[net-next PATCH 04/27] arch/arc: Add option to skip sync on DMA mapping

[Alexander Duyck]

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.

Cc: Vineet Gupta <vgu...@synopsys.com>
Cc: linux-snps-...@lists.infradead.org
Signed-off-by: Alexander Duyck <alexander.h.du...@intel.com>
---
 arch/arc/mm/dma.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 20afc65..6303c34 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -133,7 +133,10 @@ static dma_addr_t arc_dma_map_page(struct device *dev, 
struct page *page,
                unsigned long attrs)
 {
        phys_addr_t paddr = page_to_phys(page) + offset;
-       _dma_cache_sync(paddr, size, dir);
+
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+               _dma_cache_sync(paddr, size, dir);
+
        return plat_phys_to_dma(dev, paddr);
 }