(USB HID) In/Out Report 收發 Function

在紀錄 In/Out Report 收發之前先來看一下一個struct

 typedef struct _Device_cb
 {
   uint8_t  (*Init)         (void *pdev , uint8_t cfgidx);
   uint8_t  (*DeInit)       (void *pdev , uint8_t cfgidx);
  /* Control Endpoints*/
   uint8_t  (*Setup)        (void *pdev , USB_SETUP_REQ  *req);
   uint8_t  (*EP0_TxSent)   (void *pdev );
   uint8_t  (*EP0_RxReady)  (void *pdev );
   /* Class Specific Endpoints*/
   uint8_t  (*DataIn)       (void *pdev , uint8_t epnum);
   uint8_t  (*DataOut)      (void *pdev , uint8_t epnum);
   uint8_t  (*SOF)          (void *pdev);
   uint8_t  (*IsoINIncomplete)  (void *pdev);
   uint8_t  (*IsoOUTIncomplete)  (void *pdev);   

   uint8_t  *(*GetConfigDescriptor)( uint8_t speed , uint16_t *length);
 #ifdef USB_OTG_HS_CORE
   uint8_t  *(*GetOtherConfigDescriptor)( uint8_t speed , uint16_t *length);
 #endif

 #ifdef USB_SUPPORT_USER_STRING_DESC
   uint8_t  *(*GetUsrStrDescriptor)( uint8_t speed ,uint8_t index,  uint16_t *length);
 #endif  

 } USBD_Class_cb_TypeDef;

這邊有特別註解 Control Endpoint， Class Specific Endpoint，理解翻譯就是Control Endpoint 即是所謂的Endpoint 0

在USB協定中，一定是透過Endpoint 0，而且一個裝置只能有一個，而且一定要支援。

它一次最大能傳的資料大小為64 bytes，並且是雙向傳輸。基本上一個USB裝置一插上電腦，電腦就會透過Endpoint 0來問一些資料。

根據USB2.0規格，Host必須保留10%的頻寬給Control傳輸。

而Class Specific Endpoint則是我定義 In/Out Report 需要使用的Function，在USB HID Init 時我會初始化我的Endpoint

 static uint8_t  USBD_HID_Init (void  *pdev,
                                uint8_t cfgidx)
 {

   /* Open EP IN */
   DCD_EP_Open(pdev,
               HID_IN_EP,
               HID_IN_PACKET,
               USB_OTG_EP_INT);

   /* Open EP OUT */
   DCD_EP_Open(pdev,
               HID_OUT_EP,
               HID_OUT_PACKET,
               USB_OTG_EP_INT);

   DCD_EP_PrepareRx(pdev, HID_OUT_EP, WRReport_buf, USB_HID_RECEIVE_FRAME_SIZE);

   return USBD_OK;
 }

在Window API理頭，主要是利用 WriteFile/ReadFile 跟 HidD_GetInputReport / HidD_SetOutputReport 來收發資料。

在Firmware裡頭對應 WriteFile/ReadFile 的是 Class Specific Endpoint

而對應 HidD_GetInputReport / HidD_SetOutputReport 則是透過 Endpoint 0去對Firmware 做控制。

GetInputReport / SetOutputReport 在 Firmeware 需要在 USBD_HID_Setup 裡頭加上 Set/Get Report的Case

 static uint8_t  USBD_HID_Setup (void  *pdev, USB_SETUP_REQ *req)
 {
   uint8_t USBD_HID_Report_LENGTH = ;
   uint16_t len = ;
   uint8_t  *pbuf = NULL;

   switch (req->bmRequest & USB_REQ_TYPE_MASK)
   {
   case USB_REQ_TYPE_CLASS :
     switch (req->bRequest)
     {

     case HID_REQ_SET_PROTOCOL:
       USBD_HID_Protocol = (uint8_t)(req->wValue);
       break;

     case HID_REQ_GET_PROTOCOL:
       USBD_CtlSendData (pdev,
                         (uint8_t *)&USBD_HID_Protocol, );
       break;

     case HID_REQ_SET_IDLE:
       USBD_HID_IdleState = (uint8_t)(req->wValue >> );
       break;

     case HID_REQ_GET_IDLE:
       USBD_CtlSendData (pdev, (uint8_t *)&USBD_HID_IdleState, );
       break;

     case HID_REQ_SET_REPORT:
       /* HidD_SetOutputReport 1-byte = Report ID (IN) */
       flag = ;
       USBD_HID_Report_ID = (uint8_t)(req->wValue);
       USBD_HID_Report_LENGTH = (uint8_t)(req->wLength);
       USBD_CtlPrepareRx (pdev, WRReport_buf, USBD_HID_Report_LENGTH);
       break;  

     case HID_REQ_GET_REPORT:
       /* HidD_GetInputReport 1-byte = Report ID (OUT) */
       flag = ;
       WRReport_buf[] = 0x11;
       WRReport_buf[] = 0x22;
       WRReport_buf[] = 0x33;
       WRReport_buf[] = 0x44;
       WRReport_buf[] = 0x55;
       WRReport_buf[] = 0x66;
       WRReport_buf[] = 0x77;
       WRReport_buf[] = 0x88;
       USBD_CtlSendData (pdev, (uint8_t *)&WRReport_buf, ); // to pc
       break; 

     default:
       USBD_CtlError (pdev, req);
       return USBD_FAIL;
     }
     break;

   case USB_REQ_TYPE_STANDARD:
     switch (req->bRequest)
     {
     case USB_REQ_GET_DESCRIPTOR:
       if( req->wValue >>  == HID_REPORT_DESC)
       {
             len = MIN(CUSTOMHID_SIZ_REPORT_DESC , req->wLength);
             pbuf = CustomHID_ReportDescriptor;
         //pbuf = HID_MOUSE_ReportDesc;

       }
       else if( req->wValue >>  == HID_DESCRIPTOR_TYPE)
       {
 //#ifdef USB_OTG_HS_INTERNAL_DMA_ENABLED
 //        pbuf = USBD_HID_Desc;
 //#else
 //        pbuf = USBD_HID_CfgDesc + 0x12;
 //#endif
         pbuf = USBD_HID_CfgDesc + 0x12;
         len = MIN(USB_HID_DESC_SIZ , req->wLength);
       }
       USBD_CtlSendData (pdev, pbuf, len);
       break;
     case USB_REQ_GET_INTERFACE :
       USBD_CtlSendData (pdev, (uint8_t *)&USBD_HID_AltSet, );

       break;

     case USB_REQ_SET_INTERFACE :
       USBD_HID_AltSet = (uint8_t)(req->wValue);
       break;
     }
   }
   return USBD_OK;
 }

這邊提及一下Firmware 發送 Class Specific Endpoint In/Out Report 是利用

DCD_EP_Tx (pdev, HID_IN_EP, report, len); // In Report
DCD_EP_PrepareRx(pdev, HID_OUT_EP, WRReport_buf, HID_OUT_PACKET);