1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Dynamic DMA mapping support. 4 */ 5 6 #include <linux/types.h> 7 #include <linux/mm.h> 8 #include <linux/string.h> 9 #include <linux/pci.h> 10 #include <linux/module.h> 11 #include <linux/dmar.h> 12 #include <asm/iommu.h> 13 #include <asm/machvec.h> 14 #include <linux/dma-mapping.h> 15 #include <linux/kernel.h> 16 #include <asm/page.h> 17 18 dma_addr_t bad_dma_address __read_mostly; 19 EXPORT_SYMBOL(bad_dma_address); 20 21 static int iommu_sac_force __read_mostly; 22 23 int no_iommu __read_mostly; 24 #ifdef CONFIG_IOMMU_DEBUG 25 int force_iommu __read_mostly = 1; 26 #else 27 int force_iommu __read_mostly; 28 #endif 29 30 int iommu_pass_through; 31 32 extern struct dma_map_ops intel_dma_ops; 33 34 static int __init pci_iommu_init(void) 35 { 36 if (iommu_detected) 37 intel_iommu_init(); 38 39 return 0; 40 } 41 42 /* Must execute after PCI subsystem */ 43 fs_initcall(pci_iommu_init); 44 45 void pci_iommu_shutdown(void) 46 { 47 return; 48 } 49 50 void __init 51 iommu_dma_init(void) 52 { 53 return; 54 } 55 56 int iommu_dma_supported(struct device *dev, u64 mask) 57 { 58 /* Copied from i386. Doesn't make much sense, because it will 59 only work for pci_alloc_coherent. 60 The caller just has to use GFP_DMA in this case. */ 61 if (mask < DMA_BIT_MASK(24)) 62 return 0; 63 64 /* Tell the device to use SAC when IOMMU force is on. This 65 allows the driver to use cheaper accesses in some cases. 66 67 Problem with this is that if we overflow the IOMMU area and 68 return DAC as fallback address the device may not handle it 69 correctly. 70 71 As a special case some controllers have a 39bit address 72 mode that is as efficient as 32bit (aic79xx). Don't force 73 SAC for these. Assume all masks <= 40 bits are of this 74 type. Normally this doesn't make any difference, but gives 75 more gentle handling of IOMMU overflow. */ 76 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) { 77 dev_info(dev, "Force SAC with mask %llx\n", mask); 78 return 0; 79 } 80 81 return 1; 82 } 83 EXPORT_SYMBOL(iommu_dma_supported); 84 85 void __init pci_iommu_alloc(void) 86 { 87 dma_ops = &intel_dma_ops; 88 89 intel_dma_ops.sync_single_for_cpu = machvec_dma_sync_single; 90 intel_dma_ops.sync_sg_for_cpu = machvec_dma_sync_sg; 91 intel_dma_ops.sync_single_for_device = machvec_dma_sync_single; 92 intel_dma_ops.sync_sg_for_device = machvec_dma_sync_sg; 93 intel_dma_ops.dma_supported = iommu_dma_supported; 94 95 /* 96 * The order of these functions is important for 97 * fall-back/fail-over reasons 98 */ 99 detect_intel_iommu(); 100 101 #ifdef CONFIG_SWIOTLB 102 if (!iommu_detected) { 103 #ifdef CONFIG_IA64_GENERIC 104 printk(KERN_INFO "PCI-DMA: Re-initialize machine vector.\n"); 105 machvec_init("dig"); 106 swiotlb_dma_init(); 107 #else 108 panic("Unable to find Intel IOMMU"); 109 #endif /* CONFIG_IA64_GENERIC */ 110 } 111 #endif /* CONFIG_SWIOTLB */ 112 } 113