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References: <20230925131715.138411-1-ulf.hansson@linaro.org> <20230925131715.138411-7-ulf.hansson@linaro.org>
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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Mon, 25 Sep 2023 15:33:49 +0200
Message-ID: <CAPDyKFo+XCEtTSNqtA1SeajWo4tuRroA4GrRegta5TsqSGd4eQ@mail.gmail.com>
Subject: Re: [PATCH 6/9] OPP: Extend support for the opp-level beyond required-opps
To:     Sudeep Holla <sudeep.holla@arm.com>,
        Cristian Marussi <cristian.marussi@arm.com>,
        Viresh Kumar <vireshk@kernel.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>
Cc:     Nishanth Menon <nm@ti.com>, Stephen Boyd <sboyd@kernel.org>,
        Nikunj Kela <nkela@quicinc.com>,
        Prasad Sodagudi <psodagud@quicinc.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
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Precedence: bulk

On Mon, 25 Sept 2023 at 15:18, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> At this point the level (performance state) for an OPP is currently limited
> to be requested for a device that is attached to a PM domain.  Moreover,
> the device needs to have the so called required-opps assigned to it, which
> are based upon OPP tables being described in DT.
>
> To extend the support beyond required-opps and DT, let's enable the level
> to be set for all OPPs. More precisely, if the requested OPP has a valid
> level let's try to request it through the device's optional PM domain, via
> calling dev_pm_domain_set_performance_state().
>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/opp/core.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
>
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index 60dca60ac4af..afb73978cdcb 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -1107,6 +1107,22 @@ void _update_set_required_opps(struct opp_table *opp_table)
>                 opp_table->set_required_opps = _opp_set_required_opps_generic;
>  }
>
> +static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
> +                         struct dev_pm_opp *opp)
> +{
> +       int ret = 0;
> +
> +       /* Request a new performance state through the device's PM domain. */
> +       if (opp && opp->level) {
> +               ret = dev_pm_domain_set_performance_state(dev, opp->level);
> +               if (ret)
> +                       dev_err(dev, "Failed to set performance state %u (%d)\n",
> +                               opp->level, ret);
> +       }

Okay, so reviewing my own code found a problem here. We need an "else"
here, that should request the performance state to be set to 0.

I am not sending a new version at this point, but awaiting more feedback first.

> +
> +       return ret;
> +}
> +
>  static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
>  {
>         struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
> @@ -1154,8 +1170,13 @@ static int _disable_opp_table(struct device *dev, struct opp_table *opp_table)
>         if (opp_table->regulators)
>                 regulator_disable(opp_table->regulators[0]);
>
> +       ret = _set_opp_level(dev, opp_table, NULL);
> +       if (ret)
> +               goto out;
> +
>         ret = _set_required_opps(dev, opp_table, NULL, false);
>
> +out:
>         opp_table->enabled = false;
>         return ret;
>  }
> @@ -1198,6 +1219,10 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
>                         return ret;
>                 }
>
> +               ret = _set_opp_level(dev, opp_table, opp);
> +               if (ret)
> +                       return ret;
> +
>                 ret = _set_opp_bw(opp_table, opp, dev);
>                 if (ret) {
>                         dev_err(dev, "Failed to set bw: %d\n", ret);
> @@ -1241,6 +1266,10 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
>                         return ret;
>                 }
>
> +               ret = _set_opp_level(dev, opp_table, opp);
> +               if (ret)
> +                       return ret;
> +
>                 ret = _set_required_opps(dev, opp_table, opp, false);
>                 if (ret) {
>                         dev_err(dev, "Failed to set required opps: %d\n", ret);
> --
> 2.34.1
>

Kind regards
Uffe