POSIX: added hrt_queue for handling fast periodic events

The workqueues measure time in ticks  which is typically 10ms.
Some interrupt events in Nuttx occur at about 1ms so a more
granular workqueue is needed for POSIX.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/platforms/posix/px4_layer/hrt_queue.c

@@ -49,8 +49,6 @@
 #include <px4_workqueue.h>
 #include "hrt_work.h"
 
-#ifdef CONFIG_SCHED_WORKQUEUE
-
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -129,4 +127,3 @@ int hrt_work_queue(struct work_s *work, worker_t worker, void *arg, uint32_t del
   return PX4_OK;
 }
 
-#endif /* CONFIG_SCHED_WORKQUEUE */

src/platforms/posix/px4_layer/hrt_work_lock.h

@@ -0,0 +1,54 @@
+/****************************************************************************
+ *
+ * Copyright (C) 2015 Mark Charlebois. 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.
+ *
+ ****************************************************************************/
+
+#include <px4_log.h>
+#include <semaphore.h>
+#include <stdio.h>
+
+#pragma once
+extern sem_t _hrt_work_lock;
+
+inline void hrt_work_lock();
+inline void hrt_work_lock()
+{
+	PX4_INFO("hrt_work_lock");
+	sem_wait(&_hrt_work_lock);
+}
+
+inline void hrt_work_unlock();
+inline void hrt_work_unlock()
+{
+	PX4_INFO("hrt_work_unlock");
+	sem_post(&_hrt_work_lock);
+}
+