Merge remote-tracking branch 'upstream/master' into incremental-hash

5 files changed, 253 insertions, 179 deletions

diff --git a/embassy-boot/boot/src/boot_loader.rs b/embassy-boot/boot/src/boot_loader.rs
index e2e361e3c..9d047f778 100644
--- a/embassy-boot/boot/src/boot_loader.rs
+++ b/embassy-boot/boot/src/boot_loader.rs
@@ -31,7 +31,7 @@ where
 }
 
 /// Extension of the embedded-storage flash type information with block size and erase value.
-pub trait Flash: NorFlash + ReadNorFlash {
+pub trait Flash: NorFlash {
     /// The block size that should be used when writing to flash. For most builtin flashes, this is the same as the erase
     /// size of the flash, but for external QSPI flash modules, this can be lower.
     const BLOCK_SIZE: usize;
@@ -60,9 +60,11 @@ pub trait FlashConfig {
 /// different page sizes and flash write sizes.
 pub struct BootLoader {
     // Page with current state of bootloader. The state partition has the following format:
-    // | Range          | Description                                                                      |
-    // | 0 - WRITE_SIZE | Magic indicating bootloader state. BOOT_MAGIC means boot, SWAP_MAGIC means swap. |
-    // | WRITE_SIZE - N | Progress index used while swapping or reverting                                  |
+    // All ranges are in multiples of WRITE_SIZE bytes.
+    // | Range    | Description                                                                      |
+    // | 0..1     | Magic indicating bootloader state. BOOT_MAGIC means boot, SWAP_MAGIC means swap. |
+    // | 1..2     | Progress validity. ERASE_VALUE means valid, !ERASE_VALUE means invalid.          |
+    // | 2..2 + N | Progress index used while swapping or reverting                                  |
     state: Partition,
     // Location of the partition which will be booted from
     active: Partition,
@@ -192,12 +194,17 @@ impl BootLoader {
                 trace!("Reverting");
                 self.revert(p, magic, page)?;
 
-                // Overwrite magic and reset progress
                 let state_flash = p.state();
+
+                // Invalidate progress
                 magic.fill(!P::STATE::ERASE_VALUE);
-                self.state.write_blocking(state_flash, 0, magic)?;
+                self.state
+                    .write_blocking(state_flash, P::STATE::WRITE_SIZE as u32, magic)?;
+
+                // Clear magic and progress
                 self.state.wipe_blocking(state_flash)?;
 
+                // Set magic
                 magic.fill(BOOT_MAGIC);
                 self.state.write_blocking(state_flash, 0, magic)?;
             }
@@ -215,28 +222,34 @@ impl BootLoader {
 
     fn current_progress<P: FlashConfig>(&mut self, config: &mut P, aligned: &mut [u8]) -> Result<usize, BootError> {
         let write_size = aligned.len();
-        let max_index = ((self.state.len() - write_size) / write_size) - 1;
+        let max_index = ((self.state.len() - write_size) / write_size) - 2;
         aligned.fill(!P::STATE::ERASE_VALUE);
 
         let state_flash = config.state();
-        for i in 0..max_index {
+
+        self.state
+            .read_blocking(state_flash, P::STATE::WRITE_SIZE as u32, aligned)?;
+        if aligned.iter().any(|&b| b != P::STATE::ERASE_VALUE) {
+            // Progress is invalid
+            return Ok(max_index);
+        }
+
+        for index in 0..max_index {
             self.state
-                .read_blocking(state_flash, (write_size + i * write_size) as u32, aligned)?;
+                .read_blocking(state_flash, (2 + index) as u32 * P::STATE::WRITE_SIZE as u32, aligned)?;
 
             if aligned.iter().any(|&b| b == P::STATE::ERASE_VALUE) {
-                return Ok(i);
+                return Ok(index);
             }
         }
         Ok(max_index)
     }
 
-    fn update_progress<P: FlashConfig>(&mut self, idx: usize, p: &mut P, magic: &mut [u8]) -> Result<(), BootError> {
-        let write_size = magic.len();
-
+    fn update_progress<P: FlashConfig>(&mut self, index: usize, p: &mut P, magic: &mut [u8]) -> Result<(), BootError> {
         let aligned = magic;
         aligned.fill(!P::STATE::ERASE_VALUE);
         self.state
-            .write_blocking(p.state(), (write_size + idx * write_size) as u32, aligned)?;
+            .write_blocking(p.state(), (2 + index) as u32 * P::STATE::WRITE_SIZE as u32, aligned)?;
         Ok(())
     }
 
@@ -360,7 +373,7 @@ fn assert_partitions(active: Partition, dfu: Partition, state: Partition, page_s
     assert_eq!(active.len() % page_size, 0);
     assert_eq!(dfu.len() % page_size, 0);
     assert!(dfu.len() - active.len() >= page_size);
-    assert!(2 * (active.len() / page_size) <= (state.len() - write_size) / write_size);
+    assert!(2 + 2 * (active.len() / page_size) <= state.len() / write_size);
 }
 
 /// A flash wrapper implementing the Flash and embedded_storage traits.
diff --git a/embassy-boot/boot/src/firmware_updater.rs b/embassy-boot/boot/src/firmware_updater.rs
index 2d1b26980..819e20201 100644
--- a/embassy-boot/boot/src/firmware_updater.rs
+++ b/embassy-boot/boot/src/firmware_updater.rs
@@ -234,11 +234,24 @@ impl FirmwareUpdater {
         self.state.read(state_flash, 0, aligned).await?;
 
         if aligned.iter().any(|&b| b != magic) {
-            aligned.fill(0);
+            // Read progress validity
+            self.state.read(state_flash, F::WRITE_SIZE as u32, aligned).await?;
+
+            // FIXME: Do not make this assumption.
+            const STATE_ERASE_VALUE: u8 = 0xFF;
+
+            if aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
+                // The current progress validity marker is invalid
+            } else {
+                // Invalidate progress
+                aligned.fill(!STATE_ERASE_VALUE);
+                self.state.write(state_flash, F::WRITE_SIZE as u32, aligned).await?;
+            }
 
-            self.state.write(state_flash, 0, aligned).await?;
+            // Clear magic and progress
             self.state.wipe(state_flash).await?;
 
+            // Set magic
             aligned.fill(magic);
             self.state.write(state_flash, 0, aligned).await?;
         }
@@ -441,11 +454,24 @@ impl FirmwareUpdater {
         self.state.read_blocking(state_flash, 0, aligned)?;
 
         if aligned.iter().any(|&b| b != magic) {
-            aligned.fill(0);
+            // Read progress validity
+            self.state.read_blocking(state_flash, F::WRITE_SIZE as u32, aligned)?;
+
+            // FIXME: Do not make this assumption.
+            const STATE_ERASE_VALUE: u8 = 0xFF;
+
+            if aligned.iter().any(|&b| b != STATE_ERASE_VALUE) {
+                // The current progress validity marker is invalid
+            } else {
+                // Invalidate progress
+                aligned.fill(!STATE_ERASE_VALUE);
+                self.state.write_blocking(state_flash, F::WRITE_SIZE as u32, aligned)?;
+            }
 
-            self.state.write_blocking(state_flash, 0, aligned)?;
+            // Clear magic and progress
             self.state.wipe_blocking(state_flash)?;
 
+            // Set magic
             aligned.fill(magic);
             self.state.write_blocking(state_flash, 0, aligned)?;
         }
diff --git a/embassy-boot/boot/src/lib.rs b/embassy-boot/boot/src/lib.rs
index da9055476..d4078f1cb 100644
--- a/embassy-boot/boot/src/lib.rs
+++ b/embassy-boot/boot/src/lib.rs
@@ -8,6 +8,7 @@ mod fmt;
 mod boot_loader;
 mod digest_adapters;
 mod firmware_updater;
+mod mem_flash;
 mod partition;
 
 pub use boot_loader::{BootError, BootFlash, BootLoader, Flash, FlashConfig, MultiFlashConfig, SingleFlashConfig};
@@ -45,13 +46,10 @@ impl<const N: usize> AsMut<[u8]> for AlignedBuffer<N> {
 
 #[cfg(test)]
 mod tests {
-    use core::convert::Infallible;
-
-    use embedded_storage::nor_flash::{ErrorType, NorFlash, ReadNorFlash};
-    use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};
     use futures::executor::block_on;
 
     use super::*;
+    use crate::mem_flash::MemFlash;
 
     /*
     #[test]
@@ -74,8 +72,8 @@ mod tests {
         const ACTIVE: Partition = Partition::new(4096, 61440);
         const DFU: Partition = Partition::new(61440, 122880);
 
-        let mut flash = MemFlash::<131072, 4096, 4>([0xff; 131072]);
-        flash.0[0..4].copy_from_slice(&[BOOT_MAGIC; 4]);
+        let mut flash = MemFlash::<131072, 4096, 4>::default();
+        flash.mem[0..4].copy_from_slice(&[BOOT_MAGIC; 4]);
         let mut flash = SingleFlashConfig::new(&mut flash);
 
         let mut bootloader: BootLoader = BootLoader::new(ACTIVE, DFU, STATE);
@@ -94,14 +92,14 @@ mod tests {
         const STATE: Partition = Partition::new(0, 4096);
         const ACTIVE: Partition = Partition::new(4096, 61440);
         const DFU: Partition = Partition::new(61440, 122880);
-        let mut flash = MemFlash::<131072, 4096, 4>([0xff; 131072]);
+        let mut flash = MemFlash::<131072, 4096, 4>::random();
 
         let original: [u8; ACTIVE.len()] = [rand::random::<u8>(); ACTIVE.len()];
         let update: [u8; DFU.len()] = [rand::random::<u8>(); DFU.len()];
         let mut aligned = [0; 4];
 
         for i in ACTIVE.from..ACTIVE.to {
-            flash.0[i] = original[i - ACTIVE.from];
+            flash.mem[i] = original[i - ACTIVE.from];
         }
 
         let mut bootloader: BootLoader = BootLoader::new(ACTIVE, DFU, STATE);
@@ -123,12 +121,12 @@ mod tests {
         );
 
         for i in ACTIVE.from..ACTIVE.to {
-            assert_eq!(flash.0[i], update[i - ACTIVE.from], "Index {}", i);
+            assert_eq!(flash.mem[i], update[i - ACTIVE.from], "Index {}", i);
         }
 
         // First DFU page is untouched
         for i in DFU.from + 4096..DFU.to {
-            assert_eq!(flash.0[i], original[i - DFU.from - 4096], "Index {}", i);
+            assert_eq!(flash.mem[i], original[i - DFU.from - 4096], "Index {}", i);
         }
 
         // Running again should cause a revert
@@ -140,12 +138,12 @@ mod tests {
         );
 
         for i in ACTIVE.from..ACTIVE.to {
-            assert_eq!(flash.0[i], original[i - ACTIVE.from], "Index {}", i);
+            assert_eq!(flash.mem[i], original[i - ACTIVE.from], "Index {}", i);
         }
 
         // Last page is untouched
         for i in DFU.from..DFU.to - 4096 {
-            assert_eq!(flash.0[i], update[i - DFU.from], "Index {}", i);
+            assert_eq!(flash.mem[i], update[i - DFU.from], "Index {}", i);
         }
 
         // Mark as booted
@@ -165,16 +163,16 @@ mod tests {
         const ACTIVE: Partition = Partition::new(4096, 16384);
         const DFU: Partition = Partition::new(0, 16384);
 
-        let mut active = MemFlash::<16384, 4096, 8>([0xff; 16384]);
-        let mut dfu = MemFlash::<16384, 2048, 8>([0xff; 16384]);
-        let mut state = MemFlash::<4096, 128, 4>([0xff; 4096]);
+        let mut active = MemFlash::<16384, 4096, 8>::random();
+        let mut dfu = MemFlash::<16384, 2048, 8>::random();
+        let mut state = MemFlash::<4096, 128, 4>::random();
         let mut aligned = [0; 4];
 
         let original: [u8; ACTIVE.len()] = [rand::random::<u8>(); ACTIVE.len()];
         let update: [u8; DFU.len()] = [rand::random::<u8>(); DFU.len()];
 
         for i in ACTIVE.from..ACTIVE.to {
-            active.0[i] = original[i - ACTIVE.from];
+            active.mem[i] = original[i - ACTIVE.from];
         }
 
         let mut updater = FirmwareUpdater::new(DFU, STATE);
@@ -202,12 +200,12 @@ mod tests {
         );
 
         for i in ACTIVE.from..ACTIVE.to {
-            assert_eq!(active.0[i], update[i - ACTIVE.from], "Index {}", i);
+            assert_eq!(active.mem[i], update[i - ACTIVE.from], "Index {}", i);
         }
 
         // First DFU page is untouched
         for i in DFU.from + 4096..DFU.to {
-            assert_eq!(dfu.0[i], original[i - DFU.from - 4096], "Index {}", i);
+            assert_eq!(dfu.mem[i], original[i - DFU.from - 4096], "Index {}", i);
         }
     }
 
@@ -219,15 +217,15 @@ mod tests {
         const DFU: Partition = Partition::new(0, 16384);
 
         let mut aligned = [0; 4];
-        let mut active = MemFlash::<16384, 2048, 4>([0xff; 16384]);
-        let mut dfu = MemFlash::<16384, 4096, 8>([0xff; 16384]);
-        let mut state = MemFlash::<4096, 128, 4>([0xff; 4096]);
+        let mut active = MemFlash::<16384, 2048, 4>::random();
+        let mut dfu = MemFlash::<16384, 4096, 8>::random();
+        let mut state = MemFlash::<4096, 128, 4>::random();
 
         let original: [u8; ACTIVE.len()] = [rand::random::<u8>(); ACTIVE.len()];
         let update: [u8; DFU.len()] = [rand::random::<u8>(); DFU.len()];
 
         for i in ACTIVE.from..ACTIVE.to {
-            active.0[i] = original[i - ACTIVE.from];
+            active.mem[i] = original[i - ACTIVE.from];
         }
 
         let mut updater = FirmwareUpdater::new(DFU, STATE);
@@ -254,12 +252,12 @@ mod tests {
         );
 
         for i in ACTIVE.from..ACTIVE.to {
-            assert_eq!(active.0[i], update[i - ACTIVE.from], "Index {}", i);
+            assert_eq!(active.mem[i], update[i - ACTIVE.from], "Index {}", i);
         }
 
         // First DFU page is untouched
         for i in DFU.from + 4096..DFU.to {
-            assert_eq!(dfu.0[i], original[i - DFU.from - 4096], "Index {}", i);
+            assert_eq!(dfu.mem[i], original[i - DFU.from - 4096], "Index {}", i);
         }
     }
 
@@ -289,13 +287,13 @@ mod tests {
 
         const STATE: Partition = Partition::new(0, 4096);
         const DFU: Partition = Partition::new(4096, 8192);
-        let mut flash = MemFlash::<8192, 4096, 4>([0xff; 8192]);
+        let mut flash = MemFlash::<8192, 4096, 4>::default();
 
         let firmware_len = firmware.len();
 
         let mut write_buf = [0; 4096];
         write_buf[0..firmware_len].copy_from_slice(firmware);
-        NorFlash::write(&mut flash, DFU.from as u32, &write_buf).unwrap();
+        DFU.write_blocking(&mut flash, 0, &write_buf).unwrap();
 
         // On with the test
 
@@ -312,113 +310,4 @@ mod tests {
         ))
         .is_ok());
     }
-
-    pub struct MemFlash<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize>(pub [u8; SIZE]);
-
-    impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> NorFlash
-        for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
-    {
-        const WRITE_SIZE: usize = WRITE_SIZE;
-        const ERASE_SIZE: usize = ERASE_SIZE;
-        fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
-            let from = from as usize;
-            let to = to as usize;
-            assert!(from % ERASE_SIZE == 0);
-            assert!(to % ERASE_SIZE == 0, "To: {}, erase size: {}", to, ERASE_SIZE);
-            for i in from..to {
-                self.0[i] = 0xFF;
-            }
-            Ok(())
-        }
-
-        fn write(&mut self, offset: u32, data: &[u8]) -> Result<(), Self::Error> {
-            assert!(data.len() % WRITE_SIZE == 0);
-            assert!(offset as usize % WRITE_SIZE == 0);
-            assert!(offset as usize + data.len() <= SIZE);
-
-            self.0[offset as usize..offset as usize + data.len()].copy_from_slice(data);
-
-            Ok(())
-        }
-    }
-
-    impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> ErrorType
-        for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
-    {
-        type Error = Infallible;
-    }
-
-    impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> ReadNorFlash
-        for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
-    {
-        const READ_SIZE: usize = 1;
-
-        fn read(&mut self, offset: u32, buf: &mut [u8]) -> Result<(), Self::Error> {
-            let len = buf.len();
-            buf[..].copy_from_slice(&self.0[offset as usize..offset as usize + len]);
-            Ok(())
-        }
-
-        fn capacity(&self) -> usize {
-            SIZE
-        }
-    }
-
-    impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> super::Flash
-        for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
-    {
-        const BLOCK_SIZE: usize = ERASE_SIZE;
-        const ERASE_VALUE: u8 = 0xFF;
-    }
-
-    impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncReadNorFlash
-        for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
-    {
-        const READ_SIZE: usize = 1;
-
-        async fn read(&mut self, offset: u32, buf: &mut [u8]) -> Result<(), Self::Error> {
-            let len = buf.len();
-            buf[..].copy_from_slice(&self.0[offset as usize..offset as usize + len]);
-            Ok(())
-        }
-
-        fn capacity(&self) -> usize {
-            SIZE
-        }
-    }
-
-    impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncNorFlash
-        for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
-    {
-        const WRITE_SIZE: usize = WRITE_SIZE;
-        const ERASE_SIZE: usize = ERASE_SIZE;
-
-        async fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
-            let from = from as usize;
-            let to = to as usize;
-            assert!(from % ERASE_SIZE == 0);
-            assert!(to % ERASE_SIZE == 0);
-            for i in from..to {
-                self.0[i] = 0xFF;
-            }
-            Ok(())
-        }
-
-        async fn write(&mut self, offset: u32, data: &[u8]) -> Result<(), Self::Error> {
-            info!("Writing {} bytes to 0x{:x}", data.len(), offset);
-            assert!(data.len() % WRITE_SIZE == 0);
-            assert!(offset as usize % WRITE_SIZE == 0);
-            assert!(
-                offset as usize + data.len() <= SIZE,
-                "OFFSET: {}, LEN: {}, FLASH SIZE: {}",
-                offset,
-                data.len(),
-                SIZE
-            );
-
-            self.0[offset as usize..offset as usize + data.len()].copy_from_slice(data);
-
-            Ok(())
-        }
-    }
 }
diff --git a/embassy-boot/boot/src/mem_flash.rs b/embassy-boot/boot/src/mem_flash.rs
new file mode 100644
index 000000000..828aad9d9
--- /dev/null
+++ b/embassy-boot/boot/src/mem_flash.rs
@@ -0,0 +1,156 @@
+#![allow(unused)]
+
+use core::ops::{Bound, Range, RangeBounds};
+
+use embedded_storage::nor_flash::{ErrorType, NorFlash, NorFlashError, NorFlashErrorKind, ReadNorFlash};
+use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};
+
+use crate::Flash;
+
+pub struct MemFlash<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> {
+    pub mem: [u8; SIZE],
+    pub pending_write_successes: Option<usize>,
+}
+
+#[derive(Debug)]
+pub struct MemFlashError;
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE> {
+    pub const fn new(fill: u8) -> Self {
+        Self {
+            mem: [fill; SIZE],
+            pending_write_successes: None,
+        }
+    }
+
+    #[cfg(test)]
+    pub fn random() -> Self {
+        let mut mem = [0; SIZE];
+        for byte in mem.iter_mut() {
+            *byte = rand::random::<u8>();
+        }
+        Self {
+            mem,
+            pending_write_successes: None,
+        }
+    }
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> Default
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    fn default() -> Self {
+        Self::new(0xFF)
+    }
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> Flash
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    const BLOCK_SIZE: usize = ERASE_SIZE;
+    const ERASE_VALUE: u8 = 0xFF;
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> ErrorType
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    type Error = MemFlashError;
+}
+
+impl NorFlashError for MemFlashError {
+    fn kind(&self) -> NorFlashErrorKind {
+        NorFlashErrorKind::Other
+    }
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> ReadNorFlash
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    const READ_SIZE: usize = 1;
+
+    fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
+        let len = bytes.len();
+        bytes.copy_from_slice(&self.mem[offset as usize..offset as usize + len]);
+        Ok(())
+    }
+
+    fn capacity(&self) -> usize {
+        SIZE
+    }
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> NorFlash
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    const WRITE_SIZE: usize = WRITE_SIZE;
+    const ERASE_SIZE: usize = ERASE_SIZE;
+
+    fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
+        let from = from as usize;
+        let to = to as usize;
+        assert!(from % ERASE_SIZE == 0);
+        assert!(to % ERASE_SIZE == 0, "To: {}, erase size: {}", to, ERASE_SIZE);
+        for i in from..to {
+            self.mem[i] = 0xFF;
+        }
+        Ok(())
+    }
+
+    fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
+        let offset = offset as usize;
+        assert!(bytes.len() % WRITE_SIZE == 0);
+        assert!(offset % WRITE_SIZE == 0);
+        assert!(offset + bytes.len() <= SIZE);
+
+        if let Some(pending_successes) = self.pending_write_successes {
+            if pending_successes > 0 {
+                self.pending_write_successes = Some(pending_successes - 1);
+            } else {
+                return Err(MemFlashError);
+            }
+        }
+
+        for ((offset, mem_byte), new_byte) in self
+            .mem
+            .iter_mut()
+            .enumerate()
+            .skip(offset)
+            .take(bytes.len())
+            .zip(bytes)
+        {
+            assert_eq!(0xFF, *mem_byte, "Offset {} is not erased", offset);
+            *mem_byte = *new_byte;
+        }
+
+        Ok(())
+    }
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncReadNorFlash
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    const READ_SIZE: usize = 1;
+
+    async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
+        <Self as ReadNorFlash>::read(self, offset, bytes)
+    }
+
+    fn capacity(&self) -> usize {
+        <Self as ReadNorFlash>::capacity(self)
+    }
+}
+
+impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncNorFlash
+    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
+{
+    const WRITE_SIZE: usize = WRITE_SIZE;
+    const ERASE_SIZE: usize = ERASE_SIZE;
+
+    async fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
+        <Self as NorFlash>::erase(self, from, to)
+    }
+
+    async fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
+        <Self as NorFlash>::write(self, offset, bytes)
+    }
+}
diff --git a/embassy-boot/boot/src/partition.rs b/embassy-boot/boot/src/partition.rs
index 3ccd4dd76..ac6b0ed0f 100644
--- a/embassy-boot/boot/src/partition.rs
+++ b/embassy-boot/boot/src/partition.rs
@@ -24,7 +24,7 @@ impl Partition {
     }
 
     /// Read from the partition on the provided flash
-    pub(crate) async fn read<F: AsyncReadNorFlash>(
+    pub async fn read<F: AsyncReadNorFlash>(
         &self,
         flash: &mut F,
         offset: u32,
@@ -35,12 +35,7 @@ impl Partition {
     }
 
     /// Write to the partition on the provided flash
-    pub(crate) async fn write<F: AsyncNorFlash>(
-        &self,
-        flash: &mut F,
-        offset: u32,
-        bytes: &[u8],
-    ) -> Result<(), F::Error> {
+    pub async fn write<F: AsyncNorFlash>(&self, flash: &mut F, offset: u32, bytes: &[u8]) -> Result<(), F::Error> {
         let offset = self.from as u32 + offset;
         flash.write(offset, bytes).await?;
         trace!("Wrote from 0x{:x} len {}", offset, bytes.len());
@@ -48,7 +43,7 @@ impl Partition {
     }
 
     /// Erase part of the partition on the provided flash
-    pub(crate) async fn erase<F: AsyncNorFlash>(&self, flash: &mut F, from: u32, to: u32) -> Result<(), F::Error> {
+    pub async fn erase<F: AsyncNorFlash>(&self, flash: &mut F, from: u32, to: u32) -> Result<(), F::Error> {
         let from = self.from as u32 + from;
         let to = self.from as u32 + to;
         flash.erase(from, to).await?;
@@ -66,18 +61,13 @@ impl Partition {
     }
 
     /// Read from the partition on the provided flash
-    pub(crate) fn read_blocking<F: ReadNorFlash>(
-        &self,
-        flash: &mut F,
-        offset: u32,
-        bytes: &mut [u8],
-    ) -> Result<(), F::Error> {
+    pub fn read_blocking<F: ReadNorFlash>(&self, flash: &mut F, offset: u32, bytes: &mut [u8]) -> Result<(), F::Error> {
         let offset = self.from as u32 + offset;
         flash.read(offset, bytes)
     }
 
     /// Write to the partition on the provided flash
-    pub(crate) fn write_blocking<F: NorFlash>(&self, flash: &mut F, offset: u32, bytes: &[u8]) -> Result<(), F::Error> {
+    pub fn write_blocking<F: NorFlash>(&self, flash: &mut F, offset: u32, bytes: &[u8]) -> Result<(), F::Error> {
         let offset = self.from as u32 + offset;
         flash.write(offset, bytes)?;
         trace!("Wrote from 0x{:x} len {}", offset, bytes.len());
@@ -85,7 +75,7 @@ impl Partition {
     }
 
     /// Erase part of the partition on the provided flash
-    pub(crate) fn erase_blocking<F: NorFlash>(&self, flash: &mut F, from: u32, to: u32) -> Result<(), F::Error> {
+    pub fn erase_blocking<F: NorFlash>(&self, flash: &mut F, from: u32, to: u32) -> Result<(), F::Error> {
         let from = self.from as u32 + from;
         let to = self.from as u32 + to;
         flash.erase(from, to)?;
@@ -105,45 +95,45 @@ impl Partition {
 
 #[cfg(test)]
 mod tests {
-    use crate::tests::MemFlash;
+    use crate::mem_flash::MemFlash;
     use crate::Partition;
 
     #[test]
     fn can_erase() {
-        let mut flash = MemFlash::<1024, 64, 4>([0x00; 1024]);
+        let mut flash = MemFlash::<1024, 64, 4>::new(0x00);
         let partition = Partition::new(256, 512);
 
         partition.erase_blocking(&mut flash, 64, 192).unwrap();
 
-        for (index, byte) in flash.0.iter().copied().enumerate().take(256 + 64) {
+        for (index, byte) in flash.mem.iter().copied().enumerate().take(256 + 64) {
             assert_eq!(0x00, byte, "Index {}", index);
         }
 
-        for (index, byte) in flash.0.iter().copied().enumerate().skip(256 + 64).take(128) {
+        for (index, byte) in flash.mem.iter().copied().enumerate().skip(256 + 64).take(128) {
             assert_eq!(0xFF, byte, "Index {}", index);
         }
 
-        for (index, byte) in flash.0.iter().copied().enumerate().skip(256 + 64 + 128) {
+        for (index, byte) in flash.mem.iter().copied().enumerate().skip(256 + 64 + 128) {
             assert_eq!(0x00, byte, "Index {}", index);
         }
     }
 
     #[test]
     fn can_wipe() {
-        let mut flash = MemFlash::<1024, 64, 4>([0x00; 1024]);
+        let mut flash = MemFlash::<1024, 64, 4>::new(0x00);
         let partition = Partition::new(256, 512);
 
         partition.wipe_blocking(&mut flash).unwrap();
 
-        for (index, byte) in flash.0.iter().copied().enumerate().take(256) {
+        for (index, byte) in flash.mem.iter().copied().enumerate().take(256) {
             assert_eq!(0x00, byte, "Index {}", index);
         }
 
-        for (index, byte) in flash.0.iter().copied().enumerate().skip(256).take(256) {
+        for (index, byte) in flash.mem.iter().copied().enumerate().skip(256).take(256) {
             assert_eq!(0xFF, byte, "Index {}", index);
         }
 
-        for (index, byte) in flash.0.iter().copied().enumerate().skip(512) {
+        for (index, byte) in flash.mem.iter().copied().enumerate().skip(512) {
             assert_eq!(0x00, byte, "Index {}", index);
         }
     }