arch/x86/kernel/pci-swiotlb_64.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 void *swiotlb_alloc_boot(size_t size, unsigned long nslabs)
  17 {
  18         return alloc_bootmem_low_pages(size);
  19 }
  20
  21 void *swiotlb_alloc(unsigned order, unsigned long nslabs)
  22 {
  23         return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
  24 }
  25
  26 dma_addr_t swiotlb_phys_to_bus(phys_addr_t paddr)
  27 {
  28         return paddr;
  29 }
  30
  31 phys_addr_t swiotlb_bus_to_phys(dma_addr_t baddr)
  32 {
  33         return baddr;
  34 }
  35
  36 int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
  37 {
  38         return 0;
  39 }
  40
  41 static dma_addr_t
  42 swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
  43                         int direction)
  44 {
  45         return swiotlb_map_single(hwdev, phys_to_virt(paddr), size, direction);
  46 }
  47
  48 static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
  49                                         dma_addr_t *dma_handle, gfp_t flags)
  50 {
  51         void *vaddr;
  52
  53         vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
  54         if (vaddr)
  55                 return vaddr;
  56
  57         return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  58 }
  59
  60 struct dma_mapping_ops swiotlb_dma_ops = {
  61         .mapping_error = swiotlb_dma_mapping_error,
  62         .alloc_coherent = x86_swiotlb_alloc_coherent,
  63         .free_coherent = swiotlb_free_coherent,
  64         .map_single = swiotlb_map_single_phys,
  65         .unmap_single = swiotlb_unmap_single,
  66         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  67         .sync_single_for_device = swiotlb_sync_single_for_device,
  68         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
  69         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
  70         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  71         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  72         .map_sg = swiotlb_map_sg,
  73         .unmap_sg = swiotlb_unmap_sg,
  74         .dma_supported = NULL,
  75 };
  76
  77 void __init pci_swiotlb_init(void)
  78 {
  79         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
  80 #ifdef CONFIG_X86_64
  81         if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
  82                swiotlb = 1;
  83 #endif
  84         if (swiotlb_force)
  85                 swiotlb = 1;
  86         if (swiotlb) {
  87                 printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
  88                 swiotlb_init();
  89                 dma_ops = &swiotlb_dma_ops;
  90         }
  91 }