feat(ble_mesh): add cas operation for bt_mesh_atomic_val_t

Author: forx157

components/bt/esp_ble_mesh/common/atomic.c

@@ -13,7 +13,7 @@
 /*
  * SPDX-FileCopyrightText: 2016 Intel Corporation
  * SPDX-FileCopyrightText: 2011-2014 Wind River Systems, Inc.
- * SPDX-FileContributor: 2018-2021 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileContributor: 2018-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -170,4 +170,21 @@ bt_mesh_atomic_val_t bt_mesh_atomic_inc(bt_mesh_atomic_t *target)
     return ret;
 }
 
+bool bt_mesh_atomic_campare_and_set(bt_mesh_atomic_t *target, bt_mesh_atomic_val_t excepted, bt_mesh_atomic_val_t new_val)
+{
+    bt_mesh_atomic_val_t ret = 0;
+
+    bt_mesh_atomic_lock();
+
+    ret = *target;
+    if (*target == excepted) {
+        *target = new_val;
+        bt_mesh_atomic_unlock();
+        return true;
+    }
+
+    bt_mesh_atomic_unlock();
+    return false;
+}
+
 #endif /* #ifndef CONFIG_ATOMIC_OPERATIONS_BUILTIN */

components/bt/esp_ble_mesh/common/include/mesh/atomic.h

@@ -147,6 +147,33 @@ static inline bt_mesh_atomic_val_t bt_mesh_atomic_and(bt_mesh_atomic_t *target,
 extern bt_mesh_atomic_val_t bt_mesh_atomic_and(bt_mesh_atomic_t *target, bt_mesh_atomic_val_t value);
 #endif
 
+/**
+ * @brief Atomic CAS operation.
+ *
+ * This compares the contents of @a *target
+ * with the contents of @a excepted. If equal,
+ * the operation is a read-modify-write operation
+ * that writes @a new_val into @a *target and return true.
+ * If they are not equal, the operation is a read
+ * and return false.
+ *
+ * @param target Address of atomic variable.
+ * @param excepted Value of excepted.
+ * @param new_val Write value if compare sunncess.
+ *
+ * @return
+ *         - true: write operation succeeded.
+ *         - false: write operation failed.
+ */
+#ifdef CONFIG_ATOMIC_OPERATIONS_BUILTIN
+static inline bool bt_mesh_atomic_campare_and_set(bt_mesh_atomic_t *target, bt_mesh_atomic_val_t excepted, bt_mesh_atomic_val_t new_val)
+{
+    return __atomic_compare_exchange_n(target, &excepted, &new_val, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+}
+#else
+extern bool bt_mesh_atomic_campare_and_set(bt_mesh_atomic_t *target, bt_mesh_atomic_val_t excepted, bt_mesh_atomic_val_t new_val);
+#endif
+
 /**
  * @cond INTERNAL_HIDDEN
  */