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Date:   Wed, 3 May 2023 07:02:00 -0500
From:   Nishanth Menon <nm@ti.com>
To:     Neha Malcom Francis <n-francis@ti.com>
CC:     <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <vigneshr@ti.com>,
        <kristo@kernel.org>, <u-kumar1@ti.com>
Subject: Re: [PATCH v4 2/3] arm64: dts: ti: k3-j721e: Add ESM support
Message-ID: <20230503120200.4xqylyoiczx43esu@gradation>
References: <20230503093310.85779-1-n-francis@ti.com>
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 <20230503114827.lutd2ebygxczvali@argue>
 <82a39b8e-96ad-faa2-714f-c8c6bfbcc5d6@ti.com>
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On 17:25-20230503, Neha Malcom Francis wrote:
> Hi Nishanth,
> 
> On 03/05/23 17:18, Nishanth Menon wrote:
> > On 15:03-20230503, Neha Malcom Francis wrote:
> > > Add address entry mapping ESM on J721E.
> > > 
> > > Signed-off-by: Neha Malcom Francis <n-francis@ti.com>
> > > ---
> > >   arch/arm64/boot/dts/ti/k3-j721e.dtsi | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/arch/arm64/boot/dts/ti/k3-j721e.dtsi b/arch/arm64/boot/dts/ti/k3-j721e.dtsi
> > > index b912143b6a11..52bcde601eb8 100644
> > > --- a/arch/arm64/boot/dts/ti/k3-j721e.dtsi
> > > +++ b/arch/arm64/boot/dts/ti/k3-j721e.dtsi
> > 
> > Why is'nt esm node introduced here?
> > 
> 
> As it stands esm node is already in
> arch/arm/dts/k3-j721e-r5-common-proc-board.dts in u-boot and since this
> patch is motivated to keep the u-boot and kernel dts in sync, I haven't
> added it here.
> 
> Although... I could add it here similar to j7200 and take action to move to
> the same in u-boot... maybe that is better route.

The core problem we have is that part of the hardware description is in
u-boot and a large part is in kernel. That is wrong. eventually, we will
drop u-boot.dtsi and r5-xyz.dts files.. This cleanup journey is towards
that action.

we want kernel to be the canonical description of the hardware. which
means u-boot or zephyr or something else will eventually just copy the
kernel dts and it has information enough about the hardware to be able
to boot.

each of the dependent ecosystems (u-boot, zephyr etc..) have a little
bit of their own binding extensions (such as binman for u-boot), which
is maintained in their own repos. But, the SoC hardware description,
entirely should be available in kernel device tree.

So, please ensure esm is completely described as well.

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D