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kernel/linux-imx6_3.14.28/arch/powerpc/kernel/dma-iommu.c 3.54 KB
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  /*
   * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   *
   * Provide default implementations of the DMA mapping callbacks for
   * busses using the iommu infrastructure
   */
  
  #include <linux/export.h>
  #include <asm/iommu.h>
  
  /*
   * Generic iommu implementation
   */
  
  /* Allocates a contiguous real buffer and creates mappings over it.
   * Returns the virtual address of the buffer and sets dma_handle
   * to the dma address (mapping) of the first page.
   */
  static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
  				      dma_addr_t *dma_handle, gfp_t flag,
  				      struct dma_attrs *attrs)
  {
  	return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
  				    dma_handle, dev->coherent_dma_mask, flag,
  				    dev_to_node(dev));
  }
  
  static void dma_iommu_free_coherent(struct device *dev, size_t size,
  				    void *vaddr, dma_addr_t dma_handle,
  				    struct dma_attrs *attrs)
  {
  	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
  }
  
  /* Creates TCEs for a user provided buffer.  The user buffer must be
   * contiguous real kernel storage (not vmalloc).  The address passed here
   * comprises a page address and offset into that page. The dma_addr_t
   * returned will point to the same byte within the page as was passed in.
   */
  static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
  				     unsigned long offset, size_t size,
  				     enum dma_data_direction direction,
  				     struct dma_attrs *attrs)
  {
  	return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
  			      size, device_to_mask(dev), direction, attrs);
  }
  
  
  static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
  				 size_t size, enum dma_data_direction direction,
  				 struct dma_attrs *attrs)
  {
  	iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
  			 attrs);
  }
  
  
  static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
  			    int nelems, enum dma_data_direction direction,
  			    struct dma_attrs *attrs)
  {
  	return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
  			    device_to_mask(dev), direction, attrs);
  }
  
  static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
  		int nelems, enum dma_data_direction direction,
  		struct dma_attrs *attrs)
  {
  	iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
  		       attrs);
  }
  
  /* We support DMA to/from any memory page via the iommu */
  static int dma_iommu_dma_supported(struct device *dev, u64 mask)
  {
  	struct iommu_table *tbl = get_iommu_table_base(dev);
  
  	if (!tbl) {
  		dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
  			", table unavailable
  ", mask);
  		return 0;
  	}
  
  	if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
  		dev_info(dev, "Warning: IOMMU offset too big for device mask
  ");
  		dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx
  ",
  				mask, tbl->it_offset << tbl->it_page_shift);
  		return 0;
  	} else
  		return 1;
  }
  
  static u64 dma_iommu_get_required_mask(struct device *dev)
  {
  	struct iommu_table *tbl = get_iommu_table_base(dev);
  	u64 mask;
  	if (!tbl)
  		return 0;
  
  	mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
  	mask += mask - 1;
  
  	return mask;
  }
  
  struct dma_map_ops dma_iommu_ops = {
  	.alloc			= dma_iommu_alloc_coherent,
  	.free			= dma_iommu_free_coherent,
  	.mmap			= dma_direct_mmap_coherent,
  	.map_sg			= dma_iommu_map_sg,
  	.unmap_sg		= dma_iommu_unmap_sg,
  	.dma_supported		= dma_iommu_dma_supported,
  	.map_page		= dma_iommu_map_page,
  	.unmap_page		= dma_iommu_unmap_page,
  	.get_required_mask	= dma_iommu_get_required_mask,
  };
  EXPORT_SYMBOL(dma_iommu_ops);