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Commit f28fc293 authored by Laura Abbott's avatar Laura Abbott
Browse files

arm64: Use custom mmap function for noncoherent dma ops 



The non-coherent dma ops remap memory with appropriate attributes.
This remapped address cannot be used with virt_to_page which
dma_common_mmap uses. Implement a custom (but very similar) function
which correctly calculates the physical address and remaps to userspace.

Change-Id: I3a85670d38b9c098af27a366c8421a616d6c815d
Signed-off-by: default avatarLaura Abbott <lauraa@codeaurora.org>
parent 500bff85

arch/arm64/mm/dma-mapping.c

+29 −0
Original line number Diff line number Diff line
@@ -237,9 +237,38 @@ static void arm64_swiotlb_sync_sg_for_device(struct device *dev, 
			       sg->length, dir);

}



int arm64_swiotlb_mmap(struct device *dev, struct vm_area_struct *vma,

		 void *cpu_addr, dma_addr_t dma_addr, size_t size,

		 struct dma_attrs *attrs)

{

	int ret = -ENXIO;

	unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >>

					PAGE_SHIFT;

	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;

	unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT;

	unsigned long off = vma->vm_pgoff;



	vma->vm_page_prot = __get_dma_pgprot(vma->vm_page_prot, attrs);



	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))

		return ret;



	if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {

		ret = remap_pfn_range(vma, vma->vm_start,

				      pfn + off,

				      vma->vm_end - vma->vm_start,

				      vma->vm_page_prot);

	}



	return ret;

}







struct dma_map_ops noncoherent_swiotlb_dma_ops = {

	.alloc = arm64_swiotlb_alloc_noncoherent,

	.free = arm64_swiotlb_free_noncoherent,

	.mmap = arm64_swiotlb_mmap,

	.map_page = arm64_swiotlb_map_page,

	.unmap_page = arm64_swiotlb_unmap_page,

	.map_sg = arm64_swiotlb_map_sg_attrs,