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Commit a1831bb9 authored by Robin Murphy's avatar Robin Murphy Committed by Joerg Roedel
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iommu/dma: Remove bogus dma_supported() implementation 



Back when this was first written, dma_supported() was somewhat of a
murky mess, with subtly different interpretations being relied upon in
various places. The "does device X support DMA to address range Y?"
uses assuming Y to be physical addresses, which motivated the current
iommu_dma_supported() implementation and are alluded to in the comment
therein, have since been cleaned up, leaving only the far less ambiguous
"can device X drive address bits Y" usage internal to DMA API mask
setting. As such, there is no reason to keep a slightly misleading
callback which does nothing but duplicate the current default behaviour;
we already constrain IOVA allocations to the iommu_domain aperture where
necessary, so let's leave DMA mask business to architecture-specific
code where it belongs.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 122fac03

arch/arm64/mm/dma-mapping.c

+0 −1
Original line number Diff line number Diff line
@@ -799,7 +799,6 @@ static struct dma_map_ops iommu_dma_ops = { 
	.sync_sg_for_device = __iommu_sync_sg_for_device,

	.map_resource = iommu_dma_map_resource,

	.unmap_resource = iommu_dma_unmap_resource,

	.dma_supported = iommu_dma_supported,

	.mapping_error = iommu_dma_mapping_error,

};

drivers/iommu/dma-iommu.c

+0 −10
Original line number Diff line number Diff line
@@ -734,16 +734,6 @@ void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle, 
	__iommu_dma_unmap(iommu_get_domain_for_dev(dev), handle);

}



int iommu_dma_supported(struct device *dev, u64 mask)

{

	/*

	 * 'Special' IOMMUs which don't have the same addressing capability

	 * as the CPU will have to wait until we have some way to query that

	 * before they'll be able to use this framework.

	 */

	return 1;

}



int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)

{

	return dma_addr == DMA_ERROR_CODE;

include/linux/dma-iommu.h

+0 −1
Original line number Diff line number Diff line
@@ -67,7 +67,6 @@ dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys, 
		size_t size, enum dma_data_direction dir, unsigned long attrs);

void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,

		size_t size, enum dma_data_direction dir, unsigned long attrs);

int iommu_dma_supported(struct device *dev, u64 mask);

int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);



/* The DMA API isn't _quite_ the whole story, though... */