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