Move bootloader main to examples

This should remove some confusion around embassy-boot-* being a library
vs. a binary. The binary is now an example bootloader instead.

examples/boot/application/stm32l0/src/bin/a.rs

@@ -0,0 +1,44 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[cfg(feature = "defmt-rtt")]
+use defmt_rtt::*;
+use embassy::time::{Duration, Timer};
+use embassy_boot_stm32::FirmwareUpdater;
+use embassy_embedded_hal::adapter::BlockingAsync;
+use embassy_stm32::exti::ExtiInput;
+use embassy_stm32::flash::Flash;
+use embassy_stm32::gpio::{Input, Level, Output, Pull, Speed};
+use embassy_stm32::Peripherals;
+use panic_reset as _;
+
+static APP_B: &[u8] = include_bytes!("../../b.bin");
+
+#[embassy::main]
+async fn main(_s: embassy::executor::Spawner, p: Peripherals) {
+    let flash = Flash::unlock(p.FLASH);
+    let mut flash = BlockingAsync::new(flash);
+
+    let button = Input::new(p.PB2, Pull::Up);
+    let mut button = ExtiInput::new(button, p.EXTI2);
+
+    let mut led = Output::new(p.PB5, Level::Low, Speed::Low);
+
+    led.set_high();
+
+    let mut updater = FirmwareUpdater::default();
+    button.wait_for_falling_edge().await;
+    let mut offset = 0;
+    for chunk in APP_B.chunks(128) {
+        let mut buf: [u8; 128] = [0; 128];
+        buf[..chunk.len()].copy_from_slice(chunk);
+        updater.write_firmware(offset, &buf, &mut flash, 128).await.unwrap();
+        offset += chunk.len();
+    }
+
+    updater.update(&mut flash).await.unwrap();
+    led.set_low();
+    Timer::after(Duration::from_secs(1)).await;
+    cortex_m::peripheral::SCB::sys_reset();
+}

examples/boot/application/stm32l0/src/bin/b.rs

@@ -0,0 +1,24 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[cfg(feature = "defmt-rtt")]
+use defmt_rtt::*;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_stm32::Peripherals;
+use panic_reset as _;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let mut led = Output::new(p.PB6, Level::High, Speed::Low);
+
+    loop {
+        led.set_high();
+        Timer::after(Duration::from_millis(500)).await;
+
+        led.set_low();
+        Timer::after(Duration::from_millis(500)).await;
+    }
+}