Simplify app->baseband message handling.

No need for a FIFO when all messages are intended to be synchronous.

firmware/application/baseband_api.cpp

@@ -30,6 +30,14 @@
 
 namespace baseband {
 
+static void send_message(const Message* const message) {
+	// If message is only sent by this function via one thread, no need to check if
+	// another message is present before setting new message.
+	shared_memory.baseband_message = message;
+	creg::m0apptxevent::assert();
+	while(shared_memory.baseband_message);
+}
+
 void AMConfig::apply() const {
 	const AMConfigureMessage message {
 		taps_6k0_decim_0,
@@ -39,7 +47,7 @@ void AMConfig::apply() const {
 		modulation,
 		audio_12k_hpf_300hz_config
 	};
-	shared_memory.baseband_queue.push_and_wait(message);
+	send_message(&message);
 	audio::set_rate(audio::Rate::Hz_12000);
 }
 
@@ -53,7 +61,7 @@ void NBFMConfig::apply() const {
 		audio_24k_hpf_300hz_config,
 		audio_24k_deemph_300_6_config
 	};
-	shared_memory.baseband_queue.push_and_wait(message);
+	send_message(&message);
 	audio::set_rate(audio::Rate::Hz_24000);
 }
 
@@ -66,21 +74,20 @@ void WFMConfig::apply() const {
 		audio_48k_hpf_30hz_config,
 		audio_48k_deemph_2122_6_config
 	};
-	shared_memory.baseband_queue.push_and_wait(message);
+	send_message(&message);
 	audio::set_rate(audio::Rate::Hz_48000);
 }
 
 void start(BasebandConfiguration configuration) {
 	BasebandConfigurationMessage message { configuration };
-	shared_memory.baseband_queue.push_and_wait(message);
+	send_message(&message);
 }
 
 void stop() {
-	shared_memory.baseband_queue.push_and_wait(
+	BasebandConfigurationMessage message {
-		BasebandConfigurationMessage {
 		.configuration = { },
-		}
+	};
-	);
+	send_message(&message);
 }
 
 void run_image(const portapack::spi_flash::region_t image_region) {
@@ -92,36 +99,32 @@ void run_image(const portapack::spi_flash::region_t image_region) {
 void shutdown() {
 	creg::m4txevent::disable();
 
-	ShutdownMessage shutdown_message;
+	ShutdownMessage message;
-	shared_memory.baseband_queue.push_and_wait(shutdown_message);
+	send_message(&message);
 }
 
 void spectrum_streaming_start() {
-	shared_memory.baseband_queue.push_and_wait(
+	SpectrumStreamingConfigMessage message {
-		SpectrumStreamingConfigMessage {
 		SpectrumStreamingConfigMessage::Mode::Running
-		}
+	};
-	);
+	send_message(&message);
 }
 
 void spectrum_streaming_stop() {
-	shared_memory.baseband_queue.push_and_wait(
+	SpectrumStreamingConfigMessage message {
-		SpectrumStreamingConfigMessage {
 		SpectrumStreamingConfigMessage::Mode::Stopped
-		}
+	};
-	);
+	send_message(&message);
 }
 
 void capture_start(CaptureConfig* const config) {
-	shared_memory.baseband_queue.push_and_wait(
+	CaptureConfigMessage message { config };
-		CaptureConfigMessage { config }
+	send_message(&message);
-	);
 }
 
 void capture_stop() {
-	shared_memory.baseband_queue.push_and_wait(
+	CaptureConfigMessage message { nullptr };
-		CaptureConfigMessage { nullptr }
+	send_message(&message);
-	);
 }
 
 } /* namespace baseband */

firmware/application/event_m0.cpp

@@ -284,9 +284,7 @@ void EventDispatcher::event_bubble_encoder(const ui::EncoderEvent event) {
 }
 
 void EventDispatcher::init_message_queues() {
-	new (&shared_memory.baseband_queue) MessageQueue(
+	shared_memory.baseband_message = nullptr;
-		shared_memory.baseband_queue_data, SharedMemory::baseband_queue_k
-	);
 	new (&shared_memory.application_queue) MessageQueue(
 		shared_memory.application_queue_data, SharedMemory::application_queue_k
 	);

firmware/baseband/event_m4.cpp

@@ -87,9 +87,11 @@ void EventDispatcher::dispatch(const eventmask_t events) {
 }
 
 void EventDispatcher::handle_baseband_queue() {
-	shared_memory.baseband_queue.handle([this](Message* const message) {
+	const auto message = shared_memory.baseband_message;
-		this->on_message(message);
+	if( message ) {
-	});
+		on_message(message);
+		shared_memory.baseband_message = nullptr;
+	}
 }
 
 void EventDispatcher::on_message(const Message* const message) {

firmware/common/portapack_shared_memory.hpp

@@ -33,14 +33,12 @@ struct TouchADCFrame {
 
 /* NOTE: These structures must be located in the same location in both M4 and M0 binaries */
 struct SharedMemory {
-	static constexpr size_t baseband_queue_k = 11;
 	static constexpr size_t application_queue_k = 11;
 	static constexpr size_t app_local_queue_k = 11;
 
-	uint8_t baseband_queue_data[1 << baseband_queue_k];
 	uint8_t application_queue_data[1 << application_queue_k];
 	uint8_t app_local_queue_data[1 << app_local_queue_k];
-	MessageQueue baseband_queue;
+	const Message* volatile baseband_message;
 	MessageQueue application_queue;
 	MessageQueue app_local_queue;