> +static int q6apm_dai_prepare(struct snd_soc_component *component,
> + struct snd_pcm_substream *substream)
> +{
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + struct q6apm_dai_rtd *prtd = runtime->private_data;
> + struct audioreach_module_config cfg;
> + struct device *dev = component->dev;
> + struct q6apm_dai_data *pdata;
> + int ret;
> +
> + pdata = snd_soc_component_get_drvdata(component);
> + if (!pdata)
> + return -EINVAL;
> +
> + if (!prtd || !prtd->graph) {
> + dev_err(dev, "%s: private data null or audio client freed\n", __func__);
> + return -EINVAL;
> + }
> +
> + cfg.direction = substream->stream;
> + cfg.sample_rate = runtime->rate;
> + cfg.num_channels = runtime->channels;
> + cfg.bit_width = prtd->bits_per_sample;
> +
> + prtd->pcm_count = snd_pcm_lib_period_bytes(substream);
> + prtd->pos = 0;
> + /* rate and channels are sent to audio driver */
> + ret = q6apm_graph_media_format_shmem(prtd->graph, &cfg);
> + if (ret < 0) {
> + dev_err(dev, "%s: q6apm_open_write failed\n", __func__);
> + return ret;
> + }
> +
> + ret = q6apm_graph_media_format_pcm(prtd->graph, &cfg);
> + if (ret < 0)
> + dev_err(dev, "%s: CMD Format block failed\n", __func__);
> +
> + ret = q6apm_map_memory_regions(prtd->graph, substream->stream, prtd->phys,
> + (prtd->pcm_size / prtd->periods), prtd->periods);
> +
> + if (ret < 0) {
> + dev_err(dev, "Audio Start: Buffer Allocation failed rc = %d\n", ret);
> + return -ENOMEM;
> + }
> +
> + ret = q6apm_graph_prepare(prtd->graph);
> + if (ret) {
> + dev_err(dev, "Failed to prepare Graph %d\n", ret);
> + return ret;
> + }
> +
> + ret = q6apm_graph_start(prtd->graph);
> + if (ret) {
> + dev_err(dev, "Failed to Start Graph %d\n", ret);
> + return ret;
> + }
> +
> + if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
> + int i;
> + /* Queue the buffers for Capture ONLY after graph is started */
> + for (i = 0; i < runtime->periods; i++)
> + q6apm_read(prtd->graph);
> +
> + }
> +
> + prtd->state = Q6APM_STREAM_RUNNING;
you should probably explain why a stream moves to the 'RUNNING' state in
a .prepare() callback, instead of TRIGGER_START?
> +
> + return 0;
> +}
> +
> +static int q6apm_dai_trigger(struct snd_soc_component *component,
> + struct snd_pcm_substream *substream, int cmd)
> +{
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + struct q6apm_dai_rtd *prtd = runtime->private_data;
> + int ret = 0;
> +
> + switch (cmd) {
> + case SNDRV_PCM_TRIGGER_START:
> + case SNDRV_PCM_TRIGGER_RESUME:
> + case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> + /* start writing buffers for playback only as we already queued capture buffers */
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + ret = q6apm_write_async(prtd->graph, prtd->pcm_count, 0, 0, 0);
> + break;
> + case SNDRV_PCM_TRIGGER_STOP:
> + /* TODO support be handled via SoftPause Module */
> + prtd->state = Q6APM_STREAM_STOPPED;
> + break;
> + case SNDRV_PCM_TRIGGER_SUSPEND:
> + case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + return ret;
> +}
