LXR linux/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 */
  19static 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
  27static 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 */
  38static 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
  48static 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
  57static 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
  65static 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 */
  74static 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
  94static 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
 107struct 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};
 117EXPORT_SYMBOL(dma_iommu_ops);
 118