Add a function to retrieve a semaphore's counter value (#4066)

Author: bugadani

esp-preempt/src/semaphore.rs

@@ -32,6 +32,10 @@ impl SemaphoreInner {
             false
         }
     }
+
+    fn current_count(&mut self) -> u32 {
+        self.current
+    }
 }
 
 pub struct Semaphore {
@@ -84,6 +88,10 @@ impl Semaphore {
         Self::yield_loop_with_timeout(timeout_us, || self.try_take())
     }
 
+    pub fn current_count(&self) -> u32 {
+        self.inner.with(|sem| sem.current_count())
+    }
+
     pub fn give(&self) -> bool {
         self.inner.with(|sem| sem.try_give())
     }
@@ -112,6 +120,12 @@ impl SemaphoreImplementation for Semaphore {
         semaphore.give()
     }
 
+    unsafe fn current_count(semaphore: SemaphorePtr) -> u32 {
+        let semaphore = unsafe { Semaphore::from_ptr(semaphore) };
+
+        semaphore.current_count()
+    }
+
     unsafe fn try_take(semaphore: SemaphorePtr) -> bool {
         let semaphore = unsafe { Semaphore::from_ptr(semaphore) };
 

esp-radio-preempt-driver/src/semaphore.rs

@@ -11,6 +11,7 @@ unsafe extern "Rust" {
 
     fn esp_preempt_semaphore_take(semaphore: SemaphorePtr, timeout_us: Option<u32>) -> bool;
     fn esp_preempt_semaphore_give(semaphore: SemaphorePtr) -> bool;
+    fn esp_preempt_semaphore_current_count(semaphore: SemaphorePtr) -> u32;
 
     fn esp_preempt_semaphore_try_take(semaphore: SemaphorePtr) -> bool;
 }
@@ -51,6 +52,13 @@ pub trait SemaphoreImplementation {
     /// `semaphore` must be a pointer returned from [`Self::create`].
     unsafe fn give(semaphore: SemaphorePtr) -> bool;
 
+    /// Returns the semaphore's current counter value.
+    ///
+    /// # Safety
+    ///
+    /// `semaphore` must be a pointer returned from [`Self::create`].
+    unsafe fn current_count(semaphore: SemaphorePtr) -> u32;
+
     /// Attempts to decrement the semaphore's counter.
     ///
     /// If the counter is zero, this function must immediately return `false`.
@@ -93,6 +101,12 @@ macro_rules! register_semaphore_implementation {
             unsafe { <$t as $crate::semaphore::SemaphoreImplementation>::give(semaphore) }
         }
 
+        #[unsafe(no_mangle)]
+        #[inline]
+        fn esp_preempt_semaphore_current_count(semaphore: $crate::semaphore::SemaphorePtr) -> u32 {
+            unsafe { <$t as $crate::semaphore::SemaphoreImplementation>::current_count(semaphore) }
+        }
+
         #[unsafe(no_mangle)]
         #[inline]
         fn esp_preempt_semaphore_try_take(semaphore: $crate::semaphore::SemaphorePtr) -> bool {
@@ -157,6 +171,11 @@ impl SemaphoreHandle {
         unsafe { esp_preempt_semaphore_give(self.0) }
     }
 
+    /// Returns the current counter value.
+    pub fn current_count(&self) -> u32 {
+        unsafe { esp_preempt_semaphore_current_count(self.0) }
+    }
+
     /// Attempts to decrement the semaphore's counter.
     ///
     /// If the counter is zero, this function returns `false`.