diff --git a/arch/blackfin/include/asm/io.h b/arch/blackfin/include/asm/io.h
index 7dc77a21fdf33aeb2f94fc42ad97db7c1f9447a0..e7591ea2a0e08b85431a95dae6a152765c8cf74b 100644
--- a/arch/blackfin/include/asm/io.h
+++ b/arch/blackfin/include/asm/io.h
@@ -108,6 +108,8 @@ static inline unsigned int readl(const volatile void __iomem *addr)
 #define iowrite16(val,X)		writew(val,X)
 #define iowrite32(val,X)		writel(val,X)
 
+#define mmiowb() wmb()
+
 #define IO_SPACE_LIMIT 0xffffffff
 
 /* Values for nocacheflag and cmode */