diff options
Diffstat (limited to 'include/time.h')
-rw-r--r-- | include/time.h | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/include/time.h b/include/time.h new file mode 100644 index 0000000..5746ad9 --- /dev/null +++ b/include/time.h @@ -0,0 +1,57 @@ +/* + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef _TIME_H +#define _TIME_H + +#include <linux/typecheck.h> + +unsigned long get_timer(unsigned long base); + +/* + * Return the current value of a monotonically increasing microsecond timer. + * Granularity may be larger than 1us if hardware does not support this. + */ +unsigned long timer_get_us(void); + +/* + * These inlines deal with timer wrapping correctly. You are + * strongly encouraged to use them + * 1. Because people otherwise forget + * 2. Because if the timer wrap changes in future you won't have to + * alter your driver code. + * + * time_after(a,b) returns true if the time a is after time b. + * + * Do this with "<0" and ">=0" to only test the sign of the result. A + * good compiler would generate better code (and a really good compiler + * wouldn't care). Gcc is currently neither. + */ +#define time_after(a,b) \ + (typecheck(unsigned long, a) && \ + typecheck(unsigned long, b) && \ + ((long)((b) - (a)) < 0)) +#define time_before(a,b) time_after(b,a) + +#define time_after_eq(a,b) \ + (typecheck(unsigned long, a) && \ + typecheck(unsigned long, b) && \ + ((long)((a) - (b)) >= 0)) +#define time_before_eq(a,b) time_after_eq(b,a) + +/* + * Calculate whether a is in the range of [b, c]. + */ +#define time_in_range(a,b,c) \ + (time_after_eq(a,b) && \ + time_before_eq(a,c)) + +/* + * Calculate whether a is in the range of [b, c). + */ +#define time_in_range_open(a,b,c) \ + (time_after_eq(a,b) && \ + time_before(a,c)) + +#endif /* _TIME_H */ |