bootloader: Only attempt to jump to application if there is any.

We now read the first word from flash where the application is
installed and compare against 0xffffffff to see if programming
succeeded.

diff --git a/src/bootloader/main.rs b/src/bootloader/main.rs
index 0d2954909572a02f26432aef8147c5894dfaff47..8c6f149e19534d93326a7df4abf290a8a37044ed 100644 (file)
--- a/src/bootloader/main.rs
+++ b/src/bootloader/main.rs
@@ -30,12 +30,15 @@ extern crate common;
 mod flash;
 mod bootloader;
 
+use common::register;
 use common::clock;
 use common::systick;
 use common::port;
 use common::gpio;
 use common::usb_serial;
 
+type Reg32 = register::Register<u32>;
+
 extern {
     fn jump_to_application(address: u32);
 }
@@ -46,6 +49,12 @@ const APPLICATION_ADDR: u32 = 0x0;
 #[cfg(bootloader_type = "final")]
 const APPLICATION_ADDR: u32 = 0x8000;
 
+unsafe fn application_missing() -> bool {
+    let first_app_word = Reg32::new(APPLICATION_ADDR);
+
+    first_app_word.read() == 0xffffffff
+}
+
 fn bootloader_requested() -> bool {
     let start_ticks = systick::now();
 
@@ -68,12 +77,12 @@ pub unsafe extern fn main() {
     port::set_af(port::PORTE, 24, 1);
     port::set_pull(port::PORTE, 24, port::Pull::Up);
 
-    if bootloader_requested() {
+    if application_missing() || bootloader_requested() {
         usb_serial::init(0xf055, 0x635c);
 
         let mut b = bootloader::Bootloader::new();
 
-        while b.run() {
+        while b.run() || application_missing() {
         }
     }