ASoC: SOF: Intel/ipc4: Support for low power playback

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

The following series will enable the the Low Power Audio (LPA)
playback on Intel platforms when using IPC4.

The support is closely follows how IPC3 supports similar use case.

All depending patches are upstream and our CI have been testing
this feature for some time without issues.

sound/soc/sof/intel/cnl.c

@@ -280,6 +280,8 @@ int cnl_ipc4_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg)
 	snd_sof_dsp_write(sdev, HDA_DSP_BAR, CNL_DSP_REG_HIPCIDR,
 			  msg_data->primary | CNL_DSP_REG_HIPCIDR_BUSY);
 
+	hda_dsp_ipc4_schedule_d0i3_work(hdev, msg);
+
 	return 0;
 }
 

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

@@ -364,19 +364,12 @@ static int hda_dsp_wait_d0i3c_done(struct snd_sof_dev *sdev)
 
 static int hda_dsp_send_pm_gate_ipc(struct snd_sof_dev *sdev, u32 flags)
 {
-	struct sof_ipc_pm_gate pm_gate;
-	struct sof_ipc_reply reply;
+	const struct sof_ipc_pm_ops *pm_ops = sof_ipc_get_ops(sdev, pm);
 
-	memset(&pm_gate, 0, sizeof(pm_gate));
+	if (pm_ops && pm_ops->set_pm_gate)
+		return pm_ops->set_pm_gate(sdev, flags);
 
-	/* configure pm_gate ipc message */
-	pm_gate.hdr.size = sizeof(pm_gate);
-	pm_gate.hdr.cmd = SOF_IPC_GLB_PM_MSG | SOF_IPC_PM_GATE;
-	pm_gate.flags = flags;
-
-	/* send pm_gate ipc to dsp */
-	return sof_ipc_tx_message_no_pm(sdev->ipc, &pm_gate, sizeof(pm_gate),
-					&reply, sizeof(reply));
+	return 0;
 }
 
 static int hda_dsp_update_d0i3c_register(struct snd_sof_dev *sdev, u8 value)
@@ -412,6 +405,34 @@ static int hda_dsp_update_d0i3c_register(struct snd_sof_dev *sdev, u8 value)
 	return 0;
 }
 
+/*
+ * d0i3 streaming is enabled if all the active streams can
+ * work in d0i3 state and playback is enabled
+ */
+static bool hda_dsp_d0i3_streaming_applicable(struct snd_sof_dev *sdev)
+{
+	struct snd_pcm_substream *substream;
+	struct snd_sof_pcm *spcm;
+	bool playback_active = false;
+	int dir;
+
+	list_for_each_entry(spcm, &sdev->pcm_list, list) {
+		for_each_pcm_streams(dir) {
+			substream = spcm->stream[dir].substream;
+			if (!substream || !substream->runtime)
+				continue;
+
+			if (!spcm->stream[dir].d0i3_compatible)
+				return false;
+
+			if (dir == SNDRV_PCM_STREAM_PLAYBACK)
+				playback_active = true;
+		}
+	}
+
+	return playback_active;
+}
+
 static int hda_dsp_set_D0_state(struct snd_sof_dev *sdev,
 				const struct sof_dsp_power_state *target_state)
 {
@@ -453,6 +474,9 @@ static int hda_dsp_set_D0_state(struct snd_sof_dev *sdev,
 		    !hda_enable_trace_D0I3_S0 ||
 		    sdev->system_suspend_target != SOF_SUSPEND_NONE)
 			flags = HDA_PM_NO_DMA_TRACE;
+
+		if (hda_dsp_d0i3_streaming_applicable(sdev))
+			flags |= HDA_PM_PG_STREAMING;
 	} else {
 		/* prevent power gating in D0I0 */
 		flags = HDA_PM_PPG;

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

@@ -67,6 +67,32 @@ int hda_dsp_ipc_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg)
 	return 0;
 }
 
+static inline bool hda_dsp_ipc4_pm_msg(u32 primary)
+{
+	/* pm setting is only supported by module msg */
+	if (SOF_IPC4_MSG_IS_MODULE_MSG(primary) != SOF_IPC4_MODULE_MSG)
+		return false;
+
+	if (SOF_IPC4_MSG_TYPE_GET(primary) == SOF_IPC4_MOD_SET_DX ||
+	    SOF_IPC4_MSG_TYPE_GET(primary) == SOF_IPC4_MOD_SET_D0IX)
+		return true;
+
+	return false;
+}
+
+void hda_dsp_ipc4_schedule_d0i3_work(struct sof_intel_hda_dev *hdev,
+				     struct snd_sof_ipc_msg *msg)
+{
+	struct sof_ipc4_msg *msg_data = msg->msg_data;
+
+	/* Schedule a delayed work for d0i3 entry after sending non-pm ipc msg */
+	if (hda_dsp_ipc4_pm_msg(msg_data->primary))
+		return;
+
+	mod_delayed_work(system_wq, &hdev->d0i3_work,
+			 msecs_to_jiffies(SOF_HDA_D0I3_WORK_DELAY_MS));
+}
+
 int hda_dsp_ipc4_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg)
 {
 	struct sof_intel_hda_dev *hdev = sdev->pdata->hw_pdata;
@@ -88,6 +114,8 @@ int hda_dsp_ipc4_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg)
 	snd_sof_dsp_write(sdev, HDA_DSP_BAR, HDA_DSP_REG_HIPCI,
 			  msg_data->primary | HDA_DSP_REG_HIPCI_BUSY);
 
+	hda_dsp_ipc4_schedule_d0i3_work(hdev, msg);
+
 	return 0;
 }
 

sound/soc/sof/intel/hda.h

@@ -919,6 +919,8 @@ irqreturn_t cnl_ipc4_irq_thread(int irq, void *context);
 int cnl_ipc4_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg);
 irqreturn_t hda_dsp_ipc4_irq_thread(int irq, void *context);
 bool hda_ipc4_tx_is_busy(struct snd_sof_dev *sdev);
+void hda_dsp_ipc4_schedule_d0i3_work(struct sof_intel_hda_dev *hdev,
+				     struct snd_sof_ipc_msg *msg);
 int hda_dsp_ipc4_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg);
 void hda_ipc4_dump(struct snd_sof_dev *sdev);
 extern struct sdw_intel_ops sdw_callback;

sound/soc/sof/intel/mtl.c

@@ -110,6 +110,8 @@ static int mtl_ipc_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *ms
 	snd_sof_dsp_write(sdev, HDA_DSP_BAR, MTL_DSP_REG_HFIPCXIDR,
 			  msg_data->primary | MTL_DSP_REG_HFIPCXIDR_BUSY);
 
+	hda_dsp_ipc4_schedule_d0i3_work(hdev, msg);
+
 	return 0;
 }
 

sound/soc/sof/ipc3.c

@@ -1077,10 +1077,28 @@ static int sof_ipc3_ctx_restore(struct snd_sof_dev *sdev)
 	return sof_ipc3_ctx_ipc(sdev, SOF_IPC_PM_CTX_RESTORE);
 }
 
+static int sof_ipc3_set_pm_gate(struct snd_sof_dev *sdev, u32 flags)
+{
+	struct sof_ipc_pm_gate pm_gate;
+	struct sof_ipc_reply reply;
+
+	memset(&pm_gate, 0, sizeof(pm_gate));
+
+	/* configure pm_gate ipc message */
+	pm_gate.hdr.size = sizeof(pm_gate);
+	pm_gate.hdr.cmd = SOF_IPC_GLB_PM_MSG | SOF_IPC_PM_GATE;
+	pm_gate.flags = flags;
+
+	/* send pm_gate ipc to dsp */
+	return sof_ipc_tx_message_no_pm(sdev->ipc, &pm_gate, sizeof(pm_gate),
+					&reply, sizeof(reply));
+}
+
 static const struct sof_ipc_pm_ops ipc3_pm_ops = {
 	.ctx_save = sof_ipc3_ctx_save,
 	.ctx_restore = sof_ipc3_ctx_restore,
 	.set_core_state = sof_ipc3_set_core_state,
+	.set_pm_gate = sof_ipc3_set_pm_gate,
 };
 
 const struct sof_ipc_ops ipc3_ops = {

sound/soc/sof/ipc4.c

@@ -370,6 +370,17 @@ static int sof_ipc4_tx_msg(struct snd_sof_dev *sdev, void *msg_data, size_t msg_
 	if (!msg_data)
 		return -EINVAL;
 
+	if (!no_pm) {
+		const struct sof_dsp_power_state target_state = {
+			.state = SOF_DSP_PM_D0,
+		};
+
+		/* ensure the DSP is in D0i0 before sending a new IPC */
+		ret = snd_sof_dsp_set_power_state(sdev, &target_state);
+		if (ret < 0)
+			return ret;
+	}
+
 	/* Serialise IPC TX */
 	mutex_lock(&ipc->tx_mutex);
 
@@ -656,9 +667,22 @@ static int sof_ipc4_ctx_save(struct snd_sof_dev *sdev)
 	return sof_ipc4_set_core_state(sdev, SOF_DSP_PRIMARY_CORE, false);
 }
 
+static int sof_ipc4_set_pm_gate(struct snd_sof_dev *sdev, u32 flags)
+{
+	struct sof_ipc4_msg msg = {{0}};
+
+	msg.primary = SOF_IPC4_MSG_TYPE_SET(SOF_IPC4_MOD_SET_D0IX);
+	msg.primary |= SOF_IPC4_MSG_DIR(SOF_IPC4_MSG_REQUEST);
+	msg.primary |= SOF_IPC4_MSG_TARGET(SOF_IPC4_MODULE_MSG);
+	msg.extension = flags;
+
+	return sof_ipc4_tx_msg(sdev, &msg, 0, NULL, 0, true);
+}
+
 static const struct sof_ipc_pm_ops ipc4_pm_ops = {
 	.ctx_save = sof_ipc4_ctx_save,
 	.set_core_state = sof_ipc4_set_core_state,
+	.set_pm_gate = sof_ipc4_set_pm_gate,
 };
 
 static int sof_ipc4_init(struct snd_sof_dev *sdev)

sound/soc/sof/sof-priv.h

@@ -425,11 +425,13 @@ struct sof_ipc_fw_tracing_ops {
  * @ctx_save:		Optional function pointer for context save
  * @ctx_restore:	Optional function pointer for context restore
  * @set_core_state:	Optional function pointer for turning on/off a DSP core
+ * @set_pm_gate:	Optional function pointer for pm gate settings
  */
 struct sof_ipc_pm_ops {
 	int (*ctx_save)(struct snd_sof_dev *sdev);
 	int (*ctx_restore)(struct snd_sof_dev *sdev);
 	int (*set_core_state)(struct snd_sof_dev *sdev, int core_idx, bool on);
+	int (*set_pm_gate)(struct snd_sof_dev *sdev, u32 flags);
 };
 
 /**