linux-kernel - Re: [PATCH V2 2/2] cpufreq: dt: Refactor initialization to handle probe deferral properly

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Date:   Tue, 1 Sep 2020 12:05:42 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     ulf.hansson@...aro.org, "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>, Nishanth Menon <nm@...com>,
        nks@...wful.org, georgi.djakov@...aro.org,
        Stephan Gerhold <stephan@...hold.net>,
        linux-kernel@...r.kernel.org,
        'Linux Samsung SOC' <linux-samsung-soc@...r.kernel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>
Subject: Re: [PATCH V2 2/2] cpufreq: dt: Refactor initialization to handle
 probe deferral properly

Hi Viresh,

On 01.09.2020 11:45, Viresh Kumar wrote:
> On 01-09-20, 10:57, Marek Szyprowski wrote:
>> This patch landed in linux-next about a week ago. It introduces a
>> following warning on Samsung Exnyos3250 SoC:
>>
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 1000000000, volt: 1150000, enabled: 1. New: freq: 1000000000, volt:
>> 1150000, enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 900000000, volt: 1112500, enabled: 1. New: freq: 900000000, volt:
>> 1112500, enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 800000000, volt: 1075000, enabled: 1. New: freq: 800000000, volt:
>> 1075000, enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 700000000, volt: 1037500, enabled: 1. New: freq: 700000000, volt:
>> 1037500, enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 600000000, volt: 1000000, enabled: 1. New: freq: 600000000, volt:
>> 1000000, enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 500000000, volt: 962500, enabled: 1. New: freq: 500000000, volt: 962500,
>> enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 400000000, volt: 925000, enabled: 1. New: freq: 400000000, volt: 925000,
>> enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 300000000, volt: 887500, enabled: 1. New: freq: 300000000, volt: 887500,
>> enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 200000000, volt: 850000, enabled: 1. New: freq: 200000000, volt: 850000,
>> enabled: 1
>> cpu cpu1: _opp_is_duplicate: duplicate OPPs detected. Existing: freq:
>> 100000000, volt: 850000, enabled: 1. New: freq: 100000000, volt: 850000,
>> enabled: 1
>>
>> I've checked a bit and this is related to the fact that Exynos3250 SoC
>> use OPP-v1 table. Is this intentional? It is not a problem to convert it
>> to OPP-v2 and mark OPP table as shared, but this is a kind of a regression.
> It took me 20 minutes for me to see "where has my patch gone" :(
>
> I wrote a small patch for that to work without any issues, but not
> sure how I missed or abandoned it. Anyway, here is the diff again and
> I will send it out again once you confirm it fixes the issue. Can you
> please also test your driver as a module with multiple insertion/removals ?

Indeed, this patch seems to fix/hide that warning. Feel free to add:

Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>

Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> index 5dac8bffd68c..e72753be7dc7 100644
> --- a/drivers/opp/of.c
> +++ b/drivers/opp/of.c
> @@ -905,6 +905,16 @@ static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
>          const __be32 *val;
>          int nr, ret = 0;
>   
> +       mutex_lock(&opp_table->lock);
> +       if (opp_table->parsed_static_opps) {
> +               opp_table->parsed_static_opps++;
> +               mutex_unlock(&opp_table->lock);
> +               return 0;
> +       }
> +
> +       opp_table->parsed_static_opps = 1;
> +       mutex_unlock(&opp_table->lock);
> +
>          prop = of_find_property(dev->of_node, "operating-points", NULL);
>          if (!prop)
>                  return -ENODEV;
> @@ -921,10 +931,6 @@ static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
>                  return -EINVAL;
>          }
>   
> -       mutex_lock(&opp_table->lock);
> -       opp_table->parsed_static_opps = 1;
> -       mutex_unlock(&opp_table->lock);
> -
>          val = prop->value;
>          while (nr) {
>                  unsigned long freq = be32_to_cpup(val++) * 1000;
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland