diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
index dade7c4..c36c14c 100644
--- a/drivers/dma/dma-jz4780.c
+++ b/drivers/dma/dma-jz4780.c
@@ -396,7 +396,7 @@
 	return vchan_tx_prep(&jzchan->vchan, &desc->vdesc, flags);
 }
 
-struct dma_async_tx_descriptor *jz4780_dma_prep_dma_memcpy(
+static struct dma_async_tx_descriptor *jz4780_dma_prep_dma_memcpy(
 	struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 	size_t len, unsigned long flags)
 {