ASoC: SOF: Add support for DSPless mode

Via the SOF_DBG_DSPLESS_MODE sof_debug flag the SOF stack can be asked to
not use the DSP for audio.

The core's support for DSPless mode is only going to be enabled if the
platform reports that it can be used without DSP.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Link: https://lore.kernel.org/r/20230404092115.27949-4-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/core.c

@@ -208,6 +208,11 @@ static int sof_probe_continue(struct snd_sof_dev *sdev)
 	/* set up platform component driver */
 	snd_sof_new_platform_drv(sdev);
 
+	if (sdev->dspless_mode_selected) {
+		sof_set_fw_state(sdev, SOF_DSPLESS_MODE);
+		goto skip_dsp_init;
+	}
+
 	/* register any debug/trace capabilities */
 	ret = snd_sof_dbg_init(sdev);
 	if (ret < 0) {
@@ -266,6 +271,7 @@ static int sof_probe_continue(struct snd_sof_dev *sdev)
 		dev_dbg(sdev->dev, "SOF firmware trace disabled\n");
 	}
 
+skip_dsp_init:
 	/* hereafter all FW boot flows are for PM reasons */
 	sdev->first_boot = false;
 
@@ -387,12 +393,18 @@ int snd_sof_device_probe(struct device *dev, struct snd_sof_pdata *plat_data)
 		return ret;
 
 	/* check all mandatory ops */
-	if (!sof_ops(sdev) || !sof_ops(sdev)->probe || !sof_ops(sdev)->run ||
-	    !sof_ops(sdev)->block_read || !sof_ops(sdev)->block_write ||
-	    !sof_ops(sdev)->send_msg || !sof_ops(sdev)->load_firmware ||
-	    !sof_ops(sdev)->ipc_msg_data) {
+	if (!sof_ops(sdev) || !sof_ops(sdev)->probe) {
+		sof_ops_free(sdev);
+		dev_err(dev, "missing mandatory ops\n");
+		return -EINVAL;
+	}
+
+	if (!sdev->dspless_mode_selected &&
+	    (!sof_ops(sdev)->run || !sof_ops(sdev)->block_read ||
+	     !sof_ops(sdev)->block_write || !sof_ops(sdev)->send_msg ||
+	     !sof_ops(sdev)->load_firmware || !sof_ops(sdev)->ipc_msg_data)) {
 		sof_ops_free(sdev);
-		dev_err(dev, "error: missing mandatory ops\n");
+		dev_err(dev, "missing mandatory DSP ops\n");
 		return -EINVAL;
 	}
 

sound/soc/sof/debug.c

@@ -370,6 +370,7 @@ static const struct soc_fw_state_info {
 	const char *name;
 } fw_state_dbg[] = {
 	{SOF_FW_BOOT_NOT_STARTED, "SOF_FW_BOOT_NOT_STARTED"},
+	{SOF_DSPLESS_MODE, "SOF_DSPLESS_MODE"},
 	{SOF_FW_BOOT_PREPARE, "SOF_FW_BOOT_PREPARE"},
 	{SOF_FW_BOOT_IN_PROGRESS, "SOF_FW_BOOT_IN_PROGRESS"},
 	{SOF_FW_BOOT_FAILED, "SOF_FW_BOOT_FAILED"},

sound/soc/sof/pcm.c

@@ -330,6 +330,11 @@ static int sof_pcm_trigger(struct snd_soc_component *component,
 			spcm->stream[substream->stream].suspend_ignored = true;
 			return 0;
 		}
+
+		/* On suspend the DMA must be stopped in DSPless mode */
+		if (sdev->dspless_mode_selected)
+			reset_hw_params = true;
+
 		fallthrough;
 	case SNDRV_PCM_TRIGGER_STOP:
 		ipc_first = true;
@@ -705,7 +710,6 @@ void snd_sof_new_platform_drv(struct snd_sof_dev *sdev)
 
 	pd->pcm_construct = sof_pcm_new;
 	pd->ignore_machine = drv_name;
-	pd->be_hw_params_fixup = sof_pcm_dai_link_fixup;
 	pd->be_pcm_base = SOF_BE_PCM_BASE;
 	pd->use_dai_pcm_id = true;
 	pd->topology_name_prefix = "sof";
@@ -714,4 +718,11 @@ void snd_sof_new_platform_drv(struct snd_sof_dev *sdev)
 	pd->module_get_upon_open = 1;
 
 	pd->legacy_dai_naming = 1;
+
+	/*
+	 * The fixup is only needed when the DSP is in use as with the DSPless
+	 * mode we are directly using the audio interface
+	 */
+	if (!sdev->dspless_mode_selected)
+		pd->be_hw_params_fixup = sof_pcm_dai_link_fixup;
 }

sound/soc/sof/pm.c

@@ -103,6 +103,11 @@ static int sof_resume(struct device *dev, bool runtime_resume)
 		return ret;
 	}
 
+	if (sdev->dspless_mode_selected) {
+		sof_set_fw_state(sdev, SOF_DSPLESS_MODE);
+		return 0;
+	}
+
 	/*
 	 * Nothing further to be done for platforms that support the low power
 	 * D0 substate. Resume trace and return when resuming from

sound/soc/sof/sof-audio.c

@@ -688,7 +688,7 @@ int sof_widget_list_setup(struct snd_sof_dev *sdev, struct snd_sof_pcm *spcm,
 		struct snd_sof_widget *pipe_widget;
 		struct snd_sof_pipeline *spipe;
 
-		if (!swidget)
+		if (!swidget || sdev->dspless_mode_selected)
 			continue;
 
 		spipe = swidget->spipe;

sound/soc/sof/sof-client.c

@@ -130,6 +130,9 @@ int sof_register_clients(struct snd_sof_dev *sdev)
 {
 	int ret;
 
+	if (sdev->dspless_mode_selected)
+		return 0;
+
 	/* Register platform independent client devices */
 	ret = sof_register_ipc_flood_test(sdev);
 	if (ret) {

sound/soc/sof/topology.c

@@ -1144,8 +1144,12 @@ static void sof_disconnect_dai_widget(struct snd_soc_component *scomp,
 static int spcm_bind(struct snd_soc_component *scomp, struct snd_sof_pcm *spcm,
 		     int dir)
 {
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
 	struct snd_sof_widget *host_widget;
 
+	if (sdev->dspless_mode_selected)
+		return 0;
+
 	host_widget = snd_sof_find_swidget_sname(scomp,
 						 spcm->pcm.caps[dir].name,
 						 dir);
@@ -2270,6 +2274,126 @@ static struct snd_soc_tplg_ops sof_tplg_ops = {
 	.bytes_ext_ops_count	= ARRAY_SIZE(sof_bytes_ext_ops),
 };
 
+static int snd_sof_dspless_kcontrol(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	return 0;
+}
+
+static const struct snd_soc_tplg_kcontrol_ops sof_dspless_io_ops[] = {
+	{SOF_TPLG_KCTL_VOL_ID, snd_sof_dspless_kcontrol, snd_sof_dspless_kcontrol},
+	{SOF_TPLG_KCTL_BYTES_ID, snd_sof_dspless_kcontrol, snd_sof_dspless_kcontrol},
+	{SOF_TPLG_KCTL_ENUM_ID, snd_sof_dspless_kcontrol, snd_sof_dspless_kcontrol},
+	{SOF_TPLG_KCTL_SWITCH_ID, snd_sof_dspless_kcontrol, snd_sof_dspless_kcontrol},
+};
+
+static int snd_sof_dspless_bytes_ext_get(struct snd_kcontrol *kcontrol,
+					 unsigned int __user *binary_data,
+					 unsigned int size)
+{
+	return 0;
+}
+
+static int snd_sof_dspless_bytes_ext_put(struct snd_kcontrol *kcontrol,
+					 const unsigned int __user *binary_data,
+					 unsigned int size)
+{
+	return 0;
+}
+
+static const struct snd_soc_tplg_bytes_ext_ops sof_dspless_bytes_ext_ops[] = {
+	{SOF_TPLG_KCTL_BYTES_ID, snd_sof_dspless_bytes_ext_get, snd_sof_dspless_bytes_ext_put},
+	{SOF_TPLG_KCTL_BYTES_VOLATILE_RO, snd_sof_dspless_bytes_ext_get},
+};
+
+/* external widget init - used for any driver specific init */
+static int sof_dspless_widget_ready(struct snd_soc_component *scomp, int index,
+				    struct snd_soc_dapm_widget *w,
+				    struct snd_soc_tplg_dapm_widget *tw)
+{
+	if (WIDGET_IS_DAI(w->id)) {
+		struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+		struct snd_sof_widget *swidget;
+		struct snd_sof_dai dai;
+		int ret;
+
+		swidget = kzalloc(sizeof(*swidget), GFP_KERNEL);
+		if (!swidget)
+			return -ENOMEM;
+
+		memset(&dai, 0, sizeof(dai));
+
+		ret = sof_connect_dai_widget(scomp, w, tw, &dai);
+		if (ret) {
+			kfree(swidget);
+			return ret;
+		}
+
+		swidget->scomp = scomp;
+		swidget->widget = w;
+		mutex_init(&swidget->setup_mutex);
+		w->dobj.private = swidget;
+		list_add(&swidget->list, &sdev->widget_list);
+	}
+
+	return 0;
+}
+
+static int sof_dspless_widget_unload(struct snd_soc_component *scomp,
+				     struct snd_soc_dobj *dobj)
+{
+	struct snd_soc_dapm_widget *w = container_of(dobj, struct snd_soc_dapm_widget, dobj);
+
+	if (WIDGET_IS_DAI(w->id)) {
+		struct snd_sof_widget *swidget = dobj->private;
+
+		sof_disconnect_dai_widget(scomp, w);
+
+		if (!swidget)
+			return 0;
+
+		/* remove and free swidget object */
+		list_del(&swidget->list);
+		kfree(swidget);
+	}
+
+	return 0;
+}
+
+static int sof_dspless_link_load(struct snd_soc_component *scomp, int index,
+				 struct snd_soc_dai_link *link,
+				 struct snd_soc_tplg_link_config *cfg)
+{
+	link->platforms->name = dev_name(scomp->dev);
+
+	/* Set nonatomic property for FE dai links for FE-BE compatibility */
+	if (!link->no_pcm)
+		link->nonatomic = true;
+
+	return 0;
+}
+
+static struct snd_soc_tplg_ops sof_dspless_tplg_ops = {
+	/* external widget init - used for any driver specific init */
+	.widget_ready	= sof_dspless_widget_ready,
+	.widget_unload	= sof_dspless_widget_unload,
+
+	/* FE DAI - used for any driver specific init */
+	.dai_load	= sof_dai_load,
+	.dai_unload	= sof_dai_unload,
+
+	/* DAI link - used for any driver specific init */
+	.link_load	= sof_dspless_link_load,
+
+	/* vendor specific kcontrol handlers available for binding */
+	.io_ops		= sof_dspless_io_ops,
+	.io_ops_count	= ARRAY_SIZE(sof_dspless_io_ops),
+
+	/* vendor specific bytes ext handlers available for binding */
+	.bytes_ext_ops = sof_dspless_bytes_ext_ops,
+	.bytes_ext_ops_count = ARRAY_SIZE(sof_dspless_bytes_ext_ops),
+};
+
 int snd_sof_load_topology(struct snd_soc_component *scomp, const char *file)
 {
 	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
@@ -2287,7 +2411,11 @@ int snd_sof_load_topology(struct snd_soc_component *scomp, const char *file)
 		return ret;
 	}
 
-	ret = snd_soc_tplg_component_load(scomp, &sof_tplg_ops, fw);
+	if (sdev->dspless_mode_selected)
+		ret = snd_soc_tplg_component_load(scomp, &sof_dspless_tplg_ops, fw);
+	else
+		ret = snd_soc_tplg_component_load(scomp, &sof_tplg_ops, fw);
+
 	if (ret < 0) {
 		dev_err(scomp->dev, "error: tplg component load failed %d\n",
 			ret);