#!/bin/sh

# Get the mtd device number (mtdX)
findmtd() {
  m="$(grep -xl "$1" /sys/class/mtd/*/name)"
  m="${m%/name}"
  m="${m##*/}"
  echo "${m}"
}

# Get the ubi device number (ubiX_Y)
findubi() {
  u="$(grep -xl "$1" /sys/class/ubi/ubi?/subsystem/ubi*/name)"
  u="${u%/name}"
  u="${u##*/}"
  echo "${u}"
}

ubi_rw() {
  rwmtd="$(findmtd "${reqmtd}")"
  rw="${rwmtd#mtd}"
  ubidev="/dev/ubi${rw}"

  # Create a ubi volume of size 4MB, that is the current size of the rwfs image
  vol="$(findubi "${name}")"
  if [ -z "${vol}" ]; then
    ubimkvol "${ubidev}" -N "${name}" -s 4MiB
  fi
}

case "$1" in
  ubirw)
    reqmtd="$2"
    name="$3"
    ubi_rw
    ;;
  *)
    echo "Invalid argument"
    exit 1
    ;;
esac
rc=$?
if [ ${rc} -ne 0 ]; then
  echo "$0: error ${rc}"
  exit ${rc}
fi