xref: /linux/arch/m68k/kernel/early_printk.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
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
71