Add nrf softdevice feature

Cargo.toml

@@ -29,5 +29,19 @@ default-features = false
 version = "0.8.11"
 features = ["const_mut_refs"]
 
+[dependencies.critical-section]
+version = "0.2.7"
+optional = true
+
+[dependencies.embassy]
+version = "0.1.0"
+optional = true
+
+[features]
+nrf-softdevice = ["dep:critical-section", "dep:embassy"]
+
 [dev-dependencies]
 cortex-m-rt = "0.6.12"
+
+# [patch.crates-io]
+# embassy = { git = "https://github.com/embassy-rs/embassy" }

README.md

@@ -9,6 +9,11 @@ This project is developed and maintained by the [Cortex-M team][team].
 
 ## [Documentation](https://docs.rs/alloc-cortex-m)
 
+## Features
+
+The `nrf-softdevice` feature replaces `cortex_m::interrupt::free()` with
+`critical_section::with()` when block interrupts.
+
 ## [Change log](CHANGELOG.md)
 
 ## License

src/lib.rs

@@ -12,9 +12,34 @@ use core::alloc::{GlobalAlloc, Layout};
 use core::cell::RefCell;
 use core::ptr::{self, NonNull};
 
-use cortex_m::interrupt::Mutex;
+#[cfg(not(feature = "nrf-softdevice"))]
+use cortex_m::interrupt::{
+    Mutex,
+    CriticalSection,
+};
+#[cfg(feature = "nrf-softdevice")]
+use {
+    critical_section::CriticalSection,
+    embassy::blocking_mutex::CriticalSectionMutex as Mutex,
+};
 use linked_list_allocator::Heap;
 
+#[cfg(not(feature = "nrf-softdevice"))]
+#[inline]
+fn block_interrupts<F, R>(f: F) -> R
+    where F: FnOnce(&CriticalSection) -> R
+{
+    cortex_m::interrupt::free(f)
+}
+
+#[cfg(feature = "nrf-softdevice")]
+#[inline]
+fn block_interrupts<F, R>(f: F) -> R
+    where F: FnOnce(CriticalSection) -> R
+{
+    critical_section::with(f)
+}
+
 pub struct CortexMHeap {
     heap: Mutex<RefCell<Heap>>,
 }
@@ -24,12 +49,20 @@ impl CortexMHeap {
     ///
     /// You must initialize this heap using the
     /// [`init`](struct.CortexMHeap.html#method.init) method before using the allocator.
+    #[cfg(not(feature = "nrf-softdevice"))]
     pub const fn empty() -> CortexMHeap {
         CortexMHeap {
             heap: Mutex::new(RefCell::new(Heap::empty())),
         }
     }
 
+    #[cfg(feature = "nrf-softdevice")]
+    pub fn empty() -> CortexMHeap {
+        CortexMHeap {
+            heap: Mutex::new(RefCell::new(Heap::empty())),
+        }
+    }
+
     /// Initializes the heap
     ///
     /// This function must be called BEFORE you run any code that makes use of the
@@ -54,25 +87,25 @@ impl CortexMHeap {
     /// - This function must be called exactly ONCE.
     /// - `size > 0`
     pub unsafe fn init(&self, start_addr: usize, size: usize) {
-        cortex_m::interrupt::free(|cs| {
+        block_interrupts(|cs| {
             self.heap.borrow(cs).borrow_mut().init(start_addr, size);
         });
     }
 
     /// Returns an estimate of the amount of bytes in use.
     pub fn used(&self) -> usize {
-        cortex_m::interrupt::free(|cs| self.heap.borrow(cs).borrow_mut().used())
+        block_interrupts(|cs| self.heap.borrow(cs).borrow_mut().used())
     }
 
     /// Returns an estimate of the amount of bytes available.
     pub fn free(&self) -> usize {
-        cortex_m::interrupt::free(|cs| self.heap.borrow(cs).borrow_mut().free())
+        block_interrupts(|cs| self.heap.borrow(cs).borrow_mut().free())
     }
 }
 
 unsafe impl GlobalAlloc for CortexMHeap {
     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        cortex_m::interrupt::free(|cs| {
+        block_interrupts(|cs| {
             self.heap
                 .borrow(cs)
                 .borrow_mut()
@@ -83,7 +116,7 @@ unsafe impl GlobalAlloc for CortexMHeap {
     }
 
     unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
-        cortex_m::interrupt::free(|cs| {
+        block_interrupts(|cs| {
             self.heap
                 .borrow(cs)
                 .borrow_mut()