#!/bin/sh
# $Id: cpufreq,v 1.4 2010/02/17 18:44:54 friedman Exp $

# Display current frequency values, or set new thresholds

initialize()
{
  sys=/sys/devices/system/cpu

  # These are the min/max values which the core is capable of.
  read cpuinfo_min_freq  < $sys/cpu0/cpufreq/cpuinfo_min_freq
  read cpuinfo_max_freq  < $sys/cpu0/cpufreq/cpuinfo_max_freq

  read scaling_min_freq  < $sys/cpu0/cpufreq/scaling_min_freq
  read scaling_max_freq  < $sys/cpu0/cpufreq/scaling_max_freq
  read scaling_cur_freq  < $sys/cpu0/cpufreq/scaling_cur_freq

  read scaling_available_frequencies < $sys/cpu0/cpufreq/scaling_available_frequencies
}

display_all()
{
  echo cpuinfo_min_freq=$cpuinfo_min_freq
  echo cpuinfo_max_freq=$cpuinfo_max_freq
  echo
  echo scaling_min_freq=$scaling_min_freq
  echo scaling_max_freq=$scaling_max_freq
  echo scaling_cur_freq=$scaling_cur_freq
  echo
  echo scaling_available=$scaling_available_frequencies
}

check_avail()
{
  case " $scaling_available_frequencies " in
    *" $1 "* ) return 0 ;;
  esac

  echo Available frequencies: $scaling_available_frequencies 1>&2
  exit 1
}

set_freq()
{
  param=$1
  new=$2

  check_avail $new

  for cpu in $sys/cpu*/cpufreq ; do
    echo $new > $cpu/$param || return $?
  done

  echo $param=$new
}

min()
{
  case $1 in
    ''  ) echo $scaling_min_freq ;;
    min ) set_freq scaling_min_freq $cpuinfo_min_freq ;;
    max ) set_freq scaling_min_freq $cpuinfo_max_freq ;;
    *   ) set_freq scaling_min_freq $1        ;;
  esac
}

max()
{
  case $1 in
    ''  ) echo $scaling_max_freq ;;
    min ) set_freq scaling_max_freq $cpuinfo_min_freq ;;
    max ) set_freq scaling_max_freq $cpuinfo_max_freq ;;
    *   ) set_freq scaling_max_freq $1        ;;
  esac
}

usage()
{
  usage="Usage: ${0##*/} {options}

Options are:
-h, --help                   This help.
-a, --all                    Display all cpu frequency parameters
--min {freq}                 Display current min frequency, or set it.
--max {freq}                 Display current max frequency, or set it.
--avail                      Display available frequencies.

The optional frequency parameter to \`--min' and \`--max' can be the
literals \"min\" or \"max\" to indicate the minimum or maximum possible
frequency, respectively."

  echo "$usage"
  exit 0
}

main()
{
  initialize

  case $1 in
    --* ) x=${1#--} ; shift ; set x "$x" "$@" ; shift ;;
    -*  ) x=${1#-}  ; shift ; set x "$x" "$@" ; shift ;;
  esac

  case $1:$2 in
    h:*  | h*:*  ) usage       ;;
    a:*  | all:* ) display_all ;;

    avail*:*     ) echo $scaling_available_frequencies ;;
    :            ) echo $scaling_cur_freq ;;

    min:*        ) min $2 ;;
    max:*        ) max $2 ;;
    [0-9]*:      ) max $1 ;;
  esac
}

main "$@"

# eof