riocm_cmp_exch
if (!riocm_cmp_exch(ch, RIO_CM_CHAN_BOUND, RIO_CM_LISTEN))
if (!riocm_cmp_exch(ch, RIO_CM_IDLE, RIO_CM_CONNECT)) {
riocm_cmp_exch(ch, RIO_CM_CONNECT, RIO_CM_IDLE);