arch/unicore32/kernel/early_printk.c

   1 /*
   2  * linux/arch/unicore32/kernel/early_printk.c
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #include <linux/console.h>
  13 #include <linux/init.h>
  14 #include <linux/string.h>
  15 #include <mach/ocd.h>
  16
  17 /* On-Chip-Debugger functions */
  18
  19 static void early_ocd_write(struct console *con, const char *s, unsigned n)
  20 {
  21         while (*s && n-- > 0) {
  22                 if (*s == '\n')
  23                         ocd_putc((int)'\r');
  24                 ocd_putc((int)*s);
  25                 s++;
  26         }
  27 }
  28
  29 static struct console early_ocd_console = {
  30         .name =         "earlyocd",
  31         .write =        early_ocd_write,
  32         .flags =        CON_PRINTBUFFER,
  33         .index =        -1,
  34 };
  35
  36 /* Direct interface for emergencies */
  37 static struct console *early_console = &early_ocd_console;
  38
  39 static int __initdata keep_early;
  40
  41 static int __init setup_early_printk(char *buf)
  42 {
  43         if (!buf)
  44                 return 0;
  45
  46         if (strstr(buf, "keep"))
  47                 keep_early = 1;
  48
  49         if (!strncmp(buf, "ocd", 3))
  50                 early_console = &early_ocd_console;
  51
  52         if (keep_early)
  53                 early_console->flags &= ~CON_BOOT;
  54         else
  55                 early_console->flags |= CON_BOOT;
  56         register_console(early_console);
  57         return 0;
  58 }
  59 early_param("earlyprintk", setup_early_printk);