ASoC: SOF: ipc4/intel: Support for ChainDMA

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

On a platform when the DSP is in use, we cannot select individual links
to use or not use the DSP, it is either all or none.  On some audio
endpoint, like HDMI/DP, it is preferred to not use any processing in DSP
to reduce the latency and to allow bytestream pass-through (DTS, DD,
etc)

IPC4 introduces a new type of end-to-end connection within the DSP which
is using the host DMA and link DMA in a single buffer, working
back-to-back, passing the received data without looking at it or trying
to understand the format, content.

This mode reduces the latency and allows non PCM streams to be sent from
userspace.

The feature is enabled per PCM bases, signalled in topology.

include/sound/sof/ipc4/header.h

@@ -196,6 +196,35 @@ enum sof_ipc4_pipeline_state {
 #define SOF_IPC4_GLB_LOAD_LIBRARY_LIB_ID_SHIFT	16
 #define SOF_IPC4_GLB_LOAD_LIBRARY_LIB_ID(x)	((x) << SOF_IPC4_GLB_LOAD_LIBRARY_LIB_ID_SHIFT)
 
+/* chain dma ipc message */
+#define SOF_IPC4_GLB_CHAIN_DMA_HOST_ID_SHIFT	0
+#define SOF_IPC4_GLB_CHAIN_DMA_HOST_ID_MASK	GENMASK(4, 0)
+#define SOF_IPC4_GLB_CHAIN_DMA_HOST_ID(x)	(((x) << SOF_IPC4_GLB_CHAIN_DMA_HOST_ID_SHIFT) & \
+						 SOF_IPC4_GLB_CHAIN_DMA_HOST_ID_MASK)
+
+#define SOF_IPC4_GLB_CHAIN_DMA_LINK_ID_SHIFT	8
+#define SOF_IPC4_GLB_CHAIN_DMA_LINK_ID_MASK	GENMASK(12, 8)
+#define SOF_IPC4_GLB_CHAIN_DMA_LINK_ID(x)	(((x) << SOF_IPC4_GLB_CHAIN_DMA_LINK_ID_SHIFT) & \
+						 SOF_IPC4_GLB_CHAIN_DMA_LINK_ID_MASK)
+
+#define SOF_IPC4_GLB_CHAIN_DMA_ALLOCATE_SHIFT	16
+#define SOF_IPC4_GLB_CHAIN_DMA_ALLOCATE_MASK	BIT(16)
+#define SOF_IPC4_GLB_CHAIN_DMA_ALLOCATE(x)	(((x) & 1) << SOF_IPC4_GLB_CHAIN_DMA_ALLOCATE_SHIFT)
+
+#define SOF_IPC4_GLB_CHAIN_DMA_ENABLE_SHIFT	17
+#define SOF_IPC4_GLB_CHAIN_DMA_ENABLE_MASK	BIT(17)
+#define SOF_IPC4_GLB_CHAIN_DMA_ENABLE(x)	(((x) & 1) << SOF_IPC4_GLB_CHAIN_DMA_ENABLE_SHIFT)
+
+#define SOF_IPC4_GLB_CHAIN_DMA_SCS_SHIFT	18
+#define SOF_IPC4_GLB_CHAIN_DMA_SCS_MASK		BIT(18)
+#define SOF_IPC4_GLB_CHAIN_DMA_SCS(x)		(((x) & 1) << SOF_IPC4_GLB_CHAIN_DMA_SCS_SHIFT)
+
+#define SOF_IPC4_GLB_EXT_CHAIN_DMA_FIFO_SIZE_SHIFT 0
+#define SOF_IPC4_GLB_EXT_CHAIN_DMA_FIFO_SIZE_MASK  GENMASK(24, 0)
+#define SOF_IPC4_GLB_EXT_CHAIN_DMA_FIFO_SIZE(x)	   (((x) << \
+						     SOF_IPC4_GLB_EXT_CHAIN_DMA_FIFO_SIZE_SHIFT) & \
+						    SOF_IPC4_GLB_EXT_CHAIN_DMA_FIFO_SIZE_MASK)
+
 enum sof_ipc4_channel_config {
 	/* one channel only. */
 	SOF_IPC4_CHANNEL_CONFIG_MONO,

include/uapi/sound/sof/tokens.h

@@ -54,6 +54,7 @@
 #define SOF_TKN_SCHED_DYNAMIC_PIPELINE		206
 #define SOF_TKN_SCHED_LP_MODE			207
 #define SOF_TKN_SCHED_MEM_USAGE			208
+#define SOF_TKN_SCHED_USE_CHAIN_DMA		209
 
 /* volume */
 #define SOF_TKN_VOLUME_RAMP_STEP_TYPE		250

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

@@ -277,6 +277,15 @@ static const struct hda_dai_widget_dma_ops hda_ipc4_dma_ops = {
 	.post_trigger = hda_ipc4_post_trigger
 };
 
+static const struct hda_dai_widget_dma_ops hda_ipc4_chain_dma_ops = {
+	.get_hext_stream = hda_get_hext_stream,
+	.assign_hext_stream = hda_assign_hext_stream,
+	.release_hext_stream = hda_release_hext_stream,
+	.setup_hext_stream = hda_setup_hext_stream,
+	.reset_hext_stream = hda_reset_hext_stream,
+	.trigger = hda_trigger,
+};
+
 static int hda_ipc3_post_trigger(struct snd_sof_dev *sdev, struct snd_soc_dai *cpu_dai,
 				 struct snd_pcm_substream *substream, int cmd)
 {
@@ -331,8 +340,15 @@ hda_select_dai_widget_ops(struct snd_sof_dev *sdev, struct snd_sof_widget *swidg
 	{
 		struct sof_ipc4_copier *ipc4_copier = sdai->private;
 
-		if (ipc4_copier->dai_type == SOF_DAI_INTEL_HDA)
+		if (ipc4_copier->dai_type == SOF_DAI_INTEL_HDA) {
+			struct snd_sof_widget *pipe_widget = swidget->spipe->pipe_widget;
+			struct sof_ipc4_pipeline *pipeline = pipe_widget->private;
+
+			if (pipeline->use_chain_dma)
+				return &hda_ipc4_chain_dma_ops;
+
 			return &hda_ipc4_dma_ops;
+		}
 		break;
 	}
 	default:

sound/soc/sof/ipc4-pcm.c

@@ -193,6 +193,88 @@ sof_ipc4_update_pipeline_state(struct snd_sof_dev *sdev, int state, int cmd,
  * prepare ioctl before the START trigger.
  */
 
+/*
+ * Chained DMA is a special case where there is no processing on
+ * DSP. The samples are just moved over by host side DMA to a single
+ * buffer on DSP and directly from there to link DMA. However, the
+ * model on SOF driver has two notional pipelines, one at host DAI,
+ * and another at link DAI. They both shall have the use_chain_dma
+ * attribute.
+ */
+
+static int sof_ipc4_chain_dma_trigger(struct snd_sof_dev *sdev,
+				      struct snd_sof_pcm_stream_pipeline_list *pipeline_list,
+				      int state, int cmd)
+{
+	bool allocate, enable, set_fifo_size;
+	struct sof_ipc4_msg msg = {{ 0 }};
+	int i;
+
+	switch (state) {
+	case SOF_IPC4_PIPE_RUNNING: /* Allocate and start chained dma */
+		allocate = true;
+		enable = true;
+		/*
+		 * SOF assumes creation of a new stream from the presence of fifo_size
+		 * in the message, so we must leave it out in pause release case.
+		 */
+		if (cmd == SNDRV_PCM_TRIGGER_PAUSE_RELEASE)
+			set_fifo_size = false;
+		else
+			set_fifo_size = true;
+		break;
+	case SOF_IPC4_PIPE_PAUSED: /* Disable chained DMA. */
+		allocate = true;
+		enable = false;
+		set_fifo_size = false;
+		break;
+	case SOF_IPC4_PIPE_RESET: /* Disable and free chained DMA. */
+		allocate = false;
+		enable = false;
+		set_fifo_size = false;
+		break;
+	default:
+		dev_err(sdev->dev, "Unexpected state %d", state);
+		return -EINVAL;
+	}
+
+	msg.primary = SOF_IPC4_MSG_TYPE_SET(SOF_IPC4_GLB_CHAIN_DMA);
+	msg.primary |= SOF_IPC4_MSG_DIR(SOF_IPC4_MSG_REQUEST);
+	msg.primary |= SOF_IPC4_MSG_TARGET(SOF_IPC4_FW_GEN_MSG);
+
+	/*
+	 * To set-up the DMA chain, the host DMA ID and SCS setting
+	 * are retrieved from the host pipeline configuration. Likewise
+	 * the link DMA ID and fifo_size are retrieved from the link
+	 * pipeline configuration.
+	 */
+	for (i = 0; i < pipeline_list->count; i++) {
+		struct snd_sof_pipeline *spipe = pipeline_list->pipelines[i];
+		struct snd_sof_widget *pipe_widget = spipe->pipe_widget;
+		struct sof_ipc4_pipeline *pipeline = pipe_widget->private;
+
+		if (!pipeline->use_chain_dma) {
+			dev_err(sdev->dev,
+				"All pipelines in chained DMA stream should have use_chain_dma attribute set.");
+			return -EINVAL;
+		}
+
+		msg.primary |= pipeline->msg.primary;
+
+		/* Add fifo_size (actually DMA buffer size) field to the message */
+		if (set_fifo_size)
+			msg.extension |= pipeline->msg.extension;
+	}
+
+	if (allocate)
+		msg.primary |= SOF_IPC4_GLB_CHAIN_DMA_ALLOCATE_MASK;
+
+	if (enable)
+		msg.primary |= SOF_IPC4_GLB_CHAIN_DMA_ENABLE_MASK;
+
+	return sof_ipc_tx_message(sdev->ipc, &msg, 0, NULL, 0);
+}
+
 static int sof_ipc4_trigger_pipelines(struct snd_soc_component *component,
 				      struct snd_pcm_substream *substream, int state, int cmd)
 {
@@ -201,6 +283,8 @@ static int sof_ipc4_trigger_pipelines(struct snd_soc_component *component,
 	struct snd_sof_pcm_stream_pipeline_list *pipeline_list;
 	struct sof_ipc4_fw_data *ipc4_data = sdev->private;
 	struct ipc4_pipeline_set_state_data *trigger_list;
+	struct snd_sof_widget *pipe_widget;
+	struct sof_ipc4_pipeline *pipeline;
 	struct snd_sof_pipeline *spipe;
 	struct snd_sof_pcm *spcm;
 	int ret;
@@ -218,6 +302,17 @@ static int sof_ipc4_trigger_pipelines(struct snd_soc_component *component,
 	if (!pipeline_list->pipelines || !pipeline_list->count)
 		return 0;
 
+	spipe = pipeline_list->pipelines[0];
+	pipe_widget = spipe->pipe_widget;
+	pipeline = pipe_widget->private;
+
+	/*
+	 * If use_chain_dma attribute is set we proceed to chained DMA
+	 * trigger function that handles the rest for the substream.
+	 */
+	if (pipeline->use_chain_dma)
+		return sof_ipc4_chain_dma_trigger(sdev, pipeline_list, state, cmd);
+
 	/* allocate memory for the pipeline data */
 	trigger_list = kzalloc(struct_size(trigger_list, pipeline_ids, pipeline_list->count),
 			       GFP_KERNEL);
@@ -422,8 +517,10 @@ static int sof_ipc4_pcm_dai_link_fixup(struct snd_soc_pcm_runtime *rtd,
 	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, SOF_AUDIO_PCM_DRV_NAME);
 	struct snd_sof_dai *dai = snd_sof_find_dai(component, rtd->dai_link->name);
 	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(component);
+	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0);
 	struct sof_ipc4_copier *ipc4_copier;
-	int ret;
+	bool use_chain_dma = false;
+	int dir;
 
 	if (!dai) {
 		dev_err(component->dev, "%s: No DAI found with name %s\n", __func__,
@@ -438,9 +535,26 @@ static int sof_ipc4_pcm_dai_link_fixup(struct snd_soc_pcm_runtime *rtd,
 		return -EINVAL;
 	}
 
-	ret = sof_ipc4_pcm_dai_link_fixup_rate(sdev, params, ipc4_copier);
-	if (ret)
-		return ret;
+	for_each_pcm_streams(dir) {
+		struct snd_soc_dapm_widget *w = snd_soc_dai_get_widget(cpu_dai, dir);
+
+		if (w) {
+			struct snd_sof_widget *swidget = w->dobj.private;
+			struct snd_sof_widget *pipe_widget = swidget->spipe->pipe_widget;
+			struct sof_ipc4_pipeline *pipeline = pipe_widget->private;
+
+			if (pipeline->use_chain_dma)
+				use_chain_dma = true;
+		}
+	}
+
+	/* Chain DMA does not use copiers, so no fixup needed */
+	if (!use_chain_dma) {
+		int ret = sof_ipc4_pcm_dai_link_fixup_rate(sdev, params, ipc4_copier);
+
+		if (ret)
+			return ret;
+	}
 
 	switch (ipc4_copier->dai_type) {
 	case SOF_DAI_INTEL_SSP: