linux-kernel - Re: [RFC RESEND PATCH 3/7] soc: mediatek: add support for the performance state

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Message-ID: <154655622671.15366.9695869469694306752@swboyd.mtv.corp.google.com>
Date:   Thu, 03 Jan 2019 14:57:06 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     Henry Chen <henryc.chen@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>
Cc:     Mark Rutland <mark.rutland@....com>,
        Fan Chen <fan.chen@...iatek.com>,
        Weiyi Lu <weiyi.lu@...iatek.com>,
        James Liao <jamesjj.liao@...iatek.com>,
        Kees Cook <keescook@...omium.org>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Henry Chen <henryc.chen@...iatek.com>
Subject: Re: [RFC RESEND PATCH 3/7] soc: mediatek: add support for the performance state

Quoting Henry Chen (2019-01-02 06:09:54)
> @@ -187,6 +190,18 @@ struct scp_soc_data {
>         bool bus_prot_reg_update;
>  };
>  
> +BLOCKING_NOTIFIER_HEAD(scpsys_notifier_list);

static?

> +
> +int register_scpsys_notifier(struct notifier_block *nb)
> +{
> +       return blocking_notifier_chain_register(&scpsys_notifier_list, nb);
> +}
> +
> +int unregister_scpsys_notifier(struct notifier_block *nb)
> +{
> +       return blocking_notifier_chain_unregister(&scpsys_notifier_list, nb);
> +}

What is the notifier for?

> +
>  static int scpsys_domain_is_on(struct scp_domain *scpd)
>  {
>         struct scp *scp = scpd->scp;
> @@ -536,6 +551,48 @@ static void init_clks(struct platform_device *pdev, struct clk **clk)
>                 clk[i] = devm_clk_get(&pdev->dev, clk_names[i]);
>  }
>  
> +static int mtk_pd_set_performance(struct generic_pm_domain *genpd,
> +                                 unsigned int state)
> +{
> +       int i;
> +       struct scp_domain *scpd =
> +               container_of(genpd, struct scp_domain, genpd);
> +       struct scp_event_data scpe;
> +       struct scp *scp = scpd->scp;
> +       struct genpd_onecell_data *pd_data = &scp->pd_data;
> +
> +       for (i = 0; i < pd_data->num_domains; i++) {
> +               if (genpd == pd_data->domains[i]) {
> +                       dev_dbg(scp->dev, "%d. %s = %d\n",
> +                               i, genpd->name, state);
> +                       break;
> +               }
> +       }
> +
> +       scpe.event_type = MTK_SCPSYS_PSTATE;
> +       scpe.genpd = genpd;
> +       scpe.domain_id = i;
> +       blocking_notifier_call_chain(&scpsys_notifier_list, state, &scpe);
> +
> +       return 0;
> +}
> +
> +static unsigned int mtk_pd_get_performance(struct generic_pm_domain *genpd,
> +                                          struct dev_pm_opp *opp)
> +{
> +       struct device_node *np;
> +       unsigned int state;
> +
> +       np = dev_pm_opp_get_of_node(opp);
> +
> +       if (of_property_read_u32(np, "mtk,level", &state))
> +               return 0;
> +
> +       of_node_put(np);

The generic API that Rajendra is adding I guess will become even more
generic by assuming some sort of property like 'opp-level' or
'performance-state' that is just some raw number.

> +
> +       return state;
> +}
> +
>  static struct scp *init_scp(struct platform_device *pdev,
>                         const struct scp_domain_data *scp_domain_data, int num,
>                         const struct scp_ctrl_reg *scp_ctrl_reg,