ET_RX_NRING
for (n = 0; n < ET_RX_NRING; ++n) {
if (ring_idx >= ET_RX_NRING) {
struct et_rxdesc_ring sc_rx_ring[ET_RX_NRING];
struct et_rxbuf_data sc_rx_data[ET_RX_NRING];
#define ET_RX_NSTAT (ET_RX_NRING * ET_RX_NDESC)