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Commit 13987d68 authored by Will Deacon's avatar Will Deacon Committed by Marek Szyprowski
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ARM: dma-mapping: convert DMA direction into IOMMU protection attributes 



IOMMU mappings take a prot parameter, identifying the protection bits
to enforce on the newly created mapping (READ or WRITE). The ARM
dma-mapping framework currently just passes 0 as the prot argument,
resulting in faulting mappings.

This patch infers the protection attributes based on the direction of
the DMA transfer.

Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
parent 836bfa0d

arch/arm/mm/dma-mapping.c

+16 −2
Original line number Diff line number Diff line
@@ -1637,13 +1637,27 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p 
{

	struct dma_iommu_mapping *mapping = dev->archdata.mapping;

	dma_addr_t dma_addr;

	int ret, len = PAGE_ALIGN(size + offset);

	int ret, prot, len = PAGE_ALIGN(size + offset);



	dma_addr = __alloc_iova(mapping, len);

	if (dma_addr == DMA_ERROR_CODE)

		return dma_addr;



	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);

	switch (dir) {

	case DMA_BIDIRECTIONAL:

		prot = IOMMU_READ | IOMMU_WRITE;

		break;

	case DMA_TO_DEVICE:

		prot = IOMMU_READ;

		break;

	case DMA_FROM_DEVICE:

		prot = IOMMU_WRITE;

		break;

	default:

		prot = 0;

	}



	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot);

	if (ret < 0)

		goto fail;