/*
    Retrieve encoded MAC address from 24C16 serial 2-wire EEPROM,
    decode it and store it in the associated adapter struct for
    use by dvb_net.c

    This code was tested on TT-Budget/WinTV-NOVA-CI PCI boards with
    Atmel and ST Microelectronics EEPROMs.

    This card appear to have the 24C16 write protect held to ground,
    thus permitting normal read/write operation. Theoretically it
    would be possible to write routines to burn a different (encoded)
    MAC address into the EEPROM.

    Robert Schlabbach	GMX
    Michael Glaum	KVH Industries
    Holger Waechtler	Convergence

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/    

#include <asm/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>

#include "dvb_i2c.h"
#include "dvb_functions.h"

#if 1
#define dprintk(x...) printk(x)
#else
#define dprintk(x...)
#endif


static
int ttpci_eeprom_read_encodedMAC (struct dvb_i2c_bus *i2c, u8 * encodedMAC )
{
	int ret;
	u8 b0 [] = { 0xd4 };
	struct i2c_msg msg [] = { { addr: 0x50, flags: 0, buf: b0, len: 1 },
		   { addr: 0x50, flags: I2C_M_RD, buf: encodedMAC, len: 6 } };

	dprintk ("%s\n", __FUNCTION__);

	ret = i2c->xfer (i2c, msg, 2);

	if (ret != 2) // Assume EEPROM isn't there
		return( -ENODEV );

	return 0;
}

static
void decodeMAC (u8 *decodedMAC, const u8* encodedMAC)
{
	u8 ormask0[3] = { 0x54, 0x7B, 0x9E };
        u8 ormask1[3] = { 0xD3, 0xF1, 0x23 };
	u8 low;
	u8 high;
	u8 shift;
	int i;

	decodedMAC[0] = 0x00;
        decodedMAC[1] = 0xD0;
        decodedMAC[2] = 0x5C;

	for (i=0; i<3; i++) { 
		low = encodedMAC[ 2*i ] ^ ormask0[i];
		high = encodedMAC[ 2*i+1 ] ^ ormask1[i];
		shift = ( high >> 6 ) & 0x3;

		decodedMAC[5-i] = ((high<<8) | low) >> shift;
	}

}


int ttpci_eeprom_parse_mac (struct dvb_i2c_bus *i2c)
{
	int ret;
	u8 encodedMAC[6];
	u8 decodedMAC[6];

	ret = ttpci_eeprom_read_encodedMAC(i2c, encodedMAC);

	if (ret != 0) { // Will only be -ENODEV
		dprintk("Couldn't read from EEPROM: not there?\n");
		memset(i2c->adapter->proposed_mac, 0, 6); 
		return ret;
	}

	decodeMAC(decodedMAC, encodedMAC);
	memcpy(i2c->adapter->proposed_mac, decodedMAC, 6);

	dprintk("%s adapter %i has MAC addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
		i2c->adapter->name, i2c->adapter->num,
		decodedMAC[0],decodedMAC[1],decodedMAC[2],
		decodedMAC[3],decodedMAC[4],decodedMAC[5]);
	dprintk("encoded MAC was %02x:%02x:%02x:%02x:%02x:%02x\n",
		encodedMAC[0],encodedMAC[1],encodedMAC[2],
		encodedMAC[3],encodedMAC[4],encodedMAC[5]);
	return 0;
}