include/time.h

   1 /*
   2  * SPDX-License-Identifier:     GPL-2.0+
   3  */
   4
   5 #ifndef _TIME_H
   6 #define _TIME_H
   7
   8 #include <linux/typecheck.h>
   9
  10 unsigned long get_timer(unsigned long base);
  11
  12 /*
  13  * Return the current value of a monotonically increasing microsecond timer.
  14  * Granularity may be larger than 1us if hardware does not support this.
  15  */
  16 unsigned long timer_get_us(void);
  17
  18 /*
  19  *      These inlines deal with timer wrapping correctly. You are
  20  *      strongly encouraged to use them
  21  *      1. Because people otherwise forget
  22  *      2. Because if the timer wrap changes in future you won't have to
  23  *         alter your driver code.
  24  *
  25  * time_after(a,b) returns true if the time a is after time b.
  26  *
  27  * Do this with "<0" and ">=0" to only test the sign of the result. A
  28  * good compiler would generate better code (and a really good compiler
  29  * wouldn't care). Gcc is currently neither.
  30  */
  31 #define time_after(a,b)         \
  32         (typecheck(unsigned long, a) && \
  33          typecheck(unsigned long, b) && \
  34          ((long)((b) - (a)) < 0))
  35 #define time_before(a,b)        time_after(b,a)
  36
  37 #define time_after_eq(a,b)      \
  38         (typecheck(unsigned long, a) && \
  39          typecheck(unsigned long, b) && \
  40          ((long)((a) - (b)) >= 0))
  41 #define time_before_eq(a,b)     time_after_eq(b,a)
  42
  43 /*
  44  * Calculate whether a is in the range of [b, c].
  45  */
  46 #define time_in_range(a,b,c) \
  47         (time_after_eq(a,b) && \
  48          time_before_eq(a,c))
  49
  50 /*
  51  * Calculate whether a is in the range of [b, c).
  52  */
  53 #define time_in_range_open(a,b,c) \
  54         (time_after_eq(a,b) && \
  55          time_before(a,c))
  56
  57 #endif /* _TIME_H */