[PATCHv7 4/6] arm: dma-mapping: add {map, unmap}_resource for iommu ops

[Russell King - ARM Linux]

On Wed, Jun 01, 2016 at 05:22:27PM +0200, Niklas Söderlund wrote:
> +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);

Shouldn't both of these be unsigned - preferably size_t for len?

> +
> +	dma_addr = __alloc_iova(mapping, size);

Is this really correct?  What if size = 4095 and offset = 10?  Do we
really only need one IOVA page for such a mapping (I count two pages.)
Shouldn't this be "len" ?

> +	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);

Shouldn't this be "len" as well?

> +	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);

unsigned/size_t again.

> +
> +	if (!iova)
> +		return;
> +
> +	iommu_unmap(mapping->domain, iova, len);
> +	__free_iova(mapping, iova, len);

Here, you free "len" bytes of iova, which is different from above.

> +}
> +
>  static void arm_iommu_sync_single_for_cpu(struct device *dev,
>  		dma_addr_t handle, size_t size, enum dma_data_direction dir)
>  {
> @@ -1994,6 +2051,9 @@ struct dma_map_ops iommu_ops = {
>  	.unmap_sg		= arm_iommu_unmap_sg,
>  	.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,
>  };
>  
>  struct dma_map_ops iommu_coherent_ops = {
> @@ -2007,6 +2067,9 @@ 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,
>  };
>  
>  /**
> -- 
> 2.8.2
> 
> 
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