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 #elif defined(CONFIG_PPC_EARLY_DEBUG_BEAT)
  49         udbg_init_debug_beat();
  50 #elif defined(CONFIG_PPC_EARLY_DEBUG_PAS_REALMODE)
  51         udbg_init_pas_realmode();
  52 #elif defined(CONFIG_BOOTX_TEXT)
  53         udbg_init_btext();
  54 #endif
  55 }
  56
  57 /* udbg library, used by xmon et al */
  58 void udbg_puts(const char *s)
  59 {
  60         if (udbg_putc) {
  61                 char c;
  62
  63                 if (s && *s != '\0') {
  64                         while ((c = *s++) != '\0')
  65                                 udbg_putc(c);
  66                 }
  67         }
  68 #if 0
  69         else {
  70                 printk("%s", s);
  71         }
  72 #endif
  73 }
  74
  75 int udbg_write(const char *s, int n)
  76 {
  77         int remain = n;
  78         char c;
  79
  80         if (!udbg_putc)
  81                 return 0;
  82
  83         if (s && *s != '\0') {
  84                 while (((c = *s++) != '\0') && (remain-- > 0)) {
  85                         udbg_putc(c);
  86                 }
  87         }
  88
  89         return n - remain;
  90 }
  91
  92 int udbg_read(char *buf, int buflen)
  93 {
  94         char *p = buf;
  95         int i, c;
  96
  97         if (!udbg_getc)
  98                 return 0;
  99
 100         for (i = 0; i < buflen; ++i) {
 101                 do {
 102                         c = udbg_getc();
 103                         if (c == -1 && i == 0)
 104                                 return -1;
 105
 106                 } while (c == 0x11 || c == 0x13);
 107                 if (c == 0 || c == -1)
 108                         break;
 109                 *p++ = c;
 110         }
 111
 112         return i;
 113 }
 114
 115 #define UDBG_BUFSIZE 256
 116 void udbg_printf(const char *fmt, ...)
 117 {
 118         char buf[UDBG_BUFSIZE];
 119         va_list args;
 120
 121         va_start(args, fmt);
 122         vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
 123         udbg_puts(buf);
 124         va_end(args);
 125 }
 126
 127 void __init udbg_progress(char *s, unsigned short hex)
 128 {
 129         udbg_puts(s);
 130         udbg_puts("\n");
 131 }
 132
 133 /*
 134  * Early boot console based on udbg
 135  */
 136 static void udbg_console_write(struct console *con, const char *s,
 137                 unsigned int n)
 138 {
 139         udbg_write(s, n);
 140 }
 141
 142 static struct console udbg_console = {
 143         .name   = "udbg",
 144         .write  = udbg_console_write,
 145         .flags  = CON_PRINTBUFFER | CON_ENABLED,
 146         .index  = -1,
 147 };
 148
 149 static int early_console_initialized;
 150
 151 void __init disable_early_printk(void)
 152 {
 153         if (!early_console_initialized)
 154                 return;
 155         if (strstr(boot_command_line, "udbg-immortal")) {
 156                 printk(KERN_INFO "early console immortal !\n");
 157                 return;
 158         }
 159         unregister_console(&udbg_console);
 160         early_console_initialized = 0;
 161 }
 162
 163 /* called by setup_system */
 164 void register_early_udbg_console(void)
 165 {
 166         if (early_console_initialized)
 167                 return;
 168         early_console_initialized = 1;
 169         register_console(&udbg_console);
 170 }
 171
 172 #if 0   /* if you want to use this as a regular output console */
 173 console_initcall(register_udbg_console);
 174 #endif