Kernel  |  3.3

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C++程序  |  56行  |  1.39 KB
#ifndef _LINUX_DELAY_H
#define _LINUX_DELAY_H

 * Copyright (C) 1993 Linus Torvalds
 * Delay routines, using a pre-computed "loops_per_jiffy" value.

#include <linux/kernel.h>

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.

#define MAX_UDELAY_MS	5

#ifndef mdelay
#define mdelay(n) (\
	(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
	({unsigned long __ms=(n); while (__ms--) udelay(1000);}))

#ifndef ndelay
static inline void ndelay(unsigned long x)
	udelay(DIV_ROUND_UP(x, 1000));
#define ndelay(x) ndelay(x)

extern unsigned long lpj_fine;
void calibrate_delay(void);
void msleep(unsigned int msecs);
unsigned long msleep_interruptible(unsigned int msecs);
void usleep_range(unsigned long min, unsigned long max);

static inline void ssleep(unsigned int seconds)
	msleep(seconds * 1000);

#endif /* defined(_LINUX_DELAY_H) */