Lines Matching +full:bt +full:- +full:pcm +full:- +full:int +full:- +full:params
2 Dynamic PCM
8 Dynamic PCM allows an ALSA PCM device to digitally route its PCM audio to
9 various digital endpoints during the PCM stream runtime. e.g. PCM0 can route
16 determine the path used by each ALSA PCM.
18 DPCM re-uses all the existing component codec, platform and DAI drivers without
23 -------------------------------------
26 document for all examples :-
32 PCM0 <------------> * * <----DAI0-----> Codec Headset
34 PCM1 <------------> * * <----DAI1-----> Codec Speakers
36 PCM2 <------------> * * <----DAI2-----> MODEM
38 PCM3 <------------> * * <----DAI3-----> BT
40 * * <----DAI4-----> DMIC
42 * * <----DAI5-----> FM
47 modem. This sound card exposes 4 DSP front end (FE) ALSA PCM devices and
48 supports 6 back end (BE) DAIs. Each FE PCM can digitally route audio data to any
49 of the BE DAIs. The FE PCM devices can also route audio to more than 1 BE DAI.
53 Example - DPCM Switching playback from DAI0 to DAI1
54 ---------------------------------------------------
59 Playback on PCM0 to Headset would look like :-
65 PCM1 <------------> * * <----DAI1-----> Codec Speakers
67 PCM2 <------------> * * <----DAI2-----> MODEM
69 PCM3 <------------> * * <----DAI3-----> BT
71 * * <----DAI4-----> DMIC
73 * * <----DAI5-----> FM
76 The headset is removed from the jack by user so the speakers must now be used :-
80 PCM0 <============> * * <----DAI0-----> Codec Headset
82 PCM1 <------------> * * <====DAI1=====> Codec Speakers
84 PCM2 <------------> * * <----DAI2-----> MODEM
86 PCM3 <------------> * * <----DAI3-----> BT
88 * * <----DAI4-----> DMIC
90 * * <----DAI5-----> FM
93 The audio driver processes this as follows :-
99 3. DPCM runs the PCM trigger(stop), hw_free(), shutdown() operations on DAI0
104 5. DPCM runs the PCM ops for startup(), hw_params(), prepare() and
108 and then DPCM will take care of managing the DAI PCM operations to either bring
117 except that we also have to :-
121 2. Define any FE/BE PCM operations.
127 -------------------
133 PCM0 <------------> * * <----DAI0-----> Codec Headset
135 PCM1 <------------> * * <----DAI1-----> Codec Speakers
137 PCM2 <------------> * * <----DAI2-----> MODEM
139 PCM3 <------------> * * <----DAI3-----> BT
141 * * <----DAI4-----> DMIC
143 * * <----DAI5-----> FM
147 FE DAI links are defined as follows :-
155 .platform_name = "dsp-audio",
156 .codec_name = "snd-soc-dummy",
157 .codec_dai_name = "snd-soc-dummy-dai",
176 The BE DAIs are configured as follows :-
183 .cpu_dai_name = "ssp-dai.0",
184 .platform_name = "snd-soc-dummy",
186 .codec_name = "rt5640.0-001c",
187 .codec_dai_name = "rt5640-aif1",
204 like a BT phone call :-
208 PCM0 <------------> * * <----DAI0-----> Codec Headset
210 PCM1 <------------> * * <----DAI1-----> Codec Speakers
212 PCM2 <------------> * * <====DAI2=====> MODEM
214 PCM3 <------------> * * <====DAI3=====> BT
216 * * <----DAI4-----> DMIC
218 * * <----DAI5-----> FM
221 This allows the host CPU to sleep while the DSP, MODEM DAI and the BT DAI are
231 FE/BE PCM operations
232 --------------------
234 The BE above also exports some PCM operations and a ``fixup`` callback. The fixup
236 FE hw params. i.e. the DSP may perform SRC or ASRC from the FE to BE.
238 e.g. DSP converts all FE hw params to run at fixed rate of 48k, 16bit, stereo for
244 static int dai0_fixup(struct snd_soc_pcm_runtime *rtd,
245 struct snd_pcm_hw_params *params)
247 struct snd_interval *rate = hw_param_interval(params,
249 struct snd_interval *channels = hw_param_interval(params,
253 rate->min = rate->max = 48000;
254 channels->min = channels->max = 2;
257 params_set_format(params, SNDRV_PCM_FORMAT_S16_LE);
261 The other PCM operation are the same as for regular DAI links. Use as necessary.
265 ------------------------
269 has to be set explicitly in the driver :-
272 /* BE for codec Headset - DAI0 is dummy and managed by DSP FW */
282 implement :-
284 1. Front End PCM DAIs - i.e. struct snd_soc_dai_driver.
298 have :-
308 Hostless PCM streams
311 A hostless PCM stream is a stream that is not routed through the host CPU. An
316 PCM0 <------------> * * <----DAI0-----> Codec Headset
318 PCM1 <------------> * * <====DAI1=====> Codec Speakers/Mic
320 PCM2 <------------> * * <====DAI2=====> MODEM
322 PCM3 <------------> * * <----DAI3-----> BT
324 * * <----DAI4-----> DMIC
326 * * <----DAI5-----> FM
329 In this case the PCM data is routed via the DSP. The host CPU in this use case
332 The host can control the hostless link either by :-
334 1. Configuring the link as a CODEC <-> CODEC style link. In this case the link
340 graph. Control is then carried out by the FE as regular PCM operations.
342 userspace code to control the link. Its recommended to use CODEC<->CODEC
343 unless your HW needs more fine grained sequencing of the PCM ops.
346 CODEC <-> CODEC link
347 --------------------
367 .codec_dai_name = "modem-aif1",
371 .params = &dai_params,
376 valid path and then calls the PCM operations to start the link. DAPM will also
377 call the appropriate PCM operations to disable the DAI when the path is no
382 -----------
384 The DAI link(s) are enabled by a FE that does not read or write any PCM data.
386 DAI links. The DAI links will be started when the FE PCM is started and stopped
387 when the FE PCM is stopped. Note that the FE PCM cannot read or write data in