CVMX_PEXP_NPEI_CTL_PORT0
npei_ctl_port.u64 = cvmx_read_csr(CVMX_PEXP_NPEI_CTL_PORT0);
cvmx_write_csr(CVMX_PEXP_NPEI_CTL_PORT0, npei_ctl_port.u64);