1 /* 2 * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 #include <asm_macros.S> 7 8 .globl console_init 9 .globl console_uninit 10 .globl console_putc 11 .globl console_getc 12 .globl console_flush 13 14 /* 15 * The console base is in the data section and not in .bss 16 * even though it is zero-init. In particular, this allows 17 * the console functions to start using this variable before 18 * the runtime memory is initialized for images which do not 19 * need to copy the .data section from ROM to RAM. 20 */ 21 .section .data.console_base ; .align 2 22 console_base: .word 0x0 23 24 /* ----------------------------------------------- 25 * int console_init(uintptr_t base_addr, 26 * unsigned int uart_clk, unsigned int baud_rate) 27 * Function to initialize the console without a 28 * C Runtime to print debug information. It saves 29 * the console base to the data section. 30 * In: r0 - console base address 31 * r1 - Uart clock in Hz 32 * r2 - Baud rate 33 * out: return 1 on success else 0 on error 34 * Clobber list : r1 - r3 35 * ----------------------------------------------- 36 */ 37 func console_init 38 /* Check the input base address */ 39 cmp r0, #0 40 beq init_fail 41 ldr r3, =console_base 42 str r0, [r3] 43 b console_core_init 44 init_fail: 45 bx lr 46 endfunc console_init 47 48 /* ----------------------------------------------- 49 * void console_uninit(void) 50 * Function to finish the use of console driver. 51 * It sets the console_base as NULL so that any 52 * further invocation of `console_putc` or 53 * `console_getc` APIs would return error. 54 * ----------------------------------------------- 55 */ 56 func console_uninit 57 mov r0, #0 58 ldr r3, =console_base 59 str r0, [r3] 60 bx lr 61 endfunc console_uninit 62 63 /* --------------------------------------------- 64 * int console_putc(int c) 65 * Function to output a character over the 66 * console. It returns the character printed on 67 * success or -1 on error. 68 * In : r0 - character to be printed 69 * Out : return -1 on error else return character. 70 * Clobber list : r1, r2 71 * --------------------------------------------- 72 */ 73 func console_putc 74 ldr r2, =console_base 75 ldr r1, [r2] 76 b console_core_putc 77 endfunc console_putc 78 79 /* --------------------------------------------- 80 * int console_getc(void) 81 * Function to get a character from the console. 82 * It returns the character grabbed on success 83 * or -1 on error. 84 * Clobber list : r0, r1 85 * --------------------------------------------- 86 */ 87 func console_getc 88 ldr r1, =console_base 89 ldr r0, [r1] 90 b console_core_getc 91 endfunc console_getc 92 93 /* --------------------------------------------- 94 * int console_flush(void) 95 * Function to force a write of all buffered 96 * data that hasn't been output. It returns 0 97 * upon successful completion, otherwise it 98 * returns -1. 99 * Clobber list : r0, r1 100 * --------------------------------------------- 101 */ 102 func console_flush 103 ldr r1, =console_base 104 ldr r0, [r1] 105 b console_core_flush 106 endfunc console_flush 107
