ASoC: SOF: hda/ptl: Move mic privacy change notification sending to a work

IPC message cannot be sent from the irq thread directly as the message will
not receive the reply (interrupts are disabled) and it will time out - the
reply is going to be received right after the we leave the irq thread.
This is a different case compared to the delayed IPC messages due to DSP
busy state.

Add support for sending the mic privacy change notification to the firmware
from a work instead of the process callback.

The work needs to be canceled if there is a chance that it might be running
on module remove or before system/runtime suspend.

Fixes: 4a43c32 ("ASoC: SOF: Intel: ptl: Add support for mic privacy")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Author: ujfalusi

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

@@ -998,6 +998,10 @@ int hda_dsp_runtime_suspend(struct snd_sof_dev *sdev)
 	if (!sdev->dspless_mode_selected) {
 		/* cancel any attempt for DSP D0I3 */
 		cancel_delayed_work_sync(&hda->d0i3_work);
+
+		/* Cancel the microphone privacy work if mic privacy is active */
+		if (hda->mic_privacy.active)
+			cancel_work_sync(&hda->mic_privacy.work);
 	}
 
 	/* stop hda controller and power dsp off */
@@ -1020,6 +1024,10 @@ int hda_dsp_suspend(struct snd_sof_dev *sdev, u32 target_state)
 	if (!sdev->dspless_mode_selected) {
 		/* cancel any attempt for DSP D0I3 */
 		cancel_delayed_work_sync(&hda->d0i3_work);
+
+		/* Cancel the microphone privacy work if mic privacy is active */
+		if (hda->mic_privacy.active)
+			cancel_work_sync(&hda->mic_privacy.work);
 	}
 
 	if (target_state == SOF_DSP_PM_D0) {

sound/soc/sof/intel/hda.c

@@ -976,6 +976,10 @@ void hda_dsp_remove(struct snd_sof_dev *sdev)
 	if (sdev->dspless_mode_selected)
 		goto skip_disable_dsp;
 
+	/* Cancel the microphone privacy work if mic privacy is active */
+	if (hda->mic_privacy.active)
+		cancel_work_sync(&hda->mic_privacy.work);
+
 	/* no need to check for error as the DSP will be disabled anyway */
 	if (chip && chip->power_down_dsp)
 		chip->power_down_dsp(sdev);

sound/soc/sof/intel/hda.h

@@ -487,6 +487,11 @@ enum sof_hda_D0_substate {
 	SOF_HDA_DSP_PM_D0I3,	/* low power D0 substate */
 };
 
+struct sof_ace3_mic_privacy {
+	bool active;
+	struct work_struct work;
+};
+
 /* represents DSP HDA controller frontend - i.e. host facing control */
 struct sof_intel_hda_dev {
 	bool imrboot_supported;
@@ -542,6 +547,9 @@ struct sof_intel_hda_dev {
 	/* Intel NHLT information */
 	struct nhlt_acpi_table *nhlt;
 
+	/* work queue for mic privacy state change notification sending */
+	struct sof_ace3_mic_privacy mic_privacy;
+
 	/*
 	 * Pointing to the IPC message if immediate sending was not possible
 	 * because the downlink communication channel was BUSY at the time.

sound/soc/sof/intel/ptl.c

@@ -27,22 +27,44 @@ static bool sof_ptl_check_mic_privacy_irq(struct snd_sof_dev *sdev, bool alt,
 	return hdac_bus_eml_is_mic_privacy_changed(sof_to_bus(sdev), alt, elid);
 }
 
+static void sof_ptl_mic_privacy_work(struct work_struct *work)
+{
+	struct sof_intel_hda_dev *hdev = container_of(work,
+						      struct sof_intel_hda_dev,
+						      mic_privacy.work);
+	struct hdac_bus *bus = &hdev->hbus.core;
+	struct snd_sof_dev *sdev = dev_get_drvdata(bus->dev);
+	bool state;
+
+	/*
+	 * The microphone privacy state is only available via Soundwire shim
+	 * in PTL
+	 * The work is only scheduled on change.
+	 */
+	state = hdac_bus_eml_get_mic_privacy_state(bus, 1,
+						   AZX_REG_ML_LEPTR_ID_SDW);
+	sof_ipc4_mic_privacy_state_change(sdev, state);
+}
+
 static void sof_ptl_process_mic_privacy(struct snd_sof_dev *sdev, bool alt,
 					int elid)
 {
-	bool state;
+	struct sof_intel_hda_dev *hdev = sdev->pdata->hw_pdata;
 
 	if (!alt || elid != AZX_REG_ML_LEPTR_ID_SDW)
 		return;
 
-	state = hdac_bus_eml_get_mic_privacy_state(sof_to_bus(sdev), alt, elid);
-
-	sof_ipc4_mic_privacy_state_change(sdev, state);
+	/*
+	 * Schedule the work to read the microphone privacy state and send IPC
+	 * message about the new state to the firmware
+	 */
+	schedule_work(&hdev->mic_privacy.work);
 }
 
 static void sof_ptl_set_mic_privacy(struct snd_sof_dev *sdev,
 				    struct sof_ipc4_intel_mic_privacy_cap *caps)
 {
+	struct sof_intel_hda_dev *hdev = sdev->pdata->hw_pdata;
 	u32 micpvcp;
 
 	if (!caps || !caps->capabilities_length)
@@ -58,6 +80,9 @@ static void sof_ptl_set_mic_privacy(struct snd_sof_dev *sdev,
 	hdac_bus_eml_set_mic_privacy_mask(sof_to_bus(sdev), true,
 					  AZX_REG_ML_LEPTR_ID_SDW,
 					  PTL_MICPVCP_GET_SDW_MASK(micpvcp));
+
+	INIT_WORK(&hdev->mic_privacy.work, sof_ptl_mic_privacy_work);
+	hdev->mic_privacy.active = true;
 }
 
 int sof_ptl_set_ops(struct snd_sof_dev *sdev, struct snd_sof_dsp_ops *dsp_ops)