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