Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230426034001.16-1-cuiyunhui@bytedance.com> <CAMj1kXEKh9O-ndk3QFibJMYfMbG7vm-cLN2vVQM5eDsYK84NzQ@mail.gmail.com>
 <CAEEQ3wkJB5CKm33mHXUOPX5makYOHF8By6FYGnNzRkM-Mo72OQ@mail.gmail.com>
 <ZEj33QLZqEeL+/y4@FVFF77S0Q05N> <CAEEQ3wmDBJkfOeKCQfcnuE+1=1K0D2pzu+Sn+zPEWk+RHs0NFQ@mail.gmail.com>
 <CAP6exY+ydbzh1EkWTFejzwaW+PA-ySVO2Qj+CVJ1XbSMce2S9Q@mail.gmail.com>
 <ZEpbTE4gcsf8meXc@FVFF77S0Q05N> <CAMj1kXH5kZJ6ff=PRCRDLCBcw2AkEnRL_L1ABuvu5n71=unvAw@mail.gmail.com>
In-Reply-To: <CAMj1kXH5kZJ6ff=PRCRDLCBcw2AkEnRL_L1ABuvu5n71=unvAw@mail.gmail.com>
From:   =?UTF-8?B?6L+Q6L6J5bSU?= <cuiyunhui@bytedance.com>
Date:   Fri, 28 Apr 2023 11:17:56 +0800
Message-ID: <CAEEQ3w=495snOz3UNBO4dpgyfZs3jQoRKo4QRAXXqR5-0j4SWA@mail.gmail.com>
Subject: Re: [External] Re: [PATCH] firmware: added a firmware information
 passing method FFI
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Mark Rutland <mark.rutland@arm.com>,
        ron minnich <rminnich@gmail.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>, rafael@kernel.org,
        lenb@kernel.org, jdelvare@suse.com, yc.hung@mediatek.com,
        angelogioacchino.delregno@collabora.com,
        allen-kh.cheng@mediatek.com, pierre-louis.bossart@linux.intel.com,
        tinghan.shen@mediatek.com, linux-kernel@vger.kernel.org,
        linux-acpi@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Hi Ard, Mark,

On Thu, Apr 27, 2023 at 8:52=E2=80=AFPM Ard Biesheuvel <ardb@kernel.org> wr=
ote:

> and the only combination we do not support is ACPI without EFI, as
> ACPI on arm64 depends on the EFI memory map.
>
> What this patch seems to be proposing is a combination of all of
> these, i.e., doing a pseudo-EFI direct kernel boot where the EFI
> dependencies of ACPI are being fulfilled by ad-hoc descriptions passed
> in via DT.
>
> I am concerned that this will result in a maintenance burden for Linux
> with very little gain, so I feel we should not go down this road.

Judging from the current kernel, getting acpi smbios, memmap tables is
not just a way to have EFI, right?
smbios:SMBIOS_ENTRY_POINT_SCAN_START
acpi:CONFIG_ACPI_LEGACY_TABLES_LOOKUP
memmap: e820

Our current situation is that coreboot does not support EFI, but supports f=
dt,
but we need to support ACPI,  and riscv does not have a reserved
address segment
like x86 that can be used, so our current solution is to pass acpi and
other tables through fdt.

Based on this, do you have a better suggestion ?

Thanks=EF=BC=8C
Yunhui