recipes-connectivity/mctp-controller-init/mctp-controller-init-v3/mctp-controller-init.sh

#!/bin/bash

# This script will bring up all MCTP link (i2c, i3c, USB), and assign local MCTP address (from 254 to lower EID) for them.

# Use single MCTP network ID 1 by default
readonly USE_SINGLE_NETWORK_ID='true'

get_next_net()
{
    existing=$(mctp link | awk '{print $8}')
    net=1
    while true; do
        if echo "$existing" | grep -E "^${net}$" >/dev/null; then
            net=$((net + 1))
        else
            echo ${net}
            return
        fi
    done
}

# Search unused EID from 254 to lower addresses
get_next_eid()
{
    if [ $# -ne 1 ]; then
      echo "Error: missing network ID parameter."
      exit 1
    fi

    net="$1"
    existing=$(mctp addr | grep "net $net" | awk '{print $2}')

    # Valid EID range: [8-254]
    eid=254
    while [ "$eid" -ge 8 ]; do
        if echo "$existing" | grep -E "^${eid}$" >/dev/null; then
            eid=$((eid - 1))
        else
            echo $eid
            return
        fi
    done

    echo "Error: all EID range [8-254] of net ${net} are already assigned"
    exit 1
}

# Wait 1 second for udevd to fully release the interface rename lock
sleep 1

mctp_ifname_lines=$(mctp link | grep -v 'dev lo')

while IFS= read -r line; do
  if [[ $line =~ ^dev\ (mctp[a-z0-9]+)\ index ]]; then
    ifname="${BASH_REMATCH[1]}"

    # Bring up MCTP link if it is down
    if [[ "$line" == *"down" ]]; then
      if ${USE_SINGLE_NETWORK_ID}; then
        net=1
      else
        net=$(get_next_net)
      fi

      echo "mctp link set ${ifname} up network $net"
      mctp link set "${ifname}" up network "${net}"
    fi

    # Assign local MCTP EID if it has no address yet
    mctp_addr_line=$(mctp addr show "${ifname}" )
    if [[ ${mctp_addr_line} != *"eid "* ]]; then
      eid=$(get_next_eid "${net}")
      echo "mctp addr add ${eid} dev ${ifname}"
      mctp addr add "${eid}" dev "${ifname}"
    fi
  fi

done <<< "${mctp_ifname_lines}"