bmi_ctl
union bmi_ctl bmi_ctl;
bmi_ctl.value = nitrox_read_csr(ndev, offset);
bmi_ctl.s.max_pkt_len = 0xff;
bmi_ctl.s.nps_free_thrsh = 0xff;
bmi_ctl.s.nps_hdrq_thrsh = 0x7a;
nitrox_write_csr(ndev, offset, bmi_ctl.value);