Re: [PATCH v3 6/7] riscv: dts: starfive: Add initial StarFive JH7110 device tree

From: Conor Dooley <conor@kernel.org>
To: Hal Feng <hal.feng@starfivetech.com>
Cc: linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Ben Dooks <ben.dooks@sifive.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>, Stephen Boyd <sboyd@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Emil Renner Berthing <emil.renner.berthing@canonical.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/7] riscv: dts: starfive: Add initial StarFive JH7110 device tree
Date: Wed, 28 Dec 2022 22:48:43 +0000	[thread overview]
Message-ID: <Y6zHy9oL4xzl+6Rd@spud> (raw)
In-Reply-To: <20221220011247.35560-7-hal.feng@starfivetech.com>

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Hey,

On Tue, Dec 20, 2022 at 09:12:46AM +0800, Hal Feng wrote:
> From: Emil Renner Berthing <kernel@esmil.dk>
> 
> Add initial device tree for the JH7110 RISC-V SoC by StarFive
> Technology Ltd.
> 
> Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
> Co-developed-by: Jianlong Huang <jianlong.huang@starfivetech.com>
> Signed-off-by: Jianlong Huang <jianlong.huang@starfivetech.com>
> Co-developed-by: Hal Feng <hal.feng@starfivetech.com>
> Signed-off-by: Hal Feng <hal.feng@starfivetech.com>
> ---
>  arch/riscv/boot/dts/starfive/jh7110.dtsi | 411 +++++++++++++++++++++++
>  1 file changed, 411 insertions(+)
>  create mode 100644 arch/riscv/boot/dts/starfive/jh7110.dtsi
> 
> diff --git a/arch/riscv/boot/dts/starfive/jh7110.dtsi b/arch/riscv/boot/dts/starfive/jh7110.dtsi
> new file mode 100644
> index 000000000000..64d260ea1f29
> --- /dev/null
> +++ b/arch/riscv/boot/dts/starfive/jh7110.dtsi
> @@ -0,0 +1,411 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +/*
> + * Copyright (C) 2022 StarFive Technology Co., Ltd.
> + * Copyright (C) 2022 Emil Renner Berthing <kernel@esmil.dk>
> + */
> +
> +/dts-v1/;
> +#include <dt-bindings/clock/starfive,jh7110-crg.h>
> +#include <dt-bindings/reset/starfive,jh7110-crg.h>
> +
> +/ {
> +	compatible = "starfive,jh7110";
> +	#address-cells = <2>;
> +	#size-cells = <2>;
> +
> +	cpus {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		S76_0: cpu@0 {
> +			compatible = "sifive,u74-mc", "riscv";

The label here says S76 but the compatible says u74-mc.
Which is correct? Your docs say S7 and S76, so I would imagine that it
is actually an S76?

> +			reg = <0>;
> +			d-cache-block-size = <64>;
> +			d-cache-sets = <64>;
> +			d-cache-size = <8192>;
> +			d-tlb-sets = <1>;
> +			d-tlb-size = <40>;
> +			device_type = "cpu";
> +			i-cache-block-size = <64>;
> +			i-cache-sets = <64>;
> +			i-cache-size = <16384>;
> +			i-tlb-sets = <1>;
> +			i-tlb-size = <40>;
> +			mmu-type = "riscv,sv39";
> +			next-level-cache = <&ccache>;
> +			riscv,isa = "rv64imac";

While I was poking around trying to see if there was some logic behind
that compatible, I noticed that SiFive's docs for the S76 say it is
RV64GBC *but* the docs for the u74-mc say "4xRV64GBC and 1xRV64IMAC".
I assume that rv64imac is the correct one here?

> +			tlb-split;
> +			status = "disabled";
> +
> +			cpu0_intc: interrupt-controller {
> +				compatible = "riscv,cpu-intc";
> +				interrupt-controller;
> +				#interrupt-cells = <1>;
> +			};
> +		};
> +
> +		U74_1: cpu@1 {
> +			compatible = "sifive,u74-mc", "riscv";
> +			reg = <1>;
> +			d-cache-block-size = <64>;
> +			d-cache-sets = <64>;
> +			d-cache-size = <32768>;
> +			d-tlb-sets = <1>;
> +			d-tlb-size = <40>;
> +			device_type = "cpu";
> +			i-cache-block-size = <64>;
> +			i-cache-sets = <64>;
> +			i-cache-size = <32768>;
> +			i-tlb-sets = <1>;
> +			i-tlb-size = <40>;
> +			mmu-type = "riscv,sv39";
> +			next-level-cache = <&ccache>;
> +			riscv,isa = "rv64imafdc";

That also begs the question:
Do your u74s support RV64GBC, as the (current) SiFive documentation
suggests?

Thanks,
Conor.

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