arch/m68k/kernel/early_printk.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (c) 2014 Finn Thain
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/console.h>
  11 #include <linux/init.h>
  12 #include <linux/string.h>
  13 #include <asm/setup.h>
  14
  15
  16 #include "../mvme147/mvme147.h"
  17 #include "../mvme16x/mvme16x.h"
  18
  19 asmlinkage void __init debug_cons_nputs(const char *s, unsigned n);
  20
  21 static void __ref debug_cons_write(struct console *c,
  22                                    const char *s, unsigned n)
  23 {
  24 #if !(defined(CONFIG_SUN3) || defined(CONFIG_M68000) || \
  25       defined(CONFIG_COLDFIRE))
  26         if (MACH_IS_MVME147)
  27                 mvme147_scc_write(c, s, n);
  28         else if (MACH_IS_MVME16x)
  29                 mvme16x_cons_write(c, s, n);
  30         else
  31                 debug_cons_nputs(s, n);
  32 #endif
  33 }
  34
  35 static struct console early_console_instance = {
  36         .name  = "debug",
  37         .write = debug_cons_write,
  38         .flags = CON_PRINTBUFFER | CON_BOOT,
  39         .index = -1
  40 };
  41
  42 static int __init setup_early_printk(char *buf)
  43 {
  44         if (early_console || buf)
  45                 return 0;
  46
  47         early_console = &early_console_instance;
  48         register_console(early_console);
  49
  50         return 0;
  51 }
  52 early_param("earlyprintk", setup_early_printk);
  53
  54 /*
  55  * debug_cons_nputs() defined in arch/m68k/kernel/head.S cannot be called
  56  * after init sections are discarded (for platforms that use it).
  57  */
  58 #if !(defined(CONFIG_SUN3) || defined(CONFIG_M68000) || \
  59       defined(CONFIG_COLDFIRE))
  60
  61 static int __init unregister_early_console(void)
  62 {
  63         if (!early_console || MACH_IS_MVME16x)
  64                 return 0;
  65
  66         return unregister_console(early_console);
  67 }
  68 late_initcall(unregister_early_console);
  69
  70 #endif