arch/ppc64/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 #define WANT_PPCDBG_TAB /* Only defined here */
  14 #include <linux/config.h>
  15 #include <linux/types.h>
  16 #include <linux/sched.h>
  17 #include <linux/console.h>
  18 #include <asm/ppcdebug.h>
  19 #include <asm/processor.h>
  20
  21 void (*udbg_putc)(unsigned char c);
  22 unsigned char (*udbg_getc)(void);
  23 int (*udbg_getc_poll)(void);
  24
  25 /* udbg library, used by xmon et al */
  26 void udbg_puts(const char *s)
  27 {
  28         if (udbg_putc) {
  29                 char c;
  30
  31                 if (s && *s != '\0') {
  32                         while ((c = *s++) != '\0')
  33                                 udbg_putc(c);
  34                 }
  35         }
  36 #if 0
  37         else {
  38                 printk("%s", s);
  39         }
  40 #endif
  41 }
  42
  43 int udbg_write(const char *s, int n)
  44 {
  45         int remain = n;
  46         char c;
  47
  48         if (!udbg_putc)
  49                 return 0;
  50
  51         if (s && *s != '\0') {
  52                 while (((c = *s++) != '\0') && (remain-- > 0)) {
  53                         udbg_putc(c);
  54                 }
  55         }
  56
  57         return n - remain;
  58 }
  59
  60 int udbg_read(char *buf, int buflen)
  61 {
  62         char c, *p = buf;
  63         int i;
  64
  65         if (!udbg_getc)
  66                 return 0;
  67
  68         for (i = 0; i < buflen; ++i) {
  69                 do {
  70                         c = udbg_getc();
  71                 } while (c == 0x11 || c == 0x13);
  72                 if (c == 0)
  73                         break;
  74                 *p++ = c;
  75         }
  76
  77         return i;
  78 }
  79
  80 #define UDBG_BUFSIZE 256
  81 void udbg_printf(const char *fmt, ...)
  82 {
  83         unsigned char buf[UDBG_BUFSIZE];
  84         va_list args;
  85
  86         va_start(args, fmt);
  87         vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
  88         udbg_puts(buf);
  89         va_end(args);
  90 }
  91
  92 /* PPCDBG stuff */
  93
  94 u64 ppc64_debug_switch;
  95
  96 /* Special print used by PPCDBG() macro */
  97 void udbg_ppcdbg(unsigned long debug_flags, const char *fmt, ...)
  98 {
  99         unsigned long active_debugs = debug_flags & ppc64_debug_switch;
 100
 101         if (active_debugs) {
 102                 va_list ap;
 103                 unsigned char buf[UDBG_BUFSIZE];
 104                 unsigned long i, len = 0;
 105
 106                 for (i=0; i < PPCDBG_NUM_FLAGS; i++) {
 107                         if (((1U << i) & active_debugs) &&
 108                             trace_names[i]) {
 109                                 len += strlen(trace_names[i]);
 110                                 udbg_puts(trace_names[i]);
 111                                 break;
 112                         }
 113                 }
 114
 115                 snprintf(buf, UDBG_BUFSIZE, " [%s]: ", current->comm);
 116                 len += strlen(buf);
 117                 udbg_puts(buf);
 118
 119                 while (len < 18) {
 120                         udbg_puts(" ");
 121                         len++;
 122                 }
 123
 124                 va_start(ap, fmt);
 125                 vsnprintf(buf, UDBG_BUFSIZE, fmt, ap);
 126                 udbg_puts(buf);
 127                 va_end(ap);
 128         }
 129 }
 130
 131 unsigned long udbg_ifdebug(unsigned long flags)
 132 {
 133         return (flags & ppc64_debug_switch);
 134 }
 135
 136 /*
 137  * Initialize the PPCDBG state.  Called before relocation has been enabled.
 138  */
 139 void __init ppcdbg_initialize(void)
 140 {
 141         ppc64_debug_switch = PPC_DEBUG_DEFAULT; /* | PPCDBG_BUSWALK | */
 142         /* PPCDBG_PHBINIT | PPCDBG_MM | PPCDBG_MMINIT | PPCDBG_TCEINIT | PPCDBG_TCE */;
 143 }
 144
 145 /*
 146  * Early boot console based on udbg
 147  */
 148 static void udbg_console_write(struct console *con, const char *s,
 149                 unsigned int n)
 150 {
 151         udbg_write(s, n);
 152 }
 153
 154 static struct console udbg_console = {
 155         .name   = "udbg",
 156         .write  = udbg_console_write,
 157         .flags  = CON_PRINTBUFFER,
 158         .index  = -1,
 159 };
 160
 161 static int early_console_initialized;
 162
 163 void __init disable_early_printk(void)
 164 {
 165         if (!early_console_initialized)
 166                 return;
 167         unregister_console(&udbg_console);
 168         early_console_initialized = 0;
 169 }
 170
 171 /* called by setup_system */
 172 void register_early_udbg_console(void)
 173 {
 174         early_console_initialized = 1;
 175         register_console(&udbg_console);
 176 }
 177
 178 #if 0   /* if you want to use this as a regular output console */
 179 console_initcall(register_udbg_console);
 180 #endif