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Date:   Tue, 22 Mar 2022 18:32:22 -0700 (PDT)
Subject:     Re: [RFC PATCH V2 0/1] RISCV_EFI_BOOT_PROTOCOL support in linux
In-Reply-To: <20220303145944.307321-1-sunilvl@ventanamicro.com>
CC:     ardb@kernel.org, Paul Walmsley <paul.walmsley@sifive.com>,
        aou@eecs.berkeley.edu, heinrich.schuchardt@canonical.com,
        Atish Patra <atishp@rivosinc.com>, apatel@ventanamicro.com,
        abner.chang@hpe.com, jrtc27@jrtc27.com, linux-efi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        sunilvl@ventanamicro.com
From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     sunilvl@ventanamicro.com
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On Thu, 03 Mar 2022 06:59:43 PST (-0800), sunilvl@ventanamicro.com wrote:
> This patch adds support for getting the boot hart ID using new
> RISCV_EFI_BOOT_PROTOCOL in linux efi stub. While there is an existing
> solution of passing the boot hart ID through Device Tree, it doesn't work
> for ACPI. Hence an EFI protocol protocol is recommended which works for
> both DT and ACPI based platforms.
>
> The latest draft spec of this new protocol is available at
> https://github.com/riscv-non-isa/riscv-uefi/releases/download/1.0-rc2/RISCV_UEFI_PROTOCOL-spec.pdf

This looks fine to me, but we need the spec folk to commit to this being 
a stable interface before we can start using it.  Historically that's 
been "frozen" for RISC-V specs, but I'm not sure how that all fits 
together in EFI land as IIUC we also have to follow the UEFI forum's 
process.  Last I checked you guys understood that better than I did, so

Acked-by: Palmer Dabbelt <palmer@rivosinc.com> # pending spec freeze

I had a minor comment about the error message, as well.

Thanks!

> This linux ptach can be found in:
> riscv_boot_protocol_rfc_v2 branch at
> https://github.com/vlsunil/linux.git
>
> This is tested in qemu with u-boot 2022.04.rc3.
>
> Changes since V1:
>   - Rebased to get the "Fix get_boot_hartid_from_fdt() return value"
>     patch
>   - Removed mixed_mode member
>   - Separated return value and status.
>
> Sunil V L (1):
>   riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL
>
>  drivers/firmware/efi/libstub/efistub.h    |  7 ++++++
>  drivers/firmware/efi/libstub/riscv-stub.c | 29 +++++++++++++++++++----
>  include/linux/efi.h                       |  1 +
>  3 files changed, 32 insertions(+), 5 deletions(-)