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Date: Thu, 15 Feb 2024 11:26:26 +0000
From: Sudeep Holla <sudeep.holla@arm.com>
To: Saravana Kannan <saravanak@google.com>, David Dai <davidai@google.com>
Cc: Rob Herring <robh@kernel.org>, "Rafael J. Wysocki" <rafael@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Quentin Perret <qperret@google.com>,
	Masami Hiramatsu <mhiramat@google.com>,
	Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Pavan Kondeti <quic_pkondeti@quicinc.com>,
	Gupta Pankaj <pankaj.gupta@amd.com>, Mel Gorman <mgorman@suse.de>,
	kernel-team@android.com, linux-pm@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 1/2] dt-bindings: cpufreq: add virtual cpufreq device
Message-ID: <20240215112626.zfkiq2i2imbqcdof@bogus>
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 <20240131170608.GA1441369-robh@kernel.org>
 <CAGETcx8S0oS67oMZsPKk6_MGAtygoHEf_LN1gbcNDEBqRJ4PPg@mail.gmail.com>
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On Fri, Feb 02, 2024 at 09:53:52AM -0600, Rob Herring wrote:
> On Wed, Jan 31, 2024 at 10:23:03AM -0800, Saravana Kannan wrote:
> >
> > We also need the OPP tables to indicate which CPUs are part of the
> > same cluster, etc. Don't want to invent a new "protocol" and just use
> > existing DT bindings.
> 
> Topology binding is for that.
> 
> What about when x86 and other ACPI systems need to do this too? You 
> define a discoverable interface, then it works regardless of firmware. 
> KVM, Virtio, VFIO, etc. are all their own protocols.
>

+1 for the above. I have mentioned the same couple of times but I am told
it can be taken up later which I fail to understand. Once we define DT
bindings, it must be supported for long time which doesn't provide any
motivation to such a discoverable interface which works on any virtual
platforms irrespective of the firmware.

--
Regards,
Sudeep