The current implementation is reading the whole partition for boot and
vendor_boot image which can be long following the size of the
partition or the time to read blocks (driver/SoC specific).
For example with mediatek mt8365 EVK board, we have a 64MiB boot
partition and the boot image flashed in this partition is only 42MiB.
It takes ~8-9 secs to read the boot partition.
Instead we can retrieved the boot image and vendor boot image size
with these new functions:
- android_image_get_bootimg_size
- android_image_get_vendor_bootimg_size
Use these information and read only the necessary.
By doing this with mt8365 EVK board, we read boot image in ~5 secs.
Signed-off-by: Julien Masson <jmasson@baylibre.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20241121-bootmeth-android-part-sizes-v1-1-25760bbd0f08@baylibre.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Update android bootmeth to support non-A/B image.
Enable AB support only when ANDROID_AB is enabled.
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Link: https://lore.kernel.org/r/20241126-adnroidv2-v4-2-11636106dc69@baylibre.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
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:
3.a. Get slot (A/B) from BCB
3.b. Run AVB (Android Verified Boot) on boot partitions
3.c. Load boot and vendor_boot partitions
3.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.
[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/
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Julien Masson <jmasson@baylibre.com>
Tested-by: Guillaume La Roque <glaroque@baylibre.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
