Index: head/sys/dev/fdt/simplebus.h
===================================================================
--- head/sys/dev/fdt/simplebus.h
+++ head/sys/dev/fdt/simplebus.h
@@ -47,6 +47,8 @@
 
 	struct simplebus_range *ranges;
 	int nranges;
+#define	SB_FLAG_NO_RANGES	(1 << 0) /* Bus doesn't have ranges property */
+	int flags;
 
 	pcell_t acells, scells;
 };
@@ -63,4 +65,7 @@
     struct simplebus_devinfo *di);
 int simplebus_fill_ranges(phandle_t node,
     struct simplebus_softc *sc);
+
+int simplebus_attach(device_t dev);
+
 #endif	/* _FDT_SIMPLEBUS_H */
Index: head/sys/dev/fdt/simplebus.c
===================================================================
--- head/sys/dev/fdt/simplebus.c
+++ head/sys/dev/fdt/simplebus.c
@@ -46,7 +46,6 @@
  * Bus interface.
  */
 static int		simplebus_probe(device_t dev);
-static int		simplebus_attach(device_t dev);
 static struct resource *simplebus_alloc_resource(device_t, device_t, int,
     int *, rman_res_t, rman_res_t, rman_res_t, u_int);
 static void		simplebus_probe_nomatch(device_t bus, device_t child);
@@ -134,7 +133,7 @@
 	return (BUS_PROBE_GENERIC);
 }
 
-static int
+int
 simplebus_attach(device_t dev)
 {
 	struct		simplebus_softc *sc;
@@ -142,7 +141,8 @@
 
 	sc = device_get_softc(dev);
 	simplebus_init(dev, 0);
-	if (simplebus_fill_ranges(sc->node, sc) < 0) {
+	if ((sc->flags & SB_FLAG_NO_RANGES) == 0 &&
+	    simplebus_fill_ranges(sc->node, sc) < 0) {
 		device_printf(dev, "could not get ranges\n");
 		return (ENXIO);
 	}