File: [Development] / linux-2.6-xfs / include / asm-arm / Attic / delay.h (download)
Revision 1.3, Mon May 29 16:35:25 2006 UTC (11 years, 4 months ago) by nathans.longdrop.melbourne.sgi.com
Branch: MAIN
Changes since 1.2: +7 -5
lines
Merge up to 2.6.17-rc5.
Merge of 2.6.x-xfs-melb:linux:26065a by kenmcd.
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/*
* Copyright (C) 1995-2004 Russell King
*
* Delay routines, using a pre-computed "loops_per_second" value.
*/
#ifndef __ASM_ARM_DELAY_H
#define __ASM_ARM_DELAY_H
#include <asm/param.h> /* HZ */
extern void __delay(int loops);
/*
* This function intentionally does not exist; if you see references to
* it, it means that you're calling udelay() with an out of range value.
*
* With currently imposed limits, this means that we support a max delay
* of 2000us. Further limits: HZ<=1000 and bogomips<=3355
*/
extern void __bad_udelay(void);
/*
* division by multiplication: you don't have to worry about
* loss of precision.
*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
extern void __udelay(unsigned long usecs);
extern void __const_udelay(unsigned long);
#define MAX_UDELAY_MS 2
#define udelay(n) \
(__builtin_constant_p(n) ? \
((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \
__const_udelay((n) * ((2199023U*HZ)>>11))) : \
__udelay(n))
#endif /* defined(_ARM_DELAY_H) */