[U-Boot] [PATCH v2 0/7] android: Implement A/B boot process

[Ruslan Trofymenko]

This patch series adds support for Android A/B boot process [1].
Main steps of A/B boot process are:
  - A/B metadata integrity check
  - looking for the current slot (where the system should be
    booting from)
  - getting the name of the current boot partition (boot_a or boot_b) 
    and loading the corresponding Android boot image
  - getting the name of the current system partition (system_a or 
    system_b) and passing of its full name via kernel command line
    (like 'root=/dev/mmcblk1p11')
  - passing current slot via kernel command line (like
    'androidboot.slot_suffix=_a') and via A/B metadata (e.g. via
    misc partition)
  - A/B metadata processing: setting the boot success flag for
    current slot, handling the retry counter, etc

A/B metadata is organized according to Android reference [2] and stored
on 'misc' partition. On the first A/B boot process, when 'misc'
partition doesn't contain required data, default A/B metadata will be
created and stored in 'misc' partition. In the end of the Android boot,
'update_verifier' and 'update_engine' services are processing the
A/B metadata through the Boot Control HAL. To confirm the boot was
successful using current slot, "boot success" flag must be set on
Android side.

To enable Android A/B support in U-Boot:
  1. Set the following config options:

         CONFIG_ANDROID_AB=y
         CONFIG_CMD_AB_SELECT=y

  2. Change the disk layout so that it has sloted boot partitions.
     E.g. instead of 'boot' and 'system' partitions there should be
     'boot_a', 'boot_b', 'system_a' and 'system_b' partitions.

To be able to actually test this patch series, the A/B features must
be implemented and enabled in Android as well (see [1] for details).

Documentation and corresponding test for A/B boot is present here. The
last patch in this series integrates A/B boot support on AM57xx based
boards (though it's not enabled by default). Future users of A/B boot
feature can use it as a reference.

This series is a part of previous submission [3] by Alex Deymo. It
contains only A/B feature that was stripped out from there with some
modifications for using with "bootm" command preferred in upstream.

Changes in v2:
  * 'android_ab_select' command is renamed to 'ab_select' command and
     moved to separate 'Android support commands' menu
  * For am57xx boards slotted sections (e.g. system_a and system_b) are
    added to the default sections if CONFIG_CMD_AB_SELECT flag is
    defined
  * Returned function error codes are clarified (errno using)
  * Some types constants and files are renamed
  * Assertion condition is clarified in test case
  * 'debug' calls are changed to 'log_debug'
  * The Guide is clarified by the results of changes

[1] https://source.android.com/devices/tech/ota/ab/ab_implement
[2] bootable/recovery/bootloader_message/include/bootloader_message/bootloader_message.h
[3] https://lists.denx.de/pipermail/u-boot/2017-April/285841.html

Ruslan Trofymenko (7):
  cmd: part: Add 'number' sub-command
  disk: part: Extend API to get partition info
  common: Implement A/B metadata
  cmd: Add 'ab_select' command
  test/py: Add base test case for A/B updates
  doc: android: Add simple guide for A/B updates
  env: am57xx: Implement A/B boot process

 cmd/Kconfig                   |  15 +++
 cmd/Makefile                  |   1 +
 cmd/ab_select.c               |  52 ++++++++
 cmd/part.c                    |  16 ++-
 common/Kconfig                |  10 ++
 common/Makefile               |   1 +
 common/android_ab.c           | 277 ++++++++++++++++++++++++++++++++++++++++++
 configs/sandbox_defconfig     |   2 +
 disk/part.c                   |  68 +++++++++++
 doc/README.android-ab         |  67 ++++++++++
 include/android_ab.h          |  34 ++++++
 include/android_bl_msg.h      | 169 ++++++++++++++++++++++++++
 include/environment/ti/boot.h |  58 ++++++++-
 include/part.h                |  21 ++++
 test/py/tests/test_ab.py      |  74 +++++++++++
 15 files changed, 858 insertions(+), 7 deletions(-)
 create mode 100644 cmd/ab_select.c
 create mode 100644 common/android_ab.c
 create mode 100644 doc/README.android-ab
 create mode 100644 include/android_ab.h
 create mode 100644 include/android_bl_msg.h
 create mode 100644 test/py/tests/test_ab.py

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2.7.4