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 <linux/export.h>
   9 #include <asm/iommu.h>
  10
  11 /*
  12  * Generic iommu implementation
  13  */
  14
  15 /* Allocates a contiguous real buffer and creates mappings over it.
  16  * Returns the virtual address of the buffer and sets dma_handle
  17  * to the dma address (mapping) of the first page.
  18  */
  19 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
  20                                       dma_addr_t *dma_handle, gfp_t flag)
  21 {
  22         return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
  23                                     dma_handle, dev->coherent_dma_mask, flag,
  24                                     dev_to_node(dev));
  25 }
  26
  27 static void dma_iommu_free_coherent(struct device *dev, size_t size,
  28                                     void *vaddr, dma_addr_t dma_handle)
  29 {
  30         iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
  31 }
  32
  33 /* Creates TCEs for a user provided buffer.  The user buffer must be
  34  * contiguous real kernel storage (not vmalloc).  The address passed here
  35  * comprises a page address and offset into that page. The dma_addr_t
  36  * returned will point to the same byte within the page as was passed in.
  37  */
  38 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
  39                                      unsigned long offset, size_t size,
  40                                      enum dma_data_direction direction,
  41                                      struct dma_attrs *attrs)
  42 {
  43         return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
  44                               size, device_to_mask(dev), direction, attrs);
  45 }
  46
  47
  48 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
  49                                  size_t size, enum dma_data_direction direction,
  50                                  struct dma_attrs *attrs)
  51 {
  52         iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
  53                          attrs);
  54 }
  55
  56
  57 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
  58                             int nelems, enum dma_data_direction direction,
  59                             struct dma_attrs *attrs)
  60 {
  61         return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
  62                             device_to_mask(dev), direction, attrs);
  63 }
  64
  65 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
  66                 int nelems, enum dma_data_direction direction,
  67                 struct dma_attrs *attrs)
  68 {
  69         iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
  70                        attrs);
  71 }
  72
  73 /* We support DMA to/from any memory page via the iommu */
  74 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
  75 {
  76         struct iommu_table *tbl = get_iommu_table_base(dev);
  77
  78         if (!tbl) {
  79                 dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
  80                         ", table unavailable\n", mask);
  81                 return 0;
  82         }
  83
  84         if ((tbl->it_offset + tbl->it_size) > (mask >> IOMMU_PAGE_SHIFT)) {
  85                 dev_info(dev, "Warning: IOMMU window too big for device mask\n");
  86                 dev_info(dev, "mask: 0x%08llx, table end: 0x%08lx\n",
  87                                 mask, (tbl->it_offset + tbl->it_size) <<
  88                                 IOMMU_PAGE_SHIFT);
  89                 return 0;
  90         } else
  91                 return 1;
  92 }
  93
  94 static u64 dma_iommu_get_required_mask(struct device *dev)
  95 {
  96         struct iommu_table *tbl = get_iommu_table_base(dev);
  97         u64 mask;
  98         if (!tbl)
  99                 return 0;
 100
 101         mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
 102         mask += mask - 1;
 103
 104         return mask;
 105 }
 106
 107 struct dma_map_ops dma_iommu_ops = {
 108         .alloc_coherent         = dma_iommu_alloc_coherent,
 109         .free_coherent          = dma_iommu_free_coherent,
 110         .map_sg                 = dma_iommu_map_sg,
 111         .unmap_sg               = dma_iommu_unmap_sg,
 112         .dma_supported          = dma_iommu_dma_supported,
 113         .map_page               = dma_iommu_map_page,
 114         .unmap_page             = dma_iommu_unmap_page,
 115         .get_required_mask      = dma_iommu_get_required_mask,
 116 };
 117 EXPORT_SYMBOL(dma_iommu_ops);