Commit 18c9cbb0 authored by Leon Romanovsky's avatar Leon Romanovsky Committed by Marek Szyprowski
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dma-mapping: implement DMA_ATTR_MMIO for dma_(un)map_page_attrs() 



Make dma_map_page_attrs() and dma_map_page_attrs() respect
DMA_ATTR_MMIO.

DMA_ATR_MMIO makes the functions behave the same as
dma_(un)map_resource():
 - No swiotlb is possible
 - Legacy dma_ops arches use ops->map_resource()
 - No kmsan
 - No arch_dma_map_phys_direct()

The prior patches have made the internal functions called here
support DMA_ATTR_MMIO.

This is also preparation for turning dma_map_resource() into an inline
calling dma_map_phys(DMA_ATTR_MMIO) to consolidate the flows.

Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/3660e2c78ea409d6c483a215858fb3af52cd0ed3.1757423202.git.leonro@nvidia.com
parent 6eb1e769

kernel/dma/mapping.c

+21 −5
Original line number Diff line number Diff line
@@ -158,6 +158,7 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, 
{

	const struct dma_map_ops *ops = get_dma_ops(dev);

	phys_addr_t phys = page_to_phys(page) + offset;

	bool is_mmio = attrs & DMA_ATTR_MMIO;

	dma_addr_t addr;



	BUG_ON(!valid_dma_direction(dir));
@@ -166,13 +167,24 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, 
		return DMA_MAPPING_ERROR;



	if (dma_map_direct(dev, ops) ||

	    arch_dma_map_phys_direct(dev, phys + size))

	    (!is_mmio && arch_dma_map_phys_direct(dev, phys + size)))

		addr = dma_direct_map_phys(dev, phys, size, dir, attrs);

	else if (use_dma_iommu(dev))

		addr = iommu_dma_map_phys(dev, phys, size, dir, attrs);

	else

	else if (is_mmio) {

		if (!ops->map_resource)

			return DMA_MAPPING_ERROR;



		addr = ops->map_resource(dev, phys, size, dir, attrs);

	} else {

		/*

		 * The dma_ops API contract for ops->map_page() requires

		 * kmappable memory, while ops->map_resource() does not.

		 */

		addr = ops->map_page(dev, page, offset, size, dir, attrs);

	}



	if (!is_mmio)

		kmsan_handle_dma(phys, size, dir);

	trace_dma_map_phys(dev, phys, addr, size, dir, attrs);

	debug_dma_map_phys(dev, phys, size, dir, addr, attrs);
@@ -185,14 +197,18 @@ void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size, 
		enum dma_data_direction dir, unsigned long attrs)

{

	const struct dma_map_ops *ops = get_dma_ops(dev);

	bool is_mmio = attrs & DMA_ATTR_MMIO;



	BUG_ON(!valid_dma_direction(dir));

	if (dma_map_direct(dev, ops) ||

	    arch_dma_unmap_phys_direct(dev, addr + size))

	    (!is_mmio && arch_dma_unmap_phys_direct(dev, addr + size)))

		dma_direct_unmap_phys(dev, addr, size, dir, attrs);

	else if (use_dma_iommu(dev))

		iommu_dma_unmap_phys(dev, addr, size, dir, attrs);

	else

	else if (is_mmio) {

		if (ops->unmap_resource)

			ops->unmap_resource(dev, addr, size, dir, attrs);

	} else

		ops->unmap_page(dev, addr, size, dir, attrs);

	trace_dma_unmap_phys(dev, addr, size, dir, attrs);

	debug_dma_unmap_phys(dev, addr, size, dir);