/*!
    \file  usbd_std.c
    \brief USB device stand routines
    \note  about USB standard, please refer to the USB2.0 protocol

    \version 2017-02-10, V1.0.0, firmware for GD32F30x
    \version 2018-10-10, V1.1.0, firmware for GD32F30x
    \version 2018-12-25, V2.0.0, firmware for GD32F30x
*/

/*
    Copyright (c) 2018, GigaDevice Semiconductor Inc.

    All rights reserved.

    Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice, this 
       list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice, 
       this list of conditions and the following disclaimer in the documentation 
       and/or other materials provided with the distribution.
    3. Neither the name of the copyright holder nor the names of its contributors 
       may be used to endorse or promote products derived from this software without 
       specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
OF SUCH DAMAGE.
*/

#include "usbd_std.h"

uint8_t g_device_address = 0U;

/* USB enumeration handle functions */
static void usbd_getdescriptor     (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_setaddress        (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_setconfiguration  (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_getconfiguration  (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_getstatus         (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_setfeature        (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_clearfeature      (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_reserved          (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_setdescriptor     (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_getinterface      (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_setinterface      (usbd_core_handle_struct *pudev, usb_device_req_struct *req);
static void usbd_synchframe        (usbd_core_handle_struct *pudev, usb_device_req_struct *req);

static uint8_t* usbd_device_descriptor_get        (usbd_core_handle_struct *pudev, 
                                                   uint8_t index, 
                                                   uint16_t *pLen);

static uint8_t* usbd_configuration_descriptor_get (usbd_core_handle_struct *pudev, 
                                                   uint8_t index, 
                                                   uint16_t *pLen);

static uint8_t* usbd_string_descriptor_get        (usbd_core_handle_struct *pudev, 
                                                   uint8_t index, 
                                                   uint16_t *pLen);

#ifdef LPM_ENABLED
static uint8_t* usbd_bos_descriptor_get           (usbd_core_handle_struct *pudev, uint16_t *pLen);
#endif /* LPM_ENABLED */

/* standard device request handler */
static void (*standard_device_request[])(usbd_core_handle_struct *pudev, usb_device_req_struct *req) =
{
    usbd_getstatus,
    usbd_clearfeature,
    usbd_reserved,
    usbd_setfeature,
    usbd_reserved,
    usbd_setaddress,
    usbd_getdescriptor,
    usbd_setdescriptor,
    usbd_getconfiguration,
    usbd_setconfiguration,
    usbd_getinterface,
    usbd_setinterface,
    usbd_synchframe,
};

/* get standard descriptor handler */
static uint8_t* (*standard_descriptor_get[])(usbd_core_handle_struct *pudev, uint8_t index, uint16_t *pLen) = 
{
    usbd_device_descriptor_get,
    usbd_configuration_descriptor_get,
    usbd_string_descriptor_get
};

/*!
    \brief      USB setup stage processing
    \param[in]  pudev: pointer to USB device instance
    \param[out] none
    \retval     USB device operation status
*/
uint8_t  usbd_setup_transaction (usbd_core_handle_struct *pudev)
{
    usb_device_req_struct req;

    usbd_setup_request_parse (pudev, &req);

    switch (req.bmRequestType & USB_REQ_MASK) {
    /* standard device request */
    case USB_STANDARD_REQ:
        usbd_standard_request(pudev, &req);
        break;
    /* device class request */
    case USB_CLASS_REQ:
        usbd_device_class_request(pudev, &req);
        break;
    /* vendor defined request */
    case USB_VENDOR_REQ:
        usbd_vendor_request(pudev, &req);
        break;
    default:
        usbd_ep_stall(pudev, 0x00U);
        break;
    }
    return USBD_OK;
}

/*!
    \brief      data out stage processing
    \param[in]  pudev: pointer to USB device instance
    \param[in]  ep_num: endpoint identifier(0..7)
    \param[out] none
    \retval     USB device operation status
*/
uint8_t  usbd_out_transaction (usbd_core_handle_struct *pudev, uint8_t ep_num)
{
    usb_ep_struct *ep = &pudev->out_ep[ep_num];

    if (0U == ep_num) {
        if (0U != pudev->ctl_count) {
            if (ep->trs_len > ep->maxpacket) {
                /* one data packet has been received, update trs_len */
                ep->trs_len -= ep->maxpacket;

                /* continue to receive remain data */
                usbd_ep_rx(pudev, EP0_OUT, ep->trs_buf, (uint16_t)ep->trs_len);
            } else {
                if (USBD_CONFIGURED == pudev->status) {
                    /* device class handle */
                    pudev->class_data_handler(pudev, USBD_RX, EP0);
                }

                /* enter the control transaction status stage */
                USBD_CONTRL_STATUS_TX();

                pudev->ctl_count = 0U;
            }
        } else {
            /* clear endpoint status_out status */
            USBD_STATUS_OUT_CLEAR(EP0);
        }
    } else {
        if (USBD_CONFIGURED == pudev->status) {
            pudev->class_data_handler(pudev, USBD_RX, ep_num);
        }
    }
    return USBD_OK;
}

/*!
    \brief      data in stage processing
    \param[in]  pudev: pointer to USB device instance
    \param[in]  ep_num: endpoint identifier(0..7)
    \param[out] none
    \retval     USB device operation status
*/
uint8_t  usbd_in_transaction (usbd_core_handle_struct *pudev, uint8_t ep_num)
{
    usb_ep_struct *ep = &pudev->in_ep[ep_num];

    if (0U == ep_num) {
        if (0U != pudev->ctl_count) {
            if (ep->trs_len > ep->maxpacket) {
                /* one data packet has been transmited, update trs_len */
                ep->trs_len -= ep->maxpacket;

                /* continue to transmit remain data */
                usbd_ep_tx (pudev, EP0_IN, ep->trs_buf, (uint16_t)ep->trs_len);

                usbd_ep_rx (pudev, 0, NULL, 0);
            } else {
#ifndef USB_DFU
                /* transmit length is maxpacket multiple, so send zero length packet */
                if ((0U == (ep->trs_len % ep->maxpacket)) && (ep->trs_len < pudev->ctl_count)) {
                    usbd_ep_tx (pudev, EP0_IN, NULL, 0U);

                    pudev->ctl_count = 0U;

                    usbd_ep_rx (pudev, 0, NULL, 0);
                } else
#endif /* USB_DFU */
                {
                    ep->trs_len = 0U;

                    if (USBD_CONFIGURED == pudev->status) {
                        pudev->class_data_handler(pudev, USBD_TX, EP0); 
                    }

                    USBD_CONTRL_STATUS_RX();

                    pudev->ctl_count = 0U;
                }
            }
        } else {
            if (0U != g_device_address) {
                USBD_REG_SET(USBD_DADDR, DADDR_USBEN | g_device_address);
                g_device_address = 0U;
            }
        }
    } else {
        ep->trs_len -= ep->trs_count;

        if (0U == ep->trs_len) {
            if (USBD_CONFIGURED == pudev->status) {
                pudev->class_data_handler(pudev, USBD_TX, ep_num);
            }
        } else {
            usbd_ep_tx(pudev, ep_num, ep->trs_buf, (uint16_t)ep->trs_len);
        }
    }

    return USBD_OK;
}

/*!
    \brief      handle USB standard device request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     USB device operation status
*/
uint8_t  usbd_standard_request (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    /* call device request handle function */
    (*standard_device_request[req->bRequest])(pudev, req);

    return USBD_OK;
}

/*!
    \brief      handle USB device class request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device class request
    \param[out] none
    \retval     USB device operation status
*/
uint8_t  usbd_device_class_request (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    usbd_status_enum ret;

    switch (pudev->status) {
    case USBD_CONFIGURED:
        if (LOWBYTE(req->wIndex) <= USBD_ITF_MAX_NUM) {
            /* call device class handle function */
            ret = (usbd_status_enum)(pudev->class_req_handler(pudev, req));

            if ((0U == req->wLength) && (USBD_OK == ret)) {
                /* no data stage */
                USBD_CONTRL_STATUS_TX();
            }
        } else {
            usbd_enum_error(pudev, req);
        }
        break;
    default:
        usbd_enum_error(pudev, req);
        break;
    }

    return USBD_OK;
}

/*!
    \brief      handle USB vendor request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB vendor request
    \param[out] none
    \retval     USB device operation status
*/
uint8_t  usbd_vendor_request (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    /* added by user */

    return USBD_OK;
}

/*!
    \brief      no operation, just for reserved
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_reserved (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    /* no operation */
}

#ifdef LPM_ENABLED

static uint8_t* usbd_bos_descriptor_get (usbd_core_handle_struct *pudev, uint16_t *pLen)
{
    *pLen = pudev->bos_desc[2] | ((uint16_t)pudev->bos_desc[3] << 8);

    return pudev->bos_desc;
}

#endif /* LPM_ENABLED */

/*!
    \brief      get the device descriptor
    \param[in]  pudev: pointer to USB device instance
    \param[in]  index: no use
    \param[out] pLen: data length pointer
    \retval     descriptor buffer pointer
*/
static uint8_t* usbd_device_descriptor_get (usbd_core_handle_struct *pudev, uint8_t index, uint16_t *pLen)
{
    *pLen = pudev->dev_desc[0];

    return pudev->dev_desc;
}

/*!
    \brief      get the configuration descriptor
    \brief[in]  pudev: pointer to USB device instance
    \brief[in]  index: no use
    \param[out] pLen: data length pointer
    \retval     descriptor buffer pointer
*/
static uint8_t* usbd_configuration_descriptor_get (usbd_core_handle_struct *pudev, uint8_t index, uint16_t *pLen)
{
    *pLen = pudev->config_desc[2];

    return pudev->config_desc;
}

/*!
    \brief      get string descriptor
    \param[in]  pudev: pointer to USB device instance
    \param[in]  index: string descriptor index
    \param[out] pLen: pointer to string length
    \retval     none
*/
static uint8_t* usbd_string_descriptor_get (usbd_core_handle_struct *pudev, uint8_t index, uint16_t *pLen)
{
    uint8_t *desc = pudev->strings[index];

    *pLen = desc[0];

    return desc;
}

/*!
    \brief      handle Get_Status request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_getstatus (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    uint8_t  ep_addr;
    uint16_t config_status = 0x0000U;
    uint16_t endp_status = 0x0000U;

    switch(req->bmRequestType & USB_REQ_RECIPIENT_MASK) {
    case USB_REQTYPE_DEVICE:
        switch (pudev->status) {
        case USBD_ADDRESSED:
        case USBD_CONFIGURED:

#ifdef USBD_SELF_POWERED
    config_status = USB_STATUS_SELF_POWERED;
#endif /* USBD_SELF_POWERED */

            if (pudev->remote_wakeup) {
                config_status |= USB_STATUS_REMOTE_WAKEUP;
            }

            usbd_ep_tx(pudev, EP0_IN, (uint8_t *)&config_status, 2U);
            break;
        default:
            break;
        }
        break;
    case USB_REQTYPE_INTERFACE:
        switch (pudev->status) {
        case USBD_ADDRESSED:
            usbd_enum_error(pudev, req);
            break;
        case USBD_CONFIGURED:
            if (LOWBYTE(req->wIndex) <= USBD_ITF_MAX_NUM) {
                usbd_ep_tx(pudev, EP0_IN, (uint8_t *)&config_status, 2U);
            } else {
                usbd_enum_error(pudev, req);
            }
            break;
        default:
            break;
        }
        break;
    case USB_REQTYPE_ENDPOINT:
        /* get enndpoint address */
        ep_addr = LOWBYTE(req->wIndex);

        switch (pudev->status) {
        case USBD_ADDRESSED:
            if (IS_NOT_EP0(ep_addr)) {
                usbd_enum_error(pudev, req);
            }
            break;
        case USBD_CONFIGURED:
            if ((ep_addr & 0x80U) == 0x80U) {
                if(pudev->in_ep[ep_addr & 0x7FU].stall) {
                    endp_status = 0x0001U;
                }
            } else {
                if (pudev->out_ep[ep_addr].stall) {
                    endp_status = 0x0001U;
                }
            }
            usbd_ep_tx(pudev, EP0_IN, (uint8_t *)&endp_status, 2U);
            break;

        default:
            break;
        }
        break;
    default:
        usbd_enum_error(pudev, req);
        break;
    }
}

/*!
    \brief      handle USB Clear_Feature request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_clearfeature (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    uint8_t ep_addr = 0U;

    switch (req->bmRequestType & USB_REQ_RECIPIENT_MASK) {
    case USB_REQTYPE_DEVICE:
        switch (pudev->status) {
        case USBD_ADDRESSED:
        case USBD_CONFIGURED:
            /* clear device remote wakeup feature */
            if (USB_FEATURE_REMOTE_WAKEUP == req->wValue) {
                pudev->remote_wakeup = 0U;
                pudev->class_req_handler(pudev, req);
                USBD_CONTRL_STATUS_TX();
            } else if (USB_FEATURE_TEST_MODE == req->wValue) {
                /* can not clear test_mode feature */
                usbd_enum_error(pudev, req);
            } else {
                /* no operation */
            }
            break;
        default:
            break;
        }
        break;
    case USB_REQTYPE_INTERFACE:
        switch (pudev->status) {
        case USBD_ADDRESSED:
            usbd_enum_error (pudev, req);
            break;
        case USBD_CONFIGURED:
            if (LOWBYTE(req->wIndex) <= USBD_ITF_MAX_NUM) {
                /* no operation */
            } else {
                usbd_enum_error(pudev, req);
            }
            break;
        default:
            break;
        }
        break;
    case USB_REQTYPE_ENDPOINT:
        /* get endpoint address */
        ep_addr = LOWBYTE(req->wIndex);

        switch (pudev->status) {
        case USBD_ADDRESSED:
            if (IS_NOT_EP0(ep_addr)) {
                usbd_enum_error(pudev, req);
            }
            break;
        case USBD_CONFIGURED:
            /* clear endpoint halt feature */
            if (USB_FEATURE_ENDP_HALT == req->wValue) {
                if (IS_NOT_EP0(ep_addr)) {
                    usbd_ep_clear_stall(pudev, ep_addr);
                }
            }

            pudev->class_req_handler(pudev, req);

            USBD_CONTRL_STATUS_TX();
            break;
        default:
            break;
        }
        break;
    default:
        usbd_enum_error(pudev, req);
        break;
    }
}

/*!
    \brief      handle USB Set_Feature request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_setfeature (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    uint8_t ep_addr = 0U;

    switch (req->bmRequestType & USB_REQ_RECIPIENT_MASK) {
    case USB_REQTYPE_DEVICE:
        switch (pudev->status) {
        case USBD_ADDRESSED:
        case USBD_CONFIGURED:
            /* set device remote wakeup feature */
            if (USB_FEATURE_REMOTE_WAKEUP == req->wValue) {
                pudev->remote_wakeup = 1U;

                USBD_CONTRL_STATUS_TX();
            }
            break;
        default:
            break;
        }
        break;
    case USB_REQTYPE_INTERFACE:
        switch (pudev->status) {
        case USBD_ADDRESSED:
            usbd_enum_error(pudev, req);
            break;
        case USBD_CONFIGURED:
            if (LOWBYTE(req->wIndex) <= USBD_ITF_MAX_NUM) {
                /* no operation */
            } else {
                usbd_enum_error(pudev, req);
            }
            break;
        default:
            break;
        }
        break;
    case USB_REQTYPE_ENDPOINT:
        /* get endpoint address */
        ep_addr = LOWBYTE(req->wIndex);

        switch (pudev->status) {
        case USBD_ADDRESSED:
            if (IS_NOT_EP0(ep_addr)) {
                usbd_enum_error(pudev, req);
            }
            break;
        case USBD_CONFIGURED:
            /* set endpoint halt feature */
            if (USB_FEATURE_ENDP_HALT == req->wValue) {
                if (IS_NOT_EP0(ep_addr)) {
                    usbd_ep_stall(pudev, ep_addr);
                }
            }
            USBD_CONTRL_STATUS_TX();
            break;
        default:
            break;
        }
        break;
    default:
        usbd_enum_error(pudev, req);
        break;
    }
}

/*!
    \brief      handle USB Set_Address request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_setaddress (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    if ((0U == req->wIndex) && (0U == req->wLength)) {
        g_device_address = (uint8_t)(req->wValue) & 0x7FU;

        if (USBD_CONFIGURED == pudev->status) {
            usbd_enum_error(pudev, req);
        } else {
            USBD_CONTRL_STATUS_TX();

            if (0U != g_device_address) {
                pudev->status  = USBD_ADDRESSED;
            } else {
                pudev->status  = USBD_DEFAULT;
            }
        }
    } else {
        usbd_enum_error(pudev, req);
    }
}

/*!
    \brief      handle USB Get_Descriptor request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_getdescriptor (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    if (USB_REQTYPE_DEVICE == (req->bmRequestType & USB_REQ_RECIPIENT_MASK)) {
        uint8_t *pbuf = NULL;
        uint8_t  desc_type = (uint8_t)(req->wValue >> 8);
        uint8_t  desc_index = (uint8_t)(req->wValue) & 0xFFU;
        uint16_t len = 0U;

        if ((desc_type <= 0x03U) && (desc_index <= 0x05U)) {
            /* call corresponding descriptor get function */
            pbuf = standard_descriptor_get[desc_type - 1U](pudev, desc_index, &len);
        } 
#ifdef LPM_ENABLED
        else if (USB_DESCTYPE_BOS == desc_type) {
            pbuf = usbd_bos_descriptor_get(pudev, &len);
        }
#endif /* LPM_ENABLED */
        else {
            usbd_enum_error(pudev, req);
        }

        if ((0U != len) && (0U != req->wLength)) {
            len = MIN(len, req->wLength);

            usbd_ep_tx (pudev, EP0_IN, pbuf, len);
        }
    } else if (USB_REQTYPE_INTERFACE == (req->bmRequestType & USB_REQ_RECIPIENT_MASK)) {
        if (NULL != pudev->class_req_handler) {
            /* get device class special descriptor */
            pudev->class_req_handler(pudev, req);
        }
    } else {
        
    }
}

/*!
    \brief      handle USB Set_Descriptor request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_setdescriptor (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    /* no handle */
}

/*!
    \brief      handle USB Get_Configuration request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_getconfiguration (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    uint32_t usbd_default_config = 0U;

    if (req->wLength != 1) {
        usbd_enum_error(pudev, req);
    } else {
        switch (pudev->status) {
        case USBD_ADDRESSED:
            usbd_ep_tx (pudev, EP0_IN, (uint8_t *)&usbd_default_config, 1U);
            break;
        case USBD_CONFIGURED:
            usbd_ep_tx (pudev, EP0_IN, &pudev->config_num, 1);
            break;
        default:
            usbd_enum_error(pudev, req);
            break;
        }
    }
}

/*!
    \brief      handle USB Set_Configuration request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_setconfiguration (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    static uint8_t  cfgidx;

    cfgidx = (uint8_t)(req->wValue);

    if (cfgidx > USBD_CFG_MAX_NUM) {
        usbd_enum_error(pudev, req);
    } else {
        switch (pudev->status) {
        case USBD_ADDRESSED:
            if (cfgidx){
                pudev->config_num = cfgidx;
                pudev->status = USBD_CONFIGURED;
                pudev->class_init(pudev, cfgidx);
                USBD_CONTRL_STATUS_TX();
            } else {
                USBD_CONTRL_STATUS_TX();
            }
            break;
        case USBD_CONFIGURED:
            if (0U == cfgidx) {
                pudev->status = USBD_ADDRESSED;
                pudev->config_num = cfgidx;
                pudev->class_deinit(pudev, cfgidx);
                USBD_CONTRL_STATUS_TX();
            } else if (cfgidx != pudev->config_num) {
                /* clear old configuration */
                pudev->class_deinit(pudev, pudev->config_num);

                /* set new configuration */
                pudev->config_num = cfgidx;
                pudev->class_init(pudev, cfgidx);
                USBD_CONTRL_STATUS_TX();
            } else {
                USBD_CONTRL_STATUS_TX();
            }
            break;
        default:
            break;
        }
    }
}

/*!
    \brief      handle USB Get_Interface request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_getinterface (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    switch (pudev->status) {
    case USBD_ADDRESSED:
        usbd_enum_error(pudev, req);
        break;
    case USBD_CONFIGURED:
        if (LOWBYTE(req->wIndex) <= USBD_ITF_MAX_NUM) {
            if (NULL != pudev->class_req_handler) {
                pudev->class_req_handler(pudev, req);
            }
        } else {
            usbd_enum_error(pudev, req);
        }
        break;
    default:
        break;
    }
}

/*!
    \brief      handle USB Set_Interface request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_setinterface (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    switch (pudev->status) {
    case USBD_ADDRESSED:
        usbd_enum_error(pudev, req);
        break;
    case USBD_CONFIGURED:
        if (LOWBYTE(req->wIndex) <= USBD_ITF_MAX_NUM) {
            if (NULL != pudev->class_req_handler) {
                pudev->class_req_handler(pudev, req);
            }

            USBD_CONTRL_STATUS_TX();
        } else {
            usbd_enum_error(pudev, req);
        }
        break;
    default:
        break;
    }
}

/*!
    \brief      handle USB SynchFrame request
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
static void  usbd_synchframe (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    /* no handle */
}

/*!
    \brief      decode setup data packet
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
void  usbd_setup_request_parse (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    uint8_t *setup_data = pudev->setup_packet;

    req->bmRequestType = *setup_data;
    req->bRequest = *(uint8_t *)(setup_data + 1U);
    req->wValue = SWAPBYTE (setup_data + 2U);
    req->wIndex = SWAPBYTE (setup_data + 4U);
    req->wLength = SWAPBYTE (setup_data + 6U);

    pudev->ctl_count = req->wLength;
}

/*!
    \brief      handle USB enumeration error event
    \param[in]  pudev: pointer to USB device instance
    \param[in]  req: pointer to USB device request
    \param[out] none
    \retval     none
*/
void  usbd_enum_error (usbd_core_handle_struct *pudev, usb_device_req_struct *req)
{
    usbd_ep_stall(pudev, EP0);
}
