ASoC: SOF: remove unregister calls from shutdown

Merge series from Kai Vehmanen <[email protected]>:

This patchset is an alternative solution to problems
reported by Ricardo Ribalda <[email protected]> and
Zhen Ni <[email protected]>, as discussed in

- "[PATCH] ALSA: core: Fix deadlock when shutdown a frozen userspace"
 https://mailman.alsa-project.org/pipermail/alsa-devel/2022-November/209248.html

- "[PATCH] ASoc: SOF: Fix sof-audio-pci-intel-tgl shutdown timeout during hibernation"
  https://mailman.alsa-project.org/pipermail/alsa-devel/2022-December/209685.html

It was raised by Oliver Neukum <[email protected]> that kernel should
not let user-space stall the shutdown process in any scenario and the
unregister call in current SOF shutdown code is not right.

This series reverts the ASoC SOF patch to unregister clients and
the machine drivers at shutdown. To avoid bringing back old bugs,
the series includes a patch to fix S5 entry on certain Intel
platforms.

Author: broonie

sound/soc/sof/core.c

@@ -475,19 +475,10 @@ EXPORT_SYMBOL(snd_sof_device_remove);
 int snd_sof_device_shutdown(struct device *dev)
 {
 	struct snd_sof_dev *sdev = dev_get_drvdata(dev);
-	struct snd_sof_pdata *pdata = sdev->pdata;
 
 	if (IS_ENABLED(CONFIG_SND_SOC_SOF_PROBE_WORK_QUEUE))
 		cancel_work_sync(&sdev->probe_work);
 
-	/*
-	 * make sure clients and machine driver(s) are unregistered to force
-	 * all userspace devices to be closed prior to the DSP shutdown sequence
-	 */
-	sof_unregister_clients(sdev);
-
-	snd_sof_machine_unregister(sdev, pdata);
-
 	if (sdev->fw_state == SOF_FW_BOOT_COMPLETE)
 		return snd_sof_shutdown(sdev);
 

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

@@ -878,6 +878,78 @@ int hda_dsp_suspend(struct snd_sof_dev *sdev, u32 target_state)
 	return snd_sof_dsp_set_power_state(sdev, &target_dsp_state);
 }
 
+static unsigned int hda_dsp_check_for_dma_streams(struct snd_sof_dev *sdev)
+{
+	struct hdac_bus *bus = sof_to_bus(sdev);
+	struct hdac_stream *s;
+	unsigned int active_streams = 0;
+	int sd_offset;
+	u32 val;
+
+	list_for_each_entry(s, &bus->stream_list, list) {
+		sd_offset = SOF_STREAM_SD_OFFSET(s);
+		val = snd_sof_dsp_read(sdev, HDA_DSP_HDA_BAR,
+				       sd_offset);
+		if (val & SOF_HDA_SD_CTL_DMA_START)
+			active_streams |= BIT(s->index);
+	}
+
+	return active_streams;
+}
+
+static int hda_dsp_s5_quirk(struct snd_sof_dev *sdev)
+{
+	int ret;
+
+	/*
+	 * Do not assume a certain timing between the prior
+	 * suspend flow, and running of this quirk function.
+	 * This is needed if the controller was just put
+	 * to reset before calling this function.
+	 */
+	usleep_range(500, 1000);
+
+	/*
+	 * Take controller out of reset to flush DMA
+	 * transactions.
+	 */
+	ret = hda_dsp_ctrl_link_reset(sdev, false);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(500, 1000);
+
+	/* Restore state for shutdown, back to reset */
+	ret = hda_dsp_ctrl_link_reset(sdev, true);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+int hda_dsp_shutdown_dma_flush(struct snd_sof_dev *sdev)
+{
+	unsigned int active_streams;
+	int ret, ret2;
+
+	/* check if DMA cleanup has been successful */
+	active_streams = hda_dsp_check_for_dma_streams(sdev);
+
+	sdev->system_suspend_target = SOF_SUSPEND_S3;
+	ret = snd_sof_suspend(sdev->dev);
+
+	if (active_streams) {
+		dev_warn(sdev->dev,
+			 "There were active DSP streams (%#x) at shutdown, trying to recover\n",
+			 active_streams);
+		ret2 = hda_dsp_s5_quirk(sdev);
+		if (ret2 < 0)
+			dev_err(sdev->dev, "shutdown recovery failed (%d)\n", ret2);
+	}
+
+	return ret;
+}
+
 int hda_dsp_shutdown(struct snd_sof_dev *sdev)
 {
 	sdev->system_suspend_target = SOF_SUSPEND_S3;

sound/soc/sof/intel/hda.h

@@ -592,6 +592,7 @@ int hda_dsp_resume(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_suspend(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_resume(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_idle(struct snd_sof_dev *sdev);
+int hda_dsp_shutdown_dma_flush(struct snd_sof_dev *sdev);
 int hda_dsp_shutdown(struct snd_sof_dev *sdev);
 int hda_dsp_set_hw_params_upon_resume(struct snd_sof_dev *sdev);
 void hda_dsp_dump(struct snd_sof_dev *sdev, u32 flags);

sound/soc/sof/intel/tgl.c

@@ -60,7 +60,7 @@ int sof_tgl_ops_init(struct snd_sof_dev *sdev)
 	memcpy(&sof_tgl_ops, &sof_hda_common_ops, sizeof(struct snd_sof_dsp_ops));
 
 	/* probe/remove/shutdown */
-	sof_tgl_ops.shutdown	= hda_dsp_shutdown;
+	sof_tgl_ops.shutdown	= hda_dsp_shutdown_dma_flush;
 
 	if (sdev->pdata->ipc_type == SOF_IPC) {
 		/* doorbell */