EMAC_RX_FBC_REG
uint32_t rx_count = sun4i_emac_read(sc, EMAC_RX_FBC_REG);
rx_count = sun4i_emac_read(sc, EMAC_RX_FBC_REG);
sun4i_emac_write(sc, EMAC_RX_FBC_REG, 0);