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From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Thu, 15 Sep 2022 23:41:58 +0100
Message-ID: <CA+V-a8tWaKPNmNjJY6sX1yyUz1V5S7JXP+Eenxo4jOtu7uXXLQ@mail.gmail.com>
Subject: Re: [PATCH v3 08/10] riscv: dts: renesas: Add minimal DTS for Renesas
 RZ/Five SMARC EVK
To:     Conor.Dooley@microchip.com
Cc:     geert+renesas@glider.be, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, paul.walmsley@sifive.com,
        palmer@dabbelt.com, aou@eecs.berkeley.edu, heiko@sntech.de,
        atishp@rivosinc.com, devicetree@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org, biju.das.jz@bp.renesas.com,
        prabhakar.mahadev-lad.rj@bp.renesas.com
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Hi Conor,

Thank you for the review.

On Thu, Sep 15, 2022 at 10:56 PM <Conor.Dooley@microchip.com> wrote:
>
> On 15/09/2022 19:15, Prabhakar wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Enable the minimal blocks required for booting the Renesas RZ/Five
> > SMARC EVK with initramfs.
> >
> > Below are the blocks enabled:
> > - CPG
> > - CPU0
> > - DDR (memory regions)
> > - PINCTRL
> > - PLIC
> > - SCIF0
> >
> > Note we have deleted the nodes from the DT for which support needs to be
> > added for RZ/Five SoC and are enabled by RZ/G2UL SMARC EVK SoM/carrier
> > board DTS/I.
>
> idk, I am not sure what to think of this approach.
>
> What do you mean by "for which support needs to be added"? If the support
> does not exist yet, then is surely you can just add the nodes and it will
> be fine?
>
As pointed out previously, I am re-using the below files [1] (SoM) and
[2] (Carrier board) as the RZ/Five SMARC EVK is pin compatible. Since
[1] and [2] enable almost all the peripherals (status = okay)  on the
RZ/G2UL SMARC EVK which are supported. For example [1] enables SDHI0/1
this high speed block needs DMA and without cache management fixed on
Andes core we cannot enable this on RZ/Five SoC so currently a
placeholder is added for it in the RZ/FIve SoC DTSI and is deleted in
the board DTS file.

Below blocks suffer the cache management issue:
- DMAC
- ETH
- SDHI
- USB

Rest of the blocks will be gradually enabled (as soon as this initial
patchset is merged) along with the DT binding doc updates.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi?h=v6.0-rc5
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/renesas/rzg2ul-smarc.dtsi?h=v6.0-rc5

Cheers,
Prabhakar