#!/usr/bin/perl
use Fcntl;

# Are we forcing dual IDA?; if the FID below is IDA, this must be true
$ida=0;

# FID and VID to set
$fidvid=0x915;

# save existing governor
$governor = `cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor`;
chomp $governor;

# save existing MSRs
$cpu0_config = `rdmsr -p0 -d 0x1a0`;
$cpu1_config = `rdmsr -p1 -d 0x1a0`;
$cpu0_fidvid = `rdmsr -p0 -d 0x199`;
$cpu1_fidvid = `rdmsr -p1 -d 0x199`;

# is second core running?
$core1=1;

local $SIG{INT} = sub { exit(); };

# set userspace governor
`echo "userspace" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor`;
`echo "userspace" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor`;

# force set the clock frequency and voltage
if($ida){
    my $trying=1;
    $ret = `rdmsr -d 0x1a0`;
    $ret &= 0x100000;
    if($ret){
        print STDERR "Cannot set IDA; bit locked by BIOS\n";
        exit(1);
    }

    # turn off speedstep and IDA
    `wrmsr 0x1a0 0x1364862489`;

    # request ida
    `wrmsr 0x199 $fidvid`;

    # disable second core
    `echo 0 > /sys/devices/system/cpu/cpu1/online`;
    $core1=0;

    # toggle speedstep until the request sticks
    while($trying){
        `wrmsr 0x1a0 0x1364872489`;
        `wrmsr 0x1a0 0x1364862489`;

        $trying=0;
        $ret = `rdmsr -d 0x198`;
        $ret &= 0xffff;
        if( ($ret+0) != ($fidvid+0) ){
            $trying=1;
        }

        if($trying){
            print STDERR "retrying IDA request\n";
            sleep 1;
        }else{


            print STDERR "IDA request successful\n";
        }
    }

    # reenable second core
    `echo 1 > /sys/devices/system/cpu/cpu1/online`;
    $core1=1;
}else{

    # turn off speedstep and IDA
    `wrmsr -p0 0x1a0 0x1364862489`;
    `wrmsr -p1 0x1a0 0x1364862489`;

    # request vid/fid on both processors
    `wrmsr -p0 0x199 $fidvid`;
    `wrmsr -p1 0x199 $fidvid`;

    # turn on speedstep
    `wrmsr -p0 0x1a0 0x1364872489`;
    `wrmsr -p1 0x1a0 0x1364872489`;

    # verify they set
    $ret = `rdmsr -p0 -d 0x198`;
    $ret &= 0xffff;
    if( ($ret+0) != ($fidvid+0) ){
	print STDERR "could not set fid/vid on CPU0\n";
	exit(1);
    }

    $ret = `rdmsr -p1 -d 0x198`;
    $ret &= 0xffff;
    if( ($ret+0) != ($fidvid+0) ){
	print STDERR "could not set fid/vid on CPU1\n";
	exit(1);
    }

    # turn off speedstep
    # `wrmsr -p0 0x1a0 0x1364862489`;
    # `wrmsr -p1 0x1a0 0x1364862489`;
}

while(1){
    sleep;
}

END {

if($core1==0){
    `echo 1 > /sys/devices/system/cpu/cpu1/online`;
    sleep 1;
}
`wrmsr -p0 0x199 $cpu0_fidvid`;
`wrmsr -p1 0x199 $cpu1_fidvid`;
`wrmsr -p0 0x1a0 $cpu0_config`;
`wrmsr -p1 0x1a0 $cpu1_config`;
`echo $governor > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor`;
`echo $governor > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor`;
};