1 /**************************************************************************
3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
6 * Permission is hereby granted, free of charge, to any person obtaining a
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26 **************************************************************************/
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
32 #ifndef _TTM_BO_API_H_
33 #define _TTM_BO_API_H_
35 #include <dev/drm2/drmP.h>
43 * struct ttm_placement
45 * @fpfn: first valid page frame number to put the object
46 * @lpfn: last valid page frame number to put the object
47 * @num_placement: number of preferred placements
48 * @placement: preferred placements
49 * @num_busy_placement: number of preferred placements when need to evict buffer
50 * @busy_placement: preferred placements when need to evict buffer
52 * Structure indicating the placement you request for an object.
54 struct ttm_placement {
57 unsigned num_placement;
58 const uint32_t *placement;
59 unsigned num_busy_placement;
60 const uint32_t *busy_placement;
64 * struct ttm_bus_placement
66 * @addr: mapped virtual address
67 * @base: bus base address
68 * @is_iomem: is this io memory ?
70 * @offset: offset from the base address
71 * @io_reserved_vm: The VM system has a refcount in @io_reserved_count
72 * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve
74 * Structure indicating the bus placement of an object.
76 struct ttm_bus_placement {
83 uint64_t io_reserved_count;
90 * @mm_node: Memory manager node.
91 * @size: Requested size of memory region.
92 * @num_pages: Actual size of memory region in pages.
93 * @page_alignment: Page alignment.
94 * @placement: Placement flags.
95 * @bus: Placement on io bus accessible to the CPU
97 * Structure indicating the placement and space resources used by a
105 unsigned long num_pages;
106 uint32_t page_alignment;
109 struct ttm_bus_placement bus;
115 * @ttm_bo_type_device: These are 'normal' buffers that can
116 * be mmapped by user space. Each of these bos occupy a slot in the
117 * device address space, that can be used for normal vm operations.
119 * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
120 * but they cannot be accessed from user-space. For kernel-only use.
122 * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another
135 * struct ttm_buffer_object
137 * @bdev: Pointer to the buffer object device structure.
138 * @type: The bo type.
139 * @destroy: Destruction function. If NULL, kfree is used.
140 * @num_pages: Actual number of pages.
141 * @addr_space_offset: Address space offset.
142 * @acc_size: Accounted size for this object.
143 * @kref: Reference count of this buffer object. When this refcount reaches
144 * zero, the object is put on the delayed delete list.
145 * @list_kref: List reference count of this buffer object. This member is
146 * used to avoid destruction while the buffer object is still on a list.
147 * Lru lists may keep one refcount, the delayed delete list, and kref != 0
148 * keeps one refcount. When this refcount reaches zero,
149 * the object is destroyed.
150 * @event_queue: Queue for processes waiting on buffer object status change.
151 * @mem: structure describing current placement.
152 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
153 * pinned in physical memory. If this behaviour is not desired, this member
154 * holds a pointer to a persistent shmem object.
155 * @ttm: TTM structure holding system pages.
156 * @evicted: Whether the object was evicted without user-space knowing.
157 * @cpu_writes: For synchronization. Number of cpu writers.
158 * @lru: List head for the lru list.
159 * @ddestroy: List head for the delayed destroy list.
160 * @swap: List head for swap LRU list.
161 * @val_seq: Sequence of the validation holding the @reserved lock.
162 * Used to avoid starvation when many processes compete to validate the
163 * buffer. This member is protected by the bo_device::lru_lock.
164 * @seq_valid: The value of @val_seq is valid. This value is protected by
165 * the bo_device::lru_lock.
166 * @reserved: Deadlock-free lock used for synchronization state transitions.
167 * @sync_obj: Pointer to a synchronization object.
168 * @priv_flags: Flags describing buffer object internal state.
169 * @vm_rb: Rb node for the vm rb tree.
170 * @vm_node: Address space manager node.
171 * @offset: The current GPU offset, which can have different meanings
172 * depending on the memory type. For SYSTEM type memory, it should be 0.
173 * @cur_placement: Hint of current placement.
175 * Base class for TTM buffer object, that deals with data placement and CPU
176 * mappings. GPU mappings are really up to the driver, but for simpler GPUs
177 * the driver can usually use the placement offset @offset directly as the
178 * GPU virtual address. For drivers implementing multiple
179 * GPU memory manager contexts, the driver should manage the address space
180 * in these contexts separately and use these objects to get the correct
181 * placement and caching for these GPU maps. This makes it possible to use
182 * these objects for even quite elaborate memory management schemes.
183 * The destroy member, the API visibility of this object makes it possible
184 * to derive driver specific types.
187 struct ttm_buffer_object {
189 * Members constant at init.
192 struct ttm_bo_global *glob;
193 struct ttm_bo_device *bdev;
194 enum ttm_bo_type type;
195 void (*destroy) (struct ttm_buffer_object *);
196 unsigned long num_pages;
197 uint64_t addr_space_offset;
201 * Members not needing protection.
206 /* wait_queue_head_t event_queue; */
209 * Members protected by the bo::reserved lock.
212 struct ttm_mem_reg mem;
213 struct vm_object *persistent_swap_storage;
218 * Members protected by the bo::reserved lock only when written to.
221 atomic_t cpu_writers;
224 * Members protected by the bdev::lru_lock.
227 struct list_head lru;
228 struct list_head ddestroy;
229 struct list_head swap;
230 struct list_head io_reserve_lru;
235 * Members protected by the bdev::lru_lock
236 * only when written to.
242 * Members protected by struct buffer_object_device::fence_lock
243 * In addition, setting sync_obj to anything else
244 * than NULL requires bo::reserved to be held. This allows for
245 * checking NULL while reserved but not holding the mentioned lock.
249 unsigned long priv_flags;
252 * Members protected by the bdev::vm_lock
255 RB_ENTRY(ttm_buffer_object) vm_rb;
256 struct drm_mm_node *vm_node;
260 * Special members that are protected by the reserve lock
261 * and the bo::lock when written to. Can be read with
262 * either of these locks held.
265 unsigned long offset;
266 uint32_t cur_placement;
272 * struct ttm_bo_kmap_obj
274 * @virtual: The current kernel virtual address.
275 * @page: The page when kmap'ing a single page.
276 * @bo_kmap_type: Type of bo_kmap.
278 * Object describing a kernel mapping. Since a TTM bo may be located
279 * in various memory types with various caching policies, the
280 * mapping can either be an ioremap, a vmap, a kmap or part of a
284 #define TTM_BO_MAP_IOMEM_MASK 0x80
285 struct ttm_bo_kmap_obj {
287 struct vm_page *page;
292 ttm_bo_map_iomap = 1 | TTM_BO_MAP_IOMEM_MASK,
295 ttm_bo_map_premapped = 4 | TTM_BO_MAP_IOMEM_MASK,
297 struct ttm_buffer_object *bo;
301 * ttm_bo_reference - reference a struct ttm_buffer_object
303 * @bo: The buffer object.
305 * Returns a refcounted pointer to a buffer object.
308 static inline struct ttm_buffer_object *
309 ttm_bo_reference(struct ttm_buffer_object *bo)
311 refcount_acquire(&bo->kref);
316 * ttm_bo_wait - wait for buffer idle.
318 * @bo: The buffer object.
319 * @interruptible: Use interruptible wait.
320 * @no_wait: Return immediately if buffer is busy.
322 * This function must be called with the bo::mutex held, and makes
323 * sure any previous rendering to the buffer is completed.
324 * Note: It might be necessary to block validations before the
325 * wait by reserving the buffer.
326 * Returns -EBUSY if no_wait is true and the buffer is busy.
327 * Returns -ERESTARTSYS if interrupted by a signal.
329 extern int ttm_bo_wait(struct ttm_buffer_object *bo, bool lazy,
330 bool interruptible, bool no_wait);
334 * @bo: The buffer object.
335 * @placement: Proposed placement for the buffer object.
336 * @interruptible: Sleep interruptible if sleeping.
337 * @no_wait_gpu: Return immediately if the GPU is busy.
339 * Changes placement and caching policy of the buffer object
340 * according proposed placement.
342 * -EINVAL on invalid proposed placement.
343 * -ENOMEM on out-of-memory condition.
344 * -EBUSY if no_wait is true and buffer busy.
345 * -ERESTARTSYS if interrupted by a signal.
347 extern int ttm_bo_validate(struct ttm_buffer_object *bo,
348 struct ttm_placement *placement,
355 * @bo: The buffer object.
357 * Unreference and clear a pointer to a buffer object.
359 extern void ttm_bo_unref(struct ttm_buffer_object **bo);
363 * ttm_bo_list_ref_sub
365 * @bo: The buffer object.
366 * @count: The number of references with which to decrease @bo::list_kref;
367 * @never_free: The refcount should not reach zero with this operation.
369 * Release @count lru list references to this buffer object.
371 extern void ttm_bo_list_ref_sub(struct ttm_buffer_object *bo, int count,
377 * @bo: The buffer object.
379 * Add this bo to the relevant mem type lru and, if it's backed by
380 * system pages (ttms) to the swap list.
381 * This function must be called with struct ttm_bo_global::lru_lock held, and
382 * is typically called immediately prior to unreserving a bo.
384 extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
387 * ttm_bo_del_from_lru
389 * @bo: The buffer object.
391 * Remove this bo from all lru lists used to lookup and reserve an object.
392 * This function must be called with struct ttm_bo_global::lru_lock held,
393 * and is usually called just immediately after the bo has been reserved to
394 * avoid recursive reservation from lru lists.
396 extern int ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
400 * ttm_bo_lock_delayed_workqueue
402 * Prevent the delayed workqueue from running.
404 * True if the workqueue was queued at the time
406 extern int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
409 * ttm_bo_unlock_delayed_workqueue
411 * Allows the delayed workqueue to run.
413 extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
417 * ttm_bo_synccpu_write_grab
419 * @bo: The buffer object:
420 * @no_wait: Return immediately if buffer is busy.
422 * Synchronizes a buffer object for CPU RW access. This means
423 * command submission that affects the buffer will return -EBUSY
424 * until ttm_bo_synccpu_write_release is called.
427 * -EBUSY if the buffer is busy and no_wait is true.
428 * -ERESTARTSYS if interrupted by a signal.
431 ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
434 * ttm_bo_synccpu_write_release:
436 * @bo : The buffer object.
438 * Releases a synccpu lock.
440 extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
445 * @bdev: Pointer to a ttm_bo_device struct.
446 * @bo_size: size of the buffer object in byte.
447 * @struct_size: size of the structure holding buffer object datas
449 * Returns size to account for a buffer object
451 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
452 unsigned long bo_size,
453 unsigned struct_size);
454 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
455 unsigned long bo_size,
456 unsigned struct_size);
461 * @bdev: Pointer to a ttm_bo_device struct.
462 * @bo: Pointer to a ttm_buffer_object to be initialized.
463 * @size: Requested size of buffer object.
464 * @type: Requested type of buffer object.
465 * @flags: Initial placement flags.
466 * @page_alignment: Data alignment in pages.
467 * @interruptible: If needing to sleep to wait for GPU resources,
468 * sleep interruptible.
469 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
470 * pinned in physical memory. If this behaviour is not desired, this member
471 * holds a pointer to a persistent shmem object. Typically, this would
472 * point to the shmem object backing a GEM object if TTM is used to back a
473 * GEM user interface.
474 * @acc_size: Accounted size for this object.
475 * @destroy: Destroy function. Use NULL for kfree().
477 * This function initializes a pre-allocated struct ttm_buffer_object.
478 * As this object may be part of a larger structure, this function,
479 * together with the @destroy function,
480 * enables driver-specific objects derived from a ttm_buffer_object.
481 * On successful return, the object kref and list_kref are set to 1.
482 * If a failure occurs, the function will call the @destroy function, or
483 * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
484 * illegal and will likely cause memory corruption.
487 * -ENOMEM: Out of memory.
488 * -EINVAL: Invalid placement flags.
489 * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
492 extern int ttm_bo_init(struct ttm_bo_device *bdev,
493 struct ttm_buffer_object *bo,
495 enum ttm_bo_type type,
496 struct ttm_placement *placement,
497 uint32_t page_alignment,
499 struct vm_object *persistent_swap_storage,
502 void (*destroy) (struct ttm_buffer_object *));
505 * ttm_bo_synccpu_object_init
507 * @bdev: Pointer to a ttm_bo_device struct.
508 * @bo: Pointer to a ttm_buffer_object to be initialized.
509 * @size: Requested size of buffer object.
510 * @type: Requested type of buffer object.
511 * @flags: Initial placement flags.
512 * @page_alignment: Data alignment in pages.
513 * @interruptible: If needing to sleep while waiting for GPU resources,
514 * sleep interruptible.
515 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
516 * pinned in physical memory. If this behaviour is not desired, this member
517 * holds a pointer to a persistent shmem object. Typically, this would
518 * point to the shmem object backing a GEM object if TTM is used to back a
519 * GEM user interface.
520 * @p_bo: On successful completion *p_bo points to the created object.
522 * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
523 * on that object. The destroy function is set to kfree().
525 * -ENOMEM: Out of memory.
526 * -EINVAL: Invalid placement flags.
527 * -ERESTARTSYS: Interrupted by signal while waiting for resources.
530 extern int ttm_bo_create(struct ttm_bo_device *bdev,
532 enum ttm_bo_type type,
533 struct ttm_placement *placement,
534 uint32_t page_alignment,
536 struct vm_object *persistent_swap_storage,
537 struct ttm_buffer_object **p_bo);
540 * ttm_bo_check_placement
542 * @bo: the buffer object.
543 * @placement: placements
545 * Performs minimal validity checking on an intended change of
548 * -EINVAL: Intended change is invalid or not allowed.
550 extern int ttm_bo_check_placement(struct ttm_buffer_object *bo,
551 struct ttm_placement *placement);
556 * @bdev: Pointer to a ttm_bo_device struct.
557 * @mem_type: The memory type.
558 * @p_size: size managed area in pages.
560 * Initialize a manager for a given memory type.
561 * Note: if part of driver firstopen, it must be protected from a
562 * potentially racing lastclose.
564 * -EINVAL: invalid size or memory type.
565 * -ENOMEM: Not enough memory.
566 * May also return driver-specified errors.
569 extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
570 unsigned long p_size);
574 * @bdev: Pointer to a ttm_bo_device struct.
575 * @mem_type: The memory type.
577 * Take down a manager for a given memory type after first walking
578 * the LRU list to evict any buffers left alive.
580 * Normally, this function is part of lastclose() or unload(), and at that
581 * point there shouldn't be any buffers left created by user-space, since
582 * there should've been removed by the file descriptor release() method.
583 * However, before this function is run, make sure to signal all sync objects,
584 * and verify that the delayed delete queue is empty. The driver must also
585 * make sure that there are no NO_EVICT buffers present in this memory type
586 * when the call is made.
588 * If this function is part of a VT switch, the caller must make sure that
589 * there are no appications currently validating buffers before this
590 * function is called. The caller can do that by first taking the
591 * struct ttm_bo_device::ttm_lock in write mode.
594 * -EINVAL: invalid or uninitialized memory type.
595 * -EBUSY: There are still buffers left in this memory type.
598 extern int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
603 * @bdev: Pointer to a ttm_bo_device struct.
604 * @mem_type: The memory type.
606 * Evicts all buffers on the lru list of the memory type.
607 * This is normally part of a VT switch or an
608 * out-of-memory-space-due-to-fragmentation handler.
609 * The caller must make sure that there are no other processes
610 * currently validating buffers, and can do that by taking the
611 * struct ttm_bo_device::ttm_lock in write mode.
614 * -EINVAL: Invalid or uninitialized memory type.
615 * -ERESTARTSYS: The call was interrupted by a signal while waiting to
619 extern int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
622 * ttm_kmap_obj_virtual
624 * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
625 * @is_iomem: Pointer to an integer that on return indicates 1 if the
626 * virtual map is io memory, 0 if normal memory.
628 * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
629 * If *is_iomem is 1 on return, the virtual address points to an io memory area,
630 * that should strictly be accessed by the iowriteXX() and similar functions.
633 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
636 *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
643 * @bo: The buffer object.
644 * @start_page: The first page to map.
645 * @num_pages: Number of pages to map.
646 * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
648 * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
649 * data in the buffer object. The ttm_kmap_obj_virtual function can then be
650 * used to obtain a virtual address to the data.
653 * -ENOMEM: Out of memory.
654 * -EINVAL: Invalid range.
657 extern int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
658 unsigned long num_pages, struct ttm_bo_kmap_obj *map);
663 * @map: Object describing the map to unmap.
665 * Unmaps a kernel map set up by ttm_bo_kmap.
668 extern void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
671 * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
673 * @vma: vma as input from the fbdev mmap method.
674 * @bo: The bo backing the address space. The address space will
675 * have the same size as the bo, and start at offset 0.
677 * This function is intended to be called by the fbdev mmap method
678 * if the fbdev address space is to be backed by a bo.
682 extern int ttm_fbdev_mmap(struct vm_area_struct *vma,
683 struct ttm_buffer_object *bo);
686 * ttm_bo_mmap - mmap out of the ttm device address space.
688 * @filp: filp as input from the mmap method.
689 * @vma: vma as input from the mmap method.
690 * @bdev: Pointer to the ttm_bo_device with the address space manager.
692 * This function is intended to be called by the device mmap method.
693 * if the device address space is to be backed by the bo manager.
696 extern int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
697 struct ttm_bo_device *bdev);
702 * @bdev: Pointer to the struct ttm_bo_device.
703 * @filp: Pointer to the struct file attempting to read / write.
704 * @wbuf: User-space pointer to address of buffer to write. NULL on read.
705 * @rbuf: User-space pointer to address of buffer to read into.
707 * @count: Number of bytes to read / write.
708 * @f_pos: Pointer to current file position.
709 * @write: 1 for read, 0 for write.
711 * This function implements read / write into ttm buffer objects, and is
713 * be called from the fops::read and fops::write method.
715 * See man (2) write, man(2) read. In particular,
716 * the function may return -ERESTARTSYS if
717 * interrupted by a signal.
720 extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
721 const char *wbuf, char *rbuf,
722 size_t count, off_t *f_pos, bool write);
724 extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
727 * ttm_bo_is_reserved - return an indication if a ttm buffer object is reserved
729 * @bo: The buffer object to check.
731 * This function returns an indication if a bo is reserved or not, and should
732 * only be used to print an error when it is not from incorrect api usage, since
733 * there's no guarantee that it is the caller that is holding the reservation.
735 static inline bool ttm_bo_is_reserved(struct ttm_buffer_object *bo)
737 return atomic_read(&bo->reserved);