1 /* 2 * Copyright (C) 2004-2007 ARM Limited. 3 * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License version 2 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * As a special exception, if other files instantiate templates or use macros 19 * or inline functions from this file, or you compile this file and link it 20 * with other works to produce a work based on this file, this file does not 21 * by itself cause the resulting work to be covered by the GNU General Public 22 * License. However the source code for this file must still be made available 23 * in accordance with section (3) of the GNU General Public License. 24 25 * This exception does not invalidate any other reasons why a work based on 26 * this file might be covered by the GNU General Public License. 27 */ 28 29 #include <common.h> 30 #include <serial.h> 31 32 #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V7) 33 /* 34 * ARMV6 & ARMV7 35 */ 36 #define DCC_RBIT (1 << 30) 37 #define DCC_WBIT (1 << 29) 38 39 #define write_dcc(x) \ 40 __asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x)) 41 42 #define read_dcc(x) \ 43 __asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x)) 44 45 #define status_dcc(x) \ 46 __asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x)) 47 48 #elif defined(CONFIG_CPU_XSCALE) 49 /* 50 * XSCALE 51 */ 52 #define DCC_RBIT (1 << 31) 53 #define DCC_WBIT (1 << 28) 54 55 #define write_dcc(x) \ 56 __asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x)) 57 58 #define read_dcc(x) \ 59 __asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x)) 60 61 #define status_dcc(x) \ 62 __asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x)) 63 64 #elif defined(CONFIG_CPU_ARMV8) 65 /* 66 * ARMV8 67 */ 68 #define DCC_RBIT (1 << 30) 69 #define DCC_WBIT (1 << 29) 70 71 #define write_dcc(x) \ 72 __asm__ volatile ("msr dbgdtrtx_el0, %0\n" : : "r" (x)) 73 74 #define read_dcc(x) \ 75 __asm__ volatile ("mrs %0, dbgdtrrx_el0\n" : "=r" (x)) 76 77 #define status_dcc(x) \ 78 __asm__ volatile ("mrs %0, mdccsr_el0\n" : "=r" (x)) 79 80 #else 81 #define DCC_RBIT (1 << 0) 82 #define DCC_WBIT (1 << 1) 83 84 #define write_dcc(x) \ 85 __asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x)) 86 87 #define read_dcc(x) \ 88 __asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x)) 89 90 #define status_dcc(x) \ 91 __asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x)) 92 93 #endif 94 95 #define can_read_dcc(x) do { \ 96 status_dcc(x); \ 97 x &= DCC_RBIT; \ 98 } while (0); 99 100 #define can_write_dcc(x) do { \ 101 status_dcc(x); \ 102 x &= DCC_WBIT; \ 103 x = (x == 0); \ 104 } while (0); 105 106 #define TIMEOUT_COUNT 0x4000000 107 108 static int arm_dcc_init(void) 109 { 110 return 0; 111 } 112 113 static int arm_dcc_getc(void) 114 { 115 int ch; 116 register unsigned int reg; 117 118 do { 119 can_read_dcc(reg); 120 } while (!reg); 121 read_dcc(ch); 122 123 return ch; 124 } 125 126 static void arm_dcc_putc(char ch) 127 { 128 register unsigned int reg; 129 unsigned int timeout_count = TIMEOUT_COUNT; 130 131 while (--timeout_count) { 132 can_write_dcc(reg); 133 if (reg) 134 break; 135 } 136 if (timeout_count == 0) 137 return; 138 else 139 write_dcc(ch); 140 } 141 142 static int arm_dcc_tstc(void) 143 { 144 register unsigned int reg; 145 146 can_read_dcc(reg); 147 148 return reg; 149 } 150 151 static void arm_dcc_setbrg(void) 152 { 153 } 154 155 static struct serial_device arm_dcc_drv = { 156 .name = "arm_dcc", 157 .start = arm_dcc_init, 158 .stop = NULL, 159 .setbrg = arm_dcc_setbrg, 160 .putc = arm_dcc_putc, 161 .puts = default_serial_puts, 162 .getc = arm_dcc_getc, 163 .tstc = arm_dcc_tstc, 164 }; 165 166 void arm_dcc_initialize(void) 167 { 168 serial_register(&arm_dcc_drv); 169 } 170 171 __weak struct serial_device *default_serial_console(void) 172 { 173 return &arm_dcc_drv; 174 } 175