Re: [PATCH v4 5/5] arm64: dts: renesas: R8A78000: Add initial Ironhide support

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Morimoto-san,

On Wed, 17 Sept 2025 at 07:31, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
> From: Hai Pham <hai.pham.ud@renesas.com>
>
> Add the initial support for Renesas X5H Ironhide board.
>
> Note: It is using "maxcpus" in bootargs to limit number of CPU, because
> SMP support is now under development. This limitation will be removed
> in the future.
>
> [Kuninori: tidyup for upstreaming]
>
> Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
> Signed-off-by: Vinh Nguyen <vinh.nguyen.xz@renesas.com>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> Signed-off-by: Khanh Le <khanh.le.xr@renesas.com>
> Signed-off-by: Huy Bui <huy.bui.wm@renesas.com>
> Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Thanks for the update!

> --- /dev/null
> +++ b/arch/arm64/boot/dts/renesas/r8a78000-ironhide.dts
> @@ -0,0 +1,92 @@
> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +/*
> + * Device Tree Source for the Ironhide board
> + *
> + * Copyright (C) 2025 Renesas Electronics Corp.
> + */
> +
> +/dts-v1/;
> +#include "r8a78000.dtsi"
> +
> +/ {
> +       model = "Renesas Ironhide board based on r8a78000";
> +       compatible = "renesas,ironhide", "renesas,r8a78000";
> +
> +       aliases {
> +               serial0 = &hscif0;
> +       };
> +
> +       chosen {
> +               /*
> +                * REMOVE-ME
> +                *
> +                * It works 1 CPU core only for now. This limitation will be
> +                * removed in future.
> +                */
> +               bootargs = "maxcpus=1";

I still don't fully understand why this is needed: without that line,
Ironhide boots fine, and only a single CPU is enabled.
None of the cpu node have an enable-method, so Linux does not try to
enable secondary CPUs anyway.  Even with the enable-method re-added
(like in your v2), Linux cannot enable secondary CPUs, as there is no
PSCI node.

What am I missing?

> +               stdout-path = "serial0:1843200n8";
> +       };

The rest LGTM.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds