ASoC: SOF: pcm: add pending_stop state variable

Add a state variable to keep track of delayed stops, in case
pcm_ops->platform_stop_during_hw_free is set.

This patch should be iso-functionality, possibly removing no-op
cases. The main purpose of this new state variable is to prepare a
follow-up patch to reset all PCM and DMAs in case of stop/prepare xrun
sequences.
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://msgid.link/r/20240402151828.175002-16-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/pcm.c

@@ -276,6 +276,8 @@ static int sof_pcm_trigger(struct snd_soc_component *component,
 	dev_dbg(component->dev, "pcm: trigger stream %d dir %d cmd %d\n",
 		spcm->pcm.pcm_id, substream->stream, cmd);
 
+	spcm->pending_stop[substream->stream] = false;
+
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		ipc_first = true;
@@ -345,6 +347,15 @@ static int sof_pcm_trigger(struct snd_soc_component *component,
 		/* invoke platform trigger to stop DMA even if pcm_ops isn't set or if it failed */
 		if (!pcm_ops || !pcm_ops->platform_stop_during_hw_free)
 			snd_sof_pcm_platform_trigger(sdev, substream, cmd);
+
+		/*
+		 * set the pending_stop flag to indicate that pipeline stop has been delayed.
+		 * This will be used later to stop the pipelines during prepare when recovering
+		 * from xruns.
+		 */
+		if (pcm_ops && pcm_ops->platform_stop_during_hw_free &&
+		    cmd == SNDRV_PCM_TRIGGER_STOP)
+			spcm->pending_stop[substream->stream] = true;
 		break;
 	default:
 		break;

sound/soc/sof/sof-audio.c

@@ -852,6 +852,7 @@ int sof_pcm_stream_free(struct snd_sof_dev *sdev, struct snd_pcm_substream *subs
 		}
 
 		spcm->prepared[substream->stream] = false;
+		spcm->pending_stop[substream->stream] = false;
 	}
 
 	/* reset the DMA */

sound/soc/sof/sof-audio.h

@@ -342,6 +342,7 @@ struct snd_sof_pcm {
 	struct list_head list;	/* list in sdev pcm list */
 	struct snd_pcm_hw_params params[2];
 	bool prepared[2]; /* PCM_PARAMS set successfully */
+	bool pending_stop[2]; /* only used if (!pcm_ops->platform_stop_during_hw_free) */
 };
 
 struct snd_sof_led_control {