RDFAR
sh_eth_write(ndev, mdp->rx_desc_dma, RDFAR);
u32 count = (sh_eth_read(ndev, RDFAR) -
add_reg(RDFAR);
[RDFAR] = 0x00cc,
[RDFAR] = 0x0044,
sh_eth_write(ndev, 0, RDFAR);
[RDFAR] = 0x0034,