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Commit 6f774809 authored by Alexander Duyck's avatar Alexander Duyck Committed by Linus Torvalds
Browse files

arch/powerpc: 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
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113534.76501.86492.stgit@ahduyck-blue-test.jf.intel.com


Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Acked-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f50a2bd2

arch/powerpc/kernel/dma.c

+8 −1
Original line number Diff line number Diff line
@@ -203,6 +203,10 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, 
	for_each_sg(sgl, sg, nents, i) {

		sg->dma_address = sg_phys(sg) + get_dma_offset(dev);

		sg->dma_length = sg->length;



		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)

			continue;



		__dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);

	}
@@ -235,7 +239,10 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev, 
					     unsigned long attrs)

{

	BUG_ON(dir == DMA_NONE);



	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))

		__dma_sync_page(page, offset, size, dir);



	return page_to_phys(page) + offset + get_dma_offset(dev);

}