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      1 /*	$NetBSD: drm_syncobj.h,v 1.2 2021/12/18 23:45:46 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright  2017 Red Hat
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice (including the next
     14  * paragraph) shall be included in all copies or substantial portions of the
     15  * Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     23  * IN THE SOFTWARE.
     24  *
     25  * Authors:
     26  *
     27  */
     28 #ifndef __DRM_SYNCOBJ_H__
     29 #define __DRM_SYNCOBJ_H__
     30 
     31 #include <linux/dma-fence.h>
     32 #include <linux/dma-fence-chain.h>
     33 
     34 struct drm_file;
     35 
     36 /**
     37  * struct drm_syncobj - sync object.
     38  *
     39  * This structure defines a generic sync object which wraps a &dma_fence.
     40  */
     41 struct drm_syncobj {
     42 	/**
     43 	 * @refcount: Reference count of this object.
     44 	 */
     45 	struct kref refcount;
     46 	/**
     47 	 * @fence:
     48 	 * NULL or a pointer to the fence bound to this object.
     49 	 *
     50 	 * This field should not be used directly. Use drm_syncobj_fence_get()
     51 	 * and drm_syncobj_replace_fence() instead.
     52 	 */
     53 	struct dma_fence __rcu *fence;
     54 	/**
     55 	 * @cb_list: List of callbacks to call when the &fence gets replaced.
     56 	 */
     57 	struct list_head cb_list;
     58 	/**
     59 	 * @lock: Protects &cb_list and write-locks &fence.
     60 	 */
     61 	spinlock_t lock;
     62 	/**
     63 	 * @file: A file backing for this syncobj.
     64 	 */
     65 	struct file *file;
     66 };
     67 
     68 void drm_syncobj_free(struct kref *kref);
     69 
     70 /**
     71  * drm_syncobj_get - acquire a syncobj reference
     72  * @obj: sync object
     73  *
     74  * This acquires an additional reference to @obj. It is illegal to call this
     75  * without already holding a reference. No locks required.
     76  */
     77 static inline void
     78 drm_syncobj_get(struct drm_syncobj *obj)
     79 {
     80 	kref_get(&obj->refcount);
     81 }
     82 
     83 /**
     84  * drm_syncobj_put - release a reference to a sync object.
     85  * @obj: sync object.
     86  */
     87 static inline void
     88 drm_syncobj_put(struct drm_syncobj *obj)
     89 {
     90 	kref_put(&obj->refcount, drm_syncobj_free);
     91 }
     92 
     93 /**
     94  * drm_syncobj_fence_get - get a reference to a fence in a sync object
     95  * @syncobj: sync object.
     96  *
     97  * This acquires additional reference to &drm_syncobj.fence contained in @obj,
     98  * if not NULL. It is illegal to call this without already holding a reference.
     99  * No locks required.
    100  *
    101  * Returns:
    102  * Either the fence of @obj or NULL if there's none.
    103  */
    104 static inline struct dma_fence *
    105 drm_syncobj_fence_get(struct drm_syncobj *syncobj)
    106 {
    107 	struct dma_fence *fence;
    108 
    109 	rcu_read_lock();
    110 	fence = dma_fence_get_rcu_safe(&syncobj->fence);
    111 	rcu_read_unlock();
    112 
    113 	return fence;
    114 }
    115 
    116 struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
    117 				     u32 handle);
    118 void drm_syncobj_add_point(struct drm_syncobj *syncobj,
    119 			   struct dma_fence_chain *chain,
    120 			   struct dma_fence *fence,
    121 			   uint64_t point);
    122 void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
    123 			       struct dma_fence *fence);
    124 int drm_syncobj_find_fence(struct drm_file *file_private,
    125 			   u32 handle, u64 point, u64 flags,
    126 			   struct dma_fence **fence);
    127 void drm_syncobj_free(struct kref *kref);
    128 int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
    129 		       struct dma_fence *fence);
    130 int drm_syncobj_get_handle(struct drm_file *file_private,
    131 			   struct drm_syncobj *syncobj, u32 *handle);
    132 int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);
    133 
    134 #endif
    135