Audio: DRC: Add processing enable switch control

This patch adds to DRC component in IPC4 mode a control to
switch processing on/off. The control is useful for DRC
pipeline that is used for both headphone (unprocessed) and
speaker (processed). It also allows the user to switch off
DRC processing if desired.

If a blob has enable set to false the processing cannot be
enabled with the switch control. If the blob enables processing,
the user space can control processing on or off.

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

src/audio/drc/drc.c

@@ -183,6 +183,13 @@ static int drc_init(struct processing_module *mod)
 	}
 
 	drc_reset_state(&cd->state);
+
+	/* Initialize DRC to enabled. If defined by topology, a control may set
+	 * enabled to false before prepare() or during streaming with the switch
+	 * control from user space.
+	 */
+	cd->enabled = true;
+	cd->enable_switch = true;
 	return 0;
 
 cd_fail:
@@ -202,15 +209,40 @@ static int drc_free(struct processing_module *mod)
 	return 0;
 }
 
-static int drc_set_config(struct processing_module *mod, uint32_t config_id,
+static int drc_set_config(struct processing_module *mod, uint32_t param_id,
 			  enum module_cfg_fragment_position pos, uint32_t data_offset_size,
 			  const uint8_t *fragment, size_t fragment_size, uint8_t *response,
 			  size_t response_size)
 {
 	struct drc_comp_data *cd = module_get_private_data(mod);
+	struct comp_dev *dev = mod->dev;
+
+	comp_dbg(dev, "drc_set_config()");
+
+#if CONFIG_IPC_MAJOR_4
+	struct sof_ipc4_control_msg_payload *ctl = (struct sof_ipc4_control_msg_payload *)fragment;
+
+	switch (param_id) {
+	case SOF_IPC4_SWITCH_CONTROL_PARAM_ID:
+		if (ctl->id == SOF_DRC_CTRL_INDEX_ENABLE_SWITCH &&
+		    ctl->num_elems == SOF_DRC_NUM_ELEMS_ENABLE_SWITCH) {
+			cd->enable_switch = ctl->chanv[0].value;
+			comp_info(dev, "drc_set_config(), enable_switch = %d", cd->enable_switch);
+		} else {
+			comp_err(dev, "Illegal switch control id = %d, num_elems = %d",
+				 ctl->id, ctl->num_elems);
+			return -EINVAL;
+		}
 
-	comp_info(mod->dev, "drc_set_config()");
+		return 0;
 
+	case SOF_IPC4_ENUM_CONTROL_PARAM_ID:
+		comp_err(dev, "drc_set_config(), illegal control.");
+		return -EINVAL;
+	}
+#endif
+
+	comp_info(dev, "drc_set_config(), bytes control");
 	return comp_data_blob_set(cd->model_handler, pos, data_offset_size, fragment,
 				  fragment_size);
 }
@@ -235,6 +267,11 @@ static void drc_set_alignment(struct audio_stream *source,
 	audio_stream_init_alignment_constants(1, 1, sink);
 }
 
+static bool drc_get_config_enabled(struct drc_comp_data *cd)
+{
+	return cd->config && cd->config->params.enabled;
+}
+
 static int drc_process(struct processing_module *mod,
 		       struct input_stream_buffer *input_buffers,
 		       int num_input_buffers,
@@ -261,6 +298,9 @@ static int drc_process(struct processing_module *mod,
 		}
 	}
 
+	/* Control pass-though in processing function with switch control */
+	cd->enabled = drc_get_config_enabled(cd) && cd->enable_switch;
+
 	cd->drc_func(mod, source, sink, frames);
 
 	/* calc new free and available */

src/audio/drc/drc_generic.c

@@ -543,7 +543,7 @@ static void drc_s16_default(struct processing_module *mod,
 	int fragment_samples;
 	int fragment;
 
-	if (!p->enabled) {
+	if (!cd->enabled) {
 		/* Delay the input sample only and don't do other processing. This is used when the
 		 * DRC is disabled. We want to do this to match the processing delay of other bands
 		 * in multi-band DRC kernel case.
@@ -689,7 +689,7 @@ static void drc_s24_default(struct processing_module *mod,
 	int fragment_samples;
 	int fragment;
 
-	if (!p->enabled) {
+	if (!cd->enabled) {
 		/* Delay the input sample only and don't do other processing. This is used when the
 		 * DRC is disabled. We want to do this to match the processing delay of other bands
 		 * in multi-band DRC kernel case. Note: use 32 bit delay function.
@@ -737,7 +737,7 @@ static void drc_s32_default(struct processing_module *mod,
 	int fragment_samples;
 	int fragment;
 
-	if (!p->enabled) {
+	if (!cd->enabled) {
 		/* Delay the input sample only and don't do other processing. This is used when the
 		 * DRC is disabled. We want to do this to match the processing delay of other bands
 		 * in multi-band DRC kernel case.

src/include/sof/audio/drc/drc.h

@@ -32,6 +32,12 @@ struct comp_dev;
 #define DRC_DIVISION_FRAMES 32
 #define DRC_DIVISION_FRAMES_MASK (DRC_DIVISION_FRAMES - 1)
 
+/* First switch control instance is zero (SOF_IPC4_SWITCH_CONTROL_PARAM_ID), and the
+ * control is common for all channels.
+ */
+#define SOF_DRC_CTRL_INDEX_ENABLE_SWITCH 0
+#define SOF_DRC_NUM_ELEMS_ENABLE_SWITCH 1
+
 /* Stores the state of DRC */
 struct drc_state {
 	/* The detector_average is the target gain obtained by looking at the
@@ -70,8 +76,10 @@ struct drc_comp_data {
 	struct comp_data_blob_handler *model_handler;
 	struct sof_drc_config *config;      /**< pointer to setup blob */
 	bool config_ready;                  /**< set when fully received */
+	bool enabled;                       /**< control processing via blob and switch */
+	bool enable_switch;                 /**< enable switch state */
 	enum sof_ipc_frame source_format;   /**< source frame format */
-	drc_func drc_func;            /**< processing function */
+	drc_func drc_func;                  /**< processing function */
 };
 
 struct drc_proc_fnmap {