#!/bin/sh
#
# CPU Frequency Scaling manipulation tool
#
# Author: Adam Drzewiecki
# e-mail: A.Drzewiecki@ztpnet.pl
# WWW: http://drzewiecki.zgora.pl
#
# Last modified: 12 Oct 2008
#

# path to information about CPUs, located at SYSFS
CPUINFO="/sys/devices/system/cpu"

# some useful variables
CPUFREQ="cpufreq"
SCALING_GOVERNORS="$CPUFREQ/scaling_available_governors"
SCALING_FREQUENCIES="$CPUFREQ/scaling_available_frequencies"
SCALING_MIN="$CPUFREQ/scaling_min_freq"
SCALING_MAX="$CPUFREQ/scaling_max_freq"
SCALING_CUR="$CPUFREQ/scaling_cur_freq"
SCALING_GOV="$CPUFREQ/scaling_governor"
SCALING_SSP="$CPUFREQ/scaling_setspeed"
SCALING_DRV="$CPUFREQ/scaling_driver"
CPUINFO_MIN="$CPUFREQ/cpuinfo_min_freq"
CPUINFO_MAX="$CPUFREQ/cpuinfo_max_freq"

#
# Most of the operations are available only for user root
#
is_root() {
    if [ "$(id -u)" -ne "0" ]; then
	echo "you must be root to do that"
	exit -1
    fi
}

#
# Create a CPFreq'ed CPU's list
#
cpu_list() {
    CPUS=""
    for CPU in $CPUINFO/cpu* ; do
	# build a path to CPUFreq interface
	CFSPATH="$CPUINFO/$(basename $CPU)/$CPUFREQ"
	# if CPU have an interface CPUFreq, add it to list
	if [ -d "$CFSPATH" ]; then
	    if [ -z "$CPUS" ]; then
		CPUS="$(basename $CPU)"
	    else
		CPUS="$CPUS $(basename $CPU)"
	    fi
	fi
    done
}

#
# Create list of governors, compiled as a modules
#
modules_list() {
    MODULES=""
    # extract modules path from modules.dep, filter paths with "cpufreq_"
    for MODULE in $(cat /lib/modules/$(uname -r)/modules.dep | cut -f 1 -d ":" | grep "cpufreq_" ) ; do
	# take module filename without extension and take part after first occurence of "_" sign
	GOVNAME="$(basename $MODULE .ko | cut -f 2 -d _)"
	# "cpufreq_stats" is the only module name beginnning with "cpufreq_" which isn't a governor...
	if [ "$GOVNAME" != "stats" ]; then
	    if [ -z "$MODULES" ]; then
		MODULES="$GOVNAME"
	    else
		MODULES="$MODULES $GOVNAME"
	    fi
	fi 
    done
}

#
# Create governors list available for particular processor
#
# $1 - cpuN
#
governors_list() {
    if [ -f "$CPUINFO/$1/$SCALING_GOVERNORS" ]; then
	# create list of known governors
	GOVERNORS=""
	for GOVERNOR in $(cat $CPUINFO/$1/$SCALING_GOVERNORS) ; do
	    if [ -z "$GOVERNORS" ]; then
		GOVERNORS="$GOVERNOR"
	    else
		GOVERNORS="$GOVERNORS $GOVERNOR"
	    fi
	done

	# add governors available as a not loaded modules
	modules_list
	for MODULE in $MODULES ; do
	    # add governor name from MODULES only if it isn't on the governors list
	    if ! echo "$GOVERNORS" | grep -qs "$MODULE" ; then
		if [ -z "$GOVERNORS" ] ; then
		    GOVERNORS="$MODULE"
		else
		    GOVERNORS="$GOVERNORS $MODULE"
		fi
	    fi
	done
    fi
}

#
# Create list of available frequencies for particular processor
#
# $1 - cpuN
#
frequencies_list() {
    FREQUENCIES=""
    for FREQ in $(cat $CPUINFO/$1/$SCALING_FREQUENCIES) ; do
	if [ -z "$FREQUENCIES" ]; then
	    FREQUENCIES="$FREQ"
	else
	    FREQUENCIES="$FREQUENCIES $FREQ"
	fi
    done
}

#
# Show infromation about particular processor
#
# $1 - cpuN
#
show_processor() {
    CFSPATH="$CPUINFO/$1"
    if [ -d "$CFSPATH/$CPUFREQ" ]; then 
	echo -e "Processor \"$1\":\n"
	echo -e "Current frequency:\t$(cat $CFSPATH/$SCALING_CUR) kHz "
	echo -e "Frequency range:\t$(cat $CFSPATH/$SCALING_MIN)-$(cat $CFSPATH/$SCALING_MAX) kHz"
	echo -e "Current governor:\t$(cat $CFSPATH/$SCALING_GOV)"
	governors_list $1
	echo -e "Available governors:\t$GOVERNORS"
	echo -e "Scaling driver:\t\t$(cat $CFSPATH/$SCALING_DRV)"
	echo -e "Available frequencies:\t$(cat $CFSPATH/$CPUINFO_MIN)-$(cat $CFSPATH/$CPUINFO_MAX) kHz "
	frequencies_list $1
	echo -e "Frequencies list:\t$FREQUENCIES"
    fi
}

#
# Show real processor signature from given alias
#
# $1 - cpufreq file
#
show_real() {
    echo -n "\"$(readlink $1 | tr '/' '\n' | grep 'cpu[0-9]\+$')\""
}

#
# Show short information about aliased processor
#
# $1 - cpuN
#
show_alias() {
    CFSPATH="$CPUINFO/$1"    
    if [ -d "$CFSPATH/$CPUFREQ" ]; then 
	echo -n "Processor \"$1\": " 
	echo -n "alias to processor "
	show_real $CFSPATH/$CPUFREQ
    fi
}

#
# Shows information about CPUFreq-capable processor[s]
#
# $1 - cpuN
#
show_info() {
    if [ -z "$1" ]; then
	cpu_list
	CPULIST="$CPUS"
    else
	CPULIST="$1"
    fi

    if [ -z "$CPULIST" ]; then
	echo "No CPUFreq capable CPUs found"
    else
	for CPU in $CPULIST ; do
	    CFSPATH="$CPUINFO/$CPU"
	    if [ -d "$CFSPATH" ]; then
		if [ -d "$CFSPATH/$CPUFREQ" ]; then 
		    if [ ! -h "$CFSPATH/$CPUFREQ" ]; then
			show_processor $CPU
		    else
			show_alias $CPU
			if [ "$(echo $CPULIST | wc -w)" -lt "2" ]; then
			    echo
			    show_processor $(readlink $CFSPATH/$CPUFREQ | tr '/' '\n' | grep 'cpu[0-9]\+$') 
			fi 
		    fi
		else
		    echo "Processor \"$CPU\" haven't CPUFreq interface"
		fi
	    else
		echo "Processor \"$CPU\" doesn't exist"
	    fi
	    echo
	done
    fi
}

#
# Activating particular governor for a given processor[s]
#
# $1 - governor's name
# $2 - cpuN
# 
setup_governor() {
    if [ -z "$2" ]; then
	cpu_list
	CPUGOV="$CPUS"
    else
	CPUGOV="$2"
    fi
    
    for CPU in $CPUGOV; do
	CFSPATH="$CPUINFO/$CPU"
	if [ -d "$CFSPATH" ]; then
	    if [ -d "$CFSPATH/$CPUFREQ" ]; then
		echo -n "Set up governor \"$1\" for CPU \"$CPU\": "
		if [ ! -h "$CFSPATH/$CPUFREQ" -o "$(echo $CPUGOV | wc -w)" -lt "2" ]; then 
		    if echo "$1" >$CFSPATH/$SCALING_GOV 2>/dev/null ; then
			echo "success"
		    else
			echo "failed"
		    fi
		else
		    echo -n "skipped, \"$CPU\" is alias to processor "
		    show_real $CFSPATH/$CPUFREQ
		    echo
		fi
	    else
		echo "Processor \"$CPU\" haven't CPUFreq interface"
	    fi
	else
	    echo "Processor \"$CPU\" doesn't exist"
	fi
    done
}

#
# Set up particular frequency for a given processor
#
# $1 - frequency
# $2 - cpuN
# 
setup_frequency() {
    if [ -z "$2" ]; then
	cpu_list
	CPUFRQ="$CPUS"
    else
	CPUFRQ="$2"
    fi
    
    for CPU in $CPUFRQ; do
	CFSPATH="$CPUINFO/$CPU"
	if [ -d "$CFSPATH" ]; then
    	    if [ -d "$CFSPATH/$CPUGREQ" ]; then
		# only "userspace" governor can change current frequency
		[ "$(cat $CFSPATH/$SCALING_GOV)" != "userspace" ] && setup_governor "userspace" $CPU
		if [ -f "$CFSPATH/$SCALING_SSP" ] ; then
		    echo -n "Set up frequency for CPU \"$CPU\": "
		    if [ ! -h "$CFSPATH/$CPUFREQ" -o "$(echo $CPUGOV | wc -w)" -lt "2" ]; then 
			if echo "$1" >$CFSPATH/$SCALING_SSP 2>/dev/null ; then
			    echo "success, frequency set to $(cat $CFSPATH/$SCALING_CUR)"
			else
			    echo "failed"
			fi
		    else
			echo -n "skipped, \"$CPU\" is alias to processor "
			show_real $CFSPATH/$CPUFREQ
		    fi
		else
		    echo "Can't set \"$CPU\" frequency to \"$1\". Enable \"userspace\" governor in kernel"
		fi
	    else
		echo "Processor \"$CPU\" haven't CPUFreq interface"	    
	    fi
	else
	    echo "Processor \"$CPU\" doesn't exist"
	fi
    done
}

#
# Set up frequency range for a given processor[s]
#
# $1 - min freq
# $2 - max freq
# $3 - cpuN
# 
setup_range() {
    if [ -z "$3" ]; then
	cpu_list
	CPUGOV="$CPUS"
    else
	CPUGOV="$3"
    fi
    
    for CPU in $CPUGOV; do
	CFSPATH="$CPUINFO/$CPU"
	if [ -d "$CFSPATH" ]; then
	    if [ -d "$CFSPATH/$CPUFREQ" ]; then
		echo -n "Set up frequency range \"$1-$2\" for CPU \"$CPU\": "
		if [ ! -h "$CFSPATH/$CPUFREQ" -o "$(echo $CPUGOV | wc -w)" -lt "2" ]; then 
		    # higher frequency must be set as a first, then lower
		    if 	echo "$2" >$CFSPATH/$SCALING_MAX 2>/dev/null && \
			echo "$1" >$CFSPATH/$SCALING_MIN 2>/dev/null ; then
			echo -n "success"
		    else
			echo -n "failed"
		    fi
		    echo -e " ($(cat $CFSPATH/$SCALING_MIN)-$(cat $CFSPATH/$SCALING_MAX) kHz)" 
		else
		    echo -n "skipped, \"$CPU\" is alias to processor "
		    show_real $CFSPATH/$CPUFREQ
		fi
	    else
		echo "Processor \"$CPU\" haven't CPUFreq interface"
	    fi
	else
	    echo "Processor \"$CPU\" doesn't exist"
	fi
    done
}

#
# main()
#
case "$1" in
    i|info)
	show_info $2
	;;

    g|governor)
	is_root
	setup_governor $2 $3
	;;

    f|frequency)
	is_root
	setup_frequency $2 $3
	;;
	
    r|range)
	is_root
	setup_range $2 $3 $4
	;;
	
    h|help|*)
	echo
	echo "CPU Frequency Scaling tool"
	echo "(c) by Adam Drzewiecki"
	echo
	echo -e "usage:"
	echo -e "\t$(basename $0) i[nfo] [cpuN] - shows information about cpuN (or all)"
	echo -e "\t$(basename $0) g[overnor] name [cpuN] - set up governor \"name\" for cpuN (or all)"
	echo -e "\t$(basename $0) f[requency] frequency [cpuN] - set up current frequency for cpuN (or all)"
	echo -e "\t$(basename $0) r[ange] fmin fmax [cpuN] - set up frequency range for cpuN (or all)"
	echo -e "\t$(basename $0) h[elp] - shows this information"
	echo
	;;
esac