vxworks_pci函数注释

/***********************************************
PCI设备查找程序
vendorId:设备厂商号；
deviceId:设备号;
index:索引号;
*pBusNo:返回的总线号；
*pDeviceNo;返回的设备号；
*pFuncNo：返回的功能号；
************************************************/

STATUS pciFindDevice
    (
    int    vendorId,	/* vendor ID */
    int    deviceId,	/* device ID */
    int    index,	/* desired instance of device */
    int *  pBusNo,	/* bus number */
    int *  pDeviceNo,	/* device number */
    int *  pFuncNo	/* function number */
    )
    {
    STATUS status = ERROR;/*初始化状态为error*/
    BOOL   cont   = TRUE;/*定义cont为TRUE*/
    int    busNo;
    int    deviceNo;
    int    funcNo;
    UINT32 device;
    UINT32 vendor;
    UINT8  header;

    if (pciLibInitStatus != OK)			/* sanity check 检查初始化状态*/
        cont = FALSE;

    for (busNo = 0; cont == TRUE && busNo <= pciMaxBus; busNo++)/*查找总线号*/
        for (deviceNo = 0;
	     ((cont == TRUE) && (deviceNo < PCI_MAX_DEV));
	     ++deviceNo)											/*查找设备号*/
            for (funcNo = 0; cont == TRUE && funcNo < PCI_MAX_FUNC; funcNo++)/*查找功能号*/
		{
		/* avoid a special bus cycle 避免一个特殊的总线循环*/

		if ((deviceNo == 0x1f) && (funcNo == 0x07))
		    continue;/*结束当前循环开始下一个循环*/

		pciConfigInLong (busNo, deviceNo, funcNo, PCI_CFG_VENDOR_ID,
				 &vendor);

		/*
		 * If nonexistent device, skip to next, only look at
		 * vendor ID field for existence check
		 */

		if (((vendor & 0x0000ffff) == 0x0000FFFF) && (funcNo == 0))
		    break;

		device  = vendor >> 16;/*右移16位得到设备名*/
		device &= 0x0000FFFF;
		vendor &= 0x0000FFFF;/*厂商名等于低16位*/
		if ((vendor == (UINT32)vendorId) &&
		    (device == (UINT32)deviceId) &&
		    (index-- == 0))
		    {
		    *pBusNo	= busNo;
		    *pDeviceNo	= deviceNo;
		    *pFuncNo	= funcNo;
		    status	= OK;
		    cont	= FALSE;	/* terminate all loops */
		    continue;
		    }

		/* goto next if current device is single function */

		pciConfigInByte (busNo, deviceNo, funcNo, PCI_CFG_HEADER_TYPE, 
				 &header);
		if ((header & PCI_HEADER_MULTI_FUNC) != PCI_HEADER_MULTI_FUNC &&
		    funcNo == 0)
		    break;
		}

    return (status);
    }
	
	
	
	/*************************************************
	PCI读取函数
	busNo:总线号；
	deviceNo:设备号；
	funcNo:功能号；
	offset:偏移量；
	*pData：返回的数据;
	**************************************************/
	STATUS pciConfigInLong
    (
    int	busNo,     /* bus number */
    int	deviceNo,  /* device number */
    int	funcNo,    /* function number */
    int	offset,    /* offset into the configuration space */
    UINT32 * pData /* data read from the offset */
    )
    {
    int		 key;
    STATUS retStat = ERROR;
    UINT32 retval = 0;

    /* check for library initialization or unaligned access */

#ifdef PCI_CONFIG_OFFSET_NOCHECK
    if (pciLibInitStatus != OK)
	{
        return (retStat);
	}
#else
    if ((pciLibInitStatus != OK) || ((offset & (int)0x3) > 0) )
	{
        return (retStat);
	}
#endif

    key = intLock ();				/* mutual exclusion start 屏蔽中断互斥开始*/

    switch (pciConfigMech)
	{

        case PCI_MECHANISM_0:
            if (pciConfigRead (busNo, deviceNo, funcNo, offset, 4,
                                (void *)&retval) == ERROR)
		{
                retval = 0xffffffff;
		}
	    else
		{
		retStat = OK;
		}
            break;


	case PCI_MECHANISM_1:
	    PCI_OUT_LONG (pciConfigAddr0, 
		          pciConfigBdfPack (busNo, deviceNo, funcNo) |
		          (offset & 0xfc) | 0x80000000);
	    retval = PCI_IN_LONG (pciConfigAddr1);
	    retStat = OK;
	    break;

	case PCI_MECHANISM_2:
	    PCI_OUT_BYTE (pciConfigAddr0, 0xf0 | (funcNo << 1));
	    PCI_OUT_BYTE (pciConfigAddr1, busNo);
	    retval = PCI_IN_LONG (pciConfigAddr2 | ((deviceNo & 0x000f) << 8) |
				  (offset & 0xfc));
	    PCI_OUT_BYTE (pciConfigAddr0, 0);
	    retStat = OK;
	    break;

	default:
	    break;
	}

    intUnlock (key);				/* mutual exclusion stop 解除中断锁*/

    *pData = retval;

    return (retStat);
    }