基于OHCI的USB主机 —— USB设备枚举

USB设备接入以后，必须进行设备枚举，得到设备参数，设置设备运行配置等参数，下面的代码就是对U盘设备进行枚举的过程。
因为没有使用操作系统，所以函数使用状态迁移的方式完成枚举，该函数在主循环中被调用。

/**
* USB设备枚举处理
* @return 当前枚举处理的状态
*/
short usbEnumDev(void)
{
unsigned short i, oldState;
unsigned char cc, *pBuf, epBulkIn, epBulkOut;

if (!isUsbConnected())
{
enumDev.state = ENUM_DEV_IDLE;
return USB_DEV_NOT_CONNECTED;
}

oldState = enumDev.state;
switch (enumDev.state)
{
case ENUM_DEV_IDLE:
if (usbTimer >= 200)
{
//对硬件进行初始化，端口开电
ohciHardInit();
usbTimer = 0;
enumDev.state = ENUM_DEV_IDLE_DALAY;
}
break;

case ENUM_DEV_IDLE_DALAY:
//进行端口复位
ohciPortReset(0);

usbTimer = 0;
enumDev.errReason = 0;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_RESET_ING;
break;

case ENUM_DEV_RESET_ING:
if (ohciIsPortResetOver(0))// == OCHI_PORT_RESET_OVER)
{
usbTimer = 0;
enumDev.state = ENUM_DEV_WAIT_RESET_OVER;
}
if (usbTimer >= 200)
{
enumDev.errReason = DEV_ERROR_RESET_TIME_OUT;
enumDev.state =ENUM_DEV_OVER;
}
break;

case ENUM_DEV_WAIT_RESET_OVER:
//端口复位完成后延时120ms，然后进行端口初始化
if (usbTimer <= 12) break;
ohciPortInit(0);
usbTimer = 0;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_SEND_DEV_DESC_0;

break;

case ENUM_DEV_SEND_DEV_DESC_0:
usbInfoSetAddr(0);

//从地址0，端口0取得设备描述符
usbGetDeviceDesc(usbBuf);

usbTimer = 0;
enumDev.newState = ENUM_DEV_SET_ADDRESS;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_WAIT_CMD_OVER;
break;

case ENUM_DEV_SET_ADDRESS:
//为USB设备设置新的地址
usbSetAddress(usbBuf, 2);

usbTimer = 0;
enumDev.newState = ENUM_DEV_SEND_DEV_DESC_1;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_WAIT_CMD_OVER;
break;

case ENUM_DEV_SEND_DEV_DESC_1:
//从新地址，端口0取得设备描述符
usbGetDeviceDesc(usbBuf);

usbTimer = 0;
enumDev.newState = ENUM_DEV_FILL_DESC_DEV;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_WAIT_CMD_OVER;
break;

case ENUM_DEV_FILL_DESC_DEV:
//得到了端口描述符
bytesCopy((BYTE *)&usbDeviceInfo.devDesc, (BYTE *)usbBuf, sizeof(DEVICE_DESC));

usbTimer = 0;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_GET_DESC_CFG;
break;

case ENUM_DEV_GET_DESC_CFG:
//取得配置描述符集合
usbGetConfigDesc(usbBuf);

usbTimer = 0;
enumDev.newState = ENUM_DEV_FILL_DESC_SET;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_WAIT_CMD_OVER;
break;

case ENUM_DEV_FILL_DESC_SET:
pBuf = usbBuf;
//取得返回数据中的配置描述符
bytesCopy((BYTE *)&usbDeviceInfo.cfgDesc, pBuf, sizeof(CFG_DESC));

//取得返回数据中的接口描述符
pBuf += 9;
bytesCopy((BYTE *)&usbDeviceInfo.intfDesc, pBuf, sizeof(INTF_DESC));

//取得返回数据中的端点描述符
pBuf += 9;
for(i = 0; i < usbDeviceInfo.intfDesc.bEndPoints; i++)
{
bytesCopy((BYTE *)&usbDeviceInfo.epDesc[i], pBuf, sizeof(ED_DESC));
if (usbDeviceInfo.epDesc[i].bAttr == 0x02)
{
if ((usbDeviceInfo.epDesc[i].bEPAdd & 0x80) == 0x80)
epBulkIn = usbDeviceInfo.epDesc[i].bEPAdd & 0x0F;
else
epBulkOut = usbDeviceInfo.epDesc[i].bEPAdd & 0x0F;
}

pBuf += 7;
}

//保存得到的批量端口信息
usbInfoSetBulkPort(epBulkIn, epBulkOut);

usbTimer = 0;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_SET_CONFIGURATION;
break;

case ENUM_DEV_SET_CONFIGURATION:
//设置设备配置值
usbSetConfiguration(usbBuf);

usbTimer = 0;
enumDev.newState = ENUM_DEV_GET_CONFIGURATION;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_WAIT_CMD_OVER;
break;

case ENUM_DEV_GET_CONFIGURATION:
//取得设备配置值
usbGetConfiguration(usbBuf);

usbTimer = 0;
enumDev.newState = ENUM_DEV_CHECK_CONFIG;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_WAIT_CMD_OVER;
break;

case ENUM_DEV_CHECK_CONFIG:
//检查设备配置是否正确
if (usbBuf[0] != 1)
{
enumDev.errReason = DEV_ERROR_CONFIGURATION;
enumDev.state =ENUM_DEV_OVER;
break;
}

usbTimer = 0;
enumDev.oldState = enumDev.state;
enumDev.state = ENUM_DEV_OVER;
break;

case ENUM_DEV_WAIT_CMD_OVER:
//命令执行完毕
if (usbIsCmdOver() == USB_CMD_OVER)
{
cc = checkGenTd();
if (cc != 0)
{
if (cc == CC_STALL)
{
usbClearFeature(2, 0);
break;
}
else
{
enumDev.errReason = DEV_ERROR_TD;
enumDev.state =ENUM_DEV_OVER;
break;
}
}

enumDev.state = enumDev.newState;
}

//命令执行超时，则重新初始化
if (usbTimer >= 200)
{
ohciHardDisable();
usbTimer = 0;
enumDev.state = ENUM_DEV_IDLE;
}
break;

case ENUM_DEV_OVER:
break;
default:
enumDev.state = ENUM_DEV_IDLE;
}

return enumDev.state;
}