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 static dma_addr_t
  37 swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
  38                         int direction)
  39 {
  40         return swiotlb_map_single(hwdev, phys_to_virt(paddr), size, direction);
  41 }
  42
  43 static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
  44                                         dma_addr_t *dma_handle, gfp_t flags)
  45 {
  46         void *vaddr;
  47
  48         vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
  49         if (vaddr)
  50                 return vaddr;
  51
  52         return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  53 }
  54
  55 struct dma_mapping_ops swiotlb_dma_ops = {
  56         .mapping_error = swiotlb_dma_mapping_error,
  57         .alloc_coherent = x86_swiotlb_alloc_coherent,
  58         .free_coherent = swiotlb_free_coherent,
  59         .map_single = swiotlb_map_single_phys,
  60         .unmap_single = swiotlb_unmap_single,
  61         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  62         .sync_single_for_device = swiotlb_sync_single_for_device,
  63         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
  64         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
  65         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  66         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  67         .map_sg = swiotlb_map_sg,
  68         .unmap_sg = swiotlb_unmap_sg,
  69         .dma_supported = NULL,
  70 };
  71
  72 void __init pci_swiotlb_init(void)
  73 {
  74         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
  75 #ifdef CONFIG_X86_64
  76         if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
  77                swiotlb = 1;
  78 #endif
  79         if (swiotlb_force)
  80                 swiotlb = 1;
  81         if (swiotlb) {
  82                 printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
  83                 swiotlb_init();
  84                 dma_ops = &swiotlb_dma_ops;
  85         }
  86 }