usb: device_next: avoid false error logging in CDC ECM/NCM

The interface descriptor and its associated string descriptor are shared
between different speed configurations. Do not try to add a string
descriptor if it has already been added and the index is not zero.

Similar to commit ec851ba
("usb: device_next: avoid false error logging in CDC ACM").

Signed-off-by: Johann Fischer <[email protected]>

Author: jfischer-no

subsys/usb/device_next/class/usbd_cdc_ecm.c

@@ -455,10 +455,12 @@ static int usbd_cdc_ecm_init(struct usbd_class_data *const c_data)
 	desc->if0_union.bSubordinateInterface0 = if_num + 1;
 	LOG_DBG("CDC ECM class initialized");
 
-	if (usbd_add_descriptor(uds_ctx, data->mac_desc_data)) {
-		LOG_ERR("Failed to add iMACAddress string descriptor");
-	} else {
-		desc->if0_ecm.iMACAddress = usbd_str_desc_get_idx(data->mac_desc_data);
+	if (desc->if0_ecm.iMACAddress == 0) {
+		if (usbd_add_descriptor(uds_ctx, data->mac_desc_data)) {
+			LOG_ERR("Failed to add iMACAddress string descriptor");
+		} else {
+			desc->if0_ecm.iMACAddress = usbd_str_desc_get_idx(data->mac_desc_data);
+		}
 	}
 
 	return 0;

subsys/usb/device_next/class/usbd_cdc_ncm.c

@@ -989,10 +989,12 @@ static int usbd_cdc_ncm_init(struct usbd_class_data *const c_data)
 
 	LOG_DBG("CDC NCM class initialized");
 
-	if (usbd_add_descriptor(uds_ctx, data->mac_desc_data)) {
-		LOG_ERR("Failed to add iMACAddress string descriptor");
-	} else {
-		desc->if0_ecm.iMACAddress = usbd_str_desc_get_idx(data->mac_desc_data);
+	if (desc->if0_ecm.iMACAddress == 0) {
+		if (usbd_add_descriptor(uds_ctx, data->mac_desc_data)) {
+			LOG_ERR("Failed to add iMACAddress string descriptor");
+		} else {
+			desc->if0_ecm.iMACAddress = usbd_str_desc_get_idx(data->mac_desc_data);
+		}
 	}
 
 	return 0;
@@ -1243,7 +1245,7 @@ static struct usbd_cdc_ncm_desc cdc_ncm_desc_##n = {				\
 		.bFunctionLength = sizeof(struct cdc_ecm_descriptor),		\
 		.bDescriptorType = USB_DESC_CS_INTERFACE,			\
 		.bDescriptorSubtype = ETHERNET_FUNC_DESC,			\
-		.iMACAddress = 4,						\
+		.iMACAddress = 0,						\
 		.bmEthernetStatistics = sys_cpu_to_le32(0),			\
 		.wMaxSegmentSize = sys_cpu_to_le16(NET_ETH_MAX_FRAME_SIZE),	\
 		.wNumberMCFilters = sys_cpu_to_le16(0),				\