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 = get_dma_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 117