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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2012 The ChromiumOS Authors. All rights reserved.
*
* 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; version 2 of the License.
*
* 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.
*/
#include <console/console.h>
#include <ip_checksum.h>
#include <pc80/mc146818rtc.h>
#include <stddef.h>
#include <stdint.h>
#include <elog.h>
/*
* We need a region in CMOS to store the boot counter.
*
* This can either be declared as part of the option
* table or statically defined in the board config.
*/
#if IS_ENABLED(CONFIG_USE_OPTION_TABLE)
# include "option_table.h"
# define BOOT_COUNT_CMOS_OFFSET (CMOS_VSTART_boot_count_offset >> 3)
#else
# if (CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET != 0)
# define BOOT_COUNT_CMOS_OFFSET CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET
# else
# error "Must configure CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET"
# endif
#endif
#define BOOT_COUNT_SIGNATURE 0x4342 /* 'BC' */
struct boot_count {
u16 signature;
u32 count;
u16 checksum;
} __packed;
/* Read and validate boot count structure from CMOS */
static int boot_count_cmos_read(struct boot_count *bc)
{
u8 i, *p;
u16 csum;
for (p = (u8*)bc, i = 0; i < sizeof(*bc); i++, p++)
*p = cmos_read(BOOT_COUNT_CMOS_OFFSET + i);
/* Verify signature */
if (bc->signature != BOOT_COUNT_SIGNATURE) {
printk(BIOS_DEBUG, "Boot Count invalid signature\n");
return -1;
}
/* Verify checksum over signature and counter only */
csum = compute_ip_checksum(bc, offsetof(struct boot_count, checksum));
if (csum != bc->checksum) {
printk(BIOS_DEBUG, "Boot Count checksum mismatch\n");
return -1;
}
return 0;
}
/* Write boot count structure to CMOS */
static void boot_count_cmos_write(struct boot_count *bc)
{
u8 i, *p;
/* Checksum over signature and counter only */
bc->checksum = compute_ip_checksum(
bc, offsetof(struct boot_count, checksum));
for (p = (u8*)bc, i = 0; i < sizeof(*bc); i++, p++)
cmos_write(*p, BOOT_COUNT_CMOS_OFFSET + i);
}
/* Increment boot count and return the new value */
u32 boot_count_increment(void)
{
struct boot_count bc;
/* Read and increment boot count */
if (boot_count_cmos_read(&bc) < 0) {
/* Structure invalid, re-initialize */
bc.signature = BOOT_COUNT_SIGNATURE;
bc.count = 0;
}
/* Increment boot counter */
bc.count++;
/* Write the new count to CMOS */
boot_count_cmos_write(&bc);
printk(BIOS_DEBUG, "Boot Count incremented to %u\n", bc.count);
return bc.count;
}
/* Return the current boot count */
u32 boot_count_read(void)
{
struct boot_count bc;
if (boot_count_cmos_read(&bc) < 0)
return 0;
return bc.count;
}
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