From f58e947da6c451fd730bff9ac47130f85dd4a39c Mon Sep 17 00:00:00 2001
From: misonyo <misonyo@foxmail.com>
Date: Mon, 13 May 2019 15:52:20 +0800
Subject: [PATCH] [components/drivers/serial]add low level DMA TX config
 support.

---
 components/drivers/serial/serial.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index d4cf35414c..c3e96fc77b 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -675,6 +675,8 @@ static rt_err_t rt_serial_open(struct rt_device *dev, rt_uint16_t oflag)
             serial->serial_tx = tx_dma;
 
             dev->open_flag |= RT_DEVICE_FLAG_DMA_TX;
+            /* configure low level device */
+            serial->ops->control(serial, RT_DEVICE_CTRL_CONFIG, (void *)RT_DEVICE_FLAG_DMA_TX);
         }
 #endif /* RT_SERIAL_USING_DMA */
         else