1#!/usr/bin/perl -w
2
3use Getopt::Std;
4
5use constant MINROMSIZE => 8192;
6use constant MAXROMSIZE => 262144;
7
8use constant PCI_PTR_LOC => 0x18;	# from beginning of ROM
9use constant PCI_HDR_SIZE => 0x18;
10use constant PNP_PTR_LOC => 0x1a;	# from beginning of ROM
11use constant PNP_HDR_SIZE => 0x20;
12use constant PNP_CHKSUM_OFF => 0x9;	# bytes from beginning of PnP header
13use constant PNP_DEVICE_OFF => 0x10;	# bytes from beginning of PnP header
14use constant PCI_VEND_ID_OFF => 0x4;	# bytes from beginning of PCI header
15use constant PCI_DEV_ID_OFF => 0x6;	# bytes from beginning of PCI header
16use constant PCI_SIZE_OFF => 0x10;	# bytes from beginning of PCI header
17
18use constant UNDI_PTR_LOC => 0x16;	# from beginning of ROM
19use constant UNDI_HDR_SIZE => 0x16;
20use constant UNDI_CHKSUM_OFF => 0x05;
21
22use strict;
23
24use vars qw(%opts);
25
26use bytes;
27
28sub getromsize ($) {
29	my ($romref) = @_;
30	my $i;
31
32	print STDERR "BIOS extension ROM Image did not start with 0x55 0xAA\n"
33		if (substr($$romref, 0, 2) ne "\x55\xaa");
34	my $size = ord(substr($$romref, 2, 1)) * 512;
35	for ($i = MINROMSIZE; $i < MAXROMSIZE and $i < $size; $i *= 2) { }
36	print STDERR "$size is a strange size for a boot ROM\n"
37		if ($size > 0 and $i > $size);
38	return ($size);
39}
40
41sub addident ($) {
42	my ($romref) = @_;
43
44	return (0) unless (my $s = $opts{'i'});
45	# include the terminating NUL byte too
46	$s .= "\x00";
47	my $len = length($s);
48	# Put the identifier in only if the space is blank
49	my $pos = length($$romref) - $len - 2;
50	return (0) if (substr($$romref, $pos, $len) ne ("\xFF" x $len));
51	substr($$romref, $pos, $len) = $s;
52	return ($pos);
53}
54
55sub pcipnpheaders ($$) {
56	my ($romref, $identoffset) = @_;
57	my ($pci_hdr_offset, $pnp_hdr_offset);
58
59	$pci_hdr_offset = unpack('v', substr($$romref, PCI_PTR_LOC, 2));
60	$pnp_hdr_offset = unpack('v', substr($$romref, PNP_PTR_LOC, 2));
61	# Sanity checks
62	if ($pci_hdr_offset < PCI_PTR_LOC + 2
63		or $pci_hdr_offset > length($$romref) - PCI_HDR_SIZE
64		or $pnp_hdr_offset < PNP_PTR_LOC + 2
65		or $pnp_hdr_offset > length($$romref) - PNP_HDR_SIZE
66		or substr($$romref, $pci_hdr_offset, 4) ne 'PCIR'
67		or substr($$romref, $pnp_hdr_offset, 4) ne '$PnP') {
68		$pci_hdr_offset = $pnp_hdr_offset = 0;
69	} else {
70		printf "PCI header at %#x and PnP header at %#x\n",
71			$pci_hdr_offset, $pnp_hdr_offset;
72	}
73	if ($pci_hdr_offset > 0) {
74		my ($pci_vendor_id, $pci_device_id);
75		# if no -p option, just report what's there
76		if (!defined($opts{'p'})) {
77			$pci_vendor_id = unpack('v', substr($$romref, $pci_hdr_offset+PCI_VEND_ID_OFF, 2));
78			$pci_device_id = unpack('v', substr($$romref, $pci_hdr_offset+PCI_DEV_ID_OFF, 2));
79			printf "PCI Vendor ID %#x Device ID %#x\n",
80				$pci_vendor_id, $pci_device_id;
81		} else {
82			substr($$romref, $pci_hdr_offset + PCI_SIZE_OFF, 2)
83				= pack('v', length($$romref) / 512);
84			($pci_vendor_id, $pci_device_id) = split(/,/, $opts{'p'});
85			substr($$romref, $pci_hdr_offset+PCI_VEND_ID_OFF, 2)
86				= pack('v', oct($pci_vendor_id)) if ($pci_vendor_id);
87			substr($$romref, $pci_hdr_offset+PCI_DEV_ID_OFF, 2)
88				= pack('v', oct($pci_device_id)) if ($pci_device_id);
89		}
90	}
91	if ($pnp_hdr_offset > 0 and defined($identoffset)) {
92		# Point to device id string at end of ROM image
93		substr($$romref, $pnp_hdr_offset+PNP_DEVICE_OFF, 2)
94			= pack('v', $identoffset);
95		substr($$romref, $pnp_hdr_offset+PNP_CHKSUM_OFF, 1) = "\x00";
96		my $sum = unpack('%8C*', substr($$romref, $pnp_hdr_offset,
97			PNP_HDR_SIZE));
98		substr($$romref, $pnp_hdr_offset+PNP_CHKSUM_OFF, 1) = chr(256 - $sum);
99	}
100}
101
102sub undiheaders ($) {
103	my ($romref) = @_;
104	my ($undi_hdr_offset);
105
106	$undi_hdr_offset = unpack('v', substr($$romref, UNDI_PTR_LOC, 2));
107	# Sanity checks
108	if ($undi_hdr_offset < UNDI_PTR_LOC + 2
109		or $undi_hdr_offset > length($$romref) - UNDI_HDR_SIZE
110		or substr($$romref, $undi_hdr_offset, 4) ne 'UNDI') {
111		$undi_hdr_offset = 0;
112	} else {
113		printf "UNDI header at %#x\n", $undi_hdr_offset;
114	}
115	if ($undi_hdr_offset > 0) {
116		substr($$romref, $undi_hdr_offset+UNDI_CHKSUM_OFF, 1) = "\x00";
117		my $sum = unpack('%8C*', substr($$romref, $undi_hdr_offset,
118			UNDI_HDR_SIZE));
119		substr($$romref, $undi_hdr_offset+UNDI_CHKSUM_OFF, 1) = chr(256 - $sum);
120	}
121}
122
123sub writerom ($$) {
124	my ($filename, $romref) = @_;
125
126	open(R, ">$filename") or die "$filename: $!\n";
127	print R $$romref;
128	close(R);
129}
130
131sub checksum ($) {
132	my ($romref) = @_;
133
134	substr($$romref, 6, 1) = "\x00";
135	my $sum = unpack('%8C*', $$romref);
136	substr($$romref, 6, 1) = chr(256 - $sum);
137	# Double check
138	$sum = unpack('%8C*', $$romref);
139	if ($sum != 0) {
140		print "Checksum fails\n"
141	} elsif ($opts{'v'}) {
142		print "Checksum ok\n";
143	}
144}
145
146sub makerom () {
147	my ($rom, $romsize);
148
149	getopts('3xi:p:s:v', \%opts);
150	$ARGV[0] or die "Usage: $0 [-s romsize] [-i ident] [-p vendorid,deviceid] [-x] [-3] rom-file\n";
151	open(R, $ARGV[0]) or die "$ARGV[0]: $!\n";
152	# Read in the whole ROM in one gulp
153	my $filesize = read(R, $rom, MAXROMSIZE+1);
154	close(R);
155	defined($filesize) and $filesize >= 3 or die "Cannot get first 3 bytes of file\n";
156	print "$filesize bytes read\n" if $opts{'v'};
157	# If PXE image, just fill the length field and write it out
158	if ($opts{'x'}) {
159		substr($rom, 2, 1) = chr((length($rom) + 511) / 512);
160		&writerom($ARGV[0], \$rom);
161		return;
162	}
163	# Size specified with -s overrides value in 3rd byte in image
164	# -s 0 means round up to next 512 byte block
165	if (defined($opts{'s'})) {
166		if (($romsize = oct($opts{'s'})) <= 0) {
167			# NB: This roundup trick only works on powers of 2
168			$romsize = ($filesize + 511) & ~511
169		}
170	} else {
171		$romsize = &getromsize(\$rom);
172		# 0 put there by *loader.S means makerom should pick the size
173		if ($romsize == 0) {
174			# Shrink romsize down to the smallest power of two that will do
175			for ($romsize = MAXROMSIZE;
176				$romsize > MINROMSIZE and $romsize >= 2*$filesize;
177				$romsize /= 2) { }
178		}
179	}
180	if ($filesize > $romsize) {
181		print STDERR "ROM size of $romsize not big enough for data, ";
182		# NB: This roundup trick only works on powers of 2
183		$romsize = ($filesize + 511) & ~511;
184		print "will use $romsize instead\n"
185	}
186	# Pad with 0xFF to $romsize
187	$rom .= "\xFF" x ($romsize - length($rom));
188	if ($romsize >= 128 * 1024) {
189		print "Warning: ROM size exceeds extension BIOS limit\n";
190	}
191	substr($rom, 2, 1) = chr(($romsize / 512) % 256);
192	print "ROM size is $romsize\n" if $opts{'v'};
193	my $identoffset = &addident(\$rom);
194	&pcipnpheaders(\$rom, $identoffset);
195	&undiheaders(\$rom);
196	# 3c503 requires last two bytes to be 0x80
197	substr($rom, MINROMSIZE-2, 2) = "\x80\x80"
198		if ($opts{'3'} and $romsize == MINROMSIZE);
199	&checksum(\$rom);
200	&writerom($ARGV[0], \$rom);
201}
202
203sub modrom () {
204	my ($rom);
205
206	getopts('p:v', \%opts);
207	$ARGV[0] or die "Usage: $0 [-p vendorid,deviceid] rom-file\n";
208	open(R, $ARGV[0]) or die "$ARGV[0]: $!\n";
209	# Read in the whole ROM in one gulp
210	my $filesize = read(R, $rom, MAXROMSIZE+1);
211	close(R);
212	defined($filesize) and $filesize >= 3 or die "Cannot get first 3 bytes of file\n";
213	print "$filesize bytes read\n" if $opts{'v'};
214	&pcipnpheaders(\$rom);
215	&undiheaders(\$rom);
216	&checksum(\$rom);
217	&writerom($ARGV[0], \$rom);
218}
219
220# Main routine. See how we were called and behave accordingly
221if ($0 =~ m:modrom(\.pl)?$:) {
222	&modrom();
223} else {
224	&makerom();
225}
226exit(0);
227