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