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

   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
  26static char ppbuf[1024];
  27static char console_write_buf[CONSOLE_WRITE_BUF_SIZE];
  28static DEFINE_RAW_SPINLOCK(console_write_lock);
  29
  30void 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
  60void notrace prom_printf(const char *fmt, ...)
  61{
  62        va_list args;
  63        int i;
  64
  65        va_start(args, fmt);
  66        i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
  67        va_end(args);
  68
  69        prom_write(ppbuf, i);
  70}
  71