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authorAlexander Duyck <alexander.h.duyck@intel.com>2016-12-14 15:05:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-14 16:04:07 -0800
commit6f774809612d1f1fc800b452ee1ef447a277ec9d (patch)
treef2bb7f35ceb5ec707cdb8ddc9b8ec95edcd54bf9 /arch/powerpc/kernel
parentf50a2bd298b47e1957f67f794aed90f2c3bd9a10 (diff)
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>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/dma.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index e64a6016fba7..6877e3fa95bb 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -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);
}