1 /* 2 * Copyright 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.hardware.boot@1.0; 18 19 /** 20 * The Boot Control HAL is designed to allow for managing sets of redundant 21 * partitions, called slots, that can be booted from independently. Slots 22 * are sets of partitions whose names differ only by a given suffix. 23 * They are identified here by a 0 indexed number and associated with their 24 * suffix, which is appended to the base name for any particular partition 25 * to find the one associated with that slot. 26 * The primary use of this set up is to allow for background updates while 27 * the device is running, and to provide a fallback in the event that the 28 * update fails. 29 */ 30 interface IBootControl { 31 /** 32 * getNumberSlots() returns the number of available slots. 33 * For instance, a system with a single set of partitions must return 34 * 1, a system with A/B must return 2, A/B/C -> 3 and so on. A system with 35 * less than two slots doesn't support background updates, for example if 36 * running from a virtual machine with only one copy of each partition for the 37 * purpose of testing. 38 */ 39 getNumberSlots() generates (uint32_t numSlots); 40 41 /** 42 * getCurrentSlot() returns the slot number of that the current boot is booted 43 * from, for example slot number 0 (Slot A). It is assumed that if the current 44 * slot is A, then the block devices underlying B can be accessed directly 45 * without any risk of corruption. 46 * The returned value is always guaranteed to be strictly less than the 47 * value returned by getNumberSlots. Slots start at 0 and finish at 48 * getNumberSlots() - 1. The value returned here must match the suffix passed 49 * from the bootloader, regardless of which slot is active or successful. 50 */ 51 getCurrentSlot() generates (Slot slot); 52 53 /** 54 * markBootSuccessful() marks the current slot as having booted successfully. 55 * 56 * Returns whether the command succeeded. 57 */ 58 markBootSuccessful() generates (CommandResult error); 59 60 /** 61 * setActiveBootSlot() marks the slot passed in parameter as the active boot 62 * slot (see getCurrentSlot for an explanation of the "slot" parameter). This 63 * overrides any previous call to setSlotAsUnbootable. 64 * Returns whether the command succeeded. 65 */ 66 setActiveBootSlot(Slot slot) generates (CommandResult error); 67 68 /** 69 * setSlotAsUnbootable() marks the slot passed in parameter as 70 * an unbootable. This can be used while updating the contents of the slot's 71 * partitions, so that the system must not attempt to boot a known bad set up. 72 * Returns whether the command succeeded. 73 */ 74 setSlotAsUnbootable(Slot slot) generates (CommandResult error); 75 76 /** 77 * isSlotBootable() returns if the slot passed in parameter is bootable. Note 78 * that slots can be made unbootable by both the bootloader and by the OS 79 * using setSlotAsUnbootable. 80 * Returns TRUE if the slot is bootable, FALSE if it's not, and INVALID_SLOT 81 * if slot does not exist. 82 */ 83 isSlotBootable(Slot slot) generates (BoolResult bootable); 84 85 /** 86 * isSlotMarkedSucessful() returns if the slot passed in parameter has been 87 * marked as successful using markBootSuccessful. Note that only the current 88 * slot can be marked as successful but any slot can be queried. 89 * Returns TRUE if the slot has been marked as successful, FALSE if it has 90 * not, and INVALID_SLOT if the slot does not exist. 91 */ 92 isSlotMarkedSuccessful(Slot slot) generates (BoolResult successful); 93 94 /** 95 * getSuffix() returns the string suffix used by partitions that correspond to 96 * the slot number passed in as a parameter. The bootloader must pass the 97 * suffix of the currently active slot either through a kernel command line 98 * property at androidboot.slot_suffix, or the device tree at 99 * /firmware/android/slot_suffix. 100 * Returns the empty string "" if slot does not match an existing slot. 101 */ 102 getSuffix(Slot slot) generates (string slotSuffix); 103 }; 104 105
