diff --git a/tools/dtoc/dtb_platdata.py b/tools/dtoc/dtb_platdata.py
index cfca45b..dc9c0d9 100644
--- a/tools/dtoc/dtb_platdata.py
+++ b/tools/dtoc/dtb_platdata.py
@@ -190,6 +190,16 @@ class DtbPlatdata(object):
         self._lines = []
         return lines
 
+    def out_header(self):
+        """Output a message indicating that this is an auto-generated file"""
+        self.out('''/*
+ * DO NOT MODIFY
+ *
+ * This file was generated by dtoc from a .dtb (device tree binary) file.
+ */
+
+''')
+
     def get_phandle_argc(self, prop, node_name):
         """Check if a node contains phandles
 
@@ -410,6 +420,7 @@ class DtbPlatdata(object):
         definitions for node in self._valid_nodes. See the documentation in
         README.of-plat for more information.
         """
+        self.out_header()
         self.out('#include <stdbool.h>\n')
         self.out('#include <libfdt.h>\n')
 
@@ -512,6 +523,7 @@ class DtbPlatdata(object):
         See the documentation in doc/driver-model/of-plat.txt for more
         information.
         """
+        self.out_header()
         self.out('#include <common.h>\n')
         self.out('#include <dm.h>\n')
         self.out('#include <dt-structs.h>\n')