1*b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
2efe6c3ddSRobert Reif /*
3efe6c3ddSRobert Reif * printf.c: Internal prom library printf facility.
4efe6c3ddSRobert Reif *
5efe6c3ddSRobert Reif * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
6efe6c3ddSRobert Reif * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7efe6c3ddSRobert Reif * Copyright (c) 2002 Pete Zaitcev (zaitcev@yahoo.com)
8efe6c3ddSRobert Reif *
9efe6c3ddSRobert Reif * We used to warn all over the code: DO NOT USE prom_printf(),
10efe6c3ddSRobert Reif * and yet people do. Anton's banking code was outputting banks
11efe6c3ddSRobert Reif * with prom_printf for most of the 2.4 lifetime. Since an effective
12efe6c3ddSRobert Reif * stick is not available, we deployed a carrot: an early printk
13efe6c3ddSRobert Reif * through PROM by means of -p boot option. This ought to fix it.
14efe6c3ddSRobert Reif * USE printk; if you need, deploy -p.
15efe6c3ddSRobert Reif */
16efe6c3ddSRobert Reif
17efe6c3ddSRobert Reif #include <linux/kernel.h>
18bd4352caSDavid S. Miller #include <linux/compiler.h>
19595a251cSDavid S. Miller #include <linux/spinlock.h>
20efe6c3ddSRobert Reif
21efe6c3ddSRobert Reif #include <asm/openprom.h>
22efe6c3ddSRobert Reif #include <asm/oplib.h>
23efe6c3ddSRobert Reif
24595a251cSDavid S. Miller #define CONSOLE_WRITE_BUF_SIZE 1024
25595a251cSDavid S. Miller
26efe6c3ddSRobert Reif static char ppbuf[1024];
27595a251cSDavid S. Miller static char console_write_buf[CONSOLE_WRITE_BUF_SIZE];
28595a251cSDavid S. Miller static DEFINE_RAW_SPINLOCK(console_write_lock);
29efe6c3ddSRobert Reif
prom_write(const char * buf,unsigned int n)30bd4352caSDavid S. Miller void notrace prom_write(const char *buf, unsigned int n)
31efe6c3ddSRobert Reif {
32595a251cSDavid S. Miller unsigned int dest_len;
33595a251cSDavid S. Miller unsigned long flags;
34595a251cSDavid S. Miller char *dest;
35595a251cSDavid S. Miller
36595a251cSDavid S. Miller dest = console_write_buf;
37595a251cSDavid S. Miller raw_spin_lock_irqsave(&console_write_lock, flags);
38595a251cSDavid S. Miller
39595a251cSDavid S. Miller dest_len = 0;
40e62cac1fSDavid S. Miller while (n-- != 0) {
41595a251cSDavid S. Miller char ch = *buf++;
42e62cac1fSDavid S. Miller if (ch == '\n') {
43595a251cSDavid S. Miller *dest++ = '\r';
44595a251cSDavid S. Miller dest_len++;
45e62cac1fSDavid S. Miller }
46595a251cSDavid S. Miller *dest++ = ch;
47595a251cSDavid S. Miller dest_len++;
48595a251cSDavid S. Miller if (dest_len >= CONSOLE_WRITE_BUF_SIZE - 1) {
49595a251cSDavid S. Miller prom_console_write_buf(console_write_buf, dest_len);
50595a251cSDavid S. Miller dest = console_write_buf;
51595a251cSDavid S. Miller dest_len = 0;
52efe6c3ddSRobert Reif }
53efe6c3ddSRobert Reif }
54595a251cSDavid S. Miller if (dest_len)
55595a251cSDavid S. Miller prom_console_write_buf(console_write_buf, dest_len);
56595a251cSDavid S. Miller
57595a251cSDavid S. Miller raw_spin_unlock_irqrestore(&console_write_lock, flags);
58595a251cSDavid S. Miller }
59efe6c3ddSRobert Reif
prom_printf(const char * fmt,...)60bd4352caSDavid S. Miller void notrace prom_printf(const char *fmt, ...)
61efe6c3ddSRobert Reif {
62efe6c3ddSRobert Reif va_list args;
63efe6c3ddSRobert Reif int i;
64efe6c3ddSRobert Reif
65efe6c3ddSRobert Reif va_start(args, fmt);
66efe6c3ddSRobert Reif i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
67efe6c3ddSRobert Reif va_end(args);
68efe6c3ddSRobert Reif
69efe6c3ddSRobert Reif prom_write(ppbuf, i);
70efe6c3ddSRobert Reif }
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