drivers/gpu/drm/i915/i915_gem_stolen.c

   1 /*
   2  * Copyright © 2008-2012 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *    Chris Wilson <chris@chris-wilson.co.uk>
  26  *
  27  */
  28
  29 #include <drm/drmP.h>
  30 #include <drm/i915_drm.h>
  31 #include "i915_drv.h"
  32
  33 /*
  34  * The BIOS typically reserves some of the system's memory for the exclusive
  35  * use of the integrated graphics. This memory is no longer available for
  36  * use by the OS and so the user finds that his system has less memory
  37  * available than he put in. We refer to this memory as stolen.
  38  *
  39  * The BIOS will allocate its framebuffer from the stolen memory. Our
  40  * goal is try to reuse that object for our own fbcon which must always
  41  * be available for panics. Anything else we can reuse the stolen memory
  42  * for is a boon.
  43  */
  44
  45 int i915_gem_stolen_insert_node_in_range(struct drm_i915_private *dev_priv,
  46                                          struct drm_mm_node *node, u64 size,
  47                                          unsigned alignment, u64 start, u64 end)
  48 {
  49         int ret;
  50
  51         if (!drm_mm_initialized(&dev_priv->mm.stolen))
  52                 return -ENODEV;
  53
  54         mutex_lock(&dev_priv->mm.stolen_lock);
  55         ret = drm_mm_insert_node_in_range(&dev_priv->mm.stolen, node, size,
  56                                           alignment, start, end,
  57                                           DRM_MM_SEARCH_DEFAULT);
  58         mutex_unlock(&dev_priv->mm.stolen_lock);
  59
  60         return ret;
  61 }
  62
  63 int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv,
  64                                 struct drm_mm_node *node, u64 size,
  65                                 unsigned alignment)
  66 {
  67         return i915_gem_stolen_insert_node_in_range(dev_priv, node, size,
  68                                         alignment, 0,
  69                                         dev_priv->gtt.stolen_usable_size);
  70 }
  71
  72 void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
  73                                  struct drm_mm_node *node)
  74 {
  75         mutex_lock(&dev_priv->mm.stolen_lock);
  76         drm_mm_remove_node(node);
  77         mutex_unlock(&dev_priv->mm.stolen_lock);
  78 }
  79
  80 static unsigned long i915_stolen_to_physical(struct drm_device *dev)
  81 {
  82         struct drm_i915_private *dev_priv = dev->dev_private;
  83         struct resource *r;
  84         u32 base;
  85
  86         /* Almost universally we can find the Graphics Base of Stolen Memory
  87          * at offset 0x5c in the igfx configuration space. On a few (desktop)
  88          * machines this is also mirrored in the bridge device at different
  89          * locations, or in the MCHBAR. On gen2, the layout is again slightly
  90          * different with the Graphics Segment immediately following Top of
  91          * Memory (or Top of Usable DRAM). Note it appears that TOUD is only
  92          * reported by 865g, so we just use the top of memory as determined
  93          * by the e820 probe.
  94          *
  95          * XXX However gen2 requires an unavailable symbol.
  96          */
  97         base = 0;
  98         if (INTEL_INFO(dev)->gen >= 3) {
  99                 /* Read Graphics Base of Stolen Memory directly */
 100                 pci_read_config_dword(dev->pdev, 0x5c, &base);
 101                 base &= ~((1<<20) - 1);
 102         } else { /* GEN2 */
 103 #if 0
 104                 /* Stolen is immediately above Top of Memory */
 105                 base = max_low_pfn_mapped << PAGE_SHIFT;
 106 #endif
 107         }
 108
 109         if (base == 0)
 110                 return 0;
 111
 112         /* make sure we don't clobber the GTT if it's within stolen memory */
 113         if (INTEL_INFO(dev)->gen <= 4 && !IS_G33(dev) && !IS_G4X(dev)) {
 114                 struct {
 115                         u32 start, end;
 116                 } stolen[2] = {
 117                         { .start = base, .end = base + dev_priv->gtt.stolen_size, },
 118                         { .start = base, .end = base + dev_priv->gtt.stolen_size, },
 119                 };
 120                 u64 gtt_start, gtt_end;
 121
 122                 gtt_start = I915_READ(PGTBL_CTL);
 123                 if (IS_GEN4(dev))
 124                         gtt_start = (gtt_start & PGTBL_ADDRESS_LO_MASK) |
 125                                 (gtt_start & PGTBL_ADDRESS_HI_MASK) << 28;
 126                 else
 127                         gtt_start &= PGTBL_ADDRESS_LO_MASK;
 128                 gtt_end = gtt_start + gtt_total_entries(dev_priv->gtt) * 4;
 129
 130                 if (gtt_start >= stolen[0].start && gtt_start < stolen[0].end)
 131                         stolen[0].end = gtt_start;
 132                 if (gtt_end > stolen[1].start && gtt_end <= stolen[1].end)
 133                         stolen[1].start = gtt_end;
 134
 135                 /* pick the larger of the two chunks */
 136                 if (stolen[0].end - stolen[0].start >
 137                     stolen[1].end - stolen[1].start) {
 138                         base = stolen[0].start;
 139                         dev_priv->gtt.stolen_size = stolen[0].end - stolen[0].start;
 140                 } else {
 141                         base = stolen[1].start;
 142                         dev_priv->gtt.stolen_size = stolen[1].end - stolen[1].start;
 143                 }
 144
 145                 if (stolen[0].start != stolen[1].start ||
 146                     stolen[0].end != stolen[1].end) {
 147                         DRM_DEBUG_KMS("GTT within stolen memory at 0x%llx-0x%llx\n",
 148                                       (unsigned long long) gtt_start,
 149                                       (unsigned long long) gtt_end - 1);
 150                         DRM_DEBUG_KMS("Stolen memory adjusted to 0x%x-0x%x\n",
 151                                       base, base + (u32) dev_priv->gtt.stolen_size - 1);
 152                 }
 153         }
 154
 155
 156         /* Verify that nothing else uses this physical address. Stolen
 157          * memory should be reserved by the BIOS and hidden from the
 158          * kernel. So if the region is already marked as busy, something
 159          * is seriously wrong.
 160          */
 161         r = devm_request_mem_region(dev->dev, base, dev_priv->gtt.stolen_size,
 162                                     "Graphics Stolen Memory");
 163         if (r == NULL) {
 164                 /*
 165                  * One more attempt but this time requesting region from
 166                  * base + 1, as we have seen that this resolves the region
 167                  * conflict with the PCI Bus.
 168                  * This is a BIOS w/a: Some BIOS wrap stolen in the root
 169                  * PCI bus, but have an off-by-one error. Hence retry the
 170                  * reservation starting from 1 instead of 0.
 171                  */
 172                 r = devm_request_mem_region(dev->dev, base + 1,
 173                                             dev_priv->gtt.stolen_size - 1,
 174                                             "Graphics Stolen Memory");
 175                 /*
 176                  * GEN3 firmware likes to smash pci bridges into the stolen
 177                  * range. Apparently this works.
 178                  */
 179                 if (r == NULL && !IS_GEN3(dev)) {
 180                         DRM_ERROR("conflict detected with stolen region: [0x%08x - 0x%08x]\n",
 181                                   base, base + (uint32_t)dev_priv->gtt.stolen_size);
 182                         base = 0;
 183                 }
 184         }
 185
 186         return base;
 187 }
 188
 189 void i915_gem_cleanup_stolen(struct drm_device *dev)
 190 {
 191         struct drm_i915_private *dev_priv = dev->dev_private;
 192
 193         if (!drm_mm_initialized(&dev_priv->mm.stolen))
 194                 return;
 195
 196         drm_mm_takedown(&dev_priv->mm.stolen);
 197 }
 198
 199 static void g4x_get_stolen_reserved(struct drm_i915_private *dev_priv,
 200                                     unsigned long *base, unsigned long *size)
 201 {
 202         uint32_t reg_val = I915_READ(IS_GM45(dev_priv) ?
 203                                      CTG_STOLEN_RESERVED :
 204                                      ELK_STOLEN_RESERVED);
 205         unsigned long stolen_top = dev_priv->mm.stolen_base +
 206                 dev_priv->gtt.stolen_size;
 207
 208         *base = (reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK) << 16;
 209
 210         WARN_ON((reg_val & G4X_STOLEN_RESERVED_ADDR1_MASK) < *base);
 211
 212         /* On these platforms, the register doesn't have a size field, so the
 213          * size is the distance between the base and the top of the stolen
 214          * memory. We also have the genuine case where base is zero and there's
 215          * nothing reserved. */
 216         if (*base == 0)
 217                 *size = 0;
 218         else
 219                 *size = stolen_top - *base;
 220 }
 221
 222 static void gen6_get_stolen_reserved(struct drm_i915_private *dev_priv,
 223                                      unsigned long *base, unsigned long *size)
 224 {
 225         uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
 226
 227         *base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;
 228
 229         switch (reg_val & GEN6_STOLEN_RESERVED_SIZE_MASK) {
 230         case GEN6_STOLEN_RESERVED_1M:
 231                 *size = 1024 * 1024;
 232                 break;
 233         case GEN6_STOLEN_RESERVED_512K:
 234                 *size = 512 * 1024;
 235                 break;
 236         case GEN6_STOLEN_RESERVED_256K:
 237                 *size = 256 * 1024;
 238                 break;
 239         case GEN6_STOLEN_RESERVED_128K:
 240                 *size = 128 * 1024;
 241                 break;
 242         default:
 243                 *size = 1024 * 1024;
 244                 MISSING_CASE(reg_val & GEN6_STOLEN_RESERVED_SIZE_MASK);
 245         }
 246 }
 247
 248 static void gen7_get_stolen_reserved(struct drm_i915_private *dev_priv,
 249                                      unsigned long *base, unsigned long *size)
 250 {
 251         uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
 252
 253         *base = reg_val & GEN7_STOLEN_RESERVED_ADDR_MASK;
 254
 255         switch (reg_val & GEN7_STOLEN_RESERVED_SIZE_MASK) {
 256         case GEN7_STOLEN_RESERVED_1M:
 257                 *size = 1024 * 1024;
 258                 break;
 259         case GEN7_STOLEN_RESERVED_256K:
 260                 *size = 256 * 1024;
 261                 break;
 262         default:
 263                 *size = 1024 * 1024;
 264                 MISSING_CASE(reg_val & GEN7_STOLEN_RESERVED_SIZE_MASK);
 265         }
 266 }
 267
 268 static void gen8_get_stolen_reserved(struct drm_i915_private *dev_priv,
 269                                      unsigned long *base, unsigned long *size)
 270 {
 271         uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
 272
 273         *base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;
 274
 275         switch (reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK) {
 276         case GEN8_STOLEN_RESERVED_1M:
 277                 *size = 1024 * 1024;
 278                 break;
 279         case GEN8_STOLEN_RESERVED_2M:
 280                 *size = 2 * 1024 * 1024;
 281                 break;
 282         case GEN8_STOLEN_RESERVED_4M:
 283                 *size = 4 * 1024 * 1024;
 284                 break;
 285         case GEN8_STOLEN_RESERVED_8M:
 286                 *size = 8 * 1024 * 1024;
 287                 break;
 288         default:
 289                 *size = 8 * 1024 * 1024;
 290                 MISSING_CASE(reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK);
 291         }
 292 }
 293
 294 static void bdw_get_stolen_reserved(struct drm_i915_private *dev_priv,
 295                                     unsigned long *base, unsigned long *size)
 296 {
 297         uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
 298         unsigned long stolen_top;
 299
 300         stolen_top = dev_priv->mm.stolen_base + dev_priv->gtt.stolen_size;
 301
 302         *base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;
 303
 304         /* On these platforms, the register doesn't have a size field, so the
 305          * size is the distance between the base and the top of the stolen
 306          * memory. We also have the genuine case where base is zero and there's
 307          * nothing reserved. */
 308         if (*base == 0)
 309                 *size = 0;
 310         else
 311                 *size = stolen_top - *base;
 312 }
 313
 314 int i915_gem_init_stolen(struct drm_device *dev)
 315 {
 316         struct drm_i915_private *dev_priv = dev->dev_private;
 317         unsigned long reserved_total, reserved_base = 0, reserved_size;
 318         unsigned long stolen_top;
 319
 320         mutex_init(&dev_priv->mm.stolen_lock);
 321
 322 #ifdef CONFIG_INTEL_IOMMU
 323         if (intel_iommu_gfx_mapped && INTEL_INFO(dev)->gen < 8) {
 324                 DRM_INFO("DMAR active, disabling use of stolen memory\n");
 325                 return 0;
 326         }
 327 #endif
 328
 329         if (dev_priv->gtt.stolen_size == 0)
 330                 return 0;
 331
 332         dev_priv->mm.stolen_base = i915_stolen_to_physical(dev);
 333         if (dev_priv->mm.stolen_base == 0)
 334                 return 0;
 335
 336         stolen_top = dev_priv->mm.stolen_base + dev_priv->gtt.stolen_size;
 337
 338         switch (INTEL_INFO(dev_priv)->gen) {
 339         case 2:
 340         case 3:
 341                 break;
 342         case 4:
 343                 if (IS_G4X(dev))
 344                         g4x_get_stolen_reserved(dev_priv, &reserved_base,
 345                                                 &reserved_size);
 346                 break;
 347         case 5:
 348                 /* Assume the gen6 maximum for the older platforms. */
 349                 reserved_size = 1024 * 1024;
 350                 reserved_base = stolen_top - reserved_size;
 351                 break;
 352         case 6:
 353                 gen6_get_stolen_reserved(dev_priv, &reserved_base,
 354                                          &reserved_size);
 355                 break;
 356         case 7:
 357                 gen7_get_stolen_reserved(dev_priv, &reserved_base,
 358                                          &reserved_size);
 359                 break;
 360         default:
 361                 if (IS_BROADWELL(dev_priv) || IS_SKYLAKE(dev_priv))
 362                         bdw_get_stolen_reserved(dev_priv, &reserved_base,
 363                                                 &reserved_size);
 364                 else
 365                         gen8_get_stolen_reserved(dev_priv, &reserved_base,
 366                                                  &reserved_size);
 367                 break;
 368         }
 369
 370         /* It is possible for the reserved base to be zero, but the register
 371          * field for size doesn't have a zero option. */
 372         if (reserved_base == 0) {
 373                 reserved_size = 0;
 374                 reserved_base = stolen_top;
 375         }
 376
 377         if (reserved_base < dev_priv->mm.stolen_base ||
 378             reserved_base + reserved_size > stolen_top) {
 379                 DRM_DEBUG_KMS("Stolen reserved area [0x%08lx - 0x%08lx] outside stolen memory [0x%08lx - 0x%08lx]\n",
 380                               reserved_base, reserved_base + reserved_size,
 381                               dev_priv->mm.stolen_base, stolen_top);
 382                 return 0;
 383         }
 384
 385         /* It is possible for the reserved area to end before the end of stolen
 386          * memory, so just consider the start. */
 387         reserved_total = stolen_top - reserved_base;
 388
 389         DRM_DEBUG_KMS("Memory reserved for graphics device: %zuK, usable: %luK\n",
 390                       dev_priv->gtt.stolen_size >> 10,
 391                       (dev_priv->gtt.stolen_size - reserved_total) >> 10);
 392
 393         dev_priv->gtt.stolen_usable_size = dev_priv->gtt.stolen_size -
 394                                            reserved_total;
 395
 396         /* Basic memrange allocator for stolen space */
 397         drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_usable_size);
 398
 399         return 0;
 400 }
 401
 402 static struct sg_table *
 403 i915_pages_create_for_stolen(struct drm_device *dev,
 404                              u32 offset, u32 size)
 405 {
 406         struct drm_i915_private *dev_priv = dev->dev_private;
 407         struct sg_table *st;
 408         struct scatterlist *sg;
 409
 410         DRM_DEBUG_DRIVER("offset=0x%x, size=%d\n", offset, size);
 411         BUG_ON(offset > dev_priv->gtt.stolen_size - size);
 412
 413         /* We hide that we have no struct page backing our stolen object
 414          * by wrapping the contiguous physical allocation with a fake
 415          * dma mapping in a single scatterlist.
 416          */
 417
 418         st = kmalloc(sizeof(*st), GFP_KERNEL);
 419         if (st == NULL)
 420                 return NULL;
 421
 422         if (sg_alloc_table(st, 1, GFP_KERNEL)) {
 423                 kfree(st);
 424                 return NULL;
 425         }
 426
 427         sg = st->sgl;
 428         sg->offset = 0;
 429         sg->length = size;
 430
 431         sg_dma_address(sg) = (dma_addr_t)dev_priv->mm.stolen_base + offset;
 432         sg_dma_len(sg) = size;
 433
 434         return st;
 435 }
 436
 437 static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
 438 {
 439         BUG();
 440         return -EINVAL;
 441 }
 442
 443 static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj)
 444 {
 445         /* Should only be called during free */
 446         sg_free_table(obj->pages);
 447         kfree(obj->pages);
 448 }
 449
 450
 451 static void
 452 i915_gem_object_release_stolen(struct drm_i915_gem_object *obj)
 453 {
 454         struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
 455
 456         if (obj->stolen) {
 457                 i915_gem_stolen_remove_node(dev_priv, obj->stolen);
 458                 kfree(obj->stolen);
 459                 obj->stolen = NULL;
 460         }
 461 }
 462 static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = {
 463         .get_pages = i915_gem_object_get_pages_stolen,
 464         .put_pages = i915_gem_object_put_pages_stolen,
 465         .release = i915_gem_object_release_stolen,
 466 };
 467
 468 static struct drm_i915_gem_object *
 469 _i915_gem_object_create_stolen(struct drm_device *dev,
 470                                struct drm_mm_node *stolen)
 471 {
 472         struct drm_i915_gem_object *obj;
 473
 474         obj = i915_gem_object_alloc(dev);
 475         if (obj == NULL)
 476                 return NULL;
 477
 478         drm_gem_private_object_init(dev, &obj->base, stolen->size);
 479         i915_gem_object_init(obj, &i915_gem_object_stolen_ops);
 480
 481         obj->pages = i915_pages_create_for_stolen(dev,
 482                                                   stolen->start, stolen->size);
 483         if (obj->pages == NULL)
 484                 goto cleanup;
 485
 486         i915_gem_object_pin_pages(obj);
 487         obj->stolen = stolen;
 488
 489         obj->base.read_domains = I915_GEM_DOMAIN_CPU | I915_GEM_DOMAIN_GTT;
 490         obj->cache_level = HAS_LLC(dev) ? I915_CACHE_LLC : I915_CACHE_NONE;
 491
 492         return obj;
 493
 494 cleanup:
 495         i915_gem_object_free(obj);
 496         return NULL;
 497 }
 498
 499 struct drm_i915_gem_object *
 500 i915_gem_object_create_stolen(struct drm_device *dev, u32 size)
 501 {
 502         struct drm_i915_private *dev_priv = dev->dev_private;
 503         struct drm_i915_gem_object *obj;
 504         struct drm_mm_node *stolen;
 505         int ret;
 506
 507         if (!drm_mm_initialized(&dev_priv->mm.stolen))
 508                 return NULL;
 509
 510         DRM_DEBUG_KMS("creating stolen object: size=%x\n", size);
 511         if (size == 0)
 512                 return NULL;
 513
 514         stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
 515         if (!stolen)
 516                 return NULL;
 517
 518         ret = i915_gem_stolen_insert_node(dev_priv, stolen, size, 4096);
 519         if (ret) {
 520                 kfree(stolen);
 521                 return NULL;
 522         }
 523
 524         obj = _i915_gem_object_create_stolen(dev, stolen);
 525         if (obj)
 526                 return obj;
 527
 528         i915_gem_stolen_remove_node(dev_priv, stolen);
 529         kfree(stolen);
 530         return NULL;
 531 }
 532
 533 struct drm_i915_gem_object *
 534 i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 535                                                u32 stolen_offset,
 536                                                u32 gtt_offset,
 537                                                u32 size)
 538 {
 539         struct drm_i915_private *dev_priv = dev->dev_private;
 540         struct i915_address_space *ggtt = &dev_priv->gtt.base;
 541         struct drm_i915_gem_object *obj;
 542         struct drm_mm_node *stolen;
 543         struct i915_vma *vma;
 544         int ret;
 545
 546         if (!drm_mm_initialized(&dev_priv->mm.stolen))
 547                 return NULL;
 548
 549         DRM_DEBUG_KMS("creating preallocated stolen object: stolen_offset=%x, gtt_offset=%x, size=%x\n",
 550                         stolen_offset, gtt_offset, size);
 551
 552         /* KISS and expect everything to be page-aligned */
 553         if (WARN_ON(size == 0) || WARN_ON(size & 4095) ||
 554             WARN_ON(stolen_offset & 4095))
 555                 return NULL;
 556
 557         stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
 558         if (!stolen)
 559                 return NULL;
 560
 561         stolen->start = stolen_offset;
 562         stolen->size = size;
 563         mutex_lock(&dev_priv->mm.stolen_lock);
 564         ret = drm_mm_reserve_node(&dev_priv->mm.stolen, stolen);
 565         mutex_unlock(&dev_priv->mm.stolen_lock);
 566         if (ret) {
 567                 DRM_DEBUG_KMS("failed to allocate stolen space\n");
 568                 kfree(stolen);
 569                 return NULL;
 570         }
 571
 572         obj = _i915_gem_object_create_stolen(dev, stolen);
 573         if (obj == NULL) {
 574                 DRM_DEBUG_KMS("failed to allocate stolen object\n");
 575                 i915_gem_stolen_remove_node(dev_priv, stolen);
 576                 kfree(stolen);
 577                 return NULL;
 578         }
 579
 580         /* Some objects just need physical mem from stolen space */
 581         if (gtt_offset == I915_GTT_OFFSET_NONE)
 582                 return obj;
 583
 584         vma = i915_gem_obj_lookup_or_create_vma(obj, ggtt);
 585         if (IS_ERR(vma)) {
 586                 ret = PTR_ERR(vma);
 587                 goto err;
 588         }
 589
 590         /* To simplify the initialisation sequence between KMS and GTT,
 591          * we allow construction of the stolen object prior to
 592          * setting up the GTT space. The actual reservation will occur
 593          * later.
 594          */
 595         vma->node.start = gtt_offset;
 596         vma->node.size = size;
 597         if (drm_mm_initialized(&ggtt->mm)) {
 598                 ret = drm_mm_reserve_node(&ggtt->mm, &vma->node);
 599                 if (ret) {
 600                         DRM_DEBUG_KMS("failed to allocate stolen GTT space\n");
 601                         goto err;
 602                 }
 603
 604                 vma->bound |= GLOBAL_BIND;
 605                 list_add_tail(&vma->mm_list, &ggtt->inactive_list);
 606         }
 607
 608         list_add_tail(&obj->global_list, &dev_priv->mm.bound_list);
 609         i915_gem_object_pin_pages(obj);
 610
 611         return obj;
 612
 613 err:
 614         drm_gem_object_unreference(&obj->base);
 615         return NULL;
 616 }