LXR linux/arch/x86/kernel/pci-swiotlb.c

   1/* Glue code to lib/swiotlb.c */
   2
   3#include <linux/pci.h>
   4#include <linux/cache.h>
   5#include <linux/module.h>
   6#include <linux/swiotlb.h>
   7#include <linux/bootmem.h>
   8#include <linux/dma-mapping.h>
   9
  10#include <asm/iommu.h>
  11#include <asm/swiotlb.h>
  12#include <asm/dma.h>
  13
  14int swiotlb __read_mostly;
  15
  16static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
  17                                        dma_addr_t *dma_handle, gfp_t flags)
  18{
  19        void *vaddr;
  20
  21        vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
  22        if (vaddr)
  23                return vaddr;
  24
  25        return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  26}
  27
  28static struct dma_map_ops swiotlb_dma_ops = {
  29        .mapping_error = swiotlb_dma_mapping_error,
  30        .alloc_coherent = x86_swiotlb_alloc_coherent,
  31        .free_coherent = swiotlb_free_coherent,
  32        .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  33        .sync_single_for_device = swiotlb_sync_single_for_device,
  34        .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
  35        .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
  36        .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  37        .sync_sg_for_device = swiotlb_sync_sg_for_device,
  38        .map_sg = swiotlb_map_sg_attrs,
  39        .unmap_sg = swiotlb_unmap_sg_attrs,
  40        .map_page = swiotlb_map_page,
  41        .unmap_page = swiotlb_unmap_page,
  42        .dma_supported = NULL,
  43};
  44
  45void __init pci_swiotlb_init(void)
  46{
  47        /* don't initialize swiotlb if iommu=off (no_iommu=1) */
  48#ifdef CONFIG_X86_64
  49        if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN))
  50                swiotlb = 1;
  51#endif
  52        if (swiotlb_force)
  53                swiotlb = 1;
  54        if (swiotlb) {
  55                printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
  56                swiotlb_init();
  57                dma_ops = &swiotlb_dma_ops;
  58        }
  59}
  60