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
  10 #include <linux/kernel.h>
  11
  12 extern unsigned long loops_per_jiffy;
  13
  14 #include <asm/delay.h>
  15
  16 /*
  17  * Using udelay() for intervals greater than a few milliseconds can
  18  * risk overflow for high loops_per_jiffy (high bogomips) machines. The
  19  * mdelay() provides a wrapper to prevent this.  For delays greater
  20  * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
  21  * specific values can be defined in asm-???/delay.h as an override.
  22  * The 2nd mdelay() definition ensures GCC will optimize away the
  23  * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.
  24  */
  25
  26 #ifndef MAX_UDELAY_MS
  27 #define MAX_UDELAY_MS   5
  28 #endif
  29
  30 #ifndef mdelay
  31 #define mdelay(n) (\
  32         (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
  33         ({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
  34 #endif
  35
  36 #ifndef ndelay
  37 static inline void ndelay(unsigned long x)
  38 {
  39         udelay(DIV_ROUND_UP(x, 1000));
  40 }
  41 #define ndelay(x) ndelay(x)
  42 #endif
  43
  44 void calibrate_delay(void);
  45 void msleep(unsigned int msecs);
  46 unsigned long msleep_interruptible(unsigned int msecs);
  47
  48 static inline void ssleep(unsigned int seconds)
  49 {
  50         msleep(seconds * 1000);
  51 }
  52
  53 #endif /* defined(_LINUX_DELAY_H) */