ASoC: SOF: Fix runtime pm usage counter balance after fw exception

If the retain context is enabled we will unconditionally increment the
device's pm use count on each exception and when the drivers are unloaded
we do not correct this (as we don't know how many times we 'prevented
d3 entry').
Introduce a flag to make sure that we do not increment the use count more
than once and on module unload decrement the use count if needed to
balance it.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://msgid.link/r/20240213114729.7055-1-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/core.c

@@ -679,6 +679,16 @@ int snd_sof_device_remove(struct device *dev)
 	 */
 	snd_sof_machine_unregister(sdev, pdata);
 
+	/*
+	 * Balance the runtime pm usage count in case we are faced with an
+	 * exception and we forcably prevented D3 power state to preserve
+	 * context
+	 */
+	if (sdev->d3_prevented) {
+		sdev->d3_prevented = false;
+		pm_runtime_put_noidle(sdev->dev);
+	}
+
 	if (sdev->fw_state > SOF_FW_BOOT_NOT_STARTED) {
 		sof_fw_trace_free(sdev);
 		ret = snd_sof_dsp_power_down_notify(sdev);

sound/soc/sof/debug.c

@@ -433,13 +433,15 @@ static void snd_sof_ipc_dump(struct snd_sof_dev *sdev)
 
 void snd_sof_handle_fw_exception(struct snd_sof_dev *sdev, const char *msg)
 {
-	if (IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_RETAIN_DSP_CONTEXT) ||
-	    sof_debug_check_flag(SOF_DBG_RETAIN_CTX)) {
+	if ((IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_RETAIN_DSP_CONTEXT) ||
+	    sof_debug_check_flag(SOF_DBG_RETAIN_CTX)) && !sdev->d3_prevented) {
 		/* should we prevent DSP entering D3 ? */
 		if (!sdev->ipc_dump_printed)
 			dev_info(sdev->dev,
 				 "Attempting to prevent DSP from entering D3 state to preserve context\n");
-		pm_runtime_get_if_in_use(sdev->dev);
+
+		if (pm_runtime_get_if_in_use(sdev->dev) == 1)
+			sdev->d3_prevented = true;
 	}
 
 	/* dump vital information to the logs */

sound/soc/sof/sof-priv.h

@@ -595,6 +595,7 @@ struct snd_sof_dev {
 	struct list_head dfsentry_list;
 	bool dbg_dump_printed;
 	bool ipc_dump_printed;
+	bool d3_prevented; /* runtime pm use count incremented to prevent context lost */
 
 	/* firmware loader */
 	struct sof_ipc_fw_ready fw_ready;