xref: /openbmc/linux/arch/m68k/kernel/early_printk.c (revision 6c33a6f4)
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 extern void mvme16x_cons_write(struct console *co,
16 			       const char *str, unsigned count);
17 
18 asmlinkage void __init debug_cons_nputs(const char *s, unsigned n);
19 
20 static void __ref debug_cons_write(struct console *c,
21 				   const char *s, unsigned n)
22 {
23 #if !(defined(CONFIG_SUN3) || defined(CONFIG_M68000) || \
24       defined(CONFIG_COLDFIRE))
25 	if (MACH_IS_MVME16x)
26 		mvme16x_cons_write(c, s, n);
27 	else
28 		debug_cons_nputs(s, n);
29 #endif
30 }
31 
32 static struct console early_console_instance = {
33 	.name  = "debug",
34 	.write = debug_cons_write,
35 	.flags = CON_PRINTBUFFER | CON_BOOT,
36 	.index = -1
37 };
38 
39 static int __init setup_early_printk(char *buf)
40 {
41 	if (early_console || buf)
42 		return 0;
43 
44 	early_console = &early_console_instance;
45 	register_console(early_console);
46 
47 	return 0;
48 }
49 early_param("earlyprintk", setup_early_printk);
50 
51 /*
52  * debug_cons_nputs() defined in arch/m68k/kernel/head.S cannot be called
53  * after init sections are discarded (for platforms that use it).
54  */
55 #if !(defined(CONFIG_SUN3) || defined(CONFIG_M68000) || \
56       defined(CONFIG_COLDFIRE))
57 
58 static int __init unregister_early_console(void)
59 {
60 	if (!early_console || MACH_IS_MVME16x)
61 		return 0;
62 
63 	return unregister_console(early_console);
64 }
65 late_initcall(unregister_early_console);
66 
67 #endif
68