[net-next PATCH RFC 12/26] arch/microblaze: Add option to skip DMA sync as a part of map and unmap

[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
via a sync_for_cpu or sync_for_device call.

Cc: Michal Simek <mon...@monstr.eu>
Signed-off-by: Alexander Duyck <alexander.h.du...@intel.com>
---
 arch/microblaze/kernel/dma.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/microblaze/kernel/dma.c b/arch/microblaze/kernel/dma.c
index ec04dc1..818daf2 100644
--- a/arch/microblaze/kernel/dma.c
+++ b/arch/microblaze/kernel/dma.c
@@ -61,6 +61,10 @@ static int dma_direct_map_sg(struct device *dev, struct 
scatterlist *sgl,
        /* FIXME this part of code is untested */
        for_each_sg(sgl, sg, nents, i) {
                sg->dma_address = sg_phys(sg);
+
+               if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+                       continue;
+
                __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
                                                        sg->length, direction);
        }
@@ -80,7 +84,8 @@ static inline dma_addr_t dma_direct_map_page(struct device 
*dev,
                                             enum dma_data_direction direction,
                                             unsigned long attrs)
 {
-       __dma_sync(page_to_phys(page) + offset, size, direction);
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+               __dma_sync(page_to_phys(page) + offset, size, direction);
        return page_to_phys(page) + offset;
 }
 
@@ -95,7 +100,8 @@ static inline void dma_direct_unmap_page(struct device *dev,
  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
  * dma_address is physical address
  */
-       __dma_sync(dma_address, size, direction);
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+               __dma_sync(dma_address, size, direction);
 }
 
 static inline void