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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* delay.h: FRV delay code
2 *
3 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#ifndef _ASM_DELAY_H
13#define _ASM_DELAY_H
14
15#include <asm/param.h>
16#include <asm/timer-regs.h>
17
18/*
19 * delay loop - runs at __core_clock_speed_HZ / 2 [there are 2 insns in the loop]
20 */
21extern unsigned long __delay_loops_MHz;
22
23static inline void __delay(unsigned long loops)
24{
25 asm volatile("1: subicc %0,#1,%0,icc0 \n"
26 " bnc icc0,#2,1b \n"
27 : "=r" (loops)
28 : "0" (loops)
29 : "icc0"
30 );
31}
32
33/*
34 * Use only for very small delays ( < 1 msec). Should probably use a
35 * lookup table, really, as the multiplications take much too long with
36 * short delays. This is a "reasonable" implementation, though (and the
37 * first constant multiplications gets optimized away if the delay is
38 * a constant)
39 */
40
41extern unsigned long loops_per_jiffy;
42
43static inline void udelay(unsigned long usecs)
44{
45 __delay(usecs * __delay_loops_MHz);
46}
47
48#define ndelay(n) udelay((n) * 5)
49
50#endif /* _ASM_DELAY_H */