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arch/metag: add option to skip DMA sync as a part of 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
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113503.76501.80809.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: James Hogan <james.hogan@imgtec.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 15:04:52 -08:00 committed by Linus Torvalds
parent 5140d2344f
commit 38bdbdc7e3
1 changed files with 13 additions and 3 deletions
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14
arch/metag/kernel/dma.c
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@ -484,8 +484,9 @@ static dma_addr_t metag_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction direction, unsigned long attrs)
{
dma_sync_for_device((void *)(page_to_phys(page) + offset), size,
direction);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_sync_for_device((void *)(page_to_phys(page) + offset),
size, direction);
return page_to_phys(page) + offset;
}
@ -493,6 +494,7 @@ static void metag_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
size_t size, enum dma_data_direction direction,
unsigned long attrs)
{
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
}
@ -507,6 +509,10 @@ static int metag_dma_map_sg(struct device *dev, struct scatterlist *sglist,
BUG_ON(!sg_page(sg));
sg->dma_address = sg_phys(sg);
if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
continue;
dma_sync_for_device(sg_virt(sg), sg->length, direction);
}
@ -525,6 +531,10 @@ static void metag_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
BUG_ON(!sg_page(sg));
sg->dma_address = sg_phys(sg);
if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
continue;
dma_sync_for_cpu(sg_virt(sg), sg->length, direction);
}
}