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149 lines
4.5 KiB
149 lines
4.5 KiB
/**************************************************************************** |
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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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* @file drv_hrt.h |
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* |
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* High-resolution timer with callouts and timekeeping. |
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*/ |
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#pragma once |
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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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__BEGIN_DECLS |
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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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__EXPORT 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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__EXPORT 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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__EXPORT extern void abstime_to_ts(struct timespec *ts, hrt_abstime abstime); |
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/* |
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* Compute the delta between a timestamp taken in the past |
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* and now. |
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* |
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* This function is safe to use even if the timestamp is updated |
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* by an interrupt during execution. |
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*/ |
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__EXPORT extern hrt_abstime hrt_elapsed_time(const volatile hrt_abstime *then); |
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/* |
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* Store the absolute time in an interrupt-safe fashion. |
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* |
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* This function ensures that the timestamp cannot be seen half-written by an interrupt handler. |
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*/ |
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__EXPORT extern hrt_abstime hrt_store_absolute_time(volatile hrt_abstime *now); |
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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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__EXPORT 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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__EXPORT 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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__EXPORT 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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__EXPORT 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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__EXPORT 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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__EXPORT extern void hrt_init(void); |
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__END_DECLS
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