On Mon, Feb 28, 2022 at 11:42 AM Huacai Chen <chenhuacai@xxxxxxxxx> wrote:
> On Mon, Feb 28, 2022 at 4:52 PM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
> > On Mon, 28 Feb 2022 at 09:38, Huacai Chen <chenhuacai@xxxxxxxxx> wrote:
> > > >
> > > > RISC-V is a useful reference for the changes needed - this is the most
> > > > recent addition to the EFI stub, and avoids some legacy stuff that new
> > > > architectures have no need for.
> > > We still want to support the raw elf kernel (RISC-V also does),
> > > because LoongArch also has MCU and SoC and we want to support FDT (I
> > > think this is reasonable, because RISC-V also supports raw elf).
> > >
> >
> > That is fine. So perhaps the best course of action is to omit the
> > UEFI/ACPI parts entirely for now, and focus on the DT/embedded use
> > case. Once all the spec pieces are in place, the UEFI + ACPI changes
> > can be presented as a single coherent set.
> It seems that I made you confusing. :)
> There are big CPUs and small CPUs (MCU and SoC), big CPUs use
> UEFI+ACPI, while small CPUs use FDT.
> At present, the only matured LoongArch CPU is Loongson-3A5000 (big
> CPU) which uses UEFI+ACPI.
> We want to support raw elf because it can run on both ACPI firmware
> and FDT firmware, but at present we only have ACPI firmware.
Can't you just use the UEFI protocol for kernel entry regardless
of the bootloader? It seems odd to use a different protocol for loading
grub and the kernel, especially if that means you end up having to
support both protocols inside of u-boot and grub, in order to chain-load
a uefi application like grub.
Arnd
