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