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 #elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
  55         /* PPC44x debug */
  56         udbg_init_44x_as1();
  57 #endif
  58 }
  59
  60 /* udbg library, used by xmon et al */
  61 void udbg_puts(const char *s)
  62 {
  63         if (udbg_putc) {
  64                 char c;
  65
  66                 if (s && *s != '\0') {
  67                         while ((c = *s++) != '\0')
  68                                 udbg_putc(c);
  69                 }
  70         }
  71 #if 0
  72         else {
  73                 printk("%s", s);
  74         }
  75 #endif
  76 }
  77
  78 int udbg_write(const char *s, int n)
  79 {
  80         int remain = n;
  81         char c;
  82
  83         if (!udbg_putc)
  84                 return 0;
  85
  86         if (s && *s != '\0') {
  87                 while (((c = *s++) != '\0') && (remain-- > 0)) {
  88                         udbg_putc(c);
  89                 }
  90         }
  91
  92         return n - remain;
  93 }
  94
  95 int udbg_read(char *buf, int buflen)
  96 {
  97         char *p = buf;
  98         int i, c;
  99
 100         if (!udbg_getc)
 101                 return 0;
 102
 103         for (i = 0; i < buflen; ++i) {
 104                 do {
 105                         c = udbg_getc();
 106                         if (c == -1 && i == 0)
 107                                 return -1;
 108
 109                 } while (c == 0x11 || c == 0x13);
 110                 if (c == 0 || c == -1)
 111                         break;
 112                 *p++ = c;
 113         }
 114
 115         return i;
 116 }
 117
 118 #define UDBG_BUFSIZE 256
 119 void udbg_printf(const char *fmt, ...)
 120 {
 121         char buf[UDBG_BUFSIZE];
 122         va_list args;
 123
 124         va_start(args, fmt);
 125         vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
 126         udbg_puts(buf);
 127         va_end(args);
 128 }
 129
 130 void __init udbg_progress(char *s, unsigned short hex)
 131 {
 132         udbg_puts(s);
 133         udbg_puts("\n");
 134 }
 135
 136 /*
 137  * Early boot console based on udbg
 138  */
 139 static void udbg_console_write(struct console *con, const char *s,
 140                 unsigned int n)
 141 {
 142         udbg_write(s, n);
 143 }
 144
 145 static struct console udbg_console = {
 146         .name   = "udbg",
 147         .write  = udbg_console_write,
 148         .flags  = CON_PRINTBUFFER | CON_ENABLED,
 149         .index  = -1,
 150 };
 151
 152 static int early_console_initialized;
 153
 154 void __init disable_early_printk(void)
 155 {
 156         if (!early_console_initialized)
 157                 return;
 158         if (strstr(boot_command_line, "udbg-immortal")) {
 159                 printk(KERN_INFO "early console immortal !\n");
 160                 return;
 161         }
 162         unregister_console(&udbg_console);
 163         early_console_initialized = 0;
 164 }
 165
 166 /* called by setup_system */
 167 void register_early_udbg_console(void)
 168 {
 169         if (early_console_initialized)
 170                 return;
 171         early_console_initialized = 1;
 172         register_console(&udbg_console);
 173 }
 174
 175 #if 0   /* if you want to use this as a regular output console */
 176 console_initcall(register_udbg_console);
 177 #endif