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 /* 14 * Generic iommu implementation 15 */ 16 17 /* 18 * The coherent mask may be smaller than the real mask, check if we can 19 * really use a direct window. 20 */ 21 static inline bool dma_iommu_alloc_bypass(struct device *dev) 22 { 23 return dev->archdata.iommu_bypass && !iommu_fixed_is_weak && 24 dma_direct_supported(dev, dev->coherent_dma_mask); 25 } 26 27 static inline bool dma_iommu_map_bypass(struct device *dev, 28 unsigned long attrs) 29 { 30 return dev->archdata.iommu_bypass && 31 (!iommu_fixed_is_weak || (attrs & DMA_ATTR_WEAK_ORDERING)); 32 } 33 34 /* Allocates a contiguous real buffer and creates mappings over it. 35 * Returns the virtual address of the buffer and sets dma_handle 36 * to the dma address (mapping) of the first page. 37 */ 38 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size, 39 dma_addr_t *dma_handle, gfp_t flag, 40 unsigned long attrs) 41 { 42 if (dma_iommu_alloc_bypass(dev)) 43 return dma_direct_alloc(dev, size, dma_handle, flag, attrs); 44 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size, 45 dma_handle, dev->coherent_dma_mask, flag, 46 dev_to_node(dev)); 47 } 48 49 static void dma_iommu_free_coherent(struct device *dev, size_t size, 50 void *vaddr, dma_addr_t dma_handle, 51 unsigned long attrs) 52 { 53 if (dma_iommu_alloc_bypass(dev)) 54 dma_direct_free(dev, size, vaddr, dma_handle, attrs); 55 else 56 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, 57 dma_handle); 58 } 59 60 /* Creates TCEs for a user provided buffer. The user buffer must be 61 * contiguous real kernel storage (not vmalloc). The address passed here 62 * comprises a page address and offset into that page. The dma_addr_t 63 * returned will point to the same byte within the page as was passed in. 64 */ 65 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page, 66 unsigned long offset, size_t size, 67 enum dma_data_direction direction, 68 unsigned long attrs) 69 { 70 if (dma_iommu_map_bypass(dev, attrs)) 71 return dma_direct_map_page(dev, page, offset, size, direction, 72 attrs); 73 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset, 74 size, dma_get_mask(dev), direction, attrs); 75 } 76 77 78 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, 79 size_t size, enum dma_data_direction direction, 80 unsigned long attrs) 81 { 82 if (!dma_iommu_map_bypass(dev, attrs)) 83 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, 84 direction, attrs); 85 else 86 dma_direct_unmap_page(dev, dma_handle, size, direction, attrs); 87 } 88 89 90 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, 91 int nelems, enum dma_data_direction direction, 92 unsigned long attrs) 93 { 94 if (dma_iommu_map_bypass(dev, attrs)) 95 return dma_direct_map_sg(dev, sglist, nelems, direction, attrs); 96 return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems, 97 dma_get_mask(dev), direction, attrs); 98 } 99 100 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, 101 int nelems, enum dma_data_direction direction, 102 unsigned long attrs) 103 { 104 if (!dma_iommu_map_bypass(dev, attrs)) 105 ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, 106 direction, attrs); 107 else 108 dma_direct_unmap_sg(dev, sglist, nelems, direction, attrs); 109 } 110 111 static bool dma_iommu_bypass_supported(struct device *dev, u64 mask) 112 { 113 struct pci_dev *pdev = to_pci_dev(dev); 114 struct pci_controller *phb = pci_bus_to_host(pdev->bus); 115 116 return phb->controller_ops.iommu_bypass_supported && 117 phb->controller_ops.iommu_bypass_supported(pdev, mask); 118 } 119 120 /* We support DMA to/from any memory page via the iommu */ 121 int dma_iommu_dma_supported(struct device *dev, u64 mask) 122 { 123 struct iommu_table *tbl = get_iommu_table_base(dev); 124 125 if (!tbl) { 126 dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx" 127 ", table unavailable\n", mask); 128 return 0; 129 } 130 131 if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) { 132 dev->archdata.iommu_bypass = true; 133 dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n"); 134 return 1; 135 } 136 137 if (tbl->it_offset > (mask >> tbl->it_page_shift)) { 138 dev_info(dev, "Warning: IOMMU offset too big for device mask\n"); 139 dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n", 140 mask, tbl->it_offset << tbl->it_page_shift); 141 return 0; 142 } 143 144 dev_dbg(dev, "iommu: not 64-bit, using default ops\n"); 145 dev->archdata.iommu_bypass = false; 146 return 1; 147 } 148 149 u64 dma_iommu_get_required_mask(struct device *dev) 150 { 151 struct iommu_table *tbl = get_iommu_table_base(dev); 152 u64 mask; 153 154 if (!tbl) 155 return 0; 156 157 if (dev_is_pci(dev)) { 158 u64 bypass_mask = dma_direct_get_required_mask(dev); 159 160 if (dma_iommu_bypass_supported(dev, bypass_mask)) 161 return bypass_mask; 162 } 163 164 mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1); 165 mask += mask - 1; 166 167 return mask; 168 } 169 170 static void dma_iommu_sync_for_cpu(struct device *dev, dma_addr_t addr, 171 size_t size, enum dma_data_direction dir) 172 { 173 if (dma_iommu_alloc_bypass(dev)) 174 dma_direct_sync_single_for_cpu(dev, addr, size, dir); 175 } 176 177 static void dma_iommu_sync_for_device(struct device *dev, dma_addr_t addr, 178 size_t sz, enum dma_data_direction dir) 179 { 180 if (dma_iommu_alloc_bypass(dev)) 181 dma_direct_sync_single_for_device(dev, addr, sz, dir); 182 } 183 184 extern void dma_iommu_sync_sg_for_cpu(struct device *dev, 185 struct scatterlist *sgl, int nents, enum dma_data_direction dir) 186 { 187 if (dma_iommu_alloc_bypass(dev)) 188 dma_direct_sync_sg_for_cpu(dev, sgl, nents, dir); 189 } 190 191 extern void dma_iommu_sync_sg_for_device(struct device *dev, 192 struct scatterlist *sgl, int nents, enum dma_data_direction dir) 193 { 194 if (dma_iommu_alloc_bypass(dev)) 195 dma_direct_sync_sg_for_device(dev, sgl, nents, dir); 196 } 197 198 const struct dma_map_ops dma_iommu_ops = { 199 .alloc = dma_iommu_alloc_coherent, 200 .free = dma_iommu_free_coherent, 201 .map_sg = dma_iommu_map_sg, 202 .unmap_sg = dma_iommu_unmap_sg, 203 .dma_supported = dma_iommu_dma_supported, 204 .map_page = dma_iommu_map_page, 205 .unmap_page = dma_iommu_unmap_page, 206 .get_required_mask = dma_iommu_get_required_mask, 207 .sync_single_for_cpu = dma_iommu_sync_for_cpu, 208 .sync_single_for_device = dma_iommu_sync_for_device, 209 .sync_sg_for_cpu = dma_iommu_sync_sg_for_cpu, 210 .sync_sg_for_device = dma_iommu_sync_sg_for_device, 211 }; 212