arch/hexagon: Add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to avoid invoking cache line invalidation if the driver will just handle it later via a sync_for_cpu or sync_for_device call. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Alexander Duyck <[email protected]> Cc: Richard Kuo <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
kyagi · Dec 15, 2016 · b8a346d · b8a346d
1 parent 34f8be7
commit b8a346d
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/arch/hexagon/kernel/dma.c b/arch/hexagon/kernel/dma.c
@@ -119,6 +119,9 @@ static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg,
 
 		s->dma_length = s->length;
 
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
 		flush_dcache_range(dma_addr_to_virt(s->dma_address),
 				   dma_addr_to_virt(s->dma_address + s->length));
 	}
@@ -180,7 +183,8 @@ static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
 	if (!check_addr("map_single", dev, bus, size))
 		return bad_dma_address;
 
-	dma_sync(dma_addr_to_virt(bus), size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_sync(dma_addr_to_virt(bus), size, dir);
 
 	return bus;
 }