AudioTrackShared.h revision 22eb4e239fbe9103568147d566d7482e480350b8 
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
35#define CBLK_UNDERRUN   0x01 // set: underrun (out) or overrrun (in), clear: no underrun or overrun
36#define CBLK_FORCEREADY 0x02 // set: track is considered ready immediately by AudioFlinger,
37                             // clear: track is ready when buffer full
38#define CBLK_INVALID    0x04 // track buffer invalidated by AudioFlinger, need to re-create
39#define CBLK_DISABLED   0x08 // track disabled by AudioFlinger due to underrun, need to re-start
40
41// Important: do not add any virtual methods, including ~
42struct audio_track_cblk_t
43{
44
45    // The data members are grouped so that members accessed frequently and in the same context
46    // are in the same line of data cache.
47                Mutex       lock;           // sizeof(int)
48                Condition   cv;             // sizeof(int)
49
50                // next 4 are offsets within "buffers"
51    volatile    uint32_t    user;
52    volatile    uint32_t    server;
53                uint32_t    userBase;
54                uint32_t    serverBase;
55
56                int         mPad1;          // unused, but preserves cache line alignment
57
58                uint32_t    frameCount;
59
60                // Cache line boundary (32 bytes)
61
62                uint32_t    loopStart;
63                uint32_t    loopEnd;        // read-only for server, read/write for client
64                int         loopCount;      // read/write for client
65
66                // Channel volumes are fixed point U4.12, so 0x1000 means 1.0.
67                // Left channel is in [0:15], right channel is in [16:31].
68                // Always read and write the combined pair atomically.
69                // For AudioTrack only, not used by AudioRecord.
70private:
71                uint32_t    mVolumeLR;
72public:
73
74                uint32_t    sampleRate;
75
76                uint8_t     mPad2;           // unused
77
78                // read-only for client, server writes once at initialization and is then read-only
79                uint8_t     mName;           // normal tracks: track name, fast tracks: track index
80
81                // used by client only
82                uint16_t    bufferTimeoutMs; // Maximum cumulated timeout before restarting
83                                             // audioflinger
84
85                uint16_t    waitTimeMs;      // Cumulated wait time, used by client only
86private:
87                // client write-only, server read-only
88                uint16_t    mSendLevel;      // Fixed point U4.12 so 0x1000 means 1.0
89public:
90    volatile    int32_t     flags;
91
92                // Cache line boundary (32 bytes)
93
94                // Since the control block is always located in shared memory, this constructor
95                // is only used for placement new().  It is never used for regular new() or stack.
96                            audio_track_cblk_t();
97
98                // called by client only, where client includes regular
99                // AudioTrack and AudioFlinger::PlaybackThread::OutputTrack
100                uint32_t    stepUserIn(uint32_t frameCount) { return stepUser(frameCount, false); }
101                uint32_t    stepUserOut(uint32_t frameCount) { return stepUser(frameCount, true); }
102
103                bool        stepServer(uint32_t frameCount, bool isOut);
104
105                // if there is a shared buffer, "buffers" is the value of pointer() for the shared
106                // buffer, otherwise "buffers" points immediately after the control block
107                void*       buffer(void *buffers, uint32_t frameSize, uint32_t offset) const;
108
109                uint32_t    framesAvailableIn() { return framesAvailable(false); }
110                uint32_t    framesAvailableOut() { return framesAvailable(true); }
111                uint32_t    framesAvailableIn_l() { return framesAvailable_l(false); }
112                uint32_t    framesAvailableOut_l() { return framesAvailable_l(true); }
113                uint32_t    framesReadyIn() { return framesReady(false); }
114                uint32_t    framesReadyOut() { return framesReady(true); }
115
116                bool        tryLock();
117
118                // No barriers on the following operations, so the ordering of loads/stores
119                // with respect to other parameters is UNPREDICTABLE. That's considered safe.
120
121                // for AudioTrack client only, caller must limit to 0.0 <= sendLevel <= 1.0
122                void        setSendLevel(float sendLevel) {
123                    mSendLevel = uint16_t(sendLevel * 0x1000);
124                }
125
126                // for AudioFlinger only; the return value must be validated by the caller
127                uint16_t    getSendLevel_U4_12() const {
128                    return mSendLevel;
129                }
130
131                // for AudioTrack client only, caller must limit to 0 <= volumeLR <= 0x10001000
132                void        setVolumeLR(uint32_t volumeLR) {
133                    mVolumeLR = volumeLR;
134                }
135
136                // for AudioFlinger only; the return value must be validated by the caller
137                uint32_t    getVolumeLR() const {
138                    return mVolumeLR;
139                }
140
141private:
142                // isOut == true means AudioTrack, isOut == false means AudioRecord
143                uint32_t    stepUser(uint32_t frameCount, bool isOut);
144                uint32_t    framesAvailable(bool isOut);
145                uint32_t    framesAvailable_l(bool isOut);
146                uint32_t    framesReady(bool isOut);
147};
148
149
150// ----------------------------------------------------------------------------
151
152}; // namespace android
153
154#endif // ANDROID_AUDIO_TRACK_SHARED_H
155