uORB::Subscription minor API cleanup

* the forceInit() method was combined with the existing subscribe()
 * delete unused last_update()

src/modules/commander/Commander.cpp

@@ -4290,7 +4290,7 @@ Commander::offboard_control_update(bool &status_changed)
 
 	if (commander_state_s::MAIN_STATE_OFFBOARD) {
 		if (offboard_control_mode.timestamp == 0) {
-			_offboard_control_mode_sub.forceInit();
+			_offboard_control_mode_sub.subscribe();
 			force_update = true;
 		}
 	}

src/modules/mavlink/mavlink_orb_subscription.cpp

@@ -50,7 +50,7 @@ MavlinkOrbSubscription::is_published()
 	} else if (!published && _subscribe_from_beginning) {
 		// For some topics like vehicle_command_ack, we want to subscribe
 		// from the beginning in order not to miss or delay the first publish respective advertise.
-		return _sub.forceInit();
+		return _sub.subscribe();
 	}
 
 	return false;

src/modules/uORB/Subscription.cpp

@@ -42,36 +42,59 @@
 namespace uORB
 {
 
-bool Subscription::subscribe()
+bool
+Subscription::subscribe()
 {
-	DeviceMaster *device_master = uORB::Manager::get_instance()->get_device_master();
-	_node = device_master->getDeviceNode(_meta, _instance);
+	// valid ORB_ID required
+	if (_meta == nullptr) {
+		return false;
+	}
 
+	// check if already subscribed
 	if (_node != nullptr) {
-		_node->add_internal_subscriber();
-
-		// If there were any previous publications, allow the subscriber to read them
-		const unsigned curr_gen = _node->published_message_count();
-		const unsigned q_size = _node->get_queue_size();
-
-		_last_generation = curr_gen - (q_size < curr_gen ? q_size : curr_gen);
-
 		return true;
 	}
 
+	DeviceMaster *device_master = uORB::Manager::get_instance()->get_device_master();
+
+	if (device_master != nullptr) {
+		uORB::DeviceNode *node = device_master->getDeviceNode(_meta, _instance);
+
+		if (node != nullptr) {
+			_node = node;
+			_node->add_internal_subscriber();
+
+			// If there were any previous publications, allow the subscriber to read them
+			const unsigned curr_gen = _node->published_message_count();
+			const uint8_t q_size = _node->get_queue_size();
+
+			if (q_size < curr_gen) {
+				_last_generation = curr_gen - q_size;
+
+			} else {
+				_last_generation = 0;
+			}
+
+			return true;
+		}
+	}
+
 	return false;
 }
 
-void Subscription::unsubscribe()
+void
+Subscription::unsubscribe()
 {
 	if (_node != nullptr) {
 		_node->remove_internal_subscriber();
 	}
 
+	_node = nullptr;
 	_last_generation = 0;
 }
 
-bool Subscription::init()
+bool
+Subscription::init()
 {
 	if (_meta != nullptr) {
 		// this throttles the relatively expensive calls to getDeviceNode()
@@ -90,18 +113,8 @@ bool Subscription::init()
 	return false;
 }
 
-bool Subscription::forceInit()
-{
-	if (_node == nullptr) {
-		// reset generation to force subscription attempt
-		_last_generation = 0;
-		return subscribe();
-	}
-
-	return false;
-}
-
-bool Subscription::update(uint64_t *time, void *dst)
+bool
+Subscription::update(uint64_t *time, void *dst)
 {
 	if ((time != nullptr) && (dst != nullptr) && published()) {
 		// always copy data to dst regardless of update

src/modules/uORB/Subscription.hpp

@@ -63,13 +63,16 @@ public:
 	 */
 	Subscription(const orb_metadata *meta, uint8_t instance = 0) : _meta(meta), _instance(instance)
 	{
-		init();
+		subscribe();
 	}
 
-	~Subscription() { unsubscribe(); }
+	~Subscription()
+	{
+		unsubscribe();
+	}
 
-	bool init();
-	bool forceInit();
+	bool subscribe();
+	void unsubscribe();
 
 	bool valid() const { return _node != nullptr; }
 	bool published() { return valid() ? _node->is_published() : init(); }
@@ -102,8 +105,6 @@ public:
 	 */
 	bool copy(void *dst) { return published() ? _node->copy(dst, _last_generation) : false; }
 
-	hrt_abstime	last_update() { return published() ? _node->last_update() : 0; }
-
 	uint8_t		get_instance() const { return _instance; }
 	orb_id_t	get_topic() const { return _meta; }
 
@@ -111,10 +112,9 @@ protected:
 
 	friend class SubscriptionCallback;
 
-	DeviceNode	*get_node() { return _node; }
+	DeviceNode		*get_node() { return _node; }
 
-	bool subscribe();
-	void unsubscribe();
+	bool			init();
 
 	DeviceNode		*_node{nullptr};
 	const orb_metadata	*_meta{nullptr};

src/modules/uORB/SubscriptionCallback.hpp

@@ -78,7 +78,7 @@ public:
 			int fd = orb_subscribe_multi(_subscription.get_topic(), _subscription.get_instance());
 
 			// try to register callback again
-			if (_subscription.forceInit()) {
+			if (_subscription.subscribe()) {
 				if (_subscription.get_node() && _subscription.get_node()->register_callback(this)) {
 					ret = true;
 				}
@@ -124,7 +124,7 @@ public:
 	void call() override
 	{
 		// schedule immediately if no interval, otherwise check time elapsed
-		if ((_interval == 0) || (hrt_elapsed_time(&_last_update) >= _interval)) {
+		if ((_interval_us == 0) || (hrt_elapsed_time(&_last_update) >= _interval_us)) {
 			_work_item->ScheduleNow();
 		}
 	}

src/modules/uORB/SubscriptionInterval.hpp

@@ -64,13 +64,15 @@ public:
 	 */
 	SubscriptionInterval(const orb_metadata *meta, uint32_t interval_us = 0, uint8_t instance = 0) :
 		_subscription{meta, instance},
-		_interval(interval_us)
+		_interval_us(interval_us)
 	{}
 
 	SubscriptionInterval() : _subscription{nullptr} {}
 
 	~SubscriptionInterval() = default;
 
+	bool subscribe() { return _subscription.subscribe(); }
+
 	bool published() { return _subscription.published(); }
 
 	/**
@@ -78,7 +80,7 @@ public:
 	 * */
 	bool updated()
 	{
-		if (published() && (hrt_elapsed_time(&_last_update) >= _interval)) {
+		if (published() && (hrt_elapsed_time(&_last_update) >= _interval_us)) {
 			return _subscription.updated();
 		}
 
@@ -118,15 +120,24 @@ public:
 
 	uint8_t		get_instance() const { return _subscription.get_instance(); }
 	orb_id_t	get_topic() const { return _subscription.get_topic(); }
-	uint32_t	get_interval() const { return _interval; }
 
-	void		set_interval(uint32_t interval) { _interval = interval; }
+	/**
+	 * Set the interval in microseconds
+	 * @param interval The interval in microseconds.
+	 */
+	void		set_interval_us(uint32_t interval) { _interval_us = interval; }
+
+	/**
+	 * Set the interval in milliseconds
+	 * @param interval The interval in milliseconds.
+	 */
+	void		set_interval_ms(uint32_t interval) { _interval_us = interval * 1000; }
 
 protected:
 
 	Subscription	_subscription;
 	uint64_t	_last_update{0};	// last update in microseconds
-	uint32_t	_interval{0};		// maximum update interval in microseconds
+	uint32_t	_interval_us{0};		// maximum update interval in microseconds
 
 };
 

src/modules/uORB/uORBDeviceMaster.cpp

@@ -430,6 +430,10 @@ uORB::DeviceNode *uORB::DeviceMaster::getDeviceNode(const char *nodepath)
 
 uORB::DeviceNode *uORB::DeviceMaster::getDeviceNode(const struct orb_metadata *meta, const uint8_t instance)
 {
+	if (meta == nullptr) {
+		return nullptr;
+	}
+
 	lock();
 	uORB::DeviceNode *node = getDeviceNodeLocked(meta, instance);
 	unlock();

src/modules/uORB/uORBDeviceNode.cpp

@@ -220,18 +220,6 @@ uORB::DeviceNode::copy_and_get_timestamp(void *dst, unsigned &generation)
 	return update_time;
 }
 
-hrt_abstime
-uORB::DeviceNode::last_update()
-{
-	ATOMIC_ENTER;
-
-	const hrt_abstime update_time = _last_update;
-
-	ATOMIC_LEAVE;
-
-	return update_time;
-}
-
 ssize_t
 uORB::DeviceNode::read(cdev::file_t *filp, char *buffer, size_t buflen)
 {

src/modules/uORB/uORBDeviceNode.hpp

@@ -196,14 +196,6 @@ public:
 	int get_priority() const { return _priority; }
 	void set_priority(uint8_t priority) { _priority = priority; }
 
-	/**
-	 * Copies the timestamp of the last update atomically.
-	 *
-	 * @return uint64_t
-	 *   Returns the timestamp of the most recent data.
-	 */
-	hrt_abstime last_update();
-
 	/**
 	 * Copies data and the corresponding generation
 	 * from a node to the buffer provided.

src/systemcmds/tests/test_microbench_uorb.cpp

@@ -188,21 +188,18 @@ bool MicroBenchORB::time_px4_uorb_direct()
 
 	uORB::Subscription vstatus{ORB_ID(vehicle_status)};
 	PERF("uORB::Subscription orb_check vehicle_status", ret = vstatus.updated(), 1000);
-	PERF("uORB::Subscription orb_stat vehicle_status", time = vstatus.last_update(), 1000);
 	PERF("uORB::Subscription orb_copy vehicle_status", ret = vstatus.copy(&status), 1000);
 
 	printf("\n");
 
 	uORB::Subscription local_pos{ORB_ID(vehicle_local_position)};
 	PERF("uORB::Subscription orb_check vehicle_local_position", ret = local_pos.updated(), 1000);
-	PERF("uORB::Subscription orb_stat vehicle_local_position", time = local_pos.last_update(), 1000);
 	PERF("uORB::Subscription orb_copy vehicle_local_position", ret = local_pos.copy(&lpos), 1000);
 
 	printf("\n");
 
 	uORB::Subscription sens_gyro{ORB_ID(sensor_gyro)};
 	PERF("uORB::Subscription orb_check sensor_gyro", ret = sens_gyro.updated(), 1000);
-	PERF("uORB::Subscription orb_stat sensor_gyro", time = sens_gyro.last_update(), 1000);
 	PERF("uORB::Subscription orb_copy sensor_gyro", ret = sens_gyro.copy(&gyro), 1000);
 
 	return true;