diff --git a/include/dma-dir.h b/include/dma-dir.h
index ba107f1..970764c 100644
--- a/include/dma-dir.h
+++ b/include/dma-dir.h
@@ -1,6 +1,11 @@
+#ifndef __DMA_DIR_H
+#define __DMA_DIR_H
+
 enum dma_data_direction {
 	DMA_BIDIRECTIONAL = 0,
 	DMA_TO_DEVICE = 1,
 	DMA_FROM_DEVICE = 2,
 	DMA_NONE = 3,
 };
+
+#endif /* __DMA_DIR_H */