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 123