text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Linux driver for digital TV devices equipped with B2C2 FlexcopII(b)/III
   * flexcop-eeprom.c - eeprom access methods (currently only MAC address reading)
   * see flexcop.c for copyright information
   */
  #include "flexcop.h"
  
  #if 0
  /*EEPROM (Skystar2 has one "24LC08B" chip on board) */
  static int eeprom_write(struct adapter *adapter, u16 addr, u8 *buf, u16 len)
  {
  	return flex_i2c_write(adapter, 0x20000000, 0x50, addr, buf, len);
  }
  
  static int eeprom_lrc_write(struct adapter *adapter, u32 addr,
  		u32 len, u8 *wbuf, u8 *rbuf, int retries)
  {
  int i;
  
  for (i = 0; i < retries; i++) {
  	if (eeprom_write(adapter, addr, wbuf, len) == len) {
  		if (eeprom_lrc_read(adapter, addr, len, rbuf, retries) == 1)
  			return 1;
  		}
  	}
  	return 0;
  }
  
  /* These functions could be used to unlock SkyStar2 cards. */
  
  static int eeprom_writeKey(struct adapter *adapter, u8 *key, u32 len)
  {
  	u8 rbuf[20];
  	u8 wbuf[20];
  
  	if (len != 16)
  		return 0;
  
  	memcpy(wbuf, key, len);
  	wbuf[16] = 0;
  	wbuf[17] = 0;
  	wbuf[18] = 0;
  	wbuf[19] = calc_lrc(wbuf, 19);
  	return eeprom_lrc_write(adapter, 0x3e4, 20, wbuf, rbuf, 4);
  }
  
  static int eeprom_readKey(struct adapter *adapter, u8 *key, u32 len)
  {
  	u8 buf[20];
  
  	if (len != 16)
  		return 0;
  
  	if (eeprom_lrc_read(adapter, 0x3e4, 20, buf, 4) == 0)
  		return 0;
  
  	memcpy(key, buf, len);
  	return 1;
  }
  
  static char eeprom_set_mac_addr(struct adapter *adapter, char type, u8 *mac)
  {
  	u8 tmp[8];
  
  	if (type != 0) {
  		tmp[0] = mac[0];
  		tmp[1] = mac[1];
  		tmp[2] = mac[2];
  		tmp[3] = mac[5];
  		tmp[4] = mac[6];
  		tmp[5] = mac[7];
  	} else {
  		tmp[0] = mac[0];
  		tmp[1] = mac[1];
  		tmp[2] = mac[2];
  		tmp[3] = mac[3];
  		tmp[4] = mac[4];
  		tmp[5] = mac[5];
  	}
  
  	tmp[6] = 0;
  	tmp[7] = calc_lrc(tmp, 7);
  
  	if (eeprom_write(adapter, 0x3f8, tmp, 8) == 8)
  		return 1;
  	return 0;
  }
  
  static int flexcop_eeprom_read(struct flexcop_device *fc,
  		u16 addr, u8 *buf, u16 len)
  {
  	return fc->i2c_request(fc,FC_READ,FC_I2C_PORT_EEPROM,0x50,addr,buf,len);
  }
  
  #endif
  
  static u8 calc_lrc(u8 *buf, int len)
  {
  	int i;
  	u8 sum = 0;
  	for (i = 0; i < len; i++)
  		sum = sum ^ buf[i];
  	return sum;
  }
  
  static int flexcop_eeprom_request(struct flexcop_device *fc,
  	flexcop_access_op_t op, u16 addr, u8 *buf, u16 len, int retries)
  {
  	int i,ret = 0;
  	u8 chipaddr =  0x50 | ((addr >> 8) & 3);
  	for (i = 0; i < retries; i++) {
  		ret = fc->i2c_request(&fc->fc_i2c_adap[1], op, chipaddr,
  			addr & 0xff, buf, len);
  		if (ret == 0)
  			break;
  	}
  	return ret;
  }
  
  static int flexcop_eeprom_lrc_read(struct flexcop_device *fc, u16 addr,
  		u8 *buf, u16 len, int retries)
  {
  	int ret = flexcop_eeprom_request(fc, FC_READ, addr, buf, len, retries);
  	if (ret == 0)
  		if (calc_lrc(buf, len - 1) != buf[len - 1])
  			ret = -EINVAL;
  	return ret;
  }
  
  /* JJ's comment about extended == 1: it is not presently used anywhere but was
   * added to the low-level functions for possible support of EUI64 */
  int flexcop_eeprom_check_mac_addr(struct flexcop_device *fc, int extended)
  {
  	u8 buf[8];
  	int ret = 0;
  
  	if ((ret = flexcop_eeprom_lrc_read(fc,0x3f8,buf,8,4)) == 0) {
  		if (extended != 0) {
  			err("TODO: extended (EUI64) MAC addresses aren't completely supported yet");
  			ret = -EINVAL;
  		} else
  			memcpy(fc->dvb_adapter.proposed_mac,buf,6);
  	}
  	return ret;
  }
  EXPORT_SYMBOL(flexcop_eeprom_check_mac_addr);
  