1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * printf.c: Internal prom library printf facility. |
4 | * |
5 | * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) |
6 | * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) |
7 | * Copyright (c) 2002 Pete Zaitcev (zaitcev@yahoo.com) |
8 | * |
9 | * We used to warn all over the code: DO NOT USE prom_printf(), |
10 | * and yet people do. Anton's banking code was outputting banks |
11 | * with prom_printf for most of the 2.4 lifetime. Since an effective |
12 | * stick is not available, we deployed a carrot: an early printk |
13 | * through PROM by means of -p boot option. This ought to fix it. |
14 | * USE printk; if you need, deploy -p. |
15 | */ |
16 | |
17 | #include <linux/kernel.h> |
18 | #include <linux/compiler.h> |
19 | #include <linux/spinlock.h> |
20 | |
21 | #include <asm/openprom.h> |
22 | #include <asm/oplib.h> |
23 | |
24 | #define CONSOLE_WRITE_BUF_SIZE 1024 |
25 | |
26 | static char ppbuf[1024]; |
27 | static char console_write_buf[CONSOLE_WRITE_BUF_SIZE]; |
28 | static DEFINE_RAW_SPINLOCK(console_write_lock); |
29 | |
30 | void notrace prom_write(const char *buf, unsigned int n) |
31 | { |
32 | unsigned int dest_len; |
33 | unsigned long flags; |
34 | char *dest; |
35 | |
36 | dest = console_write_buf; |
37 | raw_spin_lock_irqsave(&console_write_lock, flags); |
38 | |
39 | dest_len = 0; |
40 | while (n-- != 0) { |
41 | char ch = *buf++; |
42 | if (ch == '\n') { |
43 | *dest++ = '\r'; |
44 | dest_len++; |
45 | } |
46 | *dest++ = ch; |
47 | dest_len++; |
48 | if (dest_len >= CONSOLE_WRITE_BUF_SIZE - 1) { |
49 | prom_console_write_buf(console_write_buf, dest_len); |
50 | dest = console_write_buf; |
51 | dest_len = 0; |
52 | } |
53 | } |
54 | if (dest_len) |
55 | prom_console_write_buf(console_write_buf, dest_len); |
56 | |
57 | raw_spin_unlock_irqrestore(&console_write_lock, flags); |
58 | } |
59 | |
60 | void notrace prom_printf(const char *fmt, ...) |
61 | { |
62 | va_list args; |
63 | int i; |
64 | |
65 | va_start(args, fmt); |
66 | i = vscnprintf(buf: ppbuf, size: sizeof(ppbuf), fmt, args); |
67 | va_end(args); |
68 | |
69 | prom_write(buf: ppbuf, n: i); |
70 | } |
71 | |