1 /*
2  * Copyright (c) 2014-2016 Intel Corporation
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 
24 #ifndef __INTEL_FRONTBUFFER_H__
25 #define __INTEL_FRONTBUFFER_H__
26 
27 #include <linux/atomic.h>
28 #include <linux/kref.h>
29 
30 #include "gem/i915_gem_object_types.h"
31 #include "i915_active.h"
32 
33 struct drm_i915_private;
34 
35 enum fb_op_origin {
36 	ORIGIN_CPU = 0,
37 	ORIGIN_CS,
38 	ORIGIN_FLIP,
39 	ORIGIN_DIRTYFB,
40 	ORIGIN_CURSOR_UPDATE,
41 };
42 
43 struct intel_frontbuffer {
44 	struct kref ref;
45 	atomic_t bits;
46 	struct i915_active write;
47 	struct drm_i915_gem_object *obj;
48 	struct rcu_head rcu;
49 };
50 
51 void intel_frontbuffer_flip_prepare(struct drm_i915_private *i915,
52 				    unsigned frontbuffer_bits);
53 void intel_frontbuffer_flip_complete(struct drm_i915_private *i915,
54 				     unsigned frontbuffer_bits);
55 void intel_frontbuffer_flip(struct drm_i915_private *i915,
56 			    unsigned frontbuffer_bits);
57 
58 void intel_frontbuffer_put(struct intel_frontbuffer *front);
59 
60 static inline struct intel_frontbuffer *
61 __intel_frontbuffer_get(const struct drm_i915_gem_object *obj)
62 {
63 	struct intel_frontbuffer *front;
64 
65 	if (likely(!rcu_access_pointer(obj->frontbuffer)))
66 		return NULL;
67 
68 	rcu_read_lock();
69 	do {
70 		front = rcu_dereference(obj->frontbuffer);
71 		if (!front)
72 			break;
73 
74 		if (unlikely(!kref_get_unless_zero(&front->ref)))
75 			continue;
76 
77 		if (likely(front == rcu_access_pointer(obj->frontbuffer)))
78 			break;
79 
80 		intel_frontbuffer_put(front);
81 	} while (1);
82 	rcu_read_unlock();
83 
84 	return front;
85 }
86 
87 struct intel_frontbuffer *
88 intel_frontbuffer_get(struct drm_i915_gem_object *obj);
89 
90 void __intel_fb_invalidate(struct intel_frontbuffer *front,
91 			   enum fb_op_origin origin,
92 			   unsigned int frontbuffer_bits);
93 
94 /**
95  * intel_frontbuffer_invalidate - invalidate frontbuffer object
96  * @front: GEM object to invalidate
97  * @origin: which operation caused the invalidation
98  *
99  * This function gets called every time rendering on the given object starts and
100  * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must
101  * be invalidated. For ORIGIN_CS any subsequent invalidation will be delayed
102  * until the rendering completes or a flip on this frontbuffer plane is
103  * scheduled.
104  */
105 static inline bool intel_frontbuffer_invalidate(struct intel_frontbuffer *front,
106 						enum fb_op_origin origin)
107 {
108 	unsigned int frontbuffer_bits;
109 
110 	if (!front)
111 		return false;
112 
113 	frontbuffer_bits = atomic_read(&front->bits);
114 	if (!frontbuffer_bits)
115 		return false;
116 
117 	__intel_fb_invalidate(front, origin, frontbuffer_bits);
118 	return true;
119 }
120 
121 void __intel_fb_flush(struct intel_frontbuffer *front,
122 		      enum fb_op_origin origin,
123 		      unsigned int frontbuffer_bits);
124 
125 /**
126  * intel_frontbuffer_flush - flush frontbuffer object
127  * @front: GEM object to flush
128  * @origin: which operation caused the flush
129  *
130  * This function gets called every time rendering on the given object has
131  * completed and frontbuffer caching can be started again.
132  */
133 static inline void intel_frontbuffer_flush(struct intel_frontbuffer *front,
134 					   enum fb_op_origin origin)
135 {
136 	unsigned int frontbuffer_bits;
137 
138 	if (!front)
139 		return;
140 
141 	frontbuffer_bits = atomic_read(&front->bits);
142 	if (!frontbuffer_bits)
143 		return;
144 
145 	__intel_fb_flush(front, origin, frontbuffer_bits);
146 }
147 
148 void intel_frontbuffer_track(struct intel_frontbuffer *old,
149 			     struct intel_frontbuffer *new,
150 			     unsigned int frontbuffer_bits);
151 
152 #endif /* __INTEL_FRONTBUFFER_H__ */
153