diff options
Diffstat (limited to 'src/include/timer.h')
| -rw-r--r-- | src/include/timer.h | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/include/timer.h b/src/include/timer.h index 49eae5ec40..d3afb19646 100644 --- a/src/include/timer.h +++ b/src/include/timer.h @@ -15,6 +15,8 @@ #ifndef TIMER_H #define TIMER_H +#include <types.h> + #define NSECS_PER_SEC 1000000000 #define USECS_PER_SEC 1000000 #define MSECS_PER_SEC 1000 @@ -195,4 +197,36 @@ static inline long stopwatch_duration_msecs(struct stopwatch *sw) return stopwatch_duration_usecs(sw) / USECS_PER_MSEC; } +/* + * Helper macro to wait until a condition becomes true or a timeout elapses. + * + * condition: a C expression to wait for + * timeout: timeout, in microseconds + * + * Returns: + * 0 if the condition still evaluates to false after the timeout elapsed, + * >0 if the condition evaluates to true. The return value is the amount of + * microseconds waited (at least 1). + */ +#define wait_us(timeout_us, condition) \ +({ \ + long __ret = 0; \ + struct stopwatch __sw; \ + stopwatch_init_usecs_expire(&__sw, timeout_us); \ + do { \ + if (condition) { \ + stopwatch_tick(&__sw); \ + __ret = stopwatch_duration_usecs(&__sw); \ + if (!__ret) /* make sure it evaluates to true */\ + __ret = 1; \ + break; \ + } \ + } while (!stopwatch_expired(&__sw)); \ + __ret; \ +}) + +#define wait_ms(timeout_ms, condition) \ + DIV_ROUND_UP(wait_us((timeout_ms) * USECS_PER_MSEC, condition), \ + USECS_PER_MSEC) + #endif /* TIMER_H */ |