[PATCH] ASoC: SOF: sof-audio: add support for setting up loopback routes

[PATCH] ASoC: SOF: sof-audio: add support for setting up loopback routes

[Peter Ujfalusi]

From: Chao Song <chao.song@linux.intel.com>

During route setup, playback stream routes are setup by going through
sink path, capture stream routes are set up by going through source path.
This is not sufficient to handle loopback cases between pipelines
configured with different directions, e.g. a sidetone or an amplifier
feedback connected to a speaker protection module. So, add the logic to
handle such routes between widgets that aren't in the list of DAPM widgets
associated with the same PCM.

Link: https://github.com/thesofproject/linux/issues/4042

Suggested-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Chao Song <chao.song@linux.intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
---
 sound/soc/sof/sof-audio.c | 61 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sof/sof-audio.c b/sound/soc/sof/sof-audio.c
index 6de388a8d0b8..4f12e137ff63 100644
--- a/sound/soc/sof/sof-audio.c
+++ b/sound/soc/sof/sof-audio.c
@@ -280,9 +280,11 @@ int sof_route_setup(struct snd_sof_dev *sdev, struct snd_soc_dapm_widget *wsourc
 static int sof_setup_pipeline_connections(struct snd_sof_dev *sdev,
 					  struct snd_soc_dapm_widget_list *list, int dir)
 {
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
 	struct snd_soc_dapm_widget *widget;
+	struct snd_sof_route *sroute;
 	struct snd_soc_dapm_path *p;
-	int ret;
+	int ret = 0;
 	int i;
 
 	/*
@@ -325,6 +327,63 @@ static int sof_setup_pipeline_connections(struct snd_sof_dev *sdev,
 		}
 	}
 
+	/*
+	 * The above loop handles connections between widgets that belong to the DAPM widget list.
+	 * This is not sufficient to handle loopback cases between pipelines configured with
+	 * different directions, e.g. a sidetone or an amplifier feedback connected to a speaker
+	 * protection module.
+	 */
+	list_for_each_entry(sroute, &sdev->route_list, list) {
+		bool src_widget_in_dapm_list, sink_widget_in_dapm_list;
+		struct snd_sof_widget *swidget;
+
+		if (sroute->setup)
+			continue;
+
+		src_widget_in_dapm_list = widget_in_list(list, sroute->src_widget->widget);
+		sink_widget_in_dapm_list = widget_in_list(list, sroute->sink_widget->widget);
+
+		/*
+		 * if both source and sink are in the DAPM list, the route must already have been
+		 * set up above. And if neither are in the DAPM list, the route shouldn't be
+		 * handled now.
+		 */
+		if (src_widget_in_dapm_list == sink_widget_in_dapm_list)
+			continue;
+
+		/*
+		 * At this point either the source widget or the sink widget is in the DAPM list
+		 * with a route that might need to be set up. Check the use_count of the widget
+		 * that is not in the DAPM list to confirm if it is in use currently before setting
+		 * up the route.
+		 */
+		if (src_widget_in_dapm_list)
+			swidget = sroute->sink_widget;
+		else
+			swidget = sroute->src_widget;
+
+		mutex_lock(&swidget->setup_mutex);
+		if (!swidget->use_count) {
+			mutex_unlock(&swidget->setup_mutex);
+			continue;
+		}
+
+		if (tplg_ops && tplg_ops->route_setup) {
+			/*
+			 * this route will get freed when either the source widget or the sink
+			 * widget is freed during hw_free
+			 */
+			ret = tplg_ops->route_setup(sdev, sroute);
+			if (!ret)
+				sroute->setup = true;
+		}
+
+		mutex_unlock(&swidget->setup_mutex);
+
+		if (ret < 0)
+			return ret;
+	}
+
 	return 0;
 }
 
-- 
2.39.2

Re: [PATCH] ASoC: SOF: sof-audio: add support for setting up loopback routes

[Mark Brown]

On Mon, 13 Mar 2023 12:13:02 +0200, Peter Ujfalusi wrote:
> During route setup, playback stream routes are setup by going through
> sink path, capture stream routes are set up by going through source path.
> This is not sufficient to handle loopback cases between pipelines
> configured with different directions, e.g. a sidetone or an amplifier
> feedback connected to a speaker protection module. So, add the logic to
> handle such routes between widgets that aren't in the list of DAPM widgets
> associated with the same PCM.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: SOF: sof-audio: add support for setting up loopback routes
      commit: 8cd3cb17fcf216cb859f86a00fff428fbcecc1d8

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark