Let FlashLayout and FlashRegion depends on a Blocking/Async mode generic

embassy-stm32/Cargo.toml

@@ -69,7 +69,6 @@ cfg-if = "1.0.0"
 embedded-io = { version = "0.4.0", features = ["async"], optional = true }
 chrono = { version = "^0.4", default-features = false, optional = true}
 bit_field = "0.10.2"
-paste = "1.0.12"
 
 [dev-dependencies]
 critical-section = { version = "1.1", features = ["std"] }

embassy-stm32/build.rs

@@ -213,7 +213,7 @@ fn main() {
         let region_type = format_ident!("{}", get_flash_region_type_name(region.name));
         flash_regions.extend(quote! {
             #[cfg(flash)]
-            pub struct #region_type<'d>(pub &'static crate::flash::FlashRegion, pub(crate) embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>,);
+            pub struct #region_type<'d, MODE>(pub &'static crate::flash::FlashRegion, pub(crate) embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>, pub(crate) core::marker::PhantomData<MODE>);
         });
     }
 
@@ -224,11 +224,11 @@ fn main() {
             let field_name = format_ident!("{}", region_name.to_lowercase());
             let field_type = format_ident!("{}", get_flash_region_type_name(f.name));
             let field = quote! {
-                pub #field_name: #field_type<'d>
+                pub #field_name: #field_type<'d, MODE>
             };
             let region_name = format_ident!("{}", region_name);
             let init = quote! {
-                #field_name: #field_type(&#region_name, unsafe { p.clone_unchecked()})
+                #field_name: #field_type(&#region_name, unsafe { p.clone_unchecked()}, core::marker::PhantomData)
             };
 
             (field, (init, region_name))
@@ -238,15 +238,17 @@ fn main() {
     let regions_len = flash_memory_regions.len();
     flash_regions.extend(quote! {
         #[cfg(flash)]
-        pub struct FlashLayout<'d> {
+        pub struct FlashLayout<'d, MODE> {
-            #(#fields),*
+            #(#fields),*,
+            _mode: core::marker::PhantomData<MODE>,
         }
 
         #[cfg(flash)]
-        impl<'d> FlashLayout<'d> {
+        impl<'d, MODE> FlashLayout<'d, MODE> {
             pub(crate) fn new(p: embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>) -> Self {
                 Self {
-                    #(#inits),*
+                    #(#inits),*,
+                    _mode: core::marker::PhantomData,
                 }
             }
         }

embassy-stm32/src/flash/asynch.rs

@@ -1,12 +1,21 @@
 use atomic_polyfill::{fence, Ordering};
 use embassy_hal_common::drop::OnDrop;
+use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+use embassy_sync::mutex::Mutex;
 
 use super::{
-    ensure_sector_aligned, family, get_sector, Error, Flash, FLASH_BASE, FLASH_SIZE, MAX_ERASE_SIZE, READ_SIZE,
+    ensure_sector_aligned, family, get_sector, read_blocking, Async, Error, Flash, FlashLayout, FLASH_BASE, FLASH_SIZE,
-    REGION_ACCESS, WRITE_SIZE,
+    MAX_ERASE_SIZE, READ_SIZE, WRITE_SIZE,
 };
 
+pub(super) static REGION_ACCESS: Mutex<CriticalSectionRawMutex, ()> = Mutex::new(());
+
 impl<'d> Flash<'d> {
+    pub fn into_regions(self) -> FlashLayout<'d, Async> {
+        family::set_default_layout();
+        FlashLayout::new(self.inner)
+    }
+
     pub async fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
         unsafe { write_chunked(FLASH_BASE as u32, FLASH_SIZE as u32, offset, bytes).await }
     }
@@ -16,6 +25,18 @@ impl<'d> Flash<'d> {
     }
 }
 
+impl embedded_storage_async::nor_flash::ReadNorFlash for Flash<'_> {
+    const READ_SIZE: usize = READ_SIZE;
+
+    async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
+        self.read(offset, bytes)
+    }
+
+    fn capacity(&self) -> usize {
+        FLASH_SIZE
+    }
+}
+
 impl embedded_storage_async::nor_flash::NorFlash for Flash<'_> {
     const WRITE_SIZE: usize = WRITE_SIZE;
     const ERASE_SIZE: usize = MAX_ERASE_SIZE;
@@ -89,7 +110,11 @@ pub(super) async unsafe fn erase_sectored(base: u32, from: u32, to: u32) -> Resu
 
 foreach_flash_region! {
     ($type_name:ident, $write_size:literal, $erase_size:literal) => {
-        impl crate::_generated::flash_regions::$type_name<'_> {
+        impl crate::_generated::flash_regions::$type_name<'_, Async> {
+            pub fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
+                read_blocking(self.0.base, self.0.size, offset, bytes)
+            }
+
             pub async fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
                 let _guard = REGION_ACCESS.lock().await;
                 unsafe { write_chunked(self.0.base, self.0.size, offset, bytes).await }
@@ -101,7 +126,7 @@ foreach_flash_region! {
             }
         }
 
-        impl embedded_storage_async::nor_flash::ReadNorFlash for crate::_generated::flash_regions::$type_name<'_> {
+        impl embedded_storage_async::nor_flash::ReadNorFlash for crate::_generated::flash_regions::$type_name<'_, Async> {
             const READ_SIZE: usize = READ_SIZE;
 
             async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
@@ -113,7 +138,7 @@ foreach_flash_region! {
             }
         }
 
-        impl embedded_storage_async::nor_flash::NorFlash for crate::_generated::flash_regions::$type_name<'_> {
+        impl embedded_storage_async::nor_flash::NorFlash for crate::_generated::flash_regions::$type_name<'_, Async> {
             const WRITE_SIZE: usize = $write_size;
             const ERASE_SIZE: usize = $erase_size;
 

embassy-stm32/src/flash/common.rs

@@ -1,14 +1,12 @@
 use atomic_polyfill::{fence, Ordering};
 use embassy_cortex_m::interrupt::InterruptExt;
-use embassy_futures::block_on;
 use embassy_hal_common::drop::OnDrop;
 use embassy_hal_common::{into_ref, PeripheralRef};
-use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
-use embassy_sync::mutex::Mutex;
 use stm32_metapac::FLASH_BASE;
 
 use super::{
-    family, Error, FlashBank, FlashLayout, FlashRegion, FlashSector, FLASH_SIZE, MAX_ERASE_SIZE, READ_SIZE, WRITE_SIZE,
+    family, Blocking, Error, FlashBank, FlashLayout, FlashRegion, FlashSector, FLASH_SIZE, MAX_ERASE_SIZE, READ_SIZE,
+    WRITE_SIZE,
 };
 use crate::peripherals::FLASH;
 use crate::Peripheral;
@@ -17,8 +15,6 @@ pub struct Flash<'d> {
     pub(crate) inner: PeripheralRef<'d, FLASH>,
 }
 
-pub(crate) static REGION_ACCESS: Mutex<CriticalSectionRawMutex, ()> = Mutex::new(());
-
 impl<'d> Flash<'d> {
     pub fn new(p: impl Peripheral<P = FLASH> + 'd, irq: impl Peripheral<P = crate::interrupt::FLASH> + 'd) -> Self {
         into_ref!(p, irq);
@@ -30,7 +26,7 @@ impl<'d> Flash<'d> {
         Self { inner: p }
     }
 
-    pub fn into_regions(self) -> FlashLayout<'d> {
+    pub fn into_blocking_regions(self) -> FlashLayout<'d, Blocking> {
         family::set_default_layout();
         FlashLayout::new(self.inner)
     }
@@ -40,11 +36,19 @@ impl<'d> Flash<'d> {
     }
 
     pub fn write_blocking(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
-        unsafe { write_chunked_blocking(FLASH_BASE as u32, FLASH_SIZE as u32, offset, bytes) }
+        unsafe {
+            write_blocking(
+                FLASH_BASE as u32,
+                FLASH_SIZE as u32,
+                offset,
+                bytes,
+                write_chunk_unlocked,
+            )
+        }
     }
 
     pub fn erase_blocking(&mut self, from: u32, to: u32) -> Result<(), Error> {
-        unsafe { erase_sectored_blocking(FLASH_BASE as u32, from, to) }
+        unsafe { erase_blocking(FLASH_BASE as u32, from, to, erase_sector_unlocked) }
     }
 }
 
@@ -59,7 +63,13 @@ pub(super) fn read_blocking(base: u32, size: u32, offset: u32, bytes: &mut [u8])
     Ok(())
 }
 
-pub(super) unsafe fn write_chunked_blocking(base: u32, size: u32, offset: u32, bytes: &[u8]) -> Result<(), Error> {
+pub(super) unsafe fn write_blocking(
+    base: u32,
+    size: u32,
+    offset: u32,
+    bytes: &[u8],
+    write_chunk: unsafe fn(u32, &[u8]) -> Result<(), Error>,
+) -> Result<(), Error> {
     if offset + bytes.len() as u32 > size {
         return Err(Error::Size);
     }
@@ -71,26 +81,39 @@ pub(super) unsafe fn write_chunked_blocking(base: u32, size: u32, offset: u32, b
     trace!("Writing {} bytes at 0x{:x}", bytes.len(), address);
 
     for chunk in bytes.chunks(WRITE_SIZE) {
-        family::clear_all_err();
+        write_chunk(address, chunk)?;
-        fence(Ordering::SeqCst);
-        family::unlock();
-        fence(Ordering::SeqCst);
-        family::enable_blocking_write();
-        fence(Ordering::SeqCst);
-
-        let _on_drop = OnDrop::new(|| {
-            family::disable_blocking_write();
-            fence(Ordering::SeqCst);
-            family::lock();
-        });
-
-        family::write_blocking(address, chunk.try_into().unwrap())?;
         address += WRITE_SIZE as u32;
     }
     Ok(())
 }
 
-pub(super) unsafe fn erase_sectored_blocking(base: u32, from: u32, to: u32) -> Result<(), Error> {
+pub(super) unsafe fn write_chunk_unlocked(address: u32, chunk: &[u8]) -> Result<(), Error> {
+    family::clear_all_err();
+    fence(Ordering::SeqCst);
+    family::unlock();
+    fence(Ordering::SeqCst);
+    family::enable_blocking_write();
+    fence(Ordering::SeqCst);
+
+    let _on_drop = OnDrop::new(|| {
+        family::disable_blocking_write();
+        fence(Ordering::SeqCst);
+        family::lock();
+    });
+
+    family::write_blocking(address, chunk.try_into().unwrap())
+}
+
+pub(super) unsafe fn write_chunk_with_critical_section(address: u32, chunk: &[u8]) -> Result<(), Error> {
+    critical_section::with(|_| write_chunk_unlocked(address, chunk))
+}
+
+pub(super) unsafe fn erase_blocking(
+    base: u32,
+    from: u32,
+    to: u32,
+    erase_sector: unsafe fn(&FlashSector) -> Result<(), Error>,
+) -> Result<(), Error> {
     let start_address = base + from;
     let end_address = base + to;
     let regions = family::get_flash_regions();
@@ -103,21 +126,28 @@ pub(super) unsafe fn erase_sectored_blocking(base: u32, from: u32, to: u32) -> R
     while address < end_address {
         let sector = get_sector(address, regions);
         trace!("Erasing sector: {:?}", sector);
-
+        erase_sector(&sector)?;
-        family::clear_all_err();
-        fence(Ordering::SeqCst);
-        family::unlock();
-        fence(Ordering::SeqCst);
-
-        let _on_drop = OnDrop::new(|| family::lock());
-
-        family::erase_sector_blocking(&sector)?;
         address += sector.size;
     }
     Ok(())
 }
 
-pub(crate) fn get_sector(address: u32, regions: &[&FlashRegion]) -> FlashSector {
+pub(super) unsafe fn erase_sector_unlocked(sector: &FlashSector) -> Result<(), Error> {
+    family::clear_all_err();
+    fence(Ordering::SeqCst);
+    family::unlock();
+    fence(Ordering::SeqCst);
+
+    let _on_drop = OnDrop::new(|| family::lock());
+
+    family::erase_sector_blocking(&sector)
+}
+
+pub(super) unsafe fn erase_sector_with_critical_section(sector: &FlashSector) -> Result<(), Error> {
+    critical_section::with(|_| erase_sector_unlocked(sector))
+}
+
+pub(super) fn get_sector(address: u32, regions: &[&FlashRegion]) -> FlashSector {
     let mut current_bank = FlashBank::Bank1;
     let mut bank_offset = 0;
     for region in regions {
@@ -142,7 +172,7 @@ pub(crate) fn get_sector(address: u32, regions: &[&FlashRegion]) -> FlashSector
     panic!("Flash sector not found");
 }
 
-pub(crate) fn ensure_sector_aligned(
+pub(super) fn ensure_sector_aligned(
     start_address: u32,
     end_address: u32,
     regions: &[&FlashRegion],
@@ -190,121 +220,49 @@ impl embedded_storage::nor_flash::NorFlash for Flash<'_> {
     }
 }
 
-#[cfg(feature = "nightly")]
-impl embedded_storage_async::nor_flash::ReadNorFlash for Flash<'_> {
-    const READ_SIZE: usize = READ_SIZE;
-
-    async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
-        self.read(offset, bytes)
-    }
-
-    fn capacity(&self) -> usize {
-        FLASH_SIZE
-    }
-}
-
-pub struct BlockingFlashRegion<'d, const WRITE_SIZE: u32, const ERASE_SIZE: u32>(
-    &'static FlashRegion,
-    PeripheralRef<'d, FLASH>,
-);
-
-impl<const WRITE_SIZE: u32, const ERASE_SIZE: u32> BlockingFlashRegion<'_, WRITE_SIZE, ERASE_SIZE> {
-    pub fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
-        read_blocking(self.0.base, self.0.size, offset, bytes)
-    }
-
-    pub fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
-        let _guard = block_on(REGION_ACCESS.lock());
-        unsafe { write_chunked_blocking(self.0.base, self.0.size, offset, bytes) }
-    }
-
-    pub fn erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
-        let _guard = block_on(REGION_ACCESS.lock());
-        unsafe { erase_sectored_blocking(self.0.base, from, to) }
-    }
-}
-
-impl<const WRITE_SIZE: u32, const ERASE_SIZE: u32> embedded_storage::nor_flash::ErrorType
-    for BlockingFlashRegion<'_, WRITE_SIZE, ERASE_SIZE>
-{
-    type Error = Error;
-}
-
-impl<const WRITE_SIZE: u32, const ERASE_SIZE: u32> embedded_storage::nor_flash::ReadNorFlash
-    for BlockingFlashRegion<'_, WRITE_SIZE, ERASE_SIZE>
-{
-    const READ_SIZE: usize = READ_SIZE;
-
-    fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
-        self.read(offset, bytes)
-    }
-
-    fn capacity(&self) -> usize {
-        self.0.size as usize
-    }
-}
-
-impl<const WRITE_SIZE: u32, const ERASE_SIZE: u32> embedded_storage::nor_flash::NorFlash
-    for BlockingFlashRegion<'_, WRITE_SIZE, ERASE_SIZE>
-{
-    const WRITE_SIZE: usize = WRITE_SIZE as usize;
-    const ERASE_SIZE: usize = ERASE_SIZE as usize;
-
-    fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
-        self.write(offset, bytes)
-    }
-
-    fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
-        self.erase(from, to)
-    }
-}
-
 foreach_flash_region! {
     ($type_name:ident, $write_size:literal, $erase_size:literal) => {
-        paste::paste! {
+        impl<'d> crate::_generated::flash_regions::$type_name<'d, Blocking> {
-            pub type [<Blocking $type_name>]<'d> = BlockingFlashRegion<'d, $write_size, $erase_size>;
+            pub fn read_blocking(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
-        }
-
-        impl<'d> crate::_generated::flash_regions::$type_name<'d> {
-            /// Make this flash region work in a blocking context.
-            ///
-            /// SAFETY
-            ///
-            /// This function is unsafe as incorect usage of parallel blocking operations
-            /// on multiple regions may cause a deadlock because each region requires mutual access to the flash.
-            pub unsafe fn into_blocking(self) -> BlockingFlashRegion<'d, $write_size, $erase_size> {
-                BlockingFlashRegion(self.0, self.1)
-            }
-
-            pub fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
                 read_blocking(self.0.base, self.0.size, offset, bytes)
             }
 
-            pub fn try_write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
+            pub fn write_blocking(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
-                let _guard = REGION_ACCESS.try_lock().map_err(|_| Error::TryLockError)?;
+                unsafe { write_blocking(self.0.base, self.0.size, offset, bytes, write_chunk_with_critical_section) }
-                unsafe { write_chunked_blocking(self.0.base, self.0.size, offset, bytes) }
             }
 
-            pub fn try_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
+            pub fn erase_blocking(&mut self, from: u32, to: u32) -> Result<(), Error> {
-                let _guard = REGION_ACCESS.try_lock().map_err(|_| Error::TryLockError)?;
+                unsafe { erase_blocking(self.0.base, from, to, erase_sector_with_critical_section) }
-                unsafe { erase_sectored_blocking(self.0.base, from, to) }
             }
         }
 
-        impl embedded_storage::nor_flash::ErrorType for crate::_generated::flash_regions::$type_name<'_> {
+        impl<MODE> embedded_storage::nor_flash::ErrorType for crate::_generated::flash_regions::$type_name<'_, MODE> {
             type Error = Error;
         }
 
-        impl embedded_storage::nor_flash::ReadNorFlash for crate::_generated::flash_regions::$type_name<'_> {
+        impl embedded_storage::nor_flash::ReadNorFlash for crate::_generated::flash_regions::$type_name<'_, Blocking> {
             const READ_SIZE: usize = READ_SIZE;
 
             fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
-                self.read(offset, bytes)
+                self.read_blocking(offset, bytes)
             }
 
             fn capacity(&self) -> usize {
                 self.0.size as usize
             }
         }
+
+        impl embedded_storage::nor_flash::NorFlash for crate::_generated::flash_regions::$type_name<'_, Blocking> {
+            const WRITE_SIZE: usize = $write_size;
+            const ERASE_SIZE: usize = $erase_size;
+
+            fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
+                self.write_blocking(offset, bytes)
+            }
+
+            fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
+                self.erase_blocking(from, to)
+            }
+        }
     };
 }

embassy-stm32/src/flash/f4.rs

@@ -11,6 +11,8 @@ use crate::pac;
 
 #[cfg(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f469, stm32f479))]
 mod alt_regions {
+    use core::marker::PhantomData;
+
     use embassy_hal_common::PeripheralRef;
     use stm32_metapac::FLASH_SIZE;
 
@@ -18,8 +20,7 @@ mod alt_regions {
     #[cfg(feature = "nightly")]
     use crate::flash::asynch;
     use crate::flash::{
-        common, Bank1Region1, Bank1Region2, BlockingFlashRegion, Error, Flash, FlashBank, FlashRegion, READ_SIZE,
+        common, Async, Bank1Region1, Bank1Region2, Blocking, Error, Flash, FlashBank, FlashRegion, READ_SIZE,
-        REGION_ACCESS,
     };
     use crate::peripherals::FLASH;
 
@@ -53,101 +54,86 @@ mod alt_regions {
         &ALT_BANK2_REGION3,
     ];
 
-    pub struct AltBank1Region3<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank1Region3<'d, MODE>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>, PhantomData<MODE>);
-    pub struct AltBank2Region1<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank2Region1<'d, MODE>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>, PhantomData<MODE>);
-    pub struct AltBank2Region2<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank2Region2<'d, MODE>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>, PhantomData<MODE>);
-    pub struct AltBank2Region3<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank2Region3<'d, MODE>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>, PhantomData<MODE>);
 
-    pub type BlockingAltBank1Region3<'d> =
+    pub struct AltFlashLayout<'d, MODE> {
-        BlockingFlashRegion<'d, { ALT_BANK1_REGION3.write_size }, { ALT_BANK1_REGION3.erase_size }>;
+        pub bank1_region1: Bank1Region1<'d, MODE>,
-    pub type BlockingAltBank2Region1<'d> =
+        pub bank1_region2: Bank1Region2<'d, MODE>,
-        BlockingFlashRegion<'d, { ALT_BANK2_REGION1.write_size }, { ALT_BANK2_REGION1.erase_size }>;
+        pub bank1_region3: AltBank1Region3<'d, MODE>,
-    pub type BlockingAltBank2Region2<'d> =
+        pub bank2_region1: AltBank2Region1<'d, MODE>,
-        BlockingFlashRegion<'d, { ALT_BANK2_REGION2.write_size }, { ALT_BANK2_REGION2.erase_size }>;
+        pub bank2_region2: AltBank2Region2<'d, MODE>,
-    pub type BlockingAltBank2Region3<'d> =
+        pub bank2_region3: AltBank2Region3<'d, MODE>,
-        BlockingFlashRegion<'d, { ALT_BANK2_REGION3.write_size }, { ALT_BANK2_REGION3.erase_size }>;
+        pub otp_region: OTPRegion<'d, MODE>,
-
-    pub struct AltFlashLayout<'d> {
-        pub bank1_region1: Bank1Region1<'d>,
-        pub bank1_region2: Bank1Region2<'d>,
-        pub bank1_region3: AltBank1Region3<'d>,
-        pub bank2_region1: AltBank2Region1<'d>,
-        pub bank2_region2: AltBank2Region2<'d>,
-        pub bank2_region3: AltBank2Region3<'d>,
-        pub otp_region: OTPRegion<'d>,
     }
 
     impl<'d> Flash<'d> {
-        pub fn into_alt_regions(self) -> AltFlashLayout<'d> {
+        pub fn into_alt_regions(self) -> AltFlashLayout<'d, Async> {
+            unsafe { crate::pac::FLASH.optcr().modify(|r| r.set_db1m(true)) };
+
+            // SAFETY: We never expose the cloned peripheral references, and their instance is not public.
+            // Also, all async flash region operations are protected with a mutex.
+            let p = self.inner;
+            AltFlashLayout {
+                bank1_region1: Bank1Region1(&BANK1_REGION1, unsafe { p.clone_unchecked() }, PhantomData),
+                bank1_region2: Bank1Region2(&BANK1_REGION2, unsafe { p.clone_unchecked() }, PhantomData),
+                bank1_region3: AltBank1Region3(&ALT_BANK1_REGION3, unsafe { p.clone_unchecked() }, PhantomData),
+                bank2_region1: AltBank2Region1(&ALT_BANK2_REGION1, unsafe { p.clone_unchecked() }, PhantomData),
+                bank2_region2: AltBank2Region2(&ALT_BANK2_REGION2, unsafe { p.clone_unchecked() }, PhantomData),
+                bank2_region3: AltBank2Region3(&ALT_BANK2_REGION3, unsafe { p.clone_unchecked() }, PhantomData),
+                otp_region: OTPRegion(&OTP_REGION, unsafe { p.clone_unchecked() }, PhantomData),
+            }
+        }
+
+        pub fn into_alt_blocking_regions(self) -> AltFlashLayout<'d, Blocking> {
             unsafe { crate::pac::FLASH.optcr().modify(|r| r.set_db1m(true)) };
 
             // SAFETY: We never expose the cloned peripheral references, and their instance is not public.
             // Also, all blocking flash region operations are protected with a cs.
             let p = self.inner;
             AltFlashLayout {
-                bank1_region1: Bank1Region1(&BANK1_REGION1, unsafe { p.clone_unchecked() }),
+                bank1_region1: Bank1Region1(&BANK1_REGION1, unsafe { p.clone_unchecked() }, PhantomData),
-                bank1_region2: Bank1Region2(&BANK1_REGION2, unsafe { p.clone_unchecked() }),
+                bank1_region2: Bank1Region2(&BANK1_REGION2, unsafe { p.clone_unchecked() }, PhantomData),
-                bank1_region3: AltBank1Region3(&ALT_BANK1_REGION3, unsafe { p.clone_unchecked() }),
+                bank1_region3: AltBank1Region3(&ALT_BANK1_REGION3, unsafe { p.clone_unchecked() }, PhantomData),
-                bank2_region1: AltBank2Region1(&ALT_BANK2_REGION1, unsafe { p.clone_unchecked() }),
+                bank2_region1: AltBank2Region1(&ALT_BANK2_REGION1, unsafe { p.clone_unchecked() }, PhantomData),
-                bank2_region2: AltBank2Region2(&ALT_BANK2_REGION2, unsafe { p.clone_unchecked() }),
+                bank2_region2: AltBank2Region2(&ALT_BANK2_REGION2, unsafe { p.clone_unchecked() }, PhantomData),
-                bank2_region3: AltBank2Region3(&ALT_BANK2_REGION3, unsafe { p.clone_unchecked() }),
+                bank2_region3: AltBank2Region3(&ALT_BANK2_REGION3, unsafe { p.clone_unchecked() }, PhantomData),
-                otp_region: OTPRegion(&OTP_REGION, unsafe { p.clone_unchecked() }),
+                otp_region: OTPRegion(&OTP_REGION, unsafe { p.clone_unchecked() }, PhantomData),
             }
         }
     }
 
     macro_rules! foreach_altflash_region {
         ($type_name:ident, $region:ident) => {
-            impl $type_name<'_> {
+            #[cfg(feature = "nightly")]
-                pub fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
+            impl $type_name<'_, Async> {
+                pub async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
                     common::read_blocking(self.0.base, self.0.size, offset, bytes)
                 }
 
-                #[cfg(feature = "nightly")]
                 pub async fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
-                    let _guard = REGION_ACCESS.lock().await;
+                    let _guard = asynch::REGION_ACCESS.lock().await;
                     unsafe { asynch::write_chunked(self.0.base, self.0.size, offset, bytes).await }
                 }
 
-                #[cfg(feature = "nightly")]
                 pub async fn erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
-                    let _guard = REGION_ACCESS.lock().await;
+                    let _guard = asynch::REGION_ACCESS.lock().await;
                     unsafe { asynch::erase_sectored(self.0.base, from, to).await }
                 }
-
-                pub fn try_write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
-                    let _guard = REGION_ACCESS.try_lock().map_err(|_| Error::TryLockError)?;
-                    unsafe { common::write_chunked_blocking(self.0.base, self.0.size, offset, bytes) }
-                }
-
-                pub fn try_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
-                    let _guard = REGION_ACCESS.try_lock().map_err(|_| Error::TryLockError)?;
-                    unsafe { common::erase_sectored_blocking(self.0.base, from, to) }
-                }
             }
 
-            impl embedded_storage::nor_flash::ErrorType for $type_name<'_> {
+            impl embedded_storage::nor_flash::ErrorType for $type_name<'_, Async> {
                 type Error = Error;
             }
 
-            impl embedded_storage::nor_flash::ReadNorFlash for $type_name<'_> {
-                const READ_SIZE: usize = READ_SIZE;
-
-                fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
-                    self.read(offset, bytes)
-                }
-
-                fn capacity(&self) -> usize {
-                    self.0.size as usize
-                }
-            }
-
             #[cfg(feature = "nightly")]
-            impl embedded_storage_async::nor_flash::ReadNorFlash for $type_name<'_> {
+            impl embedded_storage_async::nor_flash::ReadNorFlash for $type_name<'_, Async> {
                 const READ_SIZE: usize = READ_SIZE;
 
                 async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
-                    self.read(offset, bytes)
+                    self.read(offset, bytes).await
                 }
 
                 fn capacity(&self) -> usize {
@@ -156,7 +142,7 @@ mod alt_regions {
             }
 
             #[cfg(feature = "nightly")]
-            impl embedded_storage_async::nor_flash::NorFlash for $type_name<'_> {
+            impl embedded_storage_async::nor_flash::NorFlash for $type_name<'_, Async> {
                 const WRITE_SIZE: usize = $region.write_size as usize;
                 const ERASE_SIZE: usize = $region.erase_size as usize;
 

embassy-stm32/src/flash/mod.rs

@@ -14,6 +14,9 @@ pub use crate::pac::{FLASH_BASE, FLASH_SIZE, WRITE_SIZE};
 
 pub const READ_SIZE: usize = 1;
 
+pub struct Blocking;
+pub struct Async;
+
 #[derive(Debug)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct FlashRegion {