NVREG_XMITCTL_START
tx_ctrl |= NVREG_XMITCTL_START;
tx_ctrl &= ~NVREG_XMITCTL_START;
tx_status = readl(base + NvRegTransmitterControl) & NVREG_XMITCTL_START;
if (readl(base + NvRegTransmitterControl) & NVREG_XMITCTL_START) {