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Subject[net-next PATCH 15/27] arch/nios2: 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: Ley Foon Tan <lftan@altera.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
arch/nios2/mm/dma-mapping.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/arch/nios2/mm/dma-mapping.c b/arch/nios2/mm/dma-mapping.c
index d800fad..f6a5dcf 100644
--- a/arch/nios2/mm/dma-mapping.c
+++ b/arch/nios2/mm/dma-mapping.c
@@ -98,13 +98,17 @@ static int nios2_dma_map_sg(struct device *dev, struct scatterlist *sg,
int i;

for_each_sg(sg, sg, nents, i) {
- void *addr;
+ void *addr = sg_virt(sg);

- addr = sg_virt(sg);
- if (addr) {
- __dma_sync_for_device(addr, sg->length, direction);
- sg->dma_address = sg_phys(sg);
- }
+ if (!addr)
+ continue;
+
+ sg->dma_address = sg_phys(sg);
+
+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ continue;
+
+ __dma_sync_for_device(addr, sg->length, direction);
}

return nents;
@@ -117,7 +121,9 @@ static dma_addr_t nios2_dma_map_page(struct device *dev, struct page *page,
{
void *addr = page_address(page) + offset;

- __dma_sync_for_device(addr, size, direction);
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ __dma_sync_for_device(addr, size, direction);
+
return page_to_phys(page) + offset;
}

@@ -125,7 +131,8 @@ static void nios2_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
size_t size, enum dma_data_direction direction,
unsigned long attrs)
{
- __dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ __dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
}

static void nios2_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
@@ -138,6 +145,9 @@ static void nios2_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
if (direction == DMA_TO_DEVICE)
return;

+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ return;
+
for_each_sg(sg, sg, nhwentries, i) {
addr = sg_virt(sg);
if (addr)
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