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Commit e5cc8650 authored by Charan Teja Reddy's avatar Charan Teja Reddy
Browse files

arm: mm: call __iommu_map_sg for unaligned buffers 



For unaligned offset/size buffers given in the sg list from the client,
call the __iommu_map_sg which properly handles it.
Also support the per-buffer coherency in __iommu_map_sg.

Change-Id: I0c617465e005d4c25c1c54ba784e2082d9afcefb
Signed-off-by: default avatarCharan Teja Reddy <charante@codeaurora.org>
parent 75654f2c

arch/arm/mm/dma-mapping.c

+34 −3
Original line number Diff line number Diff line
@@ -1862,7 +1862,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, 
	int ret = 0;

	unsigned int count;

	struct scatterlist *s;

	int prot;

	int prot = 0;



	size = PAGE_ALIGN(size);

	*handle = DMA_ERROR_CODE;
@@ -1871,6 +1871,11 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, 
	if (iova == DMA_ERROR_CODE)

		return -ENOMEM;



	/*

	 * Check for coherency.

	 */

	prot |= is_coherent ? IOMMU_CACHE : 0;



	for (count = 0, s = sg; count < (size >> PAGE_SHIFT); s = sg_next(s)) {

		phys_addr_t phys = page_to_phys(sg_page(s));

		unsigned int len = PAGE_ALIGN(s->offset + s->length);
@@ -1878,7 +1883,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, 
		if (!is_coherent && (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)

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



		prot = __dma_direction_to_prot(dir);

		prot |= __dma_direction_to_prot(dir);



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

		if (ret < 0)
@@ -1982,9 +1987,35 @@ int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg, 
	dma_addr_t iova;

	bool coherent;

	int prot = __dma_direction_to_prot(dir);

	int upstream_hint = 0;

	/*

	 * This is used to check if there are any unaligned offset/size

	 * given in the scatter list.

	 */

	bool unaligned_offset_size = false;



	for_each_sg(sg, s, nents, i)

	for_each_sg(sg, s, nents, i) {

		total_length += s->length;

		if ((s->offset & ~PAGE_MASK) || (s->length & ~PAGE_MASK)) {

			unaligned_offset_size = true;

			break;

		}

	}



	/*

	 * Check for the upstream domain attribute just to catch

	 * any abusive clients who expects the unaligned offset/size

	 * support with out setting this attribute.

	 * NOTE: on future kernels, we may not have this domain

	 * attribute set where the check then will be based on just

	 * offset/size.

	 */

	iommu_domain_get_attr(mapping->domain,

			      DOMAIN_ATTR_UPSTREAM_IOVA_ALLOCATOR,

			      &upstream_hint);

	if (upstream_hint && unaligned_offset_size)

		return __iommu_map_sg(dev, sg, nents, dir, attrs,

				      is_dma_coherent(dev, attrs, false));



	iova = __alloc_iova(mapping, total_length);

	if (iova == DMA_ERROR_CODE)