diff --git a/components/drivers/usb/usbdevice/core/core.c b/components/drivers/usb/usbdevice/core/core.c
new file mode 100644
index 0000000000..17875f18cb
--- /dev/null
+++ b/components/drivers/usb/usbdevice/core/core.c
@@ -0,0 +1,1250 @@
+/*
+ * File      : core.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 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
+ * 2012-10-01     Yi Qiu      first version
+ */
+
+#include <rtthread.h>
+#include <rtdevice.h>
+
+static rt_list_t device_list;
+
+/**
+ * This function will handle get_device_descriptor request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _get_device_descriptor(struct udevice* device, ureq_t setup)
+{
+    rt_size_t size;
+    
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_get_device_descriptor\n"));
+
+    /* device descriptor length should less than USB_DESC_LENGTH_DEVICE*/
+    size = (setup->length > USB_DESC_LENGTH_DEVICE) ? 
+        USB_DESC_LENGTH_DEVICE : setup->length;
+
+    /* send device descriptor to endpoint 0 */
+    dcd_ep_write(device->dcd, 0, (rt_uint8_t*)&device->dev_desc, 
+        size);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle get_config_descriptor request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _get_config_descriptor(struct udevice* device, ureq_t setup)
+{
+    rt_size_t size;
+    ucfg_desc_t cfg_desc;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_get_config_descriptor\n"));
+
+    cfg_desc = &device->curr_cfg->cfg_desc;
+    size = (setup->length > cfg_desc->wTotalLength) ? 
+        cfg_desc->wTotalLength : setup->length;
+
+    /* send configuration descriptor to endpoint 0 */
+    dcd_ep_write(device->dcd, 0, (rt_uint8_t*)cfg_desc, size);
+    
+    return RT_EOK;
+}
+
+/**
+ * This function will handle get_string_descriptor request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful, -RT_ERROR on invalid request.
+ */
+static rt_err_t _get_string_descriptor(struct udevice* device, ureq_t setup)
+{
+    struct ustring_descriptor str_desc;
+    rt_uint8_t index, i;
+    rt_uint32_t len;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_get_string_descriptor\n"));
+
+    str_desc.type = USB_DESC_TYPE_STRING;
+    index = setup->value & 0xFF;
+
+    if(index > USB_STRING_INTERFACE_INDEX) 
+    {
+        rt_kprintf("unknown string index\n");
+        dcd_ep0_stall(device->dcd);
+        return -RT_ERROR;
+    }    
+    if(index == 0)
+    {
+        str_desc.bLength = 4;
+        str_desc.String[0] = 0x09;
+        str_desc.String[1] = 0x04;        
+    }
+    else
+    {
+        len = rt_strlen(device->str[index]);
+        str_desc.bLength = len*2 + 2;
+
+        for(i=0; i<len; i++)  
+        {
+            str_desc.String[i*2] = device->str[index][i];
+            str_desc.String[i*2 + 1] = 0;
+        }
+    }
+
+    /* send string descriptor to endpoint 0 */
+    dcd_ep_write(device->dcd, 0, (rt_uint8_t*)&str_desc, 
+        str_desc.bLength);         
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle get_descriptor request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _get_descriptor(struct udevice* device, ureq_t setup)
+{
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+    
+    if(setup->request_type == USB_REQ_TYPE_DIR_IN)
+    {
+        switch(setup->value >> 8)
+        {
+        case USB_DESC_TYPE_DEVICE:
+            _get_device_descriptor(device, setup);
+            break;
+        case USB_DESC_TYPE_CONFIGURATION:        
+            _get_config_descriptor(device, setup);
+            break;
+        case USB_DESC_TYPE_STRING:
+            _get_string_descriptor(device, setup);
+            break;
+        default:
+            rt_kprintf("unknown descriptor\n");
+            dcd_ep0_stall(device->dcd);
+            break;
+        }
+    }
+    else
+    {
+        rt_kprintf("request direction error\n");
+        dcd_ep0_stall(device->dcd);
+    }
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle get_interface request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _get_interface(struct udevice* device, ureq_t setup)
+{
+    rt_uint8_t value;
+    uintf_t intf;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_get_interface\n"));
+
+    /* find the specified interface and its alternate setting */
+    intf = rt_usbd_find_interface(device, setup->index & 0xFF);
+    value = intf->curr_setting->intf_desc->bAlternateSetting;
+
+    /* send the interface alternate setting to endpoint 0*/
+    dcd_ep_write(device->dcd, 0, &value, 1);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle set_interface request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _set_interface(struct udevice* device, ureq_t setup)
+{
+    uintf_t intf;
+    uep_t ep;
+    struct rt_list_node* i;
+    ualtsetting_t setting;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_set_interface\n"));
+
+    setup->index & 0xFF;
+    setup->value & 0xFF;
+
+    /* find the specified interface */
+    intf = rt_usbd_find_interface(device, setup->index & 0xFF);
+
+    /* set alternate setting to the interface */
+    rt_usbd_set_altsetting(intf, setup->value & 0xFF);
+    setting = intf->curr_setting;
+
+    /* start all endpoints of the interface alternate setting */
+    for(i=setting->ep_list.next; i != &setting->ep_list; i=i->next)
+    {
+        ep = (uep_t)rt_list_entry(i, struct uendpoint, list);
+        dcd_ep_stop(device->dcd, ep);
+        dcd_ep_run(device->dcd, ep);
+    }
+    
+    return RT_EOK;
+}
+
+/**
+ * This function will handle get_config request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _get_config(struct udevice* device, ureq_t setup)
+{
+    rt_uint8_t value;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+    RT_ASSERT(device->curr_cfg != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_get_config\n"));
+
+    /* get current configuration */
+    value = device->curr_cfg->cfg_desc.bConfigurationValue;
+
+    /* write the current configuration to endpoint 0 */
+    dcd_ep_write(device->dcd, 0, &value, 1);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle set_config request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _set_config(struct udevice* device, ureq_t setup)
+{
+    struct rt_list_node *i, *j, *k;
+    uconfig_t cfg;
+    uintf_t intf;
+    ualtsetting_t setting;
+    uep_t ep;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_set_config\n"));
+
+    /* set current configuration */
+    rt_usbd_set_config(device, setup->value);
+    cfg = device->curr_cfg;
+
+    for (i=cfg->cls_list.next; i!=&cfg->cls_list; i=i->next)
+    {
+        /* run all classes and their endpoints in the configuration */
+        uclass_t cls = (uclass_t)rt_list_entry(i, struct uclass, list);
+        for(j=cls->intf_list.next; j!=&cls->intf_list; j=j->next)
+        {
+            intf = (uintf_t)rt_list_entry(j, struct uinterface, list);
+            setting = intf->curr_setting;
+            for(k=setting->ep_list.next; k != &setting->ep_list; k=k->next)
+            {
+                ep = (uep_t)rt_list_entry(k, struct uendpoint, list);
+
+                /* first stop then start endpoint */
+                dcd_ep_stop(device->dcd, ep);
+                dcd_ep_run(device->dcd, ep);
+            }
+        }
+        /* after running all endpoints, then run class */
+        if(cls->ops->run != RT_NULL) cls->ops->run(device);
+    }
+        
+    /* issue status stage */
+    rt_device_control((rt_device_t)device->dcd, CONTROL_SEND_STATUS, RT_NULL);
+    
+    return RT_EOK;
+}
+
+/**
+ * This function will handle set_address request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _set_address(struct udevice* device, ureq_t setup)
+{
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+    
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("_set_address\n"));
+
+    /* set address in device control driver */
+    dcd_set_address(device->dcd, setup->value);
+
+    /* issue status stage */
+    rt_device_control((rt_device_t)device->dcd, CONTROL_SEND_STATUS, RT_NULL);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle standard request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful.
+ */
+static rt_err_t _standard_request(struct udevice* device, ureq_t setup)
+{   
+    udcd_t dcd;
+    rt_uint16_t value = 0;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    dcd = device->dcd;
+
+    switch(setup->request_type & USB_REQ_TYPE_RECIPIENT_MASK)
+    {
+    case USB_REQ_TYPE_DEVICE:
+        switch(setup->request)
+        {
+        case USB_REQ_GET_STATUS:
+            dcd_ep_write(device->dcd, 0, &value, 2);
+            break;
+        case USB_REQ_CLEAR_FEATURE:
+            dcd_clear_feature(dcd, setup->value);
+            break;
+        case USB_REQ_SET_FEATURE:
+            dcd_set_feature(dcd, setup->value);
+            break;
+        case USB_REQ_SET_ADDRESS:
+            _set_address(device, setup);
+            break;
+        case USB_REQ_GET_DESCRIPTOR:
+            _get_descriptor(device, setup);
+            break;
+        case USB_REQ_SET_DESCRIPTOR:
+            dcd_ep0_stall(dcd);
+            break;
+        case USB_REQ_GET_CONFIGURATION:
+            _get_config(device, setup);
+            break;
+        case USB_REQ_SET_CONFIGURATION:
+            _set_config(device, setup);
+            break;
+        default:
+            rt_kprintf("unknown device request\n");
+            dcd_ep0_stall(device->dcd);
+            break;
+        }
+        break;
+    case USB_REQ_TYPE_INTERFACE:
+        switch(setup->request)
+        {
+        case USB_REQ_GET_INTERFACE:
+            _get_interface(device, setup);
+            break;
+        case USB_REQ_SET_INTERFACE:
+            _set_interface(device, setup);
+            break;
+        default:
+            rt_kprintf("unknown interface request\n");
+            dcd_ep0_stall(device->dcd);
+            break;
+        }
+        break;
+    case USB_REQ_TYPE_ENDPOINT:
+        switch(setup->request)
+        {
+        case USB_REQ_GET_STATUS:            
+            /* TODO */
+            dcd_ep_write(dcd, 0, &value, 2);
+            break;
+        case USB_REQ_CLEAR_FEATURE:
+            dcd_clear_feature(dcd, setup->value);
+            break;
+        case USB_REQ_SET_FEATURE:
+            dcd_set_feature(dcd, setup->value);
+            break;
+        case USB_REQ_SYNCH_FRAME:
+            break;
+        default:
+            rt_kprintf("unknown endpoint request\n");
+            dcd_ep0_stall(device->dcd);
+            break;
+        }
+        break;
+    case USB_REQ_TYPE_OTHER:
+        rt_kprintf("unknown other type request\n");
+        dcd_ep0_stall(device->dcd);
+        break;
+    default:
+        rt_kprintf("unknown type request\n");
+        dcd_ep0_stall(device->dcd);
+        break;
+    }
+
+    return RT_EOK;
+}
+
+/**
+ * This function will handle class request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful, -RT_ERROR on invalid request.
+ */
+static rt_err_t _class_request(udevice_t device, ureq_t setup)
+{
+    uintf_t intf;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    /* verify request value */
+    if(setup->index > device->curr_cfg->cfg_desc.bNumInterfaces)
+    {
+        dcd_ep0_stall(device->dcd);
+        return -RT_ERROR;
+    }
+
+    switch(setup->request_type & USB_REQ_TYPE_RECIPIENT_MASK)
+    {
+    case USB_REQ_TYPE_INTERFACE:
+        intf = rt_usbd_find_interface(device, setup->index & 0xFF);
+        intf->handler(device, setup);        
+        break;
+    case USB_REQ_TYPE_ENDPOINT:
+        break;
+    default:
+        rt_kprintf("unknown class request type\n");
+        dcd_ep0_stall(device->dcd);
+        break;
+    }   
+    
+    return RT_EOK;
+}
+
+/**
+ * This function will handle setup request.
+ *
+ * @param device the usb device object.
+ * @param setup the setup request.
+ *
+ * @return RT_EOK on successful, -RT_ERROR on invalid request.
+ */
+static rt_err_t _setup_request(udevice_t device, ureq_t setup)
+{
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(setup != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("[\n"));
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("setup_request_handler 0x%x\n", setup->request_type));
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("value 0x%x\n", setup->value));
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("length 0x%x\n", setup->length));
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("index 0x%x\n", setup->index));
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("request 0x%x\n", setup->request));
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("]\n"));
+    
+    switch((setup->request_type & USB_REQ_TYPE_MASK))
+    {
+    case USB_REQ_TYPE_STANDARD:
+        _standard_request(device, setup);
+        break;
+    case USB_REQ_TYPE_CLASS:
+        _class_request(device, setup);
+        break;
+    case USB_REQ_TYPE_VENDOR:
+        rt_kprintf("vendor type request\n");
+        break;
+    default:
+        rt_kprintf("unknown setup request type\n");
+        dcd_ep0_stall(device->dcd);
+        return -RT_ERROR;
+    }
+
+    return RT_EOK;
+}
+
+/**
+ * This function will create an usb device object.
+ *
+ * @param ustring the usb string array to contain string descriptor.
+ *
+ * @return an usb device object on success, RT_NULL on fail.
+ */
+udevice_t rt_usbd_device_create(const char** ustring)
+{
+    udevice_t udevice;
+
+    /* parameter check */
+    RT_ASSERT(ustring != RT_NULL);
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_device_create\n"));
+
+    /* allocate memory for the object */
+    udevice = rt_malloc(sizeof(struct udevice));
+    if(udevice == RT_NULL)
+    {
+        rt_kprintf("alloc memery failed\n");
+        return RT_NULL;
+    }
+    rt_memset(udevice, 0, sizeof(struct udevice));
+    
+    /* set string descriptor array to the device object */
+    udevice->str = ustring;
+
+    /* to initialize configuration list */
+    rt_list_init(&udevice->cfg_list);
+
+    /* insert the device object to device list */
+    rt_list_insert_after(&device_list, &udevice->list);    
+
+    return udevice;
+}
+
+/**
+ * This function will set an usb controller driver to a device.
+ *
+ * @param device the usb device object.
+ * @param dcd the usb device controller driver.
+ *
+ * @return RT_EOK on successful.
+ */
+rt_err_t rt_usbd_device_set_controller(udevice_t device, udcd_t dcd)
+{
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(dcd != RT_NULL);
+
+    /* set usb device controller driver to the device */
+    device->dcd = dcd;
+
+    return RT_EOK;
+}
+
+/**
+ * This function will set an usb device descriptor to a device.
+ *
+ * @param device the usb device object.
+ * @param dev_desc the usb device descriptor.
+ *
+ * @return RT_EOK on successful.
+ */
+rt_err_t rt_usbd_device_set_descriptor(udevice_t device, udev_desc_t dev_desc)
+{
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(dev_desc != RT_NULL);
+    
+    /* copy the usb device descriptor to the device */
+    rt_memcpy((void *)&device->dev_desc, (void *)dev_desc, USB_DESC_LENGTH_DEVICE);
+    
+    return RT_EOK;
+}
+
+/**
+ * This function will create an usb configuration object.
+ *
+ * @param none.
+ *
+ * @return an usb configuration object.
+ */
+uconfig_t rt_usbd_config_create(void)
+{
+    uconfig_t cfg;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_config_create\n"));
+
+    /* allocate memory for the object */
+    cfg = rt_malloc(sizeof(struct uconfig));
+    if(cfg == RT_NULL)
+    {
+        rt_kprintf("alloc memery failed\n");
+        return RT_NULL;
+    }
+    rt_memset(cfg, 0, sizeof(struct uconfig));
+
+    /* set default value */
+    cfg->cfg_desc.bLength = USB_DESC_LENGTH_CONFIG;
+    cfg->cfg_desc.type = USB_DESC_TYPE_CONFIGURATION;    
+    cfg->cfg_desc.wTotalLength = USB_DESC_LENGTH_CONFIG;
+    cfg->cfg_desc.bmAttributes = 0xC0;
+    cfg->cfg_desc.MaxPower = 0x32;
+
+    /* to initialize class object list */
+    rt_list_init(&cfg->cls_list);
+
+    return cfg;
+}
+
+/**
+ * This function will create an usb interface object.
+ *
+ * @param device the usb device object.
+ * @handler the callback handler of object
+ *
+ * @return an usb interface object on success, RT_NULL on fail.
+ */
+uintf_t rt_usbd_interface_create(udevice_t device, 
+    rt_err_t (*handler)(struct udevice*, ureq_t setup))
+{
+    uintf_t intf;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_interface_create\n"));
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    
+    /* allocate memory for the object */
+    intf = (uintf_t)rt_malloc(sizeof(struct uinterface)); 
+    if(intf == RT_NULL)
+    {
+        rt_kprintf("alloc memery failed\n");
+        return RT_NULL;
+    }
+    intf->intf_num = device->nr_intf;
+    device->nr_intf++;
+    intf->handler = handler;
+    intf->curr_setting = RT_NULL;
+
+    /* to initialize the alternate setting object list */    
+    rt_list_init(&intf->setting_list);
+
+    return intf;
+}
+
+/**
+ * This function will create an usb alternate setting object.
+ *
+ * @param intf_desc the interface descriptor.
+ * @desc_size the size of the interface descriptor.
+ *
+ * @return an usb alternate setting object on success, RT_NULL on fail.
+ */
+ualtsetting_t rt_usbd_altsetting_create(uintf_desc_t intf_desc, rt_size_t desc_size)
+{
+    ualtsetting_t setting;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_altsetting_create\n"));
+
+    /* parameter check */
+    RT_ASSERT(intf_desc != RT_NULL);
+    RT_ASSERT(desc_size > 0);
+
+    /* allocate memory for the object */
+    setting = (ualtsetting_t)rt_malloc(sizeof(struct ualtsetting));
+    if(setting == RT_NULL)
+    {
+        rt_kprintf("alloc memery failed\n");
+        return RT_NULL;
+    }
+    setting->desc_size = desc_size;
+    setting->intf_desc = intf_desc;
+
+    /* to initialize endpoint list */
+    rt_list_init(&setting->ep_list);
+
+    return setting;
+}
+
+/**
+ * This function will create an usb class object.
+ *
+ * @param device the usb device object.
+ * @param dev_desc the device descriptor.
+ * @param ops the operation set.
+ *
+ * @return an usb class object on success, RT_NULL on fail.
+ */
+uclass_t rt_usbd_class_create(udevice_t device, udev_desc_t dev_desc, 
+    uclass_ops_t ops)
+{
+    uclass_t cls;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_class_create\n"));
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(dev_desc != RT_NULL);
+
+    /* allocate memory for the object */
+    cls = (uclass_t)rt_malloc(sizeof(struct uclass));
+    if(cls == RT_NULL)
+    {
+        rt_kprintf("alloc memery failed\n");
+        return RT_NULL;
+    }
+    cls->dev_desc = dev_desc;
+    cls->ops = ops;
+    cls->device = device;
+
+    /* to initialize interface list */
+    rt_list_init(&cls->intf_list);
+
+    return cls;
+}
+
+/**
+ * This function will create an usb endpoint object.
+ *
+ * @param ep_desc the endpoint descriptor.
+ * @handler the callback handler of object
+ *
+ * @return an usb endpoint object on success, RT_NULL on fail.
+ */
+uep_t rt_usbd_endpoint_create(uep_desc_t ep_desc, 
+    rt_err_t (*handler)(struct udevice*, rt_size_t size))
+{
+    uep_t ep;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_endpoint_create\n"));
+
+    /* parameter check */
+    RT_ASSERT(ep_desc != RT_NULL);
+
+    /* allocate memory for the object */
+    ep = (uep_t)rt_malloc(sizeof(struct uendpoint)); 
+    if(ep == RT_NULL)
+    {
+        rt_kprintf("alloc memery failed\n");
+        return RT_NULL;
+    }
+    ep->ep_desc = ep_desc;
+    ep->handler = handler;
+
+    /* allocate buffer for endpoint */
+    ep->buffer = (rt_uint8_t*)rt_malloc(ep_desc->wMaxPacketSize);
+
+    return ep;
+}
+
+/**
+ * This function will find an usb device object.
+ *
+ * @dcd usd device controller driver.
+ *
+ * @return an usb device object on found or RT_NULL on not found.
+ */
+udevice_t rt_usbd_find_device(udcd_t dcd)
+{
+    struct rt_list_node* node;
+    udevice_t device;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_find_device\n"));
+    
+    /* parameter check */
+    RT_ASSERT(dcd != RT_NULL);
+    
+    /* search a device in the the device list */
+    for (node = device_list.next; node != &device_list; node = node->next)
+    {
+        device = (udevice_t)rt_list_entry(node, struct udevice, list);
+        if(device->dcd == dcd) return device;
+    }
+
+    rt_kprintf("can't find device\n");
+    return RT_NULL;
+}
+
+/**
+ * This function will find an usb configuration object.
+ *
+ * @param device the usb device object.
+ * @param value the configuration number.
+ *
+ * @return an usb configuration object on found or RT_NULL on not found.
+ */
+uconfig_t rt_usbd_find_config(udevice_t device, rt_uint8_t value)
+{
+    struct rt_list_node* node;
+    uconfig_t cfg = RT_NULL;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_find_config\n"));
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(value <= device->dev_desc.bNumConfigurations);
+
+    /* search a configration in the the device */
+    for (node = device->cfg_list.next; node != &device->cfg_list; node = node->next)
+    {
+        cfg = (uconfig_t)rt_list_entry(node, struct udevice, list);
+        if(cfg->cfg_desc.bConfigurationValue == value) return cfg;
+    }
+
+    rt_kprintf("can't find configuration %d\n", value);
+    return RT_NULL;
+}
+
+/**
+ * This function will find an usb interface object.
+ *
+ * @param device the usb device object.
+ * @param value the interface number.
+ *
+ * @return an usb configuration object on found or RT_NULL on not found.
+ */
+uintf_t rt_usbd_find_interface(udevice_t device, rt_uint8_t value)
+{
+    uep_t ep;
+    struct rt_list_node *i, *j;
+    uclass_t cls;
+    uintf_t intf;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_find_interface\n"));
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(value < device->nr_intf);
+
+    /* search an interface in the current configuration */
+    for (i=device->curr_cfg->cls_list.next; 
+        i!=&device->curr_cfg->cls_list; i=i->next)
+    {
+        cls = (uclass_t)rt_list_entry(i, struct uclass, list);        
+        for(j=cls->intf_list.next; j!=&cls->intf_list; j=j->next)
+        {
+            intf = (uintf_t)rt_list_entry(j, struct uinterface, list);
+            if(intf->intf_num == value)
+                return intf;
+        }
+    }    
+
+    rt_kprintf("can't find interface %d\n", value);
+    return RT_NULL;
+}
+
+/**
+ * This function will find an usb interface alternate setting object.
+ *
+ * @param device the usb device object.
+ * @param value the alternate setting number.
+ *
+ * @return an usb interface alternate setting object on found or RT_NULL on not found.
+ */
+ualtsetting_t rt_usbd_find_altsetting(uintf_t intf, rt_uint8_t value)
+{
+    struct rt_list_node *i;
+    ualtsetting_t setting;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_find_altsetting\n"));
+
+    /* parameter check */
+    RT_ASSERT(intf != RT_NULL);
+
+    if(intf->curr_setting != RT_NULL)
+    {
+        /* if the value equal to the current alternate setting, then do not search */
+        if(intf->curr_setting->intf_desc->bAlternateSetting == value)
+            return intf->curr_setting;
+    }
+    
+    /* search a setting in the alternate setting list */
+    for(i=intf->setting_list.next; i!=&intf->setting_list; i=i->next)
+    {
+        setting =(ualtsetting_t)rt_list_entry(i, struct ualtsetting, list);
+        if(setting->intf_desc->bAlternateSetting == value)
+            return setting;
+    }
+
+    rt_kprintf("can't find alternate setting %d\n", value);
+    return RT_NULL;
+}
+
+/**
+ * This function will find an usb endpoint object.
+ *
+ * @param device the usb device object.
+ * @param ep_addr endpoint address.
+ *
+ * @return an usb endpoint object on found or RT_NULL on not found.
+ */
+uep_t rt_usbd_find_endpoint(udevice_t device, rt_uint8_t ep_addr)
+{
+    uep_t ep;
+    struct rt_list_node *i, *j, *k;
+    uclass_t cls;
+    uintf_t intf;
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    
+    /* search a endpoint in the current configuration */
+    for (i=device->curr_cfg->cls_list.next; 
+        i!=&device->curr_cfg->cls_list; i=i->next)
+    {
+        cls = (uclass_t)rt_list_entry(i, struct uclass, list);        
+        for(j=cls->intf_list.next; j!=&cls->intf_list; j=j->next)
+        {
+            intf = (uintf_t)rt_list_entry(j, struct uinterface, list);
+            for(k=intf->curr_setting->ep_list.next; 
+                k!=&intf->curr_setting->ep_list; k=k->next)
+            {
+                ep = (uep_t)rt_list_entry(k, struct uendpoint, list);
+                if(ep->ep_desc->bEndpointAddress == ep_addr)
+                    return ep;
+            }
+        }
+    }
+
+    rt_kprintf("can't find endpoint 0x%x\n", ep_addr);
+    return RT_NULL;
+}
+
+/**
+ * This function will add a configuration to an usb device.
+ *
+ * @param device the usb device object.
+ * @param cfg the configuration object.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_device_add_config(udevice_t device, uconfig_t cfg)
+{
+    struct rt_list_node *i, *j, *k;
+    uclass_t cls;
+    uintf_t intf;
+    uep_t ep;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_device_add_config\n"));
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(cfg != RT_NULL); 
+
+    /* set configuration number to the configuration descriptor */
+    cfg->cfg_desc.bConfigurationValue = device->dev_desc.bNumConfigurations + 1;
+    device->dev_desc.bNumConfigurations++;
+
+    for (i=cfg->cls_list.next; i!=&cfg->cls_list; i=i->next)
+    {
+        cls = (uclass_t)rt_list_entry(i, struct uclass, list);
+        for(j=cls->intf_list.next; j!=&cls->intf_list; j=j->next)
+        {
+            intf = (uintf_t)rt_list_entry(j, struct uinterface, list);
+            cfg->cfg_desc.bNumInterfaces++;
+            
+            /* allocate address for every endpoint in the interface alternate setting */
+            for(k=intf->curr_setting->ep_list.next; 
+                k!=&intf->curr_setting->ep_list; k=k->next)
+            {
+                ep = (uep_t)rt_list_entry(k, struct uendpoint, list);
+                dcd_ep_alloc(device->dcd, ep);             
+            }
+            
+            /* construct complete configuration descriptor */
+            rt_memcpy((void*)&cfg->cfg_desc.data[cfg->cfg_desc.wTotalLength - 
+                USB_DESC_LENGTH_CONFIG], (void*)intf->curr_setting->intf_desc,
+                intf->curr_setting->desc_size);
+            cfg->cfg_desc.wTotalLength += intf->curr_setting->desc_size;
+        }
+    }    
+
+    /* insert the configuration to the list */
+    rt_list_insert_after(&device->cfg_list, &cfg->list);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will add a class to a configuration.
+ *
+ * @param cfg the configuration object.
+ * @param cls the class object.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_config_add_class(uconfig_t cfg, uclass_t cls)
+{
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_config_add_class\n"));
+
+    /* parameter check */
+    RT_ASSERT(cfg != RT_NULL);
+    RT_ASSERT(cls != RT_NULL);
+
+    /* insert the class to the list */
+    rt_list_insert_after(&cfg->cls_list, &cls->list);
+    
+    return RT_EOK;
+}
+
+/**
+ * This function will add an interface to a class.
+ *
+ * @param cls the class object.
+ * @param intf the interface object.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_class_add_interface(uclass_t cls, uintf_t intf)
+{
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_class_add_interface\n"));
+
+    /* parameter check */
+    RT_ASSERT(cls != RT_NULL);
+    RT_ASSERT(intf != RT_NULL);
+
+    /* insert the interface to the list */
+    rt_list_insert_after(&cls->intf_list, &intf->list);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will add an alternate setting to an interface.
+ *
+ * @param intf the interface object.
+ * @param setting the alternate setting object.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_interface_add_altsetting(uintf_t intf, ualtsetting_t setting)
+{
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_interface_add_altsetting\n"));
+
+    /* parameter check */
+    RT_ASSERT(intf != RT_NULL);
+    RT_ASSERT(setting != RT_NULL);
+
+    setting->intf_desc->bInterfaceNumber = intf->intf_num;
+
+    /* insert the alternate setting to the list */
+    rt_list_insert_after(&intf->setting_list, &setting->list);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will add an endpoint to an alternate setting.
+ *
+ * @param setting the alternate setting object.
+ * @param ep the endpoint object.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_altsetting_add_endpoint(ualtsetting_t setting, uep_t ep)
+{
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_altsetting_add_endpoint\n"));
+
+    /* parameter check */
+    RT_ASSERT(setting != RT_NULL);
+    RT_ASSERT(ep != RT_NULL);
+
+    /* insert the endpoint to the list */
+    rt_list_insert_after(&setting->ep_list, &ep->list);
+
+    return RT_EOK;
+}
+
+/**
+ * This function will set an alternate setting for an interface.
+ *
+ * @param intf_desc the interface descriptor.
+ * @param value the alternate setting number.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_set_altsetting(uintf_t intf, rt_uint8_t value)
+{
+    ualtsetting_t setting;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_set_altsetting\n"));
+
+    /* parameter check */
+    RT_ASSERT(intf != RT_NULL);
+    RT_ASSERT(setting != RT_NULL);
+
+    /* find an alternate setting */
+    setting = rt_usbd_find_altsetting(intf, value);
+
+    /* set as current alternate setting */
+    intf->curr_setting = setting;
+
+    return RT_EOK;
+}
+
+/**
+ * This function will set a configuration for an usb device.
+ *
+ * @param device the usb device object.
+ * @param value the configuration number.
+ *
+ * @return RT_EOK.
+ */
+rt_err_t rt_usbd_set_config(udevice_t device, rt_uint8_t value)
+{
+    uconfig_t cfg;
+
+    RT_DEBUG_LOG(RT_DEBUG_USB, ("rt_usbd_set_config\n"));
+
+    /* parameter check */
+    RT_ASSERT(device != RT_NULL);
+    RT_ASSERT(value <= device->dev_desc.bNumConfigurations);
+
+    /* find a configuration */
+    cfg = rt_usbd_find_config(device, value);
+
+    /* set as current configuration */
+    device->curr_cfg = cfg;
+
+    return RT_TRUE;
+}
+
+static struct rt_messagequeue *usb_mq;
+
+/**
+ * This function is the main entry of usb device thread, it is in charge of
+ * processing all messages received from the usb message buffer.
+ *
+ * @param parameter the parameter of the usb device thread.
+ *
+ * @return none.
+ */
+static void rt_usbd_thread_entry(void* parameter)
+{    
+    while(1)
+    {    
+        struct udev_msg msg;        
+        udevice_t device;
+        uep_t ep;
+        
+        /* receive message */
+        if(rt_mq_recv(usb_mq, &msg, sizeof(struct udev_msg), RT_WAITING_FOREVER) 
+            != RT_EOK ) continue;
+
+        //RT_DEBUG_LOG(RT_DEBUG_USB, ("msg type %d\n", msg.type));
+        
+        switch (msg.type)
+        {        
+        case USB_MSG_SETUP_NOTIFY:
+            device = rt_usbd_find_device(msg.content.setup_msg.dcd);      
+            if(device != RT_NULL)
+                _setup_request(device, (ureq_t)msg.content.setup_msg.packet);                       
+            else
+                rt_kprintf("invalid usb device\n");
+            break;
+        case USB_MSG_DATA_NOTIFY:
+            ep = rt_usbd_find_endpoint(device, msg.content.ep_msg.ep_addr);
+            if(ep != RT_NULL) 
+                ep->handler(device, msg.content.ep_msg.size);
+            else 
+                rt_kprintf("invalid endpoint\n");
+            break;
+        default:
+            break;
+        }            
+    }
+}
+
+/**
+ * This function will post an message to usb message queue,
+ *
+ * @param msg the message to be posted
+ * @param size the size of the message .
+ *
+ * @return the error code, RT_EOK on successfully.
+ */
+rt_err_t rt_usbd_post_event(struct udev_msg* msg, rt_size_t size)
+{
+    RT_ASSERT(msg != RT_NULL);
+
+    /* send message to usb message queue */
+    return rt_mq_send(usb_mq, (void*)msg, size);
+}
+
+/**
+ * This function will initialize usb device thread.
+ *
+ * @return none.
+ *
+ */
+rt_err_t rt_usbd_core_init(void)
+{
+    rt_thread_t thread;
+    
+    rt_list_init(&device_list);
+    
+    /* create an usb message queue */
+    usb_mq = rt_mq_create("usbd", 32, 16, RT_IPC_FLAG_FIFO);
+    
+    /* create usb device thread */
+    thread = rt_thread_create("usbd", rt_usbd_thread_entry, RT_NULL, 
+        2048, 8, 20);
+    if(thread != RT_NULL)
+    {
+        /* startup usb device thread */
+        rt_thread_startup(thread);
+    }
+    
+    return RT_EOK;
+}
+