5 files changed, 45 insertions, 5 deletions

diff --git a/embassy-hal-internal/Cargo.toml b/embassy-hal-internal/Cargo.toml
index 11dcc2466..c2e0bd30f 100644
--- a/embassy-hal-internal/Cargo.toml
+++ b/embassy-hal-internal/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "embassy-hal-internal"
 version = "0.3.0"
-edition = "2021"
+edition = "2024"
 license = "MIT OR Apache-2.0"
 description = "Internal implementation details for Embassy HALs. DO NOT USE DIRECTLY."
 repository = "https://github.com/embassy-rs/embassy"
diff --git a/embassy-hal-internal/src/atomic_ring_buffer.rs b/embassy-hal-internal/src/atomic_ring_buffer.rs
index 00b7a1249..8c3889b85 100644
--- a/embassy-hal-internal/src/atomic_ring_buffer.rs
+++ b/embassy-hal-internal/src/atomic_ring_buffer.rs
@@ -133,6 +133,18 @@ impl RingBuffer {
         self.len.load(Ordering::Relaxed)
     }
 
+    /// Return number of items available to read.
+    pub fn available(&self) -> usize {
+        let end = self.end.load(Ordering::Relaxed);
+        let len = self.len.load(Ordering::Relaxed);
+        let start = self.start.load(Ordering::Relaxed);
+        if end >= start {
+            end - start
+        } else {
+            2 * len - start + end
+        }
+    }
+
     /// Check if buffer is full.
     pub fn is_full(&self) -> bool {
         let len = self.len.load(Ordering::Relaxed);
@@ -142,6 +154,11 @@ impl RingBuffer {
         self.wrap(start + len) == end
     }
 
+    /// Check if buffer is at least half full.
+    pub fn is_half_full(&self) -> bool {
+        self.available() >= self.len.load(Ordering::Relaxed) / 2
+    }
+
     /// Check if buffer is empty.
     pub fn is_empty(&self) -> bool {
         let start = self.start.load(Ordering::Relaxed);
@@ -394,6 +411,7 @@ mod tests {
             rb.init(b.as_mut_ptr(), 4);
 
             assert_eq!(rb.is_empty(), true);
+            assert_eq!(rb.is_half_full(), false);
             assert_eq!(rb.is_full(), false);
 
             rb.writer().push(|buf| {
@@ -406,6 +424,7 @@ mod tests {
             });
 
             assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), true);
 
             rb.writer().push(|buf| {
@@ -415,6 +434,7 @@ mod tests {
             });
 
             assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), true);
 
             rb.reader().pop(|buf| {
@@ -424,6 +444,7 @@ mod tests {
             });
 
             assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), false);
 
             rb.reader().pop(|buf| {
@@ -432,6 +453,7 @@ mod tests {
             });
 
             assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), false);
 
             rb.reader().pop(|buf| {
@@ -447,6 +469,7 @@ mod tests {
             });
 
             assert_eq!(rb.is_empty(), true);
+            assert_eq!(rb.is_half_full(), false);
             assert_eq!(rb.is_full(), false);
 
             rb.reader().pop(|buf| {
@@ -460,14 +483,28 @@ mod tests {
                 1
             });
 
+            assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), false);
+            assert_eq!(rb.is_full(), false);
+
             rb.writer().push(|buf| {
                 assert_eq!(3, buf.len());
                 buf[0] = 11;
-                buf[1] = 12;
-                2
+                1
+            });
+
+            assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
+            assert_eq!(rb.is_full(), false);
+
+            rb.writer().push(|buf| {
+                assert_eq!(2, buf.len());
+                buf[0] = 12;
+                1
             });
 
             assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), false);
 
             rb.writer().push(|buf| {
@@ -477,6 +514,7 @@ mod tests {
             });
 
             assert_eq!(rb.is_empty(), false);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), true);
         }
     }
@@ -490,6 +528,7 @@ mod tests {
             rb.init(b.as_mut_ptr(), b.len());
 
             assert_eq!(rb.is_empty(), true);
+            assert_eq!(rb.is_half_full(), true);
             assert_eq!(rb.is_full(), true);
 
             rb.writer().push(|buf| {
diff --git a/embassy-hal-internal/src/interrupt.rs b/embassy-hal-internal/src/interrupt.rs
index 5e64dce9d..ce6057e2d 100644
--- a/embassy-hal-internal/src/interrupt.rs
+++ b/embassy-hal-internal/src/interrupt.rs
@@ -1,6 +1,6 @@
 //! Interrupt handling for cortex-m devices.
 use core::mem;
-use core::sync::atomic::{compiler_fence, Ordering};
+use core::sync::atomic::{Ordering, compiler_fence};
 
 use cortex_m::interrupt::InterruptNumber;
 use cortex_m::peripheral::NVIC;
diff --git a/embassy-hal-internal/src/lib.rs b/embassy-hal-internal/src/lib.rs
index 7addb71e2..729f97f0c 100644
--- a/embassy-hal-internal/src/lib.rs
+++ b/embassy-hal-internal/src/lib.rs
@@ -1,5 +1,6 @@
 #![no_std]
 #![allow(clippy::new_without_default)]
+#![allow(unsafe_op_in_unsafe_fn)]
 #![doc = include_str!("../README.md")]
 #![warn(missing_docs)]
 
diff --git a/embassy-hal-internal/src/macros.rs b/embassy-hal-internal/src/macros.rs
index ce72ded5c..0fcca2baf 100644
--- a/embassy-hal-internal/src/macros.rs
+++ b/embassy-hal-internal/src/macros.rs
@@ -58,7 +58,7 @@ macro_rules! peripherals_struct {
             ///Returns all the peripherals *once*
             #[inline]
             pub(crate) fn take_with_cs(_cs: critical_section::CriticalSection) -> Self {
-                #[no_mangle]
+                #[unsafe(no_mangle)]
                 static mut _EMBASSY_DEVICE_PERIPHERALS: bool = false;
 
                 // safety: OK because we're inside a CS.