drivers/gpu/drm/drm_gem_vram_helper.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 #include <drm/drm_gem_vram_helper.h>
   4 #include <drm/drm_device.h>
   5 #include <drm/drm_mode.h>
   6 #include <drm/drm_prime.h>
   7 #include <drm/drm_vram_mm_helper.h>
   8 #include <drm/ttm/ttm_page_alloc.h>
   9
  10 static const struct drm_gem_object_funcs drm_gem_vram_object_funcs;
  11
  12 /**
  13  * DOC: overview
  14  *
  15  * This library provides a GEM buffer object that is backed by video RAM
  16  * (VRAM). It can be used for framebuffer devices with dedicated memory.
  17  */
  18
  19 /*
  20  * Buffer-objects helpers
  21  */
  22
  23 static void drm_gem_vram_cleanup(struct drm_gem_vram_object *gbo)
  24 {
  25         /* We got here via ttm_bo_put(), which means that the
  26          * TTM buffer object in 'bo' has already been cleaned
  27          * up; only release the GEM object.
  28          */
  29         drm_gem_object_release(&gbo->bo.base);
  30 }
  31
  32 static void drm_gem_vram_destroy(struct drm_gem_vram_object *gbo)
  33 {
  34         drm_gem_vram_cleanup(gbo);
  35         kfree(gbo);
  36 }
  37
  38 static void ttm_buffer_object_destroy(struct ttm_buffer_object *bo)
  39 {
  40         struct drm_gem_vram_object *gbo = drm_gem_vram_of_bo(bo);
  41
  42         drm_gem_vram_destroy(gbo);
  43 }
  44
  45 static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo,
  46                                    unsigned long pl_flag)
  47 {
  48         unsigned int i;
  49         unsigned int c = 0;
  50
  51         gbo->placement.placement = gbo->placements;
  52         gbo->placement.busy_placement = gbo->placements;
  53
  54         if (pl_flag & TTM_PL_FLAG_VRAM)
  55                 gbo->placements[c++].flags = TTM_PL_FLAG_WC |
  56                                              TTM_PL_FLAG_UNCACHED |
  57                                              TTM_PL_FLAG_VRAM;
  58
  59         if (pl_flag & TTM_PL_FLAG_SYSTEM)
  60                 gbo->placements[c++].flags = TTM_PL_MASK_CACHING |
  61                                              TTM_PL_FLAG_SYSTEM;
  62
  63         if (!c)
  64                 gbo->placements[c++].flags = TTM_PL_MASK_CACHING |
  65                                              TTM_PL_FLAG_SYSTEM;
  66
  67         gbo->placement.num_placement = c;
  68         gbo->placement.num_busy_placement = c;
  69
  70         for (i = 0; i < c; ++i) {
  71                 gbo->placements[i].fpfn = 0;
  72                 gbo->placements[i].lpfn = 0;
  73         }
  74 }
  75
  76 static int drm_gem_vram_init(struct drm_device *dev,
  77                              struct ttm_bo_device *bdev,
  78                              struct drm_gem_vram_object *gbo,
  79                              size_t size, unsigned long pg_align,
  80                              bool interruptible)
  81 {
  82         int ret;
  83         size_t acc_size;
  84
  85         if (!gbo->bo.base.funcs)
  86                 gbo->bo.base.funcs = &drm_gem_vram_object_funcs;
  87
  88         ret = drm_gem_object_init(dev, &gbo->bo.base, size);
  89         if (ret)
  90                 return ret;
  91
  92         acc_size = ttm_bo_dma_acc_size(bdev, size, sizeof(*gbo));
  93
  94         gbo->bo.bdev = bdev;
  95         drm_gem_vram_placement(gbo, TTM_PL_FLAG_VRAM | TTM_PL_FLAG_SYSTEM);
  96
  97         ret = ttm_bo_init(bdev, &gbo->bo, size, ttm_bo_type_device,
  98                           &gbo->placement, pg_align, interruptible, acc_size,
  99                           NULL, NULL, ttm_buffer_object_destroy);
 100         if (ret)
 101                 goto err_drm_gem_object_release;
 102
 103         return 0;
 104
 105 err_drm_gem_object_release:
 106         drm_gem_object_release(&gbo->bo.base);
 107         return ret;
 108 }
 109
 110 /**
 111  * drm_gem_vram_create() - Creates a VRAM-backed GEM object
 112  * @dev:                the DRM device
 113  * @bdev:               the TTM BO device backing the object
 114  * @size:               the buffer size in bytes
 115  * @pg_align:           the buffer's alignment in multiples of the page size
 116  * @interruptible:      sleep interruptible if waiting for memory
 117  *
 118  * Returns:
 119  * A new instance of &struct drm_gem_vram_object on success, or
 120  * an ERR_PTR()-encoded error code otherwise.
 121  */
 122 struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
 123                                                 struct ttm_bo_device *bdev,
 124                                                 size_t size,
 125                                                 unsigned long pg_align,
 126                                                 bool interruptible)
 127 {
 128         struct drm_gem_vram_object *gbo;
 129         int ret;
 130
 131         gbo = kzalloc(sizeof(*gbo), GFP_KERNEL);
 132         if (!gbo)
 133                 return ERR_PTR(-ENOMEM);
 134
 135         ret = drm_gem_vram_init(dev, bdev, gbo, size, pg_align, interruptible);
 136         if (ret < 0)
 137                 goto err_kfree;
 138
 139         return gbo;
 140
 141 err_kfree:
 142         kfree(gbo);
 143         return ERR_PTR(ret);
 144 }
 145 EXPORT_SYMBOL(drm_gem_vram_create);
 146
 147 /**
 148  * drm_gem_vram_put() - Releases a reference to a VRAM-backed GEM object
 149  * @gbo:        the GEM VRAM object
 150  *
 151  * See ttm_bo_put() for more information.
 152  */
 153 void drm_gem_vram_put(struct drm_gem_vram_object *gbo)
 154 {
 155         ttm_bo_put(&gbo->bo);
 156 }
 157 EXPORT_SYMBOL(drm_gem_vram_put);
 158
 159 /**
 160  * drm_gem_vram_mmap_offset() - Returns a GEM VRAM object's mmap offset
 161  * @gbo:        the GEM VRAM object
 162  *
 163  * See drm_vma_node_offset_addr() for more information.
 164  *
 165  * Returns:
 166  * The buffer object's offset for userspace mappings on success, or
 167  * 0 if no offset is allocated.
 168  */
 169 u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo)
 170 {
 171         return drm_vma_node_offset_addr(&gbo->bo.base.vma_node);
 172 }
 173 EXPORT_SYMBOL(drm_gem_vram_mmap_offset);
 174
 175 /**
 176  * drm_gem_vram_offset() - \
 177         Returns a GEM VRAM object's offset in video memory
 178  * @gbo:        the GEM VRAM object
 179  *
 180  * This function returns the buffer object's offset in the device's video
 181  * memory. The buffer object has to be pinned to %TTM_PL_VRAM.
 182  *
 183  * Returns:
 184  * The buffer object's offset in video memory on success, or
 185  * a negative errno code otherwise.
 186  */
 187 s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo)
 188 {
 189         if (WARN_ON_ONCE(!gbo->pin_count))
 190                 return (s64)-ENODEV;
 191         return gbo->bo.offset;
 192 }
 193 EXPORT_SYMBOL(drm_gem_vram_offset);
 194
 195 /**
 196  * drm_gem_vram_pin() - Pins a GEM VRAM object in a region.
 197  * @gbo:        the GEM VRAM object
 198  * @pl_flag:    a bitmask of possible memory regions
 199  *
 200  * Pinning a buffer object ensures that it is not evicted from
 201  * a memory region. A pinned buffer object has to be unpinned before
 202  * it can be pinned to another region. If the pl_flag argument is 0,
 203  * the buffer is pinned at its current location (video RAM or system
 204  * memory).
 205  *
 206  * Returns:
 207  * 0 on success, or
 208  * a negative error code otherwise.
 209  */
 210 int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag)
 211 {
 212         int i, ret;
 213         struct ttm_operation_ctx ctx = { false, false };
 214
 215         ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
 216         if (ret < 0)
 217                 return ret;
 218
 219         if (gbo->pin_count)
 220                 goto out;
 221
 222         if (pl_flag)
 223                 drm_gem_vram_placement(gbo, pl_flag);
 224
 225         for (i = 0; i < gbo->placement.num_placement; ++i)
 226                 gbo->placements[i].flags |= TTM_PL_FLAG_NO_EVICT;
 227
 228         ret = ttm_bo_validate(&gbo->bo, &gbo->placement, &ctx);
 229         if (ret < 0)
 230                 goto err_ttm_bo_unreserve;
 231
 232 out:
 233         ++gbo->pin_count;
 234         ttm_bo_unreserve(&gbo->bo);
 235
 236         return 0;
 237
 238 err_ttm_bo_unreserve:
 239         ttm_bo_unreserve(&gbo->bo);
 240         return ret;
 241 }
 242 EXPORT_SYMBOL(drm_gem_vram_pin);
 243
 244 /**
 245  * drm_gem_vram_unpin() - Unpins a GEM VRAM object
 246  * @gbo:        the GEM VRAM object
 247  *
 248  * Returns:
 249  * 0 on success, or
 250  * a negative error code otherwise.
 251  */
 252 int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo)
 253 {
 254         int i, ret;
 255         struct ttm_operation_ctx ctx = { false, false };
 256
 257         ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
 258         if (ret < 0)
 259                 return ret;
 260
 261         if (WARN_ON_ONCE(!gbo->pin_count))
 262                 goto out;
 263
 264         --gbo->pin_count;
 265         if (gbo->pin_count)
 266                 goto out;
 267
 268         for (i = 0; i < gbo->placement.num_placement ; ++i)
 269                 gbo->placements[i].flags &= ~TTM_PL_FLAG_NO_EVICT;
 270
 271         ret = ttm_bo_validate(&gbo->bo, &gbo->placement, &ctx);
 272         if (ret < 0)
 273                 goto err_ttm_bo_unreserve;
 274
 275 out:
 276         ttm_bo_unreserve(&gbo->bo);
 277
 278         return 0;
 279
 280 err_ttm_bo_unreserve:
 281         ttm_bo_unreserve(&gbo->bo);
 282         return ret;
 283 }
 284 EXPORT_SYMBOL(drm_gem_vram_unpin);
 285
 286 /**
 287  * drm_gem_vram_kmap() - Maps a GEM VRAM object into kernel address space
 288  * @gbo:        the GEM VRAM object
 289  * @map:        establish a mapping if necessary
 290  * @is_iomem:   returns true if the mapped memory is I/O memory, or false \
 291         otherwise; can be NULL
 292  *
 293  * This function maps the buffer object into the kernel's address space
 294  * or returns the current mapping. If the parameter map is false, the
 295  * function only queries the current mapping, but does not establish a
 296  * new one.
 297  *
 298  * Returns:
 299  * The buffers virtual address if mapped, or
 300  * NULL if not mapped, or
 301  * an ERR_PTR()-encoded error code otherwise.
 302  */
 303 void *drm_gem_vram_kmap(struct drm_gem_vram_object *gbo, bool map,
 304                         bool *is_iomem)
 305 {
 306         int ret;
 307         struct ttm_bo_kmap_obj *kmap = &gbo->kmap;
 308
 309         if (kmap->virtual || !map)
 310                 goto out;
 311
 312         ret = ttm_bo_kmap(&gbo->bo, 0, gbo->bo.num_pages, kmap);
 313         if (ret)
 314                 return ERR_PTR(ret);
 315
 316 out:
 317         if (!is_iomem)
 318                 return kmap->virtual;
 319         if (!kmap->virtual) {
 320                 *is_iomem = false;
 321                 return NULL;
 322         }
 323         return ttm_kmap_obj_virtual(kmap, is_iomem);
 324 }
 325 EXPORT_SYMBOL(drm_gem_vram_kmap);
 326
 327 /**
 328  * drm_gem_vram_kunmap() - Unmaps a GEM VRAM object
 329  * @gbo:        the GEM VRAM object
 330  */
 331 void drm_gem_vram_kunmap(struct drm_gem_vram_object *gbo)
 332 {
 333         struct ttm_bo_kmap_obj *kmap = &gbo->kmap;
 334
 335         if (!kmap->virtual)
 336                 return;
 337
 338         ttm_bo_kunmap(kmap);
 339         kmap->virtual = NULL;
 340 }
 341 EXPORT_SYMBOL(drm_gem_vram_kunmap);
 342
 343 /**
 344  * drm_gem_vram_fill_create_dumb() - \
 345         Helper for implementing &struct drm_driver.dumb_create
 346  * @file:               the DRM file
 347  * @dev:                the DRM device
 348  * @bdev:               the TTM BO device managing the buffer object
 349  * @pg_align:           the buffer's alignment in multiples of the page size
 350  * @interruptible:      sleep interruptible if waiting for memory
 351  * @args:               the arguments as provided to \
 352                                 &struct drm_driver.dumb_create
 353  *
 354  * This helper function fills &struct drm_mode_create_dumb, which is used
 355  * by &struct drm_driver.dumb_create. Implementations of this interface
 356  * should forwards their arguments to this helper, plus the driver-specific
 357  * parameters.
 358  *
 359  * Returns:
 360  * 0 on success, or
 361  * a negative error code otherwise.
 362  */
 363 int drm_gem_vram_fill_create_dumb(struct drm_file *file,
 364                                   struct drm_device *dev,
 365                                   struct ttm_bo_device *bdev,
 366                                   unsigned long pg_align,
 367                                   bool interruptible,
 368                                   struct drm_mode_create_dumb *args)
 369 {
 370         size_t pitch, size;
 371         struct drm_gem_vram_object *gbo;
 372         int ret;
 373         u32 handle;
 374
 375         pitch = args->width * ((args->bpp + 7) / 8);
 376         size = pitch * args->height;
 377
 378         size = roundup(size, PAGE_SIZE);
 379         if (!size)
 380                 return -EINVAL;
 381
 382         gbo = drm_gem_vram_create(dev, bdev, size, pg_align, interruptible);
 383         if (IS_ERR(gbo))
 384                 return PTR_ERR(gbo);
 385
 386         ret = drm_gem_handle_create(file, &gbo->bo.base, &handle);
 387         if (ret)
 388                 goto err_drm_gem_object_put_unlocked;
 389
 390         drm_gem_object_put_unlocked(&gbo->bo.base);
 391
 392         args->pitch = pitch;
 393         args->size = size;
 394         args->handle = handle;
 395
 396         return 0;
 397
 398 err_drm_gem_object_put_unlocked:
 399         drm_gem_object_put_unlocked(&gbo->bo.base);
 400         return ret;
 401 }
 402 EXPORT_SYMBOL(drm_gem_vram_fill_create_dumb);
 403
 404 /*
 405  * Helpers for struct ttm_bo_driver
 406  */
 407
 408 static bool drm_is_gem_vram(struct ttm_buffer_object *bo)
 409 {
 410         return (bo->destroy == ttm_buffer_object_destroy);
 411 }
 412
 413 /**
 414  * drm_gem_vram_bo_driver_evict_flags() - \
 415         Implements &struct ttm_bo_driver.evict_flags
 416  * @bo: TTM buffer object. Refers to &struct drm_gem_vram_object.bo
 417  * @pl: TTM placement information.
 418  */
 419 void drm_gem_vram_bo_driver_evict_flags(struct ttm_buffer_object *bo,
 420                                         struct ttm_placement *pl)
 421 {
 422         struct drm_gem_vram_object *gbo;
 423
 424         /* TTM may pass BOs that are not GEM VRAM BOs. */
 425         if (!drm_is_gem_vram(bo))
 426                 return;
 427
 428         gbo = drm_gem_vram_of_bo(bo);
 429         drm_gem_vram_placement(gbo, TTM_PL_FLAG_SYSTEM);
 430         *pl = gbo->placement;
 431 }
 432 EXPORT_SYMBOL(drm_gem_vram_bo_driver_evict_flags);
 433
 434 /**
 435  * drm_gem_vram_bo_driver_verify_access() - \
 436         Implements &struct ttm_bo_driver.verify_access
 437  * @bo:         TTM buffer object. Refers to &struct drm_gem_vram_object.bo
 438  * @filp:       File pointer.
 439  *
 440  * Returns:
 441  * 0 on success, or
 442  * a negative errno code otherwise.
 443  */
 444 int drm_gem_vram_bo_driver_verify_access(struct ttm_buffer_object *bo,
 445                                          struct file *filp)
 446 {
 447         struct drm_gem_vram_object *gbo = drm_gem_vram_of_bo(bo);
 448
 449         return drm_vma_node_verify_access(&gbo->bo.base.vma_node,
 450                                           filp->private_data);
 451 }
 452 EXPORT_SYMBOL(drm_gem_vram_bo_driver_verify_access);
 453
 454 /*
 455  * drm_gem_vram_mm_funcs - Functions for &struct drm_vram_mm
 456  *
 457  * Most users of @struct drm_gem_vram_object will also use
 458  * @struct drm_vram_mm. This instance of &struct drm_vram_mm_funcs
 459  * can be used to connect both.
 460  */
 461 const struct drm_vram_mm_funcs drm_gem_vram_mm_funcs = {
 462         .evict_flags = drm_gem_vram_bo_driver_evict_flags,
 463         .verify_access = drm_gem_vram_bo_driver_verify_access
 464 };
 465 EXPORT_SYMBOL(drm_gem_vram_mm_funcs);
 466
 467 /*
 468  * Helpers for struct drm_gem_object_funcs
 469  */
 470
 471 /**
 472  * drm_gem_vram_object_free() - \
 473         Implements &struct drm_gem_object_funcs.free
 474  * @gem:       GEM object. Refers to &struct drm_gem_vram_object.gem
 475  */
 476 static void drm_gem_vram_object_free(struct drm_gem_object *gem)
 477 {
 478         struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 479
 480         drm_gem_vram_put(gbo);
 481 }
 482
 483 /*
 484  * Helpers for dump buffers
 485  */
 486
 487 /**
 488  * drm_gem_vram_driver_create_dumb() - \
 489         Implements &struct drm_driver.dumb_create
 490  * @file:               the DRM file
 491  * @dev:                the DRM device
 492  * @args:               the arguments as provided to \
 493                                 &struct drm_driver.dumb_create
 494  *
 495  * This function requires the driver to use @drm_device.vram_mm for its
 496  * instance of VRAM MM.
 497  *
 498  * Returns:
 499  * 0 on success, or
 500  * a negative error code otherwise.
 501  */
 502 int drm_gem_vram_driver_dumb_create(struct drm_file *file,
 503                                     struct drm_device *dev,
 504                                     struct drm_mode_create_dumb *args)
 505 {
 506         if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized"))
 507                 return -EINVAL;
 508
 509         return drm_gem_vram_fill_create_dumb(file, dev, &dev->vram_mm->bdev, 0,
 510                                              false, args);
 511 }
 512 EXPORT_SYMBOL(drm_gem_vram_driver_dumb_create);
 513
 514 /**
 515  * drm_gem_vram_driver_dumb_mmap_offset() - \
 516         Implements &struct drm_driver.dumb_mmap_offset
 517  * @file:       DRM file pointer.
 518  * @dev:        DRM device.
 519  * @handle:     GEM handle
 520  * @offset:     Returns the mapping's memory offset on success
 521  *
 522  * Returns:
 523  * 0 on success, or
 524  * a negative errno code otherwise.
 525  */
 526 int drm_gem_vram_driver_dumb_mmap_offset(struct drm_file *file,
 527                                          struct drm_device *dev,
 528                                          uint32_t handle, uint64_t *offset)
 529 {
 530         struct drm_gem_object *gem;
 531         struct drm_gem_vram_object *gbo;
 532
 533         gem = drm_gem_object_lookup(file, handle);
 534         if (!gem)
 535                 return -ENOENT;
 536
 537         gbo = drm_gem_vram_of_gem(gem);
 538         *offset = drm_gem_vram_mmap_offset(gbo);
 539
 540         drm_gem_object_put_unlocked(gem);
 541
 542         return 0;
 543 }
 544 EXPORT_SYMBOL(drm_gem_vram_driver_dumb_mmap_offset);
 545
 546 /*
 547  * PRIME helpers
 548  */
 549
 550 /**
 551  * drm_gem_vram_object_pin() - \
 552         Implements &struct drm_gem_object_funcs.pin
 553  * @gem:        The GEM object to pin
 554  *
 555  * Returns:
 556  * 0 on success, or
 557  * a negative errno code otherwise.
 558  */
 559 static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
 560 {
 561         struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 562
 563         /* Fbdev console emulation is the use case of these PRIME
 564          * helpers. This may involve updating a hardware buffer from
 565          * a shadow FB. We pin the buffer to it's current location
 566          * (either video RAM or system memory) to prevent it from
 567          * being relocated during the update operation. If you require
 568          * the buffer to be pinned to VRAM, implement a callback that
 569          * sets the flags accordingly.
 570          */
 571         return drm_gem_vram_pin(gbo, 0);
 572 }
 573
 574 /**
 575  * drm_gem_vram_object_unpin() - \
 576         Implements &struct drm_gem_object_funcs.unpin
 577  * @gem:        The GEM object to unpin
 578  */
 579 static void drm_gem_vram_object_unpin(struct drm_gem_object *gem)
 580 {
 581         struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 582
 583         drm_gem_vram_unpin(gbo);
 584 }
 585
 586 /**
 587  * drm_gem_vram_object_vmap() - \
 588         Implements &struct drm_gem_object_funcs.vmap
 589  * @gem:        The GEM object to map
 590  *
 591  * Returns:
 592  * The buffers virtual address on success, or
 593  * NULL otherwise.
 594  */
 595 static void *drm_gem_vram_object_vmap(struct drm_gem_object *gem)
 596 {
 597         struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 598         int ret;
 599         void *base;
 600
 601         ret = drm_gem_vram_pin(gbo, 0);
 602         if (ret)
 603                 return NULL;
 604         base = drm_gem_vram_kmap(gbo, true, NULL);
 605         if (IS_ERR(base)) {
 606                 drm_gem_vram_unpin(gbo);
 607                 return NULL;
 608         }
 609         return base;
 610 }
 611
 612 /**
 613  * drm_gem_vram_object_vunmap() - \
 614         Implements &struct drm_gem_object_funcs.vunmap
 615  * @gem:        The GEM object to unmap
 616  * @vaddr:      The mapping's base address
 617  */
 618 static void drm_gem_vram_object_vunmap(struct drm_gem_object *gem,
 619                                        void *vaddr)
 620 {
 621         struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 622
 623         drm_gem_vram_kunmap(gbo);
 624         drm_gem_vram_unpin(gbo);
 625 }
 626
 627 /*
 628  * GEM object funcs
 629  */
 630
 631 static const struct drm_gem_object_funcs drm_gem_vram_object_funcs = {
 632         .free   = drm_gem_vram_object_free,
 633         .pin    = drm_gem_vram_object_pin,
 634         .unpin  = drm_gem_vram_object_unpin,
 635         .vmap   = drm_gem_vram_object_vmap,
 636         .vunmap = drm_gem_vram_object_vunmap
 637 };