LXR linux/drivers/media/dvb/ttpci/ttpci-eeprom.c

   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
  49static 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
  63static 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
  88static int ttpci_eeprom_read_encodedMAC(struct i2c_adapter *adapter, u8 * encodedMAC)
  89{
  90        int ret;
  91        u8 b0[] = { 0xcc };
  92
  93        struct i2c_msg msg[] = {
  94                { .addr = 0x50, .flags = 0, .buf = b0, .len = 1 },
  95                { .addr = 0x50, .flags = I2C_M_RD, .buf = encodedMAC, .len = 20 }
  96        };
  97
  98        /* dprintk("%s\n", __FUNCTION__); */
  99
 100        ret = i2c_transfer(adapter, msg, 2);
 101
 102        if (ret != 2)           /* Assume EEPROM isn't there */
 103                return (-ENODEV);
 104
 105        return 0;
 106}
 107
 108
 109int ttpci_eeprom_parse_mac(struct i2c_adapter *adapter, u8 *proposed_mac)
 110{
 111        int ret, i;
 112        u8 encodedMAC[20];
 113        u8 decodedMAC[6];
 114
 115        ret = ttpci_eeprom_read_encodedMAC(adapter, encodedMAC);
 116
 117        if (ret != 0) {         /* Will only be -ENODEV */
 118                dprintk("Couldn't read from EEPROM: not there?\n");
 119                memset(proposed_mac, 0, 6);
 120                return ret;
 121        }
 122
 123        ret = getmac_tt(decodedMAC, encodedMAC);
 124        if( ret != 0 ) {
 125                dprintk("adapter failed MAC signature check\n");
 126                dprintk("encoded MAC from EEPROM was " );
 127                for(i=0; i<19; i++) {
 128                        dprintk( "%.2x:", encodedMAC[i]);
 129                }
 130                dprintk("%.2x\n", encodedMAC[19]);
 131                memset(proposed_mac, 0, 6);
 132                return ret;
 133        }
 134
 135        memcpy(proposed_mac, decodedMAC, 6);
 136        dprintk("adapter has MAC addr = %.2x:%.2x:%.2x:%.2x:%.2x:%.2x\n",
 137                decodedMAC[0], decodedMAC[1], decodedMAC[2],
 138                decodedMAC[3], decodedMAC[4], decodedMAC[5]);
 139        return 0;
 140}
 141
 142EXPORT_SYMBOL(ttpci_eeprom_parse_mac);
 143
 144MODULE_LICENSE("GPL");
 145MODULE_AUTHOR("Ralph Metzler, Marcus Metzler, others");
 146MODULE_DESCRIPTION("Decode dvb_net MAC address from EEPROM of PCI DVB cards "
 147                "made by Siemens, Technotrend, Hauppauge");
 148