U3D_DEVICE_CONF
mtu3_writel(mbase, U3D_DEVICE_CONF, 0);
speed = SSUSB_DEV_SPEED(mtu3_readl(mbase, U3D_DEVICE_CONF));
dev_conf = mtu3_readl(mbase, U3D_DEVICE_CONF);
mtu3_writel(mbase, U3D_DEVICE_CONF, dev_conf);