[Linaro-mm-sig] [RFC 2/3] ARM: dma-mapping: Pass DMA attrs as IOMMU prot

Nishanth Peethambaran nishanth.p at gmail.com
Thu Jun 20 04:07:00 EDT 2013


Hi,

It would be better to define a prot flag bit in iommu API and convert
the attrs to prot flag bit in dma-mapping aPI before calling the iommu
API.

On Thu, Jun 20, 2013 at 11:19 AM, Hiroshi Doyu <hdoyu at nvidia.com> wrote:
>
> Pass DMA attribute as IOMMU property, which can be proccessed in the
> backend implementation of IOMMU. For example, DMA_ATTR_READ_ONLY can
> be translated into each IOMMU H/W implementaion.
>
> Signed-off-by: Hiroshi Doyu <hdoyu at nvidia.com>
> ---
>  arch/arm/mm/dma-mapping.c | 34 +++++++++++++++++++++-------------
>  1 file changed, 21 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 4152ed6..cbc6768 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1254,7 +1254,8 @@ err:
>   */
>  static dma_addr_t
>  ____iommu_create_mapping(struct device *dev, dma_addr_t *req,
> -                        struct page **pages, size_t size)
> +                        struct page **pages, size_t size,
> +                        struct dma_attrs *attrs)
>  {
>         struct dma_iommu_mapping *mapping = dev->archdata.mapping;
>         unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> @@ -1280,7 +1281,7 @@ ____iommu_create_mapping(struct device *dev, dma_addr_t *req,
>                                 break;
>
>                 len = (j - i) << PAGE_SHIFT;
> -               ret = iommu_map(mapping->domain, iova, phys, len, 0);
> +               ret = iommu_map(mapping->domain, iova, phys, len, (int)attrs);

Use dma_get_attr and translate the READ_ONLY attr to a new READ_ONLY
prot flag bit which needs to be defined in iommu.h

>                 if (ret < 0)
>                         goto fail;
>                 iova += len;
> @@ -1294,9 +1295,10 @@ fail:
>  }
>
>  static dma_addr_t
> -__iommu_create_mapping(struct device *dev, struct page **pages, size_t size)
> +__iommu_create_mapping(struct device *dev, struct page **pages, size_t size,
> +                      struct dma_attrs *attrs)
>  {
> -       return ____iommu_create_mapping(dev, NULL, pages, size);
> +       return ____iommu_create_mapping(dev, NULL, pages, size, attrs);
>  }
>
>  static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t size)
> @@ -1332,7 +1334,7 @@ static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs *attrs)
>  }
>
>  static void *__iommu_alloc_atomic(struct device *dev, size_t size,
> -                                 dma_addr_t *handle)
> +                                 dma_addr_t *handle, struct dma_attrs *attrs)
>  {
>         struct page *page;
>         void *addr;
> @@ -1341,7 +1343,7 @@ static void *__iommu_alloc_atomic(struct device *dev, size_t size,
>         if (!addr)
>                 return NULL;
>
> -       *handle = __iommu_create_mapping(dev, &page, size);
> +       *handle = __iommu_create_mapping(dev, &page, size, attrs);
>         if (*handle == DMA_ERROR_CODE)
>                 goto err_mapping;
>
> @@ -1378,17 +1380,20 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
>         size = PAGE_ALIGN(size);
>
>         if (gfp & GFP_ATOMIC)
> -               return __iommu_alloc_atomic(dev, size, handle);
> +
> +               return __iommu_alloc_atomic(dev, size, handle, attrs);
>
>         pages = __iommu_alloc_buffer(dev, size, gfp);
>         if (!pages)
>                 return NULL;
>
>         if (*handle == DMA_ERROR_CODE)
> -               *handle = __iommu_create_mapping(dev, pages, size);
> +               *handle = __iommu_create_mapping(dev, pages, size, attrs);
>         else
> -               *handle = ____iommu_create_mapping(dev, handle, pages, size);
> +               *handle = ____iommu_create_mapping(dev, handle, pages, size,
> +                                                  attrs);
>
> +       *handle = __iommu_create_mapping(dev, pages, size, attrs);
>         if (*handle == DMA_ERROR_CODE)
>                 goto err_buffer;
>
> @@ -1513,7 +1518,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
>
>  skip_cmaint:
>         count = size >> PAGE_SHIFT;
> -       ret = iommu_map_sg(mapping->domain, iova_base, sg, count, 0);
> +       ret = iommu_map_sg(mapping->domain, iova_base, sg, count, (int)attrs);

Use dma_get_attr and translate the READ_ONLY attr to a new READ_ONLY
prot flag bit which needs to be defined in iommu.h

>         if (WARN_ON(ret < 0))
>                 goto fail;
>
> @@ -1716,7 +1721,8 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p
>         if (dma_addr == DMA_ERROR_CODE)
>                 return dma_addr;
>
> -       ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
> +       ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len,
> +                       (int)attrs);

Use dma_get_attr and translate the READ_ONLY attr to a new READ_ONLY
prot flag bit which needs to be defined in iommu.h

>         if (ret < 0)
>                 goto fail;
>
> @@ -1756,7 +1762,8 @@ static dma_addr_t arm_iommu_map_page_at(struct device *dev, struct page *page,
>         if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
>                 __dma_page_cpu_to_dev(page, offset, size, dir);
>
> -       ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
> +       ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len,
> +                       (int)attrs);

Use dma_get_attr and translate the READ_ONLY attr to a new READ_ONLY
prot flag bit which needs to be defined in iommu.h

>         if (ret < 0)
>                 return DMA_ERROR_CODE;
>
> @@ -1778,7 +1785,8 @@ static dma_addr_t arm_iommu_map_pages(struct device *dev, struct page **pages,
>                         __dma_page_cpu_to_dev(pages[i], 0, PAGE_SIZE, dir);
>         }
>
> -       ret = iommu_map_pages(mapping->domain, dma_handle, pages, count, 0);
> +       ret = iommu_map_pages(mapping->domain, dma_handle, pages, count,
> +                             (int)attrs);

Use dma_get_attr and translate the READ_ONLY attr to a new READ_ONLY
prot flag bit which needs to be defined in iommu.h

>         if (ret < 0)
>                 return DMA_ERROR_CODE;
>
> --
> 1.8.1.5
>
>
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