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authorpx4dev <px4@purgatory.org>2012-10-23 18:02:36 -0700
committerpx4dev <px4@purgatory.org>2012-10-23 23:51:12 -0700
commitc3fe915b44a1b32f05b182b3079c722b82b20fb9 (patch)
treeacde0f2c5c64e4c22afdd810c10cdfe7fdc11c5b /apps/drivers/drv_hrt.h
parent1b3ab2f18df9b442a01d1093af952e44823c3c9d (diff)
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Checkpoint - moving things out of the NuttX configs/*/src directories
Diffstat (limited to 'apps/drivers/drv_hrt.h')
-rw-r--r--apps/drivers/drv_hrt.h133
1 files changed, 133 insertions, 0 deletions
diff --git a/apps/drivers/drv_hrt.h b/apps/drivers/drv_hrt.h
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+/****************************************************************************
+ *
+ * Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file drv_hrt.h
+ *
+ * High-resolution timer with callouts and timekeeping.
+ */
+
+#pragma once
+
+#include <sys/types.h>
+#include <stdbool.h>
+
+#include <time.h>
+#include <queue.h>
+
+__BEGIN_DECLS
+
+/*
+ * Absolute time, in microsecond units.
+ *
+ * Absolute time is measured from some arbitrary epoch shortly after
+ * system startup. It should never wrap or go backwards.
+ */
+typedef uint64_t hrt_abstime;
+
+/*
+ * Callout function type.
+ *
+ * Note that callouts run in the timer interrupt context, so
+ * they are serialised with respect to each other, and must not
+ * block.
+ */
+typedef void (* hrt_callout)(void *arg);
+
+/*
+ * Callout record.
+ */
+typedef struct hrt_call {
+ struct sq_entry_s link;
+
+ hrt_abstime deadline;
+ hrt_abstime period;
+ hrt_callout callout;
+ void *arg;
+} *hrt_call_t;
+
+/*
+ * Get absolute time.
+ */
+__EXPORT extern hrt_abstime hrt_absolute_time(void);
+
+/*
+ * Convert a timespec to absolute time.
+ */
+__EXPORT extern hrt_abstime ts_to_abstime(struct timespec *ts);
+
+/*
+ * Convert absolute time to a timespec.
+ */
+__EXPORT extern void abstime_to_ts(struct timespec *ts, hrt_abstime abstime);
+
+/*
+ * Call callout(arg) after delay has elapsed.
+ *
+ * If callout is NULL, this can be used to implement a timeout by testing the call
+ * with hrt_called().
+ */
+__EXPORT extern void hrt_call_after(struct hrt_call *entry, hrt_abstime delay, hrt_callout callout, void *arg);
+
+/*
+ * Call callout(arg) at absolute time calltime.
+ */
+__EXPORT extern void hrt_call_at(struct hrt_call *entry, hrt_abstime calltime, hrt_callout callout, void *arg);
+
+/*
+ * Call callout(arg) after delay, and then after every interval.
+ *
+ * Note thet the interval is timed between scheduled, not actual, call times, so the call rate may
+ * jitter but should not drift.
+ */
+__EXPORT extern void hrt_call_every(struct hrt_call *entry, hrt_abstime delay, hrt_abstime interval, hrt_callout callout, void *arg);
+
+/*
+ * If this returns true, the entry has been invoked and removed from the callout list,
+ * or it has never been entered.
+ *
+ * Always returns false for repeating callouts.
+ */
+__EXPORT extern bool hrt_called(struct hrt_call *entry);
+
+/*
+ * Remove the entry from the callout list.
+ */
+__EXPORT extern void hrt_cancel(struct hrt_call *entry);
+
+/*
+ * Initialise the HRT.
+ */
+__EXPORT extern void hrt_init(void);
+
+__END_DECLS