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Commit dc2832e1 authored by Marek Szyprowski's avatar Marek Szyprowski
Browse files

ARM: dma-mapping: add support for dma_get_sgtable() 



This patch adds support for dma_get_sgtable() function which is required
to let drivers to share the buffers allocated by DMA-mapping subsystem.

Generic implementation based on virt_to_page() is not suitable for ARM
dma-mapping subsystem.

Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
parent d2b7428e

arch/arm/common/dmabounce.c

+1 −0
Original line number Diff line number Diff line
@@ -452,6 +452,7 @@ static struct dma_map_ops dmabounce_ops = { 
	.alloc			= arm_dma_alloc,

	.free			= arm_dma_free,

	.mmap			= arm_dma_mmap,

	.get_sgtable		= arm_dma_get_sgtable,

	.map_page		= dmabounce_map_page,

	.unmap_page		= dmabounce_unmap_page,

	.sync_single_for_cpu	= dmabounce_sync_for_cpu,

arch/arm/include/asm/dma-mapping.h

+3 −0
Original line number Diff line number Diff line
@@ -261,6 +261,9 @@ extern void arm_dma_sync_sg_for_cpu(struct device *, struct scatterlist *, int, 
		enum dma_data_direction);

extern void arm_dma_sync_sg_for_device(struct device *, struct scatterlist *, int,

		enum dma_data_direction);

extern int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,

		void *cpu_addr, dma_addr_t dma_addr, size_t size,

		struct dma_attrs *attrs);



#endif /* __KERNEL__ */

#endif

arch/arm/mm/dma-mapping.c

+31 −0
Original line number Diff line number Diff line
@@ -125,6 +125,7 @@ struct dma_map_ops arm_dma_ops = { 
	.alloc			= arm_dma_alloc,

	.free			= arm_dma_free,

	.mmap			= arm_dma_mmap,

	.get_sgtable		= arm_dma_get_sgtable,

	.map_page		= arm_dma_map_page,

	.unmap_page		= arm_dma_unmap_page,

	.map_sg			= arm_dma_map_sg,
@@ -661,6 +662,21 @@ void arm_dma_free(struct device *dev, size_t size, void *cpu_addr, 
	}

}



int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,

		 void *cpu_addr, dma_addr_t handle, size_t size,

		 struct dma_attrs *attrs)

{

	struct page *page = pfn_to_page(dma_to_pfn(dev, handle));

	int ret;



	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);

	if (unlikely(ret))

		return ret;



	sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);

	return 0;

}



static void dma_cache_maint_page(struct page *page, unsigned long offset,

	size_t size, enum dma_data_direction dir,

	void (*op)(const void *, size_t, int))
@@ -1172,6 +1188,20 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, 
	__iommu_free_buffer(dev, pages, size);

}



static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,

				 void *cpu_addr, dma_addr_t dma_addr,

				 size_t size, struct dma_attrs *attrs)

{

	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;

	struct page **pages = __iommu_get_pages(cpu_addr, attrs);



	if (!pages)

		return -ENXIO;



	return sg_alloc_table_from_pages(sgt, pages, count, 0, size,

					 GFP_KERNEL);

}



/*

 * Map a part of the scatter-gather list into contiguous io address space

 */
@@ -1431,6 +1461,7 @@ struct dma_map_ops iommu_ops = { 
	.alloc		= arm_iommu_alloc_attrs,

	.free		= arm_iommu_free_attrs,

	.mmap		= arm_iommu_mmap_attrs,

	.get_sgtable	= arm_iommu_get_sgtable,



	.map_page		= arm_iommu_map_page,

	.unmap_page		= arm_iommu_unmap_page,