diff options
| author | Tom Rini | 2024-07-18 13:52:11 -0600 |
|---|---|---|
| committer | Tom Rini | 2024-07-18 17:03:47 -0600 |
| commit | 459560000736ac7c9c8b04522789c20fb45ff95a (patch) | |
| tree | 1d7b710ed41b3781c7de59b777f51917c710833f /doc/develop | |
| parent | cbfd2c28a007ae7601e5451aa2ad750b0453d518 (diff) | |
| parent | c2a2a06e01651ed814f8fae0c21fc49dc72b5af1 (diff) | |
Merge patch series "bootstd: Add Android support"
Mattijs Korpershoek <mkorpershoek@baylibre.com> says:
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
Diffstat (limited to 'doc/develop')
| -rw-r--r-- | doc/develop/bootstd.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/doc/develop/bootstd.rst b/doc/develop/bootstd.rst index 34631089ae0..bdda90fae3f 100644 --- a/doc/develop/bootstd.rst +++ b/doc/develop/bootstd.rst @@ -95,6 +95,7 @@ bootflows. Note: it is possible to have a bootmeth that uses a partition or a whole device directly, but it is more common to use a filesystem. +For example, the Android bootmeth uses a whole device. Note that some bootmeths are 'global', meaning that they select the bootdev themselves. Examples include VBE and EFI boot manager. In this case, they @@ -277,6 +278,9 @@ script_offset_f script_size_f Size of the script to load, e.g. 0x2000 +vendor_boot_comp_addr_r + Address to which to load the vendor_boot Android image, e.g. 0xe0000000 + Some variables are set by script bootmeth: devtype @@ -418,6 +422,7 @@ Bootmeth drivers are provided for: - EFI boot using bootefi from disk - VBE - EFI boot using boot manager + - Android bootflow (boot image v4) Command interface @@ -786,6 +791,7 @@ To do Some things that need to be done to completely replace the distro-boot scripts: - implement extensions (devicetree overlays with add-on boards) +- implement legacy (boot image v2) android boot flow Other ideas: |