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Commit 7f332fc1 authored by Takeshi Kihara's avatar Takeshi Kihara Committed by Will Deacon
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arm64: Add support for DMA_ATTR_SKIP_CPU_SYNC attribute to swiotlb 



This patch adds support for DMA_ATTR_SKIP_CPU_SYNC attribute for
dma_{un}map_{page,sg} functions family to swiotlb.

DMA_ATTR_SKIP_CPU_SYNC allows platform code to skip synchronization of
the CPU cache for the given buffer assuming that it has been already
transferred to 'device' domain.

Ported from IOMMU .{un}map_{sg,page} ops.

Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarTakeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent ec6d06ef

arch/arm64/mm/dma-mapping.c

+8 −4
Original line number Diff line number Diff line
@@ -211,7 +211,8 @@ static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page, 
	dma_addr_t dev_addr;



	dev_addr = swiotlb_map_page(dev, page, offset, size, dir, attrs);

	if (!is_device_dma_coherent(dev))

	if (!is_device_dma_coherent(dev) &&

	    (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)

		__dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);



	return dev_addr;
@@ -222,7 +223,8 @@ static void __swiotlb_unmap_page(struct device *dev, dma_addr_t dev_addr, 
				 size_t size, enum dma_data_direction dir,

				 unsigned long attrs)

{

	if (!is_device_dma_coherent(dev))

	if (!is_device_dma_coherent(dev) &&

	    (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)

		__dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);

	swiotlb_unmap_page(dev, dev_addr, size, dir, attrs);

}
@@ -235,7 +237,8 @@ static int __swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl, 
	int i, ret;



	ret = swiotlb_map_sg_attrs(dev, sgl, nelems, dir, attrs);

	if (!is_device_dma_coherent(dev))

	if (!is_device_dma_coherent(dev) &&

	    (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)

		for_each_sg(sgl, sg, ret, i)

			__dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),

				       sg->length, dir);
@@ -251,7 +254,8 @@ static void __swiotlb_unmap_sg_attrs(struct device *dev, 
	struct scatterlist *sg;

	int i;



	if (!is_device_dma_coherent(dev))

	if (!is_device_dma_coherent(dev) &&

	    (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)

		for_each_sg(sgl, sg, nelems, i)

			__dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),

					 sg->length, dir);