gralloc.h revision 9d82c1a447a72a2c086b9cd34c5b73b163d7acbc 
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 <cutils/native_handle.h>
22
23#include <hardware/hardware.h>
24
25#include <stdint.h>
26#include <sys/cdefs.h>
27#include <sys/types.h>
28
29__BEGIN_DECLS
30
31/**
32 * The id of this module
33 */
34#define GRALLOC_HARDWARE_MODULE_ID "gralloc"
35
36/**
37 * Name of the graphics device to open
38 */
39
40#define GRALLOC_HARDWARE_FB0 "fb0"
41#define GRALLOC_HARDWARE_GPU0 "gpu0"
42
43enum {
44    /* buffer is never read in software */
45    GRALLOC_USAGE_SW_READ_NEVER   = 0x00000000,
46    /* buffer is rarely read in software */
47    GRALLOC_USAGE_SW_READ_RARELY  = 0x00000002,
48    /* buffer is often read in software */
49    GRALLOC_USAGE_SW_READ_OFTEN   = 0x00000003,
50    /* mask for the software read values */
51    GRALLOC_USAGE_SW_READ_MASK    = 0x0000000F,
52
53    /* buffer is never written in software */
54    GRALLOC_USAGE_SW_WRITE_NEVER  = 0x00000000,
55    /* buffer is never written in software */
56    GRALLOC_USAGE_SW_WRITE_RARELY = 0x00000020,
57    /* buffer is never written in software */
58    GRALLOC_USAGE_SW_WRITE_OFTEN  = 0x00000030,
59    /* mask for the software write values */
60    GRALLOC_USAGE_SW_WRITE_MASK   = 0x000000F0,
61
62    /* buffer will be used as an OpenGL ES texture */
63    GRALLOC_USAGE_HW_TEXTURE      = 0x00000100,
64    /* buffer will be used as an OpenGL ES render target */
65    GRALLOC_USAGE_HW_RENDER       = 0x00000200,
66    /* buffer will be used by the 2D hardware blitter */
67    GRALLOC_USAGE_HW_2D           = 0x00000C00,
68    /* buffer will be used with the framebuffer device */
69    GRALLOC_USAGE_HW_FB           = 0x00001000,
70    /* mask for the software usage bit-mask */
71    GRALLOC_USAGE_HW_MASK         = 0x00001F00,
72};
73
74/*****************************************************************************/
75
76typedef const native_handle* buffer_handle_t;
77
78/**
79 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
80 * and the fields of this data structure must begin with hw_module_t
81 * followed by module specific information.
82 */
83typedef struct gralloc_module_t {
84    struct hw_module_t common;
85
86
87    /*
88     * (*registerBuffer)() must be called before a buffer_handle_t that has not
89     * been created with (*alloc_device_t::alloc)() can be used.
90     *
91     * This is intended to be used with buffer_handle_t's that have been
92     * received in this process through IPC.
93     *
94     * This function checks that the handle is indeed a valid one and prepares
95     * it for use with (*lock)() and (*unlock)().
96     *
97     * It is not necessary to call (*registerBuffer)() on a handle created
98     * with (*alloc_device_t::alloc)().
99     *
100     * returns an error if this buffer_handle_t is not valid.
101     */
102    int (*registerBuffer)(struct gralloc_module_t const* module,
103            buffer_handle_t handle);
104
105    /*
106     * (*unregisterBuffer)() is called once this handle is no longer needed in
107     * this process. After this call, it is an error to call (*lock)(),
108     * (*unlock)(), or (*registerBuffer)().
109     *
110     * This function doesn't close or free the handle itself; this is done
111     * by other means, usually through libcutils's native_handle_close() and
112     * native_handle_free().
113     *
114     * It is an error to call (*unregisterBuffer)() on a buffer that wasn't
115     * explicitly registered first.
116     */
117    int (*unregisterBuffer)(struct gralloc_module_t const* module,
118            buffer_handle_t handle);
119
120    /*
121     * The (*lock)() method is called before a buffer is accessed for the
122     * specified usage. This call may block, for instance if the h/w needs
123     * to finish rendering or if CPU caches need to be synchronized.
124     *
125     * The caller promises to modify only pixels in the area specified
126     * by (l,t,w,h).
127     *
128     * The content of the buffer outside of the specified area is NOT modified
129     * by this call.
130     *
131     * If usage specifies GRALLOC_USAGE_SW_*, vaddr is filled with the address
132     * of the buffer in virtual memory.
133     *
134     * THREADING CONSIDERATIONS:
135     *
136     * It is legal for several different threads to lock a buffer from
137     * read access, none of the threads are blocked.
138     *
139     * However, locking a buffer simultaneously for write or read/write is
140     * undefined, but:
141     * - shall not result in termination of the process
142     * - shall not block the caller
143     * It is acceptable to return an error or to leave the buffer's content
144     * into an indeterminate state.
145     *
146     * If the buffer was created with a usage mask incompatible with the
147     * requested usage flags here, -EINVAL is returned.
148     *
149     */
150
151    int (*lock)(struct gralloc_module_t const* module,
152            buffer_handle_t handle, int usage,
153            int l, int t, int w, int h,
154            void** vaddr);
155
156
157    /*
158     * The (*unlock)() method must be called after all changes to the buffer
159     * are completed.
160     */
161
162    int (*unlock)(struct gralloc_module_t const* module,
163            buffer_handle_t handle);
164
165} gralloc_module_t;
166
167/*****************************************************************************/
168
169/**
170 * Every device data structure must begin with hw_device_t
171 * followed by module specific public methods and attributes.
172 */
173
174typedef struct alloc_device_t {
175    struct hw_device_t common;
176
177    /*
178     * (*alloc)() Allocates a buffer in graphic memory with the requested
179     * parameters and returns a buffer_handle_t and the stride in pixels to
180     * allow the implementation to satisfy hardware constraints on the width
181     * of a pixmap (eg: it may have to be multiple of 8 pixels).
182     * The CALLER TAKES OWNERSHIP of the buffer_handle_t.
183     *
184     * Returns 0 on success or -errno on error.
185     */
186
187    int (*alloc)(struct alloc_device_t* dev,
188            int w, int h, int format, int usage,
189            buffer_handle_t* handle, int* stride);
190
191    /*
192     * (*free)() Frees a previously allocated buffer.
193     * Behavior is undefined if the buffer is still mapped in any process,
194     * but shall not result in termination of the program or security breaches
195     * (allowing a process to get access to another process' buffers).
196     * THIS FUNCTION TAKES OWNERSHIP of the buffer_handle_t which becomes
197     * invalid after the call.
198     *
199     * Returns 0 on success or -errno on error.
200     */
201    int (*free)(struct alloc_device_t* dev,
202            buffer_handle_t handle);
203
204} alloc_device_t;
205
206
207typedef struct framebuffer_device_t {
208    struct hw_device_t common;
209
210    /* flags describing some attributes of the framebuffer */
211    const uint32_t  flags;
212
213    /* dimensions of the framebuffer in pixels */
214    const uint32_t  width;
215    const uint32_t  height;
216
217    /* frambuffer stride in pixels */
218    const int       stride;
219
220    /* framebuffer pixel format */
221    const int       format;
222
223    /* resolution of the framebuffer's display panel in pixel per inch*/
224    const float     xdpi;
225    const float     ydpi;
226
227    /* framebuffer's display panel refresh rate in frames per second */
228    const float     fps;
229
230    /* min swap interval supported by this framebuffer */
231    const int       minSwapInterval;
232
233    /* max swap interval supported by this framebuffer */
234    const int       maxSwapInterval;
235
236    int reserved[8];
237
238    /*
239     * requests a specific swap-interval (same definition than EGL)
240     *
241     * Returns 0 on success or -errno on error.
242     */
243    int (*setSwapInterval)(struct framebuffer_device_t* window,
244            int interval);
245
246    /*
247     * This hook is OPTIONAL.
248     *
249     * It is non NULL If the framebuffer driver supports "update-on-demand"
250     * and the given rectangle is the area of the screen that gets
251     * updated during (*post)().
252     *
253     * This is useful on devices that are able to DMA only a portion of
254     * the screen to the display panel, upon demand -- as opposed to
255     * constantly refreshing the panel 60 times per second, for instance.
256     *
257     * Only the area defined by this rectangle is guranteed to be valid, that
258     * is, the driver is not allowed to post anything outside of this
259     * rectangle.
260     *
261     * The rectangle evaluated during (*post)() and specifies which area
262     * of the buffer passed in (*post)() shall to be posted.
263     *
264     * return -EINVAL if width or height <=0, or if left or top < 0
265     */
266    int (*setUpdateRect)(struct framebuffer_device_t* window,
267            int left, int top, int width, int height);
268
269    /*
270     * Post <buffer> to the display (display it on the screen)
271     * The buffer must have been allocated with the
272     *   GRALLOC_USAGE_HW_FB usage flag.
273     * buffer must be the same width and height as the display and must NOT
274     * be locked.
275     *
276     * The buffer is shown during the next VSYNC.
277     *
278     * If the same buffer is posted again (possibly after some other buffer),
279     * post() will block until the the first post is completed.
280     *
281     * Internally, post() is expected to lock the buffer so that a
282     * subsequent call to gralloc_module_t::(*lock)() with USAGE_RENDER or
283     * USAGE_*_WRITE will block until it is safe; that is typically once this
284     * buffer is shown and another buffer has been posted.
285     *
286     * Returns 0 on success or -errno on error.
287     */
288    int (*post)(struct framebuffer_device_t* dev, buffer_handle_t buffer);
289
290    void* reserved_proc[8];
291
292} framebuffer_device_t;
293
294
295/** convenience API for opening and closing a supported device */
296
297static inline int gralloc_open(const struct hw_module_t* module,
298        struct alloc_device_t** device) {
299    return module->methods->open(module,
300            GRALLOC_HARDWARE_GPU0, (struct hw_device_t**)device);
301}
302
303static inline int gralloc_close(struct alloc_device_t* device) {
304    return device->common.close(&device->common);
305}
306
307
308static inline int framebuffer_open(const struct hw_module_t* module,
309        struct framebuffer_device_t** device) {
310    return module->methods->open(module,
311            GRALLOC_HARDWARE_FB0, (struct hw_device_t**)device);
312}
313
314static inline int framebuffer_close(struct framebuffer_device_t* device) {
315    return device->common.close(&device->common);
316}
317
318
319__END_DECLS
320
321#endif  // ANDROID_ALLOC_INTERFACE_H
322