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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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_gem.h>
35 #include <drm/drm_hashtab.h>
36 #include <drm/drm_vma_manager.h>
37 #include <linux/kref.h>
38 #include <linux/list.h>
39 #include <linux/wait.h>
40 #include <linux/mutex.h>
42 #include <linux/bitmap.h>
43 #include <linux/dma-resv.h>
55 struct ttm_lru_bulk_move;
58 * struct ttm_bus_placement
60 * @addr: mapped virtual address
61 * @base: bus base address
62 * @is_iomem: is this io memory ?
64 * @offset: offset from the base address
65 * @io_reserved_vm: The VM system has a refcount in @io_reserved_count
66 * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve
68 * Structure indicating the bus placement of an object.
70 struct ttm_bus_placement {
77 uint64_t io_reserved_count;
84 * @mm_node: Memory manager node.
85 * @size: Requested size of memory region.
86 * @num_pages: Actual size of memory region in pages.
87 * @page_alignment: Page alignment.
88 * @placement: Placement flags.
89 * @bus: Placement on io bus accessible to the CPU
91 * Structure indicating the placement and space resources used by a
99 unsigned long num_pages;
100 uint32_t page_alignment;
103 struct ttm_bus_placement bus;
109 * @ttm_bo_type_device: These are 'normal' buffers that can
110 * be mmapped by user space. Each of these bos occupy a slot in the
111 * device address space, that can be used for normal vm operations.
113 * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
114 * but they cannot be accessed from user-space. For kernel-only use.
116 * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another
129 * struct ttm_buffer_object
131 * @base: drm_gem_object superclass data.
132 * @bdev: Pointer to the buffer object device structure.
133 * @type: The bo type.
134 * @destroy: Destruction function. If NULL, kfree is used.
135 * @num_pages: Actual number of pages.
136 * @acc_size: Accounted size for this object.
137 * @kref: Reference count of this buffer object. When this refcount reaches
138 * zero, the object is put on the delayed delete list.
139 * @list_kref: List reference count of this buffer object. This member is
140 * used to avoid destruction while the buffer object is still on a list.
141 * Lru lists may keep one refcount, the delayed delete list, and kref != 0
142 * keeps one refcount. When this refcount reaches zero,
143 * the object is destroyed.
144 * @mem: structure describing current placement.
145 * @persistent_swap_storage: Usually the swap storage is deleted for buffers
146 * pinned in physical memory. If this behaviour is not desired, this member
147 * holds a pointer to a persistent shmem object.
148 * @ttm: TTM structure holding system pages.
149 * @evicted: Whether the object was evicted without user-space knowing.
150 * @cpu_writes: For synchronization. Number of cpu writers.
151 * @lru: List head for the lru list.
152 * @ddestroy: List head for the delayed destroy list.
153 * @swap: List head for swap LRU list.
154 * @moving: Fence set when BO is moving
155 * @offset: The current GPU offset, which can have different meanings
156 * depending on the memory type. For SYSTEM type memory, it should be 0.
157 * @cur_placement: Hint of current placement.
158 * @wu_mutex: Wait unreserved mutex.
160 * Base class for TTM buffer object, that deals with data placement and CPU
161 * mappings. GPU mappings are really up to the driver, but for simpler GPUs
162 * the driver can usually use the placement offset @offset directly as the
163 * GPU virtual address. For drivers implementing multiple
164 * GPU memory manager contexts, the driver should manage the address space
165 * in these contexts separately and use these objects to get the correct
166 * placement and caching for these GPU maps. This makes it possible to use
167 * these objects for even quite elaborate memory management schemes.
168 * The destroy member, the API visibility of this object makes it possible
169 * to derive driver specific types.
172 struct ttm_buffer_object {
173 struct drm_gem_object base;
176 * Members constant at init.
179 struct ttm_bo_device *bdev;
180 enum ttm_bo_type type;
181 void (*destroy) (struct ttm_buffer_object *);
182 unsigned long num_pages;
186 * Members not needing protection.
190 struct kref list_kref;
193 * Members protected by the bo::resv::reserved lock.
196 struct ttm_mem_reg mem;
197 struct file *persistent_swap_storage;
202 * Members protected by the bo::reserved lock only when written to.
205 atomic_t cpu_writers;
208 * Members protected by the bdev::lru_lock.
211 struct list_head lru;
212 struct list_head ddestroy;
213 struct list_head swap;
214 struct list_head io_reserve_lru;
217 * Members protected by a bo reservation.
220 struct dma_fence *moving;
224 * Special members that are protected by the reserve lock
225 * and the bo::lock when written to. Can be read with
226 * either of these locks held.
229 uint64_t offset; /* GPU address space is independent of CPU word size */
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 * struct ttm_operation_ctx
265 * @interruptible: Sleep interruptible if sleeping.
266 * @no_wait_gpu: Return immediately if the GPU is busy.
267 * @resv: Reservation object to allow reserved evictions with.
268 * @flags: Including the following flags
270 * Context for TTM operations like changing buffer placement or general memory
273 struct ttm_operation_ctx {
276 struct dma_resv *resv;
277 uint64_t bytes_moved;
281 /* Allow eviction of reserved BOs */
282 #define TTM_OPT_FLAG_ALLOW_RES_EVICT 0x1
283 /* when serving page fault or suspend, allow alloc anyway */
284 #define TTM_OPT_FLAG_FORCE_ALLOC 0x2
287 * ttm_bo_get - reference a struct ttm_buffer_object
289 * @bo: The buffer object.
291 static inline void ttm_bo_get(struct ttm_buffer_object *bo)
297 * ttm_bo_get_unless_zero - reference a struct ttm_buffer_object unless
298 * its refcount has already reached zero.
299 * @bo: The buffer object.
301 * Used to reference a TTM buffer object in lookups where the object is removed
302 * from the lookup structure during the destructor and for RCU lookups.
304 * Returns: @bo if the referencing was successful, NULL otherwise.
306 static inline __must_check struct ttm_buffer_object *
307 ttm_bo_get_unless_zero(struct ttm_buffer_object *bo)
309 if (!kref_get_unless_zero(&bo->kref))
315 * ttm_bo_wait - wait for buffer idle.
317 * @bo: The buffer object.
318 * @interruptible: Use interruptible wait.
319 * @no_wait: Return immediately if buffer is busy.
321 * This function must be called with the bo::mutex held, and makes
322 * sure any previous rendering to the buffer is completed.
323 * Note: It might be necessary to block validations before the
324 * wait by reserving the buffer.
325 * Returns -EBUSY if no_wait is true and the buffer is busy.
326 * Returns -ERESTARTSYS if interrupted by a signal.
328 int ttm_bo_wait(struct ttm_buffer_object *bo, bool interruptible, bool no_wait);
331 * ttm_bo_mem_compat - Check if proposed placement is compatible with a bo
333 * @placement: Return immediately if buffer is busy.
334 * @mem: The struct ttm_mem_reg indicating the region where the bo resides
335 * @new_flags: Describes compatible placement found
337 * Returns true if the placement is compatible
339 bool ttm_bo_mem_compat(struct ttm_placement *placement, struct ttm_mem_reg *mem,
340 uint32_t *new_flags);
345 * @bo: The buffer object.
346 * @placement: Proposed placement for the buffer object.
347 * @ctx: validation parameters.
349 * Changes placement and caching policy of the buffer object
350 * according proposed placement.
352 * -EINVAL on invalid proposed placement.
353 * -ENOMEM on out-of-memory condition.
354 * -EBUSY if no_wait is true and buffer busy.
355 * -ERESTARTSYS if interrupted by a signal.
357 int ttm_bo_validate(struct ttm_buffer_object *bo,
358 struct ttm_placement *placement,
359 struct ttm_operation_ctx *ctx);
364 * @bo: The buffer object.
366 * Unreference a buffer object.
368 void ttm_bo_put(struct ttm_buffer_object *bo);
373 * @bo: The buffer object.
375 * Add this bo to the relevant mem type lru and, if it's backed by
376 * system pages (ttms) to the swap list.
377 * This function must be called with struct ttm_bo_global::lru_lock held, and
378 * is typically called immediately prior to unreserving a bo.
380 void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
383 * ttm_bo_del_from_lru
385 * @bo: The buffer object.
387 * Remove this bo from all lru lists used to lookup and reserve an object.
388 * This function must be called with struct ttm_bo_global::lru_lock held,
389 * and is usually called just immediately after the bo has been reserved to
390 * avoid recursive reservation from lru lists.
392 void ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
395 * ttm_bo_move_to_lru_tail
397 * @bo: The buffer object.
398 * @bulk: optional bulk move structure to remember BO positions
400 * Move this BO to the tail of all lru lists used to lookup and reserve an
401 * object. This function must be called with struct ttm_bo_global::lru_lock
402 * held, and is used to make a BO less likely to be considered for eviction.
404 void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
405 struct ttm_lru_bulk_move *bulk);
408 * ttm_bo_bulk_move_lru_tail
410 * @bulk: bulk move structure
412 * Bulk move BOs to the LRU tail, only valid to use when driver makes sure that
413 * BO order never changes. Should be called with ttm_bo_global::lru_lock held.
415 void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk);
418 * ttm_bo_lock_delayed_workqueue
420 * Prevent the delayed workqueue from running.
422 * True if the workqueue was queued at the time
424 int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
427 * ttm_bo_unlock_delayed_workqueue
429 * Allows the delayed workqueue to run.
431 void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev, int resched);
434 * ttm_bo_eviction_valuable
436 * @bo: The buffer object to evict
437 * @place: the placement we need to make room for
439 * Check if it is valuable to evict the BO to make room for the given placement.
441 bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
442 const struct ttm_place *place);
445 * ttm_bo_synccpu_write_grab
447 * @bo: The buffer object:
448 * @no_wait: Return immediately if buffer is busy.
450 * Synchronizes a buffer object for CPU RW access. This means
451 * command submission that affects the buffer will return -EBUSY
452 * until ttm_bo_synccpu_write_release is called.
455 * -EBUSY if the buffer is busy and no_wait is true.
456 * -ERESTARTSYS if interrupted by a signal.
458 int ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
461 * ttm_bo_synccpu_write_release:
463 * @bo : The buffer object.
465 * Releases a synccpu lock.
467 void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
472 * @bdev: Pointer to a ttm_bo_device struct.
473 * @bo_size: size of the buffer object in byte.
474 * @struct_size: size of the structure holding buffer object datas
476 * Returns size to account for a buffer object
478 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
479 unsigned long bo_size,
480 unsigned struct_size);
481 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
482 unsigned long bo_size,
483 unsigned struct_size);
486 * ttm_bo_init_reserved
488 * @bdev: Pointer to a ttm_bo_device struct.
489 * @bo: Pointer to a ttm_buffer_object to be initialized.
490 * @size: Requested size of buffer object.
491 * @type: Requested type of buffer object.
492 * @flags: Initial placement flags.
493 * @page_alignment: Data alignment in pages.
494 * @ctx: TTM operation context for memory allocation.
495 * @acc_size: Accounted size for this object.
496 * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
497 * @destroy: Destroy function. Use NULL for kfree().
499 * This function initializes a pre-allocated struct ttm_buffer_object.
500 * As this object may be part of a larger structure, this function,
501 * together with the @destroy function,
502 * enables driver-specific objects derived from a ttm_buffer_object.
504 * On successful return, the caller owns an object kref to @bo. The kref and
505 * list_kref are usually set to 1, but note that in some situations, other
506 * tasks may already be holding references to @bo as well.
507 * Furthermore, if resv == NULL, the buffer's reservation lock will be held,
508 * and it is the caller's responsibility to call ttm_bo_unreserve.
510 * If a failure occurs, the function will call the @destroy function, or
511 * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
512 * illegal and will likely cause memory corruption.
515 * -ENOMEM: Out of memory.
516 * -EINVAL: Invalid placement flags.
517 * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
520 int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
521 struct ttm_buffer_object *bo,
523 enum ttm_bo_type type,
524 struct ttm_placement *placement,
525 uint32_t page_alignment,
526 struct ttm_operation_ctx *ctx,
529 struct dma_resv *resv,
530 void (*destroy) (struct ttm_buffer_object *));
535 * @bdev: Pointer to a ttm_bo_device struct.
536 * @bo: Pointer to a ttm_buffer_object to be initialized.
537 * @size: Requested size of buffer object.
538 * @type: Requested type of buffer object.
539 * @flags: Initial placement flags.
540 * @page_alignment: Data alignment in pages.
541 * @interruptible: If needing to sleep to wait for GPU resources,
542 * sleep interruptible.
543 * pinned in physical memory. If this behaviour is not desired, this member
544 * holds a pointer to a persistent shmem object. Typically, this would
545 * point to the shmem object backing a GEM object if TTM is used to back a
546 * GEM user interface.
547 * @acc_size: Accounted size for this object.
548 * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
549 * @destroy: Destroy function. Use NULL for kfree().
551 * This function initializes a pre-allocated struct ttm_buffer_object.
552 * As this object may be part of a larger structure, this function,
553 * together with the @destroy function,
554 * enables driver-specific objects derived from a ttm_buffer_object.
556 * On successful return, the caller owns an object kref to @bo. The kref and
557 * list_kref are usually set to 1, but note that in some situations, other
558 * tasks may already be holding references to @bo as well.
560 * If a failure occurs, the function will call the @destroy function, or
561 * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
562 * illegal and will likely cause memory corruption.
565 * -ENOMEM: Out of memory.
566 * -EINVAL: Invalid placement flags.
567 * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
569 int ttm_bo_init(struct ttm_bo_device *bdev, struct ttm_buffer_object *bo,
570 unsigned long size, enum ttm_bo_type type,
571 struct ttm_placement *placement,
572 uint32_t page_alignment, bool interrubtible, size_t acc_size,
573 struct sg_table *sg, struct dma_resv *resv,
574 void (*destroy) (struct ttm_buffer_object *));
579 * @bdev: Pointer to a ttm_bo_device struct.
580 * @size: Requested size of buffer object.
581 * @type: Requested type of buffer object.
582 * @placement: Initial placement.
583 * @page_alignment: Data alignment in pages.
584 * @interruptible: If needing to sleep while waiting for GPU resources,
585 * sleep interruptible.
586 * @p_bo: On successful completion *p_bo points to the created object.
588 * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
589 * on that object. The destroy function is set to kfree().
591 * -ENOMEM: Out of memory.
592 * -EINVAL: Invalid placement flags.
593 * -ERESTARTSYS: Interrupted by signal while waiting for resources.
595 int ttm_bo_create(struct ttm_bo_device *bdev, unsigned long size,
596 enum ttm_bo_type type, struct ttm_placement *placement,
597 uint32_t page_alignment, bool interruptible,
598 struct ttm_buffer_object **p_bo);
603 * @bdev: Pointer to a ttm_bo_device struct.
604 * @mem_type: The memory type.
605 * @p_size: size managed area in pages.
607 * Initialize a manager for a given memory type.
608 * Note: if part of driver firstopen, it must be protected from a
609 * potentially racing lastclose.
611 * -EINVAL: invalid size or memory type.
612 * -ENOMEM: Not enough memory.
613 * May also return driver-specified errors.
615 int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
616 unsigned long p_size);
621 * @bdev: Pointer to a ttm_bo_device struct.
622 * @mem_type: The memory type.
624 * Take down a manager for a given memory type after first walking
625 * the LRU list to evict any buffers left alive.
627 * Normally, this function is part of lastclose() or unload(), and at that
628 * point there shouldn't be any buffers left created by user-space, since
629 * there should've been removed by the file descriptor release() method.
630 * However, before this function is run, make sure to signal all sync objects,
631 * and verify that the delayed delete queue is empty. The driver must also
632 * make sure that there are no NO_EVICT buffers present in this memory type
633 * when the call is made.
635 * If this function is part of a VT switch, the caller must make sure that
636 * there are no appications currently validating buffers before this
637 * function is called. The caller can do that by first taking the
638 * struct ttm_bo_device::ttm_lock in write mode.
641 * -EINVAL: invalid or uninitialized memory type.
642 * -EBUSY: There are still buffers left in this memory type.
644 int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
649 * @bdev: Pointer to a ttm_bo_device struct.
650 * @mem_type: The memory type.
652 * Evicts all buffers on the lru list of the memory type.
653 * This is normally part of a VT switch or an
654 * out-of-memory-space-due-to-fragmentation handler.
655 * The caller must make sure that there are no other processes
656 * currently validating buffers, and can do that by taking the
657 * struct ttm_bo_device::ttm_lock in write mode.
660 * -EINVAL: Invalid or uninitialized memory type.
661 * -ERESTARTSYS: The call was interrupted by a signal while waiting to
664 int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
667 * ttm_kmap_obj_virtual
669 * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
670 * @is_iomem: Pointer to an integer that on return indicates 1 if the
671 * virtual map is io memory, 0 if normal memory.
673 * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
674 * If *is_iomem is 1 on return, the virtual address points to an io memory area,
675 * that should strictly be accessed by the iowriteXX() and similar functions.
677 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
680 *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
687 * @bo: The buffer object.
688 * @start_page: The first page to map.
689 * @num_pages: Number of pages to map.
690 * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
692 * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
693 * data in the buffer object. The ttm_kmap_obj_virtual function can then be
694 * used to obtain a virtual address to the data.
697 * -ENOMEM: Out of memory.
698 * -EINVAL: Invalid range.
700 int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
701 unsigned long num_pages, struct ttm_bo_kmap_obj *map);
706 * @map: Object describing the map to unmap.
708 * Unmaps a kernel map set up by ttm_bo_kmap.
710 void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
713 * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
715 * @vma: vma as input from the fbdev mmap method.
716 * @bo: The bo backing the address space. The address space will
717 * have the same size as the bo, and start at offset 0.
719 * This function is intended to be called by the fbdev mmap method
720 * if the fbdev address space is to be backed by a bo.
722 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo);
725 * ttm_bo_mmap - mmap out of the ttm device address space.
727 * @filp: filp as input from the mmap method.
728 * @vma: vma as input from the mmap method.
729 * @bdev: Pointer to the ttm_bo_device with the address space manager.
731 * This function is intended to be called by the device mmap method.
732 * if the device address space is to be backed by the bo manager.
734 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
735 struct ttm_bo_device *bdev);
737 void *ttm_kmap_atomic_prot(struct page *page, pgprot_t prot);
739 void ttm_kunmap_atomic_prot(void *addr, pgprot_t prot);
744 * @bdev: Pointer to the struct ttm_bo_device.
745 * @filp: Pointer to the struct file attempting to read / write.
746 * @wbuf: User-space pointer to address of buffer to write. NULL on read.
747 * @rbuf: User-space pointer to address of buffer to read into.
749 * @count: Number of bytes to read / write.
750 * @f_pos: Pointer to current file position.
751 * @write: 1 for read, 0 for write.
753 * This function implements read / write into ttm buffer objects, and is
755 * be called from the fops::read and fops::write method.
757 * See man (2) write, man(2) read. In particular,
758 * the function may return -ERESTARTSYS if
759 * interrupted by a signal.
761 ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
762 const char __user *wbuf, char __user *rbuf,
763 size_t count, loff_t *f_pos, bool write);
765 int ttm_bo_swapout(struct ttm_bo_global *glob,
766 struct ttm_operation_ctx *ctx);
767 void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
768 int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo);
771 * ttm_bo_uses_embedded_gem_object - check if the given bo uses the
772 * embedded drm_gem_object.
774 * Most ttm drivers are using gem too, so the embedded
775 * ttm_buffer_object.base will be initialized by the driver (before
776 * calling ttm_bo_init). It is also possible to use ttm without gem
777 * though (vmwgfx does that).
779 * This helper will figure whenever a given ttm bo is a gem object too
782 * @bo: The bo to check.
784 static inline bool ttm_bo_uses_embedded_gem_object(struct ttm_buffer_object *bo)
786 return bo->base.dev != NULL;