[mm PATCH v3 15/23] arch/powerpc: Add option to skip DMA sync as a part of mapping
From: Alexander Duyck <hidden>
Date: 2016-11-10 17:36:58
Also in:
linux-mm, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
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. Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Signed-off-by: Alexander Duyck <redacted> --- arch/powerpc/kernel/dma.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index e64a601..6877e3f 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); } --
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