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 #include <linux/types.h>
   8
   9 unsigned long get_timer(unsigned long base);
  10
  11 /*
  12  * Return the current value of a monotonically increasing microsecond timer.
  13  * Granularity may be larger than 1us if hardware does not support this.
  14  */
  15 unsigned long timer_get_us(void);
  16
  17 /*
  18  * timer_test_add_offset()
  19  *
  20  * Allow tests to add to the time reported through lib/time.c functions
  21  * offset: number of milliseconds to advance the system time
  22  */
  23 void timer_test_add_offset(unsigned long offset);
  24
  25 /**
  26  * usec_to_tick() - convert microseconds to clock ticks
  27  *
  28  * @usec:       duration in microseconds
  29  * Return:      duration in clock ticks
  30  */
  31 uint64_t usec_to_tick(unsigned long usec);
  32
  33 /*
  34  *      These inlines deal with timer wrapping correctly. You are
  35  *      strongly encouraged to use them
  36  *      1. Because people otherwise forget
  37  *      2. Because if the timer wrap changes in future you won't have to
  38  *         alter your driver code.
  39  *
  40  * time_after(a,b) returns true if the time a is after time b.
  41  *
  42  * Do this with "<0" and ">=0" to only test the sign of the result. A
  43  * good compiler would generate better code (and a really good compiler
  44  * wouldn't care). Gcc is currently neither.
  45  */
  46 #define time_after(a,b)         \
  47         (typecheck(unsigned long, a) && \
  48          typecheck(unsigned long, b) && \
  49          ((long)((b) - (a)) < 0))
  50 #define time_before(a,b)        time_after(b,a)
  51
  52 #define time_after_eq(a,b)      \
  53         (typecheck(unsigned long, a) && \
  54          typecheck(unsigned long, b) && \
  55          ((long)((a) - (b)) >= 0))
  56 #define time_before_eq(a,b)     time_after_eq(b,a)
  57
  58 /*
  59  * Calculate whether a is in the range of [b, c].
  60  */
  61 #define time_in_range(a,b,c) \
  62         (time_after_eq(a,b) && \
  63          time_before_eq(a,c))
  64
  65 /*
  66  * Calculate whether a is in the range of [b, c).
  67  */
  68 #define time_in_range_open(a,b,c) \
  69         (time_after_eq(a,b) && \
  70          time_before(a,c))
  71
  72 #endif /* _TIME_H */