Change IPC to exchange data, not pointers.

firmware/common/message.hpp

@@ -31,7 +31,9 @@
 
 class Message {
 public:
-	enum class ID : uint16_t {
+	static constexpr size_t MAX_SIZE = 276;
+
+	enum class ID : uint32_t {
 		/* Assign consecutive IDs. IDs are used to index array. */
 		RSSIStatistics = 0,
 		BasebandStatistics = 1,
@@ -47,22 +49,11 @@ public:
 
 	constexpr Message(
 		ID id
-	) : id { id },
-		state { State::Free }
+	) : id { id }
 	{
 	}
 
-	enum class State : uint16_t {
-		Free,
-		InUse,
-	};
-
-	bool is_free() const {
-		return state == State::Free;
-	}
-
 	const ID id;
-	volatile State state;
 };
 
 struct RSSIStatistics {
@@ -183,7 +174,7 @@ public:
 };
 
 struct ChannelSpectrum {
-	std::array<uint8_t, 256>* db { nullptr };
+	std::array<uint8_t, 256> db { { 0 } };
 	size_t db_count { 256 };
 	uint32_t sampling_rate { 0 };
 	uint32_t channel_filter_pass_frequency { 0 };
@@ -255,9 +246,11 @@ public:
 	}
 
 	void send(const Message* const message) {
-		auto& fn = map_[toUType(message->id)];
-		if( fn ) {
-			fn(message);
+		if( message->id < Message::ID::MAX ) {
+			auto& fn = map_[toUType(message->id)];
+			if( fn ) {
+				fn(message);
+			}
 		}
 	}
 

firmware/common/message_queue.cpp

@@ -26,56 +26,26 @@
 
 using namespace lpc43xx;
 
-bool MessageQueue::push(Message* const message) {
-	/* Returns true if success:
-	 * - Message not in use.
-	 * - FIFO wasn't full.
-	 */
-	if( message->state == Message::State::Free ) {
-		message->state = Message::State::InUse;
-
-		if(	enqueue(message) ) {
-			signal();
-			return true;
-		} else {
-			// Roll back message state.
-			message->state = Message::State::Free;
-		}
+bool MessageQueue::push(const void* const buf, const size_t len) {
+	const auto result = fifo.in_r(buf, len);
+	const bool success = (result == len);
+	if( success ) {
+		signal();
 	}
-
-	return false;
+	return success;
 }
 
-Message* MessageQueue::pop() {
-	/* TODO: Because of architecture characteristics, the two LSBs of the
-	 * message pointer will always be 0. Other (non-pointer) message types
-	 * could be encoded by setting these two bits to non-zero values.
-	 * One of the bits could also be used as an "ack" flag... In fact, a
-	 * pointer message could be turned into an "ack" message, or something
-	 * like that...
-	 * Might be better though to use formal operating structures in the
-	 * message to do synchronization between processors.
-	 */
-	Message* message { nullptr };
-	const auto success = fifo.out(&message, 1);
-	return success ? message : nullptr;
+size_t MessageQueue::pop(void* const buf, const size_t len) {
+	return fifo.out_r(buf, len);
 }
 
 #if defined(LPC43XX_M0)
-bool MessageQueue::enqueue(Message* const message) {
-	return fifo.in(&message, 1);
-}
-
 void MessageQueue::signal() {
 	creg::m0apptxevent::assert();
 }
 #endif
 
 #if defined(LPC43XX_M4)
-bool MessageQueue::enqueue(Message* const message) {
-	return fifo.in(&message, 1);
-}
-
 void MessageQueue::signal() {
 	creg::m4txevent::assert();
 }

firmware/common/message_queue.hpp

@@ -29,9 +29,15 @@
 
 class MessageQueue {
 public:
-	bool push(Message* const message);
+	template<typename T>
+	bool push(const T& message) {
+		static_assert(sizeof(T) <= Message::MAX_SIZE, "Message::MAX_SIZE too small for message type");
+		static_assert(std::is_base_of<Message, T>::value, "type is not based on Message");
 
-	Message* pop();
+		return push(&message, sizeof(message));
+	}
+
+	size_t pop(void* const buf, const size_t len);
 
 	size_t len() const {
 		return fifo.len();
@@ -42,9 +48,10 @@ public:
 	}
 
 private:
-	FIFO<Message*, 8> fifo;
+	FIFO<uint8_t, 11> fifo;
+
+	bool push(const void* const buf, const size_t len);
 
-	bool enqueue(Message* const message);
 	void signal();
 };