FM10K_TDT
buff[idx++] = fm10k_read_reg(hw, FM10K_TDT(i));
tail = fm10k_read_reg(hw, FM10K_TDT(ring->reg_idx));
fm10k_read_reg(hw, FM10K_TDT(tx_ring->reg_idx)),
fm10k_write_reg(hw, FM10K_TDT(reg_idx), 0);
ring->tail = &interface->uc_addr[FM10K_TDT(reg_idx)];