diff options
Diffstat (limited to 'src/drivers/elog/boot_count.c')
-rw-r--r-- | src/drivers/elog/boot_count.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/src/drivers/elog/boot_count.c b/src/drivers/elog/boot_count.c new file mode 100644 index 0000000000..9ea828d04d --- /dev/null +++ b/src/drivers/elog/boot_count.c @@ -0,0 +1,122 @@ +/* + * 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. + * + * 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 St, Fifth Floor, Boston, MA, 02110-1301 USA + */ + +#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 CONFIG_USE_OPTION_TABLE +# include "option_table.h" +# define BOOT_COUNT_CMOS_OFFSET (CMOS_VSTART_boot_count_offset >> 3) +#else +# if defined(CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET) +# define BOOT_COUNT_CMOS_OFFSET CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET +# else +# error "Must define CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET" +# endif +#endif + +#define BOOT_COUNT_SIGNATURE 0x4342 /* 'BC' */ + +struct boot_count { + u16 signature; + u32 count; + u16 checksum; +} __attribute__ ((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; +} |