ASoC: SOF: Support for echoref (virtual DAI)

Merge series from Peter Ujfalusi <peter.ujfalusi@linux.intel.com>:

The series adds support for echo reference functionality by allowing
the capturing of playback audio right before it leaves the DSP.
For this to work correctly we need a virtual DAI that is also connected
to the echo reference capture device and in absence of playback a
signal generator generates silence to allow the capture to run.
When the real playback starts, application will start to receive the
playback audio to be usable for echo reference.

Author: broonie

include/uapi/sound/sof/tokens.h

@@ -56,6 +56,9 @@
 #define SOF_TKN_SCHED_LP_MODE			207
 #define SOF_TKN_SCHED_MEM_USAGE			208
 #define SOF_TKN_SCHED_USE_CHAIN_DMA		209
+#define SOF_TKN_SCHED_KCPS			210
+#define SOF_TKN_SCHED_DIRECTION			211
+#define SOF_TKN_SCHED_DIRECTION_VALID		212
 
 /* volume */
 #define SOF_TKN_VOLUME_RAMP_STEP_TYPE		250

sound/soc/intel/boards/sof_sdw.c

@@ -1186,6 +1186,34 @@ static int create_bt_dailinks(struct snd_soc_card *card,
 	return 0;
 }
 
+static int create_echoref_dailink(struct snd_soc_card *card,
+				  struct snd_soc_dai_link **dai_links, int *be_id)
+{
+	struct device *dev = card->dev;
+	int ret;
+	char *name = devm_kasprintf(dev, GFP_KERNEL, "Loopback_Virtual");
+
+	if (!name)
+		return -ENOMEM;
+
+	/*
+	 * use dummy DAI names as this won't be connected to an actual DAI but just to establish a
+	 * fe <-> be connection for loopback capture for echo reference
+	 */
+	ret = asoc_sdw_init_simple_dai_link(dev, *dai_links, be_id, name,
+					    0, 1, "Loopback Virtual Pin", "dummy",
+					    snd_soc_dummy_dlc.name, snd_soc_dummy_dlc.dai_name,
+					    1, NULL, NULL);
+	if (ret)
+		return ret;
+
+	(*dai_links)++;
+
+	dev_dbg(dev, "Added echo reference DAI link\n");
+
+	return 0;
+}
+
 static int sof_card_dai_links_create(struct snd_soc_card *card)
 {
 	struct device *dev = card->dev;
@@ -1294,8 +1322,12 @@ static int sof_card_dai_links_create(struct snd_soc_card *card)
 		goto err_end;
 	}
 
-	/* allocate BE dailinks */
-	num_links = sdw_be_num + ssp_num + dmic_num + hdmi_num + bt_num;
+	/*
+	 * allocate BE dailinks, add an extra DAI link for echo reference capture.
+	 * This should be the last DAI link and it is expected both for monolithic
+	 * and functional SOF topologies to support echo reference.
+	 */
+	num_links = sdw_be_num + ssp_num + dmic_num + hdmi_num + bt_num + 1;
 	dai_links = devm_kcalloc(dev, num_links, sizeof(*dai_links), GFP_KERNEL);
 	if (!dai_links) {
 		ret = -ENOMEM;
@@ -1344,6 +1376,13 @@ static int sof_card_dai_links_create(struct snd_soc_card *card)
 			goto err_end;
 	}
 
+	/* dummy echo ref link. keep this as the last DAI link. The DAI link ID does not matter */
+	ret = create_echoref_dailink(card, &dai_links, &be_id);
+	if (ret) {
+		dev_err(dev, "failed to create echo ref dai link: %d\n", ret);
+		goto err_end;
+	}
+
 	WARN_ON(codec_conf != card->codec_conf + card->num_configs);
 	WARN_ON(dai_links != card->dai_link + card->num_links);
 

sound/soc/sof/intel/hda-dai.c

@@ -70,12 +70,22 @@ static const struct hda_dai_widget_dma_ops *
 hda_dai_get_ops(struct snd_pcm_substream *substream, struct snd_soc_dai *cpu_dai)
 {
 	struct snd_soc_dapm_widget *w = snd_soc_dai_get_widget(cpu_dai, substream->stream);
-	struct snd_sof_widget *swidget = w->dobj.private;
+	struct snd_sof_widget *swidget;
 	struct snd_sof_dev *sdev;
 	struct snd_sof_dai *sdai;
 
-	sdev = widget_to_sdev(w);
+	/*
+	 * this is unlikely if the topology and the machine driver DAI links match.
+	 * But if there's a missing DAI link in topology, this will prevent a NULL pointer
+	 * dereference later on.
+	 */
+	if (!w) {
+		dev_err(cpu_dai->dev, "%s: widget is NULL\n", __func__);
+		return NULL;
+	}
 
+	sdev = widget_to_sdev(w);
+	swidget = w->dobj.private;
 	if (!swidget) {
 		dev_err(sdev->dev, "%s: swidget is NULL\n", __func__);
 		return NULL;
@@ -856,6 +866,14 @@ struct snd_soc_dai_driver skl_dai[] = {
 		.channels_max = 4,
 	},
 },
+{
+	/* Virtual CPU DAI for Echo reference */
+	.name = "Loopback Virtual Pin",
+	.capture = {
+		.channels_min = 1,
+		.channels_max = 2,
+	},
+},
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_AUDIO_CODEC)
 {
 	.name = "iDisp1 Pin",

sound/soc/sof/intel/hda.h

@@ -418,10 +418,10 @@
 	(HDA_DSP_BDL_SIZE / sizeof(struct sof_intel_dsp_bdl))
 
 /* Number of DAIs */
-#define SOF_SKL_NUM_DAIS_NOCODEC	8
+#define SOF_SKL_NUM_DAIS_NOCODEC	9
 
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_AUDIO_CODEC)
-#define SOF_SKL_NUM_DAIS		15
+#define SOF_SKL_NUM_DAIS		16
 #else
 #define SOF_SKL_NUM_DAIS		SOF_SKL_NUM_DAIS_NOCODEC
 #endif

sound/soc/sof/ipc4-topology.c

@@ -76,6 +76,10 @@ static const struct sof_topology_token ipc4_sched_tokens[] = {
 		offsetof(struct sof_ipc4_pipeline, core_id)},
 	{SOF_TKN_SCHED_PRIORITY, SND_SOC_TPLG_TUPLE_TYPE_WORD, get_token_u32,
 		offsetof(struct sof_ipc4_pipeline, priority)},
+	{SOF_TKN_SCHED_DIRECTION, SND_SOC_TPLG_TUPLE_TYPE_WORD, get_token_u32,
+		offsetof(struct sof_ipc4_pipeline, direction)},
+	{SOF_TKN_SCHED_DIRECTION, SND_SOC_TPLG_TUPLE_TYPE_BOOL, get_token_u16,
+		offsetof(struct sof_ipc4_pipeline, direction_valid)},
 };
 
 static const struct sof_topology_token pipeline_tokens[] = {
@@ -939,6 +943,10 @@ static int sof_ipc4_widget_setup_comp_pipeline(struct snd_sof_widget *swidget)
 
 	swidget->core = pipeline->core_id;
 	spipe->core_mask |= BIT(pipeline->core_id);
+	if (pipeline->direction_valid) {
+		spipe->direction = pipeline->direction;
+		spipe->direction_valid = true;
+	}
 
 	if (pipeline->use_chain_dma) {
 		dev_dbg(scomp->dev, "Set up chain DMA for %s\n", swidget->widget->name);
@@ -954,9 +962,9 @@ static int sof_ipc4_widget_setup_comp_pipeline(struct snd_sof_widget *swidget)
 		goto err;
 	}
 
-	dev_dbg(scomp->dev, "pipeline '%s': id %d, pri %d, core_id %u, lp mode %d\n",
+	dev_dbg(scomp->dev, "pipeline '%s': id %d, pri %d, core_id %u, lp mode %d direction %d\n",
 		swidget->widget->name, swidget->pipeline_id,
-		pipeline->priority, pipeline->core_id, pipeline->lp_mode);
+		pipeline->priority, pipeline->core_id, pipeline->lp_mode, pipeline->direction);
 
 	swidget->private = pipeline;
 
@@ -2004,6 +2012,25 @@ sof_ipc4_prepare_dai_copier(struct snd_sof_dev *sdev, struct snd_sof_dai *dai,
 	return ret;
 }
 
+static void sof_ipc4_host_config(struct snd_sof_dev *sdev, struct snd_sof_widget *swidget,
+				 struct snd_sof_platform_stream_params *platform_params)
+{
+	struct sof_ipc4_copier *ipc4_copier = (struct sof_ipc4_copier *)swidget->private;
+	struct snd_sof_widget *pipe_widget = swidget->spipe->pipe_widget;
+	struct sof_ipc4_copier_data *copier_data = &ipc4_copier->data;
+	struct sof_ipc4_pipeline *pipeline = pipe_widget->private;
+	u32 host_dma_id = platform_params->stream_tag - 1;
+
+	if (pipeline->use_chain_dma) {
+		pipeline->msg.primary &= ~SOF_IPC4_GLB_CHAIN_DMA_HOST_ID_MASK;
+		pipeline->msg.primary |= SOF_IPC4_GLB_CHAIN_DMA_HOST_ID(host_dma_id);
+		return;
+	}
+
+	copier_data->gtw_cfg.node_id &= ~SOF_IPC4_NODE_INDEX_MASK;
+	copier_data->gtw_cfg.node_id |=	SOF_IPC4_NODE_INDEX(host_dma_id);
+}
+
 static int
 sof_ipc4_prepare_copier_module(struct snd_sof_widget *swidget,
 			       struct snd_pcm_hw_params *fe_params,
@@ -2726,12 +2753,14 @@ static int sof_ipc4_prepare_process_module(struct snd_sof_widget *swidget,
 	int input_fmt_index = 0;
 	int ret;
 
-	input_fmt_index = sof_ipc4_init_input_audio_fmt(sdev, swidget,
-							&process->base_config,
-							pipeline_params,
-							available_fmt);
-	if (input_fmt_index < 0)
-		return input_fmt_index;
+	if (available_fmt->num_input_formats) {
+		input_fmt_index = sof_ipc4_init_input_audio_fmt(sdev, swidget,
+								&process->base_config,
+								pipeline_params,
+								available_fmt);
+		if (input_fmt_index < 0)
+			return input_fmt_index;
+	}
 
 	/* Configure output audio format only if the module supports output */
 	if (available_fmt->num_output_formats) {
@@ -2740,12 +2769,28 @@ static int sof_ipc4_prepare_process_module(struct snd_sof_widget *swidget,
 		u32 out_ref_rate, out_ref_channels;
 		int out_ref_valid_bits, out_ref_type;
 
-		in_fmt = &available_fmt->input_pin_fmts[input_fmt_index].audio_fmt;
+		if (available_fmt->num_input_formats) {
+			in_fmt = &available_fmt->input_pin_fmts[input_fmt_index].audio_fmt;
 
-		out_ref_rate = in_fmt->sampling_frequency;
-		out_ref_channels = SOF_IPC4_AUDIO_FORMAT_CFG_CHANNELS_COUNT(in_fmt->fmt_cfg);
-		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);
+			out_ref_rate = in_fmt->sampling_frequency;
+			out_ref_channels =
+				SOF_IPC4_AUDIO_FORMAT_CFG_CHANNELS_COUNT(in_fmt->fmt_cfg);
+			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 {
+			/* for modules without input formats, use FE params as reference */
+			out_ref_rate = params_rate(fe_params);
+			out_ref_channels = params_channels(fe_params);
+			ret = sof_ipc4_get_sample_type(sdev, fe_params);
+			if (ret < 0)
+				return ret;
+			out_ref_type = (u32)ret;
+
+			out_ref_valid_bits = sof_ipc4_get_valid_bits(sdev, fe_params);
+			if (out_ref_valid_bits < 0)
+				return out_ref_valid_bits;
+		}
 
 		output_fmt_index = sof_ipc4_init_output_audio_fmt(sdev, swidget,
 								  &process->base_config,
@@ -2773,6 +2818,16 @@ static int sof_ipc4_prepare_process_module(struct snd_sof_widget *swidget,
 			if (ret)
 				return ret;
 		}
+
+		/* set base cfg to match the first output format if there are no input formats */
+		if (!available_fmt->num_input_formats) {
+			struct sof_ipc4_audio_format *out_fmt;
+
+			out_fmt = &available_fmt->output_pin_fmts[0].audio_fmt;
+
+			/* copy output format */
+			memcpy(&process->base_config.audio_fmt, out_fmt, sizeof(*out_fmt));
+		}
 	}
 
 	sof_ipc4_dbg_module_audio_format(sdev->dev, swidget, available_fmt,
@@ -3929,4 +3984,5 @@ const struct sof_ipc_tplg_ops ipc4_tplg_ops = {
 	.dai_get_param = sof_ipc4_dai_get_param,
 	.tear_down_all_pipelines = sof_ipc4_tear_down_all_pipelines,
 	.link_setup = sof_ipc4_link_setup,
+	.host_config = sof_ipc4_host_config,
 };

sound/soc/sof/ipc4-topology.h

@@ -150,6 +150,8 @@ struct sof_ipc4_copier_config_set_sink_format {
  * @use_chain_dma: flag to indicate if the firmware shall use chained DMA
  * @msg: message structure for pipeline
  * @skip_during_fe_trigger: skip triggering this pipeline during the FE DAI trigger
+ * @direction_valid: flag indicating if valid direction is set in topology
+ * @direction: pipeline direction set in topology if direction_valid is true
  */
 struct sof_ipc4_pipeline {
 	uint32_t priority;
@@ -160,6 +162,8 @@ struct sof_ipc4_pipeline {
 	bool use_chain_dma;
 	struct sof_ipc4_msg msg;
 	bool skip_during_fe_trigger;
+	bool direction_valid;
+	u32 direction;
 };
 
 /**