|
|
| File: [Development] / linux-2.4-xfs / include / linux / delay.h (download)
Revision 1.1, Wed Dec 31 00:54:49 2003 UTC (13 years, 9 months ago) by cattelan
Initial Import 2.4.24pre2 |
#ifndef _LINUX_DELAY_H
#define _LINUX_DELAY_H
/*
* Copyright (C) 1993 Linus Torvalds
*
* Delay routines, using a pre-computed "loops_per_jiffy" value.
*/
extern unsigned long loops_per_jiffy;
#include <asm/delay.h>
/*
* Using udelay() for intervals greater than a few milliseconds can
* risk overflow for high loops_per_jiffy (high bogomips) machines. The
* mdelay() provides a wrapper to prevent this. For delays greater
* than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture
* specific values can be defined in asm-???/delay.h as an override.
* The 2nd mdelay() definition ensures GCC will optimize away the
* while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G.
*/
#ifndef MAX_UDELAY_MS
#define MAX_UDELAY_MS 5
#endif
#ifdef notdef
#define mdelay(n) (\
{unsigned long msec=(n); while (msec--) udelay(1000);})
#else
#define mdelay(n) (\
(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
({unsigned long msec=(n); while (msec--) udelay(1000);}))
#endif
#endif /* defined(_LINUX_DELAY_H) */