release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define dprintk(x...) do { printk(x); } while (0)
  43
  44
  45 static int check_mac_tt(u8 *buf)
  46 {
  47         int i;
  48         u16 tmp = 0xffff;
  49
  50         for (i = 0; i < 8; i++) {
  51                 tmp  = (tmp << 8) | ((tmp >> 8) ^ buf[i]);
  52                 tmp ^= (tmp >> 4) & 0x0f;
  53                 tmp ^= (tmp << 12) ^ ((tmp & 0xff) << 5);
  54         }
  55         tmp ^= 0xffff;
  56         return (((tmp >> 8) ^ buf[8]) | ((tmp & 0xff) ^ buf[9]));
  57 }
  58
  59 static int getmac_tt(u8 * decodedMAC, u8 * encodedMAC)
  60 {
  61         u8 xor[20] = { 0x72, 0x23, 0x68, 0x19, 0x5c, 0xa8, 0x71, 0x2c,
  62                        0x54, 0xd3, 0x7b, 0xf1, 0x9E, 0x23, 0x16, 0xf6,
  63                        0x1d, 0x36, 0x64, 0x78};
  64         u8 data[20];
  65         int i;
  66
  67         /* In case there is a sig check failure have the orig contents available */
  68         memcpy(data, encodedMAC, 20);
  69
  70         for (i = 0; i < 20; i++)
  71                 data[i] ^= xor[i];
  72         for (i = 0; i < 10; i++)
  73                 data[i] = ((data[2 * i + 1] << 8) | data[2 * i])
  74                         >> ((data[2 * i + 1] >> 6) & 3);
  75
  76         if (check_mac_tt(data))
  77                 return -ENODEV;
  78
  79         decodedMAC[0] = data[2]; decodedMAC[1] = data[1]; decodedMAC[2] = data[0];
  80         decodedMAC[3] = data[6]; decodedMAC[4] = data[5]; decodedMAC[5] = data[4];
  81         return 0;
  82 }
  83
  84 static int ttpci_eeprom_read_encodedMAC(struct i2c_adapter *adapter, u8 * encodedMAC)
  85 {
  86         int ret;
  87         u8 b0[] = { 0xcc };
  88
  89         struct i2c_msg msg[] = {
  90                 { .addr = 0x50, .flags = 0, .buf = b0, .len = 1 },
  91                 { .addr = 0x50, .flags = I2C_M_RD, .buf = encodedMAC, .len = 20 }
  92         };
  93
  94         /* dprintk("%s\n", __func__); */
  95
  96         ret = i2c_transfer(adapter, msg, 2);
  97
  98         if (ret != 2)           /* Assume EEPROM isn't there */
  99                 return (-ENODEV);
 100
 101         return 0;
 102 }
 103
 104
 105 int ttpci_eeprom_parse_mac(struct i2c_adapter *adapter, u8 *proposed_mac)
 106 {
 107         int ret, i;
 108         u8 encodedMAC[20];
 109         u8 decodedMAC[6];
 110
 111         ret = ttpci_eeprom_read_encodedMAC(adapter, encodedMAC);
 112
 113         if (ret != 0) {         /* Will only be -ENODEV */
 114                 dprintk("Couldn't read from EEPROM: not there?\n");
 115                 memset(proposed_mac, 0, 6);
 116                 return ret;
 117         }
 118
 119         ret = getmac_tt(decodedMAC, encodedMAC);
 120         if( ret != 0 ) {
 121                 dprintk("adapter failed MAC signature check\n");
 122                 dprintk("encoded MAC from EEPROM was " );
 123                 for(i=0; i<19; i++) {
 124                         dprintk( "%.2x:", encodedMAC[i]);
 125                 }
 126                 dprintk("%.2x\n", encodedMAC[19]);
 127                 memset(proposed_mac, 0, 6);
 128                 return ret;
 129         }
 130
 131         memcpy(proposed_mac, decodedMAC, 6);
 132         dprintk("adapter has MAC addr = %.2x:%.2x:%.2x:%.2x:%.2x:%.2x\n",
 133                 decodedMAC[0], decodedMAC[1], decodedMAC[2],
 134                 decodedMAC[3], decodedMAC[4], decodedMAC[5]);
 135         return 0;
 136 }
 137
 138 EXPORT_SYMBOL(ttpci_eeprom_parse_mac);
 139
 140 MODULE_LICENSE("GPL");
 141 MODULE_AUTHOR("Ralph Metzler, Marcus Metzler, others");
 142 MODULE_DESCRIPTION("Decode dvb_net MAC address from EEPROM of PCI DVB cards "
 143                 "made by Siemens, Technotrend, Hauppauge");