diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index 83a039bcf0..914054eb35 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -1,364 +1,379 @@
-/*
- * File      : serial.c
- * This file is part of RT-Thread RTOS
- * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
- *
- * The license and distribution terms for this file may be
- * found in the file LICENSE in this distribution or at
- * http://www.rt-thread.org/license/LICENSE
- *
- * Change Logs:
- * Date           Author       Notes
- * 2006-03-13     bernard      first version
- * 2012-05-15     lgnq         modified according bernard's implementation.
- * 2012-05-28     bernard      code cleanup
- */
-
-#include <rthw.h>
-#include <rtthread.h>
-#include <rtdevice.h>
-
-rt_inline void serial_ringbuffer_init(struct serial_ringbuffer *rbuffer)
-{
-	rt_memset(rbuffer->buffer, 0, sizeof(rbuffer->buffer));
-	rbuffer->put_index = 0;
-	rbuffer->get_index = 0;
-}
-
-rt_inline void serial_ringbuffer_putc(struct serial_ringbuffer *rbuffer, char ch)
-{
-	rt_base_t level;
-
-	/* disable interrupt */
-	level = rt_hw_interrupt_disable();
-
-	rbuffer->buffer[rbuffer->put_index] = ch;
-	rbuffer->put_index = (rbuffer->put_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
-
-	/* if the next position is read index, discard this 'read char' */
-	if (rbuffer->put_index == rbuffer->get_index)
-	{
-		rbuffer->get_index = (rbuffer->get_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
-	}
-
-	/* enable interrupt */
-	rt_hw_interrupt_enable(level);
-}
-
-rt_inline int serial_ringbuffer_putchar(struct serial_ringbuffer *rbuffer, char ch)
-{
-	rt_base_t level;
-	rt_uint16_t next_index;
-
-	/* disable interrupt */
-	level = rt_hw_interrupt_disable();
-
-	next_index = (rbuffer->put_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
-	if (next_index != rbuffer->get_index)
-	{
-		rbuffer->buffer[rbuffer->put_index] = ch;
-		rbuffer->put_index = next_index;
-	}
-	else
-	{
-		/* enable interrupt */
-		rt_hw_interrupt_enable(level);
-		return -1;
-	}
-
-	/* enable interrupt */
-	rt_hw_interrupt_enable(level);
-	return 1;
-}
-
-rt_inline int serial_ringbuffer_getc(struct serial_ringbuffer *rbuffer)
-{
-	int ch;
-	rt_base_t level;
-
-	ch = -1;
-	/* disable interrupt */
-	level = rt_hw_interrupt_disable();
-	if (rbuffer->get_index != rbuffer->put_index)
-	{
-		ch = rbuffer->buffer[rbuffer->get_index];
-		rbuffer->get_index = (rbuffer->get_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
-	}
-	/* enable interrupt */
-	rt_hw_interrupt_enable(level);
-	return ch;
-}
-
-rt_inline rt_uint32_t serial_ringbuffer_size(struct serial_ringbuffer *rbuffer)
-{
-	rt_uint32_t size;
-	rt_base_t level;
-
-	level = rt_hw_interrupt_disable();
-	size = (rbuffer->put_index - rbuffer->get_index) & (SERIAL_RBUFFER_SIZE - 1);
-	rt_hw_interrupt_enable(level);
-
-	return size;
-}
-
-/* RT-Thread Device Interface */
-
-/*
- * This function initializes serial
- */
-static rt_err_t rt_serial_init(struct rt_device *dev)
-{
-	rt_err_t result = RT_EOK;
-	struct rt_serial_device *serial;
-
-	RT_ASSERT(dev != RT_NULL);
-	serial = (struct rt_serial_device *)dev;
-
-	if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
-	{
-		/* apply configuration */
-		if (serial->ops->configure)
-			result = serial->ops->configure(serial, &serial->config);
-
-		if (result != RT_EOK)
-			return result;
-
-		if (dev->flag & RT_DEVICE_FLAG_INT_RX)
-			serial_ringbuffer_init(serial->int_rx);
-
-		if (dev->flag & RT_DEVICE_FLAG_INT_TX)
-			serial_ringbuffer_init(serial->int_tx);		 
-
-		/* set activated */
-		dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
-	}
-
-	return result;
-}
-
-static rt_err_t rt_serial_open(struct rt_device *dev, rt_uint16_t oflag)
-{
-	struct rt_serial_device *serial;
-	rt_uint32_t int_flags = 0;
-
-	RT_ASSERT(dev != RT_NULL);
-	serial = (struct rt_serial_device *)dev;
-
-	if (dev->flag & RT_DEVICE_FLAG_INT_RX)
-		int_flags = RT_SERIAL_RX_INT;
-	if (dev->flag & RT_DEVICE_FLAG_INT_TX)
-		int_flags |= RT_SERIAL_TX_INT;
-
-	if (int_flags)
-	{
-		serial->ops->control(serial, RT_DEVICE_CTRL_SET_INT, (void *)int_flags);
-	}
-
-	return RT_EOK;
-}
-
-static rt_err_t rt_serial_close(struct rt_device *dev)
-{
-	struct rt_serial_device *serial;
-	rt_uint32_t int_flags = 0;
-
-	RT_ASSERT(dev != RT_NULL);
-	serial = (struct rt_serial_device *)dev;
-
-	if (dev->flag & RT_DEVICE_FLAG_INT_RX)
-		int_flags = RT_SERIAL_RX_INT;
-	if (dev->flag & RT_DEVICE_FLAG_INT_TX)
-		int_flags |= RT_SERIAL_TX_INT;
-
-	if (int_flags)
-	{
-		serial->ops->control(serial, RT_DEVICE_CTRL_CLR_INT, (void *)int_flags);
-	}
-
-	return RT_EOK;
-}
-
-static rt_size_t rt_serial_read(struct rt_device *dev, rt_off_t pos, void *buffer, rt_size_t size)
-{
-	rt_uint8_t *ptr;
-	rt_uint32_t read_nbytes;
-	struct rt_serial_device *serial;
-
-	RT_ASSERT(dev != RT_NULL);
-	serial = (struct rt_serial_device *)dev;
-
-	ptr = (rt_uint8_t *)buffer;
-
-	if (dev->flag & RT_DEVICE_FLAG_INT_RX)
-	{
-		/* interrupt mode Rx */
-		while (size)
-		{
-			int ch;
-
-			ch = serial_ringbuffer_getc(serial->int_rx);
-			if (ch == -1)
-				break;
-
-			*ptr = ch & 0xff;
-			ptr ++;
-			size --;
-		}
-	}
-	else
-	{
-		/* polling mode */
-		while ((rt_uint32_t)ptr - (rt_uint32_t)buffer < size)
-		{
-			*ptr = serial->ops->getc(serial);
-			ptr ++;
-		}
-	}
-
-	read_nbytes = (rt_uint32_t)ptr - (rt_uint32_t)buffer;
-	/* set error code */
-	if (read_nbytes == 0)
-	{
-		rt_set_errno(-RT_EEMPTY);
-	}
-
-	return read_nbytes;
-}
-
-static rt_size_t rt_serial_write(struct rt_device *dev, rt_off_t pos,
-                                 const void *buffer, rt_size_t size)
-{
-	rt_uint8_t *ptr;
-	rt_size_t write_nbytes = 0;
-	struct rt_serial_device *serial;
-
-	RT_ASSERT(dev != RT_NULL);
-	serial = (struct rt_serial_device *)dev;
-
-	ptr = (rt_uint8_t*)buffer;
-
-	if (dev->flag & RT_DEVICE_FLAG_INT_TX)
-	{
-		/* warning: data will be discarded if buffer is full */
-		while (size)
-		{
-			if (serial_ringbuffer_putchar(serial->int_tx, *ptr) != -1)
-			{
-				ptr ++;
-				size --;
-			}
-			else
-				break;
-		}
-	}
-	else
-	{
-		/* polling mode */
-		while (size)
-		{
-			/*
-			 * to be polite with serial console add a line feed
-			 * to the carriage return character
-			 */
-			if (*ptr == '\n' && (dev->flag & RT_DEVICE_FLAG_STREAM))
-			{
-				serial->ops->putc(serial, '\r');
-			}
-
-			serial->ops->putc(serial, *ptr);
-
-			++ptr;
-			--size;
-		}
-	}
-
-	write_nbytes = (rt_uint32_t)ptr - (rt_uint32_t)buffer;
-	if (write_nbytes == 0)
-	{
-		rt_set_errno(-RT_EFULL);
-	}
-
-	return write_nbytes;
-}
-
-static rt_err_t rt_serial_control(struct rt_device *dev, rt_uint8_t cmd, void *args)
-{
-	struct rt_serial_device *serial;
-
-	RT_ASSERT(dev != RT_NULL);
-	serial = (struct rt_serial_device *)dev;
-
-	switch (cmd)
-	{
-	case RT_DEVICE_CTRL_SUSPEND:
-		/* suspend device */
-		dev->flag |= RT_DEVICE_FLAG_SUSPENDED;
-		break;
-
-	case RT_DEVICE_CTRL_RESUME:
-		/* resume device */
-		dev->flag &= ~RT_DEVICE_FLAG_SUSPENDED;
-		break;
-
-	case RT_DEVICE_CTRL_CONFIG:
-		/* configure device */
-		serial->ops->configure(serial, (struct serial_configure *)args);
-		break;
-	}
-
-	return RT_EOK;
-}
-
-/*
- * serial register
- */
-rt_err_t rt_hw_serial_register(struct rt_serial_device *serial, const char *name, rt_uint32_t flag, void *data)
-{
-	struct rt_device *device;
-	RT_ASSERT(serial != RT_NULL);
-
-	device = &(serial->parent);
-
-	device->type 		= RT_Device_Class_Char;
-	device->rx_indicate = RT_NULL;
-	device->tx_complete = RT_NULL;
-
-	device->init 		= rt_serial_init;
-	device->open		= rt_serial_open;
-	device->close		= rt_serial_close;
-	device->read 		= rt_serial_read;
-	device->write 		= rt_serial_write;
-	device->control 	= rt_serial_control;
-	device->user_data   = data;
-
-	/* register a character device */
-	return rt_device_register(device, name, flag);
-}
-
-/* ISR for serial interrupt */
-void rt_hw_serial_isr(struct rt_serial_device *serial)
-{
-	int ch = -1;
-
-	/* interrupt mode receive */
-	RT_ASSERT(serial->parent.flag & RT_DEVICE_FLAG_INT_RX);
-
-	while (1)
-	{
-		ch = serial->ops->getc(serial);
-		if (ch == -1)
-			break;
-
-		serial_ringbuffer_putc(serial->int_rx, ch);
-	}
-
-	/* invoke callback */
-	if (serial->parent.rx_indicate != RT_NULL)
-	{
-		rt_size_t rx_length;
-
-		/* get rx length */
-		rx_length = serial_ringbuffer_size(serial->int_rx);
-		serial->parent.rx_indicate(&serial->parent, rx_length);
-	}
-}
+/*
+ * File      : serial.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rt-thread.org/license/LICENSE
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2006-03-13     bernard      first version
+ * 2012-05-15     lgnq         modified according bernard's implementation.
+ * 2012-05-28     bernard      code cleanup
+ */
+
+#include <rthw.h>
+#include <rtthread.h>
+#include <rtdevice.h>
+
+rt_inline void serial_ringbuffer_init(struct serial_ringbuffer *rbuffer)
+{
+    rt_memset(rbuffer->buffer, 0, sizeof(rbuffer->buffer));
+    rbuffer->put_index = 0;
+    rbuffer->get_index = 0;
+}
+
+rt_inline void serial_ringbuffer_putc(struct serial_ringbuffer *rbuffer,
+                                      char                      ch)
+{
+    rt_base_t level;
+
+    /* disable interrupt */
+    level = rt_hw_interrupt_disable();
+
+    rbuffer->buffer[rbuffer->put_index] = ch;
+    rbuffer->put_index = (rbuffer->put_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+
+    /* if the next position is read index, discard this 'read char' */
+    if (rbuffer->put_index == rbuffer->get_index)
+    {
+        rbuffer->get_index = (rbuffer->get_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+    }
+
+    /* enable interrupt */
+    rt_hw_interrupt_enable(level);
+}
+
+rt_inline int serial_ringbuffer_putchar(struct serial_ringbuffer *rbuffer,
+                                        char                      ch)
+{
+    rt_base_t level;
+    rt_uint16_t next_index;
+
+    /* disable interrupt */
+    level = rt_hw_interrupt_disable();
+
+    next_index = (rbuffer->put_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+    if (next_index != rbuffer->get_index)
+    {
+        rbuffer->buffer[rbuffer->put_index] = ch;
+        rbuffer->put_index = next_index;
+    }
+    else
+    {
+        /* enable interrupt */
+        rt_hw_interrupt_enable(level);
+
+        return -1;
+    }
+
+    /* enable interrupt */
+    rt_hw_interrupt_enable(level);
+
+    return 1;
+}
+
+rt_inline int serial_ringbuffer_getc(struct serial_ringbuffer *rbuffer)
+{
+    int ch;
+    rt_base_t level;
+
+    ch = -1;
+    /* disable interrupt */
+    level = rt_hw_interrupt_disable();
+    if (rbuffer->get_index != rbuffer->put_index)
+    {
+        ch = rbuffer->buffer[rbuffer->get_index];
+        rbuffer->get_index = (rbuffer->get_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+    }
+    /* enable interrupt */
+    rt_hw_interrupt_enable(level);
+
+    return ch;
+}
+
+rt_inline rt_uint32_t serial_ringbuffer_size(struct serial_ringbuffer *rbuffer)
+{
+    rt_uint32_t size;
+    rt_base_t level;
+
+    level = rt_hw_interrupt_disable();
+    size = (rbuffer->put_index - rbuffer->get_index) & (SERIAL_RBUFFER_SIZE - 1);
+    rt_hw_interrupt_enable(level);
+
+    return size;
+}
+
+/* RT-Thread Device Interface */
+
+/*
+ * This function initializes serial
+ */
+static rt_err_t rt_serial_init(struct rt_device *dev)
+{
+    rt_err_t result = RT_EOK;
+    struct rt_serial_device *serial;
+
+    RT_ASSERT(dev != RT_NULL);
+    serial = (struct rt_serial_device *)dev;
+
+    if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
+    {
+        /* apply configuration */
+        if (serial->ops->configure)
+            result = serial->ops->configure(serial, &serial->config);
+
+        if (result != RT_EOK)
+            return result;
+
+        if (dev->flag & RT_DEVICE_FLAG_INT_RX)
+            serial_ringbuffer_init(serial->int_rx);
+
+        if (dev->flag & RT_DEVICE_FLAG_INT_TX)
+            serial_ringbuffer_init(serial->int_tx);      
+
+        /* set activated */
+        dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
+    }
+
+    return result;
+}
+
+static rt_err_t rt_serial_open(struct rt_device *dev, rt_uint16_t oflag)
+{
+    struct rt_serial_device *serial;
+    rt_uint32_t int_flags = 0;
+
+    RT_ASSERT(dev != RT_NULL);
+    serial = (struct rt_serial_device *)dev;
+
+    if (dev->flag & RT_DEVICE_FLAG_INT_RX)
+        int_flags = RT_SERIAL_RX_INT;
+    if (dev->flag & RT_DEVICE_FLAG_INT_TX)
+        int_flags |= RT_SERIAL_TX_INT;
+
+    if (int_flags)
+    {
+        serial->ops->control(serial, RT_DEVICE_CTRL_SET_INT, (void *)int_flags);
+    }
+
+    return RT_EOK;
+}
+
+static rt_err_t rt_serial_close(struct rt_device *dev)
+{
+    struct rt_serial_device *serial;
+    rt_uint32_t int_flags = 0;
+
+    RT_ASSERT(dev != RT_NULL);
+    serial = (struct rt_serial_device *)dev;
+
+    if (dev->flag & RT_DEVICE_FLAG_INT_RX)
+        int_flags = RT_SERIAL_RX_INT;
+    if (dev->flag & RT_DEVICE_FLAG_INT_TX)
+        int_flags |= RT_SERIAL_TX_INT;
+
+    if (int_flags)
+    {
+        serial->ops->control(serial, RT_DEVICE_CTRL_CLR_INT, (void *)int_flags);
+    }
+
+    return RT_EOK;
+}
+
+static rt_size_t rt_serial_read(struct rt_device *dev,
+                                rt_off_t          pos,
+                                void             *buffer,
+                                rt_size_t         size)
+{
+    rt_uint8_t *ptr;
+    rt_uint32_t read_nbytes;
+    struct rt_serial_device *serial;
+
+    RT_ASSERT(dev != RT_NULL);
+    serial = (struct rt_serial_device *)dev;
+
+    ptr = (rt_uint8_t *)buffer;
+
+    if (dev->flag & RT_DEVICE_FLAG_INT_RX)
+    {
+        /* interrupt mode Rx */
+        while (size)
+        {
+            int ch;
+
+            ch = serial_ringbuffer_getc(serial->int_rx);
+            if (ch == -1)
+                break;
+
+            *ptr = ch & 0xff;
+            ptr ++;
+            size --;
+        }
+    }
+    else
+    {
+        /* polling mode */
+        while ((rt_uint32_t)ptr - (rt_uint32_t)buffer < size)
+        {
+            *ptr = serial->ops->getc(serial);
+            ptr ++;
+        }
+    }
+
+    read_nbytes = (rt_uint32_t)ptr - (rt_uint32_t)buffer;
+    /* set error code */
+    if (read_nbytes == 0)
+    {
+        rt_set_errno(-RT_EEMPTY);
+    }
+
+    return read_nbytes;
+}
+
+static rt_size_t rt_serial_write(struct rt_device *dev,
+                                 rt_off_t          pos,
+                                 const void       *buffer,
+                                 rt_size_t         size)
+{
+    rt_uint8_t *ptr;
+    rt_size_t write_nbytes = 0;
+    struct rt_serial_device *serial;
+
+    RT_ASSERT(dev != RT_NULL);
+    serial = (struct rt_serial_device *)dev;
+
+    ptr = (rt_uint8_t*)buffer;
+
+    if (dev->flag & RT_DEVICE_FLAG_INT_TX)
+    {
+        /* warning: data will be discarded if buffer is full */
+        while (size)
+        {
+            if (serial_ringbuffer_putchar(serial->int_tx, *ptr) != -1)
+            {
+                ptr ++;
+                size --;
+            }
+            else
+                break;
+        }
+    }
+    else
+    {
+        /* polling mode */
+        while (size)
+        {
+            /*
+             * to be polite with serial console add a line feed
+             * to the carriage return character
+             */
+            if (*ptr == '\n' && (dev->flag & RT_DEVICE_FLAG_STREAM))
+            {
+                serial->ops->putc(serial, '\r');
+            }
+
+            serial->ops->putc(serial, *ptr);
+
+            ++ ptr;
+            -- size;
+        }
+    }
+
+    write_nbytes = (rt_uint32_t)ptr - (rt_uint32_t)buffer;
+    if (write_nbytes == 0)
+    {
+        rt_set_errno(-RT_EFULL);
+    }
+
+    return write_nbytes;
+}
+
+static rt_err_t rt_serial_control(struct rt_device *dev,
+                                  rt_uint8_t        cmd,
+                                  void             *args)
+{
+    struct rt_serial_device *serial;
+
+    RT_ASSERT(dev != RT_NULL);
+    serial = (struct rt_serial_device *)dev;
+
+    switch (cmd)
+    {
+    case RT_DEVICE_CTRL_SUSPEND:
+        /* suspend device */
+        dev->flag |= RT_DEVICE_FLAG_SUSPENDED;
+        break;
+
+    case RT_DEVICE_CTRL_RESUME:
+        /* resume device */
+        dev->flag &= ~RT_DEVICE_FLAG_SUSPENDED;
+        break;
+
+    case RT_DEVICE_CTRL_CONFIG:
+        /* configure device */
+        serial->ops->configure(serial, (struct serial_configure *)args);
+        break;
+    }
+
+    return RT_EOK;
+}
+
+/*
+ * serial register
+ */
+rt_err_t rt_hw_serial_register(struct rt_serial_device *serial,
+                               const char              *name,
+                               rt_uint32_t              flag,
+                               void                    *data)
+{
+    struct rt_device *device;
+    RT_ASSERT(serial != RT_NULL);
+
+    device = &(serial->parent);
+
+    device->type        = RT_Device_Class_Char;
+    device->rx_indicate = RT_NULL;
+    device->tx_complete = RT_NULL;
+
+    device->init        = rt_serial_init;
+    device->open        = rt_serial_open;
+    device->close       = rt_serial_close;
+    device->read        = rt_serial_read;
+    device->write       = rt_serial_write;
+    device->control     = rt_serial_control;
+    device->user_data   = data;
+
+    /* register a character device */
+    return rt_device_register(device, name, flag);
+}
+
+/* ISR for serial interrupt */
+void rt_hw_serial_isr(struct rt_serial_device *serial)
+{
+    int ch = -1;
+
+    /* interrupt mode receive */
+    RT_ASSERT(serial->parent.flag & RT_DEVICE_FLAG_INT_RX);
+
+    while (1)
+    {
+        ch = serial->ops->getc(serial);
+        if (ch == -1)
+            break;
+
+        serial_ringbuffer_putc(serial->int_rx, ch);
+    }
+
+    /* invoke callback */
+    if (serial->parent.rx_indicate != RT_NULL)
+    {
+        rt_size_t rx_length;
+
+        /* get rx length */
+        rx_length = serial_ringbuffer_size(serial->int_rx);
+        serial->parent.rx_indicate(&serial->parent, rx_length);
+    }
+}