ASoC: SOF: ipc4/Intel: Add support for library restore firmware functionality

The firmware will be able to only save and restore the context related to
library management.
This means that even without a full context save, the libraries do not
need to be re-loaded to the firmware after second or consecutive boots.

This is reported via the FW_READY notification, where BIT(15) indicates:
0 - the library restore is not done
1 - library restore is done

This bit is only valid if full context save is not enabled, full context
save is by definition saves and restores the library related book-keeping
as well.

Add a new flag to tell the platform code if the libraries have been
restored, no need to reload them after boot.

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

Author: ujfalusi

include/sound/sof/ipc4/header.h

@@ -502,6 +502,8 @@ struct sof_ipc4_intel_mic_privacy_cap {
 #define SOF_IPC4_LOG_CORE_GET(x)		(((x) & SOF_IPC4_LOG_CORE_MASK) >> \
 						 SOF_IPC4_LOG_CORE_SHIFT)
 
+#define SOF_IPC4_FW_READY_LIB_RESTORED		BIT(15)
+
 /* Value of notification type field - must fit into 8 bits */
 enum sof_ipc4_notification_type {
 	/* Phrase detected (notification from WoV module) */

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

@@ -579,8 +579,11 @@ int hda_dsp_ipc4_load_library(struct snd_sof_dev *sdev,
 	struct sof_ipc4_msg msg = {};
 	int ret, ret1;
 
-	/* if IMR booting is enabled and fw context is saved for D3 state, skip the loading */
-	if (reload && hda->booted_from_imr && ipc4_data->fw_context_save)
+	/*
+	 * if IMR booting is enabled and libraries have been restored during fw
+	 * boot, skip the loading
+	 */
+	if (reload && hda->booted_from_imr && ipc4_data->libraries_restored)
 		return 0;
 
 	/* the fw_lib has been verified during loading, we can trust the validity here */

sound/soc/sof/ipc4-priv.h

@@ -73,6 +73,7 @@ struct sof_ipc4_fw_library {
  * @max_libs_count: Maximum number of libraries support by the FW including the
  *		    base firmware
  * @fw_context_save: Firmware supports full context save and restore
+ * @libraries_restored: The libraries have been retained during firmware boot
  *
  * @load_library: Callback function for platform dependent library loading
  * @pipeline_state_mutex: Mutex to protect pipeline triggers, ref counts, states and deletion
@@ -88,6 +89,7 @@ struct sof_ipc4_fw_data {
 	int max_num_pipelines;
 	u32 max_libs_count;
 	bool fw_context_save;
+	bool libraries_restored;
 
 	int (*load_library)(struct snd_sof_dev *sdev,
 			    struct sof_ipc4_fw_library *fw_lib, bool reload);

sound/soc/sof/ipc4.c

@@ -602,8 +602,18 @@ EXPORT_SYMBOL(sof_ipc4_find_debug_slot_offset_by_type);
 static int ipc4_fw_ready(struct snd_sof_dev *sdev, struct sof_ipc4_msg *ipc4_msg)
 {
 	/* no need to re-check version/ABI for subsequent boots */
-	if (!sdev->first_boot)
+	if (!sdev->first_boot) {
+		struct sof_ipc4_fw_data *ipc4_data = sdev->private;
+
+		/*
+		 * The libraries have been restored if full context save is
+		 * enabled or the firmware reports this via the FW_READY
+		 */
+		ipc4_data->libraries_restored = ipc4_data->fw_context_save ||
+				(ipc4_msg->primary & SOF_IPC4_FW_READY_LIB_RESTORED);
+
 		return 0;
+	}
 
 	sof_ipc4_create_exception_debugfs_node(sdev);