1 /**************************************************************************
2  *
3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
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.
17  *
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,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
25  *
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_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 
129 enum ttm_bo_type {
130 	ttm_bo_type_device,
131 	ttm_bo_type_kernel
132 };
133 
134 struct ttm_tt;
135 
136 /**
137  * struct ttm_buffer_object
138  *
139  * @bdev: Pointer to the buffer object device structure.
140  * @buffer_start: The virtual user-space start address of ttm_bo_type_user
141  * buffers.
142  * @type: The bo type.
143  * @destroy: Destruction function. If NULL, kfree is used.
144  * @num_pages: Actual number of pages.
145  * @addr_space_offset: Address space offset.
146  * @acc_size: Accounted size for this object.
147  * @kref: Reference count of this buffer object. When this refcount reaches
148  * zero, the object is put on the delayed delete list.
149  * @list_kref: List reference count of this buffer object. This member is
150  * used to avoid destruction while the buffer object is still on a list.
151  * Lru lists may keep one refcount, the delayed delete list, and kref != 0
152  * keeps one refcount. When this refcount reaches zero,
153  * the object is destroyed.
154  * @event_queue: Queue for processes waiting on buffer object status change.
155  * @mem: structure describing current placement.
156  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
157  * pinned in physical memory. If this behaviour is not desired, this member
158  * holds a pointer to a persistent shmem object.
159  * @ttm: TTM structure holding system pages.
160  * @evicted: Whether the object was evicted without user-space knowing.
161  * @cpu_writes: For synchronization. Number of cpu writers.
162  * @lru: List head for the lru list.
163  * @ddestroy: List head for the delayed destroy list.
164  * @swap: List head for swap LRU list.
165  * @val_seq: Sequence of the validation holding the @reserved lock.
166  * Used to avoid starvation when many processes compete to validate the
167  * buffer. This member is protected by the bo_device::lru_lock.
168  * @seq_valid: The value of @val_seq is valid. This value is protected by
169  * the bo_device::lru_lock.
170  * @reserved: Deadlock-free lock used for synchronization state transitions.
171  * @sync_obj_arg: Opaque argument to synchronization object function.
172  * @sync_obj: Pointer to a synchronization object.
173  * @priv_flags: Flags describing buffer object internal state.
174  * @vm_rb: Rb node for the vm rb tree.
175  * @vm_node: Address space manager node.
176  * @offset: The current GPU offset, which can have different meanings
177  * depending on the memory type. For SYSTEM type memory, it should be 0.
178  * @cur_placement: Hint of current placement.
179  *
180  * Base class for TTM buffer object, that deals with data placement and CPU
181  * mappings. GPU mappings are really up to the driver, but for simpler GPUs
182  * the driver can usually use the placement offset @offset directly as the
183  * GPU virtual address. For drivers implementing multiple
184  * GPU memory manager contexts, the driver should manage the address space
185  * in these contexts separately and use these objects to get the correct
186  * placement and caching for these GPU maps. This makes it possible to use
187  * these objects for even quite elaborate memory management schemes.
188  * The destroy member, the API visibility of this object makes it possible
189  * to derive driver specific types.
190  */
191 
192 struct ttm_buffer_object {
193 	/**
194 	 * Members constant at init.
195 	 */
196 
197 	struct ttm_bo_global *glob;
198 	struct ttm_bo_device *bdev;
199 	unsigned long buffer_start;
200 	enum ttm_bo_type type;
201 	void (*destroy) (struct ttm_buffer_object *);
202 	unsigned long num_pages;
203 	uint64_t addr_space_offset;
204 	size_t acc_size;
205 
206 	/**
207 	* Members not needing protection.
208 	*/
209 
210 	struct kref kref;
211 	struct kref list_kref;
212 	wait_queue_head_t event_queue;
213 
214 	/**
215 	 * Members protected by the bo::reserved lock.
216 	 */
217 
218 	struct ttm_mem_reg mem;
219 	struct file *persistent_swap_storage;
220 	struct ttm_tt *ttm;
221 	bool evicted;
222 
223 	/**
224 	 * Members protected by the bo::reserved lock only when written to.
225 	 */
226 
227 	atomic_t cpu_writers;
228 
229 	/**
230 	 * Members protected by the bdev::lru_lock.
231 	 */
232 
233 	struct list_head lru;
234 	struct list_head ddestroy;
235 	struct list_head swap;
236 	struct list_head io_reserve_lru;
237 	uint32_t val_seq;
238 	bool seq_valid;
239 
240 	/**
241 	 * Members protected by the bdev::lru_lock
242 	 * only when written to.
243 	 */
244 
245 	atomic_t reserved;
246 
247 	/**
248 	 * Members protected by struct buffer_object_device::fence_lock
249 	 * In addition, setting sync_obj to anything else
250 	 * than NULL requires bo::reserved to be held. This allows for
251 	 * checking NULL while reserved but not holding the mentioned lock.
252 	 */
253 
254 	void *sync_obj_arg;
255 	void *sync_obj;
256 	unsigned long priv_flags;
257 
258 	/**
259 	 * Members protected by the bdev::vm_lock
260 	 */
261 
262 	struct rb_node vm_rb;
263 	struct drm_mm_node *vm_node;
264 
265 
266 	/**
267 	 * Special members that are protected by the reserve lock
268 	 * and the bo::lock when written to. Can be read with
269 	 * either of these locks held.
270 	 */
271 
272 	unsigned long offset;
273 	uint32_t cur_placement;
274 };
275 
276 /**
277  * struct ttm_bo_kmap_obj
278  *
279  * @virtual: The current kernel virtual address.
280  * @page: The page when kmap'ing a single page.
281  * @bo_kmap_type: Type of bo_kmap.
282  *
283  * Object describing a kernel mapping. Since a TTM bo may be located
284  * in various memory types with various caching policies, the
285  * mapping can either be an ioremap, a vmap, a kmap or part of a
286  * premapped region.
287  */
288 
289 #define TTM_BO_MAP_IOMEM_MASK 0x80
290 struct ttm_bo_kmap_obj {
291 	void *virtual;
292 	struct page *page;
293 	enum {
294 		ttm_bo_map_iomap        = 1 | TTM_BO_MAP_IOMEM_MASK,
295 		ttm_bo_map_vmap         = 2,
296 		ttm_bo_map_kmap         = 3,
297 		ttm_bo_map_premapped    = 4 | TTM_BO_MAP_IOMEM_MASK,
298 	} bo_kmap_type;
299 	struct ttm_buffer_object *bo;
300 };
301 
302 /**
303  * ttm_bo_reference - reference a struct ttm_buffer_object
304  *
305  * @bo: The buffer object.
306  *
307  * Returns a refcounted pointer to a buffer object.
308  */
309 
310 static inline struct ttm_buffer_object *
ttm_bo_reference(struct ttm_buffer_object * bo)311 ttm_bo_reference(struct ttm_buffer_object *bo)
312 {
313 	kref_get(&bo->kref);
314 	return bo;
315 }
316 
317 /**
318  * ttm_bo_wait - wait for buffer idle.
319  *
320  * @bo:  The buffer object.
321  * @interruptible:  Use interruptible wait.
322  * @no_wait:  Return immediately if buffer is busy.
323  *
324  * This function must be called with the bo::mutex held, and makes
325  * sure any previous rendering to the buffer is completed.
326  * Note: It might be necessary to block validations before the
327  * wait by reserving the buffer.
328  * Returns -EBUSY if no_wait is true and the buffer is busy.
329  * Returns -ERESTARTSYS if interrupted by a signal.
330  */
331 extern int ttm_bo_wait(struct ttm_buffer_object *bo, bool lazy,
332 		       bool interruptible, bool no_wait);
333 /**
334  * ttm_bo_validate
335  *
336  * @bo: The buffer object.
337  * @placement: Proposed placement for the buffer object.
338  * @interruptible: Sleep interruptible if sleeping.
339  * @no_wait_reserve: Return immediately if other buffers are busy.
340  * @no_wait_gpu: Return immediately if the GPU is busy.
341  *
342  * Changes placement and caching policy of the buffer object
343  * according proposed placement.
344  * Returns
345  * -EINVAL on invalid proposed placement.
346  * -ENOMEM on out-of-memory condition.
347  * -EBUSY if no_wait is true and buffer busy.
348  * -ERESTARTSYS if interrupted by a signal.
349  */
350 extern int ttm_bo_validate(struct ttm_buffer_object *bo,
351 				struct ttm_placement *placement,
352 				bool interruptible, bool no_wait_reserve,
353 				bool no_wait_gpu);
354 
355 /**
356  * ttm_bo_unref
357  *
358  * @bo: The buffer object.
359  *
360  * Unreference and clear a pointer to a buffer object.
361  */
362 extern void ttm_bo_unref(struct ttm_buffer_object **bo);
363 
364 
365 /**
366  * ttm_bo_list_ref_sub
367  *
368  * @bo: The buffer object.
369  * @count: The number of references with which to decrease @bo::list_kref;
370  * @never_free: The refcount should not reach zero with this operation.
371  *
372  * Release @count lru list references to this buffer object.
373  */
374 extern void ttm_bo_list_ref_sub(struct ttm_buffer_object *bo, int count,
375 				bool never_free);
376 
377 /**
378  * ttm_bo_add_to_lru
379  *
380  * @bo: The buffer object.
381  *
382  * Add this bo to the relevant mem type lru and, if it's backed by
383  * system pages (ttms) to the swap list.
384  * This function must be called with struct ttm_bo_global::lru_lock held, and
385  * is typically called immediately prior to unreserving a bo.
386  */
387 extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
388 
389 /**
390  * ttm_bo_del_from_lru
391  *
392  * @bo: The buffer object.
393  *
394  * Remove this bo from all lru lists used to lookup and reserve an object.
395  * This function must be called with struct ttm_bo_global::lru_lock held,
396  * and is usually called just immediately after the bo has been reserved to
397  * avoid recursive reservation from lru lists.
398  */
399 extern int ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
400 
401 
402 /**
403  * ttm_bo_lock_delayed_workqueue
404  *
405  * Prevent the delayed workqueue from running.
406  * Returns
407  * True if the workqueue was queued at the time
408  */
409 extern int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
410 
411 /**
412  * ttm_bo_unlock_delayed_workqueue
413  *
414  * Allows the delayed workqueue to run.
415  */
416 extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
417 					    int resched);
418 
419 /**
420  * ttm_bo_synccpu_write_grab
421  *
422  * @bo: The buffer object:
423  * @no_wait: Return immediately if buffer is busy.
424  *
425  * Synchronizes a buffer object for CPU RW access. This means
426  * blocking command submission that affects the buffer and
427  * waiting for buffer idle. This lock is recursive.
428  * Returns
429  * -EBUSY if the buffer is busy and no_wait is true.
430  * -ERESTARTSYS if interrupted by a signal.
431  */
432 extern int
433 ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
434 
435 /**
436  * ttm_bo_synccpu_write_release:
437  *
438  * @bo : The buffer object.
439  *
440  * Releases a synccpu lock.
441  */
442 extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
443 
444 /**
445  * ttm_bo_acc_size
446  *
447  * @bdev: Pointer to a ttm_bo_device struct.
448  * @bo_size: size of the buffer object in byte.
449  * @struct_size: size of the structure holding buffer object datas
450  *
451  * Returns size to account for a buffer object
452  */
453 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
454 		       unsigned long bo_size,
455 		       unsigned struct_size);
456 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
457 			   unsigned long bo_size,
458 			   unsigned struct_size);
459 
460 /**
461  * ttm_bo_init
462  *
463  * @bdev: Pointer to a ttm_bo_device struct.
464  * @bo: Pointer to a ttm_buffer_object to be initialized.
465  * @size: Requested size of buffer object.
466  * @type: Requested type of buffer object.
467  * @flags: Initial placement flags.
468  * @page_alignment: Data alignment in pages.
469  * @buffer_start: Virtual address of user space data backing a
470  * user buffer object.
471  * @interruptible: If needing to sleep to wait for GPU resources,
472  * sleep interruptible.
473  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
474  * pinned in physical memory. If this behaviour is not desired, this member
475  * holds a pointer to a persistent shmem object. Typically, this would
476  * point to the shmem object backing a GEM object if TTM is used to back a
477  * GEM user interface.
478  * @acc_size: Accounted size for this object.
479  * @destroy: Destroy function. Use NULL for kfree().
480  *
481  * This function initializes a pre-allocated struct ttm_buffer_object.
482  * As this object may be part of a larger structure, this function,
483  * together with the @destroy function,
484  * enables driver-specific objects derived from a ttm_buffer_object.
485  * On successful return, the object kref and list_kref are set to 1.
486  * If a failure occurs, the function will call the @destroy function, or
487  * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
488  * illegal and will likely cause memory corruption.
489  *
490  * Returns
491  * -ENOMEM: Out of memory.
492  * -EINVAL: Invalid placement flags.
493  * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
494  */
495 
496 extern int ttm_bo_init(struct ttm_bo_device *bdev,
497 			struct ttm_buffer_object *bo,
498 			unsigned long size,
499 			enum ttm_bo_type type,
500 			struct ttm_placement *placement,
501 			uint32_t page_alignment,
502 			unsigned long buffer_start,
503 			bool interrubtible,
504 			struct file *persistent_swap_storage,
505 			size_t acc_size,
506 			void (*destroy) (struct ttm_buffer_object *));
507 
508 /**
509  * ttm_bo_synccpu_object_init
510  *
511  * @bdev: Pointer to a ttm_bo_device struct.
512  * @bo: Pointer to a ttm_buffer_object to be initialized.
513  * @size: Requested size of buffer object.
514  * @type: Requested type of buffer object.
515  * @flags: Initial placement flags.
516  * @page_alignment: Data alignment in pages.
517  * @buffer_start: Virtual address of user space data backing a
518  * user buffer object.
519  * @interruptible: If needing to sleep while waiting for GPU resources,
520  * sleep interruptible.
521  * @persistent_swap_storage: Usually the swap storage is deleted for buffers
522  * pinned in physical memory. If this behaviour is not desired, this member
523  * holds a pointer to a persistent shmem object. Typically, this would
524  * point to the shmem object backing a GEM object if TTM is used to back a
525  * GEM user interface.
526  * @p_bo: On successful completion *p_bo points to the created object.
527  *
528  * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
529  * on that object. The destroy function is set to kfree().
530  * Returns
531  * -ENOMEM: Out of memory.
532  * -EINVAL: Invalid placement flags.
533  * -ERESTARTSYS: Interrupted by signal while waiting for resources.
534  */
535 
536 extern int ttm_bo_create(struct ttm_bo_device *bdev,
537 				unsigned long size,
538 				enum ttm_bo_type type,
539 				struct ttm_placement *placement,
540 				uint32_t page_alignment,
541 				unsigned long buffer_start,
542 				bool interruptible,
543 				struct file *persistent_swap_storage,
544 				struct ttm_buffer_object **p_bo);
545 
546 /**
547  * ttm_bo_check_placement
548  *
549  * @bo:		the buffer object.
550  * @placement:	placements
551  *
552  * Performs minimal validity checking on an intended change of
553  * placement flags.
554  * Returns
555  * -EINVAL: Intended change is invalid or not allowed.
556  */
557 extern int ttm_bo_check_placement(struct ttm_buffer_object *bo,
558 					struct ttm_placement *placement);
559 
560 /**
561  * ttm_bo_init_mm
562  *
563  * @bdev: Pointer to a ttm_bo_device struct.
564  * @mem_type: The memory type.
565  * @p_size: size managed area in pages.
566  *
567  * Initialize a manager for a given memory type.
568  * Note: if part of driver firstopen, it must be protected from a
569  * potentially racing lastclose.
570  * Returns:
571  * -EINVAL: invalid size or memory type.
572  * -ENOMEM: Not enough memory.
573  * May also return driver-specified errors.
574  */
575 
576 extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
577 				unsigned long p_size);
578 /**
579  * ttm_bo_clean_mm
580  *
581  * @bdev: Pointer to a ttm_bo_device struct.
582  * @mem_type: The memory type.
583  *
584  * Take down a manager for a given memory type after first walking
585  * the LRU list to evict any buffers left alive.
586  *
587  * Normally, this function is part of lastclose() or unload(), and at that
588  * point there shouldn't be any buffers left created by user-space, since
589  * there should've been removed by the file descriptor release() method.
590  * However, before this function is run, make sure to signal all sync objects,
591  * and verify that the delayed delete queue is empty. The driver must also
592  * make sure that there are no NO_EVICT buffers present in this memory type
593  * when the call is made.
594  *
595  * If this function is part of a VT switch, the caller must make sure that
596  * there are no appications currently validating buffers before this
597  * function is called. The caller can do that by first taking the
598  * struct ttm_bo_device::ttm_lock in write mode.
599  *
600  * Returns:
601  * -EINVAL: invalid or uninitialized memory type.
602  * -EBUSY: There are still buffers left in this memory type.
603  */
604 
605 extern int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
606 
607 /**
608  * ttm_bo_evict_mm
609  *
610  * @bdev: Pointer to a ttm_bo_device struct.
611  * @mem_type: The memory type.
612  *
613  * Evicts all buffers on the lru list of the memory type.
614  * This is normally part of a VT switch or an
615  * out-of-memory-space-due-to-fragmentation handler.
616  * The caller must make sure that there are no other processes
617  * currently validating buffers, and can do that by taking the
618  * struct ttm_bo_device::ttm_lock in write mode.
619  *
620  * Returns:
621  * -EINVAL: Invalid or uninitialized memory type.
622  * -ERESTARTSYS: The call was interrupted by a signal while waiting to
623  * evict a buffer.
624  */
625 
626 extern int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
627 
628 /**
629  * ttm_kmap_obj_virtual
630  *
631  * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
632  * @is_iomem: Pointer to an integer that on return indicates 1 if the
633  * virtual map is io memory, 0 if normal memory.
634  *
635  * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
636  * If *is_iomem is 1 on return, the virtual address points to an io memory area,
637  * that should strictly be accessed by the iowriteXX() and similar functions.
638  */
639 
ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj * map,bool * is_iomem)640 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
641 					 bool *is_iomem)
642 {
643 	*is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
644 	return map->virtual;
645 }
646 
647 /**
648  * ttm_bo_kmap
649  *
650  * @bo: The buffer object.
651  * @start_page: The first page to map.
652  * @num_pages: Number of pages to map.
653  * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
654  *
655  * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
656  * data in the buffer object. The ttm_kmap_obj_virtual function can then be
657  * used to obtain a virtual address to the data.
658  *
659  * Returns
660  * -ENOMEM: Out of memory.
661  * -EINVAL: Invalid range.
662  */
663 
664 extern int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
665 		       unsigned long num_pages, struct ttm_bo_kmap_obj *map);
666 
667 /**
668  * ttm_bo_kunmap
669  *
670  * @map: Object describing the map to unmap.
671  *
672  * Unmaps a kernel map set up by ttm_bo_kmap.
673  */
674 
675 extern void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
676 
677 /**
678  * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
679  *
680  * @vma:       vma as input from the fbdev mmap method.
681  * @bo:        The bo backing the address space. The address space will
682  * have the same size as the bo, and start at offset 0.
683  *
684  * This function is intended to be called by the fbdev mmap method
685  * if the fbdev address space is to be backed by a bo.
686  */
687 
688 extern int ttm_fbdev_mmap(struct vm_area_struct *vma,
689 			  struct ttm_buffer_object *bo);
690 
691 /**
692  * ttm_bo_mmap - mmap out of the ttm device address space.
693  *
694  * @filp:      filp as input from the mmap method.
695  * @vma:       vma as input from the mmap method.
696  * @bdev:      Pointer to the ttm_bo_device with the address space manager.
697  *
698  * This function is intended to be called by the device mmap method.
699  * if the device address space is to be backed by the bo manager.
700  */
701 
702 extern int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
703 		       struct ttm_bo_device *bdev);
704 
705 /**
706  * ttm_bo_io
707  *
708  * @bdev:      Pointer to the struct ttm_bo_device.
709  * @filp:      Pointer to the struct file attempting to read / write.
710  * @wbuf:      User-space pointer to address of buffer to write. NULL on read.
711  * @rbuf:      User-space pointer to address of buffer to read into.
712  * Null on write.
713  * @count:     Number of bytes to read / write.
714  * @f_pos:     Pointer to current file position.
715  * @write:     1 for read, 0 for write.
716  *
717  * This function implements read / write into ttm buffer objects, and is
718  * intended to
719  * be called from the fops::read and fops::write method.
720  * Returns:
721  * See man (2) write, man(2) read. In particular,
722  * the function may return -ERESTARTSYS if
723  * interrupted by a signal.
724  */
725 
726 extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
727 			 const char __user *wbuf, char __user *rbuf,
728 			 size_t count, loff_t *f_pos, bool write);
729 
730 extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
731 
732 #endif
733