ASoC: Intel: avs: Fix config_length for config-less copiers

Copier's config_length shall always be at least one even if there is no
configuration payload to carry. While the firmware treats
config_length=0 or 1 in the same manner, the driver shall initialize the
module properly.
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://msgid.link/r/20240405090929.1184068-5-cezary.rojewski@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/avs/path.c

@@ -148,11 +148,12 @@ static int avs_copier_create(struct avs_dev *adev, struct avs_path_module *mod)
 	struct avs_copier_cfg *cfg;
 	struct nhlt_specific_cfg *ep_blob;
 	union avs_connector_node_id node_id = {0};
-	size_t cfg_size, data_size = 0;
+	size_t cfg_size, data_size;
 	void *data = NULL;
 	u32 dma_type;
 	int ret;
 
+	data_size = sizeof(cfg->gtw_cfg.config);
 	dma_type = t->cfg_ext->copier.dma_type;
 	node_id.dma_type = dma_type;
 
@@ -233,10 +234,7 @@ static int avs_copier_create(struct avs_dev *adev, struct avs_path_module *mod)
 		break;
 	}
 
-	cfg_size = sizeof(*cfg) + data_size;
-	/* Every config-BLOB contains gateway attributes. */
-	if (data_size)
-		cfg_size -= sizeof(cfg->gtw_cfg.config.attrs);
+	cfg_size = offsetof(struct avs_copier_cfg, gtw_cfg.config) + data_size;
 	if (cfg_size > AVS_MAILBOX_SIZE)
 		return -EINVAL;