arch/powerpc/kernel/udbg.c

   1 /*
   2  * polling mode stateless debugging stuff, originally for NS16550 Serial Ports
   3  *
   4  * c 2001 PPC 64 Team, IBM Corp
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <stdarg.h>
  13 #include <linux/config.h>
  14 #include <linux/types.h>
  15 #include <linux/sched.h>
  16 #include <linux/console.h>
  17 #include <linux/init.h>
  18 #include <asm/processor.h>
  19 #include <asm/udbg.h>
  20
  21 void (*udbg_putc)(char c);
  22 int (*udbg_getc)(void);
  23 int (*udbg_getc_poll)(void);
  24
  25 /*
  26  * Early debugging facilities. You can enable _one_ of these via .config,
  27  * if you do so your kernel _will not boot_ on anything else. Be careful.
  28  */
  29 void __init udbg_early_init(void)
  30 {
  31 #if defined(CONFIG_PPC_EARLY_DEBUG_LPAR)
  32         /* For LPAR machines that have an HVC console on vterm 0 */
  33         udbg_init_debug_lpar();
  34 #elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
  35         /* For use on Apple G5 machines */
  36         udbg_init_pmac_realmode();
  37 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS)
  38         /* RTAS panel debug */
  39         udbg_init_rtas();
  40 #elif defined(CONFIG_PPC_EARLY_DEBUG_MAPLE)
  41         /* Maple real mode debug */
  42         udbg_init_maple_realmode();
  43 #elif defined(CONFIG_PPC_EARLY_DEBUG_ISERIES)
  44         /* For iSeries - hit Ctrl-x Ctrl-x to see the output */
  45         udbg_init_iseries();
  46 #endif
  47 }
  48
  49 /* udbg library, used by xmon et al */
  50 void udbg_puts(const char *s)
  51 {
  52         if (udbg_putc) {
  53                 char c;
  54
  55                 if (s && *s != '\0') {
  56                         while ((c = *s++) != '\0')
  57                                 udbg_putc(c);
  58                 }
  59         }
  60 #if 0
  61         else {
  62                 printk("%s", s);
  63         }
  64 #endif
  65 }
  66
  67 int udbg_write(const char *s, int n)
  68 {
  69         int remain = n;
  70         char c;
  71
  72         if (!udbg_putc)
  73                 return 0;
  74
  75         if (s && *s != '\0') {
  76                 while (((c = *s++) != '\0') && (remain-- > 0)) {
  77                         udbg_putc(c);
  78                 }
  79         }
  80
  81         return n - remain;
  82 }
  83
  84 int udbg_read(char *buf, int buflen)
  85 {
  86         char *p = buf;
  87         int i, c;
  88
  89         if (!udbg_getc)
  90                 return 0;
  91
  92         for (i = 0; i < buflen; ++i) {
  93                 do {
  94                         c = udbg_getc();
  95                         if (c == -1 && i == 0)
  96                                 return -1;
  97
  98                 } while (c == 0x11 || c == 0x13);
  99                 if (c == 0 || c == -1)
 100                         break;
 101                 *p++ = c;
 102         }
 103
 104         return i;
 105 }
 106
 107 #define UDBG_BUFSIZE 256
 108 void udbg_printf(const char *fmt, ...)
 109 {
 110         char buf[UDBG_BUFSIZE];
 111         va_list args;
 112
 113         va_start(args, fmt);
 114         vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
 115         udbg_puts(buf);
 116         va_end(args);
 117 }
 118
 119 void __init udbg_progress(char *s, unsigned short hex)
 120 {
 121         udbg_puts(s);
 122         udbg_puts("\n");
 123 }
 124
 125 /*
 126  * Early boot console based on udbg
 127  */
 128 static void udbg_console_write(struct console *con, const char *s,
 129                 unsigned int n)
 130 {
 131         udbg_write(s, n);
 132 }
 133
 134 static struct console udbg_console = {
 135         .name   = "udbg",
 136         .write  = udbg_console_write,
 137         .flags  = CON_PRINTBUFFER | CON_ENABLED,
 138         .index  = -1,
 139 };
 140
 141 static int early_console_initialized;
 142
 143 void __init disable_early_printk(void)
 144 {
 145         if (!early_console_initialized)
 146                 return;
 147         if (strstr(saved_command_line, "udbg-immortal")) {
 148                 printk(KERN_INFO "early console immortal !\n");
 149                 return;
 150         }
 151         unregister_console(&udbg_console);
 152         early_console_initialized = 0;
 153 }
 154
 155 /* called by setup_system */
 156 void register_early_udbg_console(void)
 157 {
 158         if (early_console_initialized)
 159                 return;
 160         early_console_initialized = 1;
 161         register_console(&udbg_console);
 162 }
 163
 164 #if 0   /* if you want to use this as a regular output console */
 165 console_initcall(register_udbg_console);
 166 #endif