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/* libhw/generic/alarmclock.h - Device-independent alarmclock definitions
*
* Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#ifndef _LIBHW_GENERIC_ALARMCLOCK_H_
#define _LIBHW_GENERIC_ALARMCLOCK_H_
#include <stdbool.h> /* for bool */
#include <stdint.h> /* for uint{n}_t and UINT{n}_C */
#include <libmisc/private.h>
#include <libmisc/vcall.h>
/* Useful constants ***********************************************************/
#define NS_PER_S UINT64_C(1000000000) /* needs at least log₂(10⁹) ≈ 29.9 bits */
#define US_PER_S UINT64_C(1000000) /* needs at least log₂(10⁶) ≈ 19.9 bits */
#define MS_PER_S UINT64_C(1000) /* needs at least log₂(10³) ≈ 9.9 bits */
/* Structs ********************************************************************/
struct alarmclock_trigger;
struct alarmclock_trigger {
BEGIN_PRIVATE(LIBHW_GENERIC_ALARMCLOCK_H)
void *alarmclock;
struct alarmclock_trigger *prev, *next;
uint64_t fire_at_ns;
void (*cb)(void *);
void *cb_arg;
END_PRIVATE(LIBHW_GENERIC_ALARMCLOCK_H)
};
/* Interface ******************************************************************/
struct alarmclock_vtable;
typedef struct {
struct alarmclock_vtable *vtable;
} implements_alarmclock;
struct alarmclock_vtable {
/**
* (2⁶⁴-1 nanoseconds is more than 500 years; there is little
* risk of this overflowing)
*/
uint64_t (*get_time_ns)(implements_alarmclock *self);
/**
* Returns true on error.
*
* Implementations may return an error if fire_at_ns is more
* than UINT32_MAX µs (72 minutes) in the future.
*
* If fire_at_ns is in the past, then it will fire
* immediately.
*/
bool (*add_trigger)(implements_alarmclock *self, struct alarmclock_trigger *trigger,
uint64_t fire_at_ns,
void (*cb)(void *),
void *cb_arg);
void (*del_trigger)(implements_alarmclock *self, struct alarmclock_trigger *trigger);
};
/* Utilities ******************************************************************/
void alarmclock_sleep_until_ns(implements_alarmclock *clock, uint64_t abstime_ns);
static inline void alarmclock_sleep_for_ns(implements_alarmclock *clock, uint64_t delta_ns) {
alarmclock_sleep_until_ns(clock, VCALL(clock, get_time_ns) + delta_ns);
}
static inline void alarmclock_sleep_for_us(implements_alarmclock *clock, uint64_t delta_us) {
alarmclock_sleep_for_ns(clock, delta_us * (NS_PER_S/US_PER_S));
}
static inline void alarmclock_sleep_for_ms(implements_alarmclock *clock, uint64_t delta_ms) {
alarmclock_sleep_for_ns(clock, delta_ms * (NS_PER_S/MS_PER_S));
}
static inline void alarmclock_sleep_for_s(implements_alarmclock *clock, uint64_t delta_s) {
alarmclock_sleep_for_ns(clock, delta_s * NS_PER_S);
}
/* Globals ********************************************************************/
extern implements_alarmclock *bootclock;
#define sleep_until_ns(t) alarmclock_sleep_until_ns(bootclock, t)
#define sleep_for_ns(t) alarmclock_sleep_for_ns(bootclock, t)
#define sleep_for_us(t) alarmclock_sleep_for_us(bootclock, t)
#define sleep_for_ms(t) alarmclock_sleep_for_ms(bootclock, t)
#define sleep_for_s(t) alarmclock_sleep_for_s(bootclock, t)
#endif /* _LIBHW_GENERIC_ALARMCLOCK_H_ */
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