ASoC: SOF: Add support for on-demand DSP boot

On system suspend / resume we always power up the DSP and boot the
firmware, which is not strictly needed as right after the firmware booted
up we power the DSP down again on suspend and we also power it down after
resume after some inactivity.

Out of caution, add a new platform descriptor flag to enable on-demand
DSP boot since this might not work without changes to platform code on
certain platforms.

With the on-demand dsp boot enabled we will not boot the DSP and firmware
up on system or rpm resume, just enable audio subsystem since audio IPs,
like HDA and SoundWire might be needed (codecs suspend/resume operation).
Only boot up the DSP during the first hw_params() call when the DSP is
really going to be needed.

In this way we can handle the audio related use cases:
normal audio use (rpm suspend/resume)
system suspend/resume without active audio
system suspend/resume with active audio
system suspend/resume without active audio, and audio start before the rpm
suspend timeout

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Author: ujfalusi

include/sound/sof.h

@@ -159,6 +159,9 @@ struct sof_dev_desc {
 	/* The platform supports DSPless mode */
 	bool dspless_mode_supported;
 
+	/* On demand DSP booting is possible on the platform */
+	bool on_demand_dsp_boot;
+
 	/* defaults paths for firmware, library and topology files */
 	const char *default_fw_path[SOF_IPC_TYPE_COUNT];
 	const char *default_lib_path[SOF_IPC_TYPE_COUNT];

sound/soc/sof/compress.c

@@ -195,6 +195,14 @@ static int sof_compr_set_params(struct snd_soc_component *component,
 	if (sizeof(*pcm) + ext_data_size > sdev->ipc->max_payload_size)
 		return -EINVAL;
 
+	/*
+	 * Make sure that the DSP is booted up, which might not be the
+	 * case if the on-demand DSP boot is used
+	 */
+	ret = snd_sof_boot_dsp_firmware(sdev);
+	if (ret)
+		return ret;
+
 	pcm = kzalloc(sizeof(*pcm) + ext_data_size, GFP_KERNEL);
 	if (!pcm)
 		return -ENOMEM;

sound/soc/sof/control.c

@@ -198,7 +198,12 @@ int snd_sof_bytes_ext_volatile_get(struct snd_kcontrol *kcontrol, unsigned int _
 		return ret;
 	}
 
-	ret = tplg_ops->control->bytes_ext_volatile_get(scontrol, binary_data, size);
+	/* Make sure the DSP/firmware is booted up */
+	ret = snd_sof_boot_dsp_firmware(sdev);
+	if (!ret)
+		ret = tplg_ops->control->bytes_ext_volatile_get(scontrol,
+								binary_data,
+								size);
 
 	pm_runtime_mark_last_busy(scomp->dev);
 	err = pm_runtime_put_autosuspend(scomp->dev);

sound/soc/sof/core.c

@@ -694,6 +694,7 @@ int snd_sof_device_probe(struct device *dev, struct snd_sof_pdata *plat_data)
 	mutex_init(&sdev->power_state_access);
 	mutex_init(&sdev->ipc_client_mutex);
 	mutex_init(&sdev->client_event_handler_mutex);
+	mutex_init(&sdev->dsp_fw_boot_mutex);
 
 	/* set default timeouts if none provided */
 	if (plat_data->desc->ipc_timeout == 0)

sound/soc/sof/debug.c

@@ -216,7 +216,12 @@ static int memory_info_update(struct snd_sof_dev *sdev, char *buf, size_t buff_s
 		goto error;
 	}
 
-	ret = sof_ipc_tx_message(sdev->ipc, &msg, msg.size, reply, SOF_IPC_MSG_MAX_SIZE);
+	/* Make sure the DSP/firmware is booted up */
+	ret = snd_sof_boot_dsp_firmware(sdev);
+	if (!ret)
+		ret = sof_ipc_tx_message(sdev->ipc, &msg, msg.size, reply,
+					 SOF_IPC_MSG_MAX_SIZE);
+
 	pm_runtime_mark_last_busy(sdev->dev);
 	pm_runtime_put_autosuspend(sdev->dev);
 	if (ret < 0 || reply->rhdr.error < 0) {

sound/soc/sof/ipc3-dtrace.c

@@ -171,7 +171,12 @@ static int ipc3_trace_update_filter(struct snd_sof_dev *sdev, int num_elems,
 		dev_err(sdev->dev, "enabling device failed: %d\n", ret);
 		goto error;
 	}
-	ret = sof_ipc_tx_message_no_reply(sdev->ipc, msg, msg->hdr.size);
+
+	/* Make sure the DSP/firmware is booted up */
+	ret = snd_sof_boot_dsp_firmware(sdev);
+	if (!ret)
+		ret = sof_ipc_tx_message_no_reply(sdev->ipc, msg, msg->hdr.size);
+
 	pm_runtime_mark_last_busy(sdev->dev);
 	pm_runtime_put_autosuspend(sdev->dev);
 

sound/soc/sof/pcm.c

@@ -137,6 +137,16 @@ static int sof_pcm_hw_params(struct snd_soc_component *component,
 
 	spcm_dbg(spcm, substream->stream, "Entry: hw_params\n");
 
+	if (!sdev->dspless_mode_selected) {
+		/*
+		 * Make sure that the DSP is booted up, which might not be the
+		 * case if the on-demand DSP boot is used
+		 */
+		ret = snd_sof_boot_dsp_firmware(sdev);
+		if (ret)
+			return ret;
+	}
+
 	/*
 	 * Handle repeated calls to hw_params() without free_pcm() in
 	 * between. At least ALSA OSS emulation depends on this.

sound/soc/sof/pm.c

@@ -70,67 +70,28 @@ static void sof_cache_debugfs(struct snd_sof_dev *sdev)
 }
 #endif
 
-static int sof_resume(struct device *dev, bool runtime_resume)
+int snd_sof_boot_dsp_firmware(struct snd_sof_dev *sdev)
 {
-	struct snd_sof_dev *sdev = dev_get_drvdata(dev);
 	const struct sof_ipc_pm_ops *pm_ops = sof_ipc_get_ops(sdev, pm);
 	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
-	u32 old_state = sdev->dsp_power_state.state;
 	int ret;
 
-	/* do nothing if dsp resume callbacks are not set */
-	if (!runtime_resume && !sof_ops(sdev)->resume)
-		return 0;
-
-	if (runtime_resume && !sof_ops(sdev)->runtime_resume)
-		return 0;
+	guard(mutex)(&sdev->dsp_fw_boot_mutex);
 
-	/* DSP was never successfully started, nothing to resume */
-	if (sdev->first_boot)
+	if (sdev->fw_state == SOF_FW_BOOT_COMPLETE) {
+		/* Firmware already booted, just return */
 		return 0;
-
-	/*
-	 * if the runtime_resume flag is set, call the runtime_resume routine
-	 * or else call the system resume routine
-	 */
-	if (runtime_resume)
-		ret = snd_sof_dsp_runtime_resume(sdev);
-	else
-		ret = snd_sof_dsp_resume(sdev);
-	if (ret < 0) {
-		dev_err(sdev->dev,
-			"error: failed to power up DSP after resume\n");
-		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
-	 * low-power D0 substate
-	 */
-	if (!runtime_resume && sof_ops(sdev)->set_power_state &&
-	    old_state == SOF_DSP_PM_D0) {
-		ret = sof_fw_trace_resume(sdev);
-		if (ret < 0)
-			/* non fatal */
-			dev_warn(sdev->dev,
-				 "failed to enable trace after resume %d\n", ret);
-		return 0;
-	}
+	dev_dbg(sdev->dev, "Booting DSP firmware\n");
 
 	sof_set_fw_state(sdev, SOF_FW_BOOT_PREPARE);
 
 	/* load the firmware */
 	ret = snd_sof_load_firmware(sdev, NULL);
 	if (ret < 0) {
-		dev_err(sdev->dev,
-			"error: failed to load DSP firmware after resume %d\n",
-			ret);
+		dev_err(sdev->dev, "%s: failed to load DSP firmware: %d\n",
+			__func__, ret);
 		sof_set_fw_state(sdev, SOF_FW_BOOT_FAILED);
 		return ret;
 	}
@@ -143,9 +104,8 @@ static int sof_resume(struct device *dev, bool runtime_resume)
 	 */
 	ret = snd_sof_run_firmware(sdev);
 	if (ret < 0) {
-		dev_err(sdev->dev,
-			"error: failed to boot DSP firmware after resume %d\n",
-			ret);
+		dev_err(sdev->dev, "%s: failed to boot DSP firmware: %d\n",
+			__func__, ret);
 		sof_set_fw_state(sdev, SOF_FW_BOOT_FAILED);
 		return ret;
 	}
@@ -154,16 +114,16 @@ static int sof_resume(struct device *dev, bool runtime_resume)
 	ret = sof_fw_trace_resume(sdev);
 	if (ret < 0) {
 		/* non fatal */
-		dev_warn(sdev->dev,
-			 "warning: failed to init trace after resume %d\n",
-			 ret);
+		dev_warn(sdev->dev, "%s: failed to resume trace: %d\n",
+			 __func__, ret);
 	}
 
 	/* restore pipelines */
 	if (tplg_ops && tplg_ops->set_up_all_pipelines) {
 		ret = tplg_ops->set_up_all_pipelines(sdev, false);
 		if (ret < 0) {
-			dev_err(sdev->dev, "Failed to restore pipeline after resume %d\n", ret);
+			dev_err(sdev->dev, "%s: failed to restore pipeline: %d\n",
+				__func__, ret);
 			goto setup_fail;
 		}
 	}
@@ -175,7 +135,8 @@ static int sof_resume(struct device *dev, bool runtime_resume)
 	if (pm_ops && pm_ops->ctx_restore) {
 		ret = pm_ops->ctx_restore(sdev);
 		if (ret < 0)
-			dev_err(sdev->dev, "ctx_restore IPC error during resume: %d\n", ret);
+			dev_err(sdev->dev, "%s: ctx_restore IPC failed: %d\n",
+				__func__, ret);
 	}
 
 setup_fail:
@@ -192,6 +153,67 @@ static int sof_resume(struct device *dev, bool runtime_resume)
 
 	return ret;
 }
+EXPORT_SYMBOL(snd_sof_boot_dsp_firmware);
+
+static int sof_resume(struct device *dev, bool runtime_resume)
+{
+	struct snd_sof_dev *sdev = dev_get_drvdata(dev);
+	u32 old_state = sdev->dsp_power_state.state;
+	int ret;
+
+	/* do nothing if dsp resume callbacks are not set */
+	if (!runtime_resume && !sof_ops(sdev)->resume)
+		return 0;
+
+	if (runtime_resume && !sof_ops(sdev)->runtime_resume)
+		return 0;
+
+	/* DSP was never successfully started, nothing to resume */
+	if (sdev->first_boot)
+		return 0;
+
+	/*
+	 * if the runtime_resume flag is set, call the runtime_resume routine
+	 * or else call the system resume routine
+	 */
+	if (runtime_resume)
+		ret = snd_sof_dsp_runtime_resume(sdev);
+	else
+		ret = snd_sof_dsp_resume(sdev);
+	if (ret < 0) {
+		dev_err(sdev->dev,
+			"error: failed to power up DSP after resume\n");
+		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
+	 * low-power D0 substate
+	 */
+	if (!runtime_resume && sof_ops(sdev)->set_power_state &&
+	    old_state == SOF_DSP_PM_D0) {
+		ret = sof_fw_trace_resume(sdev);
+		if (ret < 0)
+			/* non fatal */
+			dev_warn(sdev->dev,
+				 "failed to enable trace after resume %d\n", ret);
+		return 0;
+	}
+
+	if (sdev->pdata->desc->on_demand_dsp_boot) {
+		/* Only change the fw_state to PREPARE but skip booting */
+		sof_set_fw_state(sdev, SOF_FW_BOOT_PREPARE);
+		return 0;
+	}
+
+	return snd_sof_boot_dsp_firmware(sdev);
+}
 
 static int sof_suspend(struct device *dev, bool runtime_suspend)
 {
@@ -297,8 +319,12 @@ int snd_sof_dsp_power_down_notify(struct snd_sof_dev *sdev)
 {
 	const struct sof_ipc_pm_ops *pm_ops = sof_ipc_get_ops(sdev, pm);
 
-	/* Notify DSP of upcoming power down */
-	if (sof_ops(sdev)->remove && pm_ops && pm_ops->ctx_save)
+	/*
+	 * Notify DSP of upcoming power down only if the firmware has been
+	 * booted up
+	 */
+	if (sdev->fw_state == SOF_FW_BOOT_COMPLETE && sof_ops(sdev)->remove &&
+	    pm_ops && pm_ops->ctx_save)
 		return pm_ops->ctx_save(sdev);
 
 	return 0;

sound/soc/sof/sof-priv.h

@@ -591,6 +591,8 @@ struct snd_sof_dev {
 	wait_queue_head_t boot_wait;
 	enum sof_fw_state fw_state;
 	bool first_boot;
+	/* mutex to protect DSP firmware boot (except initial, probe time boot */
+	struct mutex dsp_fw_boot_mutex;
 
 	/* work queue in case the probe is implemented in two steps */
 	struct work_struct probe_work;
@@ -717,6 +719,7 @@ int snd_sof_suspend(struct device *dev);
 int snd_sof_dsp_power_down_notify(struct snd_sof_dev *sdev);
 int snd_sof_prepare(struct device *dev);
 void snd_sof_complete(struct device *dev);
+int snd_sof_boot_dsp_firmware(struct snd_sof_dev *sdev);
 
 void snd_sof_new_platform_drv(struct snd_sof_dev *sdev);