ASoC: SOF: sof-audio: Traverse paths with virtual widgets

Today, we use virtual widgets in topology to represent aggregated DAI's
in the graph. So, when walking the list of DAPM widgets, when we
encounter a virtual widget, we end the walk there. Modify the logic to
allow walking past the virtual widgets without handling them during
prepare/unprepare/setup/free. This will be useful for the hostless
pipelines that use the virtual widget as the start of the playback
pipeline. For example, in the case of a tone generator playback
pipeline, we could have

virtual widget (type input) -> tone generator -> gain -> BE DAI

The virtual widget exists only to establish a FE <-> BE connection for
DPCM. So while walking the list of widgets, skip the virtual widget and
move on so that the tone generator and all of the other widgets
downstream can be handled.

But in order for this to work with the current use of virtual widgets to
represent aggregated DAI's, we also need to skip the aggregated DAI's
from being handled during prepare/unprepare/free/setup. Add a new helper
function to determine if a DAI widget is an aggregated DAI and skip past
the widget when walking the list of connected DAPM widgets.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Author: ranj063

sound/soc/sof/ipc4-topology.c

@@ -2773,9 +2773,9 @@ static int sof_ipc4_prepare_process_module(struct snd_sof_widget *swidget,
 			in_fmt = &available_fmt->input_pin_fmts[input_fmt_index].audio_fmt;
 
 			out_ref_rate = in_fmt->sampling_frequency;
-			out_ref_channels = 
+			out_ref_channels =
 				SOF_IPC4_AUDIO_FORMAT_CFG_CHANNELS_COUNT(in_fmt->fmt_cfg);
-			out_ref_valid_bits = 
+			out_ref_valid_bits =
 				SOF_IPC4_AUDIO_FORMAT_CFG_V_BIT_DEPTH(in_fmt->fmt_cfg);
 			out_ref_type = sof_ipc4_fmt_cfg_to_type(in_fmt->fmt_cfg);
 		} else {

sound/soc/sof/sof-audio.c

@@ -13,6 +13,21 @@
 #include "sof-audio.h"
 #include "ops.h"
 
+/*
+ * Check if a DAI widget is an aggregated DAI. Aggregated DAI's have names ending in numbers
+ * starting with 0. For example: in the case of a SDW speaker with 2 amps, the topology contains
+ * 2 DAI's names alh-copier.SDW1.Playback.0 and alh-copier-SDW1.Playback.1. In this case, only the
+ * DAI alh-copier.SDW1.Playback.0 is set up in the firmware. The other DAI,
+ * alh-copier.SDW1.Playback.1 in topology is for the sake of completeness to show aggregation for
+ * the speaker amp and does not need any firmware configuration.
+ */
+static bool is_aggregated_dai(struct snd_sof_widget *swidget)
+{
+	return (WIDGET_IS_DAI(swidget->id) &&
+	        isdigit(swidget->widget->name[strlen(swidget->widget->name) - 1]) &&
+	        swidget->widget->name[strlen(swidget->widget->name) - 1] != '0');
+}
+
 static bool is_virtual_widget(struct snd_sof_dev *sdev, struct snd_soc_dapm_widget *widget,
 			      const char *func)
 {
@@ -399,11 +414,13 @@ sof_unprepare_widgets_in_path(struct snd_sof_dev *sdev, struct snd_soc_dapm_widg
 	const struct sof_ipc_tplg_widget_ops *widget_ops;
 	struct snd_soc_dapm_path *p;
 
-	if (is_virtual_widget(sdev, widget, __func__))
-		return;
-
 	/* skip if the widget is in use or if it is already unprepared */
-	if (!swidget || !swidget->prepared || swidget->use_count > 0)
+	if (!swidget || !swidget->prepared || swidget->use_count > 0 ||
+	    is_virtual_widget(sdev, widget, __func__))
+		goto sink_unprepare;
+
+	/* skip aggregated DAIs */
+	if(is_aggregated_dai(swidget))
 		goto sink_unprepare;
 
 	widget_ops = tplg_ops ? tplg_ops->widget : NULL;
@@ -440,7 +457,7 @@ sof_prepare_widgets_in_path(struct snd_sof_dev *sdev, struct snd_soc_dapm_widget
 	int ret;
 
 	if (is_virtual_widget(sdev, widget, __func__))
-		return 0;
+		goto sink_prepare;
 
 	widget_ops = tplg_ops ? tplg_ops->widget : NULL;
 	if (!widget_ops)
@@ -449,6 +466,10 @@ sof_prepare_widgets_in_path(struct snd_sof_dev *sdev, struct snd_soc_dapm_widget
 	if (!swidget || !widget_ops[widget->id].ipc_prepare || swidget->prepared)
 		goto sink_prepare;
 
+	/* skip aggregated DAIs */
+	if(is_aggregated_dai(swidget))
+		goto sink_prepare;
+
 	/* prepare the source widget */
 	ret = widget_ops[widget->id].ipc_prepare(swidget, fe_params, platform_params,
 					     pipeline_params, dir);
@@ -493,15 +514,19 @@ static int sof_free_widgets_in_path(struct snd_sof_dev *sdev, struct snd_soc_dap
 				    int dir, struct snd_sof_pcm *spcm)
 {
 	struct snd_soc_dapm_widget_list *list = spcm->stream[dir].list;
+	struct snd_sof_widget *swidget;
 	struct snd_soc_dapm_path *p;
 	int err;
 	int ret = 0;
 
 	if (is_virtual_widget(sdev, widget, __func__))
-		return 0;
+		goto sink_free;
 
-	if (widget->dobj.private) {
-		err = sof_widget_free(sdev, widget->dobj.private);
+	swidget = widget->dobj.private;
+
+	/* no need to free aggregated DAI widgets */
+	if (swidget && !is_aggregated_dai(swidget)) {
+		err = sof_widget_free(sdev, swidget);
 		if (err < 0)
 			ret = err;
 	}
@@ -540,12 +565,15 @@ static int sof_set_up_widgets_in_path(struct snd_sof_dev *sdev, struct snd_soc_d
 	int ret;
 
 	if (is_virtual_widget(sdev, widget, __func__))
-		return 0;
+		goto sink_setup;
 
 	if (swidget) {
 		int i;
 
-		ret = sof_widget_setup(sdev, widget->dobj.private);
+		if(is_aggregated_dai(swidget))
+			goto sink_setup;
+
+		ret = sof_widget_setup(sdev, swidget);
 		if (ret < 0)
 			return ret;