linux-kernel - RE: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver

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Message-ID: <017f01d3edb7$ec160320$c4420960$@codeaurora.org>
Date:   Thu, 17 May 2018 11:20:24 +0300
From:   <ilialin@...eaurora.org>
To:     "'Viresh Kumar'" <viresh.kumar@...aro.org>,
        "'Amit Kucheria'" <amit.kucheria@...aro.org>
Cc:     "'Michael Turquette'" <mturquette@...libre.com>,
        <sboyd@...nel.org>, "'Rob Herring'" <robh@...nel.org>,
        "'Mark Rutland'" <mark.rutland@....com>, <nm@...com>,
        <lgirdwood@...il.com>, <broonie@...nel.org>,
        "'Andy Gross'" <andy.gross@...aro.org>,
        "'David Brown'" <david.brown@...aro.org>,
        <catalin.marinas@....com>, <will.deacon@....com>,
        "'Rafael J. Wysocki'" <rjw@...ysocki.net>,
        <linux-clk@...r.kernel.org>, <devicetree@...r.kernel.org>,
        "'LKML'" <linux-kernel@...r.kernel.org>,
        "'Linux PM list'" <linux-pm@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-soc@...r.kernel.org>,
        "'lakml'" <linux-arm-kernel@...ts.infradead.org>,
        "'Rajendra Nayak'" <rnayak@...eaurora.org>,
        <nicolas.dechesne@...aro.org>, <celster@...eaurora.org>,
        <tfinkel@...eaurora.org>
Subject: RE: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver



> -----Original Message-----
> From: ilialin@...eaurora.org <ilialin@...eaurora.org>
> Sent: Thursday, May 17, 2018 10:51
> To: 'Viresh Kumar' <viresh.kumar@...aro.org>; 'Amit Kucheria'
> <amit.kucheria@...aro.org>
> Cc: 'Michael Turquette' <mturquette@...libre.com>; 'sboyd@...nel.org'
> <sboyd@...nel.org>; 'Rob Herring' <robh@...nel.org>; 'Mark Rutland'
> <mark.rutland@....com>; 'nm@...com' <nm@...com>;
> 'lgirdwood@...il.com' <lgirdwood@...il.com>; 'broonie@...nel.org'
> <broonie@...nel.org>; 'Andy Gross' <andy.gross@...aro.org>; 'David Brown'
> <david.brown@...aro.org>; 'catalin.marinas@....com'
> <catalin.marinas@....com>; 'will.deacon@....com'
> <will.deacon@....com>; 'Rafael J. Wysocki' <rjw@...ysocki.net>; 'linux-
> clk@...r.kernel.org' <linux-clk@...r.kernel.org>;
> 'devicetree@...r.kernel.org' <devicetree@...r.kernel.org>; 'LKML' <linux-
> kernel@...r.kernel.org>; 'Linux PM list' <linux-pm@...r.kernel.org>;
'linux-
> arm-msm@...r.kernel.org' <linux-arm-msm@...r.kernel.org>; 'linux-
> soc@...r.kernel.org' <linux-soc@...r.kernel.org>; 'lakml' <linux-arm-
> kernel@...ts.infradead.org>; 'Rajendra Nayak' <rnayak@...eaurora.org>;
> 'nicolas.dechesne@...aro.org' <nicolas.dechesne@...aro.org>;
> 'celster@...eaurora.org' <celster@...eaurora.org>;
> 'tfinkel@...eaurora.org' <tfinkel@...eaurora.org>
> Subject: RE: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver
> 
> 
> 
> > -----Original Message-----
> > From: Viresh Kumar <viresh.kumar@...aro.org>
> > Sent: Wednesday, May 16, 2018 17:12
> > To: Amit Kucheria <amit.kucheria@...aro.org>
> > Cc: Ilia Lin <ilialin@...eaurora.org>; Michael Turquette
> > <mturquette@...libre.com>; sboyd@...nel.org; Rob Herring
> > <robh@...nel.org>; Mark Rutland <mark.rutland@....com>; nm@...com;
> > lgirdwood@...il.com; broonie@...nel.org; Andy Gross
> > <andy.gross@...aro.org>; David Brown <david.brown@...aro.org>;
> > catalin.marinas@....com; will.deacon@....com; Rafael J. Wysocki
> > <rjw@...ysocki.net>; linux-clk@...r.kernel.org;
> > devicetree@...r.kernel.org; LKML <linux-kernel@...r.kernel.org>; Linux
> > PM list <linux-pm@...r.kernel.org>; linux-arm-msm@...r.kernel.org;
> > linux- soc@...r.kernel.org; lakml
> > <linux-arm-kernel@...ts.infradead.org>;
> > Rajendra Nayak <rnayak@...eaurora.org>; nicolas.dechesne@...aro.org;
> > celster@...eaurora.org; tfinkel@...eaurora.org
> > Subject: Re: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver
> >
> > On 16-05-18, 16:12, Amit Kucheria wrote:
> > > > +       ret = PTR_ERR_OR_ZERO(opp_temp =
> > > > +
> > dev_pm_opp_set_supported_hw(cpu_dev,&versions,1));
> > > > +       if (0 > ret)
> > >
> > > Any particular reason to prefer this over (ret < 0) that is
> > > generally used? I've seen it used to avoid the == vs. = typos, but
> > > not for other comparisons.
> > >
> > > Suggest sticking to what is commonly used i.e. ret < 0.
> > >
> > > > +               goto free_opp;
> > > > +
> > > > +       cpu_dev = get_cpu_device(GOLD_LEAD);
> > >
> > > Error check cpu_dev here?
> > >
> > > > +       ret = PTR_ERR_OR_ZERO(opp_temp =
> > > > +
> > dev_pm_opp_set_supported_hw(cpu_dev,&versions,1));
> > > > +       if (0 > ret)
> > > > +               goto free_opp;
> >
> > The goto here is wrong
> 
> If we are here, then the first dev_pm_opp_set_supported_hw() succeeded.
> And should be deallocated before exit with error.

My bad. Got you.

> 
> >
> > > > +
> > > > +
> > > > +       ret =
> > PTR_ERR_OR_ZERO(platform_device_register_simple("cpufreq-dt",
> > > > +                                                             -1,
> > > > + NULL, 0));
> > > > +
> > > > +       if (0 == ret)
> > > > +               return 0;
> > > > +
> > > > +free_opp:
> > > > +       dev_pm_opp_put_supported_hw(opp_temp);
> > >
> > > This is not needed because dev_pm_opp_set_supported_hw will free
> > > memory in case of failure. This call in only needed in case of a
> > > successful get.
> >
> > But this is still required for the case where platform device
registration fails.
> >
> > --
> > viresh