drivers/gpu/drm/i915/i915_gem_gtt.c

   1 /*
   2  * Copyright © 2010 Daniel Vetter
   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  */
  24
  25 #include <drm/drmP.h>
  26 #include <drm/i915_drm.h>
  27 #include "i915_drv.h"
  28 #include "i915_trace.h"
  29 #include "intel_drv.h"
  30
  31 typedef uint32_t gtt_pte_t;
  32
  33 /* PPGTT stuff */
  34 #define GEN6_GTT_ADDR_ENCODE(addr)      ((addr) | (((addr) >> 28) & 0xff0))
  35
  36 #define GEN6_PDE_VALID                  (1 << 0)
  37 /* gen6+ has bit 11-4 for physical addr bit 39-32 */
  38 #define GEN6_PDE_ADDR_ENCODE(addr)      GEN6_GTT_ADDR_ENCODE(addr)
  39
  40 #define GEN6_PTE_VALID                  (1 << 0)
  41 #define GEN6_PTE_UNCACHED               (1 << 1)
  42 #define HSW_PTE_UNCACHED                (0)
  43 #define GEN6_PTE_CACHE_LLC              (2 << 1)
  44 #define GEN6_PTE_CACHE_LLC_MLC          (3 << 1)
  45 #define GEN6_PTE_ADDR_ENCODE(addr)      GEN6_GTT_ADDR_ENCODE(addr)
  46
  47 static inline gtt_pte_t pte_encode(struct drm_device *dev,
  48                                    dma_addr_t addr,
  49                                    enum i915_cache_level level)
  50 {
  51         gtt_pte_t pte = GEN6_PTE_VALID;
  52         pte |= GEN6_PTE_ADDR_ENCODE(addr);
  53
  54         switch (level) {
  55         case I915_CACHE_LLC_MLC:
  56                 /* Haswell doesn't set L3 this way */
  57                 if (IS_HASWELL(dev))
  58                         pte |= GEN6_PTE_CACHE_LLC;
  59                 else
  60                         pte |= GEN6_PTE_CACHE_LLC_MLC;
  61                 break;
  62         case I915_CACHE_LLC:
  63                 pte |= GEN6_PTE_CACHE_LLC;
  64                 break;
  65         case I915_CACHE_NONE:
  66                 if (IS_HASWELL(dev))
  67                         pte |= HSW_PTE_UNCACHED;
  68                 else
  69                         pte |= GEN6_PTE_UNCACHED;
  70                 break;
  71         default:
  72                 BUG();
  73         }
  74
  75
  76         return pte;
  77 }
  78
  79 /* PPGTT support for Sandybdrige/Gen6 and later */
  80 static void i915_ppgtt_clear_range(struct i915_hw_ppgtt *ppgtt,
  81                                    unsigned first_entry,
  82                                    unsigned num_entries)
  83 {
  84         gtt_pte_t *pt_vaddr;
  85         gtt_pte_t scratch_pte;
  86         unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
  87         unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
  88         unsigned last_pte, i;
  89
  90         scratch_pte = pte_encode(ppgtt->dev, ppgtt->scratch_page_dma_addr,
  91                                  I915_CACHE_LLC);
  92
  93         while (num_entries) {
  94                 last_pte = first_pte + num_entries;
  95                 if (last_pte > I915_PPGTT_PT_ENTRIES)
  96                         last_pte = I915_PPGTT_PT_ENTRIES;
  97
  98                 pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);
  99
 100                 for (i = first_pte; i < last_pte; i++)
 101                         pt_vaddr[i] = scratch_pte;
 102
 103                 kunmap_atomic(pt_vaddr);
 104
 105                 num_entries -= last_pte - first_pte;
 106                 first_pte = 0;
 107                 act_pd++;
 108         }
 109 }
 110
 111 int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)
 112 {
 113         struct drm_i915_private *dev_priv = dev->dev_private;
 114         struct i915_hw_ppgtt *ppgtt;
 115         unsigned first_pd_entry_in_global_pt;
 116         int i;
 117         int ret = -ENOMEM;
 118
 119         /* ppgtt PDEs reside in the global gtt pagetable, which has 512*1024
 120          * entries. For aliasing ppgtt support we just steal them at the end for
 121          * now. */
 122         first_pd_entry_in_global_pt = dev_priv->mm.gtt->gtt_total_entries - I915_PPGTT_PD_ENTRIES;
 123
 124         ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
 125         if (!ppgtt)
 126                 return ret;
 127
 128         ppgtt->dev = dev;
 129         ppgtt->num_pd_entries = I915_PPGTT_PD_ENTRIES;
 130         ppgtt->pt_pages = kzalloc(sizeof(struct page *)*ppgtt->num_pd_entries,
 131                                   GFP_KERNEL);
 132         if (!ppgtt->pt_pages)
 133                 goto err_ppgtt;
 134
 135         for (i = 0; i < ppgtt->num_pd_entries; i++) {
 136                 ppgtt->pt_pages[i] = alloc_page(GFP_KERNEL);
 137                 if (!ppgtt->pt_pages[i])
 138                         goto err_pt_alloc;
 139         }
 140
 141         if (dev_priv->mm.gtt->needs_dmar) {
 142                 ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t)
 143                                                 *ppgtt->num_pd_entries,
 144                                              GFP_KERNEL);
 145                 if (!ppgtt->pt_dma_addr)
 146                         goto err_pt_alloc;
 147
 148                 for (i = 0; i < ppgtt->num_pd_entries; i++) {
 149                         dma_addr_t pt_addr;
 150
 151                         pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i],
 152                                                0, 4096,
 153                                                PCI_DMA_BIDIRECTIONAL);
 154
 155                         if (pci_dma_mapping_error(dev->pdev,
 156                                                   pt_addr)) {
 157                                 ret = -EIO;
 158                                 goto err_pd_pin;
 159
 160                         }
 161                         ppgtt->pt_dma_addr[i] = pt_addr;
 162                 }
 163         }
 164
 165         ppgtt->scratch_page_dma_addr = dev_priv->mm.gtt->scratch_page_dma;
 166
 167         i915_ppgtt_clear_range(ppgtt, 0,
 168                                ppgtt->num_pd_entries*I915_PPGTT_PT_ENTRIES);
 169
 170         ppgtt->pd_offset = (first_pd_entry_in_global_pt)*sizeof(gtt_pte_t);
 171
 172         dev_priv->mm.aliasing_ppgtt = ppgtt;
 173
 174         return 0;
 175
 176 err_pd_pin:
 177         if (ppgtt->pt_dma_addr) {
 178                 for (i--; i >= 0; i--)
 179                         pci_unmap_page(dev->pdev, ppgtt->pt_dma_addr[i],
 180                                        4096, PCI_DMA_BIDIRECTIONAL);
 181         }
 182 err_pt_alloc:
 183         kfree(ppgtt->pt_dma_addr);
 184         for (i = 0; i < ppgtt->num_pd_entries; i++) {
 185                 if (ppgtt->pt_pages[i])
 186                         __free_page(ppgtt->pt_pages[i]);
 187         }
 188         kfree(ppgtt->pt_pages);
 189 err_ppgtt:
 190         kfree(ppgtt);
 191
 192         return ret;
 193 }
 194
 195 void i915_gem_cleanup_aliasing_ppgtt(struct drm_device *dev)
 196 {
 197         struct drm_i915_private *dev_priv = dev->dev_private;
 198         struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;
 199         int i;
 200
 201         if (!ppgtt)
 202                 return;
 203
 204         if (ppgtt->pt_dma_addr) {
 205                 for (i = 0; i < ppgtt->num_pd_entries; i++)
 206                         pci_unmap_page(dev->pdev, ppgtt->pt_dma_addr[i],
 207                                        4096, PCI_DMA_BIDIRECTIONAL);
 208         }
 209
 210         kfree(ppgtt->pt_dma_addr);
 211         for (i = 0; i < ppgtt->num_pd_entries; i++)
 212                 __free_page(ppgtt->pt_pages[i]);
 213         kfree(ppgtt->pt_pages);
 214         kfree(ppgtt);
 215 }
 216
 217 static void i915_ppgtt_insert_sg_entries(struct i915_hw_ppgtt *ppgtt,
 218                                          const struct sg_table *pages,
 219                                          unsigned first_entry,
 220                                          enum i915_cache_level cache_level)
 221 {
 222         gtt_pte_t *pt_vaddr;
 223         unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
 224         unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
 225         unsigned i, j, m, segment_len;
 226         dma_addr_t page_addr;
 227         struct scatterlist *sg;
 228
 229         /* init sg walking */
 230         sg = pages->sgl;
 231         i = 0;
 232         segment_len = sg_dma_len(sg) >> PAGE_SHIFT;
 233         m = 0;
 234
 235         while (i < pages->nents) {
 236                 pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);
 237
 238                 for (j = first_pte; j < I915_PPGTT_PT_ENTRIES; j++) {
 239                         page_addr = sg_dma_address(sg) + (m << PAGE_SHIFT);
 240                         pt_vaddr[j] = pte_encode(ppgtt->dev, page_addr,
 241                                                  cache_level);
 242
 243                         /* grab the next page */
 244                         if (++m == segment_len) {
 245                                 if (++i == pages->nents)
 246                                         break;
 247
 248                                 sg = sg_next(sg);
 249                                 segment_len = sg_dma_len(sg) >> PAGE_SHIFT;
 250                                 m = 0;
 251                         }
 252                 }
 253
 254                 kunmap_atomic(pt_vaddr);
 255
 256                 first_pte = 0;
 257                 act_pd++;
 258         }
 259 }
 260
 261 void i915_ppgtt_bind_object(struct i915_hw_ppgtt *ppgtt,
 262                             struct drm_i915_gem_object *obj,
 263                             enum i915_cache_level cache_level)
 264 {
 265         i915_ppgtt_insert_sg_entries(ppgtt,
 266                                      obj->pages,
 267                                      obj->gtt_space->start >> PAGE_SHIFT,
 268                                      cache_level);
 269 }
 270
 271 void i915_ppgtt_unbind_object(struct i915_hw_ppgtt *ppgtt,
 272                               struct drm_i915_gem_object *obj)
 273 {
 274         i915_ppgtt_clear_range(ppgtt,
 275                                obj->gtt_space->start >> PAGE_SHIFT,
 276                                obj->base.size >> PAGE_SHIFT);
 277 }
 278
 279 void i915_gem_init_ppgtt(struct drm_device *dev)
 280 {
 281         drm_i915_private_t *dev_priv = dev->dev_private;
 282         uint32_t pd_offset;
 283         struct intel_ring_buffer *ring;
 284         struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;
 285         gtt_pte_t __iomem *pd_addr;
 286         uint32_t pd_entry;
 287         int i;
 288
 289         if (!dev_priv->mm.aliasing_ppgtt)
 290                 return;
 291
 292
 293         pd_addr = dev_priv->mm.gtt->gtt + ppgtt->pd_offset/sizeof(gtt_pte_t);
 294         for (i = 0; i < ppgtt->num_pd_entries; i++) {
 295                 dma_addr_t pt_addr;
 296
 297                 if (dev_priv->mm.gtt->needs_dmar)
 298                         pt_addr = ppgtt->pt_dma_addr[i];
 299                 else
 300                         pt_addr = page_to_phys(ppgtt->pt_pages[i]);
 301
 302                 pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);
 303                 pd_entry |= GEN6_PDE_VALID;
 304
 305                 writel(pd_entry, pd_addr + i);
 306         }
 307         readl(pd_addr);
 308
 309         pd_offset = ppgtt->pd_offset;
 310         pd_offset /= 64; /* in cachelines, */
 311         pd_offset <<= 16;
 312
 313         if (INTEL_INFO(dev)->gen == 6) {
 314                 uint32_t ecochk, gab_ctl, ecobits;
 315
 316                 ecobits = I915_READ(GAC_ECO_BITS);
 317                 I915_WRITE(GAC_ECO_BITS, ecobits | ECOBITS_PPGTT_CACHE64B);
 318
 319                 gab_ctl = I915_READ(GAB_CTL);
 320                 I915_WRITE(GAB_CTL, gab_ctl | GAB_CTL_CONT_AFTER_PAGEFAULT);
 321
 322                 ecochk = I915_READ(GAM_ECOCHK);
 323                 I915_WRITE(GAM_ECOCHK, ecochk | ECOCHK_SNB_BIT |
 324                                        ECOCHK_PPGTT_CACHE64B);
 325                 I915_WRITE(GFX_MODE, _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
 326         } else if (INTEL_INFO(dev)->gen >= 7) {
 327                 I915_WRITE(GAM_ECOCHK, ECOCHK_PPGTT_CACHE64B);
 328                 /* GFX_MODE is per-ring on gen7+ */
 329         }
 330
 331         for_each_ring(ring, dev_priv, i) {
 332                 if (INTEL_INFO(dev)->gen >= 7)
 333                         I915_WRITE(RING_MODE_GEN7(ring),
 334                                    _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
 335
 336                 I915_WRITE(RING_PP_DIR_DCLV(ring), PP_DIR_DCLV_2G);
 337                 I915_WRITE(RING_PP_DIR_BASE(ring), pd_offset);
 338         }
 339 }
 340
 341 static bool do_idling(struct drm_i915_private *dev_priv)
 342 {
 343         bool ret = dev_priv->mm.interruptible;
 344
 345         if (unlikely(dev_priv->mm.gtt->do_idle_maps)) {
 346                 dev_priv->mm.interruptible = false;
 347                 if (i915_gpu_idle(dev_priv->dev)) {
 348                         DRM_ERROR("Couldn't idle GPU\n");
 349                         /* Wait a bit, in hopes it avoids the hang */
 350                         udelay(10);
 351                 }
 352         }
 353
 354         return ret;
 355 }
 356
 357 static void undo_idling(struct drm_i915_private *dev_priv, bool interruptible)
 358 {
 359         if (unlikely(dev_priv->mm.gtt->do_idle_maps))
 360                 dev_priv->mm.interruptible = interruptible;
 361 }
 362
 363
 364 static void i915_ggtt_clear_range(struct drm_device *dev,
 365                                  unsigned first_entry,
 366                                  unsigned num_entries)
 367 {
 368         struct drm_i915_private *dev_priv = dev->dev_private;
 369         gtt_pte_t scratch_pte;
 370         gtt_pte_t __iomem *gtt_base = dev_priv->mm.gtt->gtt + first_entry;
 371         const int max_entries = dev_priv->mm.gtt->gtt_total_entries - first_entry;
 372         int i;
 373
 374         if (INTEL_INFO(dev)->gen < 6) {
 375                 intel_gtt_clear_range(first_entry, num_entries);
 376                 return;
 377         }
 378
 379         if (WARN(num_entries > max_entries,
 380                  "First entry = %d; Num entries = %d (max=%d)\n",
 381                  first_entry, num_entries, max_entries))
 382                 num_entries = max_entries;
 383
 384         scratch_pte = pte_encode(dev, dev_priv->mm.gtt->scratch_page_dma, I915_CACHE_LLC);
 385         for (i = 0; i < num_entries; i++)
 386                 iowrite32(scratch_pte, &gtt_base[i]);
 387         readl(gtt_base);
 388 }
 389
 390 void i915_gem_restore_gtt_mappings(struct drm_device *dev)
 391 {
 392         struct drm_i915_private *dev_priv = dev->dev_private;
 393         struct drm_i915_gem_object *obj;
 394
 395         /* First fill our portion of the GTT with scratch pages */
 396         i915_ggtt_clear_range(dev, dev_priv->mm.gtt_start / PAGE_SIZE,
 397                               (dev_priv->mm.gtt_end - dev_priv->mm.gtt_start) / PAGE_SIZE);
 398
 399         list_for_each_entry(obj, &dev_priv->mm.bound_list, gtt_list) {
 400                 i915_gem_clflush_object(obj);
 401                 i915_gem_gtt_bind_object(obj, obj->cache_level);
 402         }
 403
 404         i915_gem_chipset_flush(dev);
 405 }
 406
 407 int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
 408 {
 409         if (obj->has_dma_mapping)
 410                 return 0;
 411
 412         if (!dma_map_sg(&obj->base.dev->pdev->dev,
 413                         obj->pages->sgl, obj->pages->nents,
 414                         PCI_DMA_BIDIRECTIONAL))
 415                 return -ENOSPC;
 416
 417         return 0;
 418 }
 419
 420 /*
 421  * Binds an object into the global gtt with the specified cache level. The object
 422  * will be accessible to the GPU via commands whose operands reference offsets
 423  * within the global GTT as well as accessible by the GPU through the GMADR
 424  * mapped BAR (dev_priv->mm.gtt->gtt).
 425  */
 426 static void gen6_ggtt_bind_object(struct drm_i915_gem_object *obj,
 427                                   enum i915_cache_level level)
 428 {
 429         struct drm_device *dev = obj->base.dev;
 430         struct drm_i915_private *dev_priv = dev->dev_private;
 431         struct sg_table *st = obj->pages;
 432         struct scatterlist *sg = st->sgl;
 433         const int first_entry = obj->gtt_space->start >> PAGE_SHIFT;
 434         const int max_entries = dev_priv->mm.gtt->gtt_total_entries - first_entry;
 435         gtt_pte_t __iomem *gtt_entries = dev_priv->mm.gtt->gtt + first_entry;
 436         int unused, i = 0;
 437         unsigned int len, m = 0;
 438         dma_addr_t addr;
 439
 440         for_each_sg(st->sgl, sg, st->nents, unused) {
 441                 len = sg_dma_len(sg) >> PAGE_SHIFT;
 442                 for (m = 0; m < len; m++) {
 443                         addr = sg_dma_address(sg) + (m << PAGE_SHIFT);
 444                         iowrite32(pte_encode(dev, addr, level), &gtt_entries[i]);
 445                         i++;
 446                 }
 447         }
 448
 449         BUG_ON(i > max_entries);
 450         BUG_ON(i != obj->base.size / PAGE_SIZE);
 451
 452         /* XXX: This serves as a posting read to make sure that the PTE has
 453          * actually been updated. There is some concern that even though
 454          * registers and PTEs are within the same BAR that they are potentially
 455          * of NUMA access patterns. Therefore, even with the way we assume
 456          * hardware should work, we must keep this posting read for paranoia.
 457          */
 458         if (i != 0)
 459                 WARN_ON(readl(&gtt_entries[i-1]) != pte_encode(dev, addr, level));
 460
 461         /* This next bit makes the above posting read even more important. We
 462          * want to flush the TLBs only after we're certain all the PTE updates
 463          * have finished.
 464          */
 465         I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
 466         POSTING_READ(GFX_FLSH_CNTL_GEN6);
 467 }
 468
 469 void i915_gem_gtt_bind_object(struct drm_i915_gem_object *obj,
 470                               enum i915_cache_level cache_level)
 471 {
 472         struct drm_device *dev = obj->base.dev;
 473         if (INTEL_INFO(dev)->gen < 6) {
 474                 unsigned int flags = (cache_level == I915_CACHE_NONE) ?
 475                         AGP_USER_MEMORY : AGP_USER_CACHED_MEMORY;
 476                 intel_gtt_insert_sg_entries(obj->pages,
 477                                             obj->gtt_space->start >> PAGE_SHIFT,
 478                                             flags);
 479         } else {
 480                 gen6_ggtt_bind_object(obj, cache_level);
 481         }
 482
 483         obj->has_global_gtt_mapping = 1;
 484 }
 485
 486 void i915_gem_gtt_unbind_object(struct drm_i915_gem_object *obj)
 487 {
 488         i915_ggtt_clear_range(obj->base.dev,
 489                               obj->gtt_space->start >> PAGE_SHIFT,
 490                               obj->base.size >> PAGE_SHIFT);
 491
 492         obj->has_global_gtt_mapping = 0;
 493 }
 494
 495 void i915_gem_gtt_finish_object(struct drm_i915_gem_object *obj)
 496 {
 497         struct drm_device *dev = obj->base.dev;
 498         struct drm_i915_private *dev_priv = dev->dev_private;
 499         bool interruptible;
 500
 501         interruptible = do_idling(dev_priv);
 502
 503         if (!obj->has_dma_mapping)
 504                 dma_unmap_sg(&dev->pdev->dev,
 505                              obj->pages->sgl, obj->pages->nents,
 506                              PCI_DMA_BIDIRECTIONAL);
 507
 508         undo_idling(dev_priv, interruptible);
 509 }
 510
 511 static void i915_gtt_color_adjust(struct drm_mm_node *node,
 512                                   unsigned long color,
 513                                   unsigned long *start,
 514                                   unsigned long *end)
 515 {
 516         if (node->color != color)
 517                 *start += 4096;
 518
 519         if (!list_empty(&node->node_list)) {
 520                 node = list_entry(node->node_list.next,
 521                                   struct drm_mm_node,
 522                                   node_list);
 523                 if (node->allocated && node->color != color)
 524                         *end -= 4096;
 525         }
 526 }
 527
 528 void i915_gem_init_global_gtt(struct drm_device *dev,
 529                               unsigned long start,
 530                               unsigned long mappable_end,
 531                               unsigned long end)
 532 {
 533         drm_i915_private_t *dev_priv = dev->dev_private;
 534         struct drm_mm_node *entry;
 535         struct drm_i915_gem_object *obj;
 536         unsigned long hole_start, hole_end;
 537
 538         /* Subtract the guard page ... */
 539         drm_mm_init(&dev_priv->mm.gtt_space, start, end - start - PAGE_SIZE);
 540         if (!HAS_LLC(dev))
 541                 dev_priv->mm.gtt_space.color_adjust = i915_gtt_color_adjust;
 542
 543         /* Mark any preallocated objects as occupied */
 544         list_for_each_entry(obj, &dev_priv->mm.bound_list, gtt_list) {
 545                 DRM_DEBUG_KMS("reserving preallocated space: %x + %zx\n",
 546                               obj->gtt_offset, obj->base.size);
 547
 548                 BUG_ON(obj->gtt_space != I915_GTT_RESERVED);
 549                 obj->gtt_space = drm_mm_create_block(&dev_priv->mm.gtt_space,
 550                                                      obj->gtt_offset,
 551                                                      obj->base.size,
 552                                                      false);
 553                 obj->has_global_gtt_mapping = 1;
 554         }
 555
 556         dev_priv->mm.gtt_start = start;
 557         dev_priv->mm.gtt_mappable_end = mappable_end;
 558         dev_priv->mm.gtt_end = end;
 559         dev_priv->mm.gtt_total = end - start;
 560         dev_priv->mm.mappable_gtt_total = min(end, mappable_end) - start;
 561
 562         /* Clear any non-preallocated blocks */
 563         drm_mm_for_each_hole(entry, &dev_priv->mm.gtt_space,
 564                              hole_start, hole_end) {
 565                 DRM_DEBUG_KMS("clearing unused GTT space: [%lx, %lx]\n",
 566                               hole_start, hole_end);
 567                 i915_ggtt_clear_range(dev,
 568                                       hole_start / PAGE_SIZE,
 569                                       (hole_end-hole_start) / PAGE_SIZE);
 570         }
 571
 572         /* And finally clear the reserved guard page */
 573         i915_ggtt_clear_range(dev, end / PAGE_SIZE - 1, 1);
 574 }
 575
 576 static int setup_scratch_page(struct drm_device *dev)
 577 {
 578         struct drm_i915_private *dev_priv = dev->dev_private;
 579         struct page *page;
 580         dma_addr_t dma_addr;
 581
 582         page = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
 583         if (page == NULL)
 584                 return -ENOMEM;
 585         get_page(page);
 586         set_pages_uc(page, 1);
 587
 588 #ifdef CONFIG_INTEL_IOMMU
 589         dma_addr = pci_map_page(dev->pdev, page, 0, PAGE_SIZE,
 590                                 PCI_DMA_BIDIRECTIONAL);
 591         if (pci_dma_mapping_error(dev->pdev, dma_addr))
 592                 return -EINVAL;
 593 #else
 594         dma_addr = page_to_phys(page);
 595 #endif
 596         dev_priv->mm.gtt->scratch_page = page;
 597         dev_priv->mm.gtt->scratch_page_dma = dma_addr;
 598
 599         return 0;
 600 }
 601
 602 static void teardown_scratch_page(struct drm_device *dev)
 603 {
 604         struct drm_i915_private *dev_priv = dev->dev_private;
 605         set_pages_wb(dev_priv->mm.gtt->scratch_page, 1);
 606         pci_unmap_page(dev->pdev, dev_priv->mm.gtt->scratch_page_dma,
 607                        PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
 608         put_page(dev_priv->mm.gtt->scratch_page);
 609         __free_page(dev_priv->mm.gtt->scratch_page);
 610 }
 611
 612 static inline unsigned int gen6_get_total_gtt_size(u16 snb_gmch_ctl)
 613 {
 614         snb_gmch_ctl >>= SNB_GMCH_GGMS_SHIFT;
 615         snb_gmch_ctl &= SNB_GMCH_GGMS_MASK;
 616         return snb_gmch_ctl << 20;
 617 }
 618
 619 static inline unsigned int gen6_get_stolen_size(u16 snb_gmch_ctl)
 620 {
 621         snb_gmch_ctl >>= SNB_GMCH_GMS_SHIFT;
 622         snb_gmch_ctl &= SNB_GMCH_GMS_MASK;
 623         return snb_gmch_ctl << 25; /* 32 MB units */
 624 }
 625
 626 static inline unsigned int gen7_get_stolen_size(u16 snb_gmch_ctl)
 627 {
 628         static const int stolen_decoder[] = {
 629                 0, 0, 0, 0, 0, 32, 48, 64, 128, 256, 96, 160, 224, 352};
 630         snb_gmch_ctl >>= IVB_GMCH_GMS_SHIFT;
 631         snb_gmch_ctl &= IVB_GMCH_GMS_MASK;
 632         return stolen_decoder[snb_gmch_ctl] << 20;
 633 }
 634
 635 int i915_gem_gtt_init(struct drm_device *dev)
 636 {
 637         struct drm_i915_private *dev_priv = dev->dev_private;
 638         phys_addr_t gtt_bus_addr;
 639         u16 snb_gmch_ctl;
 640         int ret;
 641
 642         /* On modern platforms we need not worry ourself with the legacy
 643          * hostbridge query stuff. Skip it entirely
 644          */
 645         if (INTEL_INFO(dev)->gen < 6) {
 646                 ret = intel_gmch_probe(dev_priv->bridge_dev, dev->pdev, NULL);
 647                 if (!ret) {
 648                         DRM_ERROR("failed to set up gmch\n");
 649                         return -EIO;
 650                 }
 651
 652                 dev_priv->mm.gtt = intel_gtt_get();
 653                 if (!dev_priv->mm.gtt) {
 654                         DRM_ERROR("Failed to initialize GTT\n");
 655                         intel_gmch_remove();
 656                         return -ENODEV;
 657                 }
 658                 return 0;
 659         }
 660
 661         dev_priv->mm.gtt = kzalloc(sizeof(*dev_priv->mm.gtt), GFP_KERNEL);
 662         if (!dev_priv->mm.gtt)
 663                 return -ENOMEM;
 664
 665         if (!pci_set_dma_mask(dev->pdev, DMA_BIT_MASK(40)))
 666                 pci_set_consistent_dma_mask(dev->pdev, DMA_BIT_MASK(40));
 667
 668         /* For GEN6+ the PTEs for the ggtt live at 2MB + BAR0 */
 669         gtt_bus_addr = pci_resource_start(dev->pdev, 0) + (2<<20);
 670         dev_priv->mm.gtt->gma_bus_addr = pci_resource_start(dev->pdev, 2);
 671
 672         /* i9xx_setup */
 673         pci_read_config_word(dev->pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
 674         dev_priv->mm.gtt->gtt_total_entries =
 675                 gen6_get_total_gtt_size(snb_gmch_ctl) / sizeof(gtt_pte_t);
 676         if (INTEL_INFO(dev)->gen < 7)
 677                 dev_priv->mm.gtt->stolen_size = gen6_get_stolen_size(snb_gmch_ctl);
 678         else
 679                 dev_priv->mm.gtt->stolen_size = gen7_get_stolen_size(snb_gmch_ctl);
 680
 681         dev_priv->mm.gtt->gtt_mappable_entries = pci_resource_len(dev->pdev, 2) >> PAGE_SHIFT;
 682         /* 64/512MB is the current min/max we actually know of, but this is just a
 683          * coarse sanity check.
 684          */
 685         if ((dev_priv->mm.gtt->gtt_mappable_entries >> 8) < 64 ||
 686             dev_priv->mm.gtt->gtt_mappable_entries > dev_priv->mm.gtt->gtt_total_entries) {
 687                 DRM_ERROR("Unknown GMADR entries (%d)\n",
 688                           dev_priv->mm.gtt->gtt_mappable_entries);
 689                 ret = -ENXIO;
 690                 goto err_out;
 691         }
 692
 693         ret = setup_scratch_page(dev);
 694         if (ret) {
 695                 DRM_ERROR("Scratch setup failed\n");
 696                 goto err_out;
 697         }
 698
 699         dev_priv->mm.gtt->gtt = ioremap_wc(gtt_bus_addr,
 700                                            dev_priv->mm.gtt->gtt_total_entries * sizeof(gtt_pte_t));
 701         if (!dev_priv->mm.gtt->gtt) {
 702                 DRM_ERROR("Failed to map the gtt page table\n");
 703                 teardown_scratch_page(dev);
 704                 ret = -ENOMEM;
 705                 goto err_out;
 706         }
 707
 708         /* GMADR is the PCI aperture used by SW to access tiled GFX surfaces in a linear fashion. */
 709         DRM_INFO("Memory usable by graphics device = %dM\n", dev_priv->mm.gtt->gtt_total_entries >> 8);
 710         DRM_DEBUG_DRIVER("GMADR size = %dM\n", dev_priv->mm.gtt->gtt_mappable_entries >> 8);
 711         DRM_DEBUG_DRIVER("GTT stolen size = %dM\n", dev_priv->mm.gtt->stolen_size >> 20);
 712
 713         return 0;
 714
 715 err_out:
 716         kfree(dev_priv->mm.gtt);
 717         if (INTEL_INFO(dev)->gen < 6)
 718                 intel_gmch_remove();
 719         return ret;
 720 }
 721
 722 void i915_gem_gtt_fini(struct drm_device *dev)
 723 {
 724         struct drm_i915_private *dev_priv = dev->dev_private;
 725         iounmap(dev_priv->mm.gtt->gtt);
 726         teardown_scratch_page(dev);
 727         if (INTEL_INFO(dev)->gen < 6)
 728                 intel_gmch_remove();
 729         kfree(dev_priv->mm.gtt);
 730 }