Move scheduling priorities into px4_tasks to simplify header usage

src/platforms/px4_tasks.h

@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
- *   Author: Lorenz Meier <lm@inf.ethz.ch>
- *   Author: Mark Charlebois <charlebm@gmail.com> 2015
+ *   Copyright (c) 2012-2017 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
@@ -35,6 +33,10 @@
 
 /**
  * @file px4_tasks.h
+ *
+ * @author Lorenz Meier <lorenz@px4.io>
+ * @author Mark Charlebois (2015) <charlebm@gmail.com>
+ *
  * Preserve existing task API call signature with OS abstraction
  */
 
@@ -99,6 +101,53 @@ typedef struct {
 #error "No target OS defined"
 #endif
 
+// Fast drivers - they need to run as quickly as possible to minimize control
+// latency.
+#define SCHED_PRIORITY_FAST_DRIVER		(SCHED_PRIORITY_MAX - 0)
+
+// Attitude controllers typically are in a blocking wait on driver data
+// they should be the first to run on an update, using the current sensor
+// data and the *previous* attitude reference from the position controller
+// which typically runs at a slower rate
+#define SCHED_PRIORITY_ATTITUDE_CONTROL		(SCHED_PRIORITY_MAX - 4)
+
+// Actuator outputs should run before right after the attitude controller
+// updated
+#define SCHED_PRIORITY_ACTUATOR_OUTPUTS		(SCHED_PRIORITY_MAX - 4)
+
+// Position controllers typically are in a blocking wait on estimator data
+// so when new sensor data is available they will run last. Keeping them
+// on a high priority ensures that they are the first process to be run
+// when the estimator updates.
+#define SCHED_PRIORITY_POSITION_CONTROL		(SCHED_PRIORITY_MAX - 5)
+
+// Estimators should run after the attitude controller but before anything
+// else in the system. They wait on sensor data which is either coming
+// from the sensor hub or from a driver. Keeping this class at a higher
+// priority ensures that the estimator runs first if it can, but will
+// wait for the sensor hub if its data is coming from it.
+#define SCHED_PRIORITY_ESTIMATOR		(SCHED_PRIORITY_MAX - 5)
+
+// The sensor hub conditions sensor data. It is not the fastest component
+// in the controller chain, but provides easy-to-use data to the more
+// complex downstream consumers
+#define SCHED_PRIORITY_SENSOR_HUB		(SCHED_PRIORITY_MAX - 6)
+
+// The log capture (which stores log data into RAM) should run faster
+// than other components, but should not run before the control pipeline
+#define SCHED_PRIORITY_LOG_CAPTURE		(SCHED_PRIORITY_MAX - 10)
+
+// Slow drivers should run at a rate where they do not impact the overall
+// system execution
+#define SCHED_PRIORITY_SLOW_DRIVER		(SCHED_PRIORITY_MAX - 35)
+
+// The navigation system needs to execute regularly but has no realtime needs
+#define SCHED_PRIORITY_NAVIGATION		(SCHED_PRIORITY_DEFAULT + 5)
+//      SCHED_PRIORITY_DEFAULT
+#define SCHED_PRIORITY_LOG_WRITER		(SCHED_PRIORITY_DEFAULT - 10)
+#define SCHED_PRIORITY_PARAMS			(SCHED_PRIORITY_DEFAULT - 15)
+//      SCHED_PRIORITY_IDLE
+
 typedef int (*px4_main_t)(int argc, char *argv[]);
 
 __BEGIN_DECLS