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 <media/AudioContainers.h> 23 #include <utils/Errors.h> 24 #include <utils/RefBase.h> 25 26 #include <time.h> 27 28 namespace android { 29 30 class MmapStreamCallback; 31 32 class MmapStreamInterface : public virtual RefBase 33 { 34 public: 35 36 /** 37 * Values for direction argument passed to openMmapStream() 38 */ 39 typedef enum { 40 DIRECTION_OUTPUT = 0, /**< open a playback mmap stream */ 41 DIRECTION_INPUT, /**< open a capture mmap stream */ 42 } stream_direction_t; 43 44 /** 45 * Open a playback or capture stream in MMAP mode at the audio HAL. 46 * 47 * \note This method is implemented by AudioFlinger 48 * 49 * \param[in] direction open a playback or capture stream. 50 * \param[in] attr audio attributes defining the main use case for this stream 51 * \param[in,out] config audio parameters (sampling rate, format ...) for the stream. 52 * Requested parameters as input, 53 * Actual parameters as output 54 * \param[in] client a AudioClient struct describing the first client using this stream. 55 * \param[in,out] deviceIds audio devices the stream should preferably be routed to/from. 56 * Leave empty if there are no preferred devices. 57 * Requested as input, 58 * Actual as output 59 * \param[in,out] sessionId audio sessionId for the stream 60 * Requested as input, may be AUDIO_SESSION_ALLOCATE 61 * Actual as output 62 * \param[in] callback the MmapStreamCallback interface used by AudioFlinger to notify 63 * condition changes affecting the stream operation 64 * \param[out] interface the MmapStreamInterface interface controlling the created stream 65 * \param[out] same unique handle as the one used for the first client stream started. 66 * \return OK if the stream was successfully created. 67 * NO_INIT if AudioFlinger is not properly initialized 68 * BAD_VALUE if the stream cannot be opened because of invalid arguments 69 * INVALID_OPERATION if the stream cannot be opened because of platform limitations 70 */ 71 static status_t openMmapStream(stream_direction_t direction, 72 const audio_attributes_t *attr, 73 audio_config_base_t *config, 74 const AudioClient& client, 75 DeviceIdVector *deviceIds, 76 audio_session_t *sessionId, 77 const sp<MmapStreamCallback>& callback, 78 sp<MmapStreamInterface>& interface, 79 audio_port_handle_t *handle); 80 81 /** 82 * Retrieve information on the mmap buffer used for audio samples transfer. 83 * Must be called before any other method after opening the stream or entering standby. 84 * 85 * \param[in] min_size_frames minimum buffer size requested. The actual buffer 86 * size returned in struct audio_mmap_buffer_info can be larger. 87 * \param[out] info address at which the mmap buffer information should be returned. 88 * 89 * \return OK if the buffer was allocated. 90 * NO_INIT in case of initialization error 91 * BAD_VALUE if the requested buffer size is too large 92 * INVALID_OPERATION if called out of sequence (e.g. buffer already allocated) 93 */ 94 virtual status_t createMmapBuffer(int32_t minSizeFrames, 95 struct audio_mmap_buffer_info *info) = 0; 96 97 /** 98 * Read current read/write position in the mmap buffer with associated time stamp. 99 * 100 * \param[out] position address at which the mmap read/write position should be returned. 101 * 102 * \return OK if the position is successfully returned. 103 * NO_INIT in case of initialization error 104 * NOT_ENOUGH_DATA if the position cannot be retrieved 105 * INVALID_OPERATION if called before createMmapBuffer() 106 */ 107 virtual status_t getMmapPosition(struct audio_mmap_position *position) = 0; 108 109 /** 110 * Get a recent count of the number of audio frames presented/received to/from an 111 * external observer. 112 * 113 * \param[out] position count of presented audio frames 114 * \param[out] timeNanos associated clock time 115 * 116 * \return OK if the external position is set correctly. 117 * NO_INIT in case of initialization error 118 * INVALID_OPERATION if the interface is not implemented 119 */ 120 virtual status_t getExternalPosition(uint64_t* position, int64_t* timeNanos) = 0; 121 122 /** 123 * Start a stream operating in mmap mode. 124 * createMmapBuffer() must be called before calling start() 125 * 126 * \param[in] client a AudioClient struct describing the client starting on this stream. 127 * \param[in] attr audio attributes provided by the client. 128 * \param[out] handle unique handle for this instance. Used with stop(). 129 * \return OK in case of success. 130 * NO_INIT in case of initialization error 131 * INVALID_OPERATION if called out of sequence 132 */ 133 virtual status_t start(const AudioClient& client, 134 const audio_attributes_t *attr, 135 audio_port_handle_t *handle) = 0; 136 137 /** 138 * Stop a stream operating in mmap mode. 139 * Must be called after start() 140 * 141 * \param[in] handle unique handle allocated by start(). 142 * \return OK in case of success. 143 * NO_INIT in case of initialization error 144 * INVALID_OPERATION if called out of sequence 145 */ 146 virtual status_t stop(audio_port_handle_t handle) = 0; 147 148 /** 149 * Put a stream operating in mmap mode into standby. 150 * Must be called after createMmapBuffer(). Cannot be called if any client is active. 151 * It is recommended to place a mmap stream into standby as often as possible when no client is 152 * active to save power. 153 * 154 * \return OK in case of success. 155 * NO_INIT in case of initialization error 156 * INVALID_OPERATION if called out of sequence 157 */ 158 virtual status_t standby() = 0; 159 160 /** 161 * Report when data being written to a playback buffer. Currently, this is used by mmap 162 * playback thread for sound dose computation. 163 * 164 * \param[in] buffer a pointer to the audio data 165 * \param[in] frameCount the number of frames written by the CPU 166 * \return OK in case of success. 167 * NO_INIT in case of initialization error 168 * INVALID_OPERATION in case of wrong thread type 169 */ 170 virtual status_t reportData(const void* buffer, size_t frameCount) = 0; 171 172 protected: 173 // Subclasses can not be constructed directly by clients. MmapStreamInterface()174 MmapStreamInterface() {} 175 176 // The destructor automatically closes the stream. ~MmapStreamInterface()177 virtual ~MmapStreamInterface() {} 178 }; 179 180 } // namespace android 181 182 #endif // ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 183