[PATCH 1/1] ARM: dma-mapping: Allow DMA_NONE to skip cache_maint

[Hiroshi DOYU]

Signed-off-by: Hiroshi DOYU <hdoyu@xxxxxxxxxx>
---
 arch/arm/mm/dma-mapping.c                |   16 ++++++++--------
 drivers/video/tegra/nvmap/nvmap.c        |    2 +-
 drivers/video/tegra/nvmap/nvmap_handle.c |    2 +-
 include/linux/dma-mapping.h              |   16 +++++++++++++---
 4 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 83f0ac6..c4b1587 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1161,7 +1161,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
 		phys_addr_t phys = page_to_phys(sg_page(s));
 		unsigned int len = PAGE_ALIGN(s->offset + s->length);
 
-		if (!arch_is_coherent())
+		if (!arch_is_coherent() && (dir != DMA_NONE))
 			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
 
 		ret = iommu_map(mapping->domain, iova, phys, len, 0);
@@ -1254,7 +1254,7 @@ void arm_iommu_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 		if (sg_dma_len(s))
 			__iommu_remove_mapping(dev, sg_dma_address(s),
 					       sg_dma_len(s));
-		if (!arch_is_coherent())
+		if (!arch_is_coherent() && (dir != DMA_NONE))
 			__dma_page_dev_to_cpu(sg_page(s), s->offset,
 					      s->length, dir);
 	}
@@ -1274,7 +1274,7 @@ void arm_iommu_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, s, nents, i)
-		if (!arch_is_coherent())
+		if (!arch_is_coherent() && (dir != DMA_NONE))
 			__dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir);
 
 }
@@ -1293,7 +1293,7 @@ void arm_iommu_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, s, nents, i)
-		if (!arch_is_coherent())
+		if (!arch_is_coherent() && (dir != DMA_NONE))
 			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
 }
 
@@ -1305,7 +1305,7 @@ static dma_addr_t __arm_iommu_map_page_at(struct device *dev, struct page *page,
 	dma_addr_t dma_addr;
 	int ret, len = PAGE_ALIGN(size + offset);
 
-	if (!arch_is_coherent())
+	if (!arch_is_coherent() && (dir != DMA_NONE))
 		__dma_page_cpu_to_dev(page, offset, size, dir);
 
 	dma_addr = __alloc_iova_at(mapping, req, len);
@@ -1349,7 +1349,7 @@ dma_addr_t arm_iommu_map_page_at(struct device *dev, struct page *page,
 	unsigned int phys;
 	int ret;
 
-	if (!arch_is_coherent())
+	if (!arch_is_coherent() && (dir != DMA_NONE))
 		__dma_page_cpu_to_dev(page, offset, size, dir);
 
 	/* Check if iova area is reserved in advance. */
@@ -1386,7 +1386,7 @@ static void __arm_iommu_unmap_page_at(struct device *dev, dma_addr_t handle,
 	if (!iova)
 		return;
 
-	if (!arch_is_coherent())
+	if (!arch_is_coherent() && (dir != DMA_NONE))
 		__dma_page_dev_to_cpu(page, offset, size, dir);
 
 	iommu_unmap(mapping->domain, iova, len);
@@ -1430,7 +1430,7 @@ static void arm_iommu_sync_single_for_cpu(struct device *dev,
 	if (!iova)
 		return;
 
-	if (!arch_is_coherent())
+	if (!arch_is_coherent() && (dir != DMA_NONE))
 		__dma_page_dev_to_cpu(page, offset, size, dir);
 }
 
diff --git a/drivers/video/tegra/nvmap/nvmap.c b/drivers/video/tegra/nvmap/nvmap.c
index 1032224..e98dd11 100644
--- a/drivers/video/tegra/nvmap/nvmap.c
+++ b/drivers/video/tegra/nvmap/nvmap.c
@@ -56,7 +56,7 @@ static void map_iovmm_area(struct nvmap_handle *h)
 		BUG_ON(!pfn_valid(page_to_pfn(h->pgalloc.pages[i])));
 
 		iova = dma_map_page_at(to_iovmm_dev(h), h->pgalloc.pages[i],
-				       va, 0, PAGE_SIZE, DMA_BIDIRECTIONAL);
+				       va, 0, PAGE_SIZE, DMA_NONE);
 		BUG_ON(iova != va);
 	}
 	h->pgalloc.dirty = false;
diff --git a/drivers/video/tegra/nvmap/nvmap_handle.c b/drivers/video/tegra/nvmap/nvmap_handle.c
index 853f87e..b2bbeb1 100644
--- a/drivers/video/tegra/nvmap/nvmap_handle.c
+++ b/drivers/video/tegra/nvmap/nvmap_handle.c
@@ -504,7 +504,7 @@ void nvmap_free_vm(struct device *dev, struct tegra_iovmm_area *area)
 		dma_addr_t iova;
 
 		iova = area->iovm_start + i * PAGE_SIZE;
-		dma_unmap_page(dev, iova, PAGE_SIZE, DMA_BIDIRECTIONAL);
+		dma_unmap_page(dev, iova, PAGE_SIZE, DMA_NONE);
 	}
 	kfree(area);
 }
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 36dfe06..cbd8d47 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -55,9 +55,19 @@ struct dma_map_ops {
 
 static inline int valid_dma_direction(int dma_direction)
 {
-	return ((dma_direction == DMA_BIDIRECTIONAL) ||
-		(dma_direction == DMA_TO_DEVICE) ||
-		(dma_direction == DMA_FROM_DEVICE));
+	int ret = 1;
+
+	switch (dma_direction) {
+	case DMA_BIDIRECTIONAL:
+	case DMA_TO_DEVICE:
+	case DMA_FROM_DEVICE:
+	case DMA_NONE:
+		break;
+	default:
+		ret = !!ret;
+		break;
+	} 
+	return ret;
 }
 
 static inline int is_device_dma_capable(struct device *dev)
-- 
1.7.5.4

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