CGX_SMUX_RX_FRM_CTL_CTL_BCK
*rx_pause = !!(cfg & CGX_SMUX_RX_FRM_CTL_CTL_BCK);
cfg |= CGX_SMUX_RX_FRM_CTL_CTL_BCK;
cfg &= ~CGX_SMUX_RX_FRM_CTL_CTL_BCK;
cfg &= ~CGX_SMUX_RX_FRM_CTL_CTL_BCK;
cfg |= rx_pause ? CGX_SMUX_RX_FRM_CTL_CTL_BCK : 0x0;
cfg &= ~CGX_SMUX_RX_FRM_CTL_CTL_BCK;