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
  14 int swiotlb __read_mostly;
  15
  16 dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
  17 {
  18         return paddr;
  19 }
  20
  21 phys_addr_t swiotlb_bus_to_phys(struct device *hwdev, dma_addr_t baddr)
  22 {
  23         return baddr;
  24 }
  25
  26 int __weak swiotlb_arch_range_needs_mapping(phys_addr_t paddr, size_t size)
  27 {
  28         return 0;
  29 }
  30
  31 static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
  32                                         dma_addr_t *dma_handle, gfp_t flags)
  33 {
  34         void *vaddr;
  35
  36         vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
  37         if (vaddr)
  38                 return vaddr;
  39
  40         return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  41 }
  42
  43 static struct dma_map_ops swiotlb_dma_ops = {
  44         .mapping_error = swiotlb_dma_mapping_error,
  45         .alloc_coherent = x86_swiotlb_alloc_coherent,
  46         .free_coherent = swiotlb_free_coherent,
  47         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  48         .sync_single_for_device = swiotlb_sync_single_for_device,
  49         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
  50         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
  51         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  52         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  53         .map_sg = swiotlb_map_sg_attrs,
  54         .unmap_sg = swiotlb_unmap_sg_attrs,
  55         .map_page = swiotlb_map_page,
  56         .unmap_page = swiotlb_unmap_page,
  57         .dma_supported = NULL,
  58 };
  59
  60 void __init pci_swiotlb_init(void)
  61 {
  62         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
  63 #ifdef CONFIG_X86_64
  64         if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN) ||
  65                 iommu_pass_through)
  66                swiotlb = 1;
  67 #endif
  68         if (swiotlb_force)
  69                 swiotlb = 1;
  70         if (swiotlb) {
  71                 printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
  72                 swiotlb_init();
  73                 dma_ops = &swiotlb_dma_ops;
  74         }
  75 }