LXR linux/arch/sparc/prom/printf.c

   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#include <linux/spinlock.h>
  19
  20#include <asm/openprom.h>
  21#include <asm/oplib.h>
  22
  23#define CONSOLE_WRITE_BUF_SIZE  1024
  24
  25static char ppbuf[1024];
  26static char console_write_buf[CONSOLE_WRITE_BUF_SIZE];
  27static DEFINE_RAW_SPINLOCK(console_write_lock);
  28
  29void notrace prom_write(const char *buf, unsigned int n)
  30{
  31        unsigned int dest_len;
  32        unsigned long flags;
  33        char *dest;
  34
  35        dest = console_write_buf;
  36        raw_spin_lock_irqsave(&console_write_lock, flags);
  37
  38        dest_len = 0;
  39        while (n-- != 0) {
  40                char ch = *buf++;
  41                if (ch == '\n') {
  42                        *dest++ = '\r';
  43                        dest_len++;
  44                }
  45                *dest++ = ch;
  46                dest_len++;
  47                if (dest_len >= CONSOLE_WRITE_BUF_SIZE - 1) {
  48                        prom_console_write_buf(console_write_buf, dest_len);
  49                        dest = console_write_buf;
  50                        dest_len = 0;
  51                }
  52        }
  53        if (dest_len)
  54                prom_console_write_buf(console_write_buf, dest_len);
  55
  56        raw_spin_unlock_irqrestore(&console_write_lock, flags);
  57}
  58
  59void notrace prom_printf(const char *fmt, ...)
  60{
  61        va_list args;
  62        int i;
  63
  64        va_start(args, fmt);
  65        i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
  66        va_end(args);
  67
  68        prom_write(ppbuf, i);
  69}
  70