#!/usr/bin/perl -w

$cpu_path = '/sys/devices/system/cpu/cpu0/cpufreq/';
$all_cpu  = '/sys/devices/system/cpu/cpu[0-9]/cpufreq/';
chomp ($avl_governors = `cat $cpu_path/scaling_available_governors`);
chomp ($avl_frequencies = `cat $cpu_path/scaling_available_frequencies`);

# Only current status desired
if (! @ARGV)
{
   @cpus = `cat $all_cpu/cpuinfo_cur_freq`;
   print map { "Current frequency : $_" } @cpus;

   chomp ($cur_governor = `cat $cpu_path/scaling_governor`);
   print <<_END_OF_INFO_;
Current governor  : $cur_governor
Avail. governors  : $avl_governors

_END_OF_INFO_
}
# Set current frequency or scaling governor
else
{
   if ($ARGV[0] =~ /^\d+$/)
   {
      $req_speed = $ARGV[0];
      if ($avl_frequencies !~ /\b$req_speed\b/)
      {
         die("Requested frequency $req_speed is not valid\n",
             "Available frequencies are: $avl_frequencies\n\n");
      }
      @cpus = `ls $all_cpu/scaling_max_freq`;
      foreach $cpu (@cpus)
      {
         system("echo $req_speed >> $cpu");
      }
   }
   else 
   {
      $req_governor = $ARGV[0];
      if ($avl_governors !~ /$req_governor/)
      {
         die("Requested governor $req_governor is not valid\n",
             "Available governors are: $avl_governors\n\n");
      }
      @cpus = `ls $all_cpu/scaling_governor`;
      foreach $cpu (@cpus)
      {
         system("echo $req_governor >> $cpu");
      }
   }
}