linux-kernel - Re: [PATCH 0/5] RISC-V: RPMI performance service bindings and cpufreq support

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Message-ID: <CABdD5xkq=LbaUo=jDGSF2U2Rb0r13EEJQMfSjxEMsSX0mCDyhQ@mail.gmail.com>
Date: Thu, 8 Jan 2026 10:57:39 +0530
From: Rahul Pathak <rahul@...mations.net>
To: Joshua Yeong <joshua.yeong@...rfivetech.com>
Cc: anup@...infault.org, leyfoon.tan@...rfivetech.com, robh@...nel.org, 
	krzk+dt@...nel.org, conor+dt@...nel.org, pjw@...nel.org, palmer@...belt.com, 
	aou@...s.berkeley.edu, alex@...ti.fr, rafael@...nel.org, 
	viresh.kumar@...aro.org, sboyd@...nel.org, jms@....tenstorrent.com, 
	darshan.prajapati@...fochips.com, charlie@...osinc.com, 
	dfustini@....tenstorrent.com, michal.simek@....com, cyy@...self.name, 
	jassisinghbrar@...il.com, andriy.shevchenko@...ux.intel.com, 
	linux-riscv@...ts.infradead.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 0/5] RISC-V: RPMI performance service bindings and cpufreq support

On Tue, Jan 6, 2026 at 2:51 PM Joshua Yeong
<joshua.yeong@...rfivetech.com> wrote:
>
> This patch series introduces support for the RISC-V RPMI (RISC-V Platform
> Management Interface) performance service, covering both Device Tree bindings
> and a corresponding cpufreq driver.
>
> The first part of the series adds YAML bindings to describe the RPMI performance
> service as provided by platform firmware, as well as the supervisor-level
> controller interface exposed to the operating system. The bindings also document
> how CPU nodes reference performance domains managed by RPMI.
>
> The final patch builds on these definitions by introducing a cpufreq driver that
> leverages the RPMI performance service to manage CPU frequency scaling on RISC-V
> systems. The driver supports RPMI access through SBI-based transport mechanisms
> as well as dedicated supervisor-mode transports.
>
> RPMI specification reference [1] and [2]
>
> Test Environment is as follows:
> https://github.com/yeongjoshua/linux/tree/v6.19-rc4/rpmi-performance
> https://github.com/riscv-software-src/opensbi
> https://github.com/yeongjoshua/qemu/tree/rpmi-dev-upstream
>
> Use '-M virt -M rpmi=true' when running qemu
>
> [1] https://github.com/riscv-non-isa/riscv-sbi-doc/releases
> [2] https://github.com/riscv-non-isa/riscv-rpmi/releases
>
> Joshua Yeong (5):
>   dt-bindings: firmware: Add RPMI performance service message proxy
>     bindings
>   dt-bindings: firmware: Add RPMI performance service bindings
>   dt-bindings: riscv: cpus: document performance-domains property
>   cpufreq: Add cpufreq driver for the RISC-V RPMI performance service
>     group
>   MAINTAINERS: Add RISC-V RPMI performance service group


Hi Joshua,

I have a general question -  RPMI performance service group is
primarily defined for devices but can also be used for CPUs.
Do you plan to add a RPMI devfreq driver too for devices?

Thanks
Rahul