aboutsummaryrefslogtreecommitdiff
path: root/src/drivers/drv_hrt.h
diff options
context:
space:
mode:
authorLorenz Meier <lm@inf.ethz.ch>2013-04-28 09:54:11 +0200
committerLorenz Meier <lm@inf.ethz.ch>2013-04-28 09:54:11 +0200
commit13fc6703862862f4263d8d5d085b7a16b87190e1 (patch)
tree47f3a17cb6f38b1aafe22e1cdef085cd73cd3a1d /src/drivers/drv_hrt.h
parentf57439b90e23de260259dec051d3e2ead2d61c8c (diff)
downloadpx4-firmware-13fc6703862862f4263d8d5d085b7a16b87190e1.tar.gz
px4-firmware-13fc6703862862f4263d8d5d085b7a16b87190e1.tar.bz2
px4-firmware-13fc6703862862f4263d8d5d085b7a16b87190e1.zip
Moved last libs, drivers and headers, cleaned up IO build
Diffstat (limited to 'src/drivers/drv_hrt.h')
-rw-r--r--src/drivers/drv_hrt.h149
1 files changed, 149 insertions, 0 deletions
diff --git a/src/drivers/drv_hrt.h b/src/drivers/drv_hrt.h
new file mode 100644
index 000000000..8a99eeca7
--- /dev/null
+++ b/src/drivers/drv_hrt.h
@@ -0,0 +1,149 @@
+/****************************************************************************
+ *
+ * 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);
+
+/*
+ * Compute the delta between a timestamp taken in the past
+ * and now.
+ *
+ * This function is safe to use even if the timestamp is updated
+ * by an interrupt during execution.
+ */
+__EXPORT extern hrt_abstime hrt_elapsed_time(const volatile hrt_abstime *then);
+
+/*
+ * Store the absolute time in an interrupt-safe fashion.
+ *
+ * This function ensures that the timestamp cannot be seen half-written by an interrupt handler.
+ */
+__EXPORT extern hrt_abstime hrt_store_absolute_time(volatile hrt_abstime *now);
+
+/*
+ * 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