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From: Qingfang Deng <dqfext@gmail.com>
Date: Mon, 11 Mar 2024 15:56:29 +0800
Message-ID: <CALW65jZ+q8sDiRKgsRL9n+939HNUCnkKuO=YJjHB5Js=WYQeOg@mail.gmail.com>
Subject: Re: [PATCH] perf: RISC-V: fix IRQ detection on T-Head C908
To: Inochi Amaoto <inochiama@outlook.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, 
	Albert Ou <aou@eecs.berkeley.edu>, Atish Patra <atishp@atishpatra.org>, 
	Anup Patel <anup@brainfault.org>, Will Deacon <will@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, Andrew Jones <ajones@ventanamicro.com>, 
	Conor Dooley <conor.dooley@microchip.com>, Heiko Stuebner <heiko@sntech.de>, 
	Guo Ren <guoren@kernel.org>, linux-riscv@lists.infradead.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
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Hi Inochi,

On Mon, Mar 11, 2024 at 3:13=E2=80=AFPM Inochi Amaoto <inochiama@outlook.co=
m> wrote:
>
> On Mon, Mar 11, 2024 at 02:30:18PM +0800, Qingfang Deng wrote:
> > T-Head C908 has the same IRQ num and CSR as previous C9xx cores, but
> > reports non-zero marchid and mimpid. Remove the ID checks.
> >
>
> Hi, Qingfang,
>
> IIRC, the existed C908 SoC (such as K230) have an early version
> of C908 core. But C908 core itself may support Sscofpmf.
> So I do not think removing the ID checks is a good idea. Instead,
> I suggest adding CPUID of your SoC to this check.

As of Feb 2024, the latest C908 revision does not support Sscofpmf.
You may Google "C908R1S0" to see its user manual.
But I think you're right. Even though C908 does not have Sscofpmf,
T-Head may release new SoCs which do have Sscofpmf, and the check will
break. I will submit a new patch with your suggested changes.

Regards,
Qingfang
>
> Regards,
> Inochi
>