drivers/media/common/b2c2/flexcop-eeprom.c

// 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);