release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/media/dvb/b2c2/flexcop-eeprom.c

   1 /*
   2  * Linux driver for digital TV devices equipped with B2C2 FlexcopII(b)/III
   3  * flexcop-eeprom.c - eeprom access methods (currently only MAC address reading)
   4  * see flexcop.c for copyright information
   5  */
   6 #include "flexcop.h"
   7
   8
   9 static u8 calc_lrc(u8 *buf, int len)
  10 {
  11         int i;
  12         u8 sum = 0;
  13         for (i = 0; i < len; i++)
  14                 sum = sum ^ buf[i];
  15         return sum;
  16 }
  17
  18 static int flexcop_eeprom_request(struct flexcop_device *fc,
  19         flexcop_access_op_t op, u16 addr, u8 *buf, u16 len, int retries)
  20 {
  21         int i,ret = 0;
  22         u8 chipaddr =  0x50 | ((addr >> 8) & 3);
  23         for (i = 0; i < retries; i++) {
  24                 ret = fc->i2c_request(&fc->fc_i2c_adap[1], op, chipaddr,
  25                         addr & 0xff, buf, len);
  26                 if (ret == 0)
  27                         break;
  28         }
  29         return ret;
  30 }
  31
  32 static int flexcop_eeprom_lrc_read(struct flexcop_device *fc, u16 addr,
  33                 u8 *buf, u16 len, int retries)
  34 {
  35         int ret = flexcop_eeprom_request(fc, FC_READ, addr, buf, len, retries);
  36         if (ret == 0)
  37                 if (calc_lrc(buf, len - 1) != buf[len - 1])
  38                         ret = -EINVAL;
  39         return ret;
  40 }
  41
  42 /* JJ's comment about extended == 1: it is not presently used anywhere but was
  43  * added to the low-level functions for possible support of EUI64 */
  44 int flexcop_eeprom_check_mac_addr(struct flexcop_device *fc, int extended)
  45 {
  46         u8 buf[8];
  47         int ret = 0;
  48
  49         if ((ret = flexcop_eeprom_lrc_read(fc,0x3f8,buf,8,4)) == 0) {
  50                 if (extended != 0) {
  51                         err("TODO: extended (EUI64) MAC addresses aren't "
  52                                 "completely supported yet");
  53                         ret = -EINVAL;
  54                 } else
  55                         memcpy(fc->dvb_adapter.proposed_mac,buf,6);
  56         }
  57         return ret;
  58 }
  59 EXPORT_SYMBOL(flexcop_eeprom_check_mac_addr);