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* Copyright 2016 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
package android.hardware.boot@1.0;
* The Boot Control HAL is designed to allow for managing sets of redundant
* partitions, called slots, that can be booted from independently. Slots
* are sets of partitions whose names differ only by a given suffix.
* They are identified here by a 0 indexed number and associated with their
* suffix, which is appended to the base name for any particular partition
* to find the one associated with that slot.
* The primary use of this set up is to allow for background updates while
* the device is running, and to provide a fallback in the event that the
* update fails.
interface IBootControl {
* getNumberSlots() returns the number of available slots.
* For instance, a system with a single set of partitions must return
* 1, a system with A/B must return 2, A/B/C -> 3 and so on. A system with
* less than two slots doesn't support background updates, for example if
* running from a virtual machine with only one copy of each partition for the
* purpose of testing.
getNumberSlots() generates (uint32_t numSlots);
* getCurrentSlot() returns the slot number of that the current boot is booted
* from, for example slot number 0 (Slot A). It is assumed that if the current
* slot is A, then the block devices underlying B can be accessed directly
* without any risk of corruption.
* The returned value is always guaranteed to be strictly less than the
* value returned by getNumberSlots. Slots start at 0 and finish at
* getNumberSlots() - 1. The value returned here must match the suffix passed
* from the bootloader, regardless of which slot is active or successful.
getCurrentSlot() generates (Slot slot);
* markBootSuccessful() marks the current slot as having booted successfully.
* Returns whether the command succeeded.
markBootSuccessful() generates (CommandResult error);
* setActiveBootSlot() marks the slot passed in parameter as the active boot
* slot (see getCurrentSlot for an explanation of the "slot" parameter). This
* overrides any previous call to setSlotAsUnbootable.
* Returns whether the command succeeded.
setActiveBootSlot(Slot slot) generates (CommandResult error);
* setSlotAsUnbootable() marks the slot passed in parameter as
* an unbootable. This can be used while updating the contents of the slot's
* partitions, so that the system must not attempt to boot a known bad set up.
* Returns whether the command succeeded.
setSlotAsUnbootable(Slot slot) generates (CommandResult error);
* isSlotBootable() returns if the slot passed in parameter is bootable. Note
* that slots can be made unbootable by both the bootloader and by the OS
* using setSlotAsUnbootable.
* Returns TRUE if the slot is bootable, FALSE if it's not, and INVALID_SLOT
* if slot does not exist.
isSlotBootable(Slot slot) generates (BoolResult bootable);
* isSlotMarkedSucessful() returns if the slot passed in parameter has been
* marked as successful using markBootSuccessful. Note that only the current
* slot can be marked as successful but any slot can be queried.
* Returns TRUE if the slot has been marked as successful, FALSE if it has
* not, and INVALID_SLOT if the slot does not exist.
isSlotMarkedSuccessful(Slot slot) generates (BoolResult successful);
* getSuffix() returns the string suffix used by partitions that correspond to
* the slot number passed in as a parameter. The bootloader must pass the
* suffix of the currently active slot either through a kernel command line
* property at androidboot.slot_suffix, or the device tree at
* /firmware/android/slot_suffix.
* Returns the empty string "" if slot does not match an existing slot.
getSuffix(Slot slot) generates (string slotSuffix);