arch/ppc64/xmon/start.c

   1 /*
   2  * Copyright (C) 1996 Paul Mackerras.
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version
   7  *      2 of the License, or (at your option) any later version.
   8  */
   9 #include <linux/config.h>
  10 #include <linux/string.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/sysrq.h>
  14 #include <linux/init.h>
  15 #include <asm/machdep.h>
  16 #include <asm/io.h>
  17 #include <asm/page.h>
  18 #include <asm/prom.h>
  19 #include <asm/processor.h>
  20 #include <asm/udbg.h>
  21 #include <asm/system.h>
  22 #include "nonstdio.h"
  23
  24 #ifdef CONFIG_MAGIC_SYSRQ
  25
  26 static void sysrq_handle_xmon(int key, struct pt_regs *pt_regs,
  27                               struct tty_struct *tty)
  28 {
  29         /* ensure xmon is enabled */
  30         xmon_init(1);
  31         debugger(pt_regs);
  32 }
  33
  34 static struct sysrq_key_op sysrq_xmon_op =
  35 {
  36         .handler =      sysrq_handle_xmon,
  37         .help_msg =     "Xmon",
  38         .action_msg =   "Entering xmon",
  39 };
  40
  41 static int __init setup_xmon_sysrq(void)
  42 {
  43         register_sysrq_key('x', &sysrq_xmon_op);
  44         return 0;
  45 }
  46 __initcall(setup_xmon_sysrq);
  47 #endif /* CONFIG_MAGIC_SYSRQ */
  48
  49 int
  50 xmon_write(void *handle, void *ptr, int nb)
  51 {
  52         return udbg_write(ptr, nb);
  53 }
  54
  55 int
  56 xmon_read(void *handle, void *ptr, int nb)
  57 {
  58         return udbg_read(ptr, nb);
  59 }
  60
  61 int
  62 xmon_read_poll(void)
  63 {
  64         if (ppc_md.udbg_getc_poll)
  65                 return ppc_md.udbg_getc_poll();
  66         return -1;
  67 }
  68
  69 FILE *xmon_stdin;
  70 FILE *xmon_stdout;
  71
  72 int
  73 xmon_putc(int c, void *f)
  74 {
  75         char ch = c;
  76
  77         if (c == '\n')
  78                 xmon_putc('\r', f);
  79         return xmon_write(f, &ch, 1) == 1? c: -1;
  80 }
  81
  82 int
  83 xmon_putchar(int c)
  84 {
  85         return xmon_putc(c, xmon_stdout);
  86 }
  87
  88 int
  89 xmon_fputs(char *str, void *f)
  90 {
  91         int n = strlen(str);
  92
  93         return xmon_write(f, str, n) == n? 0: -1;
  94 }
  95
  96 int
  97 xmon_readchar(void)
  98 {
  99         char ch;
 100
 101         for (;;) {
 102                 switch (xmon_read(xmon_stdin, &ch, 1)) {
 103                 case 1:
 104                         return ch;
 105                 case -1:
 106                         xmon_printf("read(stdin) returned -1\r\n", 0, 0);
 107                         return -1;
 108                 }
 109         }
 110 }
 111
 112 static char line[256];
 113 static char *lineptr;
 114 static int lineleft;
 115
 116 int
 117 xmon_getchar(void)
 118 {
 119         int c;
 120
 121         if (lineleft == 0) {
 122                 lineptr = line;
 123                 for (;;) {
 124                         c = xmon_readchar();
 125                         if (c == -1 || c == 4)
 126                                 break;
 127                         if (c == '\r' || c == '\n') {
 128                                 *lineptr++ = '\n';
 129                                 xmon_putchar('\n');
 130                                 break;
 131                         }
 132                         switch (c) {
 133                         case 0177:
 134                         case '\b':
 135                                 if (lineptr > line) {
 136                                         xmon_putchar('\b');
 137                                         xmon_putchar(' ');
 138                                         xmon_putchar('\b');
 139                                         --lineptr;
 140                                 }
 141                                 break;
 142                         case 'U' & 0x1F:
 143                                 while (lineptr > line) {
 144                                         xmon_putchar('\b');
 145                                         xmon_putchar(' ');
 146                                         xmon_putchar('\b');
 147                                         --lineptr;
 148                                 }
 149                                 break;
 150                         default:
 151                                 if (lineptr >= &line[sizeof(line) - 1])
 152                                         xmon_putchar('\a');
 153                                 else {
 154                                         xmon_putchar(c);
 155                                         *lineptr++ = c;
 156                                 }
 157                         }
 158                 }
 159                 lineleft = lineptr - line;
 160                 lineptr = line;
 161         }
 162         if (lineleft == 0)
 163                 return -1;
 164         --lineleft;
 165         return *lineptr++;
 166 }
 167
 168 char *
 169 xmon_fgets(char *str, int nb, void *f)
 170 {
 171         char *p;
 172         int c;
 173
 174         for (p = str; p < str + nb - 1; ) {
 175                 c = xmon_getchar();
 176                 if (c == -1) {
 177                         if (p == str)
 178                                 return NULL;
 179                         break;
 180                 }
 181                 *p++ = c;
 182                 if (c == '\n')
 183                         break;
 184         }
 185         *p = 0;
 186         return str;
 187 }