1 /* 2 * SWIOTLB-based DMA API implementation 3 * 4 * Copyright (C) 2012 ARM Ltd. 5 * Author: Catalin Marinas <catalin.marinas@arm.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/gfp.h> 21 #include <linux/export.h> 22 #include <linux/slab.h> 23 #include <linux/dma-mapping.h> 24 #include <linux/dma-contiguous.h> 25 #include <linux/of.h> 26 #include <linux/platform_device.h> 27 #include <linux/vmalloc.h> 28 #include <linux/swiotlb.h> 29 #include <linux/amba/bus.h> 30 31 #include <asm/cacheflush.h> 32 33 struct dma_map_ops *dma_ops; 34 EXPORT_SYMBOL(dma_ops); 35 36 static pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot, 37 bool coherent) 38 { 39 if (!coherent || dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs)) 40 return pgprot_writecombine(prot); 41 return prot; 42 } 43 44 static void *__dma_alloc_coherent(struct device *dev, size_t size, 45 dma_addr_t *dma_handle, gfp_t flags, 46 struct dma_attrs *attrs) 47 { 48 if (dev == NULL) { 49 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n"); 50 return NULL; 51 } 52 53 if (IS_ENABLED(CONFIG_ZONE_DMA) && 54 dev->coherent_dma_mask <= DMA_BIT_MASK(32)) 55 flags |= GFP_DMA; 56 if (IS_ENABLED(CONFIG_DMA_CMA)) { 57 struct page *page; 58 59 size = PAGE_ALIGN(size); 60 page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT, 61 get_order(size)); 62 if (!page) 63 return NULL; 64 65 *dma_handle = phys_to_dma(dev, page_to_phys(page)); 66 return page_address(page); 67 } else { 68 return swiotlb_alloc_coherent(dev, size, dma_handle, flags); 69 } 70 } 71 72 static void __dma_free_coherent(struct device *dev, size_t size, 73 void *vaddr, dma_addr_t dma_handle, 74 struct dma_attrs *attrs) 75 { 76 if (dev == NULL) { 77 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n"); 78 return; 79 } 80 81 if (IS_ENABLED(CONFIG_DMA_CMA)) { 82 phys_addr_t paddr = dma_to_phys(dev, dma_handle); 83 84 dma_release_from_contiguous(dev, 85 phys_to_page(paddr), 86 size >> PAGE_SHIFT); 87 } else { 88 swiotlb_free_coherent(dev, size, vaddr, dma_handle); 89 } 90 } 91 92 static void *__dma_alloc_noncoherent(struct device *dev, size_t size, 93 dma_addr_t *dma_handle, gfp_t flags, 94 struct dma_attrs *attrs) 95 { 96 struct page *page, **map; 97 void *ptr, *coherent_ptr; 98 int order, i; 99 100 size = PAGE_ALIGN(size); 101 order = get_order(size); 102 103 ptr = __dma_alloc_coherent(dev, size, dma_handle, flags, attrs); 104 if (!ptr) 105 goto no_mem; 106 map = kmalloc(sizeof(struct page *) << order, flags & ~GFP_DMA); 107 if (!map) 108 goto no_map; 109 110 /* remove any dirty cache lines on the kernel alias */ 111 __dma_flush_range(ptr, ptr + size); 112 113 /* create a coherent mapping */ 114 page = virt_to_page(ptr); 115 for (i = 0; i < (size >> PAGE_SHIFT); i++) 116 map[i] = page + i; 117 coherent_ptr = vmap(map, size >> PAGE_SHIFT, VM_MAP, 118 __get_dma_pgprot(attrs, __pgprot(PROT_NORMAL_NC), false)); 119 kfree(map); 120 if (!coherent_ptr) 121 goto no_map; 122 123 return coherent_ptr; 124 125 no_map: 126 __dma_free_coherent(dev, size, ptr, *dma_handle, attrs); 127 no_mem: 128 *dma_handle = ~0; 129 return NULL; 130 } 131 132 static void __dma_free_noncoherent(struct device *dev, size_t size, 133 void *vaddr, dma_addr_t dma_handle, 134 struct dma_attrs *attrs) 135 { 136 void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle)); 137 138 vunmap(vaddr); 139 __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs); 140 } 141 142 static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page, 143 unsigned long offset, size_t size, 144 enum dma_data_direction dir, 145 struct dma_attrs *attrs) 146 { 147 dma_addr_t dev_addr; 148 149 dev_addr = swiotlb_map_page(dev, page, offset, size, dir, attrs); 150 __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 151 152 return dev_addr; 153 } 154 155 156 static void __swiotlb_unmap_page(struct device *dev, dma_addr_t dev_addr, 157 size_t size, enum dma_data_direction dir, 158 struct dma_attrs *attrs) 159 { 160 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 161 swiotlb_unmap_page(dev, dev_addr, size, dir, attrs); 162 } 163 164 static int __swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl, 165 int nelems, enum dma_data_direction dir, 166 struct dma_attrs *attrs) 167 { 168 struct scatterlist *sg; 169 int i, ret; 170 171 ret = swiotlb_map_sg_attrs(dev, sgl, nelems, dir, attrs); 172 for_each_sg(sgl, sg, ret, i) 173 __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 174 sg->length, dir); 175 176 return ret; 177 } 178 179 static void __swiotlb_unmap_sg_attrs(struct device *dev, 180 struct scatterlist *sgl, int nelems, 181 enum dma_data_direction dir, 182 struct dma_attrs *attrs) 183 { 184 struct scatterlist *sg; 185 int i; 186 187 for_each_sg(sgl, sg, nelems, i) 188 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 189 sg->length, dir); 190 swiotlb_unmap_sg_attrs(dev, sgl, nelems, dir, attrs); 191 } 192 193 static void __swiotlb_sync_single_for_cpu(struct device *dev, 194 dma_addr_t dev_addr, size_t size, 195 enum dma_data_direction dir) 196 { 197 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 198 swiotlb_sync_single_for_cpu(dev, dev_addr, size, dir); 199 } 200 201 static void __swiotlb_sync_single_for_device(struct device *dev, 202 dma_addr_t dev_addr, size_t size, 203 enum dma_data_direction dir) 204 { 205 swiotlb_sync_single_for_device(dev, dev_addr, size, dir); 206 __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 207 } 208 209 static void __swiotlb_sync_sg_for_cpu(struct device *dev, 210 struct scatterlist *sgl, int nelems, 211 enum dma_data_direction dir) 212 { 213 struct scatterlist *sg; 214 int i; 215 216 for_each_sg(sgl, sg, nelems, i) 217 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 218 sg->length, dir); 219 swiotlb_sync_sg_for_cpu(dev, sgl, nelems, dir); 220 } 221 222 static void __swiotlb_sync_sg_for_device(struct device *dev, 223 struct scatterlist *sgl, int nelems, 224 enum dma_data_direction dir) 225 { 226 struct scatterlist *sg; 227 int i; 228 229 swiotlb_sync_sg_for_device(dev, sgl, nelems, dir); 230 for_each_sg(sgl, sg, nelems, i) 231 __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 232 sg->length, dir); 233 } 234 235 /* vma->vm_page_prot must be set appropriately before calling this function */ 236 static int __dma_common_mmap(struct device *dev, struct vm_area_struct *vma, 237 void *cpu_addr, dma_addr_t dma_addr, size_t size) 238 { 239 int ret = -ENXIO; 240 unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >> 241 PAGE_SHIFT; 242 unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; 243 unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT; 244 unsigned long off = vma->vm_pgoff; 245 246 if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) 247 return ret; 248 249 if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) { 250 ret = remap_pfn_range(vma, vma->vm_start, 251 pfn + off, 252 vma->vm_end - vma->vm_start, 253 vma->vm_page_prot); 254 } 255 256 return ret; 257 } 258 259 static int __swiotlb_mmap_noncoherent(struct device *dev, 260 struct vm_area_struct *vma, 261 void *cpu_addr, dma_addr_t dma_addr, size_t size, 262 struct dma_attrs *attrs) 263 { 264 vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot, false); 265 return __dma_common_mmap(dev, vma, cpu_addr, dma_addr, size); 266 } 267 268 static int __swiotlb_mmap_coherent(struct device *dev, 269 struct vm_area_struct *vma, 270 void *cpu_addr, dma_addr_t dma_addr, size_t size, 271 struct dma_attrs *attrs) 272 { 273 /* Just use whatever page_prot attributes were specified */ 274 return __dma_common_mmap(dev, vma, cpu_addr, dma_addr, size); 275 } 276 277 struct dma_map_ops noncoherent_swiotlb_dma_ops = { 278 .alloc = __dma_alloc_noncoherent, 279 .free = __dma_free_noncoherent, 280 .mmap = __swiotlb_mmap_noncoherent, 281 .map_page = __swiotlb_map_page, 282 .unmap_page = __swiotlb_unmap_page, 283 .map_sg = __swiotlb_map_sg_attrs, 284 .unmap_sg = __swiotlb_unmap_sg_attrs, 285 .sync_single_for_cpu = __swiotlb_sync_single_for_cpu, 286 .sync_single_for_device = __swiotlb_sync_single_for_device, 287 .sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu, 288 .sync_sg_for_device = __swiotlb_sync_sg_for_device, 289 .dma_supported = swiotlb_dma_supported, 290 .mapping_error = swiotlb_dma_mapping_error, 291 }; 292 EXPORT_SYMBOL(noncoherent_swiotlb_dma_ops); 293 294 struct dma_map_ops coherent_swiotlb_dma_ops = { 295 .alloc = __dma_alloc_coherent, 296 .free = __dma_free_coherent, 297 .mmap = __swiotlb_mmap_coherent, 298 .map_page = swiotlb_map_page, 299 .unmap_page = swiotlb_unmap_page, 300 .map_sg = swiotlb_map_sg_attrs, 301 .unmap_sg = swiotlb_unmap_sg_attrs, 302 .sync_single_for_cpu = swiotlb_sync_single_for_cpu, 303 .sync_single_for_device = swiotlb_sync_single_for_device, 304 .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu, 305 .sync_sg_for_device = swiotlb_sync_sg_for_device, 306 .dma_supported = swiotlb_dma_supported, 307 .mapping_error = swiotlb_dma_mapping_error, 308 }; 309 EXPORT_SYMBOL(coherent_swiotlb_dma_ops); 310 311 static int dma_bus_notifier(struct notifier_block *nb, 312 unsigned long event, void *_dev) 313 { 314 struct device *dev = _dev; 315 316 if (event != BUS_NOTIFY_ADD_DEVICE) 317 return NOTIFY_DONE; 318 319 if (of_property_read_bool(dev->of_node, "dma-coherent")) 320 set_dma_ops(dev, &coherent_swiotlb_dma_ops); 321 322 return NOTIFY_OK; 323 } 324 325 static struct notifier_block platform_bus_nb = { 326 .notifier_call = dma_bus_notifier, 327 }; 328 329 static struct notifier_block amba_bus_nb = { 330 .notifier_call = dma_bus_notifier, 331 }; 332 333 extern int swiotlb_late_init_with_default_size(size_t default_size); 334 335 static int __init swiotlb_late_init(void) 336 { 337 size_t swiotlb_size = min(SZ_64M, MAX_ORDER_NR_PAGES << PAGE_SHIFT); 338 339 /* 340 * These must be registered before of_platform_populate(). 341 */ 342 bus_register_notifier(&platform_bus_type, &platform_bus_nb); 343 bus_register_notifier(&amba_bustype, &amba_bus_nb); 344 345 dma_ops = &noncoherent_swiotlb_dma_ops; 346 347 return swiotlb_late_init_with_default_size(swiotlb_size); 348 } 349 arch_initcall(swiotlb_late_init); 350 351 #define PREALLOC_DMA_DEBUG_ENTRIES 4096 352 353 static int __init dma_debug_do_init(void) 354 { 355 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 356 return 0; 357 } 358 fs_initcall(dma_debug_do_init); 359