fe2fc83936
When CONFIG_VBOOT_VBNV_CMOS_BACKUP_TO_FLASH is set, vbnv_cmos will try to load VBNV from flash if the VBNV in CMOS is invalid. This is usually correct, except the case of battery cut-off. CMOS will always be invalid after battery cut-off if there is no RTC battery (or if that is dead). However, in current implementation the backup in flash is only updated in coreboot, while the real battery cutoff (and the clearing of cutoff flags in VBNV) is done in payload (Depthcharge) stage. This will create an endless reboot loop that: 1. crossystem sets battery cutoff flag in VBNV_CMOS then reboot. 2. coreboot backs-up VBNV_CMOS to VBNV_flash. 3. Depthcharge sees cutoff flag in VBNV_CMOS. 4. Depthcharge clears cutoff flag in VBNV_CMOS. 5. Depthcharge performs battery cutoff (CMOS data is lost). 6. (Plug AC adapter) Reboot. 7. Coreboot sees invalid VBNV_CMOS, load backup from VBNV_flash. 8. Jump to 3. As a result, we should always clear battery cutoff flags when loading backups from VBNV_flash. BRANCH=glados,reef BUG=chrome-os-partner:61365,chrome-os-partner:59615 TEST=emerge-reef coreboot bootimage; Change-Id: I3250a3a179a7b0de9c6e401e4a94dcd23920e473 Signed-off-by: Hung-Te Lin <hungte@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/423460 Reviewed-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: https://review.coreboot.org/18008 Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth <martinroth@google.com>
50 lines
1.7 KiB
C
50 lines
1.7 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2015 The ChromiumOS Authors. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef __VBOOT_VBNV_LAYOUT_H__
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#define __VBOOT_VBNV_LAYOUT_H__
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#define VBOOT_VBNV_BLOCK_SIZE 16 /* Size of NV storage block in bytes */
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/* Constants for NV storage. We use this rather than structs and
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* bitfields so the data format is consistent across platforms and
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* compilers.
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*/
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#define HEADER_OFFSET 0
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#define HEADER_MASK 0xC0
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#define HEADER_SIGNATURE 0x40
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#define HEADER_FIRMWARE_SETTINGS_RESET 0x20
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#define HEADER_KERNEL_SETTINGS_RESET 0x10
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#define BOOT_OFFSET 1
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#define BOOT_DEBUG_RESET_MODE 0x80
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#define BOOT_DISABLE_DEV_REQUEST 0x40
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#define BOOT_OPROM_NEEDED 0x20
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#define BOOT_TRY_B_COUNT_MASK 0x0F
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#define RECOVERY_OFFSET 2
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#define LOCALIZATION_OFFSET 3
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#define DEV_FLAGS_OFFSET 4
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#define DEV_BOOT_USB_MASK 0x01
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#define DEV_BOOT_SIGNED_ONLY_MASK 0x02
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#define MISC_FLAGS_OFFSET 8
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#define MISC_FLAGS_BATTERY_CUTOFF_MASK 0x08
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#define KERNEL_FIELD_OFFSET 11
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#define CRC_OFFSET 15
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#endif /* __VBOOT_VBNV_LAYOUT_H__ */
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