[ARM] Optionally flush entire dcache from v6_dma_flush_range

If CACHE_FLUSH_RANGE_LIMIT is defined, then the entire dcache will
be flushed if the requested range is larger than this limit.

Change-Id: I29277d645a9d6716b1952cf3b870c78496261dd0
Signed-off-by: Arve Hjønnevåg <arve@android.com>
diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S
index 73b4a8b..6b5441d 100644
--- a/arch/arm/mm/cache-v6.S
+++ b/arch/arm/mm/cache-v6.S
@@ -272,6 +272,11 @@
  *	- end     - virtual end address of region
  */
 ENTRY(v6_dma_flush_range)
+#ifdef CONFIG_CACHE_FLUSH_RANGE_LIMIT
+	sub	r2, r1, r0
+	cmp	r2, #CONFIG_CACHE_FLUSH_RANGE_LIMIT
+	bhi	v6_dma_flush_dcache_all
+#endif
 #ifdef CONFIG_DMA_CACHE_RWFO
 	ldrb	r2, [r0]		@ read for ownership
 	strb	r2, [r0]		@ write for ownership
@@ -294,6 +299,18 @@
 	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer
 	mov	pc, lr
 
+#ifdef CONFIG_CACHE_FLUSH_RANGE_LIMIT
+v6_dma_flush_dcache_all:
+	mov	r0, #0
+#ifdef HARVARD_CACHE
+	mcr	p15, 0, r0, c7, c14, 0		@ D cache clean+invalidate
+#else
+	mcr	p15, 0, r0, c7, c15, 0		@ Cache clean+invalidate
+#endif
+	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer
+	mov	pc, lr
+#endif
+
 /*
  *	dma_map_area(start, size, dir)
  *	- start	- kernel virtual start address