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arch/c6x: add option to skip sync on DMA map and unmap 

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
later via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113442.76501.7673.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Mark Salter <msalter@redhat.com>
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 15:04:41 -08:00 committed by Linus Torvalds
parent 8c16a2e209
commit 64c596b59c
1 changed files with 10 additions and 4 deletions
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8
arch/c6x/kernel/dma.c
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@ -42,13 +42,16 @@ static dma_addr_t c6x_dma_map_page(struct device *dev, struct page *page,
{
dma_addr_t handle = virt_to_phys(page_address(page) + offset);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
c6x_dma_sync(handle, size, dir);
return handle;
}
static void c6x_dma_unmap_page(struct device *dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
c6x_dma_sync(handle, size, dir);
}
@ -60,6 +63,7 @@ static int c6x_dma_map_sg(struct device *dev, struct scatterlist *sglist,
for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
c6x_dma_sync(sg->dma_address, sg->length, dir);
}
@ -72,9 +76,11 @@ static void c6x_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
struct scatterlist *sg;
int i;
if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
return;
for_each_sg(sglist, sg, nents, i)
c6x_dma_sync(sg_dma_address(sg), sg->length, dir);
}
static void c6x_dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle,