Commit c9b24996 authored by Andreas Herrmann's avatar Andreas Herrmann Committed by Marek Szyprowski
Browse files

ARM: dma-mapping: Always pass proper prot flags to iommu_map() 



... otherwise it is impossible for the low level iommu driver to
figure out which pte flags should be used.

In __map_sg_chunk we can derive the flags from dma_data_direction.

In __iommu_create_mapping we should treat the memory like
DMA_BIDIRECTIONAL and pass both IOMMU_READ and IOMMU_WRITE to
iommu_map.
__iommu_create_mapping is used during dma_alloc_coherent (via
arm_iommu_alloc_attrs).  AFAIK dma_alloc_coherent is responsible for
allocation _and_ mapping.  I think this implies that access to the
mapped pages should be allowed.

Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarAndreas Herrmann <andreas.herrmann@calxeda.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
parent 15c03dd4

arch/arm/mm/dma-mapping.c

+28 −15
Original line number Diff line number Diff line
@@ -1232,7 +1232,8 @@ __iommu_create_mapping(struct device *dev, struct page **pages, size_t size) 
				break;



		len = (j - i) << PAGE_SHIFT;

		ret = iommu_map(mapping->domain, iova, phys, len, 0);

		ret = iommu_map(mapping->domain, iova, phys, len,

				IOMMU_READ|IOMMU_WRITE);

		if (ret < 0)

			goto fail;

		iova += len;
@@ -1431,6 +1432,27 @@ static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt, 
					 GFP_KERNEL);

}



static int __dma_direction_to_prot(enum dma_data_direction dir)

{

	int prot;



	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;

	}



	return prot;

}



/*

 * Map a part of the scatter-gather list into contiguous io address space

 */
@@ -1444,6 +1466,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, 
	int ret = 0;

	unsigned int count;

	struct scatterlist *s;

	int prot;



	size = PAGE_ALIGN(size);

	*handle = DMA_ERROR_CODE;
@@ -1460,7 +1483,9 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, 
			!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))

			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);



		ret = iommu_map(mapping->domain, iova, phys, len, 0);

		prot = __dma_direction_to_prot(dir);



		ret = iommu_map(mapping->domain, iova, phys, len, prot);

		if (ret < 0)

			goto fail;

		count += len >> PAGE_SHIFT;
@@ -1665,19 +1690,7 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p 
	if (dma_addr == DMA_ERROR_CODE)

		return dma_addr;



	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;

	}

	prot = __dma_direction_to_prot(dir);



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

	if (ret < 0)

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