Commit 2e12dcee authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Konrad Rzeszutek Wilk
Browse files

swiotlb-xen: simplify the DMA sync method implementations 



Get rid of the grand multiplexer and implement the sync_single_for_cpu
and sync_single_for_device methods directly, and then loop over them
for the scatterlist based variants.

Note that this also loses a few comments related to highlevel DMA API
concepts, which have nothing to do with the swiotlb-xen implementation
details.

Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 8b35d9fe

drivers/xen/swiotlb-xen.c

+28 −56
Original line number Diff line number Diff line
@@ -452,48 +452,28 @@ static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, 
	xen_unmap_single(hwdev, dev_addr, size, dir, attrs);

}



/*

 * Make physical memory consistent for a single streaming mode DMA translation

 * after a transfer.

 *

 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer

 * using the cpu, yet do not wish to teardown the dma mapping, you must

 * call this function before doing so.  At the next point you give the dma

 * address back to the card, you must first perform a

 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer

 */

static void

xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,

			size_t size, enum dma_data_direction dir,

			enum dma_sync_target target)

xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,

		size_t size, enum dma_data_direction dir)

{

	phys_addr_t paddr = xen_bus_to_phys(dev_addr);



	BUG_ON(dir == DMA_NONE);

	phys_addr_t paddr = xen_bus_to_phys(dma_addr);



	if (target == SYNC_FOR_CPU)

		xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir);

	xen_dma_sync_single_for_cpu(dev, dma_addr, size, dir);



	/* NOTE: We use dev_addr here, not paddr! */

	if (is_xen_swiotlb_buffer(dev_addr))

		swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);



	if (target == SYNC_FOR_DEVICE)

		xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir);

	if (is_xen_swiotlb_buffer(dma_addr))

		swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);

}



void

xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,

static void

xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,

		size_t size, enum dma_data_direction dir)

{

	xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);

}

	phys_addr_t paddr = xen_bus_to_phys(dma_addr);



void

xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,

				   size_t size, enum dma_data_direction dir)

{

	xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);

	if (is_xen_swiotlb_buffer(dma_addr))

		swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);



	xen_dma_sync_single_for_device(dev, dma_addr, size, dir);

}



/*
@@ -538,38 +518,30 @@ out_unmap: 
	return 0;

}



/*

 * Make physical memory consistent for a set of streaming mode DMA translations

 * after a transfer.

 *

 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules

 * and usage.

 */

static void

xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,

		    int nelems, enum dma_data_direction dir,

		    enum dma_sync_target target)

xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,

			    int nelems, enum dma_data_direction dir)

{

	struct scatterlist *sg;

	int i;



	for_each_sg(sgl, sg, nelems, i)

		xen_swiotlb_sync_single(hwdev, sg->dma_address,

					sg_dma_len(sg), dir, target);

	for_each_sg(sgl, sg, nelems, i) {

		xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,

				sg->length, dir);

	}



static void

xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,

			    int nelems, enum dma_data_direction dir)

{

	xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);

}



static void

xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,

xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,

			       int nelems, enum dma_data_direction dir)

{

	xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);

	struct scatterlist *sg;

	int i;



	for_each_sg(sgl, sg, nelems, i) {

		xen_swiotlb_sync_single_for_device(dev, sg->dma_address,

				sg->length, dir);

	}

}



/*

CRA Git | Maintained and supported by SUSTech CRA and CCSE