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

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@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@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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