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gc_n64_usb-v3/eeprom.c

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/* wusbmote: Wiimote accessory to USB Adapter
* Copyright (C) 2012-2014 Raphaël Assénat
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* The author may be contacted at raph@raphnet.net
*/
#include <avr/eeprom.h>
#include <util/crc16.h>
#include <stdint.h>
#include <string.h>
#include "eeprom.h"
static uint16_t calc_geeprom_data_crc(void)
{
uint16_t crc = 0x0000;
int i;
/* Update the CRC */
for (i=0; i<EEPROM_USED_SIZE_NOCRC; i++) {
crc = _crc_xmodem_update(crc, ((uint8_t*)&g_eeprom_data)[i]);
}
return crc;
}
void eeprom_commit(void)
{
g_eeprom_data.crc16 = calc_geeprom_data_crc();
/* Sync eeprom content */
eeprom_update_block(&g_eeprom_data, EEPROM_BASE_PTR, EEPROM_USED_SIZE);
}
static char isCrcValid()
{
return g_eeprom_data.crc16 == calc_geeprom_data_crc();
}
// return 1 if eeprom was blank
void eeprom_init(void)
{
eeprom_read_block(&g_eeprom_data, EEPROM_BASE_PTR, EEPROM_USED_SIZE);
/* Detect new or corrupted content. Program default values if required. */
if ((g_eeprom_data.magic != EEPROM_MAGIC) || !isCrcValid())
{
memset(&g_eeprom_data, 0, EEPROM_USED_SIZE);
g_eeprom_data.magic = EEPROM_MAGIC;
// Call application code to set application defaults
eeprom_app_write_defaults();
// Write the now valid content to the EEPROM at once.
eeprom_commit();
}
eeprom_app_ready();
}