xref: /openbmc/linux/include/drm/drm_syncobj.h (revision be709d48)
1 /*
2  * Copyright © 2017 Red Hat
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21  * IN THE SOFTWARE.
22  *
23  * Authors:
24  *
25  */
26 #ifndef __DRM_SYNCOBJ_H__
27 #define __DRM_SYNCOBJ_H__
28 
29 #include <linux/dma-fence.h>
30 
31 struct drm_file;
32 
33 /**
34  * struct drm_syncobj - sync object.
35  *
36  * This structure defines a generic sync object which wraps a &dma_fence.
37  */
38 struct drm_syncobj {
39 	/**
40 	 * @refcount: Reference count of this object.
41 	 */
42 	struct kref refcount;
43 	/**
44 	 * @fence:
45 	 * NULL or a pointer to the fence bound to this object.
46 	 *
47 	 * This field should not be used directly. Use drm_syncobj_fence_get()
48 	 * and drm_syncobj_replace_fence() instead.
49 	 */
50 	struct dma_fence __rcu *fence;
51 	/**
52 	 * @cb_list: List of callbacks to call when the &fence gets replaced.
53 	 */
54 	struct list_head cb_list;
55 	/**
56 	 * @lock: Protects &cb_list and write-locks &fence.
57 	 */
58 	spinlock_t lock;
59 	/**
60 	 * @file: A file backing for this syncobj.
61 	 */
62 	struct file *file;
63 };
64 
65 void drm_syncobj_free(struct kref *kref);
66 
67 /**
68  * drm_syncobj_get - acquire a syncobj reference
69  * @obj: sync object
70  *
71  * This acquires an additional reference to @obj. It is illegal to call this
72  * without already holding a reference. No locks required.
73  */
74 static inline void
75 drm_syncobj_get(struct drm_syncobj *obj)
76 {
77 	kref_get(&obj->refcount);
78 }
79 
80 /**
81  * drm_syncobj_put - release a reference to a sync object.
82  * @obj: sync object.
83  */
84 static inline void
85 drm_syncobj_put(struct drm_syncobj *obj)
86 {
87 	kref_put(&obj->refcount, drm_syncobj_free);
88 }
89 
90 /**
91  * drm_syncobj_fence_get - get a reference to a fence in a sync object
92  * @syncobj: sync object.
93  *
94  * This acquires additional reference to &drm_syncobj.fence contained in @obj,
95  * if not NULL. It is illegal to call this without already holding a reference.
96  * No locks required.
97  *
98  * Returns:
99  * Either the fence of @obj or NULL if there's none.
100  */
101 static inline struct dma_fence *
102 drm_syncobj_fence_get(struct drm_syncobj *syncobj)
103 {
104 	struct dma_fence *fence;
105 
106 	rcu_read_lock();
107 	fence = dma_fence_get_rcu_safe(&syncobj->fence);
108 	rcu_read_unlock();
109 
110 	return fence;
111 }
112 
113 struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
114 				     u32 handle);
115 void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
116 			       struct dma_fence *fence);
117 int drm_syncobj_find_fence(struct drm_file *file_private,
118 			   u32 handle, u64 point, u64 flags,
119 			   struct dma_fence **fence);
120 void drm_syncobj_free(struct kref *kref);
121 int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
122 		       struct dma_fence *fence);
123 int drm_syncobj_get_handle(struct drm_file *file_private,
124 			   struct drm_syncobj *syncobj, u32 *handle);
125 int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);
126 
127 #endif
128