include/time.h

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