AudioTrackShared.h revision 2f6226ad7a3fa81dc102001fbc1d1288e55a0947 
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
31                                        // init time
32#define MAX_RUN_TIMEOUT_MS      1000
33#define WAIT_PERIOD_MS          10
34// AudioTrack no longer uses this, it is for AudioRecord only:
35#define RESTORE_TIMEOUT_MS      5000    // Maximum waiting time for a track to be restored
36
37#define CBLK_UNDERRUN   0x01 // set: underrun (out) or overrrun (in), clear: no underrun or overrun
38#define CBLK_FORCEREADY 0x02 // set: track is considered ready immediately by AudioFlinger,
39                             // clear: track is ready when buffer full
40#define CBLK_INVALID    0x04 // track buffer invalidated by AudioFlinger, need to re-create
41#define CBLK_DISABLED   0x08 // track disabled by AudioFlinger due to underrun, need to re-start
42// AudioTrack no longer uses these, they are for AudioRecord only:
43#define CBLK_RESTORING  0x10 // track is being restored after invalidation by AudioFlinger
44#define CBLK_RESTORED   0x20 // track has been restored after invalidation by AudioFlinger
45
46// Important: do not add any virtual methods, including ~
47struct audio_track_cblk_t
48{
49
50    // The data members are grouped so that members accessed frequently and in the same context
51    // are in the same line of data cache.
52                Mutex       lock;           // sizeof(int)
53                Condition   cv;             // sizeof(int)
54
55                // next 4 are offsets within "buffers"
56    volatile    uint32_t    user;
57    volatile    uint32_t    server;
58                uint32_t    userBase;
59                uint32_t    serverBase;
60
61                int         mPad1;          // unused, but preserves cache line alignment
62                uint32_t    frameCount;
63
64                // Cache line boundary
65
66                uint32_t    loopStart;
67                uint32_t    loopEnd;        // read-only for server, read/write for client
68                int         loopCount;      // read/write for client
69
70                // Channel volumes are fixed point U4.12, so 0x1000 means 1.0.
71                // Left channel is in [0:15], right channel is in [16:31].
72                // Always read and write the combined pair atomically.
73                // For AudioTrack only, not used by AudioRecord.
74private:
75                uint32_t    mVolumeLR;
76public:
77
78                uint32_t    sampleRate;
79
80                // NOTE: audio_track_cblk_t::frameSize is not equal to AudioTrack::frameSize() for
81                // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
82                // 16 bit because data is converted to 16 bit before being stored in buffer
83
84                // read-only for client, server writes once at initialization and is then read-only
85                uint8_t     frameSize;       // would normally be size_t, but 8 bits is plenty
86                uint8_t     mName;           // normal tracks: track name, fast tracks: track index
87
88                // used by client only
89                uint16_t    bufferTimeoutMs; // Maximum cumulated timeout before restarting
90                                             // audioflinger
91
92                uint16_t    waitTimeMs;      // Cumulated wait time, used by client only
93private:
94                // client write-only, server read-only
95                uint16_t    mSendLevel;      // Fixed point U4.12 so 0x1000 means 1.0
96public:
97    volatile    int32_t     flags;
98
99                // Cache line boundary (32 bytes)
100
101                // Since the control block is always located in shared memory, this constructor
102                // is only used for placement new().  It is never used for regular new() or stack.
103                            audio_track_cblk_t();
104
105                // called by client only, where client includes regular
106                // AudioTrack and AudioFlinger::PlaybackThread::OutputTrack
107                uint32_t    stepUserIn(uint32_t frameCount) { return stepUser(frameCount, false); }
108                uint32_t    stepUserOut(uint32_t frameCount) { return stepUser(frameCount, true); }
109
110                bool        stepServer(uint32_t frameCount, bool isOut);
111
112                // if there is a shared buffer, "buffers" is the value of pointer() for the shared
113                // buffer, otherwise "buffers" points immediately after the control block
114                void*       buffer(void *buffers, uint32_t offset) const;
115
116                uint32_t    framesAvailableIn() { return framesAvailable(false); }
117                uint32_t    framesAvailableOut() { return framesAvailable(true); }
118                uint32_t    framesAvailableIn_l() { return framesAvailable_l(false); }
119                uint32_t    framesAvailableOut_l() { return framesAvailable_l(true); }
120                uint32_t    framesReadyIn() { return framesReady(false); }
121                uint32_t    framesReadyOut() { return framesReady(true); }
122
123                bool        tryLock();
124
125                // No barriers on the following operations, so the ordering of loads/stores
126                // with respect to other parameters is UNPREDICTABLE. That's considered safe.
127
128                // for AudioTrack client only, caller must limit to 0.0 <= sendLevel <= 1.0
129                void        setSendLevel(float sendLevel) {
130                    mSendLevel = uint16_t(sendLevel * 0x1000);
131                }
132
133                // for AudioFlinger only; the return value must be validated by the caller
134                uint16_t    getSendLevel_U4_12() const {
135                    return mSendLevel;
136                }
137
138                // for AudioTrack client only, caller must limit to 0 <= volumeLR <= 0x10001000
139                void        setVolumeLR(uint32_t volumeLR) {
140                    mVolumeLR = volumeLR;
141                }
142
143                // for AudioFlinger only; the return value must be validated by the caller
144                uint32_t    getVolumeLR() const {
145                    return mVolumeLR;
146                }
147
148private:
149                // isOut == true means AudioTrack, isOut == false means AudioRecord
150                uint32_t    stepUser(uint32_t frameCount, bool isOut);
151                uint32_t    framesAvailable(bool isOut);
152                uint32_t    framesAvailable_l(bool isOut);
153                uint32_t    framesReady(bool isOut);
154};
155
156
157// ----------------------------------------------------------------------------
158
159}; // namespace android
160
161#endif // ANDROID_AUDIO_TRACK_SHARED_H
162