Porting U-Boot's UEFI Payload to coreboot

Simon Glass sjg at chromium.org
Tue Mar 8 17:09:27 CET 2022


On Tue, 8 Mar 2022 at 06:57, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> On 3/8/22 13:59, Ahamed Husni wrote:
> > Hi everyone,
> >
> > I am trying to work on a project to port the U-Boot UEFI code to coreboot
> > as a payload.
> > I haven't worked with UEFI before except running a basic EFI payload in a
> > coreboot/u-boot environment. (Serial output:
> > https://gist.github.com/drac98/6166d29f6c3a2baf2f4e791925ea98d3)
> >
> > I would like to know how UEFI is implemented in U-Boot. Is UEFI integrated
> > into u-boot or is it implemented like a payload?
> Hello Ahamed,
> the UEFI API implementation is an integral part of U-Boot.
> >
> > Where is the UEFI source code? Is it the following files in the tree
> > https://source.denx.de/u-boot/custodians/u-boot-efi
> > lib/
> > |__ efi/
> > |__ efi_driver/
> > |__ efi_loader/
> U-Boot can both be run on top of UEFI. This is the code you find in
> /lib/efi/. Furthermore UEFI can run as a firmware providing the UEFI
> API. This is what you find in /lib/efi_loader/ and /lib/efi_driver/.
> You can build U-Boot as payload for coreboot which offers the UEFI API
> implementation. See configs/coreboot64_defconfig.
> U-Boot runs ARM and RISC-V Linux successfully via UEFI.
> What architecture are you looking at?
> Simon (on CC) has been working on U-Boot on UEFI and Coreboot while I
> have concentrated on the UEFI API implementation in U-Boot.

Yes you can use U-Boot as a coreboot payload - this is now running in
CI so we make sure it works on each release. I plan to add more test
cases to it but have been waiting to see if coreboot can add something
similar to its CI.

+Stefan Reinauer as we have been talking about this

It seems better to go that way than trying to duplicate efforts. We
have a program now to move UEFI to use driver model properly, for


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