[PATCH 3/3] efi_loader: disk: add EFI_PARTITION_INFO_PROTOCOL support

[Javier Martinez Canillas]

Heinrich Schuchardt <xypron.glpk at gmx.de> writes:

Hello Heinrich,

Thanks for your feedback.

> Am 13. Juni 2025 10:57:38 MESZ schrieb Javier Martinez Canillas <javierm at redhat.com>:
>>The UEFI 2.10 specification mentions that this protocol shall be installed
>>along with EFI_BLOCK_IO_PROTOCOL. It provides cached partition information
>>for MBR and GPT partition types.
>
> U-Boot is targeting the EBBR specifcation which defines a subset of UEFI.
>

Interesting. I knew that the u-boot EFI implementation was to support
SystemReady IR (what is now called SystemReady DeviceTree) and EBBR,
but I didn't know that meant to only implement what's required by EBBR.

I noticed that EFI_PARTITION_INFO_PROTOCOL is not even required by SBBR
and only EFI_BLOCK_IO_PROTOCOL is required there just like for EBBR.

> Which application needs this protocol?

We are experimenting with a new A/B boot protocol and an EFI binary that
implements it. It's inspired on what the Android Boot Loader does for its
A/B booting too.

The project is https://gitlab.com/CentOS/automotive/src/ukiboot and reads
UKI (https://uapi-group.org/specifications/specs/unified_kernel_image)
images from raw data partitions. Just like ABL reads Android Boot images.

> Are you planning to add it to the EBBR specification?
>

I haven't thought about it before but I also didn't know that u-boot had
this requirement. Probably it should be documented somewhere to make it
more clear? Maybe I didn't look enough but didn't find a doc in the repo.

> Best regards 
>
> Heinrich 
>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat