include/drm/ttm/ttm_bo_api.h

   1 /**************************************************************************
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  15  * next paragraph) shall be included in all copies or substantial portions
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  26  **************************************************************************/
  27 /*
  28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  29  */
  30
  31 #ifndef _TTM_BO_API_H_
  32 #define _TTM_BO_API_H_
  33
  34 #include <drm/drm_hashtab.h>
  35 #include <drm/drm_vma_manager.h>
  36 #include <linux/kref.h>
  37 #include <linux/list.h>
  38 #include <linux/wait.h>
  39 #include <linux/mutex.h>
  40 #include <linux/mm.h>
  41 #include <linux/bitmap.h>
  42 #include <linux/reservation.h>
  43
  44 struct ttm_bo_device;
  45
  46 struct drm_mm_node;
  47
  48 struct ttm_placement;
  49
  50 struct ttm_place;
  51
  52 /**
  53  * struct ttm_bus_placement
  54  *
  55  * @addr:               mapped virtual address
  56  * @base:               bus base address
  57  * @is_iomem:           is this io memory ?
  58  * @size:               size in byte
  59  * @offset:             offset from the base address
  60  * @io_reserved_vm:     The VM system has a refcount in @io_reserved_count
  61  * @io_reserved_count:  Refcounting the numbers of callers to ttm_mem_io_reserve
  62  *
  63  * Structure indicating the bus placement of an object.
  64  */
  65 struct ttm_bus_placement {
  66         void            *addr;
  67         phys_addr_t     base;
  68         unsigned long   size;
  69         unsigned long   offset;
  70         bool            is_iomem;
  71         bool            io_reserved_vm;
  72         uint64_t        io_reserved_count;
  73 };
  74
  75
  76 /**
  77  * struct ttm_mem_reg
  78  *
  79  * @mm_node: Memory manager node.
  80  * @size: Requested size of memory region.
  81  * @num_pages: Actual size of memory region in pages.
  82  * @page_alignment: Page alignment.
  83  * @placement: Placement flags.
  84  * @bus: Placement on io bus accessible to the CPU
  85  *
  86  * Structure indicating the placement and space resources used by a
  87  * buffer object.
  88  */
  89
  90 struct ttm_mem_reg {
  91         void *mm_node;
  92         unsigned long start;
  93         unsigned long size;
  94         unsigned long num_pages;
  95         uint32_t page_alignment;
  96         uint32_t mem_type;
  97         uint32_t placement;
  98         struct ttm_bus_placement bus;
  99 };
 100
 101 /**
 102  * enum ttm_bo_type
 103  *
 104  * @ttm_bo_type_device: These are 'normal' buffers that can
 105  * be mmapped by user space. Each of these bos occupy a slot in the
 106  * device address space, that can be used for normal vm operations.
 107  *
 108  * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
 109  * but they cannot be accessed from user-space. For kernel-only use.
 110  *
 111  * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another
 112  * driver.
 113  */
 114
 115 enum ttm_bo_type {
 116         ttm_bo_type_device,
 117         ttm_bo_type_kernel,
 118         ttm_bo_type_sg
 119 };
 120
 121 struct ttm_tt;
 122
 123 /**
 124  * struct ttm_buffer_object
 125  *
 126  * @bdev: Pointer to the buffer object device structure.
 127  * @type: The bo type.
 128  * @destroy: Destruction function. If NULL, kfree is used.
 129  * @num_pages: Actual number of pages.
 130  * @acc_size: Accounted size for this object.
 131  * @kref: Reference count of this buffer object. When this refcount reaches
 132  * zero, the object is put on the delayed delete list.
 133  * @list_kref: List reference count of this buffer object. This member is
 134  * used to avoid destruction while the buffer object is still on a list.
 135  * Lru lists may keep one refcount, the delayed delete list, and kref != 0
 136  * keeps one refcount. When this refcount reaches zero,
 137  * the object is destroyed.
 138  * @mem: structure describing current placement.
 139  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 140  * pinned in physical memory. If this behaviour is not desired, this member
 141  * holds a pointer to a persistent shmem object.
 142  * @ttm: TTM structure holding system pages.
 143  * @evicted: Whether the object was evicted without user-space knowing.
 144  * @cpu_writes: For synchronization. Number of cpu writers.
 145  * @lru: List head for the lru list.
 146  * @ddestroy: List head for the delayed destroy list.
 147  * @swap: List head for swap LRU list.
 148  * @moving: Fence set when BO is moving
 149  * @vma_node: Address space manager node.
 150  * @offset: The current GPU offset, which can have different meanings
 151  * depending on the memory type. For SYSTEM type memory, it should be 0.
 152  * @cur_placement: Hint of current placement.
 153  * @wu_mutex: Wait unreserved mutex.
 154  *
 155  * Base class for TTM buffer object, that deals with data placement and CPU
 156  * mappings. GPU mappings are really up to the driver, but for simpler GPUs
 157  * the driver can usually use the placement offset @offset directly as the
 158  * GPU virtual address. For drivers implementing multiple
 159  * GPU memory manager contexts, the driver should manage the address space
 160  * in these contexts separately and use these objects to get the correct
 161  * placement and caching for these GPU maps. This makes it possible to use
 162  * these objects for even quite elaborate memory management schemes.
 163  * The destroy member, the API visibility of this object makes it possible
 164  * to derive driver specific types.
 165  */
 166
 167 struct ttm_buffer_object {
 168         /**
 169          * Members constant at init.
 170          */
 171
 172         struct ttm_bo_global *glob;
 173         struct ttm_bo_device *bdev;
 174         enum ttm_bo_type type;
 175         void (*destroy) (struct ttm_buffer_object *);
 176         unsigned long num_pages;
 177         size_t acc_size;
 178
 179         /**
 180         * Members not needing protection.
 181         */
 182
 183         struct kref kref;
 184         struct kref list_kref;
 185
 186         /**
 187          * Members protected by the bo::resv::reserved lock.
 188          */
 189
 190         struct ttm_mem_reg mem;
 191         struct file *persistent_swap_storage;
 192         struct ttm_tt *ttm;
 193         bool evicted;
 194
 195         /**
 196          * Members protected by the bo::reserved lock only when written to.
 197          */
 198
 199         atomic_t cpu_writers;
 200
 201         /**
 202          * Members protected by the bdev::lru_lock.
 203          */
 204
 205         struct list_head lru;
 206         struct list_head ddestroy;
 207         struct list_head swap;
 208         struct list_head io_reserve_lru;
 209
 210         /**
 211          * Members protected by a bo reservation.
 212          */
 213
 214         struct dma_fence *moving;
 215
 216         struct drm_vma_offset_node vma_node;
 217
 218         unsigned priority;
 219
 220         /**
 221          * Special members that are protected by the reserve lock
 222          * and the bo::lock when written to. Can be read with
 223          * either of these locks held.
 224          */
 225
 226         uint64_t offset; /* GPU address space is independent of CPU word size */
 227
 228         struct sg_table *sg;
 229
 230         struct reservation_object *resv;
 231         struct reservation_object ttm_resv;
 232         struct mutex wu_mutex;
 233 };
 234
 235 /**
 236  * struct ttm_bo_kmap_obj
 237  *
 238  * @virtual: The current kernel virtual address.
 239  * @page: The page when kmap'ing a single page.
 240  * @bo_kmap_type: Type of bo_kmap.
 241  *
 242  * Object describing a kernel mapping. Since a TTM bo may be located
 243  * in various memory types with various caching policies, the
 244  * mapping can either be an ioremap, a vmap, a kmap or part of a
 245  * premapped region.
 246  */
 247
 248 #define TTM_BO_MAP_IOMEM_MASK 0x80
 249 struct ttm_bo_kmap_obj {
 250         void *virtual;
 251         struct page *page;
 252         enum {
 253                 ttm_bo_map_iomap        = 1 | TTM_BO_MAP_IOMEM_MASK,
 254                 ttm_bo_map_vmap         = 2,
 255                 ttm_bo_map_kmap         = 3,
 256                 ttm_bo_map_premapped    = 4 | TTM_BO_MAP_IOMEM_MASK,
 257         } bo_kmap_type;
 258         struct ttm_buffer_object *bo;
 259 };
 260
 261 /**
 262  * struct ttm_operation_ctx
 263  *
 264  * @interruptible: Sleep interruptible if sleeping.
 265  * @no_wait_gpu: Return immediately if the GPU is busy.
 266  * @allow_reserved_eviction: Allow eviction of reserved BOs.
 267  * @resv: Reservation object to allow reserved evictions with.
 268  *
 269  * Context for TTM operations like changing buffer placement or general memory
 270  * allocation.
 271  */
 272 struct ttm_operation_ctx {
 273         bool interruptible;
 274         bool no_wait_gpu;
 275         bool allow_reserved_eviction;
 276         struct reservation_object *resv;
 277         uint64_t bytes_moved;
 278 };
 279
 280 /**
 281  * ttm_bo_reference - reference a struct ttm_buffer_object
 282  *
 283  * @bo: The buffer object.
 284  *
 285  * Returns a refcounted pointer to a buffer object.
 286  */
 287
 288 static inline struct ttm_buffer_object *
 289 ttm_bo_reference(struct ttm_buffer_object *bo)
 290 {
 291         kref_get(&bo->kref);
 292         return bo;
 293 }
 294
 295 /**
 296  * ttm_bo_wait - wait for buffer idle.
 297  *
 298  * @bo:  The buffer object.
 299  * @interruptible:  Use interruptible wait.
 300  * @no_wait:  Return immediately if buffer is busy.
 301  *
 302  * This function must be called with the bo::mutex held, and makes
 303  * sure any previous rendering to the buffer is completed.
 304  * Note: It might be necessary to block validations before the
 305  * wait by reserving the buffer.
 306  * Returns -EBUSY if no_wait is true and the buffer is busy.
 307  * Returns -ERESTARTSYS if interrupted by a signal.
 308  */
 309 int ttm_bo_wait(struct ttm_buffer_object *bo, bool interruptible, bool no_wait);
 310
 311 /**
 312  * ttm_bo_mem_compat - Check if proposed placement is compatible with a bo
 313  *
 314  * @placement:  Return immediately if buffer is busy.
 315  * @mem:  The struct ttm_mem_reg indicating the region where the bo resides
 316  * @new_flags: Describes compatible placement found
 317  *
 318  * Returns true if the placement is compatible
 319  */
 320 bool ttm_bo_mem_compat(struct ttm_placement *placement, struct ttm_mem_reg *mem,
 321                        uint32_t *new_flags);
 322
 323 /**
 324  * ttm_bo_validate
 325  *
 326  * @bo: The buffer object.
 327  * @placement: Proposed placement for the buffer object.
 328  * @ctx: validation parameters.
 329  *
 330  * Changes placement and caching policy of the buffer object
 331  * according proposed placement.
 332  * Returns
 333  * -EINVAL on invalid proposed placement.
 334  * -ENOMEM on out-of-memory condition.
 335  * -EBUSY if no_wait is true and buffer busy.
 336  * -ERESTARTSYS if interrupted by a signal.
 337  */
 338 int ttm_bo_validate(struct ttm_buffer_object *bo,
 339                     struct ttm_placement *placement,
 340                     struct ttm_operation_ctx *ctx);
 341
 342 /**
 343  * ttm_bo_unref
 344  *
 345  * @bo: The buffer object.
 346  *
 347  * Unreference and clear a pointer to a buffer object.
 348  */
 349 void ttm_bo_unref(struct ttm_buffer_object **bo);
 350
 351 /**
 352  * ttm_bo_add_to_lru
 353  *
 354  * @bo: The buffer object.
 355  *
 356  * Add this bo to the relevant mem type lru and, if it's backed by
 357  * system pages (ttms) to the swap list.
 358  * This function must be called with struct ttm_bo_global::lru_lock held, and
 359  * is typically called immediately prior to unreserving a bo.
 360  */
 361 void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
 362
 363 /**
 364  * ttm_bo_del_from_lru
 365  *
 366  * @bo: The buffer object.
 367  *
 368  * Remove this bo from all lru lists used to lookup and reserve an object.
 369  * This function must be called with struct ttm_bo_global::lru_lock held,
 370  * and is usually called just immediately after the bo has been reserved to
 371  * avoid recursive reservation from lru lists.
 372  */
 373 void ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
 374
 375 /**
 376  * ttm_bo_move_to_lru_tail
 377  *
 378  * @bo: The buffer object.
 379  *
 380  * Move this BO to the tail of all lru lists used to lookup and reserve an
 381  * object. This function must be called with struct ttm_bo_global::lru_lock
 382  * held, and is used to make a BO less likely to be considered for eviction.
 383  */
 384 void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo);
 385
 386 /**
 387  * ttm_bo_lock_delayed_workqueue
 388  *
 389  * Prevent the delayed workqueue from running.
 390  * Returns
 391  * True if the workqueue was queued at the time
 392  */
 393 int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
 394
 395 /**
 396  * ttm_bo_unlock_delayed_workqueue
 397  *
 398  * Allows the delayed workqueue to run.
 399  */
 400 void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev, int resched);
 401
 402 /**
 403  * ttm_bo_eviction_valuable
 404  *
 405  * @bo: The buffer object to evict
 406  * @place: the placement we need to make room for
 407  *
 408  * Check if it is valuable to evict the BO to make room for the given placement.
 409  */
 410 bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
 411                               const struct ttm_place *place);
 412
 413 /**
 414  * ttm_bo_synccpu_write_grab
 415  *
 416  * @bo: The buffer object:
 417  * @no_wait: Return immediately if buffer is busy.
 418  *
 419  * Synchronizes a buffer object for CPU RW access. This means
 420  * command submission that affects the buffer will return -EBUSY
 421  * until ttm_bo_synccpu_write_release is called.
 422  *
 423  * Returns
 424  * -EBUSY if the buffer is busy and no_wait is true.
 425  * -ERESTARTSYS if interrupted by a signal.
 426  */
 427 int ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
 428
 429 /**
 430  * ttm_bo_synccpu_write_release:
 431  *
 432  * @bo : The buffer object.
 433  *
 434  * Releases a synccpu lock.
 435  */
 436 void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
 437
 438 /**
 439  * ttm_bo_acc_size
 440  *
 441  * @bdev: Pointer to a ttm_bo_device struct.
 442  * @bo_size: size of the buffer object in byte.
 443  * @struct_size: size of the structure holding buffer object datas
 444  *
 445  * Returns size to account for a buffer object
 446  */
 447 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
 448                        unsigned long bo_size,
 449                        unsigned struct_size);
 450 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
 451                            unsigned long bo_size,
 452                            unsigned struct_size);
 453
 454 /**
 455  * ttm_bo_init_reserved
 456  *
 457  * @bdev: Pointer to a ttm_bo_device struct.
 458  * @bo: Pointer to a ttm_buffer_object to be initialized.
 459  * @size: Requested size of buffer object.
 460  * @type: Requested type of buffer object.
 461  * @flags: Initial placement flags.
 462  * @page_alignment: Data alignment in pages.
 463  * @ctx: TTM operation context for memory allocation.
 464  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 465  * pinned in physical memory. If this behaviour is not desired, this member
 466  * holds a pointer to a persistent shmem object. Typically, this would
 467  * point to the shmem object backing a GEM object if TTM is used to back a
 468  * GEM user interface.
 469  * @acc_size: Accounted size for this object.
 470  * @resv: Pointer to a reservation_object, or NULL to let ttm allocate one.
 471  * @destroy: Destroy function. Use NULL for kfree().
 472  *
 473  * This function initializes a pre-allocated struct ttm_buffer_object.
 474  * As this object may be part of a larger structure, this function,
 475  * together with the @destroy function,
 476  * enables driver-specific objects derived from a ttm_buffer_object.
 477  *
 478  * On successful return, the caller owns an object kref to @bo. The kref and
 479  * list_kref are usually set to 1, but note that in some situations, other
 480  * tasks may already be holding references to @bo as well.
 481  * Furthermore, if resv == NULL, the buffer's reservation lock will be held,
 482  * and it is the caller's responsibility to call ttm_bo_unreserve.
 483  *
 484  * If a failure occurs, the function will call the @destroy function, or
 485  * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
 486  * illegal and will likely cause memory corruption.
 487  *
 488  * Returns
 489  * -ENOMEM: Out of memory.
 490  * -EINVAL: Invalid placement flags.
 491  * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
 492  */
 493
 494 int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
 495                          struct ttm_buffer_object *bo,
 496                          unsigned long size,
 497                          enum ttm_bo_type type,
 498                          struct ttm_placement *placement,
 499                          uint32_t page_alignment,
 500                          struct ttm_operation_ctx *ctx,
 501                          struct file *persistent_swap_storage,
 502                          size_t acc_size,
 503                          struct sg_table *sg,
 504                          struct reservation_object *resv,
 505                          void (*destroy) (struct ttm_buffer_object *));
 506
 507 /**
 508  * ttm_bo_init
 509  *
 510  * @bdev: Pointer to a ttm_bo_device struct.
 511  * @bo: Pointer to a ttm_buffer_object to be initialized.
 512  * @size: Requested size of buffer object.
 513  * @type: Requested type of buffer object.
 514  * @flags: Initial placement flags.
 515  * @page_alignment: Data alignment in pages.
 516  * @interruptible: If needing to sleep to wait for GPU resources,
 517  * sleep interruptible.
 518  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 519  * pinned in physical memory. If this behaviour is not desired, this member
 520  * holds a pointer to a persistent shmem object. Typically, this would
 521  * point to the shmem object backing a GEM object if TTM is used to back a
 522  * GEM user interface.
 523  * @acc_size: Accounted size for this object.
 524  * @resv: Pointer to a reservation_object, or NULL to let ttm allocate one.
 525  * @destroy: Destroy function. Use NULL for kfree().
 526  *
 527  * This function initializes a pre-allocated struct ttm_buffer_object.
 528  * As this object may be part of a larger structure, this function,
 529  * together with the @destroy function,
 530  * enables driver-specific objects derived from a ttm_buffer_object.
 531  *
 532  * On successful return, the caller owns an object kref to @bo. The kref and
 533  * list_kref are usually set to 1, but note that in some situations, other
 534  * tasks may already be holding references to @bo as well.
 535  *
 536  * If a failure occurs, the function will call the @destroy function, or
 537  * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
 538  * illegal and will likely cause memory corruption.
 539  *
 540  * Returns
 541  * -ENOMEM: Out of memory.
 542  * -EINVAL: Invalid placement flags.
 543  * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
 544  */
 545 int ttm_bo_init(struct ttm_bo_device *bdev, struct ttm_buffer_object *bo,
 546                 unsigned long size, enum ttm_bo_type type,
 547                 struct ttm_placement *placement,
 548                 uint32_t page_alignment, bool interrubtible,
 549                 struct file *persistent_swap_storage, size_t acc_size,
 550                 struct sg_table *sg, struct reservation_object *resv,
 551                 void (*destroy) (struct ttm_buffer_object *));
 552
 553 /**
 554  * ttm_bo_create
 555  *
 556  * @bdev: Pointer to a ttm_bo_device struct.
 557  * @size: Requested size of buffer object.
 558  * @type: Requested type of buffer object.
 559  * @placement: Initial placement.
 560  * @page_alignment: Data alignment in pages.
 561  * @interruptible: If needing to sleep while waiting for GPU resources,
 562  * sleep interruptible.
 563  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 564  * pinned in physical memory. If this behaviour is not desired, this member
 565  * holds a pointer to a persistent shmem object. Typically, this would
 566  * point to the shmem object backing a GEM object if TTM is used to back a
 567  * GEM user interface.
 568  * @p_bo: On successful completion *p_bo points to the created object.
 569  *
 570  * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
 571  * on that object. The destroy function is set to kfree().
 572  * Returns
 573  * -ENOMEM: Out of memory.
 574  * -EINVAL: Invalid placement flags.
 575  * -ERESTARTSYS: Interrupted by signal while waiting for resources.
 576  */
 577 int ttm_bo_create(struct ttm_bo_device *bdev, unsigned long size,
 578                   enum ttm_bo_type type, struct ttm_placement *placement,
 579                   uint32_t page_alignment, bool interruptible,
 580                   struct file *persistent_swap_storage,
 581                   struct ttm_buffer_object **p_bo);
 582
 583 /**
 584  * ttm_bo_init_mm
 585  *
 586  * @bdev: Pointer to a ttm_bo_device struct.
 587  * @mem_type: The memory type.
 588  * @p_size: size managed area in pages.
 589  *
 590  * Initialize a manager for a given memory type.
 591  * Note: if part of driver firstopen, it must be protected from a
 592  * potentially racing lastclose.
 593  * Returns:
 594  * -EINVAL: invalid size or memory type.
 595  * -ENOMEM: Not enough memory.
 596  * May also return driver-specified errors.
 597  */
 598 int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
 599                    unsigned long p_size);
 600
 601 /**
 602  * ttm_bo_clean_mm
 603  *
 604  * @bdev: Pointer to a ttm_bo_device struct.
 605  * @mem_type: The memory type.
 606  *
 607  * Take down a manager for a given memory type after first walking
 608  * the LRU list to evict any buffers left alive.
 609  *
 610  * Normally, this function is part of lastclose() or unload(), and at that
 611  * point there shouldn't be any buffers left created by user-space, since
 612  * there should've been removed by the file descriptor release() method.
 613  * However, before this function is run, make sure to signal all sync objects,
 614  * and verify that the delayed delete queue is empty. The driver must also
 615  * make sure that there are no NO_EVICT buffers present in this memory type
 616  * when the call is made.
 617  *
 618  * If this function is part of a VT switch, the caller must make sure that
 619  * there are no appications currently validating buffers before this
 620  * function is called. The caller can do that by first taking the
 621  * struct ttm_bo_device::ttm_lock in write mode.
 622  *
 623  * Returns:
 624  * -EINVAL: invalid or uninitialized memory type.
 625  * -EBUSY: There are still buffers left in this memory type.
 626  */
 627 int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
 628
 629 /**
 630  * ttm_bo_evict_mm
 631  *
 632  * @bdev: Pointer to a ttm_bo_device struct.
 633  * @mem_type: The memory type.
 634  *
 635  * Evicts all buffers on the lru list of the memory type.
 636  * This is normally part of a VT switch or an
 637  * out-of-memory-space-due-to-fragmentation handler.
 638  * The caller must make sure that there are no other processes
 639  * currently validating buffers, and can do that by taking the
 640  * struct ttm_bo_device::ttm_lock in write mode.
 641  *
 642  * Returns:
 643  * -EINVAL: Invalid or uninitialized memory type.
 644  * -ERESTARTSYS: The call was interrupted by a signal while waiting to
 645  * evict a buffer.
 646  */
 647 int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
 648
 649 /**
 650  * ttm_kmap_obj_virtual
 651  *
 652  * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
 653  * @is_iomem: Pointer to an integer that on return indicates 1 if the
 654  * virtual map is io memory, 0 if normal memory.
 655  *
 656  * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
 657  * If *is_iomem is 1 on return, the virtual address points to an io memory area,
 658  * that should strictly be accessed by the iowriteXX() and similar functions.
 659  */
 660 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
 661                                          bool *is_iomem)
 662 {
 663         *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
 664         return map->virtual;
 665 }
 666
 667 /**
 668  * ttm_bo_kmap
 669  *
 670  * @bo: The buffer object.
 671  * @start_page: The first page to map.
 672  * @num_pages: Number of pages to map.
 673  * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
 674  *
 675  * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
 676  * data in the buffer object. The ttm_kmap_obj_virtual function can then be
 677  * used to obtain a virtual address to the data.
 678  *
 679  * Returns
 680  * -ENOMEM: Out of memory.
 681  * -EINVAL: Invalid range.
 682  */
 683 int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
 684                 unsigned long num_pages, struct ttm_bo_kmap_obj *map);
 685
 686 /**
 687  * ttm_bo_kunmap
 688  *
 689  * @map: Object describing the map to unmap.
 690  *
 691  * Unmaps a kernel map set up by ttm_bo_kmap.
 692  */
 693 void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
 694
 695 /**
 696  * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
 697  *
 698  * @vma:       vma as input from the fbdev mmap method.
 699  * @bo:        The bo backing the address space. The address space will
 700  * have the same size as the bo, and start at offset 0.
 701  *
 702  * This function is intended to be called by the fbdev mmap method
 703  * if the fbdev address space is to be backed by a bo.
 704  */
 705 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo);
 706
 707 /**
 708  * ttm_bo_mmap - mmap out of the ttm device address space.
 709  *
 710  * @filp:      filp as input from the mmap method.
 711  * @vma:       vma as input from the mmap method.
 712  * @bdev:      Pointer to the ttm_bo_device with the address space manager.
 713  *
 714  * This function is intended to be called by the device mmap method.
 715  * if the device address space is to be backed by the bo manager.
 716  */
 717 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 718                 struct ttm_bo_device *bdev);
 719
 720 /**
 721  * ttm_bo_io
 722  *
 723  * @bdev:      Pointer to the struct ttm_bo_device.
 724  * @filp:      Pointer to the struct file attempting to read / write.
 725  * @wbuf:      User-space pointer to address of buffer to write. NULL on read.
 726  * @rbuf:      User-space pointer to address of buffer to read into.
 727  * Null on write.
 728  * @count:     Number of bytes to read / write.
 729  * @f_pos:     Pointer to current file position.
 730  * @write:     1 for read, 0 for write.
 731  *
 732  * This function implements read / write into ttm buffer objects, and is
 733  * intended to
 734  * be called from the fops::read and fops::write method.
 735  * Returns:
 736  * See man (2) write, man(2) read. In particular,
 737  * the function may return -ERESTARTSYS if
 738  * interrupted by a signal.
 739  */
 740 ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
 741                   const char __user *wbuf, char __user *rbuf,
 742                   size_t count, loff_t *f_pos, bool write);
 743
 744 int ttm_bo_swapout(struct ttm_bo_global *glob,
 745                         struct ttm_operation_ctx *ctx);
 746 void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
 747 int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo);
 748 #endif