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Subject[net-next PATCH 14/27] arch/mips: Add option to skip DMA sync as a part of 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
via a sync_for_cpu or sync_for_device call.

Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
arch/mips/loongson64/common/dma-swiotlb.c | 2 +-
arch/mips/mm/dma-default.c | 8 +++++---
2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/mips/loongson64/common/dma-swiotlb.c b/arch/mips/loongson64/common/dma-swiotlb.c
index 1a80b6f..aab4fd6 100644
--- a/arch/mips/loongson64/common/dma-swiotlb.c
+++ b/arch/mips/loongson64/common/dma-swiotlb.c
@@ -61,7 +61,7 @@ static int loongson_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir,
unsigned long attrs)
{
- int r = swiotlb_map_sg_attrs(dev, sg, nents, dir, 0);
+ int r = swiotlb_map_sg_attrs(dev, sg, nents, dir, attrs);
mb();

return r;
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index b2eadd6..dd998d7 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -293,7 +293,7 @@ static inline void __dma_sync(struct page *page,
static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction direction, unsigned long attrs)
{
- if (cpu_needs_post_dma_flush(dev))
+ if (cpu_needs_post_dma_flush(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
__dma_sync(dma_addr_to_page(dev, dma_addr),
dma_addr & ~PAGE_MASK, size, direction);
plat_post_dma_flush(dev);
@@ -307,7 +307,8 @@ static int mips_dma_map_sg(struct device *dev, struct scatterlist *sglist,
struct scatterlist *sg;

for_each_sg(sglist, sg, nents, i) {
- if (!plat_device_is_coherent(dev))
+ if (!plat_device_is_coherent(dev) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
__dma_sync(sg_page(sg), sg->offset, sg->length,
direction);
#ifdef CONFIG_NEED_SG_DMA_LENGTH
@@ -324,7 +325,7 @@ static dma_addr_t mips_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction direction,
unsigned long attrs)
{
- if (!plat_device_is_coherent(dev))
+ if (!plat_device_is_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
__dma_sync(page, offset, size, direction);

return plat_map_dma_mem_page(dev, page) + offset;
@@ -339,6 +340,7 @@ static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,

for_each_sg(sglist, sg, nhwentries, i) {
if (!plat_device_is_coherent(dev) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
direction != DMA_TO_DEVICE)
__dma_sync(sg_page(sg), sg->offset, sg->length,
direction);
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