I'm trying to port GRBL 1.1 to the STM32F746 chip. Tell me the solution, thanks.

Revision:
0:f1834a63f7c1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usb/usb_desc.h	Mon Sep 04 12:03:42 2017 +0000
@@ -0,0 +1,53 @@
+/******************** (C) COPYRIGHT 2011 STMicroelectronics ********************
+* File Name          : usb_desc.h
+* Author             : MCD Application Team
+* Version            : V3.3.0
+* Date               : 21-March-2011
+* Description        : Descriptor Header for Virtual COM Port Device
+********************************************************************************
+* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
+* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
+* AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,
+* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
+* CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
+* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
+*******************************************************************************/
+
+/* Define to prevent recursive inclusion -------------------------------------*/
+#ifndef __USB_DESC_H
+#define __USB_DESC_H
+
+/* Includes ------------------------------------------------------------------*/
+/* Exported types ------------------------------------------------------------*/
+/* Exported constants --------------------------------------------------------*/
+/* Exported macro ------------------------------------------------------------*/
+/* Exported define -----------------------------------------------------------*/
+#define USB_DEVICE_DESCRIPTOR_TYPE              0x01
+#define USB_CONFIGURATION_DESCRIPTOR_TYPE       0x02
+#define USB_STRING_DESCRIPTOR_TYPE              0x03
+#define USB_INTERFACE_DESCRIPTOR_TYPE           0x04
+#define USB_ENDPOINT_DESCRIPTOR_TYPE            0x05
+
+#define VIRTUAL_COM_PORT_DATA_SIZE              64
+#define VIRTUAL_COM_PORT_INT_SIZE               8
+
+#define VIRTUAL_COM_PORT_SIZ_DEVICE_DESC        18
+#define VIRTUAL_COM_PORT_SIZ_CONFIG_DESC        67
+#define VIRTUAL_COM_PORT_SIZ_STRING_LANGID      4
+#define VIRTUAL_COM_PORT_SIZ_STRING_VENDOR      22
+#define VIRTUAL_COM_PORT_SIZ_STRING_PRODUCT     28
+#define VIRTUAL_COM_PORT_SIZ_STRING_SERIAL      26
+
+#define STANDARD_ENDPOINT_DESC_SIZE             0x09
+
+/* Exported functions ------------------------------------------------------- */
+extern const uint8_t Virtual_Com_Port_DeviceDescriptor[VIRTUAL_COM_PORT_SIZ_DEVICE_DESC];
+extern const uint8_t Virtual_Com_Port_ConfigDescriptor[VIRTUAL_COM_PORT_SIZ_CONFIG_DESC];
+
+extern const uint8_t Virtual_Com_Port_StringLangID[VIRTUAL_COM_PORT_SIZ_STRING_LANGID];
+extern const uint8_t Virtual_Com_Port_StringVendor[VIRTUAL_COM_PORT_SIZ_STRING_VENDOR];
+extern const uint8_t Virtual_Com_Port_StringProduct[VIRTUAL_COM_PORT_SIZ_STRING_PRODUCT];
+extern uint8_t Virtual_Com_Port_StringSerial[VIRTUAL_COM_PORT_SIZ_STRING_SERIAL];
+
+#endif /* __USB_DESC_H */
+/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/