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/* SPDX-License-Identifier: GPL-3.0-or-later */
/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
#ifndef APOS_TIMER_H
#define APOS_TIMER_H
/**
* @file timer.h
* Timer handling.
*
* \todo Document exceptions and return values better.
*/
#include <apos/types.h>
/**
* ticks_t typedef, use unsigned 64bit integer on all platforms.
*
* GCC will compile uint64_t even on 32bit platforms, just with some runtime
* overhead, should be fine. This will allow us to have a reasonable time range
* even with nanosecond clocks. (138 years with ~4.2 Hz clock)
*/
typedef uint64_t ticks_t;
/**
* tunit_t typedef, whichever time unit we're dealing with.
*/
typedef size_t tunit_t;
/**
* Timer structure.
*/
struct timer {
/** tid. Thread ID of whoever scheduled the timer. */
id_t tid;
/** cid. Control ID, used to differentiate timers. */
id_t cid;
/** ticks. Absolute number of ticks, essentially a timepoint for when
* the timer should trigger. */
ticks_t ticks;
};
/**
* Initialize timers.
*
* @param fdt Pointer to global FDT
*/
void init_timer(const void *fdt);
/**
* Set up timer interrupt ticks from now.
*
* @param tid Thread id for callback.
* @param ticks Ticks from \ref current_ticks().
* @return Id of created timer.
*/
id_t new_rel_timer(id_t tid, ticks_t ticks);
/**
* Set up timer interrupt at ticks.
*
* @param tid Thread id for callback.
* @param ticks Ticks from \ref current_ticks().
* @return Id of created timer.
*/
id_t new_abs_timer(id_t tid, ticks_t ticks);
/**
* Return a pointer to the newest timer, i.e. the one that is closest to
* triggering.
*
* @return Pointer to a timer or NULL if queue is empty.
*/
struct timer *newest_timer();
/**
* Find a timer associated with a specific control ID.
*
* @param cid Control ID to find.
* @return Pointer to associated timer if found, else NULL.
*/
struct timer *find_timer(id_t cid);
/**
* Remove a timer.
*
* @param timer Pointer to timer to remove.
* @return OK on success.
*/
stat_t remove_timer(struct timer *timer);
/**
* Convert nanoseconds to ticks.
*
* @param nsecs Number of nanoseconds to represent as ticks.
* @return Equivalent ticks to nsecs.
*/
ticks_t nsecs_to_ticks(tunit_t nsecs);
/**
* Convert microseconds to ticks.
*
* @param usecs Number of microseconds to represent as ticks.
* @return Equivalent ticks to usecs.
*/
static inline ticks_t usecs_to_ticks(tunit_t usecs)
{
return nsecs_to_ticks(usecs * 1000);
}
/**
* Convert milliseconds to ticks.
*
* @param msecs Number of milliseconds to represent as ticks.
* @return Equivalent ticks to msecs.
*/
static inline ticks_t msecs_to_ticks(tunit_t msecs)
{
return usecs_to_ticks(msecs * 1000);
}
/**
* Convert seconds to ticks.
*
* @param secs Number of seconds to represent as ticks.
* @return Equivalent ticks to secs.
*/
static inline ticks_t secs_to_ticks(tunit_t secs)
{
/** \todo likely not a problem on 64bit systems, not sure how to handle situation on
* 32bit */
return msecs_to_ticks(secs * 1000);
}
#endif /* APOS_TIMER_H */
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