External apps (#1469)

* implemented external app build

* added some ui stuff for testing

* added pacman game

* wired key to pacman game

* fixed pacman drawing issue

* changed afsk rx app to be external

* fixed ui::NavigationView initialization for external apps

* refactoring

* refactoring

* moved m4 image to external app

* added script for external app deployment

* refactoring

* implemented dynamic app listing

* added color to app icon

* improved app loading

* added external apps to sd card content

* refactoring

* review findings

* typo

* review findings

* improved memory management of bitmaps

firmware/application/core_control.cpp

@@ -59,6 +59,19 @@ void m4_init(const spi_flash::image_tag_t image_tag, const memory::region_t to,
     chDbgPanic("NoImg");
 }
 
+void m4_init_prepared(const uint32_t m4_code, const bool full_reset) {
+    /* M4 core is assumed to be sleeping with interrupts off, so we can mess
+     * with its address space and RAM without concern.
+     */
+    LPC_CREG->M4MEMMAP = m4_code;
+
+    /* Reset M4 core and optionally all peripherals */
+    LPC_RGU->RESET_CTRL[0] = (full_reset) ? (1 << 1)    // PERIPH_RST
+                                          : (1 << 13);  // M4_RST
+
+    return;
+}
+
 void m4_request_shutdown() {
     baseband::shutdown();
 }