From 1d1ddf67dc3bfd80f60b216fa1fedfb242bee299 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Fri, 17 Jul 2015 16:58:21 +0100 Subject: [PATCH] arm64: dma-mapping: implement dma_get_sgtable() The default dma_common_get_sgtable() implementation relies on the CPU address of the buffer being a regular lowmem address. This is not always the case on arm64, since allocations from the various DMA pools may have remapped vmalloc addresses, rendering the use of virt_to_page() invalid. Fix this by providing our own implementation based on the fact that we can safely derive a physical address from the DMA address in both cases. CC: Jon Medhurst Signed-off-by: Robin Murphy [will: made static] Signed-off-by: Will Deacon --- arch/arm64/mm/dma-mapping.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 63b2a117a03c..e5d74cdfdb71 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -331,10 +331,24 @@ static int __swiotlb_mmap(struct device *dev, return ret; } +static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt, + void *cpu_addr, dma_addr_t handle, size_t size, + struct dma_attrs *attrs) +{ + int ret = sg_alloc_table(sgt, 1, GFP_KERNEL); + + if (!ret) + sg_set_page(sgt->sgl, phys_to_page(dma_to_phys(dev, handle)), + PAGE_ALIGN(size), 0); + + return ret; +} + static struct dma_map_ops swiotlb_dma_ops = { .alloc = __dma_alloc, .free = __dma_free, .mmap = __swiotlb_mmap, + .get_sgtable = __swiotlb_get_sgtable, .map_page = __swiotlb_map_page, .unmap_page = __swiotlb_unmap_page, .map_sg = __swiotlb_map_sg_attrs, -- 2.39.2