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
  17static 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
  31static 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
  38static 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 */
  59int __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}
  68IOMMU_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 */
  77int __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}
  86IOMMU_INIT(pci_swiotlb_detect_4gb,
  87           pci_swiotlb_detect_override,
  88           pci_swiotlb_init,
  89           pci_swiotlb_late_init);
  90
  91void __init pci_swiotlb_init(void)
  92{
  93        if (swiotlb) {
  94                swiotlb_init(0);
  95                dma_ops = &swiotlb_dma_ops;
  96        }
  97}
  98
  99void __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}
 110