Linux Kernel  3.7.1
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early_printk.c
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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);