arch/ia64/kernel/pci-dma.c

   1 /*
   2  * Dynamic DMA mapping support.
   3  */
   4
   5 #include <linux/types.h>
   6 #include <linux/mm.h>
   7 #include <linux/string.h>
   8 #include <linux/pci.h>
   9 #include <linux/module.h>
  10 #include <linux/dmar.h>
  11 #include <asm/iommu.h>
  12 #include <asm/machvec.h>
  13 #include <linux/dma-mapping.h>
  14
  15 #include <asm/machvec.h>
  16 #include <asm/system.h>
  17
  18 #ifdef CONFIG_DMAR
  19
  20 #include <linux/kernel.h>
  21 #include <linux/string.h>
  22
  23 #include <asm/page.h>
  24 #include <asm/iommu.h>
  25
  26 dma_addr_t bad_dma_address __read_mostly;
  27 EXPORT_SYMBOL(bad_dma_address);
  28
  29 static int iommu_sac_force __read_mostly;
  30
  31 int no_iommu __read_mostly;
  32 #ifdef CONFIG_IOMMU_DEBUG
  33 int force_iommu __read_mostly = 1;
  34 #else
  35 int force_iommu __read_mostly;
  36 #endif
  37
  38 /* Set this to 1 if there is a HW IOMMU in the system */
  39 int iommu_detected __read_mostly;
  40
  41 /* Dummy device used for NULL arguments (normally ISA). Better would
  42    be probably a smaller DMA mask, but this is bug-to-bug compatible
  43    to i386. */
  44 struct device fallback_dev = {
  45         .bus_id = "fallback device",
  46         .coherent_dma_mask = DMA_32BIT_MASK,
  47         .dma_mask = &fallback_dev.coherent_dma_mask,
  48 };
  49
  50 void __init pci_iommu_alloc(void)
  51 {
  52         /*
  53          * The order of these functions is important for
  54          * fall-back/fail-over reasons
  55          */
  56         detect_intel_iommu();
  57
  58 #ifdef CONFIG_SWIOTLB
  59         pci_swiotlb_init();
  60 #endif
  61 }
  62
  63 static int __init pci_iommu_init(void)
  64 {
  65         if (iommu_detected)
  66                 intel_iommu_init();
  67
  68         return 0;
  69 }
  70
  71 /* Must execute after PCI subsystem */
  72 fs_initcall(pci_iommu_init);
  73
  74 void pci_iommu_shutdown(void)
  75 {
  76         return;
  77 }
  78
  79 void __init
  80 iommu_dma_init(void)
  81 {
  82         return;
  83 }
  84
  85 struct dma_mapping_ops *dma_ops;
  86 EXPORT_SYMBOL(dma_ops);
  87
  88 int iommu_dma_supported(struct device *dev, u64 mask)
  89 {
  90         struct dma_mapping_ops *ops = get_dma_ops(dev);
  91
  92         if (ops->dma_supported_op)
  93                 return ops->dma_supported_op(dev, mask);
  94
  95         /* Copied from i386. Doesn't make much sense, because it will
  96            only work for pci_alloc_coherent.
  97            The caller just has to use GFP_DMA in this case. */
  98         if (mask < DMA_24BIT_MASK)
  99                 return 0;
 100
 101         /* Tell the device to use SAC when IOMMU force is on.  This
 102            allows the driver to use cheaper accesses in some cases.
 103
 104            Problem with this is that if we overflow the IOMMU area and
 105            return DAC as fallback address the device may not handle it
 106            correctly.
 107
 108            As a special case some controllers have a 39bit address
 109            mode that is as efficient as 32bit (aic79xx). Don't force
 110            SAC for these.  Assume all masks <= 40 bits are of this
 111            type. Normally this doesn't make any difference, but gives
 112            more gentle handling of IOMMU overflow. */
 113         if (iommu_sac_force && (mask >= DMA_40BIT_MASK)) {
 114                 dev_info(dev, "Force SAC with mask %lx\n", mask);
 115                 return 0;
 116         }
 117
 118         return 1;
 119 }
 120 EXPORT_SYMBOL(iommu_dma_supported);
 121
 122 #endif