2 * Dynamic DMA mapping support.
5 #include <linux/types.h>
7 #include <linux/string.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>
15 #include <asm/system.h>
19 #include <linux/kernel.h>
23 dma_addr_t bad_dma_address __read_mostly;
24 EXPORT_SYMBOL(bad_dma_address);
26 static int iommu_sac_force __read_mostly;
28 int no_iommu __read_mostly;
29 #ifdef CONFIG_IOMMU_DEBUG
30 int force_iommu __read_mostly = 1;
32 int force_iommu __read_mostly;
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
38 struct device fallback_dev = {
39 .init_name = "fallback device",
40 .coherent_dma_mask = DMA_BIT_MASK(32),
41 .dma_mask = &fallback_dev.coherent_dma_mask,
44 extern struct dma_map_ops intel_dma_ops;
46 static int __init pci_iommu_init(void)
54 /* Must execute after PCI subsystem */
55 fs_initcall(pci_iommu_init);
57 void pci_iommu_shutdown(void)
68 int iommu_dma_supported(struct device *dev, u64 mask)
70 struct dma_map_ops *ops = platform_dma_get_ops(dev);
72 if (ops->dma_supported)
73 return ops->dma_supported(dev, mask);
75 /* Copied from i386. Doesn't make much sense, because it will
76 only work for pci_alloc_coherent.
77 The caller just has to use GFP_DMA in this case. */
78 if (mask < DMA_24BIT_MASK)
81 /* Tell the device to use SAC when IOMMU force is on. This
82 allows the driver to use cheaper accesses in some cases.
84 Problem with this is that if we overflow the IOMMU area and
85 return DAC as fallback address the device may not handle it
88 As a special case some controllers have a 39bit address
89 mode that is as efficient as 32bit (aic79xx). Don't force
90 SAC for these. Assume all masks <= 40 bits are of this
91 type. Normally this doesn't make any difference, but gives
92 more gentle handling of IOMMU overflow. */
93 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
94 dev_info(dev, "Force SAC with mask %lx\n", mask);
100 EXPORT_SYMBOL(iommu_dma_supported);
102 void __init pci_iommu_alloc(void)
104 dma_ops = &intel_dma_ops;
106 dma_ops->sync_single_for_cpu = machvec_dma_sync_single;
107 dma_ops->sync_sg_for_cpu = machvec_dma_sync_sg;
108 dma_ops->sync_single_for_device = machvec_dma_sync_single;
109 dma_ops->sync_sg_for_device = machvec_dma_sync_sg;
110 dma_ops->dma_supported = iommu_dma_supported;
113 * The order of these functions is important for
114 * fall-back/fail-over reasons
116 detect_intel_iommu();
118 #ifdef CONFIG_SWIOTLB