 77 void serial8250_uart_putc(int ch, vaddr_t base) 78 { 79 serial8250_uart_flush_tx_fifo(base); 80 81 /* write out charset to transmit fifo */ 82 write8(ch, base + UART_THR); 83 } 84 85 int serial8250_uart_getchar(vaddr_t base) 86 { 87 while (!serial8250_uart_have_rx_data(base)) { 88 /* transmit fifo is empty, waiting again. */ 89 ; 90 } 91 return read8(base + UART_RHR); 92 } 93 94