app_usbd_cdc_acm.c

/**
 * Copyright (c) 2016 - 2017, Nordic Semiconductor ASA
 * 
 * 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, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, 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 Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 * 
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 * 
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA 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 "sdk_config.h"
#if APP_USBD_CLASS_CDC_ACM_ENABLED
#include "app_usbd_cdc_acm.h"
#include <inttypes.h>

/**
 * @defgroup app_usbd_cdc_acm_internal CDC ACM internals
 * @{
 * @ingroup app_usbd_cdc
 * @internal
 */


#define NRF_LOG_MODULE_NAME "CDC_ACM"
#if APP_USBD_CDC_ACM_LOG_ENABLED
#else //APP_USBD_CDC_ACM_LOG_ENABLED
#define NRF_LOG_LEVEL       0
#endif //APP_USBD_CDC_ACM_LOG_ENABLED
#include "nrf_log.h"


#define APP_USBD_CDC_ACM_COMM_IFACE_IDX 0    /**< CDC ACM class comm interface index. */
#define APP_USBD_CDC_ACM_DATA_IFACE_IDX 1    /**< CDC ACM class data interface index. */

#define APP_USBD_CDC_ACM_COMM_EPIN_IDX  0    /**< CDC ACM comm class endpoint IN index. */
#define APP_USBD_CDC_ACM_DATA_EPIN_IDX  0    /**< CDC ACM data class endpoint IN index. */
#define APP_USBD_CDC_ACM_DATA_EPOUT_IDX 1    /**< CDC ACM data class endpoint OUT index. */

/**
 * @brief Auxiliary function to access cdc_acm class instance data.
 *
 * @param[in] p_inst Class instance data.
 *
 * @return CDC ACM class instance.
 */
static inline app_usbd_cdc_acm_t const * cdc_acm_get(app_usbd_class_inst_t const * p_inst)
{
    ASSERT(p_inst != NULL);
    return (app_usbd_cdc_acm_t const *)p_inst;
}

/**
 * @brief Auxiliary function to access cdc_acm class context data.
 *
 * @param[in] p_cdc_acm    CDC ACM class instance data.
 *
 * @return CDC ACM class instance context.
 */
static inline app_usbd_cdc_acm_ctx_t * cdc_acm_ctx_get(app_usbd_cdc_acm_t const * p_cdc_acm)
{
    ASSERT(p_cdc_acm != NULL);
    ASSERT(p_cdc_acm->specific.p_data != NULL);
    return &p_cdc_acm->specific.p_data->ctx;
}

/**
 * @brief User event handler.
 *
 * @param[in] p_inst        Class instance.
 * @param[in] event user    Event type.
 */
static inline void user_event_handler(app_usbd_class_inst_t const * p_inst,
                                      app_usbd_cdc_acm_user_event_t event)
{
    app_usbd_cdc_acm_t const * p_cdc_acm = cdc_acm_get(p_inst);
    if (p_cdc_acm->specific.inst.user_ev_handler != NULL)
    {
        p_cdc_acm->specific.inst.user_ev_handler(p_inst, event);
    }
}

/**
 * @brief Auxiliary function to access CDC ACM COMM IN endpoint address.
 *
 * @param[in] p_inst Class instance data.
 *
 * @return IN endpoint address.
 */
static inline nrf_drv_usbd_ep_t comm_ep_in_addr_get(app_usbd_class_inst_t const * p_inst)
{
    app_usbd_class_iface_conf_t const * class_iface;
    class_iface = app_usbd_class_iface_get(p_inst, APP_USBD_CDC_ACM_COMM_IFACE_IDX);

    app_usbd_class_ep_conf_t const * ep_cfg;
    ep_cfg = app_usbd_class_iface_ep_get(class_iface, APP_USBD_CDC_ACM_COMM_EPIN_IDX);

    return app_usbd_class_ep_address_get(ep_cfg);
}

/**
 * @brief Auxiliary function to access CDC ACM DATA IN endpoint address.
 *
 * @param[in] p_inst Class instance data.
 *
 * @return IN endpoint address.
 */
static inline nrf_drv_usbd_ep_t data_ep_in_addr_get(app_usbd_class_inst_t const * p_inst)
{
    app_usbd_class_iface_conf_t const * class_iface;
    class_iface = app_usbd_class_iface_get(p_inst, APP_USBD_CDC_ACM_DATA_IFACE_IDX);

    app_usbd_class_ep_conf_t const * ep_cfg;
    ep_cfg = app_usbd_class_iface_ep_get(class_iface, APP_USBD_CDC_ACM_DATA_EPIN_IDX);

    return app_usbd_class_ep_address_get(ep_cfg);
}

/**
 * @brief Auxiliary function to access CDC ACM DATA OUT endpoint address.
 *
 * @param[in] p_inst Class instance data.
 *
 * @return OUT endpoint address.
 */
static inline nrf_drv_usbd_ep_t data_ep_out_addr_get(app_usbd_class_inst_t const * p_inst)
{
    app_usbd_class_iface_conf_t const * class_iface;
    class_iface = app_usbd_class_iface_get(p_inst, APP_USBD_CDC_ACM_DATA_IFACE_IDX);

    app_usbd_class_ep_conf_t const * ep_cfg;
    ep_cfg = app_usbd_class_iface_ep_get(class_iface, APP_USBD_CDC_ACM_DATA_EPOUT_IDX);

    return app_usbd_class_ep_address_get(ep_cfg);
}

/**
 * @brief Internal SETUP standard IN request handler.
 *
 * @param[in] p_inst        Generic class instance.
 * @param[in] p_setup_ev    Setup event.
 *
 * @return Standard error code.
 */
static ret_code_t setup_req_std_in(app_usbd_class_inst_t const * p_inst,
                                   app_usbd_setup_evt_t const *  p_setup_ev)
{
    switch (p_setup_ev->setup.bmRequest)
    {
        case APP_USBD_SETUP_STDREQ_GET_DESCRIPTOR:
        {
            size_t dsc_len = 0;

            /* Try to find descriptor in class internals*/
            void const * p_dsc = app_usbd_class_descriptor_find(p_inst,
                                                                p_setup_ev->setup.wValue.hb,
                                                                p_setup_ev->setup.wValue.lb,
                                                                &dsc_len);
            if (p_dsc != NULL)
            {
                return app_usbd_core_setup_rsp(&(p_setup_ev->setup), p_dsc, dsc_len);
            }

            break;
        }
        case APP_USBD_SETUP_STDREQ_GET_INTERFACE:
        {

            size_t tx_maxsize;
            uint8_t * p_tx_buff = app_usbd_core_setup_transfer_buff_get(&tx_maxsize);

            p_tx_buff[0] = 0;
            return app_usbd_core_setup_rsp(&p_setup_ev->setup,
                                           p_tx_buff,
                                           sizeof(uint8_t));
        }
        default:
            break;
    }

    return NRF_ERROR_NOT_SUPPORTED;
}

/**
 * @brief Internal SETUP standard OUT request handler
 *
 * @param[in] p_inst        Generic class instance
 * @param[in] p_setup_ev    Setup event
 *
 * @return Standard error code.
 */
static ret_code_t setup_req_std_out(app_usbd_class_inst_t const * p_inst,
                                    app_usbd_setup_evt_t const *  p_setup_ev)
{

    switch (p_setup_ev->setup.bmRequest)
    {
        default:
            break;
    }

    return NRF_ERROR_NOT_SUPPORTED;
}

/**
 * @brief Internal SETUP class IN request handler.
 *
 * @param[in] p_inst        Generic class instance.
 * @param[in] p_setup_ev    Setup event.
 *
 * @return Standard error code.
 */
static ret_code_t setup_req_class_in(app_usbd_class_inst_t const * p_inst,
                                     app_usbd_setup_evt_t const *  p_setup_ev)
{
    app_usbd_cdc_acm_t const * p_cdc_acm = cdc_acm_get(p_inst);
    app_usbd_cdc_acm_ctx_t *   p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    switch (p_setup_ev->setup.bmRequest)
    {
        case APP_USBD_CDC_REQ_GET_LINE_CODING:
        {
            if (p_setup_ev->setup.wLength.w != sizeof(app_usbd_cdc_line_coding_t))
            {
                return NRF_ERROR_NOT_SUPPORTED;
            }

            return app_usbd_core_setup_rsp(&p_setup_ev->setup,
                                           &p_cdc_acm_ctx->line_coding,
                                           sizeof(app_usbd_cdc_line_coding_t));
        }
        default:
            break;
    }

    return NRF_ERROR_NOT_SUPPORTED;
}

/**
 * @brief Class specific OUT request data callback.
 *
 * @param status    Endpoint status.
 * @param p_context Context of transfer (set by @ref app_usbd_core_setup_data_handler_set).
 *
 * @return Standard error code.
 */
static ret_code_t cdc_acm_req_out_data_cb(nrf_drv_usbd_ep_status_t status, void * p_context)
{
    if (status != NRF_USBD_EP_OK)
    {
        return NRF_ERROR_INTERNAL;
    }

    app_usbd_cdc_acm_t const * p_cdc_acm = p_context;
    app_usbd_cdc_acm_ctx_t *   p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    switch (p_cdc_acm_ctx->request.type)
    {
        case APP_USBD_CDC_REQ_SET_LINE_CODING:
        {
            memcpy(&p_cdc_acm_ctx->line_coding,
                   &p_cdc_acm_ctx->request.payload.line_coding,
                   sizeof(app_usbd_cdc_line_coding_t));

            NRF_LOG_INFO("REQ_SET_LINE_CODING: baudrate: %"PRIu32", databits: %u, "
                    "format: %u, parity: %u\r\n",
                    uint32_decode(p_cdc_acm_ctx->line_coding.dwDTERate),
                    p_cdc_acm_ctx->line_coding.bDataBits,
                    p_cdc_acm_ctx->line_coding.bCharFormat,
                    p_cdc_acm_ctx->line_coding.bParityType);
            break;
        }
        default:
            return NRF_ERROR_NOT_SUPPORTED;
    }

    return NRF_SUCCESS;
}


/**
 * @brief Class specific request data stage setup.
 *
 * @param[in] p_inst        Generic class instance.
 * @param[in] p_setup_ev    Setup event.
 *
 * @return Standard error code.
 */
static ret_code_t cdc_acm_req_out_datastage(app_usbd_class_inst_t const * p_inst,
                                            app_usbd_setup_evt_t const *  p_setup_ev)
{
    app_usbd_cdc_acm_t const * p_cdc_acm = cdc_acm_get(p_inst);
    app_usbd_cdc_acm_ctx_t *   p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    p_cdc_acm_ctx->request.type = p_setup_ev->setup.bmRequest;
    p_cdc_acm_ctx->request.len = p_setup_ev->setup.wLength.w;

    /*Request setup data*/
    NRF_DRV_USBD_TRANSFER_OUT(transfer,
                              &p_cdc_acm_ctx->request.payload,
                              p_cdc_acm_ctx->request.len);
    ret_code_t ret;
    CRITICAL_REGION_ENTER();
    ret = app_usbd_core_setup_data_transfer(NRF_DRV_USBD_EPOUT0, &transfer);
    if (ret == NRF_SUCCESS)
    {
        const app_usbd_core_setup_data_handler_desc_t desc = {
                .handler = cdc_acm_req_out_data_cb,
                .p_context = (void*)p_cdc_acm
        };

        ret = app_usbd_core_setup_data_handler_set(NRF_DRV_USBD_EPOUT0, &desc);
    }
    CRITICAL_REGION_EXIT();

    return ret;
}

/**
 * @brief Internal SETUP class OUT request handler.
 *
 * @param[in] p_inst        Generic class instance.
 * @param[in] p_setup_ev    Setup event.
 *
 * @return Standard error code.
 */
static ret_code_t setup_req_class_out(app_usbd_class_inst_t const * p_inst,
                                      app_usbd_setup_evt_t const *  p_setup_ev)
{
    app_usbd_cdc_acm_t const * p_cdc_acm = cdc_acm_get(p_inst);
    app_usbd_cdc_acm_ctx_t *   p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    switch (p_setup_ev->setup.bmRequest)
    {
        case APP_USBD_CDC_REQ_SET_LINE_CODING:
        {
            if (p_setup_ev->setup.wLength.w != sizeof(app_usbd_cdc_line_coding_t))
            {
                return NRF_ERROR_NOT_SUPPORTED;
            }

            return cdc_acm_req_out_datastage(p_inst, p_setup_ev);
        }
        case APP_USBD_CDC_REQ_SET_CONTROL_LINE_STATE:
        {
            if (p_setup_ev->setup.wLength.w != 0)
            {
                return NRF_ERROR_NOT_SUPPORTED;
            }

            NRF_LOG_INFO("REQ_SET_CONTROL_LINE_STATE: 0x%x\r\n", p_setup_ev->setup.wValue.w);

            bool old_dtr = (p_cdc_acm_ctx->line_state & APP_USBD_CDC_ACM_LINE_STATE_DTR) ?
                            true : false;
            p_cdc_acm_ctx->line_state = p_setup_ev->setup.wValue.w;

            bool new_dtr = (p_cdc_acm_ctx->line_state & APP_USBD_CDC_ACM_LINE_STATE_DTR) ?
                            true : false;

            if (old_dtr == new_dtr)
            {
                return NRF_SUCCESS;
            }

            const app_usbd_cdc_acm_user_event_t ev = new_dtr ?
                  APP_USBD_CDC_ACM_USER_EVT_PORT_OPEN : APP_USBD_CDC_ACM_USER_EVT_PORT_CLOSE;

            user_event_handler(p_inst, ev);

            if (!new_dtr)
            {
                /*Abort DATA endpoints on port close */
                nrf_drv_usbd_ep_t ep;
                ep = data_ep_in_addr_get(p_inst);
                usbd_drv_ep_abort(ep);
                ep = data_ep_out_addr_get(p_inst);
                usbd_drv_ep_abort(ep);
            }

            return NRF_SUCCESS;
        }
        default:
            break;
    }

    return NRF_ERROR_NOT_SUPPORTED;
}

/**
 * @brief Control endpoint handler.
 *
 * @param[in] p_inst        Generic class instance.
 * @param[in] p_setup_ev    Setup event.
 *
 * @return Standard error code.
 */
static ret_code_t setup_event_handler(app_usbd_class_inst_t const * p_inst,
                                      app_usbd_setup_evt_t const *  p_setup_ev)
{
    ASSERT(p_inst != NULL);
    ASSERT(p_setup_ev != NULL);

    if (app_usbd_setup_req_dir(p_setup_ev->setup.bmRequestType) == APP_USBD_SETUP_REQDIR_IN)
    {
        switch (app_usbd_setup_req_typ(p_setup_ev->setup.bmRequestType))
        {
            case APP_USBD_SETUP_REQTYPE_STD:
                return setup_req_std_in(p_inst, p_setup_ev);
            case APP_USBD_SETUP_REQTYPE_CLASS:
                return setup_req_class_in(p_inst, p_setup_ev);
            default:
                break;
        }
    }
    else /*APP_USBD_SETUP_REQDIR_OUT*/
    {
        switch (app_usbd_setup_req_typ(p_setup_ev->setup.bmRequestType))
        {
            case APP_USBD_SETUP_REQTYPE_STD:
                return setup_req_std_out(p_inst, p_setup_ev);
            case APP_USBD_SETUP_REQTYPE_CLASS:
                return setup_req_class_out(p_inst, p_setup_ev);
            default:
                break;
        }
    }

    return NRF_ERROR_NOT_SUPPORTED;
}

/**
 * @brief Class specific endpoint transfer handler.
 *
 * @param[in] p_inst        Generic class instance.
 * @param[in] p_setup_ev    Setup event.
 *
 * @return Standard error code.
 */
static ret_code_t cdc_acm_endpoint_ev(app_usbd_class_inst_t const *  p_inst,
                                      app_usbd_complex_evt_t const * p_event)
{
    if (comm_ep_in_addr_get(p_inst) == p_event->drv_evt.data.eptransfer.ep)
    {
        NRF_LOG_INFO("EPIN_COMM: notify\r\n");
        return NRF_SUCCESS;
    }

    if (NRF_USBD_EPIN_CHECK(p_event->drv_evt.data.eptransfer.ep))
    {
        switch (p_event->drv_evt.data.eptransfer.status)
        {
            case NRF_USBD_EP_OK:
                NRF_LOG_INFO("EPIN_DATA: %02x done\r\n", p_event->drv_evt.data.eptransfer.ep);
                user_event_handler(p_inst, APP_USBD_CDC_ACM_USER_EVT_TX_DONE);
                return NRF_SUCCESS;
            case NRF_USBD_EP_ABORTED:
                return NRF_SUCCESS;
            default:
                return NRF_ERROR_INTERNAL;
        }
    }

    if (NRF_USBD_EPOUT_CHECK(p_event->drv_evt.data.eptransfer.ep))
    {
        switch (p_event->drv_evt.data.eptransfer.status)
        {
            case NRF_USBD_EP_OK:
                NRF_LOG_INFO("EPOUT_DATA: %02x done\r\n", p_event->drv_evt.data.eptransfer.ep);
                user_event_handler(p_inst, APP_USBD_CDC_ACM_USER_EVT_RX_DONE);
                return NRF_SUCCESS;
            case NRF_USBD_EP_WAITING:
            case NRF_USBD_EP_ABORTED:
                return NRF_SUCCESS;
            default:
                return NRF_ERROR_INTERNAL;
        }
    }

    return NRF_ERROR_NOT_SUPPORTED;
}


/**
 * @brief @ref app_usbd_class_methods_t::event_handler
 */
static ret_code_t cdc_acm_event_handler(app_usbd_class_inst_t const *  p_inst,
                                        app_usbd_complex_evt_t const * p_event)
{
    ASSERT(p_inst != NULL);
    ASSERT(p_event != NULL);

    ret_code_t ret = NRF_SUCCESS;
    switch (p_event->app_evt.type)
    {
        case APP_USBD_EVT_DRV_SOF:
            break;
        case APP_USBD_EVT_DRV_RESET:
            break;
        case APP_USBD_EVT_DRV_SETUP:
            ret  = setup_event_handler(p_inst, (app_usbd_setup_evt_t const *)p_event);
            break;
        case APP_USBD_EVT_DRV_EPTRANSFER:
            ret = cdc_acm_endpoint_ev(p_inst, p_event);
            break;
        case APP_USBD_EVT_DRV_SUSPEND:
            break;
        case APP_USBD_EVT_DRV_RESUME:
            break;
        case APP_USBD_EVT_INST_APPEND:
        {
            ret = app_usbd_class_sof_register(p_inst);
            break;
        }
        case APP_USBD_EVT_INST_REMOVE:
        {
            ret = app_usbd_class_sof_unregister(p_inst);
            break;
        }
        case APP_USBD_EVT_START:
            break;
        case APP_USBD_EVT_STOP:
            break;
        default:
            ret = NRF_ERROR_NOT_SUPPORTED;
            break;
    }

    return ret;
}

/**
 * @brief @ref app_usbd_class_methods_t::get_descriptors
 */
static const void * cdc_acm_get_descriptors(app_usbd_class_inst_t const * p_inst,
                                            size_t *                      p_size)
{
    ASSERT(p_size != NULL);
    app_usbd_cdc_acm_t const * p_cdc_acm = cdc_acm_get(p_inst);

    *p_size = p_cdc_acm->specific.inst.raw_desc_size;
    return p_cdc_acm->specific.inst.p_raw_desc;
}

/**
 * @brief Public cdc_acm class interface
 *
 */
const app_usbd_class_methods_t app_usbd_cdc_acm_class_methods = {
        .event_handler = cdc_acm_event_handler,
        .get_descriptors = cdc_acm_get_descriptors,
};


ret_code_t app_usbd_cdc_acm_write(app_usbd_cdc_acm_t const * p_cdc_acm,
                                  const void *               p_buf,
                                  size_t                     length)
{
    app_usbd_class_inst_t const * p_inst = app_usbd_cdc_acm_class_inst_get(p_cdc_acm);
    app_usbd_cdc_acm_ctx_t * p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    bool dtr_state = (p_cdc_acm_ctx->line_state & APP_USBD_CDC_ACM_LINE_STATE_DTR) ?
                      true : false;
    if (!dtr_state)
    {
        /*Port is not opened*/
        return NRF_ERROR_INVALID_STATE;
    }

    nrf_drv_usbd_ep_t ep = data_ep_in_addr_get(p_inst);
    NRF_DRV_USBD_TRANSFER_IN(transfer, p_buf, length);
    return app_usbd_core_ep_transfer(ep, &transfer);
}

size_t app_usbd_cdc_acm_rx_size(app_usbd_cdc_acm_t const * p_cdc_acm)
{
    app_usbd_class_inst_t const * p_inst = app_usbd_cdc_acm_class_inst_get(p_cdc_acm);
    nrf_drv_usbd_ep_t ep = data_ep_out_addr_get(p_inst);

    size_t size;
    ret_code_t ret = nrf_drv_usbd_ep_status_get(ep, &size);
    if (ret != NRF_SUCCESS)
    {
        return 0;
    }

    return size;
}

ret_code_t app_usbd_cdc_acm_read(app_usbd_cdc_acm_t const * p_cdc_acm,
                                 void *                     p_buf,
                                 size_t                     length)
{
    ASSERT((length % NRF_DRV_USBD_EPSIZE) == 0);
    app_usbd_class_inst_t const * p_inst = app_usbd_cdc_acm_class_inst_get(p_cdc_acm);
    app_usbd_cdc_acm_ctx_t * p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    bool dtr_state = (p_cdc_acm_ctx->line_state & APP_USBD_CDC_ACM_LINE_STATE_DTR) ?
                      true : false;
    if (!dtr_state)
    {
        /*Port is not opened*/
        return NRF_ERROR_INVALID_STATE;
    }

    nrf_drv_usbd_ep_t ep = data_ep_out_addr_get(p_inst);
    NRF_DRV_USBD_TRANSFER_OUT(transfer, p_buf, length);
    return app_usbd_core_ep_transfer(ep, &transfer);
}

static ret_code_t cdc_acm_serial_state_notify(app_usbd_cdc_acm_t const * p_cdc_acm)
{
    app_usbd_class_inst_t const * p_inst = app_usbd_cdc_acm_class_inst_get(p_cdc_acm);
    app_usbd_cdc_acm_ctx_t *      p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    nrf_drv_usbd_ep_t ep = comm_ep_in_addr_get(p_inst);

    NRF_DRV_USBD_TRANSFER_OUT(transfer,
                              &p_cdc_acm_ctx->request.payload,
                              sizeof(app_usbd_cdc_acm_notify_t));
    return app_usbd_core_ep_transfer(ep, &transfer);
}

ret_code_t app_usbd_cdc_acm_serial_state_notify(app_usbd_cdc_acm_t const *      p_cdc_acm,
                                                app_usbd_cdc_acm_serial_state_t serial_state,
                                                bool                            value)
{
    app_usbd_cdc_acm_ctx_t * p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    ret_code_t ret;
    CRITICAL_REGION_ENTER();
    ret = NRF_SUCCESS;
    switch (serial_state)
    {
        case APP_USBD_CDC_ACM_SERIAL_STATE_DCD:
        case APP_USBD_CDC_ACM_SERIAL_STATE_DSR:
        case APP_USBD_CDC_ACM_SERIAL_STATE_BREAK:
        case APP_USBD_CDC_ACM_SERIAL_STATE_RING:
        case APP_USBD_CDC_ACM_SERIAL_STATE_FRAMING:
        case APP_USBD_CDC_ACM_SERIAL_STATE_PARITY:
        case APP_USBD_CDC_ACM_SERIAL_STATE_OVERRUN:

            if (value)
            {
                p_cdc_acm_ctx->serial_state |= serial_state;
            }
            else
            {
                p_cdc_acm_ctx->serial_state &= ~serial_state;
            }

            break;
        default:
            ret = NRF_ERROR_NOT_SUPPORTED;
            break;
    }

    if (ret == NRF_SUCCESS)
    {
        app_usbd_cdc_acm_notify_t * notify = &p_cdc_acm_ctx->request.payload.notify;
        notify->cdc_notify.bmRequestType = app_usbd_setup_req_val(APP_USBD_SETUP_REQREC_INTERFACE,
                                                                  APP_USBD_SETUP_REQTYPE_CLASS,
                                                                  APP_USBD_SETUP_REQDIR_IN);
        notify->cdc_notify.bmRequest = APP_USBD_CDC_NOTIF_SERIAL_STATE;
        notify->cdc_notify.wValue = 0;
        notify->cdc_notify.wIndex = 0;
        notify->cdc_notify.wLength = sizeof(notify->serial_state);

        notify->serial_state = p_cdc_acm_ctx->serial_state;

        ret = cdc_acm_serial_state_notify(p_cdc_acm);
    }
    CRITICAL_REGION_EXIT();

    return ret;
}

ret_code_t app_usbd_cdc_acm_line_state_get(app_usbd_cdc_acm_t const *    p_cdc_acm,
                                           app_usbd_cdc_acm_line_state_t line_state,
                                           uint32_t *                    value)
{
    app_usbd_cdc_acm_ctx_t * p_cdc_acm_ctx = cdc_acm_ctx_get(p_cdc_acm);

    ret_code_t ret;
    CRITICAL_REGION_ENTER();
    ret = NRF_SUCCESS;
    switch (line_state)
    {
        case APP_USBD_CDC_ACM_LINE_STATE_DTR:
        case APP_USBD_CDC_ACM_LINE_STATE_RTS:
            *value = (p_cdc_acm_ctx->line_state & line_state) != 0;
            break;
        default:
            ret = NRF_ERROR_NOT_SUPPORTED;
            break;
    }
    CRITICAL_REGION_EXIT();

    return ret;
}

#endif /* APP_USBD_CLASS_CDC_ACM_ENABLED */

/** @} */