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/.cargo/config.toml

@@ -0,0 +1,9 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# replace your chip as listed in `probe-run --list-chips`
+runner = "probe-run --chip STM32L072CZTx"
+
+[build]
+target = "thumbv6m-none-eabi"
+
+[env]
+DEFMT_LOG = "trace"

examples/boot/application/stm32l0/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+edition = "2021"
+name = "embassy-boot-stm32l0-examples"
+version = "0.1.0"
+
+[dependencies]
+embassy = { version = "0.1.0", path = "../../../../embassy", features = ["nightly", "time-tick-32768hz"] }
+embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32l072cz", "time-driver-any", "exti", "memory-x"]  }
+embassy-boot-stm32 = { version = "0.1.0", path = "../../../../embassy-boot/stm32" }
+embassy-embedded-hal = { version = "0.1.0", path = "../../../../embassy-embedded-hal" }
+
+defmt = { version = "0.3", optional = true }
+defmt-rtt = { version = "0.3", optional = true }
+panic-reset = { version = "0.1.1" }
+embedded-hal = { version = "0.2.6" }
+
+cortex-m = "0.7.3"
+cortex-m-rt = "0.7.0"
+
+[features]
+defmt = [
+      "dep:defmt",
+      "embassy-stm32/defmt",
+      "embassy-boot-stm32/defmt",
+]

examples/boot/application/stm32l0/README.md

@@ -0,0 +1,29 @@
+# Examples using bootloader
+
+Example for STM32L0 demonstrating the bootloader. The example consists of application binaries, 'a'
+which allows you to press a button to start the DFU process, and 'b' which is the updated
+application.
+
+
+## Prerequisites
+
+* `cargo-binutils`
+* `cargo-flash`
+* `embassy-boot-stm32`
+
+## Usage
+
+```
+# Flash bootloader
+cargo flash --manifest-path ../../bootloader/stm32/Cargo.toml --release --features embassy-stm32/stm32l072cz --chip STM32L072CZTx
+# Build 'b'
+cargo build --release --bin b
+# Generate binary for 'b'
+cargo objcopy --release --bin b -- -O binary b.bin
+```
+
+# Flash `a` (which includes b.bin)
+
+```
+cargo flash --release --bin a --chip STM32L072CZTx
+```

examples/boot/application/stm32l0/build.rs

@@ -0,0 +1,37 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    // By default, Cargo will re-run a build script whenever
+    // any file in the project changes. By specifying `memory.x`
+    // here, we ensure the build script is only re-run when
+    // `memory.x` is changed.
+    println!("cargo:rerun-if-changed=memory.x");
+
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    if env::var("CARGO_FEATURE_DEFMT").is_ok() {
+        println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+    }
+}

examples/boot/application/stm32l0/memory.x

@@ -0,0 +1,15 @@
+MEMORY
+{
+  /* NOTE 1 K = 1 KiBi = 1024 bytes */
+  BOOTLOADER                        : ORIGIN = 0x08000000, LENGTH = 24K
+  BOOTLOADER_STATE                  : ORIGIN = 0x08006000, LENGTH = 4K
+  FLASH                             : ORIGIN = 0x08008000, LENGTH = 32K
+  DFU                               : ORIGIN = 0x08010000, LENGTH = 36K
+  RAM                         (rwx) : ORIGIN = 0x20000008, LENGTH = 16K
+}
+
+__bootloader_state_start = ORIGIN(BOOTLOADER_STATE) - ORIGIN(BOOTLOADER);
+__bootloader_state_end = ORIGIN(BOOTLOADER_STATE) + LENGTH(BOOTLOADER_STATE) - ORIGIN(BOOTLOADER);
+
+__bootloader_dfu_start = ORIGIN(DFU) - ORIGIN(BOOTLOADER);
+__bootloader_dfu_end = ORIGIN(DFU) + LENGTH(DFU) - ORIGIN(BOOTLOADER);

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;
+    }
+}