xref: /openbmc/linux/arch/sparc/prom/printf.c (revision b6dcefde)
1 /*
2  * printf.c:  Internal prom library printf facility.
3  *
4  * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
5  * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
6  * Copyright (c) 2002 Pete Zaitcev (zaitcev@yahoo.com)
7  *
8  * We used to warn all over the code: DO NOT USE prom_printf(),
9  * and yet people do. Anton's banking code was outputting banks
10  * with prom_printf for most of the 2.4 lifetime. Since an effective
11  * stick is not available, we deployed a carrot: an early printk
12  * through PROM by means of -p boot option. This ought to fix it.
13  * USE printk; if you need, deploy -p.
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/compiler.h>
18 
19 #include <asm/openprom.h>
20 #include <asm/oplib.h>
21 
22 static char ppbuf[1024];
23 
24 void notrace prom_write(const char *buf, unsigned int n)
25 {
26 	char ch;
27 
28 	while (n != 0) {
29 		--n;
30 		if ((ch = *buf++) == '\n')
31 			prom_putchar('\r');
32 		prom_putchar(ch);
33 	}
34 }
35 
36 void notrace prom_printf(const char *fmt, ...)
37 {
38 	va_list args;
39 	int i;
40 
41 	va_start(args, fmt);
42 	i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
43 	va_end(args);
44 
45 	prom_write(ppbuf, i);
46 }
47