android_ab.h 1.1 KB

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