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
7 * copy of this software and associated documentation files (the
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26 **************************************************************************/
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
31 #ifndef _TTM_BO_API_H_
32 #define _TTM_BO_API_H_
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>
41 #include <linux/bitmap.h>
42 #include <linux/reservation.h>
53 * struct ttm_bus_placement
55 * @addr: mapped virtual address
56 * @base: bus base address
57 * @is_iomem: is this io memory ?
59 * @offset: offset from the base address
60 * @io_reserved_vm: The VM system has a refcount in @io_reserved_count
61 * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve
63 * Structure indicating the bus placement of an object.
65 struct ttm_bus_placement {
72 uint64_t io_reserved_count;
79 * @mm_node: Memory manager node.
80 * @size: Requested size of memory region.
81 * @num_pages: Actual size of memory region in pages.
82 * @page_alignment: Page alignment.
83 * @placement: Placement flags.
84 * @bus: Placement on io bus accessible to the CPU
86 * Structure indicating the placement and space resources used by a
94 unsigned long num_pages;
95 uint32_t page_alignment;
98 struct ttm_bus_placement bus;
104 * @ttm_bo_type_device: These are 'normal' buffers that can
105 * be mmapped by user space. Each of these bos occupy a slot in the
106 * device address space, that can be used for normal vm operations.
108 * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
109 * but they cannot be accessed from user-space. For kernel-only use.
111 * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another
124 * struct ttm_buffer_object
126 * @bdev: Pointer to the buffer object device structure.
127 * @type: The bo type.
128 * @destroy: Destruction function. If NULL, kfree is used.
129 * @num_pages: Actual number of pages.
130 * @acc_size: Accounted size for this object.
131 * @kref: Reference count of this buffer object. When this refcount reaches
132 * zero, the object is put on the delayed delete list.
133 * @list_kref: List reference count of this buffer object. This member is
134 * used to avoid destruction while the buffer object is still on a list.
135 * Lru lists may keep one refcount, the delayed delete list, and kref != 0
136 * keeps one refcount. When this refcount reaches zero,
137 * the object is destroyed.
138 * @mem: structure describing current placement.
139 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
140 * pinned in physical memory. If this behaviour is not desired, this member
141 * holds a pointer to a persistent shmem object.
142 * @ttm: TTM structure holding system pages.
143 * @evicted: Whether the object was evicted without user-space knowing.
144 * @cpu_writes: For synchronization. Number of cpu writers.
145 * @lru: List head for the lru list.
146 * @ddestroy: List head for the delayed destroy list.
147 * @swap: List head for swap LRU list.
148 * @moving: Fence set when BO is moving
149 * @vma_node: Address space manager node.
150 * @offset: The current GPU offset, which can have different meanings
151 * depending on the memory type. For SYSTEM type memory, it should be 0.
152 * @cur_placement: Hint of current placement.
153 * @wu_mutex: Wait unreserved mutex.
155 * Base class for TTM buffer object, that deals with data placement and CPU
156 * mappings. GPU mappings are really up to the driver, but for simpler GPUs
157 * the driver can usually use the placement offset @offset directly as the
158 * GPU virtual address. For drivers implementing multiple
159 * GPU memory manager contexts, the driver should manage the address space
160 * in these contexts separately and use these objects to get the correct
161 * placement and caching for these GPU maps. This makes it possible to use
162 * these objects for even quite elaborate memory management schemes.
163 * The destroy member, the API visibility of this object makes it possible
164 * to derive driver specific types.
167 struct ttm_buffer_object {
169 * Members constant at init.
172 struct ttm_bo_global *glob;
173 struct ttm_bo_device *bdev;
174 enum ttm_bo_type type;
175 void (*destroy) (struct ttm_buffer_object *);
176 unsigned long num_pages;
180 * Members not needing protection.
184 struct kref list_kref;
187 * Members protected by the bo::resv::reserved lock.
190 struct ttm_mem_reg mem;
191 struct file *persistent_swap_storage;
196 * Members protected by the bo::reserved lock only when written to.
199 atomic_t cpu_writers;
202 * Members protected by the bdev::lru_lock.
205 struct list_head lru;
206 struct list_head ddestroy;
207 struct list_head swap;
208 struct list_head io_reserve_lru;
211 * Members protected by a bo reservation.
214 struct dma_fence *moving;
216 struct drm_vma_offset_node vma_node;
221 * Special members that are protected by the reserve lock
222 * and the bo::lock when written to. Can be read with
223 * either of these locks held.
226 uint64_t offset; /* GPU address space is independent of CPU word size */
227 uint32_t cur_placement;
231 struct reservation_object *resv;
232 struct reservation_object ttm_resv;
233 struct mutex wu_mutex;
237 * struct ttm_bo_kmap_obj
239 * @virtual: The current kernel virtual address.
240 * @page: The page when kmap'ing a single page.
241 * @bo_kmap_type: Type of bo_kmap.
243 * Object describing a kernel mapping. Since a TTM bo may be located
244 * in various memory types with various caching policies, the
245 * mapping can either be an ioremap, a vmap, a kmap or part of a
249 #define TTM_BO_MAP_IOMEM_MASK 0x80
250 struct ttm_bo_kmap_obj {
254 ttm_bo_map_iomap = 1 | TTM_BO_MAP_IOMEM_MASK,
257 ttm_bo_map_premapped = 4 | TTM_BO_MAP_IOMEM_MASK,
259 struct ttm_buffer_object *bo;
263 * ttm_bo_reference - reference a struct ttm_buffer_object
265 * @bo: The buffer object.
267 * Returns a refcounted pointer to a buffer object.
270 static inline struct ttm_buffer_object *
271 ttm_bo_reference(struct ttm_buffer_object *bo)
278 * ttm_bo_wait - wait for buffer idle.
280 * @bo: The buffer object.
281 * @interruptible: Use interruptible wait.
282 * @no_wait: Return immediately if buffer is busy.
284 * This function must be called with the bo::mutex held, and makes
285 * sure any previous rendering to the buffer is completed.
286 * Note: It might be necessary to block validations before the
287 * wait by reserving the buffer.
288 * Returns -EBUSY if no_wait is true and the buffer is busy.
289 * Returns -ERESTARTSYS if interrupted by a signal.
291 extern int ttm_bo_wait(struct ttm_buffer_object *bo,
292 bool interruptible, bool no_wait);
295 * ttm_bo_mem_compat - Check if proposed placement is compatible with a bo
297 * @placement: Return immediately if buffer is busy.
298 * @mem: The struct ttm_mem_reg indicating the region where the bo resides
299 * @new_flags: Describes compatible placement found
301 * Returns true if the placement is compatible
303 extern bool ttm_bo_mem_compat(struct ttm_placement *placement,
304 struct ttm_mem_reg *mem,
305 uint32_t *new_flags);
310 * @bo: The buffer object.
311 * @placement: Proposed placement for the buffer object.
312 * @interruptible: Sleep interruptible if sleeping.
313 * @no_wait_gpu: Return immediately if the GPU is busy.
315 * Changes placement and caching policy of the buffer object
316 * according proposed placement.
318 * -EINVAL on invalid proposed placement.
319 * -ENOMEM on out-of-memory condition.
320 * -EBUSY if no_wait is true and buffer busy.
321 * -ERESTARTSYS if interrupted by a signal.
323 extern int ttm_bo_validate(struct ttm_buffer_object *bo,
324 struct ttm_placement *placement,
331 * @bo: The buffer object.
333 * Unreference and clear a pointer to a buffer object.
335 extern void ttm_bo_unref(struct ttm_buffer_object **bo);
340 * @bo: The buffer object.
342 * Add this bo to the relevant mem type lru and, if it's backed by
343 * system pages (ttms) to the swap list.
344 * This function must be called with struct ttm_bo_global::lru_lock held, and
345 * is typically called immediately prior to unreserving a bo.
347 extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
350 * ttm_bo_del_from_lru
352 * @bo: The buffer object.
354 * Remove this bo from all lru lists used to lookup and reserve an object.
355 * This function must be called with struct ttm_bo_global::lru_lock held,
356 * and is usually called just immediately after the bo has been reserved to
357 * avoid recursive reservation from lru lists.
359 extern void ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
362 * ttm_bo_move_to_lru_tail
364 * @bo: The buffer object.
366 * Move this BO to the tail of all lru lists used to lookup and reserve an
367 * object. This function must be called with struct ttm_bo_global::lru_lock
368 * held, and is used to make a BO less likely to be considered for eviction.
370 extern void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo);
373 * ttm_bo_lock_delayed_workqueue
375 * Prevent the delayed workqueue from running.
377 * True if the workqueue was queued at the time
379 extern int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
382 * ttm_bo_unlock_delayed_workqueue
384 * Allows the delayed workqueue to run.
386 extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
390 * ttm_bo_eviction_valuable
392 * @bo: The buffer object to evict
393 * @place: the placement we need to make room for
395 * Check if it is valuable to evict the BO to make room for the given placement.
397 bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
398 const struct ttm_place *place);
401 * ttm_bo_synccpu_write_grab
403 * @bo: The buffer object:
404 * @no_wait: Return immediately if buffer is busy.
406 * Synchronizes a buffer object for CPU RW access. This means
407 * command submission that affects the buffer will return -EBUSY
408 * until ttm_bo_synccpu_write_release is called.
411 * -EBUSY if the buffer is busy and no_wait is true.
412 * -ERESTARTSYS if interrupted by a signal.
415 ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
418 * ttm_bo_synccpu_write_release:
420 * @bo : The buffer object.
422 * Releases a synccpu lock.
424 extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
429 * @bdev: Pointer to a ttm_bo_device struct.
430 * @bo_size: size of the buffer object in byte.
431 * @struct_size: size of the structure holding buffer object datas
433 * Returns size to account for a buffer object
435 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
436 unsigned long bo_size,
437 unsigned struct_size);
438 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
439 unsigned long bo_size,
440 unsigned struct_size);
445 * @bdev: Pointer to a ttm_bo_device struct.
446 * @bo: Pointer to a ttm_buffer_object to be initialized.
447 * @size: Requested size of buffer object.
448 * @type: Requested type of buffer object.
449 * @flags: Initial placement flags.
450 * @page_alignment: Data alignment in pages.
451 * @interruptible: If needing to sleep to wait for GPU resources,
452 * sleep interruptible.
453 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
454 * pinned in physical memory. If this behaviour is not desired, this member
455 * holds a pointer to a persistent shmem object. Typically, this would
456 * point to the shmem object backing a GEM object if TTM is used to back a
457 * GEM user interface.
458 * @acc_size: Accounted size for this object.
459 * @resv: Pointer to a reservation_object, or NULL to let ttm allocate one.
460 * @destroy: Destroy function. Use NULL for kfree().
462 * This function initializes a pre-allocated struct ttm_buffer_object.
463 * As this object may be part of a larger structure, this function,
464 * together with the @destroy function,
465 * enables driver-specific objects derived from a ttm_buffer_object.
466 * On successful return, the object kref and list_kref are set to 1.
467 * If a failure occurs, the function will call the @destroy function, or
468 * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
469 * illegal and will likely cause memory corruption.
472 * -ENOMEM: Out of memory.
473 * -EINVAL: Invalid placement flags.
474 * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
477 extern int ttm_bo_init(struct ttm_bo_device *bdev,
478 struct ttm_buffer_object *bo,
480 enum ttm_bo_type type,
481 struct ttm_placement *placement,
482 uint32_t page_alignment,
484 struct file *persistent_swap_storage,
487 struct reservation_object *resv,
488 void (*destroy) (struct ttm_buffer_object *));
493 * @bdev: Pointer to a ttm_bo_device struct.
494 * @size: Requested size of buffer object.
495 * @type: Requested type of buffer object.
496 * @placement: Initial placement.
497 * @page_alignment: Data alignment in pages.
498 * @interruptible: If needing to sleep while waiting for GPU resources,
499 * sleep interruptible.
500 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
501 * pinned in physical memory. If this behaviour is not desired, this member
502 * holds a pointer to a persistent shmem object. Typically, this would
503 * point to the shmem object backing a GEM object if TTM is used to back a
504 * GEM user interface.
505 * @p_bo: On successful completion *p_bo points to the created object.
507 * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
508 * on that object. The destroy function is set to kfree().
510 * -ENOMEM: Out of memory.
511 * -EINVAL: Invalid placement flags.
512 * -ERESTARTSYS: Interrupted by signal while waiting for resources.
515 extern int ttm_bo_create(struct ttm_bo_device *bdev,
517 enum ttm_bo_type type,
518 struct ttm_placement *placement,
519 uint32_t page_alignment,
521 struct file *persistent_swap_storage,
522 struct ttm_buffer_object **p_bo);
527 * @bdev: Pointer to a ttm_bo_device struct.
528 * @mem_type: The memory type.
529 * @p_size: size managed area in pages.
531 * Initialize a manager for a given memory type.
532 * Note: if part of driver firstopen, it must be protected from a
533 * potentially racing lastclose.
535 * -EINVAL: invalid size or memory type.
536 * -ENOMEM: Not enough memory.
537 * May also return driver-specified errors.
540 extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
541 unsigned long p_size);
545 * @bdev: Pointer to a ttm_bo_device struct.
546 * @mem_type: The memory type.
548 * Take down a manager for a given memory type after first walking
549 * the LRU list to evict any buffers left alive.
551 * Normally, this function is part of lastclose() or unload(), and at that
552 * point there shouldn't be any buffers left created by user-space, since
553 * there should've been removed by the file descriptor release() method.
554 * However, before this function is run, make sure to signal all sync objects,
555 * and verify that the delayed delete queue is empty. The driver must also
556 * make sure that there are no NO_EVICT buffers present in this memory type
557 * when the call is made.
559 * If this function is part of a VT switch, the caller must make sure that
560 * there are no appications currently validating buffers before this
561 * function is called. The caller can do that by first taking the
562 * struct ttm_bo_device::ttm_lock in write mode.
565 * -EINVAL: invalid or uninitialized memory type.
566 * -EBUSY: There are still buffers left in this memory type.
569 extern int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
574 * @bdev: Pointer to a ttm_bo_device struct.
575 * @mem_type: The memory type.
577 * Evicts all buffers on the lru list of the memory type.
578 * This is normally part of a VT switch or an
579 * out-of-memory-space-due-to-fragmentation handler.
580 * The caller must make sure that there are no other processes
581 * currently validating buffers, and can do that by taking the
582 * struct ttm_bo_device::ttm_lock in write mode.
585 * -EINVAL: Invalid or uninitialized memory type.
586 * -ERESTARTSYS: The call was interrupted by a signal while waiting to
590 extern int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
593 * ttm_kmap_obj_virtual
595 * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
596 * @is_iomem: Pointer to an integer that on return indicates 1 if the
597 * virtual map is io memory, 0 if normal memory.
599 * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
600 * If *is_iomem is 1 on return, the virtual address points to an io memory area,
601 * that should strictly be accessed by the iowriteXX() and similar functions.
604 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
607 *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
614 * @bo: The buffer object.
615 * @start_page: The first page to map.
616 * @num_pages: Number of pages to map.
617 * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
619 * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
620 * data in the buffer object. The ttm_kmap_obj_virtual function can then be
621 * used to obtain a virtual address to the data.
624 * -ENOMEM: Out of memory.
625 * -EINVAL: Invalid range.
628 extern int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
629 unsigned long num_pages, struct ttm_bo_kmap_obj *map);
634 * @map: Object describing the map to unmap.
636 * Unmaps a kernel map set up by ttm_bo_kmap.
639 extern void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
642 * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
644 * @vma: vma as input from the fbdev mmap method.
645 * @bo: The bo backing the address space. The address space will
646 * have the same size as the bo, and start at offset 0.
648 * This function is intended to be called by the fbdev mmap method
649 * if the fbdev address space is to be backed by a bo.
652 extern int ttm_fbdev_mmap(struct vm_area_struct *vma,
653 struct ttm_buffer_object *bo);
656 * ttm_bo_mmap - mmap out of the ttm device address space.
658 * @filp: filp as input from the mmap method.
659 * @vma: vma as input from the mmap method.
660 * @bdev: Pointer to the ttm_bo_device with the address space manager.
662 * This function is intended to be called by the device mmap method.
663 * if the device address space is to be backed by the bo manager.
666 extern int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
667 struct ttm_bo_device *bdev);
672 * @bdev: Pointer to the struct ttm_bo_device.
673 * @filp: Pointer to the struct file attempting to read / write.
674 * @wbuf: User-space pointer to address of buffer to write. NULL on read.
675 * @rbuf: User-space pointer to address of buffer to read into.
677 * @count: Number of bytes to read / write.
678 * @f_pos: Pointer to current file position.
679 * @write: 1 for read, 0 for write.
681 * This function implements read / write into ttm buffer objects, and is
683 * be called from the fops::read and fops::write method.
685 * See man (2) write, man(2) read. In particular,
686 * the function may return -ERESTARTSYS if
687 * interrupted by a signal.
690 extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
691 const char __user *wbuf, char __user *rbuf,
692 size_t count, loff_t *f_pos, bool write);
694 extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
695 extern int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo);