forked from Archive/PX4-Autopilot
131 lines
3.9 KiB
C
131 lines
3.9 KiB
C
/****************************************************************************
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*
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* Copyright (C) 2012 PX4 Development Team. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/*
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* High-resolution timer callouts and timekeeping.
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*/
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#ifndef UP_HRT_H_
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#define UP_HRT_H_
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#include <sys/types.h>
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#include <stdbool.h>
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#include <time.h>
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#include <queue.h>
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/*
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* Absolute time, in microsecond units.
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*
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* Absolute time is measured from some arbitrary epoch shortly after
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* system startup. It should never wrap or go backwards.
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*/
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typedef uint64_t hrt_abstime;
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/*
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* Callout function type.
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*
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* Note that callouts run in the timer interrupt context, so
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* they are serialised with respect to each other, and must not
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* block.
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*/
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typedef void (* hrt_callout)(void *arg);
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/*
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* Callout record.
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*/
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typedef struct hrt_call {
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struct sq_entry_s link;
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hrt_abstime deadline;
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hrt_abstime period;
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hrt_callout callout;
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void *arg;
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} *hrt_call_t;
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/*
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* Get absolute time.
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*/
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extern hrt_abstime hrt_absolute_time(void);
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/*
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* Convert a timespec to absolute time.
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*/
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extern hrt_abstime ts_to_abstime(struct timespec *ts);
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/*
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* Convert absolute time to a timespec.
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*/
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extern void abstime_to_ts(struct timespec *ts, hrt_abstime abstime);
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/*
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* Call callout(arg) after delay has elapsed.
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*
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* If callout is NULL, this can be used to implement a timeout by testing the call
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* with hrt_called().
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*/
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extern void hrt_call_after(struct hrt_call *entry, hrt_abstime delay, hrt_callout callout, void *arg);
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/*
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* Call callout(arg) at absolute time calltime.
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*/
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extern void hrt_call_at(struct hrt_call *entry, hrt_abstime calltime, hrt_callout callout, void *arg);
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/*
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* Call callout(arg) after delay, and then after every interval.
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*
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* Note thet the interval is timed between scheduled, not actual, call times, so the call rate may
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* jitter but should not drift.
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*/
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extern void hrt_call_every(struct hrt_call *entry, hrt_abstime delay, hrt_abstime interval, hrt_callout callout, void *arg);
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/*
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* If this returns true, the entry has been invoked and removed from the callout list,
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* or it has never been entered.
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*
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* Always returns false for repeating callouts.
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*/
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extern bool hrt_called(struct hrt_call *entry);
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/*
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* Remove the entry from the callout list.
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*/
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extern void hrt_cancel(struct hrt_call *entry);
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/*
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* Initialise the HRT.
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*/
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extern void hrt_init(void);
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#endif /* UP_HRT_H_ */
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