arm: cache: define ARCH_DMA_MINALIGN for DMA buffer alignment

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>

arch/arm/include/asm/cache.h

@@ -42,4 +42,15 @@ static inline void invalidate_l2_cache(void)
 void l2_cache_enable(void);
 void l2_cache_disable(void);
 
+/*
+ * The current upper bound for ARM L1 data cache line sizes is 64 bytes.  We
+ * use that value for aligning DMA buffers unless the board config has specified
+ * an alternate cache line size.
+ */
+#ifdef CONFIG_SYS_CACHELINE_SIZE
+#define ARCH_DMA_MINALIGN	CONFIG_SYS_CACHELINE_SIZE
+#else
+#define ARCH_DMA_MINALIGN	64
+#endif
+
 #endif /* _ASM_CACHE_H */