/*
 * File      : cdc_vcom.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2012, RT-Thread Development Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2012-10-02     Yi Qiu       first version
 * 2012-12-12     heyuanjie87  change endpoints and function handler 
 * 2013-06-25     heyuanjie87  remove SOF mechinism
 * 2013-07-20     Yi Qiu       do more test
 * 2016-02-01     Urey         Fix some error
 */

#include <rthw.h>
#include <rtthread.h>
#include <rtservice.h>
#include <rtdevice.h>
#include <drivers/serial.h>
#include "drivers/usb_device.h"
#include "cdc.h"

#ifdef RT_USB_DEVICE_CDC

#define TX_TIMEOUT              1000
#define CDC_RX_BUFSIZE          2048
#define CDC_MAX_PACKET_SIZE     64
#define VCOM_DEVICE             "vcom"

#define VCOM_TASK_STK_SIZE      2048

//#define VCOM_TX_USE_DMA

ALIGN(RT_ALIGN_SIZE)
static rt_uint8_t vcom_thread_stack[VCOM_TASK_STK_SIZE];
static struct rt_thread vcom_thread;
#define VCOM_MQ_MSG_SZ  16
#define VCOM_MQ_MAX_MSG 4
/* internal of the message queue: every message is associated with a pointer,
 * so in order to recveive VCOM_MQ_MAX_MSG messages, we have to allocate more
 * than VCOM_MQ_MSG_SZ*VCOM_MQ_MAX_MSG memery. */
static rt_uint8_t vcom_tx_thread_mq_pool[(VCOM_MQ_MSG_SZ+sizeof(void*))*VCOM_MQ_MAX_MSG];
static struct rt_messagequeue vcom_tx_thread_mq;
static struct ucdc_line_coding line_coding;

struct vcom
{
    struct rt_serial_device     serial;
    uep_t ep_out;
    uep_t ep_in;
    uep_t ep_cmd;
    rt_bool_t connected;
    rt_bool_t in_sending;
    struct rt_completion wait;
    rt_uint8_t rx_rbp[CDC_RX_BUFSIZE];    
    struct rt_ringbuffer rx_ringbuffer;   
};

struct vcom_tx_msg
{
    struct rt_serial_device * serial;
    const char *buf;
    rt_size_t size;
};

static struct udevice_descriptor dev_desc =
{
    USB_DESC_LENGTH_DEVICE,     //bLength;
    USB_DESC_TYPE_DEVICE,       //type;
    USB_BCD_VERSION,            //bcdUSB;
    USB_CLASS_CDC,              //bDeviceClass;
    0x00,                       //bDeviceSubClass;
    0x00,                       //bDeviceProtocol;
    CDC_MAX_PACKET_SIZE,          //bMaxPacketSize0;
    _VENDOR_ID,                 //idVendor;
    _PRODUCT_ID,                //idProduct;
    USB_BCD_DEVICE,             //bcdDevice;
    USB_STRING_MANU_INDEX,      //iManufacturer;
    USB_STRING_PRODUCT_INDEX,   //iProduct;
    USB_STRING_SERIAL_INDEX,    //iSerialNumber;
    USB_DYNAMIC,                //bNumConfigurations;
};

static struct usb_qualifier_descriptor dev_qualifier =
{
    sizeof(dev_qualifier),
    USB_DESC_TYPE_DEVICEQUALIFIER,
    0x0200,
    USB_CLASS_CDC,
    0x00,
    64,
    0x01,
    0,
};

/* communcation interface descriptor */
const static struct ucdc_comm_descriptor _comm_desc =
{
#ifdef RT_USB_DEVICE_COMPOSITE
    /* Interface Association Descriptor */
    USB_DESC_LENGTH_IAD,
    USB_DESC_TYPE_IAD,
    USB_DYNAMIC,
    0x02,
    USB_CDC_CLASS_COMM,
    USB_CDC_SUBCLASS_ACM,
    USB_CDC_PROTOCOL_V25TER,
    0x00,
#endif
    /* Interface Descriptor */
    USB_DESC_LENGTH_INTERFACE,
    USB_DESC_TYPE_INTERFACE,
    USB_DYNAMIC,
    0x00,   
    0x01,
    USB_CDC_CLASS_COMM,
    USB_CDC_SUBCLASS_ACM,
    USB_CDC_PROTOCOL_V25TER,
    0x00,
    /* Header Functional Descriptor */   
    0x05,                              
    USB_CDC_CS_INTERFACE,
    USB_CDC_SCS_HEADER,
    0x0110,
    /* Call Management Functional Descriptor */   
    0x05,            
    USB_CDC_CS_INTERFACE,
    USB_CDC_SCS_CALL_MGMT,
    0x00,
    USB_DYNAMIC,
    /* Abstract Control Management Functional Descriptor */
    0x04,
    USB_CDC_CS_INTERFACE,
    USB_CDC_SCS_ACM,
    0x02,
    /* Union Functional Descriptor */   
    0x05,
    USB_CDC_CS_INTERFACE,
    USB_CDC_SCS_UNION,
    USB_DYNAMIC,
    USB_DYNAMIC,
    /* Endpoint Descriptor */    
    USB_DESC_LENGTH_ENDPOINT,
    USB_DESC_TYPE_ENDPOINT,
    USB_DYNAMIC | USB_DIR_IN,
    USB_EP_ATTR_INT,
    0x08,
    0xFF,
};

/* data interface descriptor */
const static struct ucdc_data_descriptor _data_desc =
{
    /* interface descriptor */
    USB_DESC_LENGTH_INTERFACE,
    USB_DESC_TYPE_INTERFACE,
    USB_DYNAMIC,
    0x00,
    0x02,         
    USB_CDC_CLASS_DATA,
    0x00,                             
    0x00,                             
    0x00,              
    /* endpoint, bulk out */
    USB_DESC_LENGTH_ENDPOINT,     
    USB_DESC_TYPE_ENDPOINT,
    USB_DYNAMIC | USB_DIR_OUT,
    USB_EP_ATTR_BULK,      
    USB_CDC_BUFSIZE,
    0x00,          
    /* endpoint, bulk in */
    USB_DESC_LENGTH_ENDPOINT,
    USB_DESC_TYPE_ENDPOINT,
    USB_DYNAMIC | USB_DIR_IN,
    USB_EP_ATTR_BULK,      
    USB_CDC_BUFSIZE,
    0x00,
};

const static char* _ustring[] =
{
    "Language",
    "RT-Thread Team.",
    "RTT Virtual Serial",
    "32021919830108",
    "Configuration",
    "Interface",
};
static void rt_usb_vcom_init(struct ufunction *func);

static void _vcom_reset_state(ufunction_t func)
{
    struct vcom* data;
    int lvl;
    
    RT_ASSERT(func != RT_NULL)

    data = (struct vcom*)func->user_data;
    
    lvl = rt_hw_interrupt_disable();
    data->connected = RT_FALSE;
    data->in_sending = RT_FALSE;
    /*rt_kprintf("reset USB serial\n", cnt);*/
    rt_hw_interrupt_enable(lvl);
}

/**
 * This function will handle cdc bulk in endpoint request.
 *
 * @param func the usb function object.
 * @param size request size.
 *
 * @return RT_EOK.
 */
static rt_err_t _ep_in_handler(ufunction_t func, rt_size_t size)
{
    struct vcom *data;

    RT_ASSERT(func != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("_ep_in_handler %d\n", size));
    rt_kprintf("%s size = %d\n",__func__,size);
    data = (struct vcom*)func->user_data;
    if ((size != 0) && (size % CDC_MAX_PACKET_SIZE == 0))
    {
        /* don't have data right now. Send a zero-length-packet to
         * terminate the transaction.
         *
         * FIXME: actually, this might not be the right place to send zlp.
         * Only the rt_device_write could know how much data is sending. */
        data->in_sending = RT_TRUE;

        data->ep_in->request.buffer = RT_NULL;
        data->ep_in->request.size = 0;
        data->ep_in->request.req_type = UIO_REQUEST_WRITE;
        rt_usbd_io_request(func->device, data->ep_in, &data->ep_in->request);

        return RT_EOK;
    }
    
    rt_completion_done(&data->wait);
    
    return RT_EOK;
}

/**
 * This function will handle cdc bulk out endpoint request.
 *
 * @param func the usb function object.
 * @param size request size.
 *
 * @return RT_EOK.
 */
static rt_err_t _ep_out_handler(ufunction_t func, rt_size_t size)
{
    rt_uint32_t level;
    struct vcom *data;

    RT_ASSERT(func != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("_ep_out_handler %d\n", size));
    
    data = (struct vcom*)func->user_data;
    /* receive data from USB VCOM */
    level = rt_hw_interrupt_disable();

    rt_ringbuffer_put(&data->rx_ringbuffer, data->ep_out->buffer, size);
    rt_hw_interrupt_enable(level);

    /* notify receive data */
    rt_hw_serial_isr(&data->serial,RT_SERIAL_EVENT_RX_IND);

    data->ep_out->request.buffer = data->ep_out->buffer;
    data->ep_out->request.size = EP_MAXPACKET(data->ep_out);
    data->ep_out->request.req_type = UIO_REQUEST_READ_BEST;    
    rt_usbd_io_request(func->device, data->ep_out, &data->ep_out->request);

    return RT_EOK;
}

/**
 * This function will handle cdc interrupt in endpoint request.
 *
 * @param device the usb device object.
 * @param size request size.
 *
 * @return RT_EOK.
 */
static rt_err_t _ep_cmd_handler(ufunction_t func, rt_size_t size)
{
    RT_ASSERT(func != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("_ep_cmd_handler\n"));

    return RT_EOK;
}

/**
 * This function will handle cdc_get_line_coding request.
 *
 * @param device the usb device object.
 * @param setup the setup request.
 *
 * @return RT_EOK on successful.
 */
static rt_err_t _cdc_get_line_coding(udevice_t device, ureq_t setup)
{
    struct ucdc_line_coding data;
    rt_uint16_t size;

    RT_ASSERT(device != RT_NULL);
    RT_ASSERT(setup != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("_cdc_get_line_coding\n"));

    data.dwDTERate = 115200;
    data.bCharFormat = 0;
    data.bDataBits = 8;
    data.bParityType = 0;
    size = setup->wLength > 7 ? 7 : setup->wLength;

    rt_usbd_ep0_write(device, (void*)&data, size);

    return RT_EOK;
}

static rt_err_t _cdc_set_line_coding_callback(udevice_t device, rt_size_t size)
{
    RT_DEBUG_LOG(RT_DEBUG_USB, ("_cdc_set_line_coding_callback\n"));

    dcd_ep0_send_status(device->dcd);
    
    return RT_EOK;
}

/**
 * This function will handle cdc_set_line_coding request.
 *
 * @param device the usb device object.
 * @param setup the setup request.
 *
 * @return RT_EOK on successful.
 */
static rt_err_t _cdc_set_line_coding(udevice_t device, ureq_t setup)
{
    RT_ASSERT(device != RT_NULL);
    RT_ASSERT(setup != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("_cdc_set_line_coding\n"));

    rt_usbd_ep0_read(device, (void*)&line_coding, sizeof(struct ucdc_line_coding),
        _cdc_set_line_coding_callback);

    return RT_EOK;
}

/**
 * This function will handle cdc interface request.
 *
 * @param device the usb device object.
 * @param setup the setup request.
 *
 * @return RT_EOK on successful.
 */
static rt_err_t _interface_handler(ufunction_t func, ureq_t setup)
{
    struct vcom *data;

    RT_ASSERT(func != RT_NULL);
    RT_ASSERT(func->device != RT_NULL);
    RT_ASSERT(setup != RT_NULL);

    data = (struct vcom*)func->user_data;
    
    switch(setup->bRequest)
    {
    case CDC_SEND_ENCAPSULATED_COMMAND:
        break;
    case CDC_GET_ENCAPSULATED_RESPONSE:
        break;
    case CDC_SET_COMM_FEATURE:
        break;
    case CDC_GET_COMM_FEATURE:
        break;
    case CDC_CLEAR_COMM_FEATURE:
        break;
    case CDC_SET_LINE_CODING:
        _cdc_set_line_coding(func->device, setup);
        data->connected = RT_TRUE;        
        break;
    case CDC_GET_LINE_CODING:
        _cdc_get_line_coding(func->device, setup);
        break;
    case CDC_SET_CONTROL_LINE_STATE:
        dcd_ep0_send_status(func->device->dcd);
        break;
    case CDC_SEND_BREAK:
        break;
    default:
        rt_kprintf("unknown cdc request\n",setup->request_type);
        return -RT_ERROR;
    }

    return RT_EOK;
}

/**
 * This function will run cdc function, it will be called on handle set configuration request.
 *
 * @param func the usb function object.
 *
 * @return RT_EOK on successful.
 */
static rt_err_t _function_enable(ufunction_t func)
{
    struct vcom *data;

    RT_ASSERT(func != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("cdc function enable\n"));

    _vcom_reset_state(func);
    
    data = (struct vcom*)func->user_data;
    data->ep_out->buffer = rt_malloc(CDC_RX_BUFSIZE);

    data->ep_out->request.buffer = data->ep_out->buffer;
    data->ep_out->request.size = EP_MAXPACKET(data->ep_out);
    
    data->ep_out->request.req_type = UIO_REQUEST_READ_BEST;    
    rt_usbd_io_request(func->device, data->ep_out, &data->ep_out->request);
    
    return RT_EOK;
}

/**
 * This function will stop cdc function, it will be called on handle set configuration request.
 *
 * @param func the usb function object.
 *
 * @return RT_EOK on successful.
 */
static rt_err_t _function_disable(ufunction_t func)
{
    struct vcom *data;

    RT_ASSERT(func != RT_NULL);

    RT_DEBUG_LOG(RT_DEBUG_USB, ("cdc function disable\n"));

    _vcom_reset_state(func);

    data = (struct vcom*)func->user_data;
    if(data->ep_out->buffer != RT_NULL)
    {
        rt_free(data->ep_out->buffer);
        data->ep_out->buffer = RT_NULL;        
    }

    return RT_EOK;
}

static struct ufunction_ops ops =
{
    _function_enable,
    _function_disable,
    RT_NULL,
};

/**
 * This function will configure cdc descriptor.
 *
 * @param comm the communication interface number.
 * @param data the data interface number.
 *
 * @return RT_EOK on successful.
 */
static rt_err_t _cdc_descriptor_config(ucdc_comm_desc_t comm, 
    rt_uint8_t cintf_nr, ucdc_data_desc_t data, rt_uint8_t dintf_nr)
{
    comm->call_mgmt_desc.data_interface = dintf_nr;
    comm->union_desc.master_interface = cintf_nr;
    comm->union_desc.slave_interface0 = dintf_nr;
#ifdef RT_USB_DEVICE_COMPOSITE
    comm->iad_desc.bFirstInterface = cintf_nr;
#endif

    return RT_EOK;
}

/**
 * This function will create a cdc function instance.
 *
 * @param device the usb device object.
 *
 * @return RT_EOK on successful.
 */
ufunction_t rt_usbd_function_cdc_create(udevice_t device)
{
    ufunction_t func;
    struct vcom* data;
    uintf_t intf_comm, intf_data;
    ualtsetting_t comm_setting, data_setting;
    ucdc_data_desc_t data_desc;
    ucdc_comm_desc_t comm_desc;

    /* parameter check */
    RT_ASSERT(device != RT_NULL);

    /* set usb device string description */
    rt_usbd_device_set_string(device, _ustring);
    
    /* create a cdc function */
    func = rt_usbd_function_new(device, &dev_desc, &ops);
    rt_usbd_device_set_qualifier(device, &dev_qualifier);
    
    /* allocate memory for cdc vcom data */
    data = (struct vcom*)rt_malloc(sizeof(struct vcom));
    rt_memset(data, 0, sizeof(struct vcom));
    func->user_data = (void*)data;
    
    /* initilize vcom */
    rt_usb_vcom_init(func);

    /* create a cdc communication interface and a cdc data interface */
    intf_comm = rt_usbd_interface_new(device, _interface_handler);
    intf_data = rt_usbd_interface_new(device, _interface_handler);

    /* create a communication alternate setting and a data alternate setting */
    comm_setting = rt_usbd_altsetting_new(sizeof(struct ucdc_comm_descriptor));
    data_setting = rt_usbd_altsetting_new(sizeof(struct ucdc_data_descriptor));

    /* config desc in alternate setting */
    rt_usbd_altsetting_config_descriptor(comm_setting, &_comm_desc,
                                         (rt_off_t)&((ucdc_comm_desc_t)0)->intf_desc);
    rt_usbd_altsetting_config_descriptor(data_setting, &_data_desc, 0);
    /* configure the cdc interface descriptor */
    _cdc_descriptor_config(comm_setting->desc, intf_comm->intf_num, data_setting->desc, intf_data->intf_num);

    /* create a command endpoint */
    comm_desc = (ucdc_comm_desc_t)comm_setting->desc;
    data->ep_cmd = rt_usbd_endpoint_new(&comm_desc->ep_desc, _ep_cmd_handler);

    /* add the command endpoint to the cdc communication interface */
    rt_usbd_altsetting_add_endpoint(comm_setting, data->ep_cmd);

    /* add the communication alternate setting to the communication interface,
       then set default setting of the interface */
    rt_usbd_interface_add_altsetting(intf_comm, comm_setting);
    rt_usbd_set_altsetting(intf_comm, 0);

    /* add the communication interface to the cdc function */
    rt_usbd_function_add_interface(func, intf_comm);

    /* create a bulk in and a bulk endpoint */
    data_desc = (ucdc_data_desc_t)data_setting->desc;
    data->ep_out = rt_usbd_endpoint_new(&data_desc->ep_out_desc, _ep_out_handler);
    data->ep_in = rt_usbd_endpoint_new(&data_desc->ep_in_desc, _ep_in_handler);

    /* add the bulk out and bulk in endpoints to the data alternate setting */
    rt_usbd_altsetting_add_endpoint(data_setting, data->ep_in);
    rt_usbd_altsetting_add_endpoint(data_setting, data->ep_out);

    /* add the data alternate setting to the data interface
            then set default setting of the interface */
    rt_usbd_interface_add_altsetting(intf_data, data_setting);
    rt_usbd_set_altsetting(intf_data, 0);

    /* add the cdc data interface to cdc function */
    rt_usbd_function_add_interface(func, intf_data);
    
    return func;
}

/**
* UART device in RT-Thread
*/
static rt_err_t _vcom_configure(struct rt_serial_device *serial,
                                struct serial_configure *cfg)
{
    return RT_EOK;
}

static rt_err_t _vcom_control(struct rt_serial_device *serial,
                              int cmd, void *arg)
{
    switch (cmd)
    {
    case RT_DEVICE_CTRL_CLR_INT:
        /* disable rx irq */
        break;
    case RT_DEVICE_CTRL_SET_INT:
        /* enable rx irq */
        break;
    }

    return RT_EOK;
}

static int _vcom_getc(struct rt_serial_device *serial)
{
    int result;
    rt_uint8_t ch;
    rt_uint32_t level;
    struct ufunction *func;
    struct vcom *data;
    
    func = (struct ufunction*)serial->parent.user_data;
    data = (struct vcom*)func->user_data;

    result = -1;

    level = rt_hw_interrupt_disable();

    if(rt_ringbuffer_getchar(&data->rx_ringbuffer, &ch) != 0)
    {
        result = ch;
    }

    rt_hw_interrupt_enable(level);

    return result;
}

#ifdef VCOM_TX_USE_DMA
static rt_size_t _vcom_tx(struct rt_serial_device *serial, const char *buf, rt_size_t size,int direction)
{
    static struct vcom_tx_msg msg;

    RT_ASSERT(serial != RT_NULL);
    RT_ASSERT(buf != RT_NULL);

    rt_kprintf("%s\n",__func__);

    msg.buf     = buf;
    msg.serial  = serial;
    msg.size    = size;

    if (rt_mq_send(&vcom_tx_thread_mq, (void*)&msg, sizeof(struct vcom_tx_msg)) != RT_EOK)
    {
        rt_kprintf("vcom send msg fail\n");
        return 0;
    }

    return size;
}
#else
static int _vcom_putc(struct rt_serial_device *serial, char c)
{
    static struct vcom_tx_msg msg;

    RT_ASSERT(serial != RT_NULL);

    msg.buf     = (void *)((rt_uint32_t)c);
    msg.serial  = serial;
    msg.size    = 1;
    if (rt_mq_send(&vcom_tx_thread_mq, (void*)&msg, sizeof(struct vcom_tx_msg)) != RT_EOK)
    {
//        rt_kprintf("vcom send msg fail\n");
        return -1;
    }

    return 1;
}
#endif

static const struct rt_uart_ops usb_vcom_ops =
{
    _vcom_configure,
    _vcom_control,
#ifndef VCOM_TX_USE_DMA
    _vcom_putc,
    _vcom_getc,
    RT_NULL
#else
    RT_NULL,
    _vcom_getc,
    _vcom_tx
#endif

};

/* Vcom Tx Thread */
static void vcom_tx_thread_entry(void* parameter)
{
    struct vcom_tx_msg msg;
    rt_uint8_t  ch;
    while (1)
    {
        if (rt_mq_recv(&vcom_tx_thread_mq, (void*)&msg, sizeof(struct vcom_tx_msg), RT_WAITING_FOREVER) == RT_EOK)
        {
            struct ufunction *func;
            struct vcom *data;

            func = (struct ufunction*)msg.serial->parent.user_data;
            data = (struct vcom*)func->user_data;

            if (!data->connected)
            {
                /* drop msg */
#ifndef VCOM_TX_USE_DMA
                rt_hw_serial_isr(&data->serial,RT_SERIAL_EVENT_TX_DONE);
#else
                rt_hw_serial_isr(&data->serial,RT_SERIAL_EVENT_TX_DMADONE);
#endif
                continue;
            }
                    
            rt_completion_init(&data->wait);
#ifndef VCOM_TX_USE_DMA
            ch = (rt_uint8_t)((rt_uint32_t)msg.buf);
            data->ep_in->request.buffer     = (rt_uint8_t*)&ch;
#else
            data->ep_in->request.buffer     = (rt_uint8_t*)msg.buf;
#endif
            data->ep_in->request.size       = msg.size;
            data->ep_in->request.req_type   = UIO_REQUEST_WRITE;

            rt_usbd_io_request(func->device, data->ep_in, &data->ep_in->request);
            
            if (rt_completion_wait(&data->wait, TX_TIMEOUT) != RT_EOK)
            {
                rt_kprintf("vcom tx timeout\n");
            }
#ifndef VCOM_TX_USE_DMA
            rt_hw_serial_isr(&data->serial,RT_SERIAL_EVENT_TX_DONE);
#else
            rt_hw_serial_isr(&data->serial,RT_SERIAL_EVENT_TX_DMADONE);
#endif
        }
    }
}

static void rt_usb_vcom_init(struct ufunction *func)
{
    rt_err_t result = RT_EOK;
    struct serial_configure config;
    struct vcom *data = (struct vcom*)func->user_data;
    
    /* initialize ring buffer */
    rt_ringbuffer_init(&data->rx_ringbuffer, data->rx_rbp, CDC_RX_BUFSIZE);

    config.baud_rate    = BAUD_RATE_115200;
    config.data_bits    = DATA_BITS_8;
    config.stop_bits    = STOP_BITS_1;
    config.parity       = PARITY_NONE;
    config.bit_order    = BIT_ORDER_LSB;
    config.invert       = NRZ_NORMAL;
    config.bufsz        = CDC_RX_BUFSIZE;

    data->serial.ops        = &usb_vcom_ops;
    data->serial.serial_rx  = RT_NULL;
    data->serial.config     = config;

    /* register vcom device */
    rt_hw_serial_register(&data->serial, VCOM_DEVICE,
#ifndef VCOM_TX_USE_DMA
                          RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_INT_RX | RT_DEVICE_FLAG_INT_TX,
#else
                          RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_INT_RX | RT_DEVICE_FLAG_DMA_TX,
#endif
                          func);

    /* create an vcom message queue */
    rt_mq_init(&vcom_tx_thread_mq,
               "vcomq",
               vcom_tx_thread_mq_pool,
               VCOM_MQ_MSG_SZ,
               sizeof(vcom_tx_thread_mq_pool),
               RT_IPC_FLAG_FIFO);


    /* init usb device thread */
    rt_thread_init(&vcom_thread, "vcom",
                   vcom_tx_thread_entry, RT_NULL,
                   vcom_thread_stack, VCOM_TASK_STK_SIZE,
                   8, 20);
    result = rt_thread_startup(&vcom_thread);
    RT_ASSERT(result == RT_EOK);       
}

#endif