linux-core/drm_bo_move.c

   1 /**************************************************************************
   2  *
   3  * Copyright (c) 2007 Tungsten Graphics, Inc., Cedar Park, TX., USA
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27 /*
  28  * Authors: Thomas Hellström <thomas-at-tungstengraphics-dot-com>
  29  */
  30
  31 #include "drmP.h"
  32
  33 /**
  34  * Free the old memory node unless it's a pinned region and we
  35  * have not been requested to free also pinned regions.
  36  */
  37
  38 static void drm_bo_free_old_node(struct drm_buffer_object *bo)
  39 {
  40         struct drm_bo_mem_reg *old_mem = &bo->mem;
  41
  42         if (old_mem->mm_node && (old_mem->mm_node != bo->pinned_node)) {
  43                 mutex_lock(&bo->dev->struct_mutex);
  44                 drm_mm_put_block(old_mem->mm_node);
  45                 mutex_unlock(&bo->dev->struct_mutex);
  46         }
  47         old_mem->mm_node = NULL;
  48 }
  49
  50 int drm_bo_move_ttm(struct drm_buffer_object *bo,
  51                     int evict, int no_wait, struct drm_bo_mem_reg *new_mem)
  52 {
  53         struct drm_ttm *ttm = bo->ttm;
  54         struct drm_bo_mem_reg *old_mem = &bo->mem;
  55         uint64_t save_flags = old_mem->flags;
  56         uint64_t save_proposed_flags = old_mem->proposed_flags;
  57         int ret;
  58
  59         if (old_mem->mem_type != DRM_BO_MEM_LOCAL) {
  60                 if (evict)
  61                         drm_ttm_evict(ttm);
  62                 else
  63                         drm_ttm_unbind(ttm);
  64
  65                 drm_bo_free_old_node(bo);
  66                 DRM_FLAG_MASKED(old_mem->flags,
  67                                 DRM_BO_FLAG_CACHED | DRM_BO_FLAG_MAPPABLE |
  68                                 DRM_BO_FLAG_MEM_LOCAL, DRM_BO_MASK_MEMTYPE);
  69                 old_mem->mem_type = DRM_BO_MEM_LOCAL;
  70                 save_flags = old_mem->flags;
  71         }
  72         if (new_mem->mem_type != DRM_BO_MEM_LOCAL) {
  73                 ret = drm_ttm_bind(ttm, new_mem);
  74                 if (ret)
  75                         return ret;
  76         }
  77
  78         *old_mem = *new_mem;
  79         new_mem->mm_node = NULL;
  80         old_mem->proposed_flags = save_proposed_flags;
  81         DRM_FLAG_MASKED(save_flags, new_mem->flags, DRM_BO_MASK_MEMTYPE);
  82         return 0;
  83 }
  84 EXPORT_SYMBOL(drm_bo_move_ttm);
  85
  86 /**
  87  * \c Return a kernel virtual address to the buffer object PCI memory.
  88  *
  89  * \param bo The buffer object.
  90  * \return Failure indication.
  91  *
  92  * Returns -EINVAL if the buffer object is currently not mappable.
  93  * Returns -ENOMEM if the ioremap operation failed.
  94  * Otherwise returns zero.
  95  *
  96  * After a successfull call, bo->iomap contains the virtual address, or NULL
  97  * if the buffer object content is not accessible through PCI space.
  98  * Call bo->mutex locked.
  99  */
 100
 101 int drm_mem_reg_ioremap(struct drm_device *dev, struct drm_bo_mem_reg *mem,
 102                         void **virtual)
 103 {
 104         struct drm_buffer_manager *bm = &dev->bm;
 105         struct drm_mem_type_manager *man = &bm->man[mem->mem_type];
 106         unsigned long bus_offset;
 107         unsigned long bus_size;
 108         unsigned long bus_base;
 109         int ret;
 110         void *addr;
 111
 112         *virtual = NULL;
 113         ret = drm_bo_pci_offset(dev, mem, &bus_base, &bus_offset, &bus_size);
 114         if (ret || bus_size == 0)
 115                 return ret;
 116
 117         if (!(man->flags & _DRM_FLAG_NEEDS_IOREMAP))
 118                 addr = (void *)(((u8 *) man->io_addr) + bus_offset);
 119         else {
 120                 addr = ioremap_nocache(bus_base + bus_offset, bus_size);
 121                 if (!addr)
 122                         return -ENOMEM;
 123         }
 124         *virtual = addr;
 125         return 0;
 126 }
 127 EXPORT_SYMBOL(drm_mem_reg_ioremap);
 128
 129 /**
 130  * \c Unmap mapping obtained using drm_bo_ioremap
 131  *
 132  * \param bo The buffer object.
 133  *
 134  * Call bo->mutex locked.
 135  */
 136
 137 void drm_mem_reg_iounmap(struct drm_device *dev, struct drm_bo_mem_reg *mem,
 138                          void *virtual)
 139 {
 140         struct drm_buffer_manager *bm;
 141         struct drm_mem_type_manager *man;
 142
 143         bm = &dev->bm;
 144         man = &bm->man[mem->mem_type];
 145
 146         if (virtual && (man->flags & _DRM_FLAG_NEEDS_IOREMAP))
 147                 iounmap(virtual);
 148 }
 149 EXPORT_SYMBOL(drm_mem_reg_iounmap);
 150
 151 static int drm_copy_io_page(void *dst, void *src, unsigned long page)
 152 {
 153         uint32_t *dstP =
 154             (uint32_t *) ((unsigned long)dst + (page << PAGE_SHIFT));
 155         uint32_t *srcP =
 156             (uint32_t *) ((unsigned long)src + (page << PAGE_SHIFT));
 157
 158         int i;
 159         for (i = 0; i < PAGE_SIZE / sizeof(uint32_t); ++i)
 160                 iowrite32(ioread32(srcP++), dstP++);
 161         return 0;
 162 }
 163
 164 static int drm_copy_io_ttm_page(struct drm_ttm *ttm, void *src,
 165                                 unsigned long page)
 166 {
 167         struct page *d = drm_ttm_get_page(ttm, page);
 168         void *dst;
 169
 170         if (!d)
 171                 return -ENOMEM;
 172
 173         src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
 174         dst = kmap(d);
 175         if (!dst)
 176                 return -ENOMEM;
 177
 178         memcpy_fromio(dst, src, PAGE_SIZE);
 179         kunmap(d);
 180         return 0;
 181 }
 182
 183 static int drm_copy_ttm_io_page(struct drm_ttm *ttm, void *dst, unsigned long page)
 184 {
 185         struct page *s = drm_ttm_get_page(ttm, page);
 186         void *src;
 187
 188         if (!s)
 189                 return -ENOMEM;
 190
 191         dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
 192         src = kmap(s);
 193         if (!src)
 194                 return -ENOMEM;
 195
 196         memcpy_toio(dst, src, PAGE_SIZE);
 197         kunmap(s);
 198         return 0;
 199 }
 200
 201 int drm_bo_move_memcpy(struct drm_buffer_object *bo,
 202                        int evict, int no_wait, struct drm_bo_mem_reg *new_mem)
 203 {
 204         struct drm_device *dev = bo->dev;
 205         struct drm_mem_type_manager *man = &dev->bm.man[new_mem->mem_type];
 206         struct drm_ttm *ttm = bo->ttm;
 207         struct drm_bo_mem_reg *old_mem = &bo->mem;
 208         struct drm_bo_mem_reg old_copy = *old_mem;
 209         void *old_iomap;
 210         void *new_iomap;
 211         int ret;
 212         uint64_t save_flags = old_mem->flags;
 213         uint64_t save_proposed_flags = old_mem->proposed_flags;
 214         unsigned long i;
 215         unsigned long page;
 216         unsigned long add = 0;
 217         int dir;
 218
 219         ret = drm_mem_reg_ioremap(dev, old_mem, &old_iomap);
 220         if (ret)
 221                 return ret;
 222         ret = drm_mem_reg_ioremap(dev, new_mem, &new_iomap);
 223         if (ret)
 224                 goto out;
 225
 226         if (old_iomap == NULL && new_iomap == NULL)
 227                 goto out2;
 228         if (old_iomap == NULL && ttm == NULL)
 229                 goto out2;
 230
 231         add = 0;
 232         dir = 1;
 233
 234         if ((old_mem->mem_type == new_mem->mem_type) &&
 235             (new_mem->mm_node->start <
 236              old_mem->mm_node->start + old_mem->mm_node->size)) {
 237                 dir = -1;
 238                 add = new_mem->num_pages - 1;
 239         }
 240
 241         for (i = 0; i < new_mem->num_pages; ++i) {
 242                 page = i * dir + add;
 243                 if (old_iomap == NULL)
 244                         ret = drm_copy_ttm_io_page(ttm, new_iomap, page);
 245                 else if (new_iomap == NULL)
 246                         ret = drm_copy_io_ttm_page(ttm, old_iomap, page);
 247                 else
 248                         ret = drm_copy_io_page(new_iomap, old_iomap, page);
 249                 if (ret)
 250                         goto out1;
 251         }
 252         mb();
 253 out2:
 254         drm_bo_free_old_node(bo);
 255
 256         *old_mem = *new_mem;
 257         new_mem->mm_node = NULL;
 258         old_mem->proposed_flags = save_proposed_flags;
 259         DRM_FLAG_MASKED(save_flags, new_mem->flags, DRM_BO_MASK_MEMTYPE);
 260
 261         if ((man->flags & _DRM_FLAG_MEMTYPE_FIXED) && (ttm != NULL)) {
 262                 drm_ttm_unbind(ttm);
 263                 drm_ttm_destroy(ttm);
 264                 bo->ttm = NULL;
 265         }
 266
 267 out1:
 268         drm_mem_reg_iounmap(dev, new_mem, new_iomap);
 269 out:
 270         drm_mem_reg_iounmap(dev, &old_copy, old_iomap);
 271         return ret;
 272 }
 273 EXPORT_SYMBOL(drm_bo_move_memcpy);
 274
 275 /*
 276  * Transfer a buffer object's memory and LRU status to a newly
 277  * created object. User-space references remains with the old
 278  * object. Call bo->mutex locked.
 279  */
 280
 281 int drm_buffer_object_transfer(struct drm_buffer_object *bo,
 282                                struct drm_buffer_object **new_obj)
 283 {
 284         struct drm_buffer_object *fbo;
 285         struct drm_device *dev = bo->dev;
 286         struct drm_buffer_manager *bm = &dev->bm;
 287
 288         fbo = drm_ctl_calloc(1, sizeof(*fbo), DRM_MEM_BUFOBJ);
 289         if (!fbo)
 290                 return -ENOMEM;
 291
 292         *fbo = *bo;
 293         mutex_init(&fbo->mutex);
 294         mutex_lock(&fbo->mutex);
 295         mutex_lock(&dev->struct_mutex);
 296
 297         DRM_INIT_WAITQUEUE(&bo->event_queue);
 298         INIT_LIST_HEAD(&fbo->ddestroy);
 299         INIT_LIST_HEAD(&fbo->lru);
 300         INIT_LIST_HEAD(&fbo->pinned_lru);
 301 #ifdef DRM_ODD_MM_COMPAT
 302         INIT_LIST_HEAD(&fbo->vma_list);
 303         INIT_LIST_HEAD(&fbo->p_mm_list);
 304 #endif
 305
 306         fbo->fence = drm_fence_reference_locked(bo->fence);
 307         fbo->pinned_node = NULL;
 308         fbo->mem.mm_node->private = (void *)fbo;
 309         atomic_set(&fbo->usage, 1);
 310         atomic_inc(&bm->count);
 311         mutex_unlock(&dev->struct_mutex);
 312         mutex_unlock(&fbo->mutex);
 313
 314         *new_obj = fbo;
 315         return 0;
 316 }
 317
 318 /*
 319  * Since move is underway, we need to block signals in this function.
 320  * We cannot restart until it has finished.
 321  */
 322
 323 int drm_bo_move_accel_cleanup(struct drm_buffer_object *bo,
 324                               int evict, int no_wait, uint32_t fence_class,
 325                               uint32_t fence_type, uint32_t fence_flags,
 326                               struct drm_bo_mem_reg *new_mem)
 327 {
 328         struct drm_device *dev = bo->dev;
 329         struct drm_mem_type_manager *man = &dev->bm.man[new_mem->mem_type];
 330         struct drm_bo_mem_reg *old_mem = &bo->mem;
 331         int ret;
 332         uint64_t save_flags = old_mem->flags;
 333         uint64_t save_proposed_flags = old_mem->proposed_flags;
 334         struct drm_buffer_object *old_obj;
 335
 336         if (bo->fence)
 337                 drm_fence_usage_deref_unlocked(&bo->fence);
 338         ret = drm_fence_object_create(dev, fence_class, fence_type,
 339                                       fence_flags | DRM_FENCE_FLAG_EMIT,
 340                                       &bo->fence);
 341         bo->fence_type = fence_type;
 342         if (ret)
 343                 return ret;
 344
 345 #ifdef DRM_ODD_MM_COMPAT
 346         /*
 347          * In this mode, we don't allow pipelining a copy blit,
 348          * since the buffer will be accessible from user space
 349          * the moment we return and rebuild the page tables.
 350          *
 351          * With normal vm operation, page tables are rebuilt
 352          * on demand using fault(), which waits for buffer idle.
 353          */
 354         if (1)
 355 #else
 356         if (evict || ((bo->mem.mm_node == bo->pinned_node) &&
 357                       bo->mem.mm_node != NULL))
 358 #endif
 359         {
 360                 if (bo->fence) {
 361                         (void) drm_fence_object_wait(bo->fence, 0, 1,
 362                                                     bo->fence_type);
 363                         drm_fence_usage_deref_unlocked(&bo->fence);
 364                 }
 365                 drm_bo_free_old_node(bo);
 366
 367                 if ((man->flags & _DRM_FLAG_MEMTYPE_FIXED) && (bo->ttm != NULL)) {
 368                         drm_ttm_unbind(bo->ttm);
 369                         drm_ttm_destroy(bo->ttm);
 370                         bo->ttm = NULL;
 371                 }
 372         } else {
 373
 374                 /* This should help pipeline ordinary buffer moves.
 375                  *
 376                  * Hang old buffer memory on a new buffer object,
 377                  * and leave it to be released when the GPU
 378                  * operation has completed.
 379                  */
 380
 381                 ret = drm_buffer_object_transfer(bo, &old_obj);
 382
 383                 if (ret)
 384                         return ret;
 385
 386                 if (!(man->flags & _DRM_FLAG_MEMTYPE_FIXED))
 387                         old_obj->ttm = NULL;
 388                 else
 389                         bo->ttm = NULL;
 390
 391                 mutex_lock(&dev->struct_mutex);
 392                 list_del_init(&old_obj->lru);
 393                 DRM_FLAG_MASKED(bo->priv_flags, 0, _DRM_BO_FLAG_UNFENCED);
 394                 drm_bo_add_to_lru(old_obj);
 395
 396                 drm_bo_usage_deref_locked(&old_obj);
 397                 mutex_unlock(&dev->struct_mutex);
 398
 399         }
 400
 401         *old_mem = *new_mem;
 402         new_mem->mm_node = NULL;
 403         old_mem->proposed_flags = save_proposed_flags;
 404         DRM_FLAG_MASKED(save_flags, new_mem->flags, DRM_BO_MASK_MEMTYPE);
 405         return 0;
 406 }
 407 EXPORT_SYMBOL(drm_bo_move_accel_cleanup);
 408
 409 int drm_bo_same_page(unsigned long offset,
 410                      unsigned long offset2)
 411 {
 412         return (offset & PAGE_MASK) == (offset2 & PAGE_MASK);
 413 }
 414 EXPORT_SYMBOL(drm_bo_same_page);
 415
 416 unsigned long drm_bo_offset_end(unsigned long offset,
 417                                 unsigned long end)
 418 {
 419         offset = (offset + PAGE_SIZE) & PAGE_MASK;
 420         return (end < offset) ? end : offset;
 421 }
 422 EXPORT_SYMBOL(drm_bo_offset_end);
 423
 424 static pgprot_t drm_kernel_io_prot(uint32_t map_type)
 425 {
 426         pgprot_t tmp = PAGE_KERNEL;
 427
 428 #if defined(__i386__) || defined(__x86_64__)
 429 #ifdef USE_PAT_WC
 430 #warning using pat
 431         if (drm_use_pat() && map_type == _DRM_TTM) {
 432                 pgprot_val(tmp) |= _PAGE_PAT;
 433                 return tmp;
 434         }
 435 #endif
 436         if (boot_cpu_data.x86 > 3 && map_type != _DRM_AGP) {
 437                 pgprot_val(tmp) |= _PAGE_PCD;
 438                 pgprot_val(tmp) &= ~_PAGE_PWT;
 439         }
 440 #elif defined(__powerpc__)
 441         pgprot_val(tmp) |= _PAGE_NO_CACHE;
 442         if (map_type == _DRM_REGISTERS)
 443                 pgprot_val(tmp) |= _PAGE_GUARDED;
 444 #endif
 445 #if defined(__ia64__)
 446         if (map_type == _DRM_TTM)
 447                 tmp = pgprot_writecombine(tmp);
 448         else
 449                 tmp = pgprot_noncached(tmp);
 450 #endif
 451         return tmp;
 452 }
 453
 454 static int drm_bo_ioremap(struct drm_buffer_object *bo, unsigned long bus_base,
 455                           unsigned long bus_offset, unsigned long bus_size,
 456                           struct drm_bo_kmap_obj *map)
 457 {
 458         struct drm_device *dev = bo->dev;
 459         struct drm_bo_mem_reg *mem = &bo->mem;
 460         struct drm_mem_type_manager *man = &dev->bm.man[mem->mem_type];
 461
 462         if (!(man->flags & _DRM_FLAG_NEEDS_IOREMAP)) {
 463                 map->bo_kmap_type = bo_map_premapped;
 464                 map->virtual = (void *)(((u8 *) man->io_addr) + bus_offset);
 465         } else {
 466                 map->bo_kmap_type = bo_map_iomap;
 467                 map->virtual = ioremap_nocache(bus_base + bus_offset, bus_size);
 468         }
 469         return (!map->virtual) ? -ENOMEM : 0;
 470 }
 471
 472 static int drm_bo_kmap_ttm(struct drm_buffer_object *bo,
 473                            unsigned long start_page, unsigned long num_pages,
 474                            struct drm_bo_kmap_obj *map)
 475 {
 476         struct drm_device *dev = bo->dev;
 477         struct drm_bo_mem_reg *mem = &bo->mem;
 478         struct drm_mem_type_manager *man = &dev->bm.man[mem->mem_type];
 479         pgprot_t prot;
 480         struct drm_ttm *ttm = bo->ttm;
 481         struct page *d;
 482         int i;
 483
 484         BUG_ON(!ttm);
 485
 486         if (num_pages == 1 && (mem->flags & DRM_BO_FLAG_CACHED)) {
 487
 488                 /*
 489                  * We're mapping a single page, and the desired
 490                  * page protection is consistent with the bo.
 491                  */
 492
 493                 map->bo_kmap_type = bo_map_kmap;
 494                 map->page = drm_ttm_get_page(ttm, start_page);
 495                 map->virtual = kmap(map->page);
 496         } else {
 497                 /*
 498                  * Populate the part we're mapping;
 499                  */
 500
 501                 for (i = start_page; i < start_page + num_pages; ++i) {
 502                         d = drm_ttm_get_page(ttm, i);
 503                         if (!d)
 504                                 return -ENOMEM;
 505                 }
 506
 507                 /*
 508                  * We need to use vmap to get the desired page protection
 509                  * or to make the buffer object look contigous.
 510                  */
 511
 512                 prot = (mem->flags & DRM_BO_FLAG_CACHED) ?
 513                         PAGE_KERNEL :
 514                         drm_kernel_io_prot(man->drm_bus_maptype);
 515                 map->bo_kmap_type = bo_map_vmap;
 516                 map->virtual = vmap(ttm->pages + start_page,
 517                                     num_pages, 0, prot);
 518         }
 519         return (!map->virtual) ? -ENOMEM : 0;
 520 }
 521
 522 /*
 523  * This function is to be used for kernel mapping of buffer objects.
 524  * It chooses the appropriate mapping method depending on the memory type
 525  * and caching policy the buffer currently has.
 526  * Mapping multiple pages or buffers that live in io memory is a bit slow and
 527  * consumes vmalloc space. Be restrictive with such mappings.
 528  * Mapping single pages usually returns the logical kernel address,
 529  * (which is fast)
 530  * BUG may use slower temporary mappings for high memory pages or
 531  * uncached / write-combined pages.
 532  *
 533  * The function fills in a drm_bo_kmap_obj which can be used to return the
 534  * kernel virtual address of the buffer.
 535  *
 536  * Code servicing a non-priviliged user request is only allowed to map one
 537  * page at a time. We might need to implement a better scheme to stop such
 538  * processes from consuming all vmalloc space.
 539  */
 540
 541 int drm_bo_kmap(struct drm_buffer_object *bo, unsigned long start_page,
 542                 unsigned long num_pages, struct drm_bo_kmap_obj *map)
 543 {
 544         int ret;
 545         unsigned long bus_base;
 546         unsigned long bus_offset;
 547         unsigned long bus_size;
 548
 549         map->virtual = NULL;
 550
 551         if (num_pages > bo->num_pages)
 552                 return -EINVAL;
 553         if (start_page > bo->num_pages)
 554                 return -EINVAL;
 555 #if 0
 556         if (num_pages > 1 && !DRM_SUSER(DRM_CURPROC))
 557                 return -EPERM;
 558 #endif
 559         ret = drm_bo_pci_offset(bo->dev, &bo->mem, &bus_base,
 560                                 &bus_offset, &bus_size);
 561
 562         if (ret)
 563                 return ret;
 564
 565         if (bus_size == 0) {
 566                 return drm_bo_kmap_ttm(bo, start_page, num_pages, map);
 567         } else {
 568                 bus_offset += start_page << PAGE_SHIFT;
 569                 bus_size = num_pages << PAGE_SHIFT;
 570                 return drm_bo_ioremap(bo, bus_base, bus_offset, bus_size, map);
 571         }
 572 }
 573 EXPORT_SYMBOL(drm_bo_kmap);
 574
 575 void drm_bo_kunmap(struct drm_bo_kmap_obj *map)
 576 {
 577         if (!map->virtual)
 578                 return;
 579
 580         switch (map->bo_kmap_type) {
 581         case bo_map_iomap:
 582                 iounmap(map->virtual);
 583                 break;
 584         case bo_map_vmap:
 585                 vunmap(map->virtual);
 586                 break;
 587         case bo_map_kmap:
 588                 kunmap(map->page);
 589                 break;
 590         case bo_map_premapped:
 591                 break;
 592         default:
 593                 BUG();
 594         }
 595         map->virtual = NULL;
 596         map->page = NULL;
 597 }
 598 EXPORT_SYMBOL(drm_bo_kunmap);
 599
 600 int drm_bo_pfn_prot(struct drm_buffer_object *bo,
 601                     unsigned long dst_offset,
 602                     unsigned long *pfn,
 603                     pgprot_t *prot)
 604 {
 605         struct drm_bo_mem_reg *mem = &bo->mem;
 606         struct drm_device *dev = bo->dev;
 607         unsigned long bus_offset;
 608         unsigned long bus_size;
 609         unsigned long bus_base;
 610         struct drm_mem_type_manager *man = &dev->bm.man[mem->mem_type];
 611         int ret;
 612
 613         ret = drm_bo_pci_offset(dev, mem, &bus_base, &bus_offset,
 614                                 &bus_size);
 615         if (ret)
 616                 return -EINVAL;
 617
 618         if (bus_size != 0)
 619                 *pfn = (bus_base + bus_offset + dst_offset) >> PAGE_SHIFT;
 620         else if (!bo->ttm)
 621                 return -EINVAL;
 622         else
 623                 *pfn = page_to_pfn(drm_ttm_get_page(bo->ttm, dst_offset >> PAGE_SHIFT));
 624
 625         *prot = (mem->flags & DRM_BO_FLAG_CACHED) ?
 626                 PAGE_KERNEL : drm_kernel_io_prot(man->drm_bus_maptype);
 627
 628         return 0;
 629 }
 630 EXPORT_SYMBOL(drm_bo_pfn_prot);
 631