feat: embassy-boot for rp2040

Add embassy-boot support for RP2040, with examples for the Raspberry Pi
Pico.

Co-authored-by: Mathias Koch <mk@blackbird.online>

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

@@ -0,0 +1,52 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt_rtt as _;
+use embassy_boot_rp::*;
+use embassy_executor::Spawner;
+use embassy_rp::flash::Flash;
+use embassy_rp::gpio::{Level, Output};
+use embassy_time::{Duration, Timer};
+#[cfg(feature = "panic-probe")]
+use panic_probe as _;
+#[cfg(feature = "panic-reset")]
+use panic_reset as _;
+
+static APP_B: &[u8] = include_bytes!("../../b.bin");
+const FLASH_SIZE: usize = 2 * 1024 * 1024;
+
+#[embassy_executor::main]
+async fn main(_s: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let mut led = Output::new(p.PIN_25, Level::Low);
+
+    let mut flash: Flash<_, FLASH_SIZE> = Flash::new(p.FLASH);
+
+    let mut updater = FirmwareUpdater::default();
+
+    Timer::after(Duration::from_secs(5)).await;
+    led.set_high();
+    let mut offset = 0;
+    let mut buf: AlignedBuffer<4096> = AlignedBuffer([0; 4096]);
+    defmt::info!("preparing update");
+    let mut writer = updater
+        .prepare_update_blocking(&mut flash)
+        .map_err(|e| defmt::warn!("E: {:?}", defmt::Debug2Format(&e)))
+        .unwrap();
+    defmt::info!("writer created, starting write");
+    for chunk in APP_B.chunks(4096) {
+        buf.0[..chunk.len()].copy_from_slice(chunk);
+        defmt::info!("writing block at offset {}", offset);
+        writer
+            .write_block_blocking(offset, &buf.0[..], &mut flash, 256)
+            .unwrap();
+        offset += chunk.len();
+    }
+    defmt::info!("firmware written, marking update");
+    updater.mark_updated_blocking(&mut flash, &mut buf.0[..1]).unwrap();
+    Timer::after(Duration::from_secs(2)).await;
+    led.set_low();
+    defmt::info!("update marked, resetting");
+    cortex_m::peripheral::SCB::sys_reset();
+}

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

@@ -0,0 +1,23 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use embassy_executor::Spawner;
+use embassy_rp::gpio;
+use embassy_time::{Duration, Timer};
+use gpio::{Level, Output};
+use {defmt_rtt as _, panic_reset as _};
+
+#[embassy_executor::main]
+async fn main(_s: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let mut led = Output::new(p.PIN_25, Level::Low);
+
+    loop {
+        led.set_high();
+        Timer::after(Duration::from_millis(100)).await;
+
+        led.set_low();
+        Timer::after(Duration::from_millis(100)).await;
+    }
+}