diff --git a/arch/powerpc/boot/devtree.c b/arch/powerpc/boot/devtree.c
index c995155..ae8b886 100644
--- a/arch/powerpc/boot/devtree.c
+++ b/arch/powerpc/boot/devtree.c
@@ -74,6 +74,8 @@
 		if (bus > 0)
 			setprop_val(devp, "bus-frequency", bus);
 	}
+
+	timebase_period_ns = 1000000000 / tb;
 }
 
 void dt_fixup_clock(const char *path, u32 freq)