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Commit 9406a49f authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-mapping: support non-coherent devices in dma_common_get_sgtable 



We can use the arch_dma_coherent_to_pfn hook to provide a ->get_sgtable
implementation.  Note that this isn't an endorsement of this interface
(which is a horrible bad idea), but it is required to move arm64 over
to the generic code without a loss of functionality.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 58b04406

drivers/xen/swiotlb-xen.c

+1 −1
Original line number Diff line number Diff line
@@ -689,7 +689,7 @@ xen_swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt, 
							   handle, size, attrs);

	}

#endif

	return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size);

	return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size, attrs);

}



static int xen_swiotlb_mapping_error(struct device *dev, dma_addr_t dma_addr)

include/linux/dma-mapping.h

+4 −3
Original line number Diff line number Diff line
@@ -483,8 +483,8 @@ dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, 
#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0)



int

dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,

		       void *cpu_addr, dma_addr_t dma_addr, size_t size);

dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr,

		dma_addr_t dma_addr, size_t size, unsigned long attrs);



static inline int

dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
@@ -496,7 +496,8 @@ dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, 
	if (ops->get_sgtable)

		return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size,

					attrs);

	return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size);

	return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size,

			attrs);

}



#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0)

kernel/dma/mapping.c

+16 −7
Original line number Diff line number Diff line
@@ -202,17 +202,26 @@ EXPORT_SYMBOL(dmam_release_declared_memory); 
 * Create scatter-list for the already allocated DMA buffer.

 */

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

		 void *cpu_addr, dma_addr_t handle, size_t size)

		 void *cpu_addr, dma_addr_t dma_addr, size_t size,

		 unsigned long attrs)

{

	struct page *page = virt_to_page(cpu_addr);

	struct page *page;

	int ret;



	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);

	if (unlikely(ret))

		return ret;

	if (!dev_is_dma_coherent(dev)) {

		if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_COHERENT_TO_PFN))

			return -ENXIO;



		page = pfn_to_page(arch_dma_coherent_to_pfn(dev, cpu_addr,

				dma_addr));

	} else {

		page = virt_to_page(cpu_addr);

	}



	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);

	if (!ret)

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

	return 0;

	return ret;

}

EXPORT_SYMBOL(dma_common_get_sgtable);