Messages in this thread | | | From | Ulf Hansson <> | Date | Wed, 26 Jul 2023 13:31:19 +0200 | Subject | Re: [PATCH v2 09/11] cpufreq: scmi: Add support to parse domain-id using #power-domain-cells |
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On Fri, 21 Jul 2023 at 13:59, Sudeep Holla <sudeep.holla@arm.com> wrote: > > On Fri, Jul 21, 2023 at 01:52:17PM +0200, Ulf Hansson wrote: > > On Wed, 19 Jul 2023 at 17:24, Sudeep Holla <sudeep.holla@arm.com> wrote: > > > > > > On Thu, Jul 13, 2023 at 04:17:36PM +0200, Ulf Hansson wrote: > > > > The performance domain-id can be described in DT using the power-domains > > > > property or the clock property. The latter is already supported, so let's > > > > add support for the power-domains too. > > > > > > > > > > How is this supposed to work for the CPUs ? The CPU power domains are > > > generally PSCI on most of the platforms and the one using OSI explicitly > > > need to specify the details while ones using PC will not need to. Also they > > > can never be performance domains too. So I am not sure if I am following this > > > correctly. > > > > Your concerns are certainly correct, I completely forgot about this. > > We need to specify what power-domain index belongs to what, by using > > power-domain-names in DT. So a CPU node, that has both psci for power > > and scmi for performance would then typically look like this: > > > > power-domains = <&CPU_PD0>, <&scmi_dvfs 4>; > > power-domain-names = "psci", "scmi"; > > > > I will take care of this in the next version - and thanks a lot for > > pointing this out! > > > Yes something like this will work. Just curious will this impact the idle > paths ? By that I mean will the presence of additional domains add more > work or will they be skipped as early as possible with just one additional > check ?
Unless I misunderstand your concern, I don't think there is any impact on the idle path whatsoever. This should be entirely orthogonal.
The scmi-cpufreq driver should only have to care about the scmi-performance domain, while the cpuidle-psci driver cares only about psci.
Did that make sense?
Kind regards Uffe
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