SIBA_PCICORE_MDIO_CTL
siba_pcicore_write_4(spc, SIBA_PCICORE_MDIO_CTL, 0x80 | 0x2);
if (siba_pcicore_read_4(spc, SIBA_PCICORE_MDIO_CTL) & 0x100)
siba_pcicore_write_4(spc, SIBA_PCICORE_MDIO_CTL, 0);