diff --git a/arch/powerpc/sysdev/fsl_rmu.c b/arch/powerpc/sysdev/fsl_rmu.c
index 88b35a3dcdc599b01c37da944ba3f8481215d6cc..8b0ebf3940d29aa4df01c2dcd82e6907768d9bd6 100644
--- a/arch/powerpc/sysdev/fsl_rmu.c
+++ b/arch/powerpc/sysdev/fsl_rmu.c
@@ -756,15 +756,13 @@ fsl_open_outb_mbox(struct rio_mport *mport, void *dev_id, int mbox, int entries)
 	}
 
 	/* Initialize outbound message descriptor ring */
-	rmu->msg_tx_ring.virt = dma_alloc_coherent(priv->dev,
+	rmu->msg_tx_ring.virt = dma_zalloc_coherent(priv->dev,
 				rmu->msg_tx_ring.size * RIO_MSG_DESC_SIZE,
 				&rmu->msg_tx_ring.phys, GFP_KERNEL);
 	if (!rmu->msg_tx_ring.virt) {
 		rc = -ENOMEM;
 		goto out_dma;
 	}
-	memset(rmu->msg_tx_ring.virt, 0,
-			rmu->msg_tx_ring.size * RIO_MSG_DESC_SIZE);
 	rmu->msg_tx_ring.tx_slot = 0;
 
 	/* Point dequeue/enqueue pointers at first entry in ring */