1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation 4 * 5 * Provide default implementations of the DMA mapping callbacks for 6 * busses using the iommu infrastructure 7 */ 8 9 #include <linux/dma-direct.h> 10 #include <linux/pci.h> 11 #include <asm/iommu.h> 12 13 #ifdef CONFIG_ARCH_HAS_DMA_MAP_DIRECT 14 #define can_map_direct(dev, addr) \ 15 ((dev)->bus_dma_limit >= phys_to_dma((dev), (addr))) 16 17 bool arch_dma_map_page_direct(struct device *dev, phys_addr_t addr) 18 { 19 if (likely(!dev->bus_dma_limit)) 20 return false; 21 22 return can_map_direct(dev, addr); 23 } 24 25 #define is_direct_handle(dev, h) ((h) >= (dev)->archdata.dma_offset) 26 27 bool arch_dma_unmap_page_direct(struct device *dev, dma_addr_t dma_handle) 28 { 29 if (likely(!dev->bus_dma_limit)) 30 return false; 31 32 return is_direct_handle(dev, dma_handle); 33 } 34 35 bool arch_dma_map_sg_direct(struct device *dev, struct scatterlist *sg, 36 int nents) 37 { 38 struct scatterlist *s; 39 int i; 40 41 if (likely(!dev->bus_dma_limit)) 42 return false; 43 44 for_each_sg(sg, s, nents, i) { 45 if (!can_map_direct(dev, sg_phys(s) + s->offset + s->length)) 46 return false; 47 } 48 49 return true; 50 } 51 52 bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg, 53 int nents) 54 { 55 struct scatterlist *s; 56 int i; 57 58 if (likely(!dev->bus_dma_limit)) 59 return false; 60 61 for_each_sg(sg, s, nents, i) { 62 if (!is_direct_handle(dev, s->dma_address + s->length)) 63 return false; 64 } 65 66 return true; 67 } 68 #endif /* CONFIG_ARCH_HAS_DMA_MAP_DIRECT */ 69 70 /* 71 * Generic iommu implementation 72 */ 73 74 /* Allocates a contiguous real buffer and creates mappings over it. 75 * Returns the virtual address of the buffer and sets dma_handle 76 * to the dma address (mapping) of the first page. 77 */ 78 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size, 79 dma_addr_t *dma_handle, gfp_t flag, 80 unsigned long attrs) 81 { 82 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size, 83 dma_handle, dev->coherent_dma_mask, flag, 84 dev_to_node(dev)); 85 } 86 87 static void dma_iommu_free_coherent(struct device *dev, size_t size, 88 void *vaddr, dma_addr_t dma_handle, 89 unsigned long attrs) 90 { 91 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle); 92 } 93 94 /* Creates TCEs for a user provided buffer. The user buffer must be 95 * contiguous real kernel storage (not vmalloc). The address passed here 96 * comprises a page address and offset into that page. The dma_addr_t 97 * returned will point to the same byte within the page as was passed in. 98 */ 99 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page, 100 unsigned long offset, size_t size, 101 enum dma_data_direction direction, 102 unsigned long attrs) 103 { 104 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset, 105 size, dma_get_mask(dev), direction, attrs); 106 } 107 108 109 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, 110 size_t size, enum dma_data_direction direction, 111 unsigned long attrs) 112 { 113 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction, 114 attrs); 115 } 116 117 118 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, 119 int nelems, enum dma_data_direction direction, 120 unsigned long attrs) 121 { 122 return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems, 123 dma_get_mask(dev), direction, attrs); 124 } 125 126 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, 127 int nelems, enum dma_data_direction direction, 128 unsigned long attrs) 129 { 130 ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, 131 direction, attrs); 132 } 133 134 static bool dma_iommu_bypass_supported(struct device *dev, u64 mask) 135 { 136 struct pci_dev *pdev = to_pci_dev(dev); 137 struct pci_controller *phb = pci_bus_to_host(pdev->bus); 138 139 if (iommu_fixed_is_weak || !phb->controller_ops.iommu_bypass_supported) 140 return false; 141 return phb->controller_ops.iommu_bypass_supported(pdev, mask); 142 } 143 144 /* We support DMA to/from any memory page via the iommu */ 145 int dma_iommu_dma_supported(struct device *dev, u64 mask) 146 { 147 struct iommu_table *tbl = get_iommu_table_base(dev); 148 149 if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) { 150 /* 151 * dma_iommu_bypass_supported() sets dma_max when there is 152 * 1:1 mapping but it is somehow limited. 153 * ibm,pmemory is one example. 154 */ 155 dev->dma_ops_bypass = dev->bus_dma_limit == 0; 156 if (!dev->dma_ops_bypass) 157 dev_warn(dev, 158 "iommu: 64-bit OK but direct DMA is limited by %llx\n", 159 dev->bus_dma_limit); 160 else 161 dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n"); 162 return 1; 163 } 164 165 if (!tbl) { 166 dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask); 167 return 0; 168 } 169 170 if (tbl->it_offset > (mask >> tbl->it_page_shift)) { 171 dev_info(dev, "Warning: IOMMU offset too big for device mask\n"); 172 dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n", 173 mask, tbl->it_offset << tbl->it_page_shift); 174 return 0; 175 } 176 177 dev_dbg(dev, "iommu: not 64-bit, using default ops\n"); 178 dev->dma_ops_bypass = false; 179 return 1; 180 } 181 182 u64 dma_iommu_get_required_mask(struct device *dev) 183 { 184 struct iommu_table *tbl = get_iommu_table_base(dev); 185 u64 mask; 186 187 if (!tbl) 188 return 0; 189 190 mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) + 191 tbl->it_page_shift - 1); 192 mask += mask - 1; 193 194 return mask; 195 } 196 197 const struct dma_map_ops dma_iommu_ops = { 198 .alloc = dma_iommu_alloc_coherent, 199 .free = dma_iommu_free_coherent, 200 .map_sg = dma_iommu_map_sg, 201 .unmap_sg = dma_iommu_unmap_sg, 202 .dma_supported = dma_iommu_dma_supported, 203 .map_page = dma_iommu_map_page, 204 .unmap_page = dma_iommu_unmap_page, 205 .get_required_mask = dma_iommu_get_required_mask, 206 .mmap = dma_common_mmap, 207 .get_sgtable = dma_common_get_sgtable, 208 .alloc_pages = dma_common_alloc_pages, 209 .free_pages = dma_common_free_pages, 210 }; 211