MD_CA_Busy
tc_writel(MD_CA_Busy | (mii_id << 5) | (regnum & 0x1f), &tr->MD_CA);
while (tc_readl(&tr->MD_CA) & MD_CA_Busy) {
tc_writel(MD_CA_Busy | MD_CA_Wr | (mii_id << 5) | (regnum & 0x1f),
while (tc_readl(&tr->MD_CA) & MD_CA_Busy) {