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arm64: dma-mapping: implement dma_get_sgtable()

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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 <tixy@linaro.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[will: made static]
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Robin Murphy 2015-07-17 16:58:21 +01:00 committed by Will Deacon
parent 4b3dc9679c
commit 1d1ddf67dc
1 changed files with 14 additions and 0 deletions
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14
arch/arm64/mm/dma-mapping.c
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@ -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,