LXR linux/include/linux/delay.h

   1#ifndef _LINUX_DELAY_H
   2#define _LINUX_DELAY_H
   3
   4/*
   5 * Copyright (C) 1993 Linus Torvalds
   6 *
   7 * Delay routines, using a pre-computed "loops_per_jiffy" value.
   8 */
   9
  10extern unsigned long loops_per_jiffy;
  11
  12#include <asm/delay.h>
  13
  14/*
  15 * Using udelay() for intervals greater than a few milliseconds can
  16 * risk overflow for high loops_per_jiffy (high bogomips) machines. The
  17 * mdelay() provides a wrapper to prevent this.  For delays greater
  18 * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
  19 * specific values can be defined in asm-???/delay.h as an override.
  20 * The 2nd mdelay() definition ensures GCC will optimize away the 
  21 * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.
  22 */
  23
  24#ifndef MAX_UDELAY_MS
  25#define MAX_UDELAY_MS   5
  26#endif
  27
  28#ifndef mdelay
  29#define mdelay(n) (\
  30        (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
  31        ({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
  32#endif
  33
  34#ifndef ndelay
  35#define ndelay(x)       udelay(((x)+999)/1000)
  36#endif
  37
  38void calibrate_delay(void);
  39void msleep(unsigned int msecs);
  40unsigned long msleep_interruptible(unsigned int msecs);
  41
  42static inline void ssleep(unsigned int seconds)
  43{
  44        msleep(seconds * 1000);
  45}
  46
  47#endif /* defined(_LINUX_DELAY_H) */
  48