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arch/m68k: 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
later via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113457.76501.77603.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Alexander Duyck 2016-12-14 15:04:49 -08:00 committed by Linus Torvalds
parent b8a346dd47
commit 5140d2344f
1 changed files with 7 additions and 1 deletions
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8
arch/m68k/kernel/dma.c
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@ -134,7 +134,9 @@ static dma_addr_t m68k_dma_map_page(struct device *dev, struct page *page,
{
dma_addr_t handle = page_to_phys(page) + offset;
dma_sync_single_for_device(dev, handle, size, dir);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_sync_single_for_device(dev, handle, size, dir);
return handle;
}
@ -146,6 +148,10 @@ static int m68k_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)
continue;
dma_sync_single_for_device(dev, sg->dma_address, sg->length,
dir);
}