Triggering the dfu bootloader works

firmware/src/bootloader.rs

@@ -0,0 +1,59 @@
+use core::ptr::addr_of_mut;
+
+use stm32f4xx_hal::pac;
+
+fn jump_to_bootloader() {
+    unsafe {
+        cortex_m::interrupt::disable();
+
+        let address: u32 = 0x1FFF0000;
+
+        let device = pac::Peripherals::steal();
+        device.SYSCFG.memrm.modify(|_, w| w.bits(0x01));
+
+        let mut p = cortex_m::Peripherals::steal();
+        p.SCB.invalidate_icache();
+        p.SCB.vtor.write(address as u32);
+
+        cortex_m::interrupt::enable();
+
+        cortex_m::asm::bootload(address as *const u32);
+    }
+}
+
+const BOOTLOADER_REQUESTED: u32 = 0xdecafbad;
+
+fn magic_mut_ptr() -> *mut u32 {
+    extern "C" {
+        #[link_name = "_dfu_magic"]
+        static mut magic: u32;
+    }
+
+    unsafe { addr_of_mut!(magic) }
+}
+
+fn get_bootloader_flag() -> u32 {
+    unsafe { magic_mut_ptr().read_volatile() }
+}
+
+fn set_bootloader_flag() {
+    unsafe { magic_mut_ptr().write_volatile(BOOTLOADER_REQUESTED) };
+}
+
+fn clear_bootloader_flag() {
+    unsafe { magic_mut_ptr().write_volatile(BOOTLOADER_REQUESTED) };
+}
+
+pub fn init() {
+    let requested = get_bootloader_flag() == BOOTLOADER_REQUESTED;
+    if requested {
+        clear_bootloader_flag();
+        jump_to_bootloader();
+    }
+}
+
+pub fn reboot_to_bootloader() -> ! {
+    defmt::info!("Rebooting into the bootloader");
+    set_bootloader_flag();
+    cortex_m::peripheral::SCB::sys_reset();
+}