text: /**
    ******************************************************************************
    * @file    usbd_audio.c
    * @author  MCD Application Team
    * @brief   This file provides the Audio core functions.
    *
    * @verbatim
    *
    *          ===================================================================
    *                                AUDIO Class  Description
    *          ===================================================================
   *           This driver manages the Audio Class 1.0 following the "USB Device Class Definition for
    *           Audio Devices V1.0 Mar 18, 98".
    *           This driver implements the following aspects of the specification:
    *             - Device descriptor management
    *             - Configuration descriptor management
    *             - Standard AC Interface Descriptor management
    *             - 1 Audio Streaming Interface (with single channel, PCM, Stereo mode)
    *             - 1 Audio Streaming Endpoint
    *             - 1 Audio Terminal Input (1 channel)
    *             - Audio Class-Specific AC Interfaces
    *             - Audio Class-Specific AS Interfaces
    *             - AudioControl Requests: only SET_CUR and GET_CUR requests are supported (for Mute)
    *             - Audio Feature Unit (limited to Mute control)
    *             - Audio Synchronization type: Asynchronous
    *             - Single fixed audio sampling rate (configurable in usbd_conf.h file)
    *          The current audio class version supports the following audio features:
    *             - Pulse Coded Modulation (PCM) format
    *             - sampling rate: 48KHz.
    *             - Bit resolution: 16
    *             - Number of channels: 2
    *             - No volume control
    *             - Mute/Unmute capability
    *             - Asynchronous Endpoints
    *
    * @note     In HS mode and when the DMA is used, all variables and data structures
    *           dealing with the DMA during the transaction process should be 32-bit aligned.
    *
    *
    *  @endverbatim
    *
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; Copyright (c) 2015 STMicroelectronics.
    * All rights reserved.</center></h2>
    *
    * This software component is licensed by ST under Ultimate Liberty license
    * SLA0044, the "License"; You may not use this file except in compliance with
    * the License. You may obtain a copy of the License at:
    *                      http://www.st.com/SLA0044
    *
    ******************************************************************************
    */
  
  /* BSPDependencies
  - "stm32xxxxx_{eval}{discovery}.c"
  - "stm32xxxxx_{eval}{discovery}_io.c"
  - "stm32xxxxx_{eval}{discovery}_audio.c"
  EndBSPDependencies */
  
  /* Includes ------------------------------------------------------------------*/
  #include "usbd_audio.h"
  #include "usbd_ctlreq.h"
  
  
  /** @addtogroup STM32_USB_DEVICE_LIBRARY
    * @{
    */
  
  
  /** @defgroup USBD_AUDIO
    * @brief usbd core module
    * @{
    */
  
  /** @defgroup USBD_AUDIO_Private_TypesDefinitions
    * @{
    */
  /**
    * @}
    */
  
  
  /** @defgroup USBD_AUDIO_Private_Defines
    * @{
    */
  /**
    * @}
    */
  
  
  /** @defgroup USBD_AUDIO_Private_Macros
    * @{
    */
  #define AUDIO_SAMPLE_FREQ(frq)      (uint8_t)(frq), (uint8_t)((frq >> 8)), (uint8_t)((frq >> 16))
  
  #define AUDIO_PACKET_SZE(frq)          (uint8_t)(((frq * 2U * 2U)/1000U) & 0xFFU), \
                                         (uint8_t)((((frq * 2U * 2U)/1000U) >> 8) & 0xFFU)
  
  /**
    * @}
    */
  
  
  
  
  /** @defgroup USBD_AUDIO_Private_FunctionPrototypes
    * @{
    */
  
  
  static uint8_t  USBD_AUDIO_Init(USBD_HandleTypeDef *pdev,
                                  uint8_t cfgidx);
  
  static uint8_t  USBD_AUDIO_DeInit(USBD_HandleTypeDef *pdev,
                                    uint8_t cfgidx);
  
  static uint8_t  USBD_AUDIO_Setup(USBD_HandleTypeDef *pdev,
                                   USBD_SetupReqTypedef *req);
  
  static uint8_t  *USBD_AUDIO_GetCfgDesc(uint16_t *length);
  
  static uint8_t  *USBD_AUDIO_GetDeviceQualifierDesc(uint16_t *length);
  
  static uint8_t  USBD_AUDIO_DataIn(USBD_HandleTypeDef *pdev, uint8_t epnum);
  
  static uint8_t  USBD_AUDIO_DataOut(USBD_HandleTypeDef *pdev, uint8_t epnum);
  
  static uint8_t  USBD_AUDIO_EP0_RxReady(USBD_HandleTypeDef *pdev);
  
  static uint8_t  USBD_AUDIO_EP0_TxReady(USBD_HandleTypeDef *pdev);
  
  static uint8_t  USBD_AUDIO_SOF(USBD_HandleTypeDef *pdev);
  
  static uint8_t  USBD_AUDIO_IsoINIncomplete(USBD_HandleTypeDef *pdev, uint8_t epnum);
  
  static uint8_t  USBD_AUDIO_IsoOutIncomplete(USBD_HandleTypeDef *pdev, uint8_t epnum);
  
  static void AUDIO_REQ_GetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req);
  
  static void AUDIO_REQ_SetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req);
  
  /**
    * @}
    */
  
  /** @defgroup USBD_AUDIO_Private_Variables
    * @{
    */
  
  USBD_ClassTypeDef  USBD_AUDIO = {
    USBD_AUDIO_Init,
    USBD_AUDIO_DeInit,
    USBD_AUDIO_Setup,
    USBD_AUDIO_EP0_TxReady,
    USBD_AUDIO_EP0_RxReady,
    USBD_AUDIO_DataIn,
    USBD_AUDIO_DataOut,
    USBD_AUDIO_SOF,
    USBD_AUDIO_IsoINIncomplete,
    USBD_AUDIO_IsoOutIncomplete,
    USBD_AUDIO_GetCfgDesc,
    USBD_AUDIO_GetCfgDesc,
    USBD_AUDIO_GetCfgDesc,
    USBD_AUDIO_GetDeviceQualifierDesc,
  };
  
  /* USB AUDIO device Configuration Descriptor */
  __ALIGN_BEGIN static uint8_t USBD_AUDIO_CfgDesc[USB_AUDIO_CONFIG_DESC_SIZ] __ALIGN_END = {
    /* Configuration 1 */
    0x09,                                 /* bLength */
    USB_DESC_TYPE_CONFIGURATION,          /* bDescriptorType */
    LOBYTE(USB_AUDIO_CONFIG_DESC_SIZ),    /* wTotalLength  109 bytes*/
    HIBYTE(USB_AUDIO_CONFIG_DESC_SIZ),
    0x02,                                 /* bNumInterfaces */
    0x01,                                 /* bConfigurationValue */
    0x00,                                 /* iConfiguration */
    0xC0,                                 /* bmAttributes  BUS Powred*/
    0x32,                                 /* bMaxPower = 100 mA*/
    /* 09 byte*/
  
    /* USB Speaker Standard interface descriptor */
    AUDIO_INTERFACE_DESC_SIZE,            /* bLength */
    USB_DESC_TYPE_INTERFACE,              /* bDescriptorType */
    0x00,                                 /* bInterfaceNumber */
    0x00,                                 /* bAlternateSetting */
    0x00,                                 /* bNumEndpoints */
    USB_DEVICE_CLASS_AUDIO,               /* bInterfaceClass */
    AUDIO_SUBCLASS_AUDIOCONTROL,          /* bInterfaceSubClass */
    AUDIO_PROTOCOL_UNDEFINED,             /* bInterfaceProtocol */
    0x00,                                 /* iInterface */
    /* 09 byte*/
  
    /* USB Speaker Class-specific AC Interface Descriptor */
    AUDIO_INTERFACE_DESC_SIZE,            /* bLength */
    AUDIO_INTERFACE_DESCRIPTOR_TYPE,      /* bDescriptorType */
    AUDIO_CONTROL_HEADER,                 /* bDescriptorSubtype */
    0x00,          /* 1.00 */             /* bcdADC */
    0x01,
    0x27,                                 /* wTotalLength = 39*/
    0x00,
    0x01,                                 /* bInCollection */
    0x01,                                 /* baInterfaceNr */
    /* 09 byte*/
  
    /* USB Speaker Input Terminal Descriptor */
    AUDIO_INPUT_TERMINAL_DESC_SIZE,       /* bLength */
    AUDIO_INTERFACE_DESCRIPTOR_TYPE,      /* bDescriptorType */
    AUDIO_CONTROL_INPUT_TERMINAL,         /* bDescriptorSubtype */
    0x01,                                 /* bTerminalID */
    0x01,                                 /* wTerminalType AUDIO_TERMINAL_USB_STREAMING   0x0101 */
    0x01,
    0x00,                                 /* bAssocTerminal */
    0x01,                                 /* bNrChannels */
    0x00,                                 /* wChannelConfig 0x0000  Mono */
    0x00,
    0x00,                                 /* iChannelNames */
    0x00,                                 /* iTerminal */
    /* 12 byte*/
  
    /* USB Speaker Audio Feature Unit Descriptor */
    0x09,                                 /* bLength */
    AUDIO_INTERFACE_DESCRIPTOR_TYPE,      /* bDescriptorType */
    AUDIO_CONTROL_FEATURE_UNIT,           /* bDescriptorSubtype */
    AUDIO_OUT_STREAMING_CTRL,             /* bUnitID */
    0x01,                                 /* bSourceID */
    0x01,                                 /* bControlSize */
    AUDIO_CONTROL_MUTE,                   /* bmaControls(0) */
    0,                                    /* bmaControls(1) */
    0x00,                                 /* iTerminal */
    /* 09 byte*/
  
    /*USB Speaker Output Terminal Descriptor */
    0x09,      /* bLength */
    AUDIO_INTERFACE_DESCRIPTOR_TYPE,      /* bDescriptorType */
    AUDIO_CONTROL_OUTPUT_TERMINAL,        /* bDescriptorSubtype */
    0x03,                                 /* bTerminalID */
    0x01,                                 /* wTerminalType  0x0301*/
    0x03,
    0x00,                                 /* bAssocTerminal */
    0x02,                                 /* bSourceID */
    0x00,                                 /* iTerminal */
    /* 09 byte*/
  
    /* USB Speaker Standard AS Interface Descriptor - Audio Streaming Zero Bandwith */
    /* Interface 1, Alternate Setting 0                                             */
    AUDIO_INTERFACE_DESC_SIZE,  /* bLength */
    USB_DESC_TYPE_INTERFACE,        /* bDescriptorType */
    0x01,                                 /* bInterfaceNumber */
    0x00,                                 /* bAlternateSetting */
    0x00,                                 /* bNumEndpoints */
    USB_DEVICE_CLASS_AUDIO,               /* bInterfaceClass */
    AUDIO_SUBCLASS_AUDIOSTREAMING,        /* bInterfaceSubClass */
    AUDIO_PROTOCOL_UNDEFINED,             /* bInterfaceProtocol */
    0x00,                                 /* iInterface */
    /* 09 byte*/
  
    /* USB Speaker Standard AS Interface Descriptor - Audio Streaming Operational */
    /* Interface 1, Alternate Setting 1                                           */
    AUDIO_INTERFACE_DESC_SIZE,  /* bLength */
    USB_DESC_TYPE_INTERFACE,        /* bDescriptorType */
    0x01,                                 /* bInterfaceNumber */
    0x01,                                 /* bAlternateSetting */
    0x01,                                 /* bNumEndpoints */
    USB_DEVICE_CLASS_AUDIO,               /* bInterfaceClass */
    AUDIO_SUBCLASS_AUDIOSTREAMING,        /* bInterfaceSubClass */
    AUDIO_PROTOCOL_UNDEFINED,             /* bInterfaceProtocol */
    0x00,                                 /* iInterface */
    /* 09 byte*/
  
    /* USB Speaker Audio Streaming Interface Descriptor */
    AUDIO_STREAMING_INTERFACE_DESC_SIZE,  /* bLength */
    AUDIO_INTERFACE_DESCRIPTOR_TYPE,      /* bDescriptorType */
    AUDIO_STREAMING_GENERAL,              /* bDescriptorSubtype */
    0x01,                                 /* bTerminalLink */
    0x01,                                 /* bDelay */
    0x01,                                 /* wFormatTag AUDIO_FORMAT_PCM  0x0001*/
    0x00,
    /* 07 byte*/
  
    /* USB Speaker Audio Type III Format Interface Descriptor */
    0x0B,                                 /* bLength */
    AUDIO_INTERFACE_DESCRIPTOR_TYPE,      /* bDescriptorType */
    AUDIO_STREAMING_FORMAT_TYPE,          /* bDescriptorSubtype */
    AUDIO_FORMAT_TYPE_I,                /* bFormatType */
    0x02,                                 /* bNrChannels */
    0x02,                                 /* bSubFrameSize :  2 Bytes per frame (16bits) */
    16,                                   /* bBitResolution (16-bits per sample) */
    0x01,                                 /* bSamFreqType only one frequency supported */
    AUDIO_SAMPLE_FREQ(USBD_AUDIO_FREQ),         /* Audio sampling frequency coded on 3 bytes */
    /* 11 byte*/
  
    /* Endpoint 1 - Standard Descriptor */
    AUDIO_STANDARD_ENDPOINT_DESC_SIZE,    /* bLength */
    USB_DESC_TYPE_ENDPOINT,               /* bDescriptorType */
    AUDIO_OUT_EP,                         /* bEndpointAddress 1 out endpoint*/
    USBD_EP_TYPE_ISOC,                    /* bmAttributes */
    AUDIO_PACKET_SZE(USBD_AUDIO_FREQ),    /* wMaxPacketSize in Bytes (Freq(Samples)*2(Stereo)*2(HalfWord)) */
    0x01,                                 /* bInterval */
    0x00,                                 /* bRefresh */
    0x00,                                 /* bSynchAddress */
    /* 09 byte*/
  
    /* Endpoint - Audio Streaming Descriptor*/
    AUDIO_STREAMING_ENDPOINT_DESC_SIZE,   /* bLength */
    AUDIO_ENDPOINT_DESCRIPTOR_TYPE,       /* bDescriptorType */
    AUDIO_ENDPOINT_GENERAL,               /* bDescriptor */
    0x00,                                 /* bmAttributes */
    0x00,                                 /* bLockDelayUnits */
    0x00,                                 /* wLockDelay */
    0x00,
    /* 07 byte*/
  } ;
  
  /* USB Standard Device Descriptor */
  __ALIGN_BEGIN static uint8_t USBD_AUDIO_DeviceQualifierDesc[USB_LEN_DEV_QUALIFIER_DESC] __ALIGN_END = {
    USB_LEN_DEV_QUALIFIER_DESC,
    USB_DESC_TYPE_DEVICE_QUALIFIER,
    0x00,
    0x02,
    0x00,
    0x00,
    0x00,
    0x40,
    0x01,
    0x00,
  };
  
  /**
    * @}
    */
  
  /** @defgroup USBD_AUDIO_Private_Functions
    * @{
    */
  
  /**
    * @brief  USBD_AUDIO_Init
    *         Initialize the AUDIO interface
    * @param  pdev: device instance
    * @param  cfgidx: Configuration index
    * @retval status
    */
  static uint8_t  USBD_AUDIO_Init(USBD_HandleTypeDef *pdev, uint8_t cfgidx)
  {
    USBD_AUDIO_HandleTypeDef   *haudio;
  
    /* Open EP OUT */
    USBD_LL_OpenEP(pdev, AUDIO_OUT_EP, USBD_EP_TYPE_ISOC, AUDIO_OUT_PACKET);
    pdev->ep_out[AUDIO_OUT_EP & 0xFU].is_used = 1U;
  
    /* Allocate Audio structure */
    pdev->pClassData = USBD_malloc(sizeof(USBD_AUDIO_HandleTypeDef));
  
    if (pdev->pClassData == NULL) {
      return USBD_FAIL;
    } else {
      haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
      haudio->alt_setting = 0U;
      haudio->offset = AUDIO_OFFSET_UNKNOWN;
      haudio->wr_ptr = 0U;
      haudio->rd_ptr = 0U;
      haudio->rd_enable = 0U;
  
      /* Initialize the Audio output Hardware layer */
      if (((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->Init(USBD_AUDIO_FREQ,
                                                           AUDIO_DEFAULT_VOLUME,
                                                           0U) != 0) {
        return USBD_FAIL;
      }
  
      /* Prepare Out endpoint to receive 1st packet */
      USBD_LL_PrepareReceive(pdev, AUDIO_OUT_EP, haudio->buffer,
                             AUDIO_OUT_PACKET);
    }
    return USBD_OK;
  }
  
  /**
    * @brief  USBD_AUDIO_Init
    *         DeInitialize the AUDIO layer
    * @param  pdev: device instance
    * @param  cfgidx: Configuration index
    * @retval status
    */
  static uint8_t  USBD_AUDIO_DeInit(USBD_HandleTypeDef *pdev,
                                    uint8_t cfgidx)
  {
  
    /* Open EP OUT */
    USBD_LL_CloseEP(pdev, AUDIO_OUT_EP);
    pdev->ep_out[AUDIO_OUT_EP & 0xFU].is_used = 0U;
  
    /* DeInit  physical Interface components */
    if (pdev->pClassData != NULL) {
      ((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->DeInit(0U);
      USBD_free(pdev->pClassData);
      pdev->pClassData = NULL;
    }
  
    return USBD_OK;
  }
  
  /**
    * @brief  USBD_AUDIO_Setup
    *         Handle the AUDIO specific requests
    * @param  pdev: instance
    * @param  req: usb requests
    * @retval status
    */
  static uint8_t  USBD_AUDIO_Setup(USBD_HandleTypeDef *pdev,
                                   USBD_SetupReqTypedef *req)
  {
    USBD_AUDIO_HandleTypeDef *haudio;
    uint16_t len;
    uint8_t *pbuf;
    uint16_t status_info = 0U;
    uint8_t ret = USBD_OK;
  
    haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
  
    switch (req->bmRequest & USB_REQ_TYPE_MASK) {
      case USB_REQ_TYPE_CLASS :
        switch (req->bRequest) {
          case AUDIO_REQ_GET_CUR:
            AUDIO_REQ_GetCurrent(pdev, req);
            break;
  
          case AUDIO_REQ_SET_CUR:
            AUDIO_REQ_SetCurrent(pdev, req);
            break;
  
          default:
            USBD_CtlError(pdev, req);
            ret = USBD_FAIL;
            break;
        }
        break;
  
      case USB_REQ_TYPE_STANDARD:
        switch (req->bRequest) {
          case USB_REQ_GET_STATUS:
            if (pdev->dev_state == USBD_STATE_CONFIGURED) {
              USBD_CtlSendData(pdev, (uint8_t *)(void *)&status_info, 2U);
            } else {
              USBD_CtlError(pdev, req);
              ret = USBD_FAIL;
            }
            break;
  
          case USB_REQ_GET_DESCRIPTOR:
            if ((req->wValue >> 8) == AUDIO_DESCRIPTOR_TYPE) {
              pbuf = USBD_AUDIO_CfgDesc + 18;
              len = MIN(USB_AUDIO_DESC_SIZ, req->wLength);
  
              USBD_CtlSendData(pdev, pbuf, len);
            }
            break;
  
          case USB_REQ_GET_INTERFACE :
            if (pdev->dev_state == USBD_STATE_CONFIGURED) {
              USBD_CtlSendData(pdev, (uint8_t *)(void *)&haudio->alt_setting, 1U);
            } else {
              USBD_CtlError(pdev, req);
              ret = USBD_FAIL;
            }
            break;
  
          case USB_REQ_SET_INTERFACE :
            if (pdev->dev_state == USBD_STATE_CONFIGURED) {
              if ((uint8_t)(req->wValue) <= USBD_MAX_NUM_INTERFACES) {
                haudio->alt_setting = (uint8_t)(req->wValue);
              } else {
                /* Call the error management function (command will be nacked */
                USBD_CtlError(pdev, req);
                ret = USBD_FAIL;
              }
            } else {
              USBD_CtlError(pdev, req);
              ret = USBD_FAIL;
            }
            break;
  
          default:
            USBD_CtlError(pdev, req);
            ret = USBD_FAIL;
            break;
        }
        break;
      default:
        USBD_CtlError(pdev, req);
        ret = USBD_FAIL;
        break;
    }
  
    return ret;
  }
  
  
  /**
    * @brief  USBD_AUDIO_GetCfgDesc
    *         return configuration descriptor
    * @param  speed : current device speed
    * @param  length : pointer data length
    * @retval pointer to descriptor buffer
    */
  static uint8_t  *USBD_AUDIO_GetCfgDesc(uint16_t *length)
  {
    *length = sizeof(USBD_AUDIO_CfgDesc);
    return USBD_AUDIO_CfgDesc;
  }
  
  /**
    * @brief  USBD_AUDIO_DataIn
    *         handle data IN Stage
    * @param  pdev: device instance
    * @param  epnum: endpoint index
    * @retval status
    */
  static uint8_t  USBD_AUDIO_DataIn(USBD_HandleTypeDef *pdev,
                                    uint8_t epnum)
  {
  
    /* Only OUT data are processed */
    return USBD_OK;
  }
  
  /**
    * @brief  USBD_AUDIO_EP0_RxReady
    *         handle EP0 Rx Ready event
    * @param  pdev: device instance
    * @retval status
    */
  static uint8_t  USBD_AUDIO_EP0_RxReady(USBD_HandleTypeDef *pdev)
  {
    USBD_AUDIO_HandleTypeDef   *haudio;
    haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
  
    if (haudio->control.cmd == AUDIO_REQ_SET_CUR) {
      /* In this driver, to simplify code, only SET_CUR request is managed */
  
      if (haudio->control.unit == AUDIO_OUT_STREAMING_CTRL) {
        ((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->MuteCtl(haudio->control.data[0]);
        haudio->control.cmd = 0U;
        haudio->control.len = 0U;
      }
    }
  
    return USBD_OK;
  }
  /**
    * @brief  USBD_AUDIO_EP0_TxReady
    *         handle EP0 TRx Ready event
    * @param  pdev: device instance
    * @retval status
    */
  static uint8_t  USBD_AUDIO_EP0_TxReady(USBD_HandleTypeDef *pdev)
  {
    /* Only OUT control data are processed */
    return USBD_OK;
  }
  /**
    * @brief  USBD_AUDIO_SOF
    *         handle SOF event
    * @param  pdev: device instance
    * @retval status
    */
  static uint8_t  USBD_AUDIO_SOF(USBD_HandleTypeDef *pdev)
  {
    return USBD_OK;
  }
  
  /**
    * @brief  USBD_AUDIO_SOF
    *         handle SOF event
    * @param  pdev: device instance
    * @retval status
    */
  void  USBD_AUDIO_Sync(USBD_HandleTypeDef *pdev, AUDIO_OffsetTypeDef offset)
  {
    uint32_t cmd = 0U;
    USBD_AUDIO_HandleTypeDef   *haudio;
    haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
  
    haudio->offset =  offset;
  
    if (haudio->rd_enable == 1U) {
      haudio->rd_ptr += (uint16_t)(AUDIO_TOTAL_BUF_SIZE / 2U);
  
      if (haudio->rd_ptr == AUDIO_TOTAL_BUF_SIZE) {
        /* roll back */
        haudio->rd_ptr = 0U;
      }
    }
  
    if (haudio->rd_ptr > haudio->wr_ptr) {
      if ((haudio->rd_ptr - haudio->wr_ptr) < AUDIO_OUT_PACKET) {
        cmd = AUDIO_TOTAL_BUF_SIZE / 2U + 4U;
      } else {
        if ((haudio->rd_ptr - haudio->wr_ptr) > (AUDIO_TOTAL_BUF_SIZE - AUDIO_OUT_PACKET)) {
          cmd = AUDIO_TOTAL_BUF_SIZE / 2U - 4U;
        }
      }
    } else {
      if ((haudio->wr_ptr - haudio->rd_ptr) < AUDIO_OUT_PACKET) {
        cmd = AUDIO_TOTAL_BUF_SIZE / 2U - 4U;
      } else {
        if ((haudio->wr_ptr - haudio->rd_ptr) > (AUDIO_TOTAL_BUF_SIZE - AUDIO_OUT_PACKET)) {
          cmd = AUDIO_TOTAL_BUF_SIZE / 2U + 4U;
        }
      }
    }
  
    if (haudio->offset == AUDIO_OFFSET_FULL) {
      ((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->AudioCmd(&haudio->buffer[0],
                                                           cmd,
                                                           AUDIO_CMD_PLAY);
      haudio->offset = AUDIO_OFFSET_NONE;
    }
  }
  
  /**
    * @brief  USBD_AUDIO_IsoINIncomplete
    *         handle data ISO IN Incomplete event
    * @param  pdev: device instance
    * @param  epnum: endpoint index
    * @retval status
    */
  static uint8_t  USBD_AUDIO_IsoINIncomplete(USBD_HandleTypeDef *pdev, uint8_t epnum)
  {
  
    return USBD_OK;
  }
  /**
    * @brief  USBD_AUDIO_IsoOutIncomplete
    *         handle data ISO OUT Incomplete event
    * @param  pdev: device instance
    * @param  epnum: endpoint index
    * @retval status
    */
  static uint8_t  USBD_AUDIO_IsoOutIncomplete(USBD_HandleTypeDef *pdev, uint8_t epnum)
  {
  
    return USBD_OK;
  }
  /**
    * @brief  USBD_AUDIO_DataOut
    *         handle data OUT Stage
    * @param  pdev: device instance
    * @param  epnum: endpoint index
    * @retval status
    */
  static uint8_t  USBD_AUDIO_DataOut(USBD_HandleTypeDef *pdev,
                                     uint8_t epnum)
  {
    USBD_AUDIO_HandleTypeDef   *haudio;
    haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
  
    if (epnum == AUDIO_OUT_EP) {
      /* Increment the Buffer pointer or roll it back when all buffers are full */
  
      haudio->wr_ptr += AUDIO_OUT_PACKET;
  
      if (haudio->wr_ptr == AUDIO_TOTAL_BUF_SIZE) {
        /* All buffers are full: roll back */
        haudio->wr_ptr = 0U;
  
        if (haudio->offset == AUDIO_OFFSET_UNKNOWN) {
          ((USBD_AUDIO_ItfTypeDef *)pdev->pUserData)->AudioCmd(&haudio->buffer[0],
                                                               AUDIO_TOTAL_BUF_SIZE / 2U,
                                                               AUDIO_CMD_START);
          haudio->offset = AUDIO_OFFSET_NONE;
        }
      }
  
      if (haudio->rd_enable == 0U) {
        if (haudio->wr_ptr == (AUDIO_TOTAL_BUF_SIZE / 2U)) {
          haudio->rd_enable = 1U;
        }
      }
  
      /* Prepare Out endpoint to receive next audio packet */
      USBD_LL_PrepareReceive(pdev, AUDIO_OUT_EP, &haudio->buffer[haudio->wr_ptr],
                             AUDIO_OUT_PACKET);
    }
  
    return USBD_OK;
  }
  
  /**
    * @brief  AUDIO_Req_GetCurrent
    *         Handles the GET_CUR Audio control request.
    * @param  pdev: instance
    * @param  req: setup class request
    * @retval status
    */
  static void AUDIO_REQ_GetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req)
  {
    USBD_AUDIO_HandleTypeDef   *haudio;
    haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
  
    memset(haudio->control.data, 0, 64U);
  
    /* Send the current mute state */
    USBD_CtlSendData(pdev, haudio->control.data, req->wLength);
  }
  
  /**
    * @brief  AUDIO_Req_SetCurrent
    *         Handles the SET_CUR Audio control request.
    * @param  pdev: instance
    * @param  req: setup class request
    * @retval status
    */
  static void AUDIO_REQ_SetCurrent(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req)
  {
    USBD_AUDIO_HandleTypeDef   *haudio;
    haudio = (USBD_AUDIO_HandleTypeDef *) pdev->pClassData;
  
    if (req->wLength) {
      /* Prepare the reception of the buffer over EP0 */
      USBD_CtlPrepareRx(pdev,
                        haudio->control.data,
                        req->wLength);
  
      haudio->control.cmd = AUDIO_REQ_SET_CUR;     /* Set the request value */
      haudio->control.len = (uint8_t)req->wLength; /* Set the request data length */
      haudio->control.unit = HIBYTE(req->wIndex);  /* Set the request target unit */
    }
  }
  
  
  /**
  * @brief  DeviceQualifierDescriptor
  *         return Device Qualifier descriptor
  * @param  length : pointer data length
  * @retval pointer to descriptor buffer
  */
  static uint8_t  *USBD_AUDIO_GetDeviceQualifierDesc(uint16_t *length)
  {
    *length = sizeof(USBD_AUDIO_DeviceQualifierDesc);
    return USBD_AUDIO_DeviceQualifierDesc;
  }
  
  /**
  * @brief  USBD_AUDIO_RegisterInterface
  * @param  fops: Audio interface callback
  * @retval status
  */
  uint8_t  USBD_AUDIO_RegisterInterface(USBD_HandleTypeDef   *pdev,
                                        USBD_AUDIO_ItfTypeDef *fops)
  {
    if (fops != NULL) {
      pdev->pUserData = fops;
    }
    return USBD_OK;
  }
  /**
    * @}
    */
  
  
  /**
    * @}
    */
  
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  