ASoC: SOF: add mutex to protect the dsp_power_state access

There could be more than one thread read/write the dsp_power_state
simultaneously (e.g. hda_dsp_d0i3_work and sof_ipc_tx_message), add a
mutex power_state_access to make sure the access to it is mutually
exclusive.
Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Bard Liao <bard.liao@intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20210105155640.3725238-1-kai.vehmanen@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/core.c

@@ -316,6 +316,7 @@ int snd_sof_device_probe(struct device *dev, struct snd_sof_pdata *plat_data)
 	INIT_LIST_HEAD(&sdev->route_list);
 	spin_lock_init(&sdev->ipc_lock);
 	spin_lock_init(&sdev->hw_lock);
+	mutex_init(&sdev->power_state_access);
 
 	if (IS_ENABLED(CONFIG_SND_SOC_SOF_PROBE_WORK_QUEUE))
 		INIT_WORK(&sdev->probe_work, sof_probe_work);

sound/soc/sof/ops.h

@@ -208,11 +208,16 @@ static inline int
 snd_sof_dsp_set_power_state(struct snd_sof_dev *sdev,
 			    const struct sof_dsp_power_state *target_state)
 {
+	int ret = 0;
+
+	mutex_lock(&sdev->power_state_access);
+
 	if (sof_ops(sdev)->set_power_state)
-		return sof_ops(sdev)->set_power_state(sdev, target_state);
+		ret = sof_ops(sdev)->set_power_state(sdev, target_state);
 
-	/* D0 substate is not supported, do nothing here. */
-	return 0;
+	mutex_unlock(&sdev->power_state_access);
+
+	return ret;
 }
 
 /* debug */

sound/soc/sof/sof-priv.h

@@ -375,6 +375,8 @@ struct snd_sof_dev {
 
 	/* current DSP power state */
 	struct sof_dsp_power_state dsp_power_state;
+	/* mutex to protect the dsp_power_state access */
+	struct mutex power_state_access;
 
 	/* Intended power target of system suspend */
 	enum sof_system_suspend_state system_suspend_target;