Fixed the issue where the serialv2 terminal did not have the enable stream mode

Author: CYFS3

components/drivers/serial/dev_serial_v2.c

@@ -91,7 +91,6 @@ static int serial_fops_open(struct dfs_file *fd)
     if ((fd->flags & O_ACCMODE) != O_WRONLY)
         rt_device_set_rx_indicate(device, serial_fops_rx_ind);
 
-    rt_device_close(device);
     ret = rt_device_open(device, flags | RT_SERIAL_RX_BLOCKING | RT_SERIAL_TX_BLOCKING);
     if (ret == RT_EOK)
     {
@@ -1183,12 +1182,18 @@ static rt_err_t rt_serial_open(struct rt_device *dev, rt_uint16_t oflag)
 {
     struct rt_serial_device *serial;
     rt_err_t                 result = RT_EOK;
-
+    rt_uint16_t stream_flag = 0;
     RT_ASSERT(dev != RT_NULL);
     serial = (struct rt_serial_device *)dev;
 
     LOG_D("open serial device: 0x%08x with open flag: 0x%04x", dev, oflag);
+    
+    /* set steam flag */
+    if ((oflag & RT_DEVICE_FLAG_STREAM) || (dev->open_flag & RT_DEVICE_FLAG_STREAM))
+        stream_flag |= RT_DEVICE_FLAG_STREAM;
 
+    dev->open_flag = 0;
+    
     /* By default, the receive mode of a serial devide is RT_SERIAL_RX_NON_BLOCKING */
     if ((oflag & RT_SERIAL_RX_BLOCKING) == RT_SERIAL_RX_BLOCKING)
         dev->open_flag |= RT_SERIAL_RX_BLOCKING;
@@ -1201,9 +1206,7 @@ static rt_err_t rt_serial_open(struct rt_device *dev, rt_uint16_t oflag)
     else
         dev->open_flag |= RT_SERIAL_TX_BLOCKING;
 
-    /* set steam flag */
-    if ((oflag & RT_DEVICE_FLAG_STREAM) || (dev->open_flag & RT_DEVICE_FLAG_STREAM))
-        dev->open_flag |= RT_DEVICE_FLAG_STREAM;
+    dev->open_flag |= stream_flag;
 
     /* initialize the Rx structure according to open flag */
     if (serial->serial_rx == RT_NULL)