diff --git a/sys/arm/at91/at91.c b/sys/arm/at91/at91.c
index 2c44857ec2bc..c983e531c01b 100644
--- a/sys/arm/at91/at91.c
+++ b/sys/arm/at91/at91.c
@@ -50,6 +50,8 @@ static struct at91_softc *at91_softc;
 
 static void at91_eoi(void *);
 
+uint32_t at91_master_clock = AT91C_MASTER_CLOCK;
+
 static int
 at91_bs_map(void *t, bus_addr_t bpa, bus_size_t size, int flags,
     bus_space_handle_t *bshp)
diff --git a/sys/arm/at91/at91var.h b/sys/arm/at91/at91var.h
index 3a323392e064..3f82dd76392d 100644
--- a/sys/arm/at91/at91var.h
+++ b/sys/arm/at91/at91var.h
@@ -43,4 +43,6 @@ struct at91_ivar {
 	struct resource_list resources;
 };
 
+extern uint32_t at91_master_clock;
+
 #endif /* _AT91VAR_H_ */