LXR linux/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>
  15int swiotlb __read_mostly;
  16
  17void *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        /*
  24         * Don't print a warning when the first allocation attempt fails.
  25         * swiotlb_alloc_coherent() will print a warning when the DMA
  26         * memory allocation ultimately failed.
  27         */
  28        flags |= __GFP_NOWARN;
  29
  30        vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
  31                                           attrs);
  32        if (vaddr)
  33                return vaddr;
  34
  35        return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
  36}
  37
  38void x86_swiotlb_free_coherent(struct device *dev, size_t size,
  39                                      void *vaddr, dma_addr_t dma_addr,
  40                                      struct dma_attrs *attrs)
  41{
  42        if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
  43                swiotlb_free_coherent(dev, size, vaddr, dma_addr);
  44        else
  45                dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
  46}
  47
  48static struct dma_map_ops swiotlb_dma_ops = {
  49        .mapping_error = swiotlb_dma_mapping_error,
  50        .alloc = x86_swiotlb_alloc_coherent,
  51        .free = x86_swiotlb_free_coherent,
  52        .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  53        .sync_single_for_device = swiotlb_sync_single_for_device,
  54        .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  55        .sync_sg_for_device = swiotlb_sync_sg_for_device,
  56        .map_sg = swiotlb_map_sg_attrs,
  57        .unmap_sg = swiotlb_unmap_sg_attrs,
  58        .map_page = swiotlb_map_page,
  59        .unmap_page = swiotlb_unmap_page,
  60        .dma_supported = NULL,
  61};
  62
  63/*
  64 * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
  65 *
  66 * This returns non-zero if we are forced to use swiotlb (by the boot
  67 * option).
  68 */
  69int __init pci_swiotlb_detect_override(void)
  70{
  71        int use_swiotlb = swiotlb | swiotlb_force;
  72
  73        if (swiotlb_force)
  74                swiotlb = 1;
  75
  76        return use_swiotlb;
  77}
  78IOMMU_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) return 1
  85 * and set swiotlb to 1.
  86 */
  87int __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_pfn > MAX_DMA32_PFN)
  92                swiotlb = 1;
  93#endif
  94        return swiotlb;
  95}
  96IOMMU_INIT(pci_swiotlb_detect_4gb,
  97           pci_swiotlb_detect_override,
  98           pci_swiotlb_init,
  99           pci_swiotlb_late_init);
 100
 101void __init pci_swiotlb_init(void)
 102{
 103        if (swiotlb) {
 104                swiotlb_init(0);
 105                dma_ops = &swiotlb_dma_ops;
 106        }
 107}
 108
 109void __init pci_swiotlb_late_init(void)
 110{
 111        /* An IOMMU turned us off. */
 112        if (!swiotlb)
 113                swiotlb_free();
 114        else {
 115                printk(KERN_INFO "PCI-DMA: "
 116                       "Using software bounce buffering for IO (SWIOTLB)\n");
 117                swiotlb_print_info();
 118        }
 119}
 120