update(class/serial): add err log when rx overflow

Signed-off-by: sakumisu <1203593632@qq.com>

Author: sakumisu

class/serial/usbh_serial.c

@@ -73,6 +73,7 @@ static void usbh_serial_free(struct usbh_serial *serial)
 static void usbh_serial_callback(void *arg, int nbytes)
 {
     struct usbh_serial *serial = (struct usbh_serial *)arg;
+    uint32_t free_space;
     int ret;
 
     if (nbytes < 0) {
@@ -103,6 +104,11 @@ static void usbh_serial_callback(void *arg, int nbytes)
             return;
         }
 
+        free_space = usb_ringbuffer_get_free(&serial->rx_rb);
+        if (free_space < (nbytes - serial->driver->ignore_rx_header)) {
+            USB_LOG_ERR("serial rx ringbuffer overflow, free space: %u, rx size: %u\n", free_space, (nbytes - serial->driver->ignore_rx_header));
+        }
+
         usb_ringbuffer_write(&serial->rx_rb,
                              &serial->iobuffer[(serial->rx_buf_index ? USBH_SERIAL_RX2_NOCACHE_OFFSET : USBH_SERIAL_RX_NOCACHE_OFFSET) + serial->driver->ignore_rx_header],
                              (nbytes - serial->driver->ignore_rx_header));