--- a/sys/dev/disk/nata/chipsets/ata-marvell.c
+++ b/sys/dev/disk/nata/chipsets/ata-marvell.c
@@ -204,6 +204,9 @@ ata_marvell_edma_allocate(device_t dev)
     struct ata_channel *ch = device_get_softc(dev);
     u_int64_t work;
     int i;
 
+    if (ch->dma == NULL)
+	return ENXIO;
+
     work = ch->dma->work_bus;
     /* clear work area */
     bzero(ch->dma->work, 1024+256);