Android Hardware Abstraction Layer
gralloc.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_GRALLOC_INTERFACE_H
19 #define ANDROID_GRALLOC_INTERFACE_H
20 
21 #include <system/window.h>
22 #include <system/graphics.h>
23 #include <hardware/hardware.h>
24 
25 #include <stdint.h>
26 #include <sys/cdefs.h>
27 #include <sys/types.h>
28 
29 #include <cutils/native_handle.h>
30 
31 #include <hardware/hardware.h>
32 #include <hardware/fb.h>
33 
34 __BEGIN_DECLS
35 
36 /**
37  * Module versioning information for the Gralloc hardware module, based on
38  * gralloc_module_t.common.module_api_version.
39  *
40  * Version History:
41  *
42  * GRALLOC_MODULE_API_VERSION_0_1:
43  * Initial Gralloc hardware module API.
44  *
45  * GRALLOC_MODULE_API_VERSION_0_2:
46  * Add support for flexible YCbCr format with (*lock_ycbcr)() method.
47  */
48 
49 #define GRALLOC_MODULE_API_VERSION_0_1 HARDWARE_MODULE_API_VERSION(0, 1)
50 #define GRALLOC_MODULE_API_VERSION_0_2 HARDWARE_MODULE_API_VERSION(0, 2)
51 
52 #define GRALLOC_DEVICE_API_VERSION_0_1 HARDWARE_DEVICE_API_VERSION(0, 1)
53 
54 /**
55  * The id of this module
56  */
57 #define GRALLOC_HARDWARE_MODULE_ID "gralloc"
58 
59 /**
60  * Name of the graphics device to open
61  */
62 
63 #define GRALLOC_HARDWARE_GPU0 "gpu0"
64 
65 enum {
66  /* buffer is never read in software */
68  /* buffer is rarely read in software */
70  /* buffer is often read in software */
72  /* mask for the software read values */
74 
75  /* buffer is never written in software */
77  /* buffer is rarely written in software */
79  /* buffer is often written in software */
81  /* mask for the software write values */
83 
84  /* buffer will be used as an OpenGL ES texture */
86  /* buffer will be used as an OpenGL ES render target */
88  /* buffer will be used by the 2D hardware blitter */
89  GRALLOC_USAGE_HW_2D = 0x00000400,
90  /* buffer will be used by the HWComposer HAL module */
92  /* buffer will be used with the framebuffer device */
93  GRALLOC_USAGE_HW_FB = 0x00001000,
94  /* buffer will be used with the HW video encoder */
96  /* buffer will be written by the HW camera pipeline */
98  /* buffer will be read by the HW camera pipeline */
100  /* buffer will be used as part of zero-shutter-lag queue */
102  /* mask for the camera access values */
104  /* mask for the software usage bit-mask */
105  GRALLOC_USAGE_HW_MASK = 0x00071F00,
106 
107  /* buffer will be used as a RenderScript Allocation */
109 
110  /* buffer should be displayed full-screen on an external display when
111  * possible
112  */
114 
115  /* Must have a hardware-protected path to external display sink for
116  * this buffer. If a hardware-protected path is not available, then
117  * either don't composite only this buffer (preferred) to the
118  * external sink, or (less desirable) do not route the entire
119  * composition to the external sink.
120  */
122 
123  /* implementation-specific private usage flags */
129 };
130 
131 /*****************************************************************************/
132 
133 /**
134  * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
135  * and the fields of this data structure must begin with hw_module_t
136  * followed by module specific information.
137  */
138 typedef struct gralloc_module_t {
140 
141  /*
142  * (*registerBuffer)() must be called before a buffer_handle_t that has not
143  * been created with (*alloc_device_t::alloc)() can be used.
144  *
145  * This is intended to be used with buffer_handle_t's that have been
146  * received in this process through IPC.
147  *
148  * This function checks that the handle is indeed a valid one and prepares
149  * it for use with (*lock)() and (*unlock)().
150  *
151  * It is not necessary to call (*registerBuffer)() on a handle created
152  * with (*alloc_device_t::alloc)().
153  *
154  * returns an error if this buffer_handle_t is not valid.
155  */
156  int (*registerBuffer)(struct gralloc_module_t const* module,
157  buffer_handle_t handle);
158 
159  /*
160  * (*unregisterBuffer)() is called once this handle is no longer needed in
161  * this process. After this call, it is an error to call (*lock)(),
162  * (*unlock)(), or (*registerBuffer)().
163  *
164  * This function doesn't close or free the handle itself; this is done
165  * by other means, usually through libcutils's native_handle_close() and
166  * native_handle_free().
167  *
168  * It is an error to call (*unregisterBuffer)() on a buffer that wasn't
169  * explicitly registered first.
170  */
171  int (*unregisterBuffer)(struct gralloc_module_t const* module,
172  buffer_handle_t handle);
173 
174  /*
175  * The (*lock)() method is called before a buffer is accessed for the
176  * specified usage. This call may block, for instance if the h/w needs
177  * to finish rendering or if CPU caches need to be synchronized.
178  *
179  * The caller promises to modify only pixels in the area specified
180  * by (l,t,w,h).
181  *
182  * The content of the buffer outside of the specified area is NOT modified
183  * by this call.
184  *
185  * If usage specifies GRALLOC_USAGE_SW_*, vaddr is filled with the address
186  * of the buffer in virtual memory.
187  *
188  * Note calling (*lock)() on HAL_PIXEL_FORMAT_YCbCr_*_888 buffers will fail
189  * and return -EINVAL. These buffers must be locked with (*lock_ycbcr)()
190  * instead.
191  *
192  * THREADING CONSIDERATIONS:
193  *
194  * It is legal for several different threads to lock a buffer from
195  * read access, none of the threads are blocked.
196  *
197  * However, locking a buffer simultaneously for write or read/write is
198  * undefined, but:
199  * - shall not result in termination of the process
200  * - shall not block the caller
201  * It is acceptable to return an error or to leave the buffer's content
202  * into an indeterminate state.
203  *
204  * If the buffer was created with a usage mask incompatible with the
205  * requested usage flags here, -EINVAL is returned.
206  *
207  */
208 
209  int (*lock)(struct gralloc_module_t const* module,
210  buffer_handle_t handle, int usage,
211  int l, int t, int w, int h,
212  void** vaddr);
213 
214 
215  /*
216  * The (*unlock)() method must be called after all changes to the buffer
217  * are completed.
218  */
219 
220  int (*unlock)(struct gralloc_module_t const* module,
221  buffer_handle_t handle);
222 
223 
224  /* reserved for future use */
225  int (*perform)(struct gralloc_module_t const* module,
226  int operation, ... );
227 
228  /*
229  * The (*lock_ycbcr)() method is like the (*lock)() method, with the
230  * difference that it fills a struct ycbcr with a description of the buffer
231  * layout, and zeroes out the reserved fields.
232  *
233  * This will only work on buffers with HAL_PIXEL_FORMAT_YCbCr_*_888, and
234  * will return -EINVAL on any other buffer formats.
235  *
236  * Added in GRALLOC_MODULE_API_VERSION_0_2.
237  */
238 
239  int (*lock_ycbcr)(struct gralloc_module_t const* module,
240  buffer_handle_t handle, int usage,
241  int l, int t, int w, int h,
242  struct android_ycbcr *ycbcr);
243 
244  /* reserved for future use */
245  void* reserved_proc[6];
247 
248 /*****************************************************************************/
249 
250 /**
251  * Every device data structure must begin with hw_device_t
252  * followed by module specific public methods and attributes.
253  */
254 
255 typedef struct alloc_device_t {
257 
258  /*
259  * (*alloc)() Allocates a buffer in graphic memory with the requested
260  * parameters and returns a buffer_handle_t and the stride in pixels to
261  * allow the implementation to satisfy hardware constraints on the width
262  * of a pixmap (eg: it may have to be multiple of 8 pixels).
263  * The CALLER TAKES OWNERSHIP of the buffer_handle_t.
264  *
265  * If format is HAL_PIXEL_FORMAT_YCbCr_420_888, the returned stride must be
266  * 0, since the actual strides are available from the android_ycbcr
267  * structure.
268  *
269  * Returns 0 on success or -errno on error.
270  */
271 
272  int (*alloc)(struct alloc_device_t* dev,
273  int w, int h, int format, int usage,
274  buffer_handle_t* handle, int* stride);
275 
276  /*
277  * (*free)() Frees a previously allocated buffer.
278  * Behavior is undefined if the buffer is still mapped in any process,
279  * but shall not result in termination of the program or security breaches
280  * (allowing a process to get access to another process' buffers).
281  * THIS FUNCTION TAKES OWNERSHIP of the buffer_handle_t which becomes
282  * invalid after the call.
283  *
284  * Returns 0 on success or -errno on error.
285  */
286  int (*free)(struct alloc_device_t* dev,
287  buffer_handle_t handle);
288 
289  /* This hook is OPTIONAL.
290  *
291  * If non NULL it will be caused by SurfaceFlinger on dumpsys
292  */
293  void (*dump)(struct alloc_device_t *dev, char *buff, int buff_len);
294 
295  void* reserved_proc[7];
297 
298 
299 /** convenience API for opening and closing a supported device */
300 
301 static inline int gralloc_open(const struct hw_module_t* module,
302  struct alloc_device_t** device) {
303  return module->methods->open(module,
304  GRALLOC_HARDWARE_GPU0, (struct hw_device_t**)device);
305 }
306 
307 static inline int gralloc_close(struct alloc_device_t* device) {
308  return device->common.close(&device->common);
309 }
310 
311 __END_DECLS
312 
313 #endif // ANDROID_GRALLOC_INTERFACE_H