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Commit 251533eb authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

swiotlb: add common swiotlb_map_ops 



Currently all architectures that want to use swiotlb have to implement
their own dma_map_ops instances.  Provide a generic one based on the
x86 implementation which first calls into dma_direct to try a full blown
direct mapping implementation (including e.g. CMA) before falling back
allocating from the swiotlb buffer.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
parent 7f2c8bbd

include/linux/swiotlb.h

+8 −0
Original line number Diff line number Diff line
@@ -66,6 +66,12 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev, 
				    enum dma_sync_target target);



/* Accessory functions. */



void *swiotlb_alloc(struct device *hwdev, size_t size, dma_addr_t *dma_handle,

		gfp_t flags, unsigned long attrs);

void swiotlb_free(struct device *dev, size_t size, void *vaddr,

		dma_addr_t dma_addr, unsigned long attrs);



extern void

*swiotlb_alloc_coherent(struct device *hwdev, size_t size,

			dma_addr_t *dma_handle, gfp_t flags);
@@ -126,4 +132,6 @@ extern void swiotlb_print_info(void); 
extern int is_swiotlb_buffer(phys_addr_t paddr);

extern void swiotlb_set_max_segment(unsigned int);



extern const struct dma_map_ops swiotlb_dma_ops;



#endif /* __LINUX_SWIOTLB_H */

lib/swiotlb.c

+43 −0
Original line number Diff line number Diff line
@@ -1087,3 +1087,46 @@ swiotlb_dma_supported(struct device *hwdev, u64 mask) 
	return swiotlb_phys_to_dma(hwdev, io_tlb_end - 1) <= mask;

}

EXPORT_SYMBOL(swiotlb_dma_supported);



#ifdef CONFIG_DMA_DIRECT_OPS

void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,

		gfp_t gfp, unsigned long attrs)

{

	void *vaddr;



	/*

	 * Don't print a warning when the first allocation attempt fails.

	 * swiotlb_alloc_coherent() will print a warning when the DMA memory

	 * allocation ultimately failed.

	 */

	gfp |= __GFP_NOWARN;



	vaddr = dma_direct_alloc(dev, size, dma_handle, gfp, attrs);

	if (!vaddr)

		vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, gfp);

	return vaddr;

}



void swiotlb_free(struct device *dev, size_t size, void *vaddr,

		dma_addr_t dma_addr, unsigned long attrs)

{

	if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))

		swiotlb_free_coherent(dev, size, vaddr, dma_addr);

	else

		dma_direct_free(dev, size, vaddr, dma_addr, attrs);

}



const struct dma_map_ops swiotlb_dma_ops = {

	.mapping_error		= swiotlb_dma_mapping_error,

	.alloc			= swiotlb_alloc,

	.free			= swiotlb_free,

	.sync_single_for_cpu	= swiotlb_sync_single_for_cpu,

	.sync_single_for_device	= swiotlb_sync_single_for_device,

	.sync_sg_for_cpu	= swiotlb_sync_sg_for_cpu,

	.sync_sg_for_device	= swiotlb_sync_sg_for_device,

	.map_sg			= swiotlb_map_sg_attrs,

	.unmap_sg		= swiotlb_unmap_sg_attrs,

	.map_page		= swiotlb_map_page,

	.unmap_page		= swiotlb_unmap_page,

};

#endif /* CONFIG_DMA_DIRECT_OPS */