--- a/arch/arm/mach-cns3xxx/Makefile
+++ b/arch/arm/mach-cns3xxx/Makefile
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
+ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include
+
 obj-$(CONFIG_ARCH_CNS3XXX)		+= cns3xxx.o
 cns3xxx-y				+= core.o pm.o
 cns3xxx-$(CONFIG_ATAGS)			+= devices.o
