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