Re: [PATCH 0/3] Fix dt-validate issues on qemu dtbdumps due to dt-bindings

From: Jessica Clarke <jrtc27@jrtc27.com>
To: Conor Dooley <mail@conchuod.ie>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Anup Patel <anup@brainfault.org>,
	Conor Dooley <conor.dooley@microchip.com>,
	Guo Ren <guoren@kernel.org>, Sagar Kadam <sagar.kadam@sifive.com>,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-riscv@lists.infradead.org, qemu-riscv@nongnu.org
Subject: Re: [PATCH 0/3] Fix dt-validate issues on qemu dtbdumps due to dt-bindings
Date: Mon, 8 Aug 2022 22:34:24 +0100	[thread overview]
Message-ID: <YvGBYKZyW0B2/wSr@Jessicas-MacBook-Pro> (raw)
In-Reply-To: <20220805162844.1554247-1-mail@conchuod.ie>

On Fri, Aug 05, 2022 at 05:28:42PM +0100, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> The device trees produced automatically for the virt and spike machines
> fail dt-validate on several grounds. Some of these need to be fixed in
> the linux kernel's dt-bindings, but others are caused by bugs in QEMU.
> 
> Patches been sent that fix the QEMU issues [0], but a couple of them
> need to be fixed in the kernel's dt-bindings. The first patches add
> compatibles for "riscv,{clint,plic}0" which are present in drivers and
> the auto generated QEMU dtbs.

IMO the correct thing is to have QEMU use a qemu,plicX rather than to
weaken the requirement that a non-generic compatible be used. Otherwise
you end up with QEMU using something that's marked as deprecated and
either the warning remains and annoys people still or it becomes too
weak and people ignore it when creating real hardware.

> The final patch adds some new ISA strings
> which needs scruitiny from someone with more knowledge about what ISA
> extension strings should be reported in a dt than I have.

Listing every possible ISA string supported by the Linux kernel really
is not going to scale...

Jess

> Thanks to Rob Herring for reporting these issues [1],
> Conor.
> 
> To reproduce the errors:
> ./build/qemu-system-riscv64 -nographic -machine virt,dumpdtb=qemu.dtb
> dt-validate -p /path/to/linux/kernel/Documentation/devicetree/bindings/processed-schema.json qemu.dtb
> (The processed schema needs to be generated first)
> 
> 0 - https://lore.kernel.org/linux-riscv/20220805155405.1504081-1-mail@conchuod.ie
> 1 - https://lore.kernel.org/linux-riscv/20220803170552.GA2250266-robh@kernel.org/
> 
> Conor Dooley (3):
>   dt-bindings: timer: sifive,clint: add legacy riscv compatible
>   dt-bindings: interrupt-controller: sifive,plic: add legacy riscv
>     compatible
>   dt-bindings: riscv: add new riscv,isa strings for emulators
> 
>  .../sifive,plic-1.0.0.yaml                     |  5 +++++
>  .../devicetree/bindings/riscv/cpus.yaml        |  2 ++
>  .../bindings/timer/sifive,clint.yaml           | 18 ++++++++++++------
>  3 files changed, 19 insertions(+), 6 deletions(-)
> 
> 
> base-commit: 42d670bda02fdba0f3944c92f545984501e5788d
> -- 
> 2.37.1
> 
> 
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