1/* SPDX-License-Identifier: BSD-2-Clause */
2/*
3 * Copyright (C) 2017 The Android Open Source Project
4 */
5
6#ifndef __ANDROID_AB_H
7#define __ANDROID_AB_H
8
9struct blk_desc;
10struct disk_partition;
11
12/* Android standard boot slot names are 'a', 'b', 'c', ... */
13#define BOOT_SLOT_NAME(slot_num) ('a' + (slot_num))
14
15/* Number of slots */
16#define NUM_SLOTS 2
17
18/**
19 * Select the slot where to boot from.
20 *
21 * On Android devices with more than one boot slot (multiple copies of the
22 * kernel and system images) selects which slot should be used to boot from and
23 * registers the boot attempt. This is used in by the new A/B update model where
24 * one slot is updated in the background while running from the other slot. If
25 * the selected slot did not successfully boot in the past, a boot attempt is
26 * registered before returning from this function so it isn't selected
27 * indefinitely.
28 *
29 * @param[in] dev_desc Place to store the device description pointer
30 * @param[in] part_info Place to store the partition information
31 * Return: The slot number (>= 0) on success, or a negative on error
32 */
33int ab_select_slot(struct blk_desc *dev_desc, struct disk_partition *part_info,
34                   bool dec_tries);
35
36#endif /* __ANDROID_AB_H */
37