Migrate to portable-atomic

Author: ithinuel

.github/workflows/doctests.yml

@@ -9,23 +9,13 @@ name: Documentation Tests
 jobs:
   build:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        include:
-          - rust: stable
-            features: thumbv6
-            nodefault: "--no-default-features"
-          - rust: stable
-            features: ""
-            nodefault: ""
-
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: ${{ matrix.rust }}
+          toolchain: stable
       - uses: actions-rs/cargo@v1
         with:
           command: test
-          args: ${{ matrix.nodefault }} --features=${{ matrix.features }} --manifest-path core/Cargo.toml
+          args: --manifest-path core/Cargo.toml

.github/workflows/embedded-builds.yml

@@ -15,7 +15,7 @@ jobs:
           - features: ""
             target: thumbv7em-none-eabihf
             rust: stable
-          - feature: thumbv6
+          - feature: portable-atomic/critical-section
             target: thumbv6m-none-eabi
             rust: stable
 

core/Cargo.toml

@@ -15,11 +15,8 @@ categories = [
 license = "MIT OR Apache-2.0"
 
 [dependencies]
-cortex-m = { version = "0.6.0", optional = true }
-
-[dependencies.defmt]
-version = "0.3.0"
-optional = true
+portable-atomic = { version = "1.5.1", default-features = false, features = ["require-cas"] }
+defmt = { version = "0.3.0", optional = true }
 
 [package.metadata.docs.rs]
 all-features = true

core/src/bbbuffer.rs

@@ -11,11 +11,10 @@ use core::{
     ptr::NonNull,
     result::Result as CoreResult,
     slice::from_raw_parts_mut,
-    sync::atomic::{
-        AtomicBool, AtomicUsize,
-        Ordering::{AcqRel, Acquire, Release},
-    },
+    sync::atomic::Ordering::{AcqRel, Acquire, Release},
 };
+use portable_atomic::{AtomicBool, AtomicUsize};
+
 #[derive(Debug)]
 /// A backing structure for a BBQueue. Can be used to create either
 /// a BBQueue or a split Producer/Consumer pair
@@ -86,7 +85,7 @@ impl<'a, const N: usize> BBBuffer<N> {
     /// # }
     /// ```
     pub fn try_split(&'a self) -> Result<(Producer<'a, N>, Consumer<'a, N>)> {
-        if atomic::swap(&self.already_split, true, AcqRel) {
+        if self.already_split.swap(true, AcqRel) {
             return Err(Error::AlreadySplit);
         }
 
@@ -352,7 +351,7 @@ impl<'a, const N: usize> Producer<'a, N> {
     pub fn grant_exact(&mut self, sz: usize) -> Result<GrantW<'a, N>> {
         let inner = unsafe { &self.bbq.as_ref() };
 
-        if atomic::swap(&inner.write_in_progress, true, AcqRel) {
+        if inner.write_in_progress.swap(true, AcqRel) {
             return Err(Error::GrantInProgress);
         }
 
@@ -450,7 +449,7 @@ impl<'a, const N: usize> Producer<'a, N> {
     pub fn grant_max_remaining(&mut self, mut sz: usize) -> Result<GrantW<'a, N>> {
         let inner = unsafe { &self.bbq.as_ref() };
 
-        if atomic::swap(&inner.write_in_progress, true, AcqRel) {
+        if inner.write_in_progress.swap(true, AcqRel) {
             return Err(Error::GrantInProgress);
         }
 
@@ -555,7 +554,7 @@ impl<'a, const N: usize> Consumer<'a, N> {
     pub fn read(&mut self) -> Result<GrantR<'a, N>> {
         let inner = unsafe { &self.bbq.as_ref() };
 
-        if atomic::swap(&inner.read_in_progress, true, AcqRel) {
+        if inner.read_in_progress.swap(true, AcqRel) {
             return Err(Error::GrantInProgress);
         }
 
@@ -607,7 +606,7 @@ impl<'a, const N: usize> Consumer<'a, N> {
     pub fn split_read(&mut self) -> Result<SplitGrantR<'a, N>> {
         let inner = unsafe { &self.bbq.as_ref() };
 
-        if atomic::swap(&inner.read_in_progress, true, AcqRel) {
+        if inner.read_in_progress.swap(true, AcqRel) {
             return Err(Error::GrantInProgress);
         }
 
@@ -814,7 +813,7 @@ impl<'a, const N: usize> GrantW<'a, N> {
         let used = min(len, used);
 
         let write = inner.write.load(Acquire);
-        atomic::fetch_sub(&inner.reserve, len - used, AcqRel);
+        inner.reserve.fetch_sub(len - used, AcqRel);
 
         let max = N;
         let last = inner.last.load(Acquire);
@@ -951,7 +950,7 @@ impl<'a, const N: usize> GrantR<'a, N> {
         debug_assert!(used <= self.buf.len());
 
         // This should be fine, purely incrementing
-        let _ = atomic::fetch_add(&inner.read, used, Release);
+        let _ = inner.read.fetch_add(used, Release);
 
         inner.read_in_progress.store(false, Release);
     }
@@ -1036,7 +1035,7 @@ impl<'a, const N: usize> SplitGrantR<'a, N> {
 
         if used <= self.buf1.len() {
             // This should be fine, purely incrementing
-            let _ = atomic::fetch_add(&inner.read, used, Release);
+            let _ = inner.read.fetch_add(used, Release);
         } else {
             // Also release parts of the second buffer
             inner.read.store(used - self.buf1.len(), Release);
@@ -1101,59 +1100,3 @@ impl<'a, const N: usize> DerefMut for GrantR<'a, N> {
         self.buf
     }
 }
-
-#[cfg(feature = "thumbv6")]
-mod atomic {
-    use core::sync::atomic::{
-        AtomicBool, AtomicUsize,
-        Ordering::{self, Acquire, Release},
-    };
-    use cortex_m::interrupt::free;
-
-    #[inline(always)]
-    pub fn fetch_add(atomic: &AtomicUsize, val: usize, _order: Ordering) -> usize {
-        free(|_| {
-            let prev = atomic.load(Acquire);
-            atomic.store(prev.wrapping_add(val), Release);
-            prev
-        })
-    }
-
-    #[inline(always)]
-    pub fn fetch_sub(atomic: &AtomicUsize, val: usize, _order: Ordering) -> usize {
-        free(|_| {
-            let prev = atomic.load(Acquire);
-            atomic.store(prev.wrapping_sub(val), Release);
-            prev
-        })
-    }
-
-    #[inline(always)]
-    pub fn swap(atomic: &AtomicBool, val: bool, _order: Ordering) -> bool {
-        free(|_| {
-            let prev = atomic.load(Acquire);
-            atomic.store(val, Release);
-            prev
-        })
-    }
-}
-
-#[cfg(not(feature = "thumbv6"))]
-mod atomic {
-    use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
-
-    #[inline(always)]
-    pub fn fetch_add(atomic: &AtomicUsize, val: usize, order: Ordering) -> usize {
-        atomic.fetch_add(val, order)
-    }
-
-    #[inline(always)]
-    pub fn fetch_sub(atomic: &AtomicUsize, val: usize, order: Ordering) -> usize {
-        atomic.fetch_sub(val, order)
-    }
-
-    #[inline(always)]
-    pub fn swap(atomic: &AtomicBool, val: bool, order: Ordering) -> bool {
-        atomic.swap(val, order)
-    }
-}