include/drm/ttm/ttm_bo_api.h

   1 /**************************************************************************
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   3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   4  * All Rights Reserved.
   5  *
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  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
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  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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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 <linux/kref.h>
  36 #include <linux/list.h>
  37 #include <linux/wait.h>
  38 #include <linux/mutex.h>
  39 #include <linux/mm.h>
  40 #include <linux/rbtree.h>
  41 #include <linux/bitmap.h>
  42
  43 struct ttm_bo_device;
  44
  45 struct drm_mm_node;
  46
  47
  48 /**
  49  * struct ttm_placement
  50  *
  51  * @fpfn:               first valid page frame number to put the object
  52  * @lpfn:               last valid page frame number to put the object
  53  * @num_placement:      number of preferred placements
  54  * @placement:          preferred placements
  55  * @num_busy_placement: number of preferred placements when need to evict buffer
  56  * @busy_placement:     preferred placements when need to evict buffer
  57  *
  58  * Structure indicating the placement you request for an object.
  59  */
  60 struct ttm_placement {
  61         unsigned        fpfn;
  62         unsigned        lpfn;
  63         unsigned        num_placement;
  64         const uint32_t  *placement;
  65         unsigned        num_busy_placement;
  66         const uint32_t  *busy_placement;
  67 };
  68
  69 /**
  70  * struct ttm_bus_placement
  71  *
  72  * @addr:               mapped virtual address
  73  * @base:               bus base address
  74  * @is_iomem:           is this io memory ?
  75  * @size:               size in byte
  76  * @offset:             offset from the base address
  77  * @io_reserved_vm:     The VM system has a refcount in @io_reserved_count
  78  * @io_reserved_count:  Refcounting the numbers of callers to ttm_mem_io_reserve
  79  *
  80  * Structure indicating the bus placement of an object.
  81  */
  82 struct ttm_bus_placement {
  83         void            *addr;
  84         unsigned long   base;
  85         unsigned long   size;
  86         unsigned long   offset;
  87         bool            is_iomem;
  88         bool            io_reserved_vm;
  89         uint64_t        io_reserved_count;
  90 };
  91
  92
  93 /**
  94  * struct ttm_mem_reg
  95  *
  96  * @mm_node: Memory manager node.
  97  * @size: Requested size of memory region.
  98  * @num_pages: Actual size of memory region in pages.
  99  * @page_alignment: Page alignment.
 100  * @placement: Placement flags.
 101  * @bus: Placement on io bus accessible to the CPU
 102  *
 103  * Structure indicating the placement and space resources used by a
 104  * buffer object.
 105  */
 106
 107 struct ttm_mem_reg {
 108         void *mm_node;
 109         unsigned long start;
 110         unsigned long size;
 111         unsigned long num_pages;
 112         uint32_t page_alignment;
 113         uint32_t mem_type;
 114         uint32_t placement;
 115         struct ttm_bus_placement bus;
 116 };
 117
 118 /**
 119  * enum ttm_bo_type
 120  *
 121  * @ttm_bo_type_device: These are 'normal' buffers that can
 122  * be mmapped by user space. Each of these bos occupy a slot in the
 123  * device address space, that can be used for normal vm operations.
 124  *
 125  * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
 126  * but they cannot be accessed from user-space. For kernel-only use.
 127  *
 128  * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another
 129  * driver.
 130  */
 131
 132 enum ttm_bo_type {
 133         ttm_bo_type_device,
 134         ttm_bo_type_kernel,
 135         ttm_bo_type_sg
 136 };
 137
 138 struct ttm_tt;
 139
 140 /**
 141  * struct ttm_buffer_object
 142  *
 143  * @bdev: Pointer to the buffer object device structure.
 144  * @type: The bo type.
 145  * @destroy: Destruction function. If NULL, kfree is used.
 146  * @num_pages: Actual number of pages.
 147  * @addr_space_offset: Address space offset.
 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  * @event_queue: Queue for processes waiting on buffer object status change.
 157  * @mem: structure describing current placement.
 158  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 159  * pinned in physical memory. If this behaviour is not desired, this member
 160  * holds a pointer to a persistent shmem object.
 161  * @ttm: TTM structure holding system pages.
 162  * @evicted: Whether the object was evicted without user-space knowing.
 163  * @cpu_writes: For synchronization. Number of cpu writers.
 164  * @lru: List head for the lru list.
 165  * @ddestroy: List head for the delayed destroy list.
 166  * @swap: List head for swap LRU list.
 167  * @val_seq: Sequence of the validation holding the @reserved lock.
 168  * Used to avoid starvation when many processes compete to validate the
 169  * buffer. This member is protected by the bo_device::lru_lock.
 170  * @seq_valid: The value of @val_seq is valid. This value is protected by
 171  * the bo_device::lru_lock.
 172  * @reserved: Deadlock-free lock used for synchronization state transitions.
 173  * @sync_obj_arg: Opaque argument to synchronization object function.
 174  * @sync_obj: Pointer to a synchronization object.
 175  * @priv_flags: Flags describing buffer object internal state.
 176  * @vm_rb: Rb node for the vm rb tree.
 177  * @vm_node: Address space manager node.
 178  * @offset: The current GPU offset, which can have different meanings
 179  * depending on the memory type. For SYSTEM type memory, it should be 0.
 180  * @cur_placement: Hint of current placement.
 181  *
 182  * Base class for TTM buffer object, that deals with data placement and CPU
 183  * mappings. GPU mappings are really up to the driver, but for simpler GPUs
 184  * the driver can usually use the placement offset @offset directly as the
 185  * GPU virtual address. For drivers implementing multiple
 186  * GPU memory manager contexts, the driver should manage the address space
 187  * in these contexts separately and use these objects to get the correct
 188  * placement and caching for these GPU maps. This makes it possible to use
 189  * these objects for even quite elaborate memory management schemes.
 190  * The destroy member, the API visibility of this object makes it possible
 191  * to derive driver specific types.
 192  */
 193
 194 struct ttm_buffer_object {
 195         /**
 196          * Members constant at init.
 197          */
 198
 199         struct ttm_bo_global *glob;
 200         struct ttm_bo_device *bdev;
 201         enum ttm_bo_type type;
 202         void (*destroy) (struct ttm_buffer_object *);
 203         unsigned long num_pages;
 204         uint64_t addr_space_offset;
 205         size_t acc_size;
 206
 207         /**
 208         * Members not needing protection.
 209         */
 210
 211         struct kref kref;
 212         struct kref list_kref;
 213         wait_queue_head_t event_queue;
 214
 215         /**
 216          * Members protected by the bo::reserved lock.
 217          */
 218
 219         struct ttm_mem_reg mem;
 220         struct file *persistent_swap_storage;
 221         struct ttm_tt *ttm;
 222         bool evicted;
 223
 224         /**
 225          * Members protected by the bo::reserved lock only when written to.
 226          */
 227
 228         atomic_t cpu_writers;
 229
 230         /**
 231          * Members protected by the bdev::lru_lock.
 232          */
 233
 234         struct list_head lru;
 235         struct list_head ddestroy;
 236         struct list_head swap;
 237         struct list_head io_reserve_lru;
 238         uint32_t val_seq;
 239         bool seq_valid;
 240
 241         /**
 242          * Members protected by the bdev::lru_lock
 243          * only when written to.
 244          */
 245
 246         atomic_t reserved;
 247
 248         /**
 249          * Members protected by struct buffer_object_device::fence_lock
 250          * In addition, setting sync_obj to anything else
 251          * than NULL requires bo::reserved to be held. This allows for
 252          * checking NULL while reserved but not holding the mentioned lock.
 253          */
 254
 255         void *sync_obj_arg;
 256         void *sync_obj;
 257         unsigned long priv_flags;
 258
 259         /**
 260          * Members protected by the bdev::vm_lock
 261          */
 262
 263         struct rb_node vm_rb;
 264         struct drm_mm_node *vm_node;
 265
 266
 267         /**
 268          * Special members that are protected by the reserve lock
 269          * and the bo::lock when written to. Can be read with
 270          * either of these locks held.
 271          */
 272
 273         unsigned long offset;
 274         uint32_t cur_placement;
 275
 276         struct sg_table *sg;
 277 };
 278
 279 /**
 280  * struct ttm_bo_kmap_obj
 281  *
 282  * @virtual: The current kernel virtual address.
 283  * @page: The page when kmap'ing a single page.
 284  * @bo_kmap_type: Type of bo_kmap.
 285  *
 286  * Object describing a kernel mapping. Since a TTM bo may be located
 287  * in various memory types with various caching policies, the
 288  * mapping can either be an ioremap, a vmap, a kmap or part of a
 289  * premapped region.
 290  */
 291
 292 #define TTM_BO_MAP_IOMEM_MASK 0x80
 293 struct ttm_bo_kmap_obj {
 294         void *virtual;
 295         struct page *page;
 296         enum {
 297                 ttm_bo_map_iomap        = 1 | TTM_BO_MAP_IOMEM_MASK,
 298                 ttm_bo_map_vmap         = 2,
 299                 ttm_bo_map_kmap         = 3,
 300                 ttm_bo_map_premapped    = 4 | TTM_BO_MAP_IOMEM_MASK,
 301         } bo_kmap_type;
 302         struct ttm_buffer_object *bo;
 303 };
 304
 305 /**
 306  * ttm_bo_reference - reference a struct ttm_buffer_object
 307  *
 308  * @bo: The buffer object.
 309  *
 310  * Returns a refcounted pointer to a buffer object.
 311  */
 312
 313 static inline struct ttm_buffer_object *
 314 ttm_bo_reference(struct ttm_buffer_object *bo)
 315 {
 316         kref_get(&bo->kref);
 317         return bo;
 318 }
 319
 320 /**
 321  * ttm_bo_wait - wait for buffer idle.
 322  *
 323  * @bo:  The buffer object.
 324  * @interruptible:  Use interruptible wait.
 325  * @no_wait:  Return immediately if buffer is busy.
 326  *
 327  * This function must be called with the bo::mutex held, and makes
 328  * sure any previous rendering to the buffer is completed.
 329  * Note: It might be necessary to block validations before the
 330  * wait by reserving the buffer.
 331  * Returns -EBUSY if no_wait is true and the buffer is busy.
 332  * Returns -ERESTARTSYS if interrupted by a signal.
 333  */
 334 extern int ttm_bo_wait(struct ttm_buffer_object *bo, bool lazy,
 335                        bool interruptible, bool no_wait);
 336 /**
 337  * ttm_bo_validate
 338  *
 339  * @bo: The buffer object.
 340  * @placement: Proposed placement for the buffer object.
 341  * @interruptible: Sleep interruptible if sleeping.
 342  * @no_wait_reserve: Return immediately if other buffers are busy.
 343  * @no_wait_gpu: Return immediately if the GPU is busy.
 344  *
 345  * Changes placement and caching policy of the buffer object
 346  * according proposed placement.
 347  * Returns
 348  * -EINVAL on invalid proposed placement.
 349  * -ENOMEM on out-of-memory condition.
 350  * -EBUSY if no_wait is true and buffer busy.
 351  * -ERESTARTSYS if interrupted by a signal.
 352  */
 353 extern int ttm_bo_validate(struct ttm_buffer_object *bo,
 354                                 struct ttm_placement *placement,
 355                                 bool interruptible, bool no_wait_reserve,
 356                                 bool no_wait_gpu);
 357
 358 /**
 359  * ttm_bo_unref
 360  *
 361  * @bo: The buffer object.
 362  *
 363  * Unreference and clear a pointer to a buffer object.
 364  */
 365 extern void ttm_bo_unref(struct ttm_buffer_object **bo);
 366
 367
 368 /**
 369  * ttm_bo_list_ref_sub
 370  *
 371  * @bo: The buffer object.
 372  * @count: The number of references with which to decrease @bo::list_kref;
 373  * @never_free: The refcount should not reach zero with this operation.
 374  *
 375  * Release @count lru list references to this buffer object.
 376  */
 377 extern void ttm_bo_list_ref_sub(struct ttm_buffer_object *bo, int count,
 378                                 bool never_free);
 379
 380 /**
 381  * ttm_bo_add_to_lru
 382  *
 383  * @bo: The buffer object.
 384  *
 385  * Add this bo to the relevant mem type lru and, if it's backed by
 386  * system pages (ttms) to the swap list.
 387  * This function must be called with struct ttm_bo_global::lru_lock held, and
 388  * is typically called immediately prior to unreserving a bo.
 389  */
 390 extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
 391
 392 /**
 393  * ttm_bo_del_from_lru
 394  *
 395  * @bo: The buffer object.
 396  *
 397  * Remove this bo from all lru lists used to lookup and reserve an object.
 398  * This function must be called with struct ttm_bo_global::lru_lock held,
 399  * and is usually called just immediately after the bo has been reserved to
 400  * avoid recursive reservation from lru lists.
 401  */
 402 extern int ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
 403
 404
 405 /**
 406  * ttm_bo_lock_delayed_workqueue
 407  *
 408  * Prevent the delayed workqueue from running.
 409  * Returns
 410  * True if the workqueue was queued at the time
 411  */
 412 extern int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
 413
 414 /**
 415  * ttm_bo_unlock_delayed_workqueue
 416  *
 417  * Allows the delayed workqueue to run.
 418  */
 419 extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
 420                                             int resched);
 421
 422 /**
 423  * ttm_bo_synccpu_write_grab
 424  *
 425  * @bo: The buffer object:
 426  * @no_wait: Return immediately if buffer is busy.
 427  *
 428  * Synchronizes a buffer object for CPU RW access. This means
 429  * blocking command submission that affects the buffer and
 430  * waiting for buffer idle. This lock is recursive.
 431  * Returns
 432  * -EBUSY if the buffer is busy and no_wait is true.
 433  * -ERESTARTSYS if interrupted by a signal.
 434  */
 435 extern int
 436 ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
 437
 438 /**
 439  * ttm_bo_synccpu_write_release:
 440  *
 441  * @bo : The buffer object.
 442  *
 443  * Releases a synccpu lock.
 444  */
 445 extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
 446
 447 /**
 448  * ttm_bo_acc_size
 449  *
 450  * @bdev: Pointer to a ttm_bo_device struct.
 451  * @bo_size: size of the buffer object in byte.
 452  * @struct_size: size of the structure holding buffer object datas
 453  *
 454  * Returns size to account for a buffer object
 455  */
 456 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
 457                        unsigned long bo_size,
 458                        unsigned struct_size);
 459 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
 460                            unsigned long bo_size,
 461                            unsigned struct_size);
 462
 463 /**
 464  * ttm_bo_init
 465  *
 466  * @bdev: Pointer to a ttm_bo_device struct.
 467  * @bo: Pointer to a ttm_buffer_object to be initialized.
 468  * @size: Requested size of buffer object.
 469  * @type: Requested type of buffer object.
 470  * @flags: Initial placement flags.
 471  * @page_alignment: Data alignment in pages.
 472  * @interruptible: If needing to sleep to wait for GPU resources,
 473  * sleep interruptible.
 474  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 475  * pinned in physical memory. If this behaviour is not desired, this member
 476  * holds a pointer to a persistent shmem object. Typically, this would
 477  * point to the shmem object backing a GEM object if TTM is used to back a
 478  * GEM user interface.
 479  * @acc_size: Accounted size for this object.
 480  * @destroy: Destroy function. Use NULL for kfree().
 481  *
 482  * This function initializes a pre-allocated struct ttm_buffer_object.
 483  * As this object may be part of a larger structure, this function,
 484  * together with the @destroy function,
 485  * enables driver-specific objects derived from a ttm_buffer_object.
 486  * On successful return, the object kref and list_kref are set to 1.
 487  * If a failure occurs, the function will call the @destroy function, or
 488  * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
 489  * illegal and will likely cause memory corruption.
 490  *
 491  * Returns
 492  * -ENOMEM: Out of memory.
 493  * -EINVAL: Invalid placement flags.
 494  * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
 495  */
 496
 497 extern int ttm_bo_init(struct ttm_bo_device *bdev,
 498                         struct ttm_buffer_object *bo,
 499                         unsigned long size,
 500                         enum ttm_bo_type type,
 501                         struct ttm_placement *placement,
 502                         uint32_t page_alignment,
 503                         bool interrubtible,
 504                         struct file *persistent_swap_storage,
 505                         size_t acc_size,
 506                         struct sg_table *sg,
 507                         void (*destroy) (struct ttm_buffer_object *));
 508
 509 /**
 510  * ttm_bo_synccpu_object_init
 511  *
 512  * @bdev: Pointer to a ttm_bo_device struct.
 513  * @bo: Pointer to a ttm_buffer_object to be initialized.
 514  * @size: Requested size of buffer object.
 515  * @type: Requested type of buffer object.
 516  * @flags: Initial placement flags.
 517  * @page_alignment: Data alignment in pages.
 518  * @interruptible: If needing to sleep while waiting for GPU resources,
 519  * sleep interruptible.
 520  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
 521  * pinned in physical memory. If this behaviour is not desired, this member
 522  * holds a pointer to a persistent shmem object. Typically, this would
 523  * point to the shmem object backing a GEM object if TTM is used to back a
 524  * GEM user interface.
 525  * @p_bo: On successful completion *p_bo points to the created object.
 526  *
 527  * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
 528  * on that object. The destroy function is set to kfree().
 529  * Returns
 530  * -ENOMEM: Out of memory.
 531  * -EINVAL: Invalid placement flags.
 532  * -ERESTARTSYS: Interrupted by signal while waiting for resources.
 533  */
 534
 535 extern int ttm_bo_create(struct ttm_bo_device *bdev,
 536                                 unsigned long size,
 537                                 enum ttm_bo_type type,
 538                                 struct ttm_placement *placement,
 539                                 uint32_t page_alignment,
 540                                 bool interruptible,
 541                                 struct file *persistent_swap_storage,
 542                                 struct ttm_buffer_object **p_bo);
 543
 544 /**
 545  * ttm_bo_check_placement
 546  *
 547  * @bo:         the buffer object.
 548  * @placement:  placements
 549  *
 550  * Performs minimal validity checking on an intended change of
 551  * placement flags.
 552  * Returns
 553  * -EINVAL: Intended change is invalid or not allowed.
 554  */
 555 extern int ttm_bo_check_placement(struct ttm_buffer_object *bo,
 556                                         struct ttm_placement *placement);
 557
 558 /**
 559  * ttm_bo_init_mm
 560  *
 561  * @bdev: Pointer to a ttm_bo_device struct.
 562  * @mem_type: The memory type.
 563  * @p_size: size managed area in pages.
 564  *
 565  * Initialize a manager for a given memory type.
 566  * Note: if part of driver firstopen, it must be protected from a
 567  * potentially racing lastclose.
 568  * Returns:
 569  * -EINVAL: invalid size or memory type.
 570  * -ENOMEM: Not enough memory.
 571  * May also return driver-specified errors.
 572  */
 573
 574 extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
 575                                 unsigned long p_size);
 576 /**
 577  * ttm_bo_clean_mm
 578  *
 579  * @bdev: Pointer to a ttm_bo_device struct.
 580  * @mem_type: The memory type.
 581  *
 582  * Take down a manager for a given memory type after first walking
 583  * the LRU list to evict any buffers left alive.
 584  *
 585  * Normally, this function is part of lastclose() or unload(), and at that
 586  * point there shouldn't be any buffers left created by user-space, since
 587  * there should've been removed by the file descriptor release() method.
 588  * However, before this function is run, make sure to signal all sync objects,
 589  * and verify that the delayed delete queue is empty. The driver must also
 590  * make sure that there are no NO_EVICT buffers present in this memory type
 591  * when the call is made.
 592  *
 593  * If this function is part of a VT switch, the caller must make sure that
 594  * there are no appications currently validating buffers before this
 595  * function is called. The caller can do that by first taking the
 596  * struct ttm_bo_device::ttm_lock in write mode.
 597  *
 598  * Returns:
 599  * -EINVAL: invalid or uninitialized memory type.
 600  * -EBUSY: There are still buffers left in this memory type.
 601  */
 602
 603 extern int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
 604
 605 /**
 606  * ttm_bo_evict_mm
 607  *
 608  * @bdev: Pointer to a ttm_bo_device struct.
 609  * @mem_type: The memory type.
 610  *
 611  * Evicts all buffers on the lru list of the memory type.
 612  * This is normally part of a VT switch or an
 613  * out-of-memory-space-due-to-fragmentation handler.
 614  * The caller must make sure that there are no other processes
 615  * currently validating buffers, and can do that by taking the
 616  * struct ttm_bo_device::ttm_lock in write mode.
 617  *
 618  * Returns:
 619  * -EINVAL: Invalid or uninitialized memory type.
 620  * -ERESTARTSYS: The call was interrupted by a signal while waiting to
 621  * evict a buffer.
 622  */
 623
 624 extern int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
 625
 626 /**
 627  * ttm_kmap_obj_virtual
 628  *
 629  * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
 630  * @is_iomem: Pointer to an integer that on return indicates 1 if the
 631  * virtual map is io memory, 0 if normal memory.
 632  *
 633  * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
 634  * If *is_iomem is 1 on return, the virtual address points to an io memory area,
 635  * that should strictly be accessed by the iowriteXX() and similar functions.
 636  */
 637
 638 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
 639                                          bool *is_iomem)
 640 {
 641         *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
 642         return map->virtual;
 643 }
 644
 645 /**
 646  * ttm_bo_kmap
 647  *
 648  * @bo: The buffer object.
 649  * @start_page: The first page to map.
 650  * @num_pages: Number of pages to map.
 651  * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
 652  *
 653  * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
 654  * data in the buffer object. The ttm_kmap_obj_virtual function can then be
 655  * used to obtain a virtual address to the data.
 656  *
 657  * Returns
 658  * -ENOMEM: Out of memory.
 659  * -EINVAL: Invalid range.
 660  */
 661
 662 extern int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
 663                        unsigned long num_pages, struct ttm_bo_kmap_obj *map);
 664
 665 /**
 666  * ttm_bo_kunmap
 667  *
 668  * @map: Object describing the map to unmap.
 669  *
 670  * Unmaps a kernel map set up by ttm_bo_kmap.
 671  */
 672
 673 extern void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
 674
 675 /**
 676  * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
 677  *
 678  * @vma:       vma as input from the fbdev mmap method.
 679  * @bo:        The bo backing the address space. The address space will
 680  * have the same size as the bo, and start at offset 0.
 681  *
 682  * This function is intended to be called by the fbdev mmap method
 683  * if the fbdev address space is to be backed by a bo.
 684  */
 685
 686 extern int ttm_fbdev_mmap(struct vm_area_struct *vma,
 687                           struct ttm_buffer_object *bo);
 688
 689 /**
 690  * ttm_bo_mmap - mmap out of the ttm device address space.
 691  *
 692  * @filp:      filp as input from the mmap method.
 693  * @vma:       vma as input from the mmap method.
 694  * @bdev:      Pointer to the ttm_bo_device with the address space manager.
 695  *
 696  * This function is intended to be called by the device mmap method.
 697  * if the device address space is to be backed by the bo manager.
 698  */
 699
 700 extern int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 701                        struct ttm_bo_device *bdev);
 702
 703 /**
 704  * ttm_bo_io
 705  *
 706  * @bdev:      Pointer to the struct ttm_bo_device.
 707  * @filp:      Pointer to the struct file attempting to read / write.
 708  * @wbuf:      User-space pointer to address of buffer to write. NULL on read.
 709  * @rbuf:      User-space pointer to address of buffer to read into.
 710  * Null on write.
 711  * @count:     Number of bytes to read / write.
 712  * @f_pos:     Pointer to current file position.
 713  * @write:     1 for read, 0 for write.
 714  *
 715  * This function implements read / write into ttm buffer objects, and is
 716  * intended to
 717  * be called from the fops::read and fops::write method.
 718  * Returns:
 719  * See man (2) write, man(2) read. In particular,
 720  * the function may return -ERESTARTSYS if
 721  * interrupted by a signal.
 722  */
 723
 724 extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
 725                          const char __user *wbuf, char __user *rbuf,
 726                          size_t count, loff_t *f_pos, bool write);
 727
 728 extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
 729
 730 /**
 731  * ttm_bo_is_reserved - return an indication if a ttm buffer object is reserved
 732  *
 733  * @bo:     The buffer object to check.
 734  *
 735  * This function returns an indication if a bo is reserved or not, and should
 736  * only be used to print an error when it is not from incorrect api usage, since
 737  * there's no guarantee that it is the caller that is holding the reservation.
 738  */
 739 static inline bool ttm_bo_is_reserved(struct ttm_buffer_object *bo)
 740 {
 741         return atomic_read(&bo->reserved);
 742 }
 743
 744 #endif