2 files changed, 33 insertions, 8 deletions

diff --git a/embassy-rp/src/uart/buffered.rs b/embassy-rp/src/uart/buffered.rs
index 02649ad81..fdb8ce776 100644
--- a/embassy-rp/src/uart/buffered.rs
+++ b/embassy-rp/src/uart/buffered.rs
@@ -1,8 +1,8 @@
 //! Buffered UART driver.
 use core::future::Future;
 use core::slice;
+use core::sync::atomic::{AtomicU8, Ordering};
 
-use atomic_polyfill::AtomicU8;
 use embassy_hal_internal::atomic_ring_buffer::RingBuffer;
 
 use super::*;
@@ -241,7 +241,11 @@ impl BufferedUartRx {
     }
 
     fn get_rx_error(state: &State) -> Option<Error> {
-        let errs = state.rx_error.swap(0, Ordering::Relaxed);
+        let errs = critical_section::with(|_| {
+            let val = state.rx_error.load(Ordering::Relaxed);
+            state.rx_error.store(0, Ordering::Relaxed);
+            val
+        });
         if errs & RXE_OVERRUN != 0 {
             Some(Error::Overrun)
         } else if errs & RXE_BREAK != 0 {
@@ -555,7 +559,10 @@ impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for BufferedInterr
                 }
                 let dr = r.uartdr().read();
                 if (dr.0 >> 8) != 0 {
-                    s.rx_error.fetch_or((dr.0 >> 8) as u8, Ordering::Relaxed);
+                    critical_section::with(|_| {
+                        let val = s.rx_error.load(Ordering::Relaxed);
+                        s.rx_error.store(val | ((dr.0 >> 8) as u8), Ordering::Relaxed);
+                    });
                     error = true;
                     // only fill the buffer with valid characters. the current character is fine
                     // if the error is an overrun, but if we add it to the buffer we'll report
diff --git a/embassy-rp/src/uart/mod.rs b/embassy-rp/src/uart/mod.rs
index 8be87a5d2..b7b569dd5 100644
--- a/embassy-rp/src/uart/mod.rs
+++ b/embassy-rp/src/uart/mod.rs
@@ -1,9 +1,9 @@
 //! UART driver.
 use core::future::poll_fn;
 use core::marker::PhantomData;
+use core::sync::atomic::{AtomicU16, Ordering};
 use core::task::Poll;
 
-use atomic_polyfill::{AtomicU16, Ordering};
 use embassy_futures::select::{Either, select};
 use embassy_hal_internal::{Peri, PeripheralType};
 use embassy_sync::waitqueue::AtomicWaker;
@@ -456,7 +456,12 @@ impl<'d> UartRx<'d, Async> {
             transfer,
             poll_fn(|cx| {
                 self.dma_state.rx_err_waker.register(cx.waker());
-                match self.dma_state.rx_errs.swap(0, Ordering::Relaxed) {
+                let rx_errs = critical_section::with(|_| {
+                    let val = self.dma_state.rx_errs.load(Ordering::Relaxed);
+                    self.dma_state.rx_errs.store(0, Ordering::Relaxed);
+                    val
+                });
+                match rx_errs {
                     0 => Poll::Pending,
                     e => Poll::Ready(Uartris(e as u32)),
                 }
@@ -468,7 +473,11 @@ impl<'d> UartRx<'d, Async> {
             Either::First(()) => {
                 // We're here because the DMA finished, BUT if an error occurred on the LAST
                 // byte, then we may still need to grab the error state!
-                Uartris(self.dma_state.rx_errs.swap(0, Ordering::Relaxed) as u32)
+                Uartris(critical_section::with(|_| {
+                    let val = self.dma_state.rx_errs.load(Ordering::Relaxed);
+                    self.dma_state.rx_errs.store(0, Ordering::Relaxed);
+                    val
+                }) as u32)
             }
             Either::Second(e) => {
                 // We're here because we errored, which means this is the error that
@@ -616,7 +625,12 @@ impl<'d> UartRx<'d, Async> {
                 transfer,
                 poll_fn(|cx| {
                     self.dma_state.rx_err_waker.register(cx.waker());
-                    match self.dma_state.rx_errs.swap(0, Ordering::Relaxed) {
+                    let rx_errs = critical_section::with(|_| {
+                        let val = self.dma_state.rx_errs.load(Ordering::Relaxed);
+                        self.dma_state.rx_errs.store(0, Ordering::Relaxed);
+                        val
+                    });
+                    match rx_errs {
                         0 => Poll::Pending,
                         e => Poll::Ready(Uartris(e as u32)),
                     }
@@ -629,7 +643,11 @@ impl<'d> UartRx<'d, Async> {
                 Either::First(()) => {
                     // We're here because the DMA finished, BUT if an error occurred on the LAST
                     // byte, then we may still need to grab the error state!
-                    Uartris(self.dma_state.rx_errs.swap(0, Ordering::Relaxed) as u32)
+                    Uartris(critical_section::with(|_| {
+                        let val = self.dma_state.rx_errs.load(Ordering::Relaxed);
+                        self.dma_state.rx_errs.store(0, Ordering::Relaxed);
+                        val
+                    }) as u32)
                 }
                 Either::Second(e) => {
                     // We're here because we errored, which means this is the error that