1 /* 2 * Copyright (C) 2016 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_MMAP_STREAM_INTERFACE_H 18 #define ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 19 20 #include <system/audio.h> 21 #include <media/AudioClient.h> 22 #include <utils/Errors.h> 23 #include <utils/RefBase.h> 24 25 #include <time.h> 26 27 namespace android { 28 29 class MmapStreamCallback; 30 31 class MmapStreamInterface : public virtual RefBase 32 { 33 public: 34 35 /** 36 * Values for direction argument passed to openMmapStream() 37 */ 38 typedef enum { 39 DIRECTION_OUTPUT = 0, /**< open a playback mmap stream */ 40 DIRECTION_INPUT, /**< open a capture mmap stream */ 41 } stream_direction_t; 42 43 /** 44 * Open a playback or capture stream in MMAP mode at the audio HAL. 45 * 46 * \note This method is implemented by AudioFlinger 47 * 48 * \param[in] direction open a playback or capture stream. 49 * \param[in] attr audio attributes defining the main use case for this stream 50 * \param[in,out] config audio parameters (sampling rate, format ...) for the stream. 51 * Requested parameters as input, 52 * Actual parameters as output 53 * \param[in] client a AudioClient struct describing the first client using this stream. 54 * \param[in,out] deviceId audio device the stream should preferably be routed to/from 55 * Requested as input, 56 * Actual as output 57 * \param[in,out] sessionId audio sessionId for the stream 58 * Requested as input, may be AUDIO_SESSION_ALLOCATE 59 * Actual as output 60 * \param[in] callback the MmapStreamCallback interface used by AudioFlinger to notify 61 * condition changes affecting the stream operation 62 * \param[out] interface the MmapStreamInterface interface controlling the created stream 63 * \param[out] same unique handle as the one used for the first client stream started. 64 * \return OK if the stream was successfully created. 65 * NO_INIT if AudioFlinger is not properly initialized 66 * BAD_VALUE if the stream cannot be opened because of invalid arguments 67 * INVALID_OPERATION if the stream cannot be opened because of platform limitations 68 */ 69 static status_t openMmapStream(stream_direction_t direction, 70 const audio_attributes_t *attr, 71 audio_config_base_t *config, 72 const AudioClient& client, 73 audio_port_handle_t *deviceId, 74 audio_session_t *sessionId, 75 const sp<MmapStreamCallback>& callback, 76 sp<MmapStreamInterface>& interface, 77 audio_port_handle_t *handle); 78 79 /** 80 * Retrieve information on the mmap buffer used for audio samples transfer. 81 * Must be called before any other method after opening the stream or entering standby. 82 * 83 * \param[in] min_size_frames minimum buffer size requested. The actual buffer 84 * size returned in struct audio_mmap_buffer_info can be larger. 85 * \param[out] info address at which the mmap buffer information should be returned. 86 * 87 * \return OK if the buffer was allocated. 88 * NO_INIT in case of initialization error 89 * BAD_VALUE if the requested buffer size is too large 90 * INVALID_OPERATION if called out of sequence (e.g. buffer already allocated) 91 */ 92 virtual status_t createMmapBuffer(int32_t minSizeFrames, 93 struct audio_mmap_buffer_info *info) = 0; 94 95 /** 96 * Read current read/write position in the mmap buffer with associated time stamp. 97 * 98 * \param[out] position address at which the mmap read/write position should be returned. 99 * 100 * \return OK if the position is successfully returned. 101 * NO_INIT in case of initialization error 102 * NOT_ENOUGH_DATA if the position cannot be retrieved 103 * INVALID_OPERATION if called before createMmapBuffer() 104 */ 105 virtual status_t getMmapPosition(struct audio_mmap_position *position) = 0; 106 107 /** 108 * Get a recent count of the number of audio frames presented/received to/from an 109 * external observer. 110 * 111 * \param[out] position count of presented audio frames 112 * \param[out] timeNanos associated clock time 113 * 114 * \return OK if the external position is set correctly. 115 * NO_INIT in case of initialization error 116 * INVALID_OPERATION if the interface is not implemented 117 */ 118 virtual status_t getExternalPosition(uint64_t* position, int64_t* timeNanos) = 0; 119 120 /** 121 * Start a stream operating in mmap mode. 122 * createMmapBuffer() must be called before calling start() 123 * 124 * \param[in] client a AudioClient struct describing the client starting on this stream. 125 * \param[in] attr audio attributes provided by the client. 126 * \param[out] handle unique handle for this instance. Used with stop(). 127 * \return OK in case of success. 128 * NO_INIT in case of initialization error 129 * INVALID_OPERATION if called out of sequence 130 */ 131 virtual status_t start(const AudioClient& client, 132 const audio_attributes_t *attr, 133 audio_port_handle_t *handle) = 0; 134 135 /** 136 * Stop a stream operating in mmap mode. 137 * Must be called after start() 138 * 139 * \param[in] handle unique handle allocated by start(). 140 * \return OK in case of success. 141 * NO_INIT in case of initialization error 142 * INVALID_OPERATION if called out of sequence 143 */ 144 virtual status_t stop(audio_port_handle_t handle) = 0; 145 146 /** 147 * Put a stream operating in mmap mode into standby. 148 * Must be called after createMmapBuffer(). Cannot be called if any client is active. 149 * It is recommended to place a mmap stream into standby as often as possible when no client is 150 * active to save power. 151 * 152 * \return OK in case of success. 153 * NO_INIT in case of initialization error 154 * INVALID_OPERATION if called out of sequence 155 */ 156 virtual status_t standby() = 0; 157 158 /** 159 * Report when data being written to a playback buffer. Currently, this is used by mmap 160 * playback thread for sound dose computation. 161 * 162 * \param[in] buffer a pointer to the audio data 163 * \param[in] frameCount the number of frames written by the CPU 164 * \return OK in case of success. 165 * NO_INIT in case of initialization error 166 * INVALID_OPERATION in case of wrong thread type 167 */ 168 virtual status_t reportData(const void* buffer, size_t frameCount) = 0; 169 170 protected: 171 // Subclasses can not be constructed directly by clients. MmapStreamInterface()172 MmapStreamInterface() {} 173 174 // The destructor automatically closes the stream. ~MmapStreamInterface()175 virtual ~MmapStreamInterface() {} 176 }; 177 178 } // namespace android 179 180 #endif // ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 181