/*
 * This module implements the final step of modifying the EEPROM
 * for the desired configuration.
 */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <usb.h>
#include "../libftmini/eeprom_func.h"

extern u_short eeprom[64];

static void
recompute_checksum()
{
	u_short chksum = 0xAAAA;
	unsigned n;

	for (n = 0; n < 63; n++) {
		chksum ^= eeprom[n];
		chksum = (chksum << 1) | (chksum >> 15);
	}
	eeprom[63] = chksum;
}

void
update_eeprom(usbh, newconf)
	usb_dev_handle *usbh;
{
	switch (newconf) {
	case 'C':
		eeprom[2] = 0x7152;
		break;
	case 'S':
		eeprom[2] = 0x6010;
		break;
	default:
		fprintf(stderr, "BUG: wrong argument to update_eeprom()\n");
		abort();
	}
	eeprom[31] = newconf;
	recompute_checksum();
	ftmini_write_eeprom_loc(usbh, 2, eeprom[2]);
	ftmini_write_eeprom_loc(usbh, 31, eeprom[31]);
	ftmini_write_eeprom_loc(usbh, 63, eeprom[63]);
}