include/drm/ttm/ttm_bo_api.h

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