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
18 #include <asm/openprom.h>
19 #include <asm/oplib.h>
20
21 static char ppbuf[1024];
22
23 void
prom_write(const char * buf,unsigned int n)24 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
prom_printf(const char * fmt,...)37 prom_printf(const char *fmt, ...)
38 {
39 va_list args;
40 int i;
41
42 va_start(args, fmt);
43 i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
44 va_end(args);
45
46 prom_write(ppbuf, i);
47 }
48