Capture M4 chDbgPanic msg, show in application.

firmware/application/event_m0.cpp

@@ -40,6 +40,8 @@ using namespace lpc43xx;
 
 #include <array>
 
+#include "ui_font_fixed_8x16.hpp"
+
 extern "C" {
 
 CH_IRQ_HANDLER(M4Core_IRQHandler) {
@@ -133,6 +135,40 @@ eventmask_t EventDispatcher::wait() {
 }
 
 void EventDispatcher::dispatch(const eventmask_t events) {
+	if( shared_memory.m4_panic_msg[0] != 0 ) {
+		halt = true;
+	}
+
+	if( halt ) {
+		if( shared_memory.m4_panic_msg[0] != 0 ) {
+			painter.fill_rectangle(
+				{ 0, 0, portapack::display.width(), portapack::display.height() },
+				ui::Color::red()
+			);
+
+			constexpr int border = 8;
+			painter.fill_rectangle(
+				{ border, border, portapack::display.width() - (border * 2), portapack::display.height() - (border * 2) },
+				ui::Color::black()
+			);
+
+			painter.draw_string({ 48, 24 }, top_widget->style(), "M4 Guru Meditation");
+
+			shared_memory.m4_panic_msg[sizeof(shared_memory.m4_panic_msg) - 1] = 0;
+			const std::string message = shared_memory.m4_panic_msg;
+			const int x_offset = (portapack::display.width() - (message.size() * 8)) / 2;
+			constexpr int y_offset = (portapack::display.height() - 16) / 2;
+			painter.draw_string(
+				{ x_offset, y_offset },
+				top_widget->style(),
+				message
+			);
+
+			shared_memory.m4_panic_msg[0] = 0;
+		}
+		return;
+	}
+
 	if( events & EVT_MASK_APPLICATION ) {
 		handle_application_queue();
 	}
@@ -291,6 +327,7 @@ void EventDispatcher::init_message_queues() {
 	new (&shared_memory.app_local_queue) MessageQueue(
 		shared_memory.app_local_queue_data, SharedMemory::app_local_queue_k
 	);
+	shared_memory.m4_panic_msg[0] = 0;
 }
 
 MessageHandlerRegistration::MessageHandlerRegistration(

firmware/application/event_m0.hpp

@@ -102,6 +102,7 @@ private:
 	bool is_running = true;
 	bool sd_card_present = false;
 	bool display_sleep = false;
+	bool halt = false;
 
 	eventmask_t wait();
 	void dispatch(const eventmask_t events);

firmware/common/debug.cpp

@@ -24,6 +24,8 @@
 #include <ch.h>
 #include <hal.h>
 
+#include "portapack_shared_memory.hpp"
+
 #if defined(LPC43XX_M0)
 static void debug_indicate_error_init() {
 	// TODO: Get knowledge of LED GPIO port/bit from shared place.
@@ -75,6 +77,16 @@ void __early_init(void) {
 }
 
 void port_halt(void) {
+	// Copy debug panic message to M0 region.
+	const auto* p = dbg_panic_msg;
+	for(size_t i=0; i<sizeof(shared_memory.m4_panic_msg); i++) {
+		if( *p == 0 ) {
+			shared_memory.m4_panic_msg[i] = 0;
+		} else {
+			shared_memory.m4_panic_msg[i] = *(p++);
+		}
+	}
+
 	port_disable();
 	runtime_error();
 }

firmware/common/portapack_shared_memory.hpp

@@ -45,6 +45,8 @@ struct SharedMemory {
 	// TODO: M0 should directly configure and control DMA channel that is
 	// acquiring ADC samples.
 	TouchADCFrame touch_adc_frame;
+
+	char m4_panic_msg[32];
 };
 
 extern SharedMemory& shared_memory;