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/genalloc.h> 24#include <linux/dma-mapping.h> 25#include <linux/dma-contiguous.h> 26#include <linux/vmalloc.h> 27#include <linux/swiotlb.h> 28 29#include <asm/cacheflush.h> 30 31struct dma_map_ops *dma_ops; 32EXPORT_SYMBOL(dma_ops); 33 34static pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot, 35 bool coherent) 36{ 37 if (!coherent || dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs)) 38 return pgprot_writecombine(prot); 39 return prot; 40} 41 42static struct gen_pool *atomic_pool; 43 44#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K 45static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE; 46 47static int __init early_coherent_pool(char *p) 48{ 49 atomic_pool_size = memparse(p, &p); 50 return 0; 51} 52early_param("coherent_pool", early_coherent_pool); 53 54static void *__alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags) 55{ 56 unsigned long val; 57 void *ptr = NULL; 58 59 if (!atomic_pool) { 60 WARN(1, "coherent pool not initialised!\n"); 61 return NULL; 62 } 63 64 val = gen_pool_alloc(atomic_pool, size); 65 if (val) { 66 phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val); 67 68 *ret_page = phys_to_page(phys); 69 ptr = (void *)val; 70 memset(ptr, 0, size); 71 } 72 73 return ptr; 74} 75 76static bool __in_atomic_pool(void *start, size_t size) 77{ 78 return addr_in_gen_pool(atomic_pool, (unsigned long)start, size); 79} 80 81static int __free_from_pool(void *start, size_t size) 82{ 83 if (!__in_atomic_pool(start, size)) 84 return 0; 85 86 gen_pool_free(atomic_pool, (unsigned long)start, size); 87 88 return 1; 89} 90 91static void *__dma_alloc_coherent(struct device *dev, size_t size, 92 dma_addr_t *dma_handle, gfp_t flags, 93 struct dma_attrs *attrs) 94{ 95 if (dev == NULL) { 96 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n"); 97 return NULL; 98 } 99 100 if (IS_ENABLED(CONFIG_ZONE_DMA) && 101 dev->coherent_dma_mask <= DMA_BIT_MASK(32)) 102 flags |= GFP_DMA; 103 if (IS_ENABLED(CONFIG_DMA_CMA) && (flags & __GFP_WAIT)) { 104 struct page *page; 105 void *addr; 106 107 page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT, 108 get_order(size)); 109 if (!page) 110 return NULL; 111 112 *dma_handle = phys_to_dma(dev, page_to_phys(page)); 113 addr = page_address(page); 114 memset(addr, 0, size); 115 return addr; 116 } else { 117 return swiotlb_alloc_coherent(dev, size, dma_handle, flags); 118 } 119} 120 121static void __dma_free_coherent(struct device *dev, size_t size, 122 void *vaddr, dma_addr_t dma_handle, 123 struct dma_attrs *attrs) 124{ 125 bool freed; 126 phys_addr_t paddr = dma_to_phys(dev, dma_handle); 127 128 if (dev == NULL) { 129 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n"); 130 return; 131 } 132 133 freed = dma_release_from_contiguous(dev, 134 phys_to_page(paddr), 135 size >> PAGE_SHIFT); 136 if (!freed) 137 swiotlb_free_coherent(dev, size, vaddr, dma_handle); 138} 139 140static void *__dma_alloc(struct device *dev, size_t size, 141 dma_addr_t *dma_handle, gfp_t flags, 142 struct dma_attrs *attrs) 143{ 144 struct page *page; 145 void *ptr, *coherent_ptr; 146 bool coherent = is_device_dma_coherent(dev); 147 148 size = PAGE_ALIGN(size); 149 150 if (!coherent && !(flags & __GFP_WAIT)) { 151 struct page *page = NULL; 152 void *addr = __alloc_from_pool(size, &page, flags); 153 154 if (addr) 155 *dma_handle = phys_to_dma(dev, page_to_phys(page)); 156 157 return addr; 158 } 159 160 ptr = __dma_alloc_coherent(dev, size, dma_handle, flags, attrs); 161 if (!ptr) 162 goto no_mem; 163 164 /* no need for non-cacheable mapping if coherent */ 165 if (coherent) 166 return ptr; 167 168 /* remove any dirty cache lines on the kernel alias */ 169 __dma_flush_range(ptr, ptr + size); 170 171 /* create a coherent mapping */ 172 page = virt_to_page(ptr); 173 coherent_ptr = dma_common_contiguous_remap(page, size, VM_USERMAP, 174 __get_dma_pgprot(attrs, 175 __pgprot(PROT_NORMAL_NC), false), 176 NULL); 177 if (!coherent_ptr) 178 goto no_map; 179 180 return coherent_ptr; 181 182no_map: 183 __dma_free_coherent(dev, size, ptr, *dma_handle, attrs); 184no_mem: 185 *dma_handle = DMA_ERROR_CODE; 186 return NULL; 187} 188 189static void __dma_free(struct device *dev, size_t size, 190 void *vaddr, dma_addr_t dma_handle, 191 struct dma_attrs *attrs) 192{ 193 void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle)); 194 195 size = PAGE_ALIGN(size); 196 197 if (!is_device_dma_coherent(dev)) { 198 if (__free_from_pool(vaddr, size)) 199 return; 200 vunmap(vaddr); 201 } 202 __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs); 203} 204 205static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page, 206 unsigned long offset, size_t size, 207 enum dma_data_direction dir, 208 struct dma_attrs *attrs) 209{ 210 dma_addr_t dev_addr; 211 212 dev_addr = swiotlb_map_page(dev, page, offset, size, dir, attrs); 213 if (!is_device_dma_coherent(dev)) 214 __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 215 216 return dev_addr; 217} 218 219 220static void __swiotlb_unmap_page(struct device *dev, dma_addr_t dev_addr, 221 size_t size, enum dma_data_direction dir, 222 struct dma_attrs *attrs) 223{ 224 if (!is_device_dma_coherent(dev)) 225 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 226 swiotlb_unmap_page(dev, dev_addr, size, dir, attrs); 227} 228 229static int __swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl, 230 int nelems, enum dma_data_direction dir, 231 struct dma_attrs *attrs) 232{ 233 struct scatterlist *sg; 234 int i, ret; 235 236 ret = swiotlb_map_sg_attrs(dev, sgl, nelems, dir, attrs); 237 if (!is_device_dma_coherent(dev)) 238 for_each_sg(sgl, sg, ret, i) 239 __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 240 sg->length, dir); 241 242 return ret; 243} 244 245static void __swiotlb_unmap_sg_attrs(struct device *dev, 246 struct scatterlist *sgl, int nelems, 247 enum dma_data_direction dir, 248 struct dma_attrs *attrs) 249{ 250 struct scatterlist *sg; 251 int i; 252 253 if (!is_device_dma_coherent(dev)) 254 for_each_sg(sgl, sg, nelems, i) 255 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 256 sg->length, dir); 257 swiotlb_unmap_sg_attrs(dev, sgl, nelems, dir, attrs); 258} 259 260static void __swiotlb_sync_single_for_cpu(struct device *dev, 261 dma_addr_t dev_addr, size_t size, 262 enum dma_data_direction dir) 263{ 264 if (!is_device_dma_coherent(dev)) 265 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 266 swiotlb_sync_single_for_cpu(dev, dev_addr, size, dir); 267} 268 269static void __swiotlb_sync_single_for_device(struct device *dev, 270 dma_addr_t dev_addr, size_t size, 271 enum dma_data_direction dir) 272{ 273 swiotlb_sync_single_for_device(dev, dev_addr, size, dir); 274 if (!is_device_dma_coherent(dev)) 275 __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir); 276} 277 278static void __swiotlb_sync_sg_for_cpu(struct device *dev, 279 struct scatterlist *sgl, int nelems, 280 enum dma_data_direction dir) 281{ 282 struct scatterlist *sg; 283 int i; 284 285 if (!is_device_dma_coherent(dev)) 286 for_each_sg(sgl, sg, nelems, i) 287 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 288 sg->length, dir); 289 swiotlb_sync_sg_for_cpu(dev, sgl, nelems, dir); 290} 291 292static void __swiotlb_sync_sg_for_device(struct device *dev, 293 struct scatterlist *sgl, int nelems, 294 enum dma_data_direction dir) 295{ 296 struct scatterlist *sg; 297 int i; 298 299 swiotlb_sync_sg_for_device(dev, sgl, nelems, dir); 300 if (!is_device_dma_coherent(dev)) 301 for_each_sg(sgl, sg, nelems, i) 302 __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)), 303 sg->length, dir); 304} 305 306/* vma->vm_page_prot must be set appropriately before calling this function */ 307static int __dma_common_mmap(struct device *dev, struct vm_area_struct *vma, 308 void *cpu_addr, dma_addr_t dma_addr, size_t size) 309{ 310 int ret = -ENXIO; 311 unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >> 312 PAGE_SHIFT; 313 unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; 314 unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT; 315 unsigned long off = vma->vm_pgoff; 316 317 if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) 318 return ret; 319 320 if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) { 321 ret = remap_pfn_range(vma, vma->vm_start, 322 pfn + off, 323 vma->vm_end - vma->vm_start, 324 vma->vm_page_prot); 325 } 326 327 return ret; 328} 329 330static int __swiotlb_mmap(struct device *dev, 331 struct vm_area_struct *vma, 332 void *cpu_addr, dma_addr_t dma_addr, size_t size, 333 struct dma_attrs *attrs) 334{ 335 vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot, 336 is_device_dma_coherent(dev)); 337 return __dma_common_mmap(dev, vma, cpu_addr, dma_addr, size); 338} 339 340static struct dma_map_ops swiotlb_dma_ops = { 341 .alloc = __dma_alloc, 342 .free = __dma_free, 343 .mmap = __swiotlb_mmap, 344 .map_page = __swiotlb_map_page, 345 .unmap_page = __swiotlb_unmap_page, 346 .map_sg = __swiotlb_map_sg_attrs, 347 .unmap_sg = __swiotlb_unmap_sg_attrs, 348 .sync_single_for_cpu = __swiotlb_sync_single_for_cpu, 349 .sync_single_for_device = __swiotlb_sync_single_for_device, 350 .sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu, 351 .sync_sg_for_device = __swiotlb_sync_sg_for_device, 352 .dma_supported = swiotlb_dma_supported, 353 .mapping_error = swiotlb_dma_mapping_error, 354}; 355 356static int __init atomic_pool_init(void) 357{ 358 pgprot_t prot = __pgprot(PROT_NORMAL_NC); 359 unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT; 360 struct page *page; 361 void *addr; 362 unsigned int pool_size_order = get_order(atomic_pool_size); 363 364 if (dev_get_cma_area(NULL)) 365 page = dma_alloc_from_contiguous(NULL, nr_pages, 366 pool_size_order); 367 else 368 page = alloc_pages(GFP_DMA, pool_size_order); 369 370 if (page) { 371 int ret; 372 void *page_addr = page_address(page); 373 374 memset(page_addr, 0, atomic_pool_size); 375 __dma_flush_range(page_addr, page_addr + atomic_pool_size); 376 377 atomic_pool = gen_pool_create(PAGE_SHIFT, -1); 378 if (!atomic_pool) 379 goto free_page; 380 381 addr = dma_common_contiguous_remap(page, atomic_pool_size, 382 VM_USERMAP, prot, atomic_pool_init); 383 384 if (!addr) 385 goto destroy_genpool; 386 387 ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr, 388 page_to_phys(page), 389 atomic_pool_size, -1); 390 if (ret) 391 goto remove_mapping; 392 393 gen_pool_set_algo(atomic_pool, 394 gen_pool_first_fit_order_align, 395 (void *)PAGE_SHIFT); 396 397 pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n", 398 atomic_pool_size / 1024); 399 return 0; 400 } 401 goto out; 402 403remove_mapping: 404 dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP); 405destroy_genpool: 406 gen_pool_destroy(atomic_pool); 407 atomic_pool = NULL; 408free_page: 409 if (!dma_release_from_contiguous(NULL, page, nr_pages)) 410 __free_pages(page, pool_size_order); 411out: 412 pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n", 413 atomic_pool_size / 1024); 414 return -ENOMEM; 415} 416 417static int __init arm64_dma_init(void) 418{ 419 int ret; 420 421 dma_ops = &swiotlb_dma_ops; 422 423 ret = atomic_pool_init(); 424 425 return ret; 426} 427arch_initcall(arm64_dma_init); 428 429#define PREALLOC_DMA_DEBUG_ENTRIES 4096 430 431static int __init dma_debug_do_init(void) 432{ 433 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 434 return 0; 435} 436fs_initcall(dma_debug_do_init); 437