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SubjectRe: [PATCH v3 4/8] arm: dma-mapping: add {map,unmap}_resource for iommu ops
Date
Hi Niklas,

Thank you for the patch.

On Wednesday 10 February 2016 01:57:54 Niklas Söderlund wrote:
> Add methods to map/unmap device resources addresses for dma_map_ops that
> are IOMMU aware. This is needed to map a device MMIO register from a
> physical address.
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> arch/arm/mm/dma-mapping.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 63 insertions(+)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 0eca381..ae2b175 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1814,6 +1814,63 @@ static void arm_iommu_unmap_page(struct device *dev,
> dma_addr_t handle, __free_iova(mapping, iova, len);
> }
>
> +/**
> + * arm_iommu_map_resource - map a device resource for DMA
> + * @dev: valid struct device pointer
> + * @phys_addr: physical address of resource
> + * @size: size of resource to map
> + * @dir: DMA transfer direction
> + */
> +static dma_addr_t arm_iommu_map_resource(struct device *dev,
> + phys_addr_t phys_addr, size_t size,
> + enum dma_data_direction dir, struct dma_attrs *attrs)
> +{
> + struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
> + dma_addr_t dma_addr;
> + int ret, prot;
> + phys_addr_t addr = phys_addr & PAGE_MASK;
> + int offset = phys_addr & ~PAGE_MASK;
> + int len = PAGE_ALIGN(size + offset);
> +
> + dma_addr = __alloc_iova(mapping, size);
> + if (dma_addr == DMA_ERROR_CODE)
> + return dma_addr;
> +
> + prot = __dma_direction_to_prot(dir) | IOMMU_MMIO;
> +
> + ret = iommu_map(mapping->domain, dma_addr, addr, len, prot);
> + if (ret < 0)
> + goto fail;
> +
> + return dma_addr + offset;
> +fail:
> + __free_iova(mapping, dma_addr, size);
> + return DMA_ERROR_CODE;
> +}
> +
> +/**
> + * arm_iommu_unmap_resource - unmap a device DMA resource
> + * @dev: valid struct device pointer
> + * @dma_handle: DMA address to resource
> + * @size: size of resource to map
> + * @dir: DMA transfer direction
> + */
> +static void arm_iommu_unmap_resource(struct device *dev, dma_addr_t
> dma_handle, + size_t size, enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
> + dma_addr_t iova = dma_handle & PAGE_MASK;
> + int offset = dma_handle & ~PAGE_MASK;
> + int len = PAGE_ALIGN(size + offset);
> +
> + if (!iova)
> + return;
> +
> + iommu_unmap(mapping->domain, iova, len);
> + __free_iova(mapping, iova, len);
> +}
> +
> static void arm_iommu_sync_single_for_cpu(struct device *dev,
> dma_addr_t handle, size_t size, enum dma_data_direction dir)
> {
> @@ -1858,6 +1915,9 @@ struct dma_map_ops iommu_ops = {
> .sync_sg_for_cpu = arm_iommu_sync_sg_for_cpu,
> .sync_sg_for_device = arm_iommu_sync_sg_for_device,
>
> + .map_resource = arm_iommu_map_resource,
> + .unmap_resource = arm_iommu_unmap_resource,
> +
> .set_dma_mask = arm_dma_set_mask,
> };
>
> @@ -1873,6 +1933,9 @@ struct dma_map_ops iommu_coherent_ops = {
> .map_sg = arm_coherent_iommu_map_sg,
> .unmap_sg = arm_coherent_iommu_unmap_sg,
>
> + .map_resource = arm_iommu_map_resource,
> + .unmap_resource = arm_iommu_unmap_resource,
> +
> .set_dma_mask = arm_dma_set_mask,
> };

--
Regards,

Laurent Pinchart

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