Re: [PATCH v2 0/5] bootstd: Add Android support

[Mattijs Korpershoek <mkorpershoek@baylibre.com>]

Hi Simon,

On lun., juin 17, 2024 at 07:53, Simon Glass <sjg@chromium.org> wrote:

> Hi Mattijs,
>
> On Thu, 13 Jun 2024 at 04:13, Mattijs Korpershoek
> <mkorpershoek@baylibre.com> wrote:
>>
>> Android boot flow is a bit different than a regular Linux distro.
>> Android relies on multiple partitions in order to boot.
>>
>> A typical boot flow would be:
>> 1. Parse the Bootloader Control Block (BCB, misc partition)
>> 2. If BCB requested bootonce-bootloader, start fastboot and wait.
>> 3. If BCB requested recovery or normal android, run the following:
>>    a. Get slot (A/B) from BCB
>>    b. Run AVB (Android Verified Boot) on boot partitions
>>    c. Load boot and vendor_boot partitions
>>    d. Load device-tree, ramdisk and boot
>>
>> The AOSP documentation has more details at [1], [2], [3]
>>
>> This has been implemented via complex boot scripts such as [4].
>> However, these boot script are neither very maintainable nor generic.
>> Moreover, DISTRO_DEFAULTS is being deprecated [5].
>>
>> Add a generic Android bootflow implementation for bootstd.
>>
>> For this initial version, only boot image v4 is supported.
>>
>> This has been tested on sandbox using:
>> $ ./test/py/test.py --bd sandbox --build -k test_ut
>>
>> This has also been tested on the AM62X SK EVM using TI's Android SDK[6]
>> To test on TI board, the following (WIP) patch is needed as well:
>> https://gitlab.baylibre.com/baylibre/ti/ti-u-boot/-/commit/84cceb912bccd7cdd7f9dd69bca0e5d987a1fd04
>>
>> [1] https://source.android.com/docs/core/architecture/bootloader
>> [2] https://source.android.com/docs/core/architecture/partitions
>> [3] https://source.android.com/docs/core/architecture/partitions/generic-boot
>> [4] https://source.denx.de/u-boot/u-boot/-/blob/master/include/configs/meson64_android.h
>> [5] https://lore.kernel.org/r/all/20230914165615.1058529-17-sjg@chromium.org/
>> [6] https://software-dl.ti.com/processor-sdk-android/esd/AM62X/09_02_00/docs/android/Overview.html
>>
>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
>> ---
>> Changes in v2:
>> - Dropped patch 2/6 boot: android: Add image_android_get_version() (Igor)
>> - Fixed multi-line comment style (Igor, Simon)
>> - Added dependency on CMD_FASTBOOT for BOOTMETH_ANDROID (Igor)
>> - Fixed various resource leaks (Igor)
>> - Fixed bootmeth_priv dangling pointer on error cases (Igor)
>> - Updated test instructions in commit message for patch 6/6
>> - Added __weak impl of get_avendor_bootimg_addr() in patch 1 (dropped
>>   Igor's review because of this change)
>> - Added extra info in Kconfig to detail MMC limitation (Simon)
>> - Fixed typo Bootmethod->Bootmeth (Simon)
>> - Documented android_priv structure (Simon)
>> - Demoted various messages from printf() to log_debug (Simon)
>> - Fixed some lines too long (Simon)
>> - Added function documentation to read_slotted_partition() (Simon)
>> - Added some doc about avb extra_args being modified (Simon)
>> - Link to v1: https://lore.kernel.org/r/20240606-bootmeth-android-v1-0-0c69d4457cc5@baylibre.com
>>
>> ---
>> Mattijs Korpershoek (5):
>>       boot: android: Provide vendor_bootimg_addr in boot_get_fdt()
>>       bootstd: Add bootflow_iter_check_mmc() helper
>>       android: boot: Add set_abootimg_addr() and set_avendor_bootimg_addr()
>>       bootstd: Add a bootmeth for Android
>>       bootstd: Add test for bootmeth_android
>>
>>  MAINTAINERS               |   7 +
>>  arch/sandbox/dts/test.dts |   8 +
>>  boot/Kconfig              |  16 ++
>>  boot/Makefile             |   2 +
>>  boot/bootflow.c           |  12 +
>>  boot/bootmeth_android.c   | 553 ++++++++++++++++++++++++++++++++++++++++++++++
>>  boot/bootmeth_android.h   |  29 +++
>>  boot/image-android.c      |   5 +
>>  boot/image-fdt.c          |   2 +-
>>  cmd/abootimg.c            |  10 +
>>  configs/sandbox_defconfig |   2 +-
>>  doc/develop/bootstd.rst   |   6 +
>>  include/bootflow.h        |   9 +
>>  include/image.h           |  14 ++
>>  test/boot/bootflow.c      |  65 +++++-
>>  test/py/tests/test_ut.py  |  76 +++++++
>>  16 files changed, 811 insertions(+), 5 deletions(-)
>> ---
>> base-commit: f9886bc60f42d5bcfcfa4e474af7dc230400b6be
>> change-id: 20240605-bootmeth-android-bfc8596e9367
>>
>> Best regards,
>> --
>> Mattijs Korpershoek <mkorpershoek@baylibre.com>
>>
>
> Thinking about this, I believe we should start having docs about the
> individual bootmeths themselves.

Yes.

>
> Can you add a section about your new bootmeth? I will come up with a
> patch for the others that I know about. Perhaps
> doc/develop/bootstd.rst would be a suitable place for now?

Yes I can add a section. I would have preferred to have an example to
work from there, but I can start writing docs as well.

I'm leaving on vacation soon (without computer), so I'll be able to
send a v3 with docs included in at earliest a 2-3 weeks from now.

If you make a patch for the other bootmeths in the mean-time, please cc
me so that I can help review and have an example for Android.

Thanks!
Mattijs

>
> Regards,
> Simon