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_syncobj_cb;
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 typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,
66 				   struct drm_syncobj_cb *cb);
67 
68 /**
69  * struct drm_syncobj_cb - callback for drm_syncobj_add_callback
70  * @node: used by drm_syncob_add_callback to append this struct to
71  *	  &drm_syncobj.cb_list
72  * @func: drm_syncobj_func_t to call
73  *
74  * This struct will be initialized by drm_syncobj_add_callback, additional
75  * data can be passed along by embedding drm_syncobj_cb in another struct.
76  * The callback will get called the next time drm_syncobj_replace_fence is
77  * called.
78  */
79 struct drm_syncobj_cb {
80 	struct list_head node;
81 	drm_syncobj_func_t func;
82 };
83 
84 void drm_syncobj_free(struct kref *kref);
85 
86 /**
87  * drm_syncobj_get - acquire a syncobj reference
88  * @obj: sync object
89  *
90  * This acquires an additional reference to @obj. It is illegal to call this
91  * without already holding a reference. No locks required.
92  */
93 static inline void
drm_syncobj_get(struct drm_syncobj * obj)94 drm_syncobj_get(struct drm_syncobj *obj)
95 {
96 	kref_get(&obj->refcount);
97 }
98 
99 /**
100  * drm_syncobj_put - release a reference to a sync object.
101  * @obj: sync object.
102  */
103 static inline void
drm_syncobj_put(struct drm_syncobj * obj)104 drm_syncobj_put(struct drm_syncobj *obj)
105 {
106 	kref_put(&obj->refcount, drm_syncobj_free);
107 }
108 
109 /**
110  * drm_syncobj_fence_get - get a reference to a fence in a sync object
111  * @syncobj: sync object.
112  *
113  * This acquires additional reference to &drm_syncobj.fence contained in @obj,
114  * if not NULL. It is illegal to call this without already holding a reference.
115  * No locks required.
116  *
117  * Returns:
118  * Either the fence of @obj or NULL if there's none.
119  */
120 static inline struct dma_fence *
drm_syncobj_fence_get(struct drm_syncobj * syncobj)121 drm_syncobj_fence_get(struct drm_syncobj *syncobj)
122 {
123 	struct dma_fence *fence;
124 
125 	rcu_read_lock();
126 	fence = dma_fence_get_rcu_safe(&syncobj->fence);
127 	rcu_read_unlock();
128 
129 	return fence;
130 }
131 
132 struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
133 				     u32 handle);
134 void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
135 			      struct drm_syncobj_cb *cb,
136 			      drm_syncobj_func_t func);
137 void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
138 				 struct drm_syncobj_cb *cb);
139 void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
140 			       struct dma_fence *fence);
141 int drm_syncobj_find_fence(struct drm_file *file_private,
142 			   u32 handle,
143 			   struct dma_fence **fence);
144 void drm_syncobj_free(struct kref *kref);
145 int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
146 		       struct dma_fence *fence);
147 int drm_syncobj_get_handle(struct drm_file *file_private,
148 			   struct drm_syncobj *syncobj, u32 *handle);
149 int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);
150 
151 #endif
152