printf.c
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/*
* printf.c: Internal prom library printf facility.
*
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
* Copyright (c) 2002 Pete Zaitcev (zaitcev@yahoo.com)
*
* We used to warn all over the code: DO NOT USE prom_printf(),
* and yet people do. Anton's banking code was outputting banks
* with prom_printf for most of the 2.4 lifetime. Since an effective
* stick is not available, we deployed a carrot: an early printk
* through PROM by means of -p boot option. This ought to fix it.
* USE printk; if you need, deploy -p.
*/
#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#define CONSOLE_WRITE_BUF_SIZE 1024
static char ppbuf[1024];
static char console_write_buf[CONSOLE_WRITE_BUF_SIZE];
static DEFINE_RAW_SPINLOCK(console_write_lock);
void notrace prom_write(const char *buf, unsigned int n)
{
unsigned int dest_len;
unsigned long flags;
char *dest;
dest = console_write_buf;
raw_spin_lock_irqsave(&console_write_lock, flags);
dest_len = 0;
while (n-- != 0) {
char ch = *buf++;
if (ch == '\n') {
*dest++ = '\r';
dest_len++;
}
*dest++ = ch;
dest_len++;
if (dest_len >= CONSOLE_WRITE_BUF_SIZE - 1) {
prom_console_write_buf(console_write_buf, dest_len);
dest = console_write_buf;
dest_len = 0;
}
}
if (dest_len)
prom_console_write_buf(console_write_buf, dest_len);
raw_spin_unlock_irqrestore(&console_write_lock, flags);
}
void notrace prom_printf(const char *fmt, ...)
{
va_list args;
int i;
va_start(args, fmt);
i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
va_end(args);
prom_write(ppbuf, i);
}