arch/arm64/mm/dma-mapping.c

   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
  31 struct dma_map_ops *dma_ops;
  32 EXPORT_SYMBOL(dma_ops);
  33
  34 static 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
  42 static struct gen_pool *atomic_pool;
  43
  44 #define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
  45 static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE;
  46
  47 static int __init early_coherent_pool(char *p)
  48 {
  49         atomic_pool_size = memparse(p, &p);
  50         return 0;
  51 }
  52 early_param("coherent_pool", early_coherent_pool);
  53
  54 static 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
  76 static bool __in_atomic_pool(void *start, size_t size)
  77 {
  78         return addr_in_gen_pool(atomic_pool, (unsigned long)start, size);
  79 }
  80
  81 static 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
  91 static 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 (dev_get_cma_area(dev) && gfpflags_allow_blocking(flags)) {
 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
 121 static 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
 140 static 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         pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, false);
 148
 149         size = PAGE_ALIGN(size);
 150
 151         if (!coherent && !gfpflags_allow_blocking(flags)) {
 152                 struct page *page = NULL;
 153                 void *addr = __alloc_from_pool(size, &page, flags);
 154
 155                 if (addr)
 156                         *dma_handle = phys_to_dma(dev, page_to_phys(page));
 157
 158                 return addr;
 159         }
 160
 161         ptr = __dma_alloc_coherent(dev, size, dma_handle, flags, attrs);
 162         if (!ptr)
 163                 goto no_mem;
 164
 165         /* no need for non-cacheable mapping if coherent */
 166         if (coherent)
 167                 return ptr;
 168
 169         /* remove any dirty cache lines on the kernel alias */
 170         __dma_flush_range(ptr, ptr + size);
 171
 172         /* create a coherent mapping */
 173         page = virt_to_page(ptr);
 174         coherent_ptr = dma_common_contiguous_remap(page, size, VM_USERMAP,
 175                                                    prot, NULL);
 176         if (!coherent_ptr)
 177                 goto no_map;
 178
 179         return coherent_ptr;
 180
 181 no_map:
 182         __dma_free_coherent(dev, size, ptr, *dma_handle, attrs);
 183 no_mem:
 184         *dma_handle = DMA_ERROR_CODE;
 185         return NULL;
 186 }
 187
 188 static void __dma_free(struct device *dev, size_t size,
 189                        void *vaddr, dma_addr_t dma_handle,
 190                        struct dma_attrs *attrs)
 191 {
 192         void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
 193
 194         size = PAGE_ALIGN(size);
 195
 196         if (!is_device_dma_coherent(dev)) {
 197                 if (__free_from_pool(vaddr, size))
 198                         return;
 199                 vunmap(vaddr);
 200         }
 201         __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
 202 }
 203
 204 static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page,
 205                                      unsigned long offset, size_t size,
 206                                      enum dma_data_direction dir,
 207                                      struct dma_attrs *attrs)
 208 {
 209         dma_addr_t dev_addr;
 210
 211         dev_addr = swiotlb_map_page(dev, page, offset, size, dir, attrs);
 212         if (!is_device_dma_coherent(dev))
 213                 __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
 214
 215         return dev_addr;
 216 }
 217
 218
 219 static void __swiotlb_unmap_page(struct device *dev, dma_addr_t dev_addr,
 220                                  size_t size, enum dma_data_direction dir,
 221                                  struct dma_attrs *attrs)
 222 {
 223         if (!is_device_dma_coherent(dev))
 224                 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
 225         swiotlb_unmap_page(dev, dev_addr, size, dir, attrs);
 226 }
 227
 228 static int __swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
 229                                   int nelems, enum dma_data_direction dir,
 230                                   struct dma_attrs *attrs)
 231 {
 232         struct scatterlist *sg;
 233         int i, ret;
 234
 235         ret = swiotlb_map_sg_attrs(dev, sgl, nelems, dir, attrs);
 236         if (!is_device_dma_coherent(dev))
 237                 for_each_sg(sgl, sg, ret, i)
 238                         __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
 239                                        sg->length, dir);
 240
 241         return ret;
 242 }
 243
 244 static void __swiotlb_unmap_sg_attrs(struct device *dev,
 245                                      struct scatterlist *sgl, int nelems,
 246                                      enum dma_data_direction dir,
 247                                      struct dma_attrs *attrs)
 248 {
 249         struct scatterlist *sg;
 250         int i;
 251
 252         if (!is_device_dma_coherent(dev))
 253                 for_each_sg(sgl, sg, nelems, i)
 254                         __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
 255                                          sg->length, dir);
 256         swiotlb_unmap_sg_attrs(dev, sgl, nelems, dir, attrs);
 257 }
 258
 259 static void __swiotlb_sync_single_for_cpu(struct device *dev,
 260                                           dma_addr_t dev_addr, size_t size,
 261                                           enum dma_data_direction dir)
 262 {
 263         if (!is_device_dma_coherent(dev))
 264                 __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
 265         swiotlb_sync_single_for_cpu(dev, dev_addr, size, dir);
 266 }
 267
 268 static void __swiotlb_sync_single_for_device(struct device *dev,
 269                                              dma_addr_t dev_addr, size_t size,
 270                                              enum dma_data_direction dir)
 271 {
 272         swiotlb_sync_single_for_device(dev, dev_addr, size, dir);
 273         if (!is_device_dma_coherent(dev))
 274                 __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
 275 }
 276
 277 static void __swiotlb_sync_sg_for_cpu(struct device *dev,
 278                                       struct scatterlist *sgl, int nelems,
 279                                       enum dma_data_direction dir)
 280 {
 281         struct scatterlist *sg;
 282         int i;
 283
 284         if (!is_device_dma_coherent(dev))
 285                 for_each_sg(sgl, sg, nelems, i)
 286                         __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
 287                                          sg->length, dir);
 288         swiotlb_sync_sg_for_cpu(dev, sgl, nelems, dir);
 289 }
 290
 291 static void __swiotlb_sync_sg_for_device(struct device *dev,
 292                                          struct scatterlist *sgl, int nelems,
 293                                          enum dma_data_direction dir)
 294 {
 295         struct scatterlist *sg;
 296         int i;
 297
 298         swiotlb_sync_sg_for_device(dev, sgl, nelems, dir);
 299         if (!is_device_dma_coherent(dev))
 300                 for_each_sg(sgl, sg, nelems, i)
 301                         __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
 302                                        sg->length, dir);
 303 }
 304
 305 static int __swiotlb_mmap(struct device *dev,
 306                           struct vm_area_struct *vma,
 307                           void *cpu_addr, dma_addr_t dma_addr, size_t size,
 308                           struct dma_attrs *attrs)
 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         vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
 318                                              is_device_dma_coherent(dev));
 319
 320         if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
 321                 return ret;
 322
 323         if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
 324                 ret = remap_pfn_range(vma, vma->vm_start,
 325                                       pfn + off,
 326                                       vma->vm_end - vma->vm_start,
 327                                       vma->vm_page_prot);
 328         }
 329
 330         return ret;
 331 }
 332
 333 static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt,
 334                                  void *cpu_addr, dma_addr_t handle, size_t size,
 335                                  struct dma_attrs *attrs)
 336 {
 337         int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
 338
 339         if (!ret)
 340                 sg_set_page(sgt->sgl, phys_to_page(dma_to_phys(dev, handle)),
 341                             PAGE_ALIGN(size), 0);
 342
 343         return ret;
 344 }
 345
 346 static struct dma_map_ops swiotlb_dma_ops = {
 347         .alloc = __dma_alloc,
 348         .free = __dma_free,
 349         .mmap = __swiotlb_mmap,
 350         .get_sgtable = __swiotlb_get_sgtable,
 351         .map_page = __swiotlb_map_page,
 352         .unmap_page = __swiotlb_unmap_page,
 353         .map_sg = __swiotlb_map_sg_attrs,
 354         .unmap_sg = __swiotlb_unmap_sg_attrs,
 355         .sync_single_for_cpu = __swiotlb_sync_single_for_cpu,
 356         .sync_single_for_device = __swiotlb_sync_single_for_device,
 357         .sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu,
 358         .sync_sg_for_device = __swiotlb_sync_sg_for_device,
 359         .dma_supported = swiotlb_dma_supported,
 360         .mapping_error = swiotlb_dma_mapping_error,
 361 };
 362
 363 static int __init atomic_pool_init(void)
 364 {
 365         pgprot_t prot = __pgprot(PROT_NORMAL_NC);
 366         unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
 367         struct page *page;
 368         void *addr;
 369         unsigned int pool_size_order = get_order(atomic_pool_size);
 370
 371         if (dev_get_cma_area(NULL))
 372                 page = dma_alloc_from_contiguous(NULL, nr_pages,
 373                                                         pool_size_order);
 374         else
 375                 page = alloc_pages(GFP_DMA, pool_size_order);
 376
 377         if (page) {
 378                 int ret;
 379                 void *page_addr = page_address(page);
 380
 381                 memset(page_addr, 0, atomic_pool_size);
 382                 __dma_flush_range(page_addr, page_addr + atomic_pool_size);
 383
 384                 atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
 385                 if (!atomic_pool)
 386                         goto free_page;
 387
 388                 addr = dma_common_contiguous_remap(page, atomic_pool_size,
 389                                         VM_USERMAP, prot, atomic_pool_init);
 390
 391                 if (!addr)
 392                         goto destroy_genpool;
 393
 394                 ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
 395                                         page_to_phys(page),
 396                                         atomic_pool_size, -1);
 397                 if (ret)
 398                         goto remove_mapping;
 399
 400                 gen_pool_set_algo(atomic_pool,
 401                                   gen_pool_first_fit_order_align,
 402                                   (void *)PAGE_SHIFT);
 403
 404                 pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
 405                         atomic_pool_size / 1024);
 406                 return 0;
 407         }
 408         goto out;
 409
 410 remove_mapping:
 411         dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP);
 412 destroy_genpool:
 413         gen_pool_destroy(atomic_pool);
 414         atomic_pool = NULL;
 415 free_page:
 416         if (!dma_release_from_contiguous(NULL, page, nr_pages))
 417                 __free_pages(page, pool_size_order);
 418 out:
 419         pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
 420                 atomic_pool_size / 1024);
 421         return -ENOMEM;
 422 }
 423
 424 /********************************************
 425  * The following APIs are for dummy DMA ops *
 426  ********************************************/
 427
 428 static void *__dummy_alloc(struct device *dev, size_t size,
 429                            dma_addr_t *dma_handle, gfp_t flags,
 430                            struct dma_attrs *attrs)
 431 {
 432         return NULL;
 433 }
 434
 435 static void __dummy_free(struct device *dev, size_t size,
 436                          void *vaddr, dma_addr_t dma_handle,
 437                          struct dma_attrs *attrs)
 438 {
 439 }
 440
 441 static int __dummy_mmap(struct device *dev,
 442                         struct vm_area_struct *vma,
 443                         void *cpu_addr, dma_addr_t dma_addr, size_t size,
 444                         struct dma_attrs *attrs)
 445 {
 446         return -ENXIO;
 447 }
 448
 449 static dma_addr_t __dummy_map_page(struct device *dev, struct page *page,
 450                                    unsigned long offset, size_t size,
 451                                    enum dma_data_direction dir,
 452                                    struct dma_attrs *attrs)
 453 {
 454         return DMA_ERROR_CODE;
 455 }
 456
 457 static void __dummy_unmap_page(struct device *dev, dma_addr_t dev_addr,
 458                                size_t size, enum dma_data_direction dir,
 459                                struct dma_attrs *attrs)
 460 {
 461 }
 462
 463 static int __dummy_map_sg(struct device *dev, struct scatterlist *sgl,
 464                           int nelems, enum dma_data_direction dir,
 465                           struct dma_attrs *attrs)
 466 {
 467         return 0;
 468 }
 469
 470 static void __dummy_unmap_sg(struct device *dev,
 471                              struct scatterlist *sgl, int nelems,
 472                              enum dma_data_direction dir,
 473                              struct dma_attrs *attrs)
 474 {
 475 }
 476
 477 static void __dummy_sync_single(struct device *dev,
 478                                 dma_addr_t dev_addr, size_t size,
 479                                 enum dma_data_direction dir)
 480 {
 481 }
 482
 483 static void __dummy_sync_sg(struct device *dev,
 484                             struct scatterlist *sgl, int nelems,
 485                             enum dma_data_direction dir)
 486 {
 487 }
 488
 489 static int __dummy_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 490 {
 491         return 1;
 492 }
 493
 494 static int __dummy_dma_supported(struct device *hwdev, u64 mask)
 495 {
 496         return 0;
 497 }
 498
 499 struct dma_map_ops dummy_dma_ops = {
 500         .alloc                  = __dummy_alloc,
 501         .free                   = __dummy_free,
 502         .mmap                   = __dummy_mmap,
 503         .map_page               = __dummy_map_page,
 504         .unmap_page             = __dummy_unmap_page,
 505         .map_sg                 = __dummy_map_sg,
 506         .unmap_sg               = __dummy_unmap_sg,
 507         .sync_single_for_cpu    = __dummy_sync_single,
 508         .sync_single_for_device = __dummy_sync_single,
 509         .sync_sg_for_cpu        = __dummy_sync_sg,
 510         .sync_sg_for_device     = __dummy_sync_sg,
 511         .mapping_error          = __dummy_mapping_error,
 512         .dma_supported          = __dummy_dma_supported,
 513 };
 514 EXPORT_SYMBOL(dummy_dma_ops);
 515
 516 static int __init arm64_dma_init(void)
 517 {
 518         int ret;
 519
 520         dma_ops = &swiotlb_dma_ops;
 521
 522         ret = atomic_pool_init();
 523
 524         return ret;
 525 }
 526 arch_initcall(arm64_dma_init);
 527
 528 #define PREALLOC_DMA_DEBUG_ENTRIES      4096
 529
 530 static int __init dma_debug_do_init(void)
 531 {
 532         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 533         return 0;
 534 }
 535 fs_initcall(dma_debug_do_init);
 536
 537
 538 #ifdef CONFIG_IOMMU_DMA
 539 #include <linux/dma-iommu.h>
 540 #include <linux/platform_device.h>
 541 #include <linux/amba/bus.h>
 542
 543 /* Thankfully, all cache ops are by VA so we can ignore phys here */
 544 static void flush_page(struct device *dev, const void *virt, phys_addr_t phys)
 545 {
 546         __dma_flush_range(virt, virt + PAGE_SIZE);
 547 }
 548
 549 static void *__iommu_alloc_attrs(struct device *dev, size_t size,
 550                                  dma_addr_t *handle, gfp_t gfp,
 551                                  struct dma_attrs *attrs)
 552 {
 553         bool coherent = is_device_dma_coherent(dev);
 554         int ioprot = dma_direction_to_prot(DMA_BIDIRECTIONAL, coherent);
 555         size_t iosize = size;
 556         void *addr;
 557
 558         if (WARN(!dev, "cannot create IOMMU mapping for unknown device\n"))
 559                 return NULL;
 560
 561         size = PAGE_ALIGN(size);
 562
 563         /*
 564          * Some drivers rely on this, and we probably don't want the
 565          * possibility of stale kernel data being read by devices anyway.
 566          */
 567         gfp |= __GFP_ZERO;
 568
 569         if (gfpflags_allow_blocking(gfp)) {
 570                 struct page **pages;
 571                 pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, coherent);
 572
 573                 pages = iommu_dma_alloc(dev, iosize, gfp, ioprot, handle,
 574                                         flush_page);
 575                 if (!pages)
 576                         return NULL;
 577
 578                 addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
 579                                               __builtin_return_address(0));
 580                 if (!addr)
 581                         iommu_dma_free(dev, pages, iosize, handle);
 582         } else {
 583                 struct page *page;
 584                 /*
 585                  * In atomic context we can't remap anything, so we'll only
 586                  * get the virtually contiguous buffer we need by way of a
 587                  * physically contiguous allocation.
 588                  */
 589                 if (coherent) {
 590                         page = alloc_pages(gfp, get_order(size));
 591                         addr = page ? page_address(page) : NULL;
 592                 } else {
 593                         addr = __alloc_from_pool(size, &page, gfp);
 594                 }
 595                 if (!addr)
 596                         return NULL;
 597
 598                 *handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
 599                 if (iommu_dma_mapping_error(dev, *handle)) {
 600                         if (coherent)
 601                                 __free_pages(page, get_order(size));
 602                         else
 603                                 __free_from_pool(addr, size);
 604                         addr = NULL;
 605                 }
 606         }
 607         return addr;
 608 }
 609
 610 static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 611                                dma_addr_t handle, struct dma_attrs *attrs)
 612 {
 613         size_t iosize = size;
 614
 615         size = PAGE_ALIGN(size);
 616         /*
 617          * @cpu_addr will be one of 3 things depending on how it was allocated:
 618          * - A remapped array of pages from iommu_dma_alloc(), for all
 619          *   non-atomic allocations.
 620          * - A non-cacheable alias from the atomic pool, for atomic
 621          *   allocations by non-coherent devices.
 622          * - A normal lowmem address, for atomic allocations by
 623          *   coherent devices.
 624          * Hence how dodgy the below logic looks...
 625          */
 626         if (__in_atomic_pool(cpu_addr, size)) {
 627                 iommu_dma_unmap_page(dev, handle, iosize, 0, NULL);
 628                 __free_from_pool(cpu_addr, size);
 629         } else if (is_vmalloc_addr(cpu_addr)){
 630                 struct vm_struct *area = find_vm_area(cpu_addr);
 631
 632                 if (WARN_ON(!area || !area->pages))
 633                         return;
 634                 iommu_dma_free(dev, area->pages, iosize, &handle);
 635                 dma_common_free_remap(cpu_addr, size, VM_USERMAP);
 636         } else {
 637                 iommu_dma_unmap_page(dev, handle, iosize, 0, NULL);
 638                 __free_pages(virt_to_page(cpu_addr), get_order(size));
 639         }
 640 }
 641
 642 static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 643                               void *cpu_addr, dma_addr_t dma_addr, size_t size,
 644                               struct dma_attrs *attrs)
 645 {
 646         struct vm_struct *area;
 647         int ret;
 648
 649         vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
 650                                              is_device_dma_coherent(dev));
 651
 652         if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
 653                 return ret;
 654
 655         area = find_vm_area(cpu_addr);
 656         if (WARN_ON(!area || !area->pages))
 657                 return -ENXIO;
 658
 659         return iommu_dma_mmap(area->pages, size, vma);
 660 }
 661
 662 static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
 663                                void *cpu_addr, dma_addr_t dma_addr,
 664                                size_t size, struct dma_attrs *attrs)
 665 {
 666         unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 667         struct vm_struct *area = find_vm_area(cpu_addr);
 668
 669         if (WARN_ON(!area || !area->pages))
 670                 return -ENXIO;
 671
 672         return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
 673                                          GFP_KERNEL);
 674 }
 675
 676 static void __iommu_sync_single_for_cpu(struct device *dev,
 677                                         dma_addr_t dev_addr, size_t size,
 678                                         enum dma_data_direction dir)
 679 {
 680         phys_addr_t phys;
 681
 682         if (is_device_dma_coherent(dev))
 683                 return;
 684
 685         phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
 686         __dma_unmap_area(phys_to_virt(phys), size, dir);
 687 }
 688
 689 static void __iommu_sync_single_for_device(struct device *dev,
 690                                            dma_addr_t dev_addr, size_t size,
 691                                            enum dma_data_direction dir)
 692 {
 693         phys_addr_t phys;
 694
 695         if (is_device_dma_coherent(dev))
 696                 return;
 697
 698         phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
 699         __dma_map_area(phys_to_virt(phys), size, dir);
 700 }
 701
 702 static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
 703                                    unsigned long offset, size_t size,
 704                                    enum dma_data_direction dir,
 705                                    struct dma_attrs *attrs)
 706 {
 707         bool coherent = is_device_dma_coherent(dev);
 708         int prot = dma_direction_to_prot(dir, coherent);
 709         dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
 710
 711         if (!iommu_dma_mapping_error(dev, dev_addr) &&
 712             !dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
 713                 __iommu_sync_single_for_device(dev, dev_addr, size, dir);
 714
 715         return dev_addr;
 716 }
 717
 718 static void __iommu_unmap_page(struct device *dev, dma_addr_t dev_addr,
 719                                size_t size, enum dma_data_direction dir,
 720                                struct dma_attrs *attrs)
 721 {
 722         if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
 723                 __iommu_sync_single_for_cpu(dev, dev_addr, size, dir);
 724
 725         iommu_dma_unmap_page(dev, dev_addr, size, dir, attrs);
 726 }
 727
 728 static void __iommu_sync_sg_for_cpu(struct device *dev,
 729                                     struct scatterlist *sgl, int nelems,
 730                                     enum dma_data_direction dir)
 731 {
 732         struct scatterlist *sg;
 733         int i;
 734
 735         if (is_device_dma_coherent(dev))
 736                 return;
 737
 738         for_each_sg(sgl, sg, nelems, i)
 739                 __dma_unmap_area(sg_virt(sg), sg->length, dir);
 740 }
 741
 742 static void __iommu_sync_sg_for_device(struct device *dev,
 743                                        struct scatterlist *sgl, int nelems,
 744                                        enum dma_data_direction dir)
 745 {
 746         struct scatterlist *sg;
 747         int i;
 748
 749         if (is_device_dma_coherent(dev))
 750                 return;
 751
 752         for_each_sg(sgl, sg, nelems, i)
 753                 __dma_map_area(sg_virt(sg), sg->length, dir);
 754 }
 755
 756 static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
 757                                 int nelems, enum dma_data_direction dir,
 758                                 struct dma_attrs *attrs)
 759 {
 760         bool coherent = is_device_dma_coherent(dev);
 761
 762         if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
 763                 __iommu_sync_sg_for_device(dev, sgl, nelems, dir);
 764
 765         return iommu_dma_map_sg(dev, sgl, nelems,
 766                         dma_direction_to_prot(dir, coherent));
 767 }
 768
 769 static void __iommu_unmap_sg_attrs(struct device *dev,
 770                                    struct scatterlist *sgl, int nelems,
 771                                    enum dma_data_direction dir,
 772                                    struct dma_attrs *attrs)
 773 {
 774         if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
 775                 __iommu_sync_sg_for_cpu(dev, sgl, nelems, dir);
 776
 777         iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs);
 778 }
 779
 780 static struct dma_map_ops iommu_dma_ops = {
 781         .alloc = __iommu_alloc_attrs,
 782         .free = __iommu_free_attrs,
 783         .mmap = __iommu_mmap_attrs,
 784         .get_sgtable = __iommu_get_sgtable,
 785         .map_page = __iommu_map_page,
 786         .unmap_page = __iommu_unmap_page,
 787         .map_sg = __iommu_map_sg_attrs,
 788         .unmap_sg = __iommu_unmap_sg_attrs,
 789         .sync_single_for_cpu = __iommu_sync_single_for_cpu,
 790         .sync_single_for_device = __iommu_sync_single_for_device,
 791         .sync_sg_for_cpu = __iommu_sync_sg_for_cpu,
 792         .sync_sg_for_device = __iommu_sync_sg_for_device,
 793         .dma_supported = iommu_dma_supported,
 794         .mapping_error = iommu_dma_mapping_error,
 795 };
 796
 797 /*
 798  * TODO: Right now __iommu_setup_dma_ops() gets called too early to do
 799  * everything it needs to - the device is only partially created and the
 800  * IOMMU driver hasn't seen it yet, so it can't have a group. Thus we
 801  * need this delayed attachment dance. Once IOMMU probe ordering is sorted
 802  * to move the arch_setup_dma_ops() call later, all the notifier bits below
 803  * become unnecessary, and will go away.
 804  */
 805 struct iommu_dma_notifier_data {
 806         struct list_head list;
 807         struct device *dev;
 808         const struct iommu_ops *ops;
 809         u64 dma_base;
 810         u64 size;
 811 };
 812 static LIST_HEAD(iommu_dma_masters);
 813 static DEFINE_MUTEX(iommu_dma_notifier_lock);
 814
 815 /*
 816  * Temporarily "borrow" a domain feature flag to to tell if we had to resort
 817  * to creating our own domain here, in case we need to clean it up again.
 818  */
 819 #define __IOMMU_DOMAIN_FAKE_DEFAULT             (1U << 31)
 820
 821 static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops,
 822                            u64 dma_base, u64 size)
 823 {
 824         struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 825
 826         /*
 827          * Best case: The device is either part of a group which was
 828          * already attached to a domain in a previous call, or it's
 829          * been put in a default DMA domain by the IOMMU core.
 830          */
 831         if (!domain) {
 832                 /*
 833                  * Urgh. The IOMMU core isn't going to do default domains
 834                  * for non-PCI devices anyway, until it has some means of
 835                  * abstracting the entirely implementation-specific
 836                  * sideband data/SoC topology/unicorn dust that may or
 837                  * may not differentiate upstream masters.
 838                  * So until then, HORRIBLE HACKS!
 839                  */
 840                 domain = ops->domain_alloc(IOMMU_DOMAIN_DMA);
 841                 if (!domain)
 842                         goto out_no_domain;
 843
 844                 domain->ops = ops;
 845                 domain->type = IOMMU_DOMAIN_DMA | __IOMMU_DOMAIN_FAKE_DEFAULT;
 846
 847                 if (iommu_attach_device(domain, dev))
 848                         goto out_put_domain;
 849         }
 850
 851         if (iommu_dma_init_domain(domain, dma_base, size))
 852                 goto out_detach;
 853
 854         dev->archdata.dma_ops = &iommu_dma_ops;
 855         return true;
 856
 857 out_detach:
 858         iommu_detach_device(domain, dev);
 859 out_put_domain:
 860         if (domain->type & __IOMMU_DOMAIN_FAKE_DEFAULT)
 861                 iommu_domain_free(domain);
 862 out_no_domain:
 863         pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
 864                 dev_name(dev));
 865         return false;
 866 }
 867
 868 static void queue_iommu_attach(struct device *dev, const struct iommu_ops *ops,
 869                               u64 dma_base, u64 size)
 870 {
 871         struct iommu_dma_notifier_data *iommudata;
 872
 873         iommudata = kzalloc(sizeof(*iommudata), GFP_KERNEL);
 874         if (!iommudata)
 875                 return;
 876
 877         iommudata->dev = dev;
 878         iommudata->ops = ops;
 879         iommudata->dma_base = dma_base;
 880         iommudata->size = size;
 881
 882         mutex_lock(&iommu_dma_notifier_lock);
 883         list_add(&iommudata->list, &iommu_dma_masters);
 884         mutex_unlock(&iommu_dma_notifier_lock);
 885 }
 886
 887 static int __iommu_attach_notifier(struct notifier_block *nb,
 888                                    unsigned long action, void *data)
 889 {
 890         struct iommu_dma_notifier_data *master, *tmp;
 891
 892         if (action != BUS_NOTIFY_ADD_DEVICE)
 893                 return 0;
 894
 895         mutex_lock(&iommu_dma_notifier_lock);
 896         list_for_each_entry_safe(master, tmp, &iommu_dma_masters, list) {
 897                 if (do_iommu_attach(master->dev, master->ops,
 898                                 master->dma_base, master->size)) {
 899                         list_del(&master->list);
 900                         kfree(master);
 901                 }
 902         }
 903         mutex_unlock(&iommu_dma_notifier_lock);
 904         return 0;
 905 }
 906
 907 static int register_iommu_dma_ops_notifier(struct bus_type *bus)
 908 {
 909         struct notifier_block *nb = kzalloc(sizeof(*nb), GFP_KERNEL);
 910         int ret;
 911
 912         if (!nb)
 913                 return -ENOMEM;
 914         /*
 915          * The device must be attached to a domain before the driver probe
 916          * routine gets a chance to start allocating DMA buffers. However,
 917          * the IOMMU driver also needs a chance to configure the iommu_group
 918          * via its add_device callback first, so we need to make the attach
 919          * happen between those two points. Since the IOMMU core uses a bus
 920          * notifier with default priority for add_device, do the same but
 921          * with a lower priority to ensure the appropriate ordering.
 922          */
 923         nb->notifier_call = __iommu_attach_notifier;
 924         nb->priority = -100;
 925
 926         ret = bus_register_notifier(bus, nb);
 927         if (ret) {
 928                 pr_warn("Failed to register DMA domain notifier; IOMMU DMA ops unavailable on bus '%s'\n",
 929                         bus->name);
 930                 kfree(nb);
 931         }
 932         return ret;
 933 }
 934
 935 static int __init __iommu_dma_init(void)
 936 {
 937         int ret;
 938
 939         ret = iommu_dma_init();
 940         if (!ret)
 941                 ret = register_iommu_dma_ops_notifier(&platform_bus_type);
 942         if (!ret)
 943                 ret = register_iommu_dma_ops_notifier(&amba_bustype);
 944         return ret;
 945 }
 946 arch_initcall(__iommu_dma_init);
 947
 948 static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 949                                   const struct iommu_ops *ops)
 950 {
 951         struct iommu_group *group;
 952
 953         if (!ops)
 954                 return;
 955         /*
 956          * TODO: As a concession to the future, we're ready to handle being
 957          * called both early and late (i.e. after bus_add_device). Once all
 958          * the platform bus code is reworked to call us late and the notifier
 959          * junk above goes away, move the body of do_iommu_attach here.
 960          */
 961         group = iommu_group_get(dev);
 962         if (group) {
 963                 do_iommu_attach(dev, ops, dma_base, size);
 964                 iommu_group_put(group);
 965         } else {
 966                 queue_iommu_attach(dev, ops, dma_base, size);
 967         }
 968 }
 969
 970 void arch_teardown_dma_ops(struct device *dev)
 971 {
 972         struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 973
 974         if (domain) {
 975                 iommu_detach_device(domain, dev);
 976                 if (domain->type & __IOMMU_DOMAIN_FAKE_DEFAULT)
 977                         iommu_domain_free(domain);
 978         }
 979
 980         dev->archdata.dma_ops = NULL;
 981 }
 982
 983 #else
 984
 985 static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 986                                   struct iommu_ops *iommu)
 987 { }
 988
 989 #endif  /* CONFIG_IOMMU_DMA */
 990
 991 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 992                         struct iommu_ops *iommu, bool coherent)
 993 {
 994         if (!acpi_disabled && !dev->archdata.dma_ops)
 995                 dev->archdata.dma_ops = dma_ops;
 996
 997         dev->archdata.dma_coherent = coherent;
 998         __iommu_setup_dma_ops(dev, dma_base, size, iommu);
 999 }