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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 
25 namespace 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 ~
59 struct 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.
88 private:
89                 uint32_t    mVolumeLR;
90 public:
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                 uint8_t     mName;           // normal tracks: track name, fast tracks: track index
101 
102                 // used by client only
103                 uint16_t    bufferTimeoutMs; // Maximum cumulated timeout before restarting audioflinger
104 
105                 uint16_t    waitTimeMs;      // Cumulated wait time, used by client only
106 private:
107                 // client write-only, server read-only
108                 uint16_t    mSendLevel;      // Fixed point U4.12 so 0x1000 means 1.0
109 public:
110     volatile    int32_t     flags;
111 
112                 // Cache line boundary (32 bytes)
113 
114                 // Since the control block is always located in shared memory, this constructor
115                 // is only used for placement new().  It is never used for regular new() or stack.
116                             audio_track_cblk_t();
117                 uint32_t    stepUser(uint32_t frameCount);      // called by client only, where
118                 // client includes regular AudioTrack and AudioFlinger::PlaybackThread::OutputTrack
119                 bool        stepServer(uint32_t frameCount);    // called by server only
120                 void*       buffer(uint32_t offset) const;
121                 uint32_t    framesAvailable();
122                 uint32_t    framesAvailable_l();
123                 uint32_t    framesReady();                      // called by server only
124                 bool        tryLock();
125 
126                 // No barriers on the following operations, so the ordering of loads/stores
127                 // with respect to other parameters is UNPREDICTABLE. That's considered safe.
128 
129                 // for AudioTrack client only, caller must limit to 0.0 <= sendLevel <= 1.0
setSendLevelaudio_track_cblk_t130                 void        setSendLevel(float sendLevel) {
131                     mSendLevel = uint16_t(sendLevel * 0x1000);
132                 }
133 
134                 // for AudioFlinger only; the return value must be validated by the caller
getSendLevel_U4_12audio_track_cblk_t135                 uint16_t    getSendLevel_U4_12() const {
136                     return mSendLevel;
137                 }
138 
139                 // for AudioTrack client only, caller must limit to 0 <= volumeLR <= 0x10001000
setVolumeLRaudio_track_cblk_t140                 void        setVolumeLR(uint32_t volumeLR) {
141                     mVolumeLR = volumeLR;
142                 }
143 
144                 // for AudioFlinger only; the return value must be validated by the caller
getVolumeLRaudio_track_cblk_t145                 uint32_t    getVolumeLR() const {
146                     return mVolumeLR;
147                 }
148 
149 };
150 
151 
152 // ----------------------------------------------------------------------------
153 
154 }; // namespace android
155 
156 #endif // ANDROID_AUDIO_TRACK_SHARED_H
157