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Commit 2e332fec authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: dma: implement dma_unmap_page and sg variant 



Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent b37174d9

arch/arc/mm/dma.c

+45 −0
Original line number Diff line number Diff line
@@ -153,6 +153,19 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size, 
	}

}



/*

 * arc_dma_map_page - map a portion of a page for streaming DMA

 *

 * Ensure that any data held in the cache is appropriately discarded

 * or written back.

 *

 * The device owns this memory once this call has completed.  The CPU

 * can regain ownership by calling dma_unmap_page().

 *

 * Note: while it takes struct page as arg, caller can "abuse" it to pass

 * a region larger than PAGE_SIZE, provided it is physically contiguous

 * and this still works correctly

 */

static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,

		unsigned long offset, size_t size, enum dma_data_direction dir,

		unsigned long attrs)
@@ -165,6 +178,24 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page, 
	return plat_phys_to_dma(dev, paddr);

}



/*

 * arc_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()

 *

 * After this call, reads by the CPU to the buffer are guaranteed to see

 * whatever the device wrote there.

 *

 * Note: historically this routine was not implemented for ARC

 */

static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,

			       size_t size, enum dma_data_direction dir,

			       unsigned long attrs)

{

	phys_addr_t paddr = plat_dma_to_phys(dev, handle);



	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))

		_dma_cache_sync(paddr, size, dir);

}



static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,

	   int nents, enum dma_data_direction dir, unsigned long attrs)

{
@@ -178,6 +209,18 @@ static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg, 
	return nents;

}



static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,

			     int nents, enum dma_data_direction dir,

			     unsigned long attrs)

{

	struct scatterlist *s;

	int i;



	for_each_sg(sg, s, nents, i)

		arc_dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir,

				   attrs);

}



static void arc_dma_sync_single_for_cpu(struct device *dev,

		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)

{
@@ -223,7 +266,9 @@ const struct dma_map_ops arc_dma_ops = { 
	.free			= arc_dma_free,

	.mmap			= arc_dma_mmap,

	.map_page		= arc_dma_map_page,

	.unmap_page		= arc_dma_unmap_page,

	.map_sg			= arc_dma_map_sg,

	.unmap_sg		= arc_dma_unmap_sg,

	.sync_single_for_device	= arc_dma_sync_single_for_device,

	.sync_single_for_cpu	= arc_dma_sync_single_for_cpu,

	.sync_sg_for_cpu	= arc_dma_sync_sg_for_cpu,