rtio: Make rtio_mpsc.h C++ friendly

C++ requires casting void * as the implicit cast isn't enough and
the C++ sample app fails to build without duplicating type information
here. Do that, and wrap it in extern C allowing the C++ to include
rtio_mpsc.h directly or indirectly.

Signed-off-by: Tom Burdick <[email protected]>

Author: teburd

include/zephyr/rtio/rtio_mpsc.h

@@ -14,6 +14,10 @@
 #include <zephyr/sys/atomic.h>
 #include <zephyr/kernel.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * @brief RTIO Multiple Producer Single Consumer (MPSC) Queue API
  * @defgroup rtio_mpsc RTIO MPSC API
@@ -94,7 +98,7 @@ static inline void rtio_mpsc_push(struct rtio_mpsc *q, struct rtio_mpsc_node *n)
 	atomic_ptr_set(&n->next, NULL);
 
 	key = arch_irq_lock();
-	prev = atomic_ptr_set(&q->head, n);
+	prev = (struct rtio_mpsc_node *)atomic_ptr_set(&q->head, n);
 	atomic_ptr_set(&prev->next, n);
 	arch_irq_unlock(key);
 }
@@ -109,7 +113,7 @@ static inline struct rtio_mpsc_node *rtio_mpsc_pop(struct rtio_mpsc *q)
 {
 	struct rtio_mpsc_node *head;
 	struct rtio_mpsc_node *tail = q->tail;
-	struct rtio_mpsc_node *next = atomic_ptr_get(&tail->next);
+	struct rtio_mpsc_node *next = (struct rtio_mpsc_node *)atomic_ptr_get(&tail->next);
 
 	/* Skip over the stub/sentinel */
 	if (tail == &q->stub) {
@@ -119,7 +123,7 @@ static inline struct rtio_mpsc_node *rtio_mpsc_pop(struct rtio_mpsc *q)
 
 		q->tail = next;
 		tail = next;
-		next = atomic_ptr_get(&next->next);
+		next = (struct rtio_mpsc_node *)atomic_ptr_get(&next->next);
 	}
 
 	/* If next is non-NULL then a valid node is found, return it */
@@ -128,7 +132,7 @@ static inline struct rtio_mpsc_node *rtio_mpsc_pop(struct rtio_mpsc *q)
 		return tail;
 	}
 
-	head = atomic_ptr_get(&q->head);
+	head = (struct rtio_mpsc_node *)atomic_ptr_get(&q->head);
 
 	/* If next is NULL, and the tail != HEAD then the queue has pending
 	 * updates that can't yet be accessed.
@@ -139,7 +143,7 @@ static inline struct rtio_mpsc_node *rtio_mpsc_pop(struct rtio_mpsc *q)
 
 	rtio_mpsc_push(q, &q->stub);
 
-	next = atomic_ptr_get(&tail->next);
+	next = (struct rtio_mpsc_node *)atomic_ptr_get(&tail->next);
 
 	if (next != NULL) {
 		q->tail = next;
@@ -153,4 +157,9 @@ static inline struct rtio_mpsc_node *rtio_mpsc_pop(struct rtio_mpsc *q)
  * @}
  */
 
+#ifdef __cplusplus
+}
+#endif
+
+
 #endif /* ZEPHYR_RTIO_MPSC_H_ */