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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: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexander Duyck 2016-12-14 15:05:09 -08:00 committed by Linus Torvalds
parent f50a2bd298
commit 6f77480961
1 changed files with 8 additions and 1 deletions
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9
arch/powerpc/kernel/dma.c
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@ -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);
__dma_sync_page(page, offset, size, dir);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
__dma_sync_page(page, offset, size, dir);
return page_to_phys(page) + offset + get_dma_offset(dev);
}