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
  25 static char ppbuf[1024];
  26 static char console_write_buf[CONSOLE_WRITE_BUF_SIZE];
  27 static DEFINE_RAW_SPINLOCK(console_write_lock);
  28
  29 void 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
  59 void 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 }