Remove unnecessary use of atomic-polyfill.

Only use it when CAS is actually needed.

.vscode/settings.json

@@ -4,7 +4,8 @@
   "rust-analyzer.checkOnSave.noDefaultFeatures": true,
   "rust-analyzer.cargo.noDefaultFeatures": true,
   "rust-analyzer.procMacro.enable": true,
-  "rust-analyzer.cargo.target": "thumbv7em-none-eabi",
+  //"rust-analyzer.cargo.target": "thumbv7em-none-eabi",
+  "rust-analyzer.cargo.target": "thumbv8m.main-none-eabihf",
   "rust-analyzer.cargo.features": [
     // These are needed to prevent embassy-net from failing to build
     //"embassy-net/medium-ethernet",
@@ -12,14 +13,14 @@
     //"embassy-net/pool-16",
     //"time-tick-16mhz",
     //"defmt-timestamp-uptime",
-    "nightly",
+    //"nightly",
     //"unstable-traits",
   ],
   "rust-analyzer.linkedProjects": [
     // Declare for the target you wish to develop
     //"embassy-executor/Cargo.toml",
     //"embassy-sync/Cargo.toml",
-    "examples/nrf/Cargo.toml",
+    //"examples/nrf/Cargo.toml",
     // "examples/nrf-rtos-trace/Cargo.toml",
     // "examples/rp/Cargo.toml",
     // "examples/std/Cargo.toml",
@@ -35,7 +36,7 @@
     // "examples/stm32l0/Cargo.toml",
     // "examples/stm32l1/Cargo.toml",
     // "examples/stm32l4/Cargo.toml",
-    // "examples/stm32l5/Cargo.toml",
+    "examples/stm32l5/Cargo.toml",
     // "examples/stm32u5/Cargo.toml",
     // "examples/stm32wb/Cargo.toml",
     // "examples/stm32wb55/Cargo.toml",

embassy-executor/src/arch/riscv32.rs

@@ -1,7 +1,6 @@
 use core::marker::PhantomData;
 use core::ptr;
-
-use atomic_polyfill::{AtomicBool, Ordering};
+use core::sync::atomic::{AtomicBool, Ordering};
 
 use super::{raw, Spawner};
 

embassy-executor/src/arch/xtensa.rs

@@ -1,7 +1,6 @@
 use core::marker::PhantomData;
 use core::ptr;
-
-use atomic_polyfill::{AtomicBool, Ordering};
+use core::sync::atomic::{AtomicBool, Ordering};
 
 use super::{raw, Spawner};
 

embassy-net/Cargo.toml

@@ -51,7 +51,6 @@ generic-array = { version = "0.14.4", default-features = false }
 stable_deref_trait = { version = "1.2.0", default-features = false }
 futures = { version = "0.3.17", default-features = false, features = [ "async-await" ] }
 atomic-pool = "1.0"
-atomic-polyfill = "1.0.1"
 embedded-nal-async = { version = "0.3.0", optional = true }
 
 [dependencies.smoltcp]

embassy-net/src/tcp.rs

@@ -329,8 +329,8 @@ pub mod client {
     use core::cell::UnsafeCell;
     use core::mem::MaybeUninit;
     use core::ptr::NonNull;
+    use core::sync::atomic::{AtomicBool, Ordering};
 
-    use atomic_polyfill::{AtomicBool, Ordering};
     use embedded_nal_async::IpAddr;
 
     use super::*;

embassy-rp/src/multicore.rs

@@ -29,9 +29,7 @@
 //! ```
 
 use core::mem::ManuallyDrop;
-use core::sync::atomic::{compiler_fence, Ordering};
-
-use atomic_polyfill::AtomicBool;
+use core::sync::atomic::{compiler_fence, AtomicBool, Ordering};
 
 use crate::interrupt::{Interrupt, InterruptExt};
 use crate::peripherals::CORE1;

embassy-rp/src/usb.rs

@@ -1,10 +1,9 @@
 use core::future::poll_fn;
 use core::marker::PhantomData;
 use core::slice;
-use core::sync::atomic::Ordering;
+use core::sync::atomic::{compiler_fence, Ordering};
 use core::task::Poll;
 
-use atomic_polyfill::compiler_fence;
 use embassy_hal_common::into_ref;
 use embassy_sync::waitqueue::AtomicWaker;
 use embassy_usb_driver as driver;

embassy-stm32/src/adc/v4.rs

@@ -1,4 +1,5 @@
-use atomic_polyfill::{AtomicU8, Ordering};
+use core::sync::atomic::{AtomicU8, Ordering};
+
 use embedded_hal_02::blocking::delay::DelayUs;
 use pac::adc::vals::{Adcaldif, Boost, Difsel, Exten, Pcsel};
 use pac::adccommon::vals::Presc;

embassy-stm32/src/flash/f4.rs

@@ -1,7 +1,6 @@
 use core::convert::TryInto;
 use core::ptr::write_volatile;
-
-use atomic_polyfill::{fence, Ordering};
+use core::sync::atomic::{fence, Ordering};
 
 use super::{ERASE_SIZE, FLASH_BASE, FLASH_SIZE};
 use crate::flash::Error;

embassy-stm32/src/flash/f7.rs

@@ -1,7 +1,6 @@
 use core::convert::TryInto;
 use core::ptr::write_volatile;
-
-use atomic_polyfill::{fence, Ordering};
+use core::sync::atomic::{fence, Ordering};
 
 use crate::flash::Error;
 use crate::pac;

embassy-stm32/src/flash/h7.rs

@@ -41,7 +41,7 @@ pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error
 
     cortex_m::asm::isb();
     cortex_m::asm::dsb();
-    atomic_polyfill::fence(atomic_polyfill::Ordering::SeqCst);
+    core::sync::atomic::fence(core::sync::atomic::Ordering::SeqCst);
 
     let ret = {
         let mut ret: Result<(), Error> = Ok(());
@@ -70,7 +70,7 @@ pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error
 
     cortex_m::asm::isb();
     cortex_m::asm::dsb();
-    atomic_polyfill::fence(atomic_polyfill::Ordering::SeqCst);
+    core::sync::atomic::fence(core::sync::atomic::Ordering::SeqCst);
 
     ret
 }

embassy-stm32/src/i2c/v2.rs

@@ -1,8 +1,8 @@
 use core::cmp;
 use core::future::poll_fn;
+use core::sync::atomic::{AtomicUsize, Ordering};
 use core::task::Poll;
 
-use atomic_polyfill::{AtomicUsize, Ordering};
 use embassy_embedded_hal::SetConfig;
 use embassy_hal_common::drop::OnDrop;
 use embassy_hal_common::{into_ref, PeripheralRef};
@@ -131,7 +131,8 @@ impl<'d, T: Instance, TXDMA, RXDMA> I2c<'d, T, TXDMA, RXDMA> {
 
         if isr.tcr() || isr.tc() {
             let state = T::state();
-            state.chunks_transferred.fetch_add(1, Ordering::Relaxed);
+            let transferred = state.chunks_transferred.load(Ordering::Relaxed);
+            state.chunks_transferred.store(transferred + 1, Ordering::Relaxed);
             state.waker.wake();
         }
         // The flag can only be cleared by writting to nbytes, we won't do that here, so disable

embassy-stm32/src/usart/buffered.rs

@@ -1,8 +1,8 @@
 use core::cell::RefCell;
 use core::future::poll_fn;
+use core::sync::atomic::{compiler_fence, Ordering};
 use core::task::Poll;
 
-use atomic_polyfill::{compiler_fence, Ordering};
 use embassy_cortex_m::peripheral::{PeripheralMutex, PeripheralState, StateStorage};
 use embassy_hal_common::ring_buffer::RingBuffer;
 use embassy_sync::waitqueue::WakerRegistration;

embassy-stm32/src/usart/mod.rs

@@ -2,9 +2,9 @@
 
 use core::future::poll_fn;
 use core::marker::PhantomData;
+use core::sync::atomic::{compiler_fence, Ordering};
 use core::task::Poll;
 
-use atomic_polyfill::{compiler_fence, Ordering};
 use embassy_cortex_m::interrupt::InterruptExt;
 use embassy_futures::select::{select, Either};
 use embassy_hal_common::drop::OnDrop;

embassy-sync/Cargo.toml

@@ -31,7 +31,6 @@ defmt = { version = "0.3", optional = true }
 log = { version = "0.4.14", optional = true }
 
 futures-util = { version = "0.3.17", default-features = false }
-atomic-polyfill = "1.0.1"
 critical-section = "1.1"
 heapless = "0.7.5"
 cfg-if = "1.0.0"