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Groups > linux.kernel > #1507533

[net-next PATCH RFC 07/26] arch/c6x: Add option to skip sync on DMA map and unmap

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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: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: linux-c6x-dev@linux-c6x.org
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/c6x/kernel/dma.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/c6x/kernel/dma.c b/arch/c6x/kernel/dma.c
index db4a6a3..d28df74 100644
--- a/arch/c6x/kernel/dma.c
+++ b/arch/c6x/kernel/dma.c
@@ -42,14 +42,17 @@ 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);
 
-	c6x_dma_sync(handle, size, dir);
+	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)
 {
-	c6x_dma_sync(handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		c6x_dma_sync(handle, size, dir);
 }
 
 static int c6x_dma_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -60,7 +63,8 @@ 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);
-		c6x_dma_sync(sg->dma_address, sg->length, dir);
+		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			c6x_dma_sync(sg->dma_address, sg->length, dir);
 	}
 
 	return nents;
@@ -72,8 +76,10 @@ static void c6x_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	struct scatterlist *sg;
 	int i;
 
-	for_each_sg(sglist, sg, nents, i)
-		c6x_dma_sync(sg_dma_address(sg), sg->length, dir);
+	for_each_sg(sglist, sg, nents, i) {
+		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			c6x_dma_sync(sg_dma_address(sg), sg->length, dir);
+	}
 
 }
 

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[net-next PATCH RFC 00/26] Add support for DMA writable pages being  writable by the network stack Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  [net-next PATCH RFC 26/26] igb: Revert "igb: Revert support for  build_skb in igb" Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  [net-next PATCH RFC 07/26] arch/c6x: Add option to skip sync on DMA  map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  [net-next PATCH RFC 10/26] arch/m68k: Add option to skip DMA sync  as a part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  [net-next PATCH RFC 13/26] arch/mips: Add option to skip DMA sync  as a part of map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  [net-next PATCH RFC 12/26] arch/microblaze: Add option to skip DMA  sync as a part of map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  Re: [net-next PATCH RFC 01/26] swiotlb: Drop unused function  swiotlb_map_sg Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2016-10-24 20:20 +0200
  [net-next PATCH RFC 02/26] swiotlb: Add support for  DMA_ATTR_SKIP_CPU_SYNC Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:20 +0200
  [net-next PATCH RFC 01/26] swiotlb: Drop unused function  swiotlb_map_sg Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:20 +0200
  [net-next PATCH RFC 09/26] arch/hexagon: Add option to skip DMA  sync as a part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:20 +0200
  [net-next PATCH RFC 08/26] arch/frv: Add option to skip sync on DMA  map Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:20 +0200
  [net-next PATCH RFC 15/26] arch/openrisc: Add option to skip DMA  sync as a part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:20 +0200
  [net-next PATCH RFC 03/26] arch/arc: Add option to skip sync on DMA  mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:20 +0200

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