stub/i2c-stub-from-dump

#!/usr/bin/perl -w
#
# Copyright (C) 2007-2008  Jean Delvare <khali@linux-fr.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA  02110-1301, USA
#
# This script feeds the i2c-stub driver with dump data from a real
# I2C or SMBus chip. This can be useful when writing a driver for
# a device you do not have access to, but of which you have a dump.

use strict;
use vars qw($bus_nr @addr $err);

# Kernel version detection code by Mark M. Hoffman,
# copied from sensors-detect.
use vars qw(@kernel_version);

sub initialize_kernel_version
{
	`uname -r` =~ /(\d+)\.(\d+)\.(\d+)(.*)/;
	@kernel_version = ($1, $2, $3, $4);
}

sub kernel_version_at_least
{
	my ($vers, $plvl, $slvl) = @_;
	return 1 if ($kernel_version[0]  > $vers ||
	              ($kernel_version[0] == $vers && 
	                ($kernel_version[1]  > $plvl || 
	                  ($kernel_version[1] == $plvl && 
	                    ($kernel_version[2] >= $slvl)))));
	return 0;
}

# Find out the i2c bus number of i2c-stub
sub get_i2c_stub_bus_number
{
	my $nr;

	open(FH, "i2cdetect -l |") || die "Can't run i2cdetect";
	while (<FH>) {
		next unless m/^i2c-(\d+).*\tSMBus stub/;
		$nr = $1;
		last;
	}
	close(FH);

	return $nr;
}

# Unload i2c-stub if we need an address it doesn't offer
sub check_chip_addr {
	my $chip_addr_file = shift;
	my @addr = @{shift()};
	local $_;

	open(CHIP_ADDR, $chip_addr_file) || return;
	$_ = <CHIP_ADDR>;
	chomp;
	my %stub_addr = map { $_ => 1 } split ',';
	close(CHIP_ADDR);

	foreach my $addr (@addr) {
		unless (exists $stub_addr{$addr}) {
			print STDERR "Cycling i2c-stub to get the address we need\n";
			system("/sbin/rmmod", "i2c-stub");
			return;
		}
	}
}

# Load the required kernel drivers if needed
sub load_kernel_drivers
{
	local $_;
	my @addr = @{shift()};
	my $nr;

	# i2c-stub may be loaded without the address we want
	check_chip_addr("/sys/module/i2c_stub/parameters/chip_addr", \@addr);

	# Maybe everything is already loaded
	$nr = get_i2c_stub_bus_number();
	return $nr if defined $nr;

	system("/sbin/modprobe", "i2c-dev") == 0 || exit 1;
	if (kernel_version_at_least(2, 6, 19)) {
		system("/sbin/modprobe", "i2c-stub",
		       "chip_addr=".join(',', @addr)) == 0 || exit 1;
	} else {
		system("/sbin/modprobe", "i2c-stub") == 0 || exit 1;
	}
	# udev may take some time to create the device node
	if (!(-x "/sbin/udevadm" && system("/sbin/udevadm settle") == 0)
	 && !(-x "/sbin/udevsettle" && system("/sbin/udevsettle") == 0)) {
		sleep(1);
	}

	$nr = get_i2c_stub_bus_number();
	if (!defined($nr)) {
		print STDERR "Please load i2c-stub first\n";
		exit 2;
	}

	return $nr;
}

sub process_dump
{
	my ($addr, $dump) = @_;
	my $err = 0;
	my ($bytes, $words);

	open(DUMP, $dump) || die "Can't open $dump: $!\n";
 OUTER_LOOP:
	while (<DUMP>) {
		if (m/^([0-9a-f]0) ?[:|](( [0-9a-fX]{2}){16})/i) {
			# Byte dump
			my $offset = hex($1);
			my @values = split(/ /, $2);
			shift(@values);
			for (my $i = 0; $i < 16 && (my $val = shift(@values)); $i++) {
				next if $val =~ m/X/;
				if (system("i2cset", "-y", $bus_nr, $addr,
					   sprintf("0x\%02x", $offset+$i),
					   "0x$val", "b")) {
					$err = 3;
					last OUTER_LOOP;
				}
				$bytes++;
			}
		} elsif (m/^([0-9a-f][08]) ?[:|](( [0-9a-fX]{4}){8})/i) {
			# Word dump
			my $offset = hex($1);
			my @values = split(/ /, $2);
			shift(@values);
			for (my $i = 0; $i < 8 && (my $val = shift(@values)); $i++) {
				next if $val =~ m/X/;
				if (system("i2cset", "-y", $bus_nr, $addr,
					   sprintf("0x\%02x", $offset+$i),
					   "0x$val", "w")) {
					$err = 3;
					last OUTER_LOOP;
				}
				$words++;
			}
		}
	}
	close(DUMP);

	if ($bytes) {
		printf SAVEOUT "$bytes byte values written to \%d-\%04x\n",
			$bus_nr, $addr;
	}

	if ($words) {
		printf SAVEOUT "$words word values written to \%d-\%04x\n",
			$bus_nr, $addr;
	}

	if (!$err && !$bytes && !$words) {
		printf SAVEOUT "Only garbage found in dump file $dump\n";
		$err = 1;
	}

	return $err;
}

if ($>) {
	print "You must be root to use this script\n";
	exit 1;
}

if (@ARGV < 2) {
	print STDERR "Usage: i2c-stub-from-dump <addr>[,<addr>,...] <dump file> [<dump file> ...]\n";
	exit 1;
}

# Check the parameters
@addr = split(/,/, shift @ARGV);
foreach (@addr) {
	unless (m/^0x[0-7][0-9a-f]$/i) {
		print STDERR "Invalid address $_\n";
		exit 1;
	}
	$_ = oct $_;
}

if (@addr < @ARGV) {
	print STDERR "Fewer addresses than dumps provided\n";
	exit 4;
}

initialize_kernel_version();
if (@addr > 1 && !kernel_version_at_least(2, 6, 24)) {
	print STDERR "Multiple addresses not supported by this kernel version\n";
	exit 5;
}

$bus_nr = load_kernel_drivers(\@addr);

# We don't want to see the output of 256 i2cset
open(SAVEOUT, ">&STDOUT");
open(STDOUT, ">/dev/null");
foreach (@addr) {
	if (!@ARGV) {
		printf STDERR "Skipping \%d-\%04x, no dump file privided\n",
		       $bus_nr, $_;
		next;
	}
	$err = process_dump($_, shift @ARGV);
	last if $err;
}
close(STDOUT);

exit($err);