diff --git a/include/asm-arm/io.h b/include/asm-arm/io.h
index 8261ff9..1d3caa4 100644
--- a/include/asm-arm/io.h
+++ b/include/asm-arm/io.h
@@ -259,9 +259,11 @@
 #define BIOVEC_MERGEABLE(vec1, vec2)	\
 	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 
+#ifdef CONFIG_MMU
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE
 extern int valid_phys_addr_range(unsigned long addr, size_t size);
 extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
+#endif
 
 /*
  * Convert a physical pointer to a virtual kernel pointer for /dev/mem