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 #include <asm/xen/swiotlb-xen.h>
  14 #include <asm/iommu_table.h>
  15 int swiotlb __read_mostly;
  16
  17 void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
  18                                         dma_addr_t *dma_handle, gfp_t flags,
  19                                         struct dma_attrs *attrs)
  20 {
  21         void *vaddr;
  22
  23         vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
  24                                            attrs);
  25         if (vaddr)
  26                 return vaddr;
  27
  28         return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  29 }
  30
  31 void x86_swiotlb_free_coherent(struct device *dev, size_t size,
  32                                       void *vaddr, dma_addr_t dma_addr,
  33                                       struct dma_attrs *attrs)
  34 {
  35         if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
  36                 swiotlb_free_coherent(dev, size, vaddr, dma_addr);
  37         else
  38                 dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
  39 }
  40
  41 static struct dma_map_ops swiotlb_dma_ops = {
  42         .mapping_error = swiotlb_dma_mapping_error,
  43         .alloc = x86_swiotlb_alloc_coherent,
  44         .free = x86_swiotlb_free_coherent,
  45         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  46         .sync_single_for_device = swiotlb_sync_single_for_device,
  47         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  48         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  49         .map_sg = swiotlb_map_sg_attrs,
  50         .unmap_sg = swiotlb_unmap_sg_attrs,
  51         .map_page = swiotlb_map_page,
  52         .unmap_page = swiotlb_unmap_page,
  53         .dma_supported = NULL,
  54 };
  55
  56 /*
  57  * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
  58  *
  59  * This returns non-zero if we are forced to use swiotlb (by the boot
  60  * option).
  61  */
  62 int __init pci_swiotlb_detect_override(void)
  63 {
  64         int use_swiotlb = swiotlb | swiotlb_force;
  65
  66         if (swiotlb_force)
  67                 swiotlb = 1;
  68
  69         return use_swiotlb;
  70 }
  71 IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
  72                   pci_xen_swiotlb_detect,
  73                   pci_swiotlb_init,
  74                   pci_swiotlb_late_init);
  75
  76 /*
  77  * if 4GB or more detected (and iommu=off not set) return 1
  78  * and set swiotlb to 1.
  79  */
  80 int __init pci_swiotlb_detect_4gb(void)
  81 {
  82         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
  83 #ifdef CONFIG_X86_64
  84         if (!no_iommu && max_pfn > MAX_DMA32_PFN)
  85                 swiotlb = 1;
  86 #endif
  87         return swiotlb;
  88 }
  89 IOMMU_INIT(pci_swiotlb_detect_4gb,
  90            pci_swiotlb_detect_override,
  91            pci_swiotlb_init,
  92            pci_swiotlb_late_init);
  93
  94 void __init pci_swiotlb_init(void)
  95 {
  96         if (swiotlb) {
  97                 swiotlb_init(0);
  98                 dma_ops = &swiotlb_dma_ops;
  99         }
 100 }
 101
 102 void __init pci_swiotlb_late_init(void)
 103 {
 104         /* An IOMMU turned us off. */
 105         if (!swiotlb)
 106                 swiotlb_free();
 107         else {
 108                 printk(KERN_INFO "PCI-DMA: "
 109                        "Using software bounce buffering for IO (SWIOTLB)\n");
 110                 swiotlb_print_info();
 111         }
 112 }