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runtime->hw在哪里初始化？

Posted on 2016-03-03 19:24  思禽  阅读(643)  评论(0)    收藏  举报

runtime->hw的初始化时在打开pcm设备时完成的，代码：

snd_pcm_playback_open() --->
snd_pcm_open() --->
snd_pcm_open_file() --->
snd_pcm_open_substream() --->
substream->ops->open() --->
dpcm_fe_dai_open() --->
dpcm_fe_dai_startup() --->
soc_pcm_open() --->
platform->driver->ops->open(), 这里会针对不同应用调用其platform component的open函数，有如下这些：

/* 播放音乐，msm-pcm-q6-v2.c */
static int msm_pcm_open(struct snd_pcm_substream *substream)
{
	......
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		runtime->hw = msm_pcm_hardware_playback;
	else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
		runtime->hw = msm_pcm_hardware_capture;
	......
}

 

/* 通话，msm-pcm-voice-v2.c */
static int msm_pcm_open(struct snd_pcm_substream *substream)
{
	......
	runtime->hw = msm_pcm_hardware;
	......
}

　　

/* Loopback，msm-pcm-loopback-v2.c */
static int msm_pcm_open(struct snd_pcm_substream *substream)
{
	......
	snd_soc_set_runtime_hwparams(substream, &dummy_pcm_hardware);
	......
}

 

后续在通过ioctl设置hw params时，会根据约束条件对应用层传入的runtime->hw的params做进一步调整。。。。。。