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 } 70