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/init.h>
   6 #include <linux/swiotlb.h>
   7 #include <linux/bootmem.h>
   8 #include <linux/dma-mapping.h>
   9 #include <linux/mem_encrypt.h>
  10
  11 #include <asm/iommu.h>
  12 #include <asm/swiotlb.h>
  13 #include <asm/dma.h>
  14 #include <asm/xen/swiotlb-xen.h>
  15 #include <asm/iommu_table.h>
  16
  17 int swiotlb __read_mostly;
  18
  19 void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
  20                                         dma_addr_t *dma_handle, gfp_t flags,
  21                                         unsigned long attrs)
  22 {
  23         void *vaddr;
  24
  25         /*
  26          * Don't print a warning when the first allocation attempt fails.
  27          * swiotlb_alloc_coherent() will print a warning when the DMA
  28          * memory allocation ultimately failed.
  29          */
  30         flags |= __GFP_NOWARN;
  31
  32         vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
  33                                            attrs);
  34         if (vaddr)
  35                 return vaddr;
  36
  37         return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  38 }
  39
  40 void x86_swiotlb_free_coherent(struct device *dev, size_t size,
  41                                       void *vaddr, dma_addr_t dma_addr,
  42                                       unsigned long attrs)
  43 {
  44         if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
  45                 swiotlb_free_coherent(dev, size, vaddr, dma_addr);
  46         else
  47                 dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
  48 }
  49
  50 static const struct dma_map_ops swiotlb_dma_ops = {
  51         .mapping_error = swiotlb_dma_mapping_error,
  52         .alloc = x86_swiotlb_alloc_coherent,
  53         .free = x86_swiotlb_free_coherent,
  54         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  55         .sync_single_for_device = swiotlb_sync_single_for_device,
  56         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  57         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  58         .map_sg = swiotlb_map_sg_attrs,
  59         .unmap_sg = swiotlb_unmap_sg_attrs,
  60         .map_page = swiotlb_map_page,
  61         .unmap_page = swiotlb_unmap_page,
  62         .dma_supported = NULL,
  63 };
  64
  65 /*
  66  * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
  67  *
  68  * This returns non-zero if we are forced to use swiotlb (by the boot
  69  * option).
  70  */
  71 int __init pci_swiotlb_detect_override(void)
  72 {
  73         if (swiotlb_force == SWIOTLB_FORCE)
  74                 swiotlb = 1;
  75
  76         return swiotlb;
  77 }
  78 IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
  79                   pci_xen_swiotlb_detect,
  80                   pci_swiotlb_init,
  81                   pci_swiotlb_late_init);
  82
  83 /*
  84  * If 4GB or more detected (and iommu=off not set) or if SME is active
  85  * then set swiotlb to 1 and return 1.
  86  */
  87 int __init pci_swiotlb_detect_4gb(void)
  88 {
  89         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
  90 #ifdef CONFIG_X86_64
  91         if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
  92                 swiotlb = 1;
  93 #endif
  94
  95         /*
  96          * If SME is active then swiotlb will be set to 1 so that bounce
  97          * buffers are allocated and used for devices that do not support
  98          * the addressing range required for the encryption mask.
  99          */
 100         if (sme_active())
 101                 swiotlb = 1;
 102
 103         return swiotlb;
 104 }
 105 IOMMU_INIT(pci_swiotlb_detect_4gb,
 106            pci_swiotlb_detect_override,
 107            pci_swiotlb_init,
 108            pci_swiotlb_late_init);
 109
 110 void __init pci_swiotlb_init(void)
 111 {
 112         if (swiotlb) {
 113                 swiotlb_init(0);
 114                 dma_ops = &swiotlb_dma_ops;
 115         }
 116 }
 117
 118 void __init pci_swiotlb_late_init(void)
 119 {
 120         /* An IOMMU turned us off. */
 121         if (!swiotlb)
 122                 swiotlb_free();
 123         else {
 124                 printk(KERN_INFO "PCI-DMA: "
 125                        "Using software bounce buffering for IO (SWIOTLB)\n");
 126                 swiotlb_print_info();
 127         }
 128 }