linux-kernel - RE: [PATCH 10/12] cpufreq: cpufreq: export cpufreq cpu release and acquire

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Message-ID: <CH0PR12MB5265A2BD890DDA357FD7969D9C829@CH0PR12MB5265.namprd12.prod.outlook.com>
Date:   Fri, 8 Jul 2022 11:46:47 +0000
From:   "Yuan, Perry" <Perry.Yuan@....com>
To:     "Fontenot, Nathan" <Nathan.Fontenot@....com>,
        "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
        "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
        "Huang, Ray" <Ray.Huang@....com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "Sharma, Deepak" <Deepak.Sharma@....com>,
        "Limonciello, Mario" <Mario.Limonciello@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Su, Jinzhou (Joe)" <Jinzhou.Su@....com>,
        "Huang, Shimmer" <Shimmer.Huang@....com>,
        "Du, Xiaojian" <Xiaojian.Du@....com>,
        "Meng, Li (Jassmine)" <Li.Meng@....com>
Subject: RE: [PATCH 10/12] cpufreq: cpufreq: export cpufreq cpu release and
 acquire

[AMD Official Use Only - General]

Hi Nathon. 

> -----Original Message-----
> From: Fontenot, Nathan <Nathan.Fontenot@....com>
> Sent: Friday, July 8, 2022 3:40 AM
> To: Yuan, Perry <Perry.Yuan@....com>; rafael.j.wysocki@...el.com;
> viresh.kumar@...aro.org; Huang, Ray <Ray.Huang@....com>; Rafael J.
> Wysocki <rafael@...nel.org>; linux-pm@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Cc: Sharma, Deepak <Deepak.Sharma@....com>; Limonciello, Mario
> <Mario.Limonciello@....com>; Fontenot, Nathan
> <Nathan.Fontenot@....com>; Deucher, Alexander
> <Alexander.Deucher@....com>; Su, Jinzhou (Joe) <Jinzhou.Su@....com>;
> Huang, Shimmer <Shimmer.Huang@....com>; Du, Xiaojian
> <Xiaojian.Du@....com>; Meng, Li (Jassmine) <Li.Meng@....com>
> Subject: Re: [PATCH 10/12] cpufreq: cpufreq: export cpufreq cpu release and
> acquire
> 
> On 7/7/22 12:01, Perry Yuan wrote:
> > cpufreq_cpu_release" and "cpufreq_cpu_acquire" are only used
> > internally by drivers/cpufreq/cpufreq.c currently.
> > Export them so that other drivers such as the AMD P-state driver can use
> them as well.
> >
> 
> Can you provide more information on why this is needed for the amd-
> pstate driver?
> 
> This patch exports the acquire/release functions but I don't see that the
> amd-pstate driver is updated to use them.
> 
> -Nathan

It is used in the next CPPC EPP patch set which will be sent out soon.
As the amd-pstate is built as module driver, this patch exports the symbol to pstate driver. 

Perry.

> 
> > Signed-off-by: Perry Yuan <Perry.Yuan@....com>
> > ---
> >  drivers/cpufreq/cpufreq.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index 73432360e6e9..4d3c83da29b7 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -262,6 +262,7 @@ void cpufreq_cpu_release(struct cpufreq_policy
> > *policy)
> >
> >  	cpufreq_cpu_put(policy);
> >  }
> > +EXPORT_SYMBOL_GPL(cpufreq_cpu_release);
> >
> >  /**
> >   * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
> > @@ -291,6 +292,7 @@ struct cpufreq_policy
> > *cpufreq_cpu_acquire(unsigned int cpu)
> >
> >  	return policy;
> >  }
> > +EXPORT_SYMBOL_GPL(cpufreq_cpu_acquire);
> >
> >
> /**************************************************************
> *******
> >   *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *