arch/powerpc/kernel/dma-iommu.c

   1 /*
   2  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   3  *
   4  * Provide default implementations of the DMA mapping callbacks for
   5  * busses using the iommu infrastructure
   6  */
   7
   8 #include <asm/iommu.h>
   9
  10 /*
  11  * Generic iommu implementation
  12  */
  13
  14 /* Allocates a contiguous real buffer and creates mappings over it.
  15  * Returns the virtual address of the buffer and sets dma_handle
  16  * to the dma address (mapping) of the first page.
  17  */
  18 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
  19                                       dma_addr_t *dma_handle, gfp_t flag)
  20 {
  21         return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
  22                                     dma_handle, dev->coherent_dma_mask, flag,
  23                                     dev_to_node(dev));
  24 }
  25
  26 static void dma_iommu_free_coherent(struct device *dev, size_t size,
  27                                     void *vaddr, dma_addr_t dma_handle)
  28 {
  29         iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
  30 }
  31
  32 /* Creates TCEs for a user provided buffer.  The user buffer must be
  33  * contiguous real kernel storage (not vmalloc).  The address passed here
  34  * comprises a page address and offset into that page. The dma_addr_t
  35  * returned will point to the same byte within the page as was passed in.
  36  */
  37 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
  38                                      unsigned long offset, size_t size,
  39                                      enum dma_data_direction direction,
  40                                      struct dma_attrs *attrs)
  41 {
  42         return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
  43                               size, device_to_mask(dev), direction, attrs);
  44 }
  45
  46
  47 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
  48                                  size_t size, enum dma_data_direction direction,
  49                                  struct dma_attrs *attrs)
  50 {
  51         iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
  52                          attrs);
  53 }
  54
  55
  56 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
  57                             int nelems, enum dma_data_direction direction,
  58                             struct dma_attrs *attrs)
  59 {
  60         return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
  61                             device_to_mask(dev), direction, attrs);
  62 }
  63
  64 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
  65                 int nelems, enum dma_data_direction direction,
  66                 struct dma_attrs *attrs)
  67 {
  68         iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
  69                        attrs);
  70 }
  71
  72 /* We support DMA to/from any memory page via the iommu */
  73 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
  74 {
  75         struct iommu_table *tbl = get_iommu_table_base(dev);
  76
  77         if (!tbl) {
  78                 dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
  79                         ", table unavailable\n", mask);
  80                 return 0;
  81         }
  82
  83         if ((tbl->it_offset + tbl->it_size) > (mask >> IOMMU_PAGE_SHIFT)) {
  84                 dev_info(dev, "Warning: IOMMU window too big for device mask\n");
  85                 dev_info(dev, "mask: 0x%08llx, table end: 0x%08lx\n",
  86                                 mask, (tbl->it_offset + tbl->it_size) <<
  87                                 IOMMU_PAGE_SHIFT);
  88                 return 0;
  89         } else
  90                 return 1;
  91 }
  92
  93 struct dma_map_ops dma_iommu_ops = {
  94         .alloc_coherent = dma_iommu_alloc_coherent,
  95         .free_coherent  = dma_iommu_free_coherent,
  96         .map_sg         = dma_iommu_map_sg,
  97         .unmap_sg       = dma_iommu_unmap_sg,
  98         .dma_supported  = dma_iommu_dma_supported,
  99         .map_page       = dma_iommu_map_page,
 100         .unmap_page     = dma_iommu_unmap_page,
 101 };
 102 EXPORT_SYMBOL(dma_iommu_ops);