1 /*
2 Retrieve encoded MAC address from 24C16 serial 2-wire EEPROM,
3 decode it and store it in the associated adapter struct for
4 use by dvb_net.c
5
6 This card appear to have the 24C16 write protect held to ground,
7 thus permitting normal read/write operation. Theoretically it
8 would be possible to write routines to burn a different (encoded)
9 MAC address into the EEPROM.
10
11 Robert Schlabbach GMX
12 Michael Glaum KVH Industries
13 Holger Waechtler Convergence
14
15 Copyright (C) 2002-2003 Ralph Metzler <rjkm@metzlerbros.de>
16 Metzler Brothers Systementwicklung GbR
17
18 This program is free software; you can redistribute it and/or modify
19 it under the terms of the GNU General Public License as published by
20 the Free Software Foundation; either version 2 of the License, or
21 (at your option) any later version.
22
23 This program is distributed in the hope that it will be useful,
24 but WITHOUT ANY WARRANTY; without even the implied warranty of
25 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
26 GNU General Public License for more details.
27
28 You should have received a copy of the GNU General Public License
29 along with this program; if not, write to the Free Software
30 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31
32 */
33
34 #include <asm/errno.h>
35 #include <linux/init.h>
36 #include <linux/module.h>
37 #include <linux/string.h>
38 #include <linux/i2c.h>
39
40 #include "ttpci-eeprom.h"
41
42 #if 1
43 #define dprintk(x...) do { printk(x); } while (0)
44 #else
45 #define dprintk(x...) do { } while (0)
46 #endif
47
48
check_mac_tt(u8 * buf)49 static int check_mac_tt(u8 *buf)
50 {
51 int i;
52 u16 tmp = 0xffff;
53
54 for (i = 0; i < 8; i++) {
55 tmp = (tmp << 8) | ((tmp >> 8) ^ buf[i]);
56 tmp ^= (tmp >> 4) & 0x0f;
57 tmp ^= (tmp << 12) ^ ((tmp & 0xff) << 5);
58 }
59 tmp ^= 0xffff;
60 return (((tmp >> 8) ^ buf[8]) | ((tmp & 0xff) ^ buf[9]));
61 }
62
getmac_tt(u8 * decodedMAC,u8 * encodedMAC)63 static int getmac_tt(u8 * decodedMAC, u8 * encodedMAC)
64 {
65 u8 xor[20] = { 0x72, 0x23, 0x68, 0x19, 0x5c, 0xa8, 0x71, 0x2c,
66 0x54, 0xd3, 0x7b, 0xf1, 0x9E, 0x23, 0x16, 0xf6,
67 0x1d, 0x36, 0x64, 0x78};
68 u8 data[20];
69 int i;
70
71 /* In case there is a sig check failure have the orig contents available */
72 memcpy(data, encodedMAC, 20);
73
74 for (i = 0; i < 20; i++)
75 data[i] ^= xor[i];
76 for (i = 0; i < 10; i++)
77 data[i] = ((data[2 * i + 1] << 8) | data[2 * i])
78 >> ((data[2 * i + 1] >> 6) & 3);
79
80 if (check_mac_tt(data))
81 return -ENODEV;
82
83 decodedMAC[0] = data[2]; decodedMAC[1] = data[1]; decodedMAC[2] = data[0];
84 decodedMAC[3] = data[6]; decodedMAC[4] = data[5]; decodedMAC[5] = data[4];
85 return 0;
86 }
87
ttpci_eeprom_decode_mac(u8 * decodedMAC,u8 * encodedMAC)88 int ttpci_eeprom_decode_mac(u8 *decodedMAC, u8 *encodedMAC)
89 {
90 u8 xor[20] = { 0x72, 0x23, 0x68, 0x19, 0x5c, 0xa8, 0x71, 0x2c,
91 0x54, 0xd3, 0x7b, 0xf1, 0x9E, 0x23, 0x16, 0xf6,
92 0x1d, 0x36, 0x64, 0x78};
93 u8 data[20];
94 int i;
95
96 memcpy(data, encodedMAC, 20);
97
98 for (i = 0; i < 20; i++)
99 data[i] ^= xor[i];
100 for (i = 0; i < 10; i++)
101 data[i] = ((data[2 * i + 1] << 8) | data[2 * i])
102 >> ((data[2 * i + 1] >> 6) & 3);
103
104 if (check_mac_tt(data))
105 return -ENODEV;
106
107 decodedMAC[0] = data[2];
108 decodedMAC[1] = data[1];
109 decodedMAC[2] = data[0];
110 decodedMAC[3] = data[6];
111 decodedMAC[4] = data[5];
112 decodedMAC[5] = data[4];
113 return 0;
114 }
115 EXPORT_SYMBOL(ttpci_eeprom_decode_mac);
116
ttpci_eeprom_read_encodedMAC(struct i2c_adapter * adapter,u8 * encodedMAC)117 static int ttpci_eeprom_read_encodedMAC(struct i2c_adapter *adapter, u8 * encodedMAC)
118 {
119 int ret;
120 u8 b0[] = { 0xcc };
121
122 struct i2c_msg msg[] = {
123 { .addr = 0x50, .flags = 0, .buf = b0, .len = 1 },
124 { .addr = 0x50, .flags = I2C_M_RD, .buf = encodedMAC, .len = 20 }
125 };
126
127 /* dprintk("%s\n", __func__); */
128
129 ret = i2c_transfer(adapter, msg, 2);
130
131 if (ret != 2) /* Assume EEPROM isn't there */
132 return (-ENODEV);
133
134 return 0;
135 }
136
137
ttpci_eeprom_parse_mac(struct i2c_adapter * adapter,u8 * proposed_mac)138 int ttpci_eeprom_parse_mac(struct i2c_adapter *adapter, u8 *proposed_mac)
139 {
140 int ret, i;
141 u8 encodedMAC[20];
142 u8 decodedMAC[6];
143
144 ret = ttpci_eeprom_read_encodedMAC(adapter, encodedMAC);
145
146 if (ret != 0) { /* Will only be -ENODEV */
147 dprintk("Couldn't read from EEPROM: not there?\n");
148 memset(proposed_mac, 0, 6);
149 return ret;
150 }
151
152 ret = getmac_tt(decodedMAC, encodedMAC);
153 if( ret != 0 ) {
154 dprintk("adapter failed MAC signature check\n");
155 dprintk("encoded MAC from EEPROM was " );
156 for(i=0; i<19; i++) {
157 dprintk( "%.2x:", encodedMAC[i]);
158 }
159 dprintk("%.2x\n", encodedMAC[19]);
160 memset(proposed_mac, 0, 6);
161 return ret;
162 }
163
164 memcpy(proposed_mac, decodedMAC, 6);
165 dprintk("adapter has MAC addr = %.2x:%.2x:%.2x:%.2x:%.2x:%.2x\n",
166 decodedMAC[0], decodedMAC[1], decodedMAC[2],
167 decodedMAC[3], decodedMAC[4], decodedMAC[5]);
168 return 0;
169 }
170
171 EXPORT_SYMBOL(ttpci_eeprom_parse_mac);
172
173 MODULE_LICENSE("GPL");
174 MODULE_AUTHOR("Ralph Metzler, Marcus Metzler, others");
175 MODULE_DESCRIPTION("Decode dvb_net MAC address from EEPROM of PCI DVB cards "
176 "made by Siemens, Technotrend, Hauppauge");
177