This driver's purpose is to parse boot modes described in DT, via key
(node name) / value pairs, and to match them to a reboot mode requested
by the kernel. Unfortunately, DT node names can not contain certain
characters, like space ' ' or comma ',' or slash '/', while the
requested reboot mode may.
This is a problem because it makes it impossible to match reboot modes
containing any of those characters.
For example, this makes it impossible to communicate DM verity errors
to the boot loader - DM verity errors trigger a reboot with mode
"dm-verity device corrupted" in drivers/md/dm-verity-target.c and
devices typically have to take action in that case [1]. Changing this
string itself is not feasible, see e.g. discussion in [2], but would
also just cover this one case.
Another example is Android, which may use comma in the reboot mode
string, e.g. as "shutdown,thermal" in [3].
The kernel also shouldn't prescribe what characters are allowed inside
the boot mode string for a user to set. It hasn't done this so far, and
introducing such a restriction would be an interface break and
arbitrarily enforce a random new policy.
Therefore, update this driver to do another round of string matching,
after replacing the common characters mentioned above with dash '-', if
a match hasn't been found without doing said replacement.
This now allows us to have DT entries of e.g.:
mode-dm-verity-device-corrupted = <...>
and so on.
Link: https://cs.android.com/android/kernel/superproject/+/android14-gs-pixel-6.1:private/google-modules/power/reset/exynos-gs101-reboot.c;l=144 [1]
Link: https://lore.kernel.org/all/CAAFS_9FuSb7PZwQ2itUh_H7ZdhvAEiiX7fhxJ4kmmv9JCaHmkA@mail.gmail.com/ [2]
Link: https://cs.android.com/android/platform/superproject/main/+/main:system/core/init/reboot_utils.cpp;drc=79ad1e2e9bf1628c141c8cd2fbb4f3df61a6ba75;l=122 [3]
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://lore.kernel.org/r/20250307-reboot-mode-chars-v1-1-d83ff95da524@linaro.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Closing angle bracket was missing.
Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Based on 1 normalized pattern(s):
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
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move the reboot-mode.h include file into include/linux to allow drivers
outside drivers/power/reset to implement reboot-mode.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Provide managed resource version of reboot_mode_register() and
reboot_mode_unregister() to simplify implementations.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
This driver parses the reboot commands like "reboot bootloader"
and "reboot recovery" to get a boot mode described in the
device tree , then call the write interfae to store the boot
mode in some place like special register or sram, which can
be read by the bootloader after system reboot, then the bootloader
can take different action according to the mode stored.
This is commonly used on Android based devices, in order to
reboot the device into fastboot or recovery mode.
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
