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

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Date:   Fri, 16 Oct 2020 10:33:47 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Stephan Gerhold <stephan@...hold.net>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Linux PM list <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 <georgi.djakov@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Linux I2C <linux-i2c@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH V2 2/2] cpufreq: dt: Refactor initialization to handle
 probe deferral properly

On 14-10-20, 18:40, Geert Uytterhoeven wrote:
> On this platform (r8a7791-koelsch.dts), there is no opp table in DT.
> 
>   Before:

I assume this means before this patchset came in..

>     boot:
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:362
>       cpu cpu0: resources_available:95
>       cpu cpu0: resources_available:102: clk_get() returned z
>       cpu cpu0: resources_available:120:
> dev_pm_opp_of_find_icc_paths() returned 0
>       cpu cpu0: resources_available:125: find_supply_name() returned cpu0
>       cpu cpu0: resources_available:132: regulator_get_optional()
> returned -EPROBE_DEFER
>       cpu cpu0: cpu0 regulator not ready, retry
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:371:
> resources_available() returned -517

we deferred probe once.

>       ...
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:362
>       cpu cpu0: resources_available:95
>       cpu cpu0: resources_available:102: clk_get() returned z
>       cpu cpu0: resources_available:120:
> dev_pm_opp_of_find_icc_paths() returned 0
>       cpu cpu0: resources_available:125: find_supply_name() returned cpu0
>       cpu cpu0: resources_available:132: regulator_get_optional()
> returned (ptrval)

found regulator next time.

>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:371:
> resources_available() returned 0
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:375
>       cpufreq_dt: cpufreq_init:162
>       cpu cpu0: cpufreq_init:170: clk_get() returned z
>       cpu cpu0: cpufreq_init:179: dev_pm_opp_of_get_sharing_cpus() returned -2
>       cpu cpu0: cpufreq_init:198: find_supply_name() returned cpu0
>       <i2c comm>
>       cpu cpu0: cpufreq_init:201: dev_pm_opp_set_regulators() returned (ptrval)
>       <i2c comm>
>       cpu cpu0: cpufreq_init:230: dev_pm_opp_of_cpumask_add_table() returned 0
>       cpu cpu0: cpufreq_init:239: dev_pm_opp_get_opp_count() returned 0
>       cpu cpu0: OPP table is not ready, deferring probe

This failed, as we couldn't have deferred probe from cpufreq_init.
Which means that cpufreq didn't work here.

>       cpufreq_dt: cpufreq_init:162
>       cpu cpu1: cpufreq_init:170: clk_get() returned z
>       cpu cpu1: cpufreq_init:179: dev_pm_opp_of_get_sharing_cpus() returned -2
>       cpu cpu1: no regulator for cpu1
>       cpu cpu1: cpufreq_init:198: find_supply_name() returned (null)
>       cpu cpu1: cpufreq_init:230: dev_pm_opp_of_cpumask_add_table() returned 0
>       cpu cpu1: cpufreq_init:239: dev_pm_opp_get_opp_count() returned 0
>       cpu cpu1: OPP table is not ready, deferring probe

Same for CPU1.

> 
>     s2ram:
>       cpufreq_dt: cpufreq_init:162
>       cpu cpu1: cpufreq_init:170: clk_get() returned z
>       cpu cpu1: cpufreq_init:179: dev_pm_opp_of_get_sharing_cpus() returned -2
>       cpu cpu1: no regulator for cpu1
>       cpu cpu1: cpufreq_init:198: find_supply_name() returned (null)
>       cpu cpu1: cpufreq_init:230: dev_pm_opp_of_cpumask_add_table() returned 0
>       cpu cpu1: cpufreq_init:239: dev_pm_opp_get_opp_count() returned 0
>       cpu cpu1: OPP table is not ready, deferring probe

And same here.

>       CPU1 is up
> 
>   After:
>     boot:
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:356
>       cpufreq_dt: dt_cpufreq_early_init:251
>       cpu cpu0: dt_cpufreq_early_init:256
>       cpu cpu0: dt_cpufreq_early_init:271: dev_pm_opp_get_opp_table()
> returned (ptrval)
>       cpu cpu0: dt_cpufreq_early_init:284: find_supply_name() returned cpu0
>       cpu cpu0: dt_cpufreq_early_init:288: dev_pm_opp_set_regulators()
> returned -EPROBE_DEFER
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:360:
> dt_cpufreq_early_init() returned -517
>       ...
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:356
>       cpufreq_dt: dt_cpufreq_early_init:251
>       cpu cpu0: dt_cpufreq_early_init:256
>       cpu cpu0: dt_cpufreq_early_init:271: dev_pm_opp_get_opp_table()
> returned (ptrval)
>       cpu cpu0: dt_cpufreq_early_init:284: find_supply_name() returned cpu0
>       cpu cpu0: dt_cpufreq_early_init:288: dev_pm_opp_set_regulators()
> returned (ptrval)
>       cpu cpu0: dt_cpufreq_early_init:301:
> dev_pm_opp_of_get_sharing_cpus() returned -2
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:360:
> dt_cpufreq_early_init() returned 0
>       cpufreq_dt: dt_cpufreq_early_init:251
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:360:
> dt_cpufreq_early_init() returned 0
>       cpufreq-dt cpufreq-dt: dt_cpufreq_probe:365
>       cpufreq_dt: cpufreq_init:114
>       cpu cpu0: cpufreq_init:124: clk_get() returned z
>       cpu cpu0: cpufreq_init:142: dev_pm_opp_of_cpumask_add_table() returned 0
>       cpu cpu0: cpufreq_init:151: dev_pm_opp_get_opp_count() returned 0
>       cpu cpu0: OPP table can't be empty

Same issue here.

>       cpufreq_dt: cpufreq_init:114
>       cpu cpu0: cpufreq_init:124: clk_get() returned z
>       <i2c comm>
>       cpu cpu0: cpufreq_init:142: dev_pm_opp_of_cpumask_add_table() returned 0
>       cpu cpu0: cpufreq_init:151: dev_pm_opp_get_opp_count() returned 0
> 
>     s2ram:
> 
>       cpufreq_dt: cpufreq_init:114
>       cpu cpu0: cpufreq_init:124: clk_get() returned z
>       WARNING: CPU: 1 PID: 14 at drivers/i2c/i2c-core.h:54
> __i2c_transfer+0x2d8/0x310
>       i2c i2c-6: Transfer while suspended
>       cpu cpu0: cpufreq_init:142: dev_pm_opp_of_cpumask_add_table() returned 0
>       cpu cpu0: cpufreq_init:151: dev_pm_opp_get_opp_count() returned 0
>       cpu cpu0: OPP table can't be empty
>       CPU1 is up
> 
> I hope this helps.

Unfortunately it raised more questions than what it answered :(

-- 
viresh