diff --git a/src/pdr.c b/src/pdr.c
index 72cab7e..ee699c7 100644
--- a/src/pdr.c
+++ b/src/pdr.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "pdr.h"
 #include "platform.h"
 #include <assert.h>