linux-kernel - Re: [PATCH v7 06/10] soc: qcom: rpmhpd: Add RPMh power domain driver

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Date:   Wed, 12 Dec 2018 10:25:03 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Rajendra Nayak <rnayak@...eaurora.org>, andy.gross@...aro.org,
        collinsd@...eaurora.org, mka@...omium.org, robh@...nel.org,
        ulf.hansson@...aro.org, viresh.kumar@...aro.org
Cc:     devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Rajendra Nayak <rnayak@...eaurora.org>
Subject: Re: [PATCH v7 06/10] soc: qcom: rpmhpd: Add RPMh power domain driver

Quoting Rajendra Nayak (2018-12-12 01:21:27)
> The RPMh power domain driver aggregates the corner votes from various
> consumers for the ARC resources and communicates it to RPMh.
> 
> With RPMh we use 2 different numbering space for corners, one used
> by the clients to express their performance needs, and another used
> to communicate to RPMh hardware.
> 
> The clients express their performance requirements using a sparse
> numbering space which are mapped to meaningful levels like RET, SVS,
> NOMINAL, TURBO etc which then get mapped to another number space
> between 0 and 15 which is communicated to RPMh. The sparse number space,
> also referred to as vlvl is mapped to the continuous number space of 0
> to 15, also referred to as hlvl, using command DB.
> 
> Some power domain clients could request a performance state only while
> the CPU is active, while some others could request for a certain
> performance state all the time regardless of the state of the CPU.
> We handle this by internally aggregating the votes from both type of
> clients and then send the aggregated votes to RPMh.
> 
> There are also 3 different types of votes that are comunicated to RPMh
> for every resource.
> 1. ACTIVE_ONLY:
>         This specifies the requirement for the resource when the CPU is
>         active
> 2. SLEEP:
>         This specifies the requirement for the resource when the CPU is
>         going to sleep
> 3. WAKE_ONLY:
>         This specifies the requirement for the resource when the CPU is
>         coming out of sleep to active state
> 
> We add data for all power domains on sdm845 SoC as part of the patch.
> The driver can be extended to support other SoCs which support RPMh
> 
> Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
> Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@...omium.org>