Index: sys/dev/ofw/ofw_bus_subr.h
===================================================================
--- sys/dev/ofw/ofw_bus_subr.h
+++ sys/dev/ofw/ofw_bus_subr.h
@@ -107,6 +107,7 @@
 /* Helper routine for checking compat prop */
 int ofw_bus_is_compatible(device_t, const char *);
 int ofw_bus_is_compatible_strict(device_t, const char *);
+int ofw_bus_node_is_compatible(phandle_t, const char *);
 
 /* 
  * Helper routine to search a list of compat properties.  The table is
Index: sys/dev/ofw/ofw_bus_subr.c
===================================================================
--- sys/dev/ofw/ofw_bus_subr.c
+++ sys/dev/ofw/ofw_bus_subr.c
@@ -45,6 +45,8 @@
 
 #include "ofw_bus_if.h"
 
+#define	OFW_COMPAT_LEN	255
+
 int
 ofw_bus_gen_setup_devinfo(struct ofw_bus_devinfo *obd, phandle_t node)
 {
@@ -178,7 +180,8 @@
 }
 
 static int
-ofw_bus_node_is_compatible(const char *compat, int len, const char *onecompat)
+ofw_bus_node_is_compatible_int(const char *compat, int len,
+    const char *onecompat)
 {
 	int onelen, l, ret;
 
@@ -203,6 +206,25 @@
 }
 
 int
+ofw_bus_node_is_compatible(phandle_t node, const char *compatstr)
+{
+	char compat[OFW_COMPAT_LEN];
+	int len, rv;
+
+	if ((len = OF_getproplen(node, "compatible")) <= 0)
+		return (0);
+
+	bzero(compat, OFW_COMPAT_LEN);
+
+	if (OF_getprop(node, "compatible", compat, OFW_COMPAT_LEN) < 0)
+		return (0);
+
+	rv = ofw_bus_node_is_compatible_int(compat, len, compatstr);
+
+	return (rv);
+}
+
+int
 ofw_bus_is_compatible(device_t dev, const char *onecompat)
 {
 	phandle_t node;
@@ -219,7 +241,7 @@
 	if ((len = OF_getproplen(node, "compatible")) <= 0)
 		return (0);
 
-	return (ofw_bus_node_is_compatible(compat, len, onecompat));
+	return (ofw_bus_node_is_compatible_int(compat, len, onecompat));
 }
 
 int
@@ -689,7 +711,7 @@
 	for (child = OF_child(node); child != 0; child = OF_peer(child)) {
 		len = OF_getprop_alloc(child, "compatible", 1, &compat);
 		if (len >= 0) {
-			ret = ofw_bus_node_is_compatible(compat, len,
+			ret = ofw_bus_node_is_compatible_int(compat, len,
 			    onecompat);
 			free(compat, M_OFWPROP);
 			if (ret != 0)
Index: sys/dev/uart/uart_cpu_powerpc.c
===================================================================
--- sys/dev/uart/uart_cpu_powerpc.c
+++ sys/dev/uart/uart_cpu_powerpc.c
@@ -35,6 +35,7 @@
 #include <machine/bus.h>
 #include <machine/ofw_machdep.h>
 
+#include <dev/ofw/ofw_bus_subr.h>
 #include <dev/ofw/openfirm.h>
 #include <dev/uart/uart.h>
 #include <dev/uart/uart_cpu.h>
@@ -163,14 +164,13 @@
 		return (ENXIO);
 	if (strcmp(buf, "serial") != 0)
 		return (ENXIO);
-	if (OF_getprop(input, "compatible", buf, sizeof(buf)) == -1)
-		return (ENXIO);
 
-	if (strncmp(buf, "chrp,es", 7) == 0) {
+	if (ofw_bus_node_is_compatible(input, "chrp,es")) {
 		class = &uart_z8530_class;
 		di->bas.regshft = 4;
 		di->bas.chan = 1;
-	} else if (strcmp(buf,"ns16550") == 0 || strcmp(buf,"ns8250") == 0) {
+	} else if (ofw_bus_node_is_compatible(input,"ns16550") ||
+	    ofw_bus_node_is_compatible(input,"ns8250")) {
 		class = &uart_ns8250_class;
 		di->bas.regshft = 0;
 		di->bas.chan = 0;