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 <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 */
  18static 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
  26static 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 */
  37static 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
  47static 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
  56static 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
  64static 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 */
  73static 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
  93struct 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};
 102EXPORT_SYMBOL(dma_iommu_ops);
 103