Android Hardware Abstraction Layer
fb.h
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1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 
18 #ifndef ANDROID_FB_INTERFACE_H
19 #define ANDROID_FB_INTERFACE_H
20 
21 #include <stdint.h>
22 #include <sys/cdefs.h>
23 #include <sys/types.h>
24 
25 #include <cutils/native_handle.h>
26 
27 #include <hardware/hardware.h>
28 
29 __BEGIN_DECLS
30 
31 #define GRALLOC_HARDWARE_FB0 "fb0"
32 
33 /*****************************************************************************/
34 
35 
36 /*****************************************************************************/
37 
38 typedef struct framebuffer_device_t {
40 
41  /* flags describing some attributes of the framebuffer */
42  const uint32_t flags;
43 
44  /* dimensions of the framebuffer in pixels */
45  const uint32_t width;
46  const uint32_t height;
47 
48  /* frambuffer stride in pixels */
49  const int stride;
50 
51  /* framebuffer pixel format */
52  const int format;
53 
54  /* resolution of the framebuffer's display panel in pixel per inch*/
55  const float xdpi;
56  const float ydpi;
57 
58  /* framebuffer's display panel refresh rate in frames per second */
59  const float fps;
60 
61  /* min swap interval supported by this framebuffer */
62  const int minSwapInterval;
63 
64  /* max swap interval supported by this framebuffer */
65  const int maxSwapInterval;
66 
67  /* Number of framebuffers supported*/
68  const int numFramebuffers;
69 
70  int reserved[7];
71 
72  /*
73  * requests a specific swap-interval (same definition than EGL)
74  *
75  * Returns 0 on success or -errno on error.
76  */
77  int (*setSwapInterval)(struct framebuffer_device_t* window,
78  int interval);
79 
80  /*
81  * This hook is OPTIONAL.
82  *
83  * It is non NULL If the framebuffer driver supports "update-on-demand"
84  * and the given rectangle is the area of the screen that gets
85  * updated during (*post)().
86  *
87  * This is useful on devices that are able to DMA only a portion of
88  * the screen to the display panel, upon demand -- as opposed to
89  * constantly refreshing the panel 60 times per second, for instance.
90  *
91  * Only the area defined by this rectangle is guaranteed to be valid, that
92  * is, the driver is not allowed to post anything outside of this
93  * rectangle.
94  *
95  * The rectangle evaluated during (*post)() and specifies which area
96  * of the buffer passed in (*post)() shall to be posted.
97  *
98  * return -EINVAL if width or height <=0, or if left or top < 0
99  */
100  int (*setUpdateRect)(struct framebuffer_device_t* window,
101  int left, int top, int width, int height);
102 
103  /*
104  * Post <buffer> to the display (display it on the screen)
105  * The buffer must have been allocated with the
106  * GRALLOC_USAGE_HW_FB usage flag.
107  * buffer must be the same width and height as the display and must NOT
108  * be locked.
109  *
110  * The buffer is shown during the next VSYNC.
111  *
112  * If the same buffer is posted again (possibly after some other buffer),
113  * post() will block until the the first post is completed.
114  *
115  * Internally, post() is expected to lock the buffer so that a
116  * subsequent call to gralloc_module_t::(*lock)() with USAGE_RENDER or
117  * USAGE_*_WRITE will block until it is safe; that is typically once this
118  * buffer is shown and another buffer has been posted.
119  *
120  * Returns 0 on success or -errno on error.
121  */
122  int (*post)(struct framebuffer_device_t* dev, buffer_handle_t buffer);
123 
124 
125  /*
126  * The (*compositionComplete)() method must be called after the
127  * compositor has finished issuing GL commands for client buffers.
128  */
129 
131 
132  /*
133  * This hook is OPTIONAL.
134  *
135  * If non NULL it will be caused by SurfaceFlinger on dumpsys
136  */
137  void (*dump)(struct framebuffer_device_t* dev, char *buff, int buff_len);
138 
139  /*
140  * (*enableScreen)() is used to either blank (enable=0) or
141  * unblank (enable=1) the screen this framebuffer is attached to.
142  *
143  * Returns 0 on success or -errno on error.
144  */
145  int (*enableScreen)(struct framebuffer_device_t* dev, int enable);
146 
147  void* reserved_proc[6];
148 
150 
151 
152 /** convenience API for opening and closing a supported device */
153 
154 static inline int framebuffer_open(const struct hw_module_t* module,
155  struct framebuffer_device_t** device) {
156  return module->methods->open(module,
157  GRALLOC_HARDWARE_FB0, (struct hw_device_t**)device);
158 }
159 
160 static inline int framebuffer_close(struct framebuffer_device_t* device) {
161  return device->common.close(&device->common);
162 }
163 
164 
165 __END_DECLS
166 
167 #endif // ANDROID_FB_INTERFACE_H