Add embassy-boot

Embassy-boot is a simple bootloader that works together with an
application to provide firmware update capabilities with a minimal risk.

The bootloader consists of a platform-independent part, which implements
the swap algorithm, and a platform-dependent part (currently only for
nRF) that provides addition functionality such as watchdog timers
softdevice support.

embassy-boot/nrf/.cargo/config.toml

@@ -0,0 +1,18 @@
+[unstable]
+namespaced-features = true
+build-std = ["core"]
+build-std-features = ["panic_immediate_abort"]
+
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+#runner = "./fruitrunner"
+runner = "probe-run --chip nrf52840_xxAA"
+
+rustflags = [
+  # Code-size optimizations.
+  "-Z", "trap-unreachable=no",
+  #"-C", "no-vectorize-loops",
+  "-C", "force-frame-pointers=yes",
+]
+
+[build]
+target = "thumbv7em-none-eabi"

embassy-boot/nrf/Cargo.toml

@@ -0,0 +1,65 @@
+[package]
+authors = [
+    "Ulf Lilleengen <lulf@redhat.com>",
+]
+edition = "2018"
+name = "embassy-boot-nrf"
+version = "0.1.0"
+description = "Bootloader for nRF chips"
+
+[dependencies]
+defmt = { version = "0.3", optional = true }
+defmt-rtt = { version = "0.3", optional = true }
+
+embassy = { path = "../../embassy", default-features = false }
+embassy-nrf = { path = "../../embassy-nrf", default-features = false }
+embassy-boot = { path = "../boot", default-features = false }
+cortex-m = { version = "0.7" }
+cortex-m-rt = { version = "0.7" }
+embedded-storage = "0.3.0"
+embedded-storage-async = "0.3.0"
+cfg-if = "1.0.0"
+
+nrf-softdevice-mbr = { version = "0.1.0", git = "https://github.com/embassy-rs/nrf-softdevice.git", branch = "master", optional = true }
+
+[features]
+defmt = [
+    "dep:defmt",
+    "embassy-boot/defmt",
+    "embassy-nrf/defmt",
+]
+softdevice = [
+    "nrf-softdevice-mbr",
+]
+debug = ["defmt-rtt"]
+
+[profile.dev]
+debug = 2
+debug-assertions = true
+incremental = false
+opt-level = 'z'
+overflow-checks = true
+
+[profile.release]
+codegen-units = 1
+debug = 2
+debug-assertions = false
+incremental = false
+lto = 'fat'
+opt-level = 'z'
+overflow-checks = false
+
+# do not optimize proc-macro crates = faster builds from scratch
+[profile.dev.build-override]
+codegen-units = 8
+debug = false
+debug-assertions = false
+opt-level = 0
+overflow-checks = false
+
+[profile.release.build-override]
+codegen-units = 8
+debug = false
+debug-assertions = false
+opt-level = 0
+overflow-checks = false

embassy-boot/nrf/README.md

@@ -0,0 +1,11 @@
+# Bootloader for nRF
+
+The bootloader uses `embassy-boot` to interact with the flash.
+
+# Usage
+
+Flash the bootloader
+
+```
+cargo flash --features embassy-nrf/nrf52832 --release --chip nRF52832_xxAA
+```

embassy-boot/nrf/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");
+    }
+}

embassy-boot/nrf/memory-bm.x

@@ -0,0 +1,18 @@
+MEMORY
+{
+  /* NOTE 1 K = 1 KiBi = 1024 bytes */
+  FLASH                             : ORIGIN = 0x00000000, LENGTH = 24K
+  BOOTLOADER_STATE                  : ORIGIN = 0x00006000, LENGTH = 4K
+  ACTIVE                            : ORIGIN = 0x00007000, LENGTH = 64K
+  DFU                               : ORIGIN = 0x00017000, LENGTH = 68K
+  RAM                         (rwx) : ORIGIN = 0x20000000, LENGTH = 32K
+}
+
+__bootloader_state_start = ORIGIN(BOOTLOADER_STATE);
+__bootloader_state_end = ORIGIN(BOOTLOADER_STATE) + LENGTH(BOOTLOADER_STATE);
+
+__bootloader_active_start = ORIGIN(ACTIVE);
+__bootloader_active_end = ORIGIN(ACTIVE) + LENGTH(ACTIVE);
+
+__bootloader_dfu_start = ORIGIN(DFU);
+__bootloader_dfu_end = ORIGIN(DFU) + LENGTH(DFU);

embassy-boot/nrf/memory-s140.x

@@ -0,0 +1,31 @@
+MEMORY
+{
+  /* NOTE 1 K = 1 KiBi = 1024 bytes */
+  MBR                               : ORIGIN = 0x00000000, LENGTH = 4K
+  SOFTDEVICE                        : ORIGIN = 0x00001000, LENGTH = 155648
+  ACTIVE                            : ORIGIN = 0x00027000, LENGTH = 425984
+  DFU                               : ORIGIN = 0x0008F000, LENGTH = 430080
+  FLASH                             : ORIGIN = 0x000f9000, LENGTH = 24K
+  BOOTLOADER_STATE                  : ORIGIN = 0x000ff000, LENGTH = 4K
+  RAM                         (rwx) : ORIGIN = 0x20000008, LENGTH = 0x2fff8
+  uicr_bootloader_start_address (r) : ORIGIN = 0x10001014, LENGTH = 0x4
+}
+
+__bootloader_state_start = ORIGIN(BOOTLOADER_STATE);
+__bootloader_state_end = ORIGIN(BOOTLOADER_STATE) + LENGTH(BOOTLOADER_STATE);
+
+__bootloader_active_start = ORIGIN(ACTIVE);
+__bootloader_active_end = ORIGIN(ACTIVE) + LENGTH(ACTIVE);
+
+__bootloader_dfu_start = ORIGIN(DFU);
+__bootloader_dfu_end = ORIGIN(DFU) + LENGTH(DFU);
+
+__bootloader_start = ORIGIN(FLASH);
+
+SECTIONS
+{
+  .uicr_bootloader_start_address :
+  {
+    LONG(__bootloader_start)
+  } > uicr_bootloader_start_address
+}

embassy-boot/nrf/memory.x

@@ -0,0 +1,18 @@
+MEMORY
+{
+  /* NOTE 1 K = 1 KiBi = 1024 bytes */
+  FLASH                             : ORIGIN = 0x00000000, LENGTH = 24K
+  BOOTLOADER_STATE                  : ORIGIN = 0x00006000, LENGTH = 4K
+  ACTIVE                            : ORIGIN = 0x00007000, LENGTH = 64K
+  DFU                               : ORIGIN = 0x00017000, LENGTH = 68K
+  RAM                         (rwx) : ORIGIN = 0x20000000, LENGTH = 32K
+}
+
+__bootloader_state_start = ORIGIN(BOOTLOADER_STATE);
+__bootloader_state_end = ORIGIN(BOOTLOADER_STATE) + LENGTH(BOOTLOADER_STATE);
+
+__bootloader_active_start = ORIGIN(ACTIVE);
+__bootloader_active_end = ORIGIN(ACTIVE) + LENGTH(ACTIVE);
+
+__bootloader_dfu_start = ORIGIN(DFU);
+__bootloader_dfu_end = ORIGIN(DFU) + LENGTH(DFU);

embassy-boot/nrf/src/fmt.rs

@@ -0,0 +1,225 @@
+#![macro_use]
+#![allow(unused_macros)]
+
+#[cfg(all(feature = "defmt", feature = "log"))]
+compile_error!("You may not enable both `defmt` and `log` features.");
+
+macro_rules! assert {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::assert!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::assert!($($x)*);
+        }
+    };
+}
+
+macro_rules! assert_eq {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::assert_eq!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::assert_eq!($($x)*);
+        }
+    };
+}
+
+macro_rules! assert_ne {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::assert_ne!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::assert_ne!($($x)*);
+        }
+    };
+}
+
+macro_rules! debug_assert {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::debug_assert!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug_assert!($($x)*);
+        }
+    };
+}
+
+macro_rules! debug_assert_eq {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::debug_assert_eq!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug_assert_eq!($($x)*);
+        }
+    };
+}
+
+macro_rules! debug_assert_ne {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::debug_assert_ne!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug_assert_ne!($($x)*);
+        }
+    };
+}
+
+macro_rules! todo {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::todo!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::todo!($($x)*);
+        }
+    };
+}
+
+macro_rules! unreachable {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::unreachable!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::unreachable!($($x)*);
+        }
+    };
+}
+
+macro_rules! panic {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::panic!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::panic!($($x)*);
+        }
+    };
+}
+
+macro_rules! trace {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::trace!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::trace!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! debug {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::debug!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! info {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::info!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::info!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! warn {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::warn!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::warn!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! error {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::error!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::error!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+#[cfg(feature = "defmt")]
+macro_rules! unwrap {
+    ($($x:tt)*) => {
+        ::defmt::unwrap!($($x)*)
+    };
+}
+
+#[cfg(not(feature = "defmt"))]
+macro_rules! unwrap {
+    ($arg:expr) => {
+        match $crate::fmt::Try::into_result($arg) {
+            ::core::result::Result::Ok(t) => t,
+            ::core::result::Result::Err(e) => {
+                ::core::panic!("unwrap of `{}` failed: {:?}", ::core::stringify!($arg), e);
+            }
+        }
+    };
+    ($arg:expr, $($msg:expr),+ $(,)? ) => {
+        match $crate::fmt::Try::into_result($arg) {
+            ::core::result::Result::Ok(t) => t,
+            ::core::result::Result::Err(e) => {
+                ::core::panic!("unwrap of `{}` failed: {}: {:?}", ::core::stringify!($arg), ::core::format_args!($($msg,)*), e);
+            }
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct NoneError;
+
+pub trait Try {
+    type Ok;
+    type Error;
+    fn into_result(self) -> Result<Self::Ok, Self::Error>;
+}
+
+impl<T> Try for Option<T> {
+    type Ok = T;
+    type Error = NoneError;
+
+    #[inline]
+    fn into_result(self) -> Result<T, NoneError> {
+        self.ok_or(NoneError)
+    }
+}
+
+impl<T, E> Try for Result<T, E> {
+    type Ok = T;
+    type Error = E;
+
+    #[inline]
+    fn into_result(self) -> Self {
+        self
+    }
+}

embassy-boot/nrf/src/lib.rs

@@ -0,0 +1,203 @@
+#![no_std]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+mod fmt;
+
+pub use embassy_boot::{FirmwareUpdater, Partition, State, BOOT_MAGIC};
+use embassy_nrf::{
+    nvmc::{Nvmc, PAGE_SIZE},
+    peripherals::WDT,
+    wdt,
+};
+use embedded_storage::nor_flash::{ErrorType, NorFlash, ReadNorFlash};
+
+pub struct BootLoader {
+    boot: embassy_boot::BootLoader<PAGE_SIZE>,
+}
+
+impl BootLoader {
+    /// Create a new bootloader instance using parameters from linker script
+    pub fn default() -> Self {
+        extern "C" {
+            static __bootloader_state_start: u32;
+            static __bootloader_state_end: u32;
+            static __bootloader_active_start: u32;
+            static __bootloader_active_end: u32;
+            static __bootloader_dfu_start: u32;
+            static __bootloader_dfu_end: u32;
+        }
+
+        let active = unsafe {
+            Partition::new(
+                &__bootloader_active_start as *const u32 as usize,
+                &__bootloader_active_end as *const u32 as usize,
+            )
+        };
+        let dfu = unsafe {
+            Partition::new(
+                &__bootloader_dfu_start as *const u32 as usize,
+                &__bootloader_dfu_end as *const u32 as usize,
+            )
+        };
+        let state = unsafe {
+            Partition::new(
+                &__bootloader_state_start as *const u32 as usize,
+                &__bootloader_state_end as *const u32 as usize,
+            )
+        };
+
+        trace!("ACTIVE: 0x{:x} - 0x{:x}", active.from, active.to);
+        trace!("DFU: 0x{:x} - 0x{:x}", dfu.from, dfu.to);
+        trace!("STATE: 0x{:x} - 0x{:x}", state.from, state.to);
+
+        Self::new(active, dfu, state)
+    }
+
+    /// Create a new bootloader instance using the supplied partitions for active, dfu and state.
+    pub fn new(active: Partition, dfu: Partition, state: Partition) -> Self {
+        Self {
+            boot: embassy_boot::BootLoader::new(active, dfu, state),
+        }
+    }
+
+    /// Boots the application without softdevice mechanisms
+    pub fn prepare<F: NorFlash + ReadNorFlash>(&mut self, flash: &mut F) -> usize {
+        match self.boot.prepare_boot(flash) {
+            Ok(_) => self.boot.boot_address(),
+            Err(_) => panic!("boot prepare error!"),
+        }
+    }
+
+    #[cfg(not(feature = "softdevice"))]
+    pub unsafe fn load(&mut self, start: usize) -> ! {
+        let mut p = cortex_m::Peripherals::steal();
+        p.SCB.invalidate_icache();
+        p.SCB.vtor.write(start as u32);
+        cortex_m::asm::bootload(start as *const u32)
+    }
+
+    #[cfg(feature = "softdevice")]
+    pub unsafe fn load(&mut self, _app: usize) -> ! {
+        use nrf_softdevice_mbr as mbr;
+        const NRF_SUCCESS: u32 = 0;
+
+        // Address of softdevice which we'll forward interrupts to
+        let addr = 0x1000;
+        let mut cmd = mbr::sd_mbr_command_t {
+            command: mbr::NRF_MBR_COMMANDS_SD_MBR_COMMAND_IRQ_FORWARD_ADDRESS_SET,
+            params: mbr::sd_mbr_command_t__bindgen_ty_1 {
+                irq_forward_address_set: mbr::sd_mbr_command_irq_forward_address_set_t {
+                    address: addr,
+                },
+            },
+        };
+        let ret = mbr::sd_mbr_command(&mut cmd);
+        assert_eq!(ret, NRF_SUCCESS);
+
+        let msp = *(addr as *const u32);
+        let rv = *((addr + 4) as *const u32);
+
+        trace!("msp = {=u32:x}, rv = {=u32:x}", msp, rv);
+
+        core::arch::asm!(
+            "mrs {tmp}, CONTROL",
+            "bics {tmp}, {spsel}",
+            "msr CONTROL, {tmp}",
+            "isb",
+            "msr MSP, {msp}",
+            "mov lr, {new_lr}",
+            "bx {rv}",
+            // `out(reg) _` is not permitted in a `noreturn` asm! call,
+            // so instead use `in(reg) 0` and don't restore it afterwards.
+            tmp = in(reg) 0,
+            spsel = in(reg) 2,
+            new_lr = in(reg) 0xFFFFFFFFu32,
+            msp = in(reg) msp,
+            rv = in(reg) rv,
+            options(noreturn),
+        );
+    }
+}
+
+/// A flash implementation that wraps NVMC and will pet a watchdog when touching flash.
+pub struct WatchdogFlash<'d> {
+    flash: Nvmc<'d>,
+    wdt: wdt::WatchdogHandle,
+}
+
+impl<'d> WatchdogFlash<'d> {
+    /// Start a new watchdog with a given flash and WDT peripheral and a timeout
+    pub fn start(flash: Nvmc<'d>, wdt: WDT, timeout: u32) -> Self {
+        let mut config = wdt::Config::default();
+        config.timeout_ticks = 32768 * timeout; // timeout seconds
+        config.run_during_sleep = true;
+        config.run_during_debug_halt = false;
+        let (_wdt, [wdt]) = match wdt::Watchdog::try_new(wdt, config) {
+            Ok(x) => x,
+            Err(_) => {
+                // In case the watchdog is already running, just spin and let it expire, since
+                // we can't configure it anyway. This usually happens when we first program
+                // the device and the watchdog was previously active
+                info!("Watchdog already active with wrong config, waiting for it to timeout...");
+                loop {}
+            }
+        };
+        Self { flash, wdt }
+    }
+}
+
+impl<'d> ErrorType for WatchdogFlash<'d> {
+    type Error = <Nvmc<'d> as ErrorType>::Error;
+}
+
+impl<'d> NorFlash for WatchdogFlash<'d> {
+    const WRITE_SIZE: usize = <Nvmc<'d> as NorFlash>::WRITE_SIZE;
+    const ERASE_SIZE: usize = <Nvmc<'d> as NorFlash>::ERASE_SIZE;
+
+    fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
+        self.wdt.pet();
+        self.flash.erase(from, to)
+    }
+    fn write(&mut self, offset: u32, data: &[u8]) -> Result<(), Self::Error> {
+        self.wdt.pet();
+        self.flash.write(offset, data)
+    }
+}
+
+impl<'d> ReadNorFlash for WatchdogFlash<'d> {
+    const READ_SIZE: usize = <Nvmc<'d> as ReadNorFlash>::READ_SIZE;
+    fn read(&mut self, offset: u32, data: &mut [u8]) -> Result<(), Self::Error> {
+        self.wdt.pet();
+        self.flash.read(offset, data)
+    }
+    fn capacity(&self) -> usize {
+        self.flash.capacity()
+    }
+}
+
+pub mod updater {
+    use super::*;
+    pub fn new() -> embassy_boot::FirmwareUpdater {
+        extern "C" {
+            static __bootloader_state_start: u32;
+            static __bootloader_state_end: u32;
+            static __bootloader_dfu_start: u32;
+            static __bootloader_dfu_end: u32;
+        }
+
+        let dfu = unsafe {
+            Partition::new(
+                &__bootloader_dfu_start as *const u32 as usize,
+                &__bootloader_dfu_end as *const u32 as usize,
+            )
+        };
+        let state = unsafe {
+            Partition::new(
+                &__bootloader_state_start as *const u32 as usize,
+                &__bootloader_state_end as *const u32 as usize,
+            )
+        };
+        embassy_boot::FirmwareUpdater::new(dfu, state)
+    }
+}

embassy-boot/nrf/src/main.rs

@@ -0,0 +1,46 @@
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::{entry, exception};
+
+#[cfg(feature = "defmt")]
+use defmt_rtt as _;
+
+use embassy_boot_nrf::*;
+use embassy_nrf::nvmc::Nvmc;
+
+#[entry]
+fn main() -> ! {
+    let p = embassy_nrf::init(Default::default());
+    /*
+        for i in 0..10000000 {
+            cortex_m::asm::nop();
+        }
+    */
+
+    let mut bl = BootLoader::default();
+    let start = bl.prepare(&mut WatchdogFlash::start(Nvmc::new(p.NVMC), p.WDT, 5));
+    unsafe { bl.load(start) }
+}
+
+#[no_mangle]
+#[cfg_attr(target_os = "none", link_section = ".HardFault.user")]
+unsafe extern "C" fn HardFault() {
+    cortex_m::peripheral::SCB::sys_reset();
+}
+
+#[exception]
+unsafe fn DefaultHandler(_: i16) -> ! {
+    const SCB_ICSR: *const u32 = 0xE000_ED04 as *const u32;
+    let irqn = core::ptr::read_volatile(SCB_ICSR) as u8 as i16 - 16;
+
+    panic!("DefaultHandler #{:?}", irqn);
+}
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    unsafe {
+        core::arch::asm!("udf #0");
+        core::hint::unreachable_unchecked();
+    }
+}