Merge pull request #3349 from embassy-rs/e-b-introduce-reverted-magic

Add revert state in embassy-boot

embassy-boot/src/boot_loader.rs

@@ -5,7 +5,7 @@ use embassy_sync::blocking_mutex::raw::NoopRawMutex;
 use embassy_sync::blocking_mutex::Mutex;
 use embedded_storage::nor_flash::{NorFlash, NorFlashError, NorFlashErrorKind};
 
-use crate::{State, BOOT_MAGIC, DFU_DETACH_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC};
+use crate::{State, DFU_DETACH_MAGIC, REVERT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC};
 
 /// Errors returned by bootloader
 #[derive(PartialEq, Eq, Debug)]
@@ -276,7 +276,7 @@ impl<ACTIVE: NorFlash, DFU: NorFlash, STATE: NorFlash> BootLoader<ACTIVE, DFU, S
                 self.state.erase(0, self.state.capacity() as u32)?;
 
                 // Set magic
-                state_word.fill(BOOT_MAGIC);
+                state_word.fill(REVERT_MAGIC);
                 self.state.write(0, state_word)?;
             }
         }
@@ -411,6 +411,8 @@ impl<ACTIVE: NorFlash, DFU: NorFlash, STATE: NorFlash> BootLoader<ACTIVE, DFU, S
             Ok(State::Swap)
         } else if !state_word.iter().any(|&b| b != DFU_DETACH_MAGIC) {
             Ok(State::DfuDetach)
+        } else if !state_word.iter().any(|&b| b != REVERT_MAGIC) {
+            Ok(State::Revert)
         } else {
             Ok(State::Boot)
         }

embassy-boot/src/firmware_updater/asynch.rs

@@ -289,7 +289,8 @@ impl<'d, STATE: NorFlash> FirmwareState<'d, STATE> {
 
     // Make sure we are running a booted firmware to avoid reverting to a bad state.
     async fn verify_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
-        if self.get_state().await? == State::Boot {
+        let state = self.get_state().await?;
+        if state == State::Boot || state == State::DfuDetach || state == State::Revert {
             Ok(())
         } else {
             Err(FirmwareUpdaterError::BadState)
@@ -303,12 +304,7 @@ impl<'d, STATE: NorFlash> FirmwareState<'d, STATE> {
     /// `mark_booted`.
     pub async fn get_state(&mut self) -> Result<State, FirmwareUpdaterError> {
         self.state.read(0, &mut self.aligned).await?;
-
-        if !self.aligned.iter().any(|&b| b != SWAP_MAGIC) {
-            Ok(State::Swap)
-        } else {
-            Ok(State::Boot)
-        }
+        Ok(State::from(&self.aligned))
     }
 
     /// Mark to trigger firmware swap on next boot.

embassy-boot/src/firmware_updater/blocking.rs

@@ -324,7 +324,8 @@ impl<'d, STATE: NorFlash> BlockingFirmwareState<'d, STATE> {
 
     // Make sure we are running a booted firmware to avoid reverting to a bad state.
     fn verify_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
-        if self.get_state()? == State::Boot || self.get_state()? == State::DfuDetach {
+        let state = self.get_state()?;
+        if state == State::Boot || state == State::DfuDetach || state == State::Revert {
             Ok(())
         } else {
             Err(FirmwareUpdaterError::BadState)
@@ -338,14 +339,7 @@ impl<'d, STATE: NorFlash> BlockingFirmwareState<'d, STATE> {
     /// `mark_booted`.
     pub fn get_state(&mut self) -> Result<State, FirmwareUpdaterError> {
         self.state.read(0, &mut self.aligned)?;
-
-        if !self.aligned.iter().any(|&b| b != SWAP_MAGIC) {
-            Ok(State::Swap)
-        } else if !self.aligned.iter().any(|&b| b != DFU_DETACH_MAGIC) {
-            Ok(State::DfuDetach)
-        } else {
-            Ok(State::Boot)
-        }
+        Ok(State::from(&self.aligned))
     }
 
     /// Mark to trigger firmware swap on next boot.

embassy-boot/src/lib.rs

@@ -25,6 +25,7 @@ pub use firmware_updater::{
     FirmwareUpdaterError,
 };
 
+pub(crate) const REVERT_MAGIC: u8 = 0xC0;
 pub(crate) const BOOT_MAGIC: u8 = 0xD0;
 pub(crate) const SWAP_MAGIC: u8 = 0xF0;
 pub(crate) const DFU_DETACH_MAGIC: u8 = 0xE0;
@@ -37,10 +38,30 @@ pub enum State {
     Boot,
     /// Bootloader has swapped the active partition with the dfu partition and will attempt boot.
     Swap,
+    /// Bootloader has reverted the active partition with the dfu partition and will attempt boot.
+    Revert,
     /// Application has received a request to reboot into DFU mode to apply an update.
     DfuDetach,
 }
 
+impl<T> From<T> for State
+where
+    T: AsRef<[u8]>,
+{
+    fn from(magic: T) -> State {
+        let magic = magic.as_ref();
+        if !magic.iter().any(|&b| b != SWAP_MAGIC) {
+            State::Swap
+        } else if !magic.iter().any(|&b| b != REVERT_MAGIC) {
+            State::Revert
+        } else if !magic.iter().any(|&b| b != DFU_DETACH_MAGIC) {
+            State::DfuDetach
+        } else {
+            State::Boot
+        }
+    }
+}
+
 /// Buffer aligned to 32 byte boundary, largest known alignment requirement for embassy-boot.
 #[repr(align(32))]
 pub struct AlignedBuffer<const N: usize>(pub [u8; N]);
@@ -157,6 +178,9 @@ mod tests {
         // Running again should cause a revert
         assert_eq!(State::Swap, bootloader.prepare_boot(&mut page).unwrap());
 
+        // Next time we know it was reverted
+        assert_eq!(State::Revert, bootloader.prepare_boot(&mut page).unwrap());
+
         let mut read_buf = [0; FIRMWARE_SIZE];
         flash.active().read(0, &mut read_buf).unwrap();
         assert_eq!(ORIGINAL, read_buf);

examples/boot/application/nrf/build.rs

@@ -31,4 +31,7 @@ fn main() {
 
     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/nrf/src/bin/a.rs

@@ -2,6 +2,9 @@
 #![no_main]
 #![macro_use]
 
+#[cfg(feature = "defmt")]
+use defmt_rtt as _;
+use embassy_boot::State;
 use embassy_boot_nrf::{FirmwareUpdater, FirmwareUpdaterConfig};
 use embassy_embedded_hal::adapter::BlockingAsync;
 use embassy_executor::Spawner;
@@ -22,6 +25,7 @@ async fn main(_spawner: Spawner) {
 
     let mut button = Input::new(p.P0_11, Pull::Up);
     let mut led = Output::new(p.P0_13, Level::Low, OutputDrive::Standard);
+    let mut led_reverted = Output::new(p.P0_14, Level::High, OutputDrive::Standard);
 
     //let mut led = Output::new(p.P1_10, Level::Low, OutputDrive::Standard);
     //let mut button = Input::new(p.P1_02, Pull::Up);
@@ -53,6 +57,13 @@ async fn main(_spawner: Spawner) {
     let config = FirmwareUpdaterConfig::from_linkerfile(&nvmc, &nvmc);
     let mut magic = [0; 4];
     let mut updater = FirmwareUpdater::new(config, &mut magic);
+    let state = updater.get_state().await.unwrap();
+    if state == State::Revert {
+        led_reverted.set_low();
+    } else {
+        led_reverted.set_high();
+    }
+
     loop {
         led.set_low();
         button.wait_for_any_edge().await;