AudioTrackShared.h revision 3acbd053c842e76e1a40fc8a0bf62de87eebf00f 
1/*
2 * Copyright (C) 2007 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#ifndef ANDROID_AUDIO_TRACK_SHARED_H
18#define ANDROID_AUDIO_TRACK_SHARED_H
19
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <utils/threads.h>
24
25namespace android {
26
27// ----------------------------------------------------------------------------
28
29// Maximum cumulated timeout milliseconds before restarting audioflinger thread
30#define MAX_STARTUP_TIMEOUT_MS  3000    // Longer timeout period at startup to cope with A2DP init time
31#define MAX_RUN_TIMEOUT_MS      1000
32#define WAIT_PERIOD_MS          10
33#define RESTORE_TIMEOUT_MS      5000    // Maximum waiting time for a track to be restored
34
35#define CBLK_UNDERRUN_MSK       0x0001
36#define CBLK_UNDERRUN_ON        0x0001  // underrun (out) or overrrun (in) indication
37#define CBLK_UNDERRUN_OFF       0x0000  // no underrun
38#define CBLK_DIRECTION_MSK      0x0002
39#define CBLK_DIRECTION_OUT      0x0002  // this cblk is for an AudioTrack
40#define CBLK_DIRECTION_IN       0x0000  // this cblk is for an AudioRecord
41#define CBLK_FORCEREADY_MSK     0x0004
42#define CBLK_FORCEREADY_ON      0x0004  // track is considered ready immediately by AudioFlinger
43#define CBLK_FORCEREADY_OFF     0x0000  // track is ready when buffer full
44#define CBLK_INVALID_MSK        0x0008
45#define CBLK_INVALID_ON         0x0008  // track buffer is invalidated by AudioFlinger:
46#define CBLK_INVALID_OFF        0x0000  // must be re-created
47#define CBLK_DISABLED_MSK       0x0010
48#define CBLK_DISABLED_ON        0x0010  // track disabled by AudioFlinger due to underrun:
49#define CBLK_DISABLED_OFF       0x0000  // must be re-started
50#define CBLK_RESTORING_MSK      0x0020
51#define CBLK_RESTORING_ON       0x0020  // track is being restored after invalidation
52#define CBLK_RESTORING_OFF      0x0000  // by AudioFlinger
53#define CBLK_RESTORED_MSK       0x0040
54#define CBLK_RESTORED_ON        0x0040  // track has been restored after invalidation
55#define CBLK_RESTORED_OFF       0x0040  // by AudioFlinger
56#define CBLK_FAST               0x0080  // AudioFlinger successfully created a fast track
57
58// Important: do not add any virtual methods, including ~
59struct audio_track_cblk_t
60{
61
62    // The data members are grouped so that members accessed frequently and in the same context
63    // are in the same line of data cache.
64                Mutex       lock;           // sizeof(int)
65                Condition   cv;             // sizeof(int)
66
67                // next 4 are offsets within "buffers"
68    volatile    uint32_t    user;
69    volatile    uint32_t    server;
70                uint32_t    userBase;
71                uint32_t    serverBase;
72
73                // if there is a shared buffer, "buffers" is the value of pointer() for the shared
74                // buffer, otherwise "buffers" points immediately after the control block
75                void*       buffers;
76                uint32_t    frameCount;
77
78                // Cache line boundary
79
80                uint32_t    loopStart;
81                uint32_t    loopEnd;        // read-only for server, read/write for client
82                int         loopCount;      // read/write for client
83
84                // Channel volumes are fixed point U4.12, so 0x1000 means 1.0.
85                // Left channel is in [0:15], right channel is in [16:31].
86                // Always read and write the combined pair atomically.
87                // For AudioTrack only, not used by AudioRecord.
88private:
89                uint32_t    mVolumeLR;
90public:
91
92                uint32_t    sampleRate;
93
94                // NOTE: audio_track_cblk_t::frameSize is not equal to AudioTrack::frameSize() for
95                // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
96                // 16 bit because data is converted to 16 bit before being stored in buffer
97
98                // read-only for client, server writes once at initialization and is then read-only
99                uint8_t     frameSize;       // would normally be size_t, but 8 bits is plenty
100
101                // never used
102                uint8_t     pad1;
103
104                // used by client only
105                uint16_t    bufferTimeoutMs; // Maximum cumulated timeout before restarting audioflinger
106
107                uint16_t    waitTimeMs;      // Cumulated wait time, used by client only
108private:
109                // client write-only, server read-only
110                uint16_t    mSendLevel;      // Fixed point U4.12 so 0x1000 means 1.0
111public:
112    volatile    int32_t     flags;
113
114                // Cache line boundary (32 bytes)
115
116                // Since the control block is always located in shared memory, this constructor
117                // is only used for placement new().  It is never used for regular new() or stack.
118                            audio_track_cblk_t();
119                uint32_t    stepUser(uint32_t frameCount);      // called by client only, where
120                // client includes regular AudioTrack and AudioFlinger::PlaybackThread::OutputTrack
121                bool        stepServer(uint32_t frameCount);    // called by server only
122                void*       buffer(uint32_t offset) const;
123                uint32_t    framesAvailable();
124                uint32_t    framesAvailable_l();
125                uint32_t    framesReady();                      // called by server only
126                bool        tryLock();
127
128                // No barriers on the following operations, so the ordering of loads/stores
129                // with respect to other parameters is UNPREDICTABLE. That's considered safe.
130
131                // for AudioTrack client only, caller must limit to 0.0 <= sendLevel <= 1.0
132                void        setSendLevel(float sendLevel) {
133                    mSendLevel = uint16_t(sendLevel * 0x1000);
134                }
135
136                // for AudioFlinger only; the return value must be validated by the caller
137                uint16_t    getSendLevel_U4_12() const {
138                    return mSendLevel;
139                }
140
141                // for AudioTrack client only, caller must limit to 0 <= volumeLR <= 0x10001000
142                void        setVolumeLR(uint32_t volumeLR) {
143                    mVolumeLR = volumeLR;
144                }
145
146                // for AudioFlinger only; the return value must be validated by the caller
147                uint32_t    getVolumeLR() const {
148                    return mVolumeLR;
149                }
150
151};
152
153
154// ----------------------------------------------------------------------------
155
156}; // namespace android
157
158#endif // ANDROID_AUDIO_TRACK_SHARED_H
159