1 /* 2 * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <arch.h> 8 #include <asm_macros.S> 9 #include <uart_16550.h> 10 11 .globl console_core_init 12 .globl console_core_putc 13 .globl console_core_getc 14 .globl console_core_flush 15 16 /* ----------------------------------------------- 17 * int console_core_init(unsigned long base_addr, 18 * unsigned int uart_clk, unsigned int baud_rate) 19 * Function to initialize the console without a 20 * C Runtime to print debug information. This 21 * function will be accessed by console_init and 22 * crash reporting. 23 * In: x0 - console base address 24 * w1 - Uart clock in Hz 25 * w2 - Baud rate 26 * Out: return 1 on success 27 * Clobber list : x1, x2, x3 28 * ----------------------------------------------- 29 */ 30 func console_core_init 31 /* Check the input base address */ 32 cbz x0, init_fail 33 /* Check baud rate and uart clock for sanity */ 34 cbz w1, init_fail 35 cbz w2, init_fail 36 37 /* Program the baudrate */ 38 /* Divisor = Uart clock / (16 * baudrate) */ 39 lsl w2, w2, #4 40 udiv w2, w1, w2 41 and w1, w2, #0xff /* w1 = DLL */ 42 lsr w2, w2, #8 43 and w2, w2, #0xff /* w2 = DLLM */ 44 ldr w3, [x0, #UARTLCR] 45 orr w3, w3, #UARTLCR_DLAB 46 str w3, [x0, #UARTLCR] /* enable DLL, DLLM programming */ 47 str w1, [x0, #UARTDLL] /* program DLL */ 48 str w2, [x0, #UARTDLLM] /* program DLLM */ 49 mov w2, #~UARTLCR_DLAB 50 and w3, w3, w2 51 str w3, [x0, #UARTLCR] /* disable DLL, DLLM programming */ 52 53 /* 8n1 */ 54 mov w3, #3 55 str w3, [x0, #UARTLCR] 56 /* no interrupt */ 57 mov w3, #0 58 str w3, [x0, #UARTIER] 59 /* enable fifo, DMA */ 60 mov w3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN) 61 str w3, [x0, #UARTFCR] 62 /* DTR + RTS */ 63 mov w3, #3 64 str w3, [x0, #UARTMCR] 65 mov w0, #1 66 init_fail: 67 ret 68 endfunc console_core_init 69 70 /* -------------------------------------------------------- 71 * int console_core_putc(int c, unsigned int base_addr) 72 * Function to output a character over the console. It 73 * returns the character printed on success or -1 on error. 74 * In : w0 - character to be printed 75 * x1 - console base address 76 * Out : return -1 on error else return character. 77 * Clobber list : x2 78 * -------------------------------------------------------- 79 */ 80 func console_core_putc 81 /* Check the input parameter */ 82 cbz x1, putc_error 83 84 /* Prepend '\r' to '\n' */ 85 cmp w0, #0xA 86 b.ne 2f 87 /* Check if the transmit FIFO is full */ 88 1: ldr w2, [x1, #UARTLSR] 89 and w2, w2, #(UARTLSR_TEMT | UARTLSR_THRE) 90 cmp w2, #(UARTLSR_TEMT | UARTLSR_THRE) 91 b.ne 1b 92 mov w2, #0xD /* '\r' */ 93 str w2, [x1, #UARTTX] 94 95 /* Check if the transmit FIFO is full */ 96 2: ldr w2, [x1, #UARTLSR] 97 and w2, w2, #(UARTLSR_TEMT | UARTLSR_THRE) 98 cmp w2, #(UARTLSR_TEMT | UARTLSR_THRE) 99 b.ne 2b 100 str w0, [x1, #UARTTX] 101 ret 102 putc_error: 103 mov w0, #-1 104 ret 105 endfunc console_core_putc 106 107 /* --------------------------------------------- 108 * int console_core_getc(void) 109 * Function to get a character from the console. 110 * It returns the character grabbed on success 111 * or -1 on error. 112 * In : w0 - console base address 113 * Out : return -1 on error else return character. 114 * Clobber list : x0, x1 115 * --------------------------------------------- 116 */ 117 func console_core_getc 118 /* Check if the receive FIFO is empty */ 119 1: ldr w1, [x0, #UARTLSR] 120 tbz w1, #UARTLSR_RDR_BIT, 1b 121 ldr w0, [x0, #UARTRX] 122 ret 123 getc_error: 124 mov w0, #-1 125 ret 126 endfunc console_core_getc 127 128 /* --------------------------------------------- 129 * int console_core_flush(uintptr_t base_addr) 130 * Function to force a write of all buffered 131 * data that hasn't been output. 132 * In : x0 - console base address 133 * Out : return -1 on error else return 0. 134 * Clobber list : x0, x1 135 * --------------------------------------------- 136 */ 137 func console_core_flush 138 /* Placeholder */ 139 mov w0, #0 140 ret 141 endfunc console_core_flush 142
