audio.h revision 431fc78c112646f43d6d6f51b06d45d248d2f317 
1/*
2 * Copyright (C) 2011 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
18#ifndef ANDROID_AUDIO_HAL_INTERFACE_H
19#define ANDROID_AUDIO_HAL_INTERFACE_H
20
21#include <stdint.h>
22#include <strings.h>
23#include <sys/cdefs.h>
24#include <sys/types.h>
25
26#include <cutils/bitops.h>
27
28#include <hardware/hardware.h>
29#include <system/audio.h>
30#include <hardware/audio_effect.h>
31
32__BEGIN_DECLS
33
34/**
35 * The id of this module
36 */
37#define AUDIO_HARDWARE_MODULE_ID "audio"
38
39/**
40 * Name of the audio devices to open
41 */
42#define AUDIO_HARDWARE_INTERFACE "audio_hw_if"
43
44/**
45 * List of known audio HAL modules. This is the base name of the audio HAL
46 * library composed of the "audio." prefix, one of the base names below and
47 * a suffix specific to the device.
48 * e.g: audio.primary.goldfish.so or audio.a2dp.default.so
49 */
50
51#define AUDIO_HARDWARE_MODULE_ID_PRIMARY "primary"
52#define AUDIO_HARDWARE_MODULE_ID_A2DP "a2dp"
53#define AUDIO_HARDWARE_MODULE_ID_USB "usb"
54
55/**************************************/
56
57/**
58 *  standard audio parameters that the HAL may need to handle
59 */
60
61/**
62 *  audio device parameters
63 */
64
65/* BT SCO Noise Reduction + Echo Cancellation parameters */
66#define AUDIO_PARAMETER_KEY_BT_NREC "bt_headset_nrec"
67#define AUDIO_PARAMETER_VALUE_ON "on"
68#define AUDIO_PARAMETER_VALUE_OFF "off"
69
70/* TTY mode selection */
71#define AUDIO_PARAMETER_KEY_TTY_MODE "tty_mode"
72#define AUDIO_PARAMETER_VALUE_TTY_OFF "tty_off"
73#define AUDIO_PARAMETER_VALUE_TTY_VCO "tty_vco"
74#define AUDIO_PARAMETER_VALUE_TTY_HCO "tty_hco"
75#define AUDIO_PARAMETER_VALUE_TTY_FULL "tty_full"
76
77/* A2DP sink address set by framework */
78#define AUDIO_PARAMETER_A2DP_SINK_ADDRESS "a2dp_sink_address"
79
80/**
81 *  audio stream parameters
82 */
83
84#define AUDIO_PARAMETER_STREAM_ROUTING "routing"
85#define AUDIO_PARAMETER_STREAM_FORMAT "format"
86#define AUDIO_PARAMETER_STREAM_CHANNELS "channels"
87#define AUDIO_PARAMETER_STREAM_FRAME_COUNT "frame_count"
88#define AUDIO_PARAMETER_STREAM_INPUT_SOURCE "input_source"
89
90/**************************************/
91
92/* common audio stream parameters and operations */
93struct audio_stream {
94
95    /**
96     * sampling rate is in Hz - eg. 44100
97     */
98    uint32_t (*get_sample_rate)(const struct audio_stream *stream);
99
100    /* currently unused - use set_parameters with key
101     *    AUDIO_PARAMETER_STREAM_SAMPLING_RATE
102     */
103    int (*set_sample_rate)(struct audio_stream *stream, uint32_t rate);
104
105    /**
106     * size of output buffer in bytes - eg. 4800
107     */
108    size_t (*get_buffer_size)(const struct audio_stream *stream);
109
110    /**
111     * the channel mask -
112     *  e.g. AUDIO_CHANNEL_OUT_STEREO or AUDIO_CHANNEL_IN_STEREO
113     */
114    uint32_t (*get_channels)(const struct audio_stream *stream);
115
116    /**
117     * audio format - eg. AUDIO_FORMAT_PCM_16_BIT
118     */
119    audio_format_t (*get_format)(const struct audio_stream *stream);
120
121    /* currently unused - use set_parameters with key
122     *     AUDIO_PARAMETER_STREAM_FORMAT
123     */
124    int (*set_format)(struct audio_stream *stream, audio_format_t format);
125
126    /**
127     * Put the audio hardware input/output into standby mode.
128     * Returns 0 on success and <0 on failure.
129     */
130    int (*standby)(struct audio_stream *stream);
131
132    /** dump the state of the audio input/output device */
133    int (*dump)(const struct audio_stream *stream, int fd);
134
135    audio_devices_t (*get_device)(const struct audio_stream *stream);
136    int (*set_device)(struct audio_stream *stream, audio_devices_t device);
137
138    /**
139     * set/get audio stream parameters. The function accepts a list of
140     * parameter key value pairs in the form: key1=value1;key2=value2;...
141     *
142     * Some keys are reserved for standard parameters (See AudioParameter class)
143     *
144     * If the implementation does not accept a parameter change while
145     * the output is active but the parameter is acceptable otherwise, it must
146     * return -ENOSYS.
147     *
148     * The audio flinger will put the stream in standby and then change the
149     * parameter value.
150     */
151    int (*set_parameters)(struct audio_stream *stream, const char *kv_pairs);
152
153    /*
154     * Returns a pointer to a heap allocated string. The caller is responsible
155     * for freeing the memory for it.
156     */
157    char * (*get_parameters)(const struct audio_stream *stream,
158                             const char *keys);
159    int (*add_audio_effect)(const struct audio_stream *stream,
160                             effect_handle_t effect);
161    int (*remove_audio_effect)(const struct audio_stream *stream,
162                             effect_handle_t effect);
163};
164typedef struct audio_stream audio_stream_t;
165
166/**
167 * audio_stream_out is the abstraction interface for the audio output hardware.
168 *
169 * It provides information about various properties of the audio output
170 * hardware driver.
171 */
172
173struct audio_stream_out {
174    struct audio_stream common;
175
176    /**
177     * return the audio hardware driver latency in milli seconds.
178     */
179    uint32_t (*get_latency)(const struct audio_stream_out *stream);
180
181    /**
182     * Use this method in situations where audio mixing is done in the
183     * hardware. This method serves as a direct interface with hardware,
184     * allowing you to directly set the volume as apposed to via the framework.
185     * This method might produce multiple PCM outputs or hardware accelerated
186     * codecs, such as MP3 or AAC.
187     */
188    int (*set_volume)(struct audio_stream_out *stream, float left, float right);
189
190    /**
191     * write audio buffer to driver. Returns number of bytes written
192     */
193    ssize_t (*write)(struct audio_stream_out *stream, const void* buffer,
194                     size_t bytes);
195
196    /* return the number of audio frames written by the audio dsp to DAC since
197     * the output has exited standby
198     */
199    int (*get_render_position)(const struct audio_stream_out *stream,
200                               uint32_t *dsp_frames);
201
202    /**
203     * get the local time at which the next write to the audio driver will be
204     * presented
205     */
206    int (*get_next_write_timestamp)(const struct audio_stream_out *stream,
207                                    int64_t *timestamp);
208
209};
210typedef struct audio_stream_out audio_stream_out_t;
211
212struct audio_stream_in {
213    struct audio_stream common;
214
215    /** set the input gain for the audio driver. This method is for
216     *  for future use */
217    int (*set_gain)(struct audio_stream_in *stream, float gain);
218
219    /** read audio buffer in from audio driver */
220    ssize_t (*read)(struct audio_stream_in *stream, void* buffer,
221                    size_t bytes);
222
223    /**
224     * Return the amount of input frames lost in the audio driver since the
225     * last call of this function.
226     * Audio driver is expected to reset the value to 0 and restart counting
227     * upon returning the current value by this function call.
228     * Such loss typically occurs when the user space process is blocked
229     * longer than the capacity of audio driver buffers.
230     *
231     * Unit: the number of input audio frames
232     */
233    uint32_t (*get_input_frames_lost)(struct audio_stream_in *stream);
234};
235typedef struct audio_stream_in audio_stream_in_t;
236
237/**
238 * return the frame size (number of bytes per sample).
239 */
240static inline size_t audio_stream_frame_size(struct audio_stream *s)
241{
242    size_t chan_samp_sz;
243
244    switch (s->get_format(s)) {
245    case AUDIO_FORMAT_PCM_16_BIT:
246        chan_samp_sz = sizeof(int16_t);
247        break;
248    case AUDIO_FORMAT_PCM_8_BIT:
249    default:
250        chan_samp_sz = sizeof(int8_t);
251        break;
252    }
253
254    return popcount(s->get_channels(s)) * chan_samp_sz;
255}
256
257
258/**********************************************************************/
259
260/**
261 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
262 * and the fields of this data structure must begin with hw_module_t
263 * followed by module specific information.
264 */
265struct audio_module {
266    struct hw_module_t common;
267};
268
269struct audio_hw_device {
270    struct hw_device_t common;
271
272    /**
273     * used by audio flinger to enumerate what devices are supported by
274     * each audio_hw_device implementation.
275     *
276     * Return value is a bitmask of 1 or more values of audio_devices_t
277     */
278    uint32_t (*get_supported_devices)(const struct audio_hw_device *dev);
279
280    /**
281     * check to see if the audio hardware interface has been initialized.
282     * returns 0 on success, -ENODEV on failure.
283     */
284    int (*init_check)(const struct audio_hw_device *dev);
285
286    /** set the audio volume of a voice call. Range is between 0.0 and 1.0 */
287    int (*set_voice_volume)(struct audio_hw_device *dev, float volume);
288
289    /**
290     * set the audio volume for all audio activities other than voice call.
291     * Range between 0.0 and 1.0. If any value other than 0 is returned,
292     * the software mixer will emulate this capability.
293     */
294    int (*set_master_volume)(struct audio_hw_device *dev, float volume);
295
296    /**
297     * Get the current master volume value for the HAL, if the HAL supports
298     * master volume control.  AudioFlinger will query this value from the
299     * primary audio HAL when the service starts and use the value for setting
300     * the initial master volume across all HALs.  HALs which do not support
301     * this method should may leave it set to NULL.
302     */
303    int (*get_master_volume)(struct audio_hw_device *dev, float *volume);
304
305    /**
306     * set_mode is called when the audio mode changes. AUDIO_MODE_NORMAL mode
307     * is for standard audio playback, AUDIO_MODE_RINGTONE when a ringtone is
308     * playing, and AUDIO_MODE_IN_CALL when a call is in progress.
309     */
310    int (*set_mode)(struct audio_hw_device *dev, audio_mode_t mode);
311
312    /* mic mute */
313    int (*set_mic_mute)(struct audio_hw_device *dev, bool state);
314    int (*get_mic_mute)(const struct audio_hw_device *dev, bool *state);
315
316    /* set/get global audio parameters */
317    int (*set_parameters)(struct audio_hw_device *dev, const char *kv_pairs);
318
319    /*
320     * Returns a pointer to a heap allocated string. The caller is responsible
321     * for freeing the memory for it.
322     */
323    char * (*get_parameters)(const struct audio_hw_device *dev,
324                             const char *keys);
325
326    /* Returns audio input buffer size according to parameters passed or
327     * 0 if one of the parameters is not supported
328     */
329    size_t (*get_input_buffer_size)(const struct audio_hw_device *dev,
330                                    uint32_t sample_rate, audio_format_t format,
331                                    int channel_count);
332
333    /** This method creates and opens the audio hardware output stream */
334    int (*open_output_stream)(struct audio_hw_device *dev, uint32_t devices,
335                              audio_format_t *format, uint32_t *channels,
336                              uint32_t *sample_rate,
337                              struct audio_stream_out **out);
338
339    void (*close_output_stream)(struct audio_hw_device *dev,
340                                struct audio_stream_out* out);
341
342    /** This method creates and opens the audio hardware input stream */
343    int (*open_input_stream)(struct audio_hw_device *dev, uint32_t devices,
344                             audio_format_t *format, uint32_t *channels,
345                             uint32_t *sample_rate,
346                             audio_in_acoustics_t acoustics,
347                             struct audio_stream_in **stream_in);
348
349    void (*close_input_stream)(struct audio_hw_device *dev,
350                               struct audio_stream_in *in);
351
352    /** This method dumps the state of the audio hardware */
353    int (*dump)(const struct audio_hw_device *dev, int fd);
354};
355typedef struct audio_hw_device audio_hw_device_t;
356
357/** convenience API for opening and closing a supported device */
358
359static inline int audio_hw_device_open(const struct hw_module_t* module,
360                                       struct audio_hw_device** device)
361{
362    return module->methods->open(module, AUDIO_HARDWARE_INTERFACE,
363                                 (struct hw_device_t**)device);
364}
365
366static inline int audio_hw_device_close(struct audio_hw_device* device)
367{
368    return device->common.close(&device->common);
369}
370
371
372__END_DECLS
373
374#endif  // ANDROID_AUDIO_INTERFACE_H
375