aboutsummaryrefslogtreecommitdiff
path: root/drivers/media/dvb/ttpci/ttpci-eeprom.c
blob: 1f31e91195b0c6817718d5ca4f6658247064416f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/*
    Retrieve encoded MAC address from 24C16 serial 2-wire EEPROM,
    decode it and store it in the associated adapter struct for
    use by dvb_net.c

    This card appear to have the 24C16 write protect held to ground,
    thus permitting normal read/write operation. Theoretically it
    would be possible to write routines to burn a different (encoded)
    MAC address into the EEPROM.

    Robert Schlabbach	GMX
    Michael Glaum	KVH Industries
    Holger Waechtler	Convergence

    Copyright (C) 2002-2003 Ralph Metzler <rjkm@metzlerbros.de>
			    Metzler Brothers Systementwicklung GbR

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <asm/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/i2c.h>

#include "ttpci-eeprom.h"

#if 1
#define dprintk(x...) do { printk(x); } while (0)
#else
#define dprintk(x...) do { } while (0)
#endif


static int check_mac_tt(u8 *buf)
{
	int i;
	u16 tmp = 0xffff;

	for (i = 0; i < 8; i++) {
		tmp  = (tmp << 8) | ((tmp >> 8) ^ buf[i]);
		tmp ^= (tmp >> 4) & 0x0f;
		tmp ^= (tmp << 12) ^ ((tmp & 0xff) << 5);
	}
	tmp ^= 0xffff;
	return (((tmp >> 8) ^ buf[8]) | ((tmp & 0xff) ^ buf[9]));
}

static int getmac_tt(u8 * decodedMAC, u8 * encodedMAC)
{
	u8 xor[20] = { 0x72, 0x23, 0x68, 0x19, 0x5c, 0xa8, 0x71, 0x2c,
		       0x54, 0xd3, 0x7b, 0xf1, 0x9E, 0x23, 0x16, 0xf6,
		       0x1d, 0x36, 0x64, 0x78};
	u8 data[20];
	int i;

	/* In case there is a sig check failure have the orig contents available */
	memcpy(data, encodedMAC, 20);

	for (i = 0; i < 20; i++)
		data[i] ^= xor[i];
	for (i = 0; i < 10; i++)
		data[i] = ((data[2 * i + 1] << 8) | data[2 * i])
			>> ((data[2 * i + 1] >> 6) & 3);

	if (check_mac_tt(data))
		return -ENODEV;

	decodedMAC[0] = data[2]; decodedMAC[1] = data[1]; decodedMAC[2] = data[0];
	decodedMAC[3] = data[6]; decodedMAC[4] = data[5]; decodedMAC[5] = data[4];
	return 0;
}

static int ttpci_eeprom_read_encodedMAC(struct i2c_adapter *adapter, u8 * encodedMAC)
{
	int ret;
	u8 b0[] = { 0xcc };

	struct i2c_msg msg[] = {
		{ .addr = 0x50, .flags = 0, .buf = b0, .len = 1 },
		{ .addr = 0x50, .flags = I2C_M_RD, .buf = encodedMAC, .len = 20 }
	};

	/* dprintk("%s\n", __FUNCTION__); */

	ret = i2c_transfer(adapter, msg, 2);

	if (ret != 2)		/* Assume EEPROM isn't there */
		return (-ENODEV);

	return 0;
}


int ttpci_eeprom_parse_mac(struct i2c_adapter *adapter, u8 *proposed_mac)
{
	int ret, i;
	u8 encodedMAC[20];
	u8 decodedMAC[6];

	ret = ttpci_eeprom_read_encodedMAC(adapter, encodedMAC);

	if (ret != 0) {		/* Will only be -ENODEV */
		dprintk("Couldn't read from EEPROM: not there?\n");
		memset(proposed_mac, 0, 6);
		return ret;
	}

	ret = getmac_tt(decodedMAC, encodedMAC);
	if( ret != 0 ) {
		dprintk("adapter failed MAC signature check\n");
		dprintk("encoded MAC from EEPROM was " );
		for(i=0; i<19; i++) {
			dprintk( "%.2x:", encodedMAC[i]);
		}
		dprintk("%.2x\n", encodedMAC[19]);
		memset(proposed_mac, 0, 6);
		return ret;
	}

	memcpy(proposed_mac, decodedMAC, 6);
	dprintk("adapter has MAC addr = %.2x:%.2x:%.2x:%.2x:%.2x:%.2x\n",
		decodedMAC[0], decodedMAC[1], decodedMAC[2],
		decodedMAC[3], decodedMAC[4], decodedMAC[5]);
	return 0;
}

EXPORT_SYMBOL(ttpci_eeprom_parse_mac);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ralph Metzler, Marcus Metzler, others");
MODULE_DESCRIPTION("Decode dvb_net MAC address from EEPROM of PCI DVB cards "
		"made by Siemens, Technotrend, Hauppauge");