alsa调用

ALSA打开数据流程
    soc_pcm_open => cpu_dai->driver->ops->startup => platform->driver->ops->open => codec_dai->driver->ops->startup \

    => rtd->dai_link->ops->startup  

 

    ALSA的HW_param流程
    soc_pcm_hw_params => rtd->dai_link->ops->hw_params => codec_dai->driver->ops->hw_params => cpu_dai->driver->ops->hw_params \

    => platform->driver->ops->hw_params

 

    ALSA的Prepare流程
    snd_pcm_prepare => snd_pcm_action_nonatomic => snd_pcm_action_group => snd_pcm_do_prepare => substream->ops->prepare \

    => soc_pcm_prepare => rtd->dai_link->ops->prepare => platform->driver->ops->prepare => codec_dai->driver->ops->prepare \

           => cpu_dai->driver->ops->prepare  

 

    ALSA的Write流程
    snd_pcm_playback_ioctl => snd_pcm_playback_ioctl1 => SNDRV_PCM_IOCTL_WRITEN_FRAMES => snd_pcm_lib_writev => snd_pcm_lib_write1 \

    => |||| =>  snd_pcm_lib_writev_transfer => copy_from_user [copy user speace data to dma]  

    snd_pcm_start => snd_pcm_action => snd_pcm_action_group => snd_pcm_do_start =>  substream->ops->trigger

 

    ALSA的Trigger流程
    substream->ops->trigger => soc_pcm_trigger => codec_dai->driver->ops->trigger => platform->driver->ops->trigger \

    => cpu_dai->driver->ops->trigger

    

    ALSA的cset流程

    snd_ctl_ioctl => SNDRV_CTL_IOCTL_ELEM_WRITE => snd_ctl_elem_write_user => snd_ctl_elem_write => kctl->put => codec->write