rt-thread-official/bsp/gd32450z-eval/Libraries/GD32F4xx_usb_driver/Source/usbd_int.c

/*!
    \file  usbd_int.c
    \brief USB device mode interrupt routines
*/

/*
    Copyright (C) 2016 GigaDevice

    2016-08-15, V1.0.0, firmware for GD32F4xx
*/

#include "usbd_int.h"
#include "usbd_std.h"

/* interrupt handlers */
static uint32_t usbd_intf_outep               (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_inep                (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_earlysuspend        (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_suspend             (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_resume              (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_sof                 (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_rxfifo              (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_reset               (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_enumfinish          (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_isoinincomplete     (usb_core_handle_struct *pudev);
static uint32_t usbd_intf_isooutincomplete    (usb_core_handle_struct *pudev);

static uint32_t usbd_emptytxfifo_write        (usb_core_handle_struct *pudev, uint8_t ep_num);

#ifdef VBUS_SENSING_ENABLED

    static uint32_t usbd_intf_otg             (usb_core_handle_struct *pudev);
    static uint32_t usbd_intf_sessionrequest  (usb_core_handle_struct *pudev);

#endif

static usb_speed_enum USB_SPEED[4] = {
    [DSTAT_ENUMSPD_HS_PHY_30MHZ_OR_60MHZ] = USB_SPEED_HIGH,
    [DSTAT_ENUMSPD_FS_PHY_30MHZ_OR_60MHZ] = USB_SPEED_FULL,
    [DSTAT_ENUMSPD_FS_PHY_48MHZ] = USB_SPEED_FULL,
    [DSTAT_ENUMSPD_LS_PHY_6MHZ] = USB_SPEED_LOW
};

static const uint8_t EP0_MAXLEN[4] = {
    [DSTAT_ENUMSPD_HS_PHY_30MHZ_OR_60MHZ] = EP0MPL_64,
    [DSTAT_ENUMSPD_FS_PHY_30MHZ_OR_60MHZ] = EP0MPL_64,
    [DSTAT_ENUMSPD_FS_PHY_48MHZ] = EP0MPL_64,
    [DSTAT_ENUMSPD_LS_PHY_6MHZ] = EP0MPL_8
};

#ifdef USBHS_DEDICATED_EP1_ENABLED

/*!
    \brief      USB dedicated OUT endpoint 1 interrupt service routine handler
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
uint32_t USBD_EP1OUT_ISR_Handler (usb_core_handle_struct *pudev)
{
    uint32_t out_endp_int = 0;
    uint32_t out_endp_size = 0;

    out_endp_int = USB_DOEPxINTF(1);
    out_endp_int &= USB_DOEP1INTEN;

    /* transfer complete */
    if (out_endp_int & DOEPINTF_TF) {
        /* clear the interrupt bit */
        USB_DOEPxINTF(1) = DOEPINTF_TF;

        if (1U == pudev->cfg.dma_enable) {
            out_endp_size = USB_DOEPxLEN(1);

            /* handle more than one single MPS size packet */
            pudev->dev.out_ep[1].xfer_count = pudev->dev.out_ep[1].endp_mps - \
                                              (out_endp_size & DOEPLEN_TLEN);
        }

        /* inform upper layer: data ready */

        /* receive complete */
        usbd_out_transaction(pudev, 1);
    }

    /* endpoint disable interrupt */
    if (out_endp_int & DOEPINTF_EPDIS) {
        /* clear the interrupt bit */
        USB_DOEPxINTF(1) = DOEPINTF_EPDIS;
    }

    return 1;
}

/*!
    \brief      USB dedicated IN endpoint 1 interrupt service routine handler
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
uint32_t USBD_EP1IN_ISR_Handler (usb_core_handle_struct *pudev)
{
    uint32_t fifoemptymask = 0, mask = 0;
    uint32_t in_endp_int = 0;

    mask = USB_DIEP1INTEN;
    mask |= ((USB_DIEPFEINTEN >> 1) & 0x01) << 7;
    in_endp_int = USB_DIEPxINTF(1) & mask;

    if (in_endp_int & DIEPINTF_TF) {
        fifoemptymask = 0x01 << 1;
        USB_DIEPFEINTEN &= ~fifoemptymask;

        USB_DIEPxINTF(1) = DIEPINTF_TF;

        /* transmit complete */
        usbd_in_transaction(pudev , 1);
    }

    if (in_endp_int & DIEPINTF_EPDIS) {
        USB_DIEPxINTF(1) = DIEPINTF_EPDIS;
    }

    if (in_endp_int & DIEPINTF_CITO) {
        USB_DIEPxINTF(1) = DIEPINTF_CITO;
    }

    if (in_endp_int & DIEPINTF_EPTXFUD) {
        USB_DIEPxINTF(1) = DIEPINTF_EPTXFUD;
    }

    if (in_endp_int & DIEPINTF_IEPNE) {
        USB_DIEPxINTF(1) = DIEPINTF_IEPNE;
    }

    if (in_endp_int & DIEPINTF_TXFE) {
        usbd_emptytxfifo_write(pudev, 1);

        USB_DIEPxINTF(1) = DIEPINTF_IEPNE;
    }

    return 1;
}

#endif


/*!
    \brief      USB device-mode interrupts global service routine handler
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
uint32_t usbd_isr (usb_core_handle_struct *pudev)
{
    uint32_t retval = 0U;
    uint32_t int_status = 0U, gintf = USB_GINTF, ginten = USB_GINTEN;

    /* ensure the core is in device mode */
    if (DEVICE_MODE == USB_CURRENT_MODE_GET()) {
        int_status = gintf & ginten;

        /* there are no interrupts, avoid spurious interrupt */
        if (!int_status) {
            return 0U;
        }

        /* OUT endpoints interrupts */
        if (int_status & GINTF_OEPIF) {
            retval |= usbd_intf_outep(pudev);
        }

        /* IN endpoints interrupts */
        if (int_status & GINTF_IEPIF) {
            retval |= usbd_intf_inep(pudev);
        }

        /* mode mismatch interrupt */
        if (int_status & GINTF_MFIF) {
            /* clear interrupt */
            USB_GINTF = GINTF_MFIF;
        }

        /* early suspend interrupt */
        if (int_status & GINTF_ESP) {
            retval |= usbd_intf_earlysuspend(pudev);
        }

        /* suspend interrupt */
        if (int_status & GINTF_SP) {
            retval |= usbd_intf_suspend(pudev);
        }

        /* wakeup interrupt */
        if (int_status & GINTF_WKUPIF) {
            retval |= usbd_intf_resume(pudev);
        }

        /* start of frame interrupt */
        if (int_status & GINTF_SOF) {
            retval |= usbd_intf_sof(pudev);
        }

        /* reveive fifo not empty interrupt */
        if (int_status & GINTF_RXFNEIF) {
            retval |= usbd_intf_rxfifo(pudev);
        }

        /* USB reset interrupt */
        if (int_status & GINTF_RST) {
            retval |= usbd_intf_reset(pudev);
        }

        /* enumeration has been finished interrupt */
        if (int_status & GINTF_ENUMFIF) {
            retval |= usbd_intf_enumfinish(pudev);
        }

        /* incomplete synchronization in transfer interrupt*/
        if (int_status & GINTF_ISOINCIF) {
            retval |= usbd_intf_isoinincomplete(pudev);
        }

        /* incomplete synchronization out transfer interrupt*/
        if (int_status & GINTF_ISOONCIF) {
            retval |= usbd_intf_isooutincomplete(pudev);
        }

#ifdef VBUS_SENSING_ENABLED

        /* session request interrupt */
        if (int_status & GINTF_SESIF) {
            retval |= usbd_intf_sessionrequest(pudev);
        }

        /* OTG mode interrupt */
        if (int_status & GINTF_OTGIF) {
            retval |= usbd_intf_otg(pudev);
        }
#endif /* VBUS_SENSING_ENABLED */
    }

    return retval;
}

/*!
    \brief      indicates that an OUT endpoint has a pending interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_outep (usb_core_handle_struct *pudev)
{
    uint8_t endp_num = 0U;
    uint32_t endp_intr = 0U;

    __IO uint32_t out_endp_intr = 0U;

    /* read in the device interrupt bits */
    USB_DAOEP_INTR_READ(endp_intr);

    while (endp_intr) {
        if (endp_intr & 0x1U) {
            USB_DOEP_INTR_READ(out_endp_intr, (uint16_t)endp_num);

            /* transfer complete interrupt */
            if (out_endp_intr & DOEPINTF_TF) {
                USB_DOEPxINTF((uint16_t)endp_num) = DOEPINTF_TF;

                if (1U == pudev->cfg.dma_enable) {
                    uint32_t xfer_size = USB_DOEPxLEN((uint16_t)endp_num) & DOEPLEN_TLEN;

                    pudev->dev.out_ep[endp_num].xfer_count = pudev->dev.out_ep[endp_num].endp_mps - \
                                                             xfer_size;
                }

                /* data receive is completed */
                usbd_out_transaction(pudev, endp_num);
   
                if (1U == pudev->cfg.dma_enable) {
                    if ((0U == endp_num) && (USB_CTRL_STATUS_OUT == pudev->dev.ctl_status)) {
                        /* prepare to receive more setup packets */
                        usb_ep0_startout(pudev);
                    }
                }
            }

            /* endpoint disable interrupt */
            if (out_endp_intr & DOEPINTF_EPDIS) {
                USB_DOEPxINTF((uint16_t)endp_num) = DOEPINTF_EPDIS;
            }

            /* setup phase finished interrupt (just for control endpoints) */
            if (out_endp_intr & DOEPINTF_STPF) {
                /* setup phase is completed */
                usbd_setup_transaction(pudev);

                USB_DOEPxINTF((uint16_t)endp_num) = DOEPINTF_STPF;
            }

            /* back to back setup packets received */
            if (out_endp_intr & DOEPINTF_BTBSTP) {
                USB_DOEPxINTF((uint16_t)endp_num) = DOEPINTF_BTBSTP;
            }
        }

        endp_num ++;
        endp_intr >>= 1;
    }

    return 1U;
}

/*!
    \brief      indicates that an IN endpoint has a pending interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_inep(usb_core_handle_struct *pudev)
{
    uint8_t endp_num = 0U;
    uint32_t endp_intr = 0U;

    __IO uint32_t in_endp_intr = 0U;

    /* get all in endpoints which have interrupts */
    USB_DAIEP_INTR_READ(endp_intr);

    while (endp_intr) {
        if (endp_intr & 0x1U) {
            USB_DIEP_INTR_READ(in_endp_intr, (uint16_t)endp_num);

            if (in_endp_intr & DIEPINTF_TF) {
                /* disable the fifo empty interrupt for the endpoint */
                USB_DIEPFEINTEN &= ~(0x1U << endp_num);

                USB_DIEPxINTF((uint16_t)endp_num) = DIEPINTF_TF;

                /* data transmittion is completed */
                usbd_in_transaction(pudev, endp_num);

                if (1U == pudev->cfg.dma_enable) {
                    if ((0U == endp_num) && (USB_CTRL_STATUS_IN == pudev->dev.ctl_status)) {
                        /* prepare to receive more setup packets */
                        usb_ep0_startout(pudev);
                    }
                }
            }

            if (in_endp_intr & DIEPINTF_CITO) {
                USB_DIEPxINTF((uint16_t)endp_num) = DIEPINTF_CITO;
            }

            if (in_endp_intr & DIEPINTF_IEPNE) {
                USB_DIEPxINTF((uint16_t)endp_num) = DIEPINTF_IEPNE;
            }

            if (in_endp_intr & DIEPINTF_EPDIS) {
                USB_DIEPxINTF((uint16_t)endp_num) = DIEPINTF_EPDIS;
            }

            if (in_endp_intr & DIEPINTF_TXFE) {
                usbd_emptytxfifo_write(pudev, endp_num);
                USB_DIEPxINTF((uint16_t)endp_num) = DIEPINTF_TXFE;
            }
        }

        endp_num ++;
        endp_intr >>= 1;
    }

    return 1U;
}

/*!
    \brief      indicates that early SUSPEND state has been detected on the USB
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_earlysuspend (usb_core_handle_struct *pudev)
{
    USB_GINTEN &= ~GINTEN_ESPIE;
    USB_GINTF = GINTF_ESP;

    return 1U;
}

/*!
    \brief      indicates that SUSPEND state has been detected on the USB
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_suspend(usb_core_handle_struct *pudev)
{
    __IO uint8_t low_power = pudev->cfg.low_power;
    __IO uint8_t suspend = (uint8_t)(USB_DSTAT & DSTAT_SPST);
    __IO uint8_t is_configured = (pudev->dev.status == USB_STATUS_CONFIGURED)? 1U : 0U;

    pudev->dev.prev_status = pudev->dev.status;
    pudev->dev.status = USB_STATUS_SUSPENDED;

    if (low_power && suspend && is_configured) {
        /* switch-off the otg clocks */
        USB_PWRCLKCTL |= PWRCLKCTL_SUCLK | PWRCLKCTL_SHCLK;

        /* enter DEEP_SLEEP mode with LDO in low power mode */
        pmu_to_deepsleepmode(PMU_LDO_LOWPOWER, WFI_CMD);
    }

    /* clear interrupt */
    USB_GINTF = GINTF_SP;

    return 1U;
}

/*!
    \brief      indicates that the USB controller has detected a resume or remote Wake-up sequence
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_resume (usb_core_handle_struct *pudev)
{
    pudev->dev.status = pudev->dev.prev_status;
    pudev->dev.status = USB_STATUS_CONFIGURED;

    /* clear interrupt */
    USB_GINTF = GINTF_WKUPIF;

    return 1U;
}

/*!
    \brief      handle the SOF interrupts
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_sof(usb_core_handle_struct *pudev)
{
//    USBD_DCD_INT_fops->SOF(pudev);

    USB_GINTF = GINTF_SOF;

    return 1U;
}

/*!
    \brief      handle the Rx status queue level interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     operation status
*/
static uint32_t usbd_intf_rxfifo (usb_core_handle_struct *pudev)
{
    usb_ep_struct *ep;
    uint8_t data_pid = 0U, endp_num = 0U;
    uint32_t bcount = 0U;

    /* get the status from the top of the fifo (must be read to a variable) */
    __IO uint32_t rx_status = USB_GRSTATP;

    /* disable the rx fifo non-empty interrupt */
    USB_GINTEN &= ~GINTEN_RXFNEIE;

    endp_num = (uint8_t)(rx_status & GRSTATP_EPNUM);
    bcount = (rx_status & GRSTATP_BCOUNT) >> 4U;
    data_pid = (uint8_t)((rx_status & GRSTATP_DPID) >> 15U);

    if ((endp_num == 1) && ((*(uint32_t *)0x40040B30 & 0x1FF80000) == 0)) {
        *(uint32_t *)0x40040B20 = ((*(uint32_t *)0x40040B20 | 0x08000000) & 0x3FFFFFFF);
    }

    ep = &pudev->dev.out_ep[endp_num];

    switch ((rx_status & GRSTATP_RPCKST) >> 17U) {
        case RXSTAT_GOUT_NAK:
            if(0U != bcount) {
                return 0U;
            }
            break;
        case RXSTAT_DATA_UPDT:
            if (bcount > 0U) {
                usb_fifo_read(ep->xfer_buff, (uint16_t)bcount);
                ep->xfer_buff += bcount;
                ep->xfer_count += bcount;
            }
            break;
        case RXSTAT_XFER_COMP:
            if (0U != bcount) {
                return 0U;
            }
            break;
        case RXSTAT_SETUP_COMP:
            if(0U != bcount) {
                return 0U;
            }
            break;
        case RXSTAT_SETUP_UPDT:
            if ((0U == endp_num) && (8U == bcount) && (DPID_DATA0 == data_pid)) {
                /* copy the setup packet received in fifo into the setup buffer in ram */
                usb_fifo_read(pudev->dev.setup_packet, 8U);

                ep->xfer_count += bcount;
            }
            break;
        default:
            break;
    }

    /* enable the Rx fifo non-empty interrupt */
    USB_GINTEN |= GINTEN_RXFNEIE;

    return 1U;
}

/*!
    \brief      handle USB reset interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     status
*/
static uint32_t usbd_intf_reset(usb_core_handle_struct *pudev)
{
    uint8_t i = 0U;
    usb_ep_struct *ep;

    /* clear the remote wakeup signaling */
    USB_DCTL &= ~DCTL_RWKUP;

    /* flush the tx fifo */
    usb_txfifo_flush(pudev, 0U);

    for (i = 0U; i < pudev->cfg.dev_endp_num; i++) {
        USB_DIEPxINTF((uint16_t)i) = 0xFFU;
        USB_DOEPxINTF((uint16_t)i) = 0xFFU;
    }

    /* clear all pending device endpoint interrupts */
    USB_DAEPINT = 0xFFFFFFFF;

    /* enable endpoint 0 interrupts */
    USB_DAEPINTEN &= ~DAEPINTEN_OEPIE;
    USB_DAEPINTEN &= ~DAEPINTEN_IEPIE;
    USB_DAEPINTEN = (1U << 16) | 1U;

    /* enable out endpoint interrupts */
    USB_DOEPINTEN = DOEPINTEN_STPFEN | DOEPINTEN_TFEN | DOEPINTEN_EPDISEN;

#ifdef USBHS_DEDICATED_EP1_ENABLED
    USB_DOEP1INTEN = DOEPINTEN_STPFEN | DOEPINTEN_TFEN | DOEPINTEN_EPDISEN;
#endif

    /* enable in endpoint interrupts */
    USB_DIEPINTEN = DIEPINTEN_TFEN | DIEPINTEN_CITOEN | DIEPINTEN_EPDISEN;

#ifdef USBHS_DEDICATED_EP1_ENABLED
    USB_DIEP1INTEN = DIEPINTEN_TFEN | DIEPINTEN_CITOEN | DIEPINTEN_EPDISEN;
#endif

    /* reset device address */
    USB_DCFG &= ~DCFG_DAR;
    USB_DCFG |= 0U << 4U;

    /* configure endpoint 0 to receive setup packets */
    usb_ep0_startout(pudev);

    /* clear usb reset interrupt */
    USB_GINTF = GINTF_RST;

    /* open EP0 IN */
    ep = &pudev->dev.in_ep[0];

    USB_DIEPxCTL(0U) &= ~DIEP0CTL_MPL;
    USB_DIEPxCTL(0U) &= ~DIEPCTL_EPTYPE;
    USB_DIEPxCTL(0U) &= ~DIEPCTL_TXFNUM;

    if (!(USB_DIEPxCTL(0U) & DIEPCTL_EPACT)) {
        USB_DIEPxCTL(0U) |= USB_MAX_EP0_SIZE;
        USB_DIEPxCTL(0U) |= (USB_EPTYPE_CTRL << 18U);
        USB_DIEPxCTL(0U) |= DIEP0CTL_EPACT;
    }

    ep->endp_mps = USB_MAX_EP0_SIZE;
    ep->endp_type = USB_EPTYPE_CTRL;

    /* open EP0 OUT */
    ep = &pudev->dev.out_ep[0];

    USB_DOEPxCTL(0U) &= ~DOEP0CTL_MPL;
    USB_DOEPxCTL(0U) &= ~DOEPCTL_EPTYPE;

    if (!(USB_DOEPxCTL(0U) & DOEPCTL_EPACT)) {
        USB_DOEPxCTL(0U) |= USB_MAX_EP0_SIZE;
        USB_DOEPxCTL(0U) |= (USB_EPTYPE_CTRL << 18U);
        USB_DOEPxCTL(0U) |= DOEP0CTL_EPACT;
    }

    ep->endp_mps = USB_MAX_EP0_SIZE;
    ep->endp_type = USB_EPTYPE_CTRL;

    pudev->dev.status = USB_STATUS_DEFAULT;

    return 1U;
}

/*!
    \brief      handle enumeration finish interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     status
*/
static uint32_t usbd_intf_enumfinish(usb_core_handle_struct *pudev)
{
    uint8_t enum_speed = (uint8_t)((USB_DSTAT & DSTAT_ES) >> 1U);

    /* set the max packet size of devie in endpoint based on the enumeration speed */
    USB_DIEPxCTL(0U) |= EP0_MAXLEN[enum_speed];

    /* clear global IN NAK */
    USB_DCTL &= ~DCTL_CGINAK;
    USB_DCTL |= DCTL_CGINAK;

    /* set USB turn-around time based on device speed and PHY interface */
    if (USB_SPEED_HIGH == USB_SPEED[enum_speed]) {
        pudev->cfg.core_speed = USB_CORE_SPEED_HIGH;
        pudev->cfg.max_packet_size = USBHS_MAX_PACKET_SIZE;

        USB_GUSBCS &= ~GUSBCS_UTT;
        USB_GUSBCS |= 0x09U << 10;
    } else {
        pudev->cfg.core_speed = USB_CORE_SPEED_FULL;
        pudev->cfg.max_packet_size = USBFS_MAX_PACKET_SIZE;

        USB_GUSBCS &= ~GUSBCS_UTT;
        USB_GUSBCS |= 0x05U << 10;
    }

    /* clear interrupt */
    USB_GINTF = GINTF_ENUMFIF;

    return 1U;
}

/*!
    \brief      handle the ISO IN incomplete interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     status
*/
static uint32_t usbd_intf_isoinincomplete(usb_core_handle_struct *pudev)
{
//    USBD_DCD_INT_fops->IsoINIncomplete (pudev);

    /* clear interrupt */
    USB_GINTF = GINTF_ISOINCIF;

    return 1U;
}

/*!
    \brief      handle the ISO OUT incomplete interrupt
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     status
*/
static uint32_t usbd_intf_isooutincomplete(usb_core_handle_struct *pudev)
{
//    USBD_DCD_INT_fops->IsoOUTIncomplete (pudev);

    /* clear interrupt */
    USB_GINTF = GINTF_ISOONCIF;

    return 1U;
}

/*!
    \brief      check FIFO for the next packet to be loaded
    \param[in]  pudev: pointer to usb device instance
    \param[in]  ep_id: endpoint identifier which is in (0..3)
    \param[out] none
    \retval     status
*/
static uint32_t usbd_emptytxfifo_write(usb_core_handle_struct *pudev, uint8_t ep_num)
{
    uint32_t len = 0U, word_len = 0U;
    usb_ep_struct *ep;

    ep = &pudev->dev.in_ep[ep_num];
    len = ep->xfer_len - ep->xfer_count;

    if (len > ep->endp_mps) {
        len = ep->endp_mps;
    }

    word_len = (len + 3U) / 4U;

    while (((USB_DIEPxTFSTAT((uint16_t)ep_num) & DIEPTFSTAT_IEPTFS) > word_len) &&
            (ep->xfer_count < ep->xfer_len)) {
        /* write the FIFO */
        len = ep->xfer_len - ep->xfer_count;

        if (len > ep->endp_mps) {
            len = ep->endp_mps;
        }

        word_len = (len + 3U) / 4U;

        usb_fifo_write (ep->xfer_buff, ep_num, (uint16_t)len);

        ep->xfer_buff += len;
        ep->xfer_count += len;
    }

    return 1U;
}

#ifdef VBUS_SENSING_ENABLED

/*!
    \brief      indicates that the USB_OTG controller has detected a connection
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     status
*/
static uint32_t usbd_intf_sessionrequest(usb_core_handle_struct *pudev)
{
    pudev->dev.connection_status = 1U;

    /* clear the interrupt bit */
    USB_GINTF = GINTF_SESIF;

    return 1;
}

/*!
    \brief      indicates that the USB_OTG controller has detected an OTG event
    \param[in]  pudev: pointer to usb device instance
    \param[out] none
    \retval     status
*/
static uint32_t usbd_intf_otg(usb_core_handle_struct *pudev)
{
    if (USB_GOTGINTF & GOTGINTF_SESEND) {
        pudev->dev.class_deinit(pudev, 0);
        pudev->dev.connection_status = 0;
    }

    /* clear OTG interrupt */
    USB_GOTGINTF |= GOTGINTF_SESEND;

    return 1;
}

#endif /* VBUS_SENSING_ENABLED */