Linux kernel mirror (for testing)
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1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 by Waldorf Electronics
7 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2007 Maciej W. Rozycki
10 */
11#include <linux/module.h>
12#include <linux/param.h>
13#include <linux/smp.h>
14
15#include <asm/compiler.h>
16#include <asm/war.h>
17
18inline void __delay(unsigned int loops)
19{
20 __asm__ __volatile__ (
21 " .set noreorder \n"
22 " .align 3 \n"
23 "1: bnez %0, 1b \n"
24 " subu %0, 1 \n"
25 " .set reorder \n"
26 : "=r" (loops)
27 : "0" (loops));
28}
29EXPORT_SYMBOL(__delay);
30
31/*
32 * Division by multiplication: you don't have to worry about
33 * loss of precision.
34 *
35 * Use only for very small delays ( < 1 msec). Should probably use a
36 * lookup table, really, as the multiplications take much too long with
37 * short delays. This is a "reasonable" implementation, though (and the
38 * first constant multiplications gets optimized away if the delay is
39 * a constant)
40 */
41
42void __udelay(unsigned long us)
43{
44 unsigned int lpj = raw_current_cpu_data.udelay_val;
45
46 __delay((us * 0x000010c7ull * HZ * lpj) >> 32);
47}
48EXPORT_SYMBOL(__udelay);
49
50void __ndelay(unsigned long ns)
51{
52 unsigned int lpj = raw_current_cpu_data.udelay_val;
53
54 __delay((ns * 0x00000005ull * HZ * lpj) >> 32);
55}
56EXPORT_SYMBOL(__ndelay);