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;
From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@gmail.com>
To:     Andre Przywara <andre.przywara@arm.com>,
        Samuel Holland <samuel@sholland.org>
Cc:     Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Icenowy Zheng <icenowy@aosc.io>,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v11 3/6] arm64: dts: allwinner: Add Allwinner H616 .dtsi file
Date:   Thu, 07 Jul 2022 18:39:47 +0200
Message-ID: <2187076.iZASKD2KPV@jernej-laptop>
In-Reply-To: <39537f95-2ed4-f526-5912-364c1c1ed512@sholland.org>
References: <20220428230933.15262-1-andre.przywara@arm.com> <20220706141655.15d2dd0e@donnerap.cambridge.arm.com> <39537f95-2ed4-f526-5912-364c1c1ed512@sholland.org>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Dne =C4=8Detrtek, 07. julij 2022 ob 08:30:32 CEST je Samuel Holland napisal=
(a):
> Hi Andre, Jernej,
>=20
> On 7/6/22 8:16 AM, Andre Przywara wrote:
> > so after seemingly having finished writing this email, I realised that
> > this won't really help, as I think this diverts the discussion. And the
> > problem has been around for a while, and won't probably be solved easily
> > or quickly. I think we agree to disagree here, or we should admit that
> > there are different approaches ("bundled firmware" vs. "UEFI"), so in t=
he
> > interest of not blocking the H616 series:
> >=20
> > Shall I just keep the firmware node? This would work both ways, whereas
> > dropping the node would impede the "bundled firmware" approach?
>=20
> Let me try to sum up the relevant portion of my thoughts (and save the re=
st
> for elsewhere):
>=20
> The only reason to add the reserved-memory node is to support
> externally-loaded DTBs. By adding the node, we are committing to support
> externally-loaded DTBs on this SoC.
>=20
> Upgrading the kernel is not allowed to break boot. If we support
> externally-loaded DTBs, that rule extends to DTBs shipped with the kernel.
>=20
> If we remove the reserved-memory node, the combination of old U-Boot + new
> externally-loaded DTB will stop booting (the kernel version is irrelevant=
).
> Therefore, if we add the node, we can never remove it, full stop.
>=20
> I will (begrudgingly) accept that, as long as the node matches what TF-A
> actually generates today. That means, please:
>  - Drop the label and update the node name
>  - Reduce the size to 256 KiB, matching (BL31_LIMIT - BL31_BASE)

In the interest of moving things forward, I agree to that.

Best regards,
Jernej