You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/oreboot/src/soc/src/amd/rome
    
    the code of the file until where you have to start completion: pub mod hsmp;
use hsmp::HSMP;

use crate::amd::common::{df::FabricTopology, mp::mpmailbox::MPMailbox};

pub struct SOC {
    hsmp: HSMP,
    // TODO: rename these when we know what they do
    mp0: MPMailbox<8>,
    mp1: MPMailbox<8>,
    mp2: MPMailbox<8>,
    mp3: MPMailb
    
    pub fn init(&mut self, w: &mut impl core::fmt::Write) -> Result<(), &'static str> {
        let mps = [
            &self.mp0,
            &self.mp1,
            &self.mp2,
            &self.mp3,
            &self.hsmp.mailbox,
        ];
        for mp in mps.iter() {
            match mp.test(42) {
                Ok(v) => {
                    write!(w, "mp result: {:x?}\r\n", v).unwrap();
                }
                Err(e) => {
                    write!(w, "mp test(42) error: {:x?}\r\n", e).unwrap();
                }
            }
            match mp.smu_version() {
                Ok(v) => {
                    write!(w, "mp smu version result: {:x?}\r\n", v).unwrap();
                }
                Err(e) => {
                    write!(w, "mp smu version error: {:x?}\r\n", e).unwrap();
                }
            }
        }

        match self.hsmp.interface_version() {
            Ok(v) => {
                write!(w, "HSMP interface version result: {:x?}\r\n", v).unwrap();
            }
            Err(e) => {
                write!(w, "HSMP interface version error: {:x?}\r\n", e).unwrap();
            }
        }
        let topology = FabricTopology::new();
        write!(w, "Topology: {:?}\r\n", topology).unwrap();
        Ok(())
    }