PS100/Libraries/GD32F10x_usbfs_driver/Source/usbh_core.c

/*!
    \file  usbh_core.c 
    \brief this file implements the functions for the core state machine process

    \version 2014-12-26, V1.0.0, firmware for GD32F10x
    \version 2017-06-20, V2.0.0, firmware for GD32F10x
    \version 2018-07-31, V2.1.0, firmware for GD32F10x
*/

/*
    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 "usbh_hcs.h"
#include "usbh_core.h"
#include "usbh_int.h"
#include "stdio.h"
#include "usbh_std.h"
#include "usbh_ctrl.h"
#include "usb_core.h"

extern class_polling_fun_cb_struct class_polling_cb;

uint8_t usbh_sof          (usb_core_handle_struct *pudev);
uint8_t usbh_connected    (usb_core_handle_struct *pudev);
uint8_t usbh_disconnected (usb_core_handle_struct *pudev);

usbh_hcd_int_cb_struct usbh_hcd_int_cb = 
{
    usbh_sof,
    usbh_connected,
    usbh_disconnected,
};

usbh_hcd_int_cb_struct  *usbh_hcd_int_fops = &usbh_hcd_int_cb;
extern usbh_state_handle_struct usbh_state_core;

static void host_idle_handle             (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_dev_attached_handle     (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_dev_detached_handle     (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_detect_dev_speed_handle (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_enum_handle             (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_class_request_handle    (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_class_handle            (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_user_input_handle       (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_suspended_handle        (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);
static void host_error_handle            (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate);

static usbh_status_enum class_req_state_polling_fun  (usb_core_handle_struct *pudev, usbh_host_struct *puhost, void *pustate);
static usbh_status_enum class_state_polling_fun      (usb_core_handle_struct *pudev, usbh_host_struct *puhost, void *pustate);

/* the host state handle function array */
void (*host_state_handle[]) (usb_core_handle_struct *pudev, usbh_host_struct *puhost, usbh_state_handle_struct *pustate) =
{
    host_idle_handle,
    host_dev_attached_handle,
    host_dev_detached_handle,
    host_detect_dev_speed_handle,
    host_enum_handle,
    host_class_request_handle,
    host_class_handle,
    host_user_input_handle,
    host_suspended_handle,
    host_error_handle,
};

/* the host state handle table */
state_table_struct host_handle_table[HOST_HANDLE_TABLE_SIZE] = 
{
    /* the current state  the current event        the next state        the event function */
    {HOST_IDLE,           HOST_EVENT_ATTACHED,     HOST_DEV_ATTACHED,    only_state_move     },
    {HOST_DEV_ATTACHED,   HOST_EVENT_ENUM,         HOST_ENUMERATION,     only_state_move     },
    {HOST_ENUMERATION,    HOST_EVENT_USER_INPUT,   HOST_USER_INPUT,      only_state_move     },
    {HOST_USER_INPUT,     HOST_EVENT_CLASS_REQ,    HOST_CLASS_REQUEST,   only_state_move     },
    {HOST_CLASS_REQUEST,  HOST_EVENT_CLASS,        HOST_CLASS,           only_state_move     },
    {HOST_CLASS,          HOST_EVENT_ERROR,        HOST_ERROR,           only_state_move     },
    {HOST_ERROR,          HOST_EVENT_IDLE,         HOST_IDLE,            only_state_move     },
    {HOST_DEV_DETACHED,   HOST_EVENT_IDLE,         HOST_IDLE,            only_state_move     },
    {HOST_CLASS_REQUEST,  HOST_EVENT_ERROR,        HOST_ERROR,           only_state_move     },
};

/*!
    \brief      the polling function of host state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
usbh_status_enum host_state_polling_fun (usb_core_handle_struct *pudev, 
                                         usbh_host_struct *puhost, 
                                         void *pustate)
{
    usbh_state_handle_struct *p_state = (usbh_state_handle_struct *)pustate;

    scd_begin(p_state, HOST_FSM_ID);

    if (-1 == p_state->usbh_current_state_stack_top) {
        uint8_t cur_state = p_state->usbh_current_state;

        if ((0U == hcd_is_device_connected(pudev)) && (HOST_IDLE != cur_state)) {
            if (HOST_DEV_DETACHED != cur_state) {
                p_state->usbh_current_state = HOST_DEV_DETACHED;
                cur_state = HOST_DEV_DETACHED;
            }
        }

        host_state_handle[cur_state](pudev, puhost, p_state);
    } else {
        uint8_t stack0_state = p_state->stack[0].state;

        if ((0U == hcd_is_device_connected(pudev)) && (HOST_IDLE != stack0_state)) {
            if (HOST_DEV_DETACHED != stack0_state) {
                p_state->stack[0].state = HOST_DEV_DETACHED;
                stack0_state = HOST_DEV_DETACHED;
                p_state->usbh_current_state = HOST_DEV_DETACHED;
            }
        }

        host_state_handle[stack0_state](pudev, puhost, p_state);
    }

    return USBH_OK;
}

/*!
    \brief      the handle function of HOST_IDLE state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_idle_handle (usb_core_handle_struct *pudev, 
                              usbh_host_struct *puhost, 
                              usbh_state_handle_struct *pustate)
{
    if (hcd_is_device_connected(pudev)) {
        scd_event_handle(pudev, puhost, pustate, HOST_EVENT_ATTACHED, pustate->usbh_current_state);

        if ((void *)0 != pudev->mdelay) {
            pudev->mdelay(100U);
        }
    }
}

/*!
    \brief      the handle function of HOST_DEV_ATTACHED state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_dev_attached_handle (usb_core_handle_struct *pudev, 
                                      usbh_host_struct *puhost, 
                                      usbh_state_handle_struct *pustate)
{
    puhost->usr_cb->device_connected();
    puhost->control.hc_out_num = usbh_channel_alloc(pudev, 0x00U);
    puhost->control.hc_in_num = usbh_channel_alloc(pudev, 0x80U);

    /* reset usb device */
    if (0U == usb_port_reset(pudev)) {
        puhost->usr_cb->device_reset();

        /* wait for USB USBH_ISR_PrtEnDisableChange()
         * host is now ready to start the enumeration
         */
        puhost->device.speed = (uint8_t)USB_CURRENT_SPEED_GET();
        puhost->usr_cb->device_speed_detected(puhost->device.speed);

        /* open in control pipes */
        usbh_channel_open (pudev,
                           puhost->control.hc_in_num,
                           puhost->device.address,
                           puhost->device.speed,
                           USB_EPTYPE_CTRL,
                           (uint16_t)puhost->control.ep0_size);

        /* open out control pipes */
        usbh_channel_open (pudev,
                           puhost->control.hc_out_num,
                           puhost->device.address,
                           puhost->device.speed,
                           USB_EPTYPE_CTRL,
                           (uint16_t)puhost->control.ep0_size);

        scd_event_handle(pudev, puhost, pustate, HOST_EVENT_ENUM, pustate->usbh_current_state);
    }
}

/*!
    \brief      the handle function of HOST_ENUMERATION state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_enum_handle (usb_core_handle_struct *pudev, 
                              usbh_host_struct *puhost, 
                              usbh_state_handle_struct *pustate)
{
    if (USBH_OK == enum_state_polling_fun(pudev, puhost, pustate)) {
        puhost->usr_cb->enumeration_finish();
        scd_event_handle(pudev, 
                         puhost, 
                         pustate, 
                         HOST_EVENT_USER_INPUT, 
                         pustate->usbh_current_state);
    }
}

/*!
    \brief      the handle function of HOST_USER_INPUT state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_user_input_handle (usb_core_handle_struct *pudev, 
                                    usbh_host_struct *puhost, 
                                    usbh_state_handle_struct *pustate)
{
    if (USBH_USER_RESP_OK == puhost->usr_cb->user_input()) {
        if (USBH_OK == (puhost->class_init(pudev, puhost))) {
            scd_event_handle(pudev, 
                             puhost, 
                             pustate, 
                             HOST_EVENT_CLASS_REQ, 
                             pustate->usbh_current_state);
        }
    }
}

/*!
    \brief      the handle function of HOST_CLASS_REQUEST state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_class_request_handle (usb_core_handle_struct *pudev, 
                                       usbh_host_struct *puhost, 
                                       usbh_state_handle_struct *pustate)
{
    if (USBH_OK == class_req_state_polling_fun(pudev, puhost, pustate)) {
        scd_event_handle(pudev, puhost, pustate, HOST_EVENT_CLASS, pustate->usbh_current_state);
    }
}

/*!
    \brief      the handle function of HOST_CLASS state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_class_handle (usb_core_handle_struct *pudev, 
                               usbh_host_struct *puhost, 
                               usbh_state_handle_struct *pustate)
{
    class_state_polling_fun(pudev, puhost, pustate);
}

/*!
    \brief      the handle function of HOST_SUSPENDED state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_suspended_handle (usb_core_handle_struct *pudev, 
                                   usbh_host_struct *puhost, 
                                   usbh_state_handle_struct *pustate)
{
    /* no operation */
}

/*!
    \brief      the handle function of HOST_ERROR state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_error_handle (usb_core_handle_struct *pudev, 
                               usbh_host_struct *puhost, 
                               usbh_state_handle_struct *pustate)
{
    /* re-initilaize host for new enumeration */
    usbh_deinit (pudev, puhost,&usbh_state_core);
    puhost->usr_cb->deinit();
    puhost->class_deinit(pudev, &puhost->device);
    scd_event_handle(pudev, puhost, pustate, HOST_EVENT_IDLE, pustate->usbh_current_state);
}

/*!
    \brief      the handle function of HOST_DEV_DETACHED state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_dev_detached_handle (usb_core_handle_struct *pudev, 
                                      usbh_host_struct *puhost, 
                                      usbh_state_handle_struct *pustate)
{
    /* manage user disconnect operations*/
    puhost->usr_cb->device_disconnected();

    /* re-initilaize host for new enumeration */
    usbh_deinit(pudev, puhost,&usbh_state_core);
    puhost->usr_cb->deinit();
    puhost->class_deinit(pudev, &puhost->device);
    usbh_allchannel_dealloc(pudev);
    scd_event_handle(pudev, puhost, pustate, HOST_EVENT_IDLE, pustate->usbh_current_state);
}

/*!
    \brief      the handle function of HOST_DETECT_DEV_SPEED state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
static void host_detect_dev_speed_handle (usb_core_handle_struct *pudev, 
                                          usbh_host_struct *puhost, 
                                          usbh_state_handle_struct *pustate)
{
    /* no operation */
}

/*!
    \brief      usb connect callback function from the interrupt. 
    \param[in]  pudev: pointer to usb device
    \param[out] none
    \retval     operation status
*/
uint8_t usbh_connected (usb_core_handle_struct *pudev)
{
    pudev->host.connect_status = 1U;

    return 0U;
}

/*!
    \brief      usb disconnect callback function from the interrupt. 
    \param[in]  pudev: pointer to usb device
    \param[out] none
    \retval     operation status
*/
uint8_t usbh_disconnected (usb_core_handle_struct *pudev)
{
    pudev->host.connect_status = 0U;

    return 0U;
}

/*!
    \brief      usb sof callback function from the interrupt. 
    \param[in]  pudev: pointer to usb device
    \param[out] none
    \retval     operation status
*/
uint8_t usbh_sof (usb_core_handle_struct *pudev)
{
    /* this callback could be used to implement a scheduler process */
    return 0U;
}

/*!
    \brief      initialize the host portion of the driver.
    \param[in]  pudev: pointer to usb device
    \param[in]  core_id: usb otg core identifier(high-speed or full-speed)
    \param[out] none
    \retval     operation status
*/
uint32_t hcd_init(usb_core_handle_struct *pudev, usb_core_id_enum core_id)
{
    pudev->host.connect_status = 0U;

    pudev->host.host_channel[0].endp_mps = 8U;

    usb_core_select(pudev, core_id);

#ifndef DUAL_ROLE_MODE_ENABLED

    USB_GLOBAL_INT_DISABLE();

    usb_core_init(pudev);

    /* force host mode*/
    usb_mode_set(pudev, HOST_MODE);

    usb_hostcore_init(pudev);

    USB_GLOBAL_INT_ENABLE();

#endif

    return 0U;
}

/*!
    \brief      check if the device is connected.
    \param[in]  pudev: pointer to usb device
    \param[out] none
    \retval     device connection status. 1 -> connected and 0 -> disconnected
*/
uint32_t hcd_is_device_connected(usb_core_handle_struct *pudev)
{
    return (uint32_t)(pudev->host.connect_status);
}

/*!
    \brief      this function returns the last URBstate
    \param[in]  pudev: pointer to usb device
    \param[in]  channel_num: host channel number which is in (0..7)
    \param[out] none
    \retval     urb_state_enum
*/
urb_state_enum hcd_urb_state_get (usb_core_handle_struct *pudev, uint8_t channel_num) 
{
    return pudev->host.host_channel[channel_num].urb_state;
}

/*!
    \brief      this function returns the last URBstate
    \param[in]  pudev: pointer to usb device
    \param[in]  channel_num: host channel number which is in (0..7)
    \param[out] none
    \retval     No. of data bytes transferred
*/
uint32_t hcd_xfer_count_get (usb_core_handle_struct *pudev, uint8_t channel_num) 
{
    return pudev->host.host_channel[channel_num].xfer_count;
}

/*!
    \brief      de-initialize host
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[out] none
    \retval     host status
*/
usbh_status_enum usbh_deinit(usb_core_handle_struct *pudev, 
                             usbh_host_struct *puhost, 
                             usbh_state_handle_struct* pustate)
{
    /* software init */

    puhost->control.ep0_size = USB_MAX_EP0_SIZE;

    puhost->device.address = USBH_DEVICE_ADDRESS_DEFAULT;
    puhost->device.speed = HPRT_PRTSPD_FULL_SPEED;

    usbh_channel_free(pudev, puhost->control.hc_in_num);
    usbh_channel_free(pudev, puhost->control.hc_out_num);
    
    scd_init(pustate);
    scd_table_regist(pustate, host_handle_table, HOST_FSM_ID, HOST_HANDLE_TABLE_SIZE);
    scd_table_regist(pustate, enum_handle_table, ENUM_FSM_ID, ENUM_HANDLE_TABLE_SIZE);
    scd_table_regist(pustate, ctrl_handle_table, CTRL_FSM_ID, CTRL_HANDLE_TABLE_SIZE);
  
    scd_begin(pustate,HOST_FSM_ID);
    scd_state_move(pustate, HOST_IDLE);

    return USBH_OK;
}

/*!
    \brief      state core driver init
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
void scd_init(usbh_state_handle_struct* pustate)
{
    /* init the state core */
    pustate->usbh_current_state = 0U;
    pustate->usbh_current_state_table = NULL;
    pustate->usbh_current_state_table_size = 0U;
  
    pustate->usbh_current_state_stack_top = -1;
    pustate->stack->state = 0U;
    pustate->stack->table_size = 0U;
    pustate->stack->table = NULL;
  
    pustate->usbh_regist_state_table_num = 0U;
    pustate->usbh_regist_state_table->table = NULL;
    pustate->usbh_regist_state_table->table_size = 0U;
    pustate->usbh_regist_state_table->id = 0U;
  
    /* init the control and the enumeration polling handle flag */
    ctrl_polling_handle_flag = 0U;
    enum_polling_handle_flag = 0U;
}

/*!
    \brief      state core driver table regist
    \param[in]  pustate: pointer to usb state driver
    \param[in]  pstate_table: pointer to the table to regist
    \param[in]  table_id: the id of the table to regist
    \param[in]  current_table_size: the size of the current table to regist
    \param[out] none
    \retval     none
*/
void scd_table_regist (usbh_state_handle_struct* pustate, 
                       state_table_struct* pstate_table, 
                       uint8_t table_id, 
                       uint8_t current_table_size)
{
    usbh_state_regist_table_struct *cur_state_reg_table;

    cur_state_reg_table = &pustate->usbh_regist_state_table[pustate->usbh_regist_state_table_num];

    cur_state_reg_table->id = table_id;
    cur_state_reg_table->table = pstate_table;
    cur_state_reg_table->table_size = current_table_size;

    pustate->usbh_regist_state_table_num++;
}

/*!
    \brief      state core driver begin
    \param[in]  pustate: pointer to usb state driver
    \param[in]  table_id: the id of the table to begin
    \param[out] none
    \retval     none
*/
void scd_begin(usbh_state_handle_struct* pustate, uint8_t table_id)
{
    uint8_t i = 0U, table_num = pustate->usbh_regist_state_table_num;
    usbh_state_regist_table_struct *cur_state_reg_table;

    for (i = 0U; i < table_num; i++) {
        cur_state_reg_table = &pustate->usbh_regist_state_table[i];

        if (table_id == cur_state_reg_table->id) {
            pustate->usbh_current_state_table = cur_state_reg_table->table;
            pustate->usbh_current_state_table_size = cur_state_reg_table->table_size;
            break;
        }
    }
}

/*!
    \brief      state core driver move state
    \param[in]  pustate: pointer to usb state driver
    \param[in]  state: the state to move
    \param[out] none
    \retval     none
*/
void scd_state_move(usbh_state_handle_struct* pustate, uint8_t state)
{
    pustate->usbh_current_state = state;
}

/*!
    \brief      state core driver event handle
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[in]  event: the current event
    \param[in]  state: the current state
    \param[out] none
    \retval     host status
*/
usbh_status_enum scd_event_handle (usb_core_handle_struct *pudev, 
                                   usbh_host_struct *puhost, 
                                   usbh_state_handle_struct* pustate, 
                                   uint8_t event, 
                                   uint8_t state)
{
    uint8_t i = 0U;
    ACT_FUN event_act_fun = NULL;
    state_table_struct *backup_state_t = pustate->usbh_current_state_table;
    state_table_struct *executive_state_table = pustate->usbh_current_state_table;

    /* look up the table to find the action function */
    for (i = 0U; i < pustate->usbh_current_state_table_size; i++) {
        if (state == executive_state_table->cur_state) {
            if (event == executive_state_table->cur_event) {
                 state = executive_state_table->next_state;
                 event_act_fun = executive_state_table->event_action_fun;
                 break;
            } else {
                executive_state_table++;
            }
        } else {
            executive_state_table++;
        }
    }

    pustate->usbh_current_state_table = backup_state_t;

    /* if the action function is not NULL, execute the action function */
    if (event_act_fun) {
        if (event_act_fun == &only_state_move) {
            pustate->usbh_current_state = state;
        } else {
            return event_act_fun(pudev, puhost, pustate);
        }
    }

    return USBH_BUSY;
}

/*!
    \brief      state core driver table push
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
void scd_table_push(usbh_state_handle_struct* pustate)
{
    usbh_state_stack_struct *top_state_element;

    if (pustate->usbh_current_state_stack_top < MAX_USBH_STATE_STACK_DEEP) {
        pustate->usbh_current_state_stack_top++;

        top_state_element = &pustate->stack[pustate->usbh_current_state_stack_top];

        /* put the current state table into the state stack */
        top_state_element->state = pustate->usbh_current_state;
        top_state_element->table = pustate->usbh_current_state_table;
        top_state_element->table_size = pustate->usbh_current_state_table_size;
    }
}

/*!
    \brief      state core driver table pop
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
void scd_table_pop (usbh_state_handle_struct* pustate)
{
    usbh_state_stack_struct *top_state_element;

    top_state_element = &pustate->stack[pustate->usbh_current_state_stack_top];

    if (pustate->usbh_current_state_stack_top > -1) {
        /* get the current state table from the state stack */
        pustate->usbh_current_state = top_state_element->state;
        pustate->usbh_current_state_table = top_state_element->table;
        pustate->usbh_current_state_table_size = top_state_element->table_size;
        pustate->usbh_current_state_stack_top--;
    }
}
/*!
    \brief      the polling function of class req state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     host status
*/
static usbh_status_enum class_req_state_polling_fun (usb_core_handle_struct *pudev, usbh_host_struct *puhost, void *pustate)
{
    return class_polling_cb.class_req_polling(pudev, puhost, pustate);
}

/*!
    \brief      the polling function of class state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     host status
*/
static usbh_status_enum class_state_polling_fun (usb_core_handle_struct *pudev, usbh_host_struct *puhost, void *pustate)
{
    return class_polling_cb.class_polling(pudev, puhost, pustate);
}

/*!
    \brief      the function is only used to state move
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
usbh_status_enum only_state_move (usb_core_handle_struct *pudev, usbh_host_struct *puhost, void *pustate)
{
    return USBH_OK;
}

/*!
    \brief      the function to the up state
    \param[in]  pudev: pointer to usb device
    \param[in]  puhost: pointer to usb host
    \param[in]  pustate: pointer to usb state driver
    \param[out] none
    \retval     none
*/
usbh_status_enum goto_up_state_fun (usb_core_handle_struct *pudev, usbh_host_struct *puhost, void *pustate)
{
    scd_table_pop((usbh_state_handle_struct *)pustate);

    return USBH_OK;
}