diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 23c2e8e..d0ee74b 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -188,7 +188,7 @@
  * translation for translating DMA addresses.  Use the driver
  * DMA support - see dma-mapping.h.
  */
-static inline unsigned long virt_to_phys(void *x)
+static inline unsigned long virt_to_phys(const volatile void *x)
 {
 	return __virt_to_phys((unsigned long)(x));
 }