From: Dmitry Osipenko <digetx@gmail.com>
To: Viresh Kumar <viresh.kumar@linaro.org>, sumitg <sumitg@nvidia.com>
Cc: rjw@rjwysocki.net, catalin.marinas@arm.com, will@kernel.org,
thierry.reding@gmail.com, jonathanh@nvidia.com, talho@nvidia.com,
linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, bbasu@nvidia.com,
mperttunen@nvidia.com
Subject: Re: [TEGRA194_CPUFREQ Patch 2/3] cpufreq: Add Tegra194 cpufreq driver
Date: Wed, 4 Dec 2019 16:57:53 +0300 [thread overview]
Message-ID: <0b634341-ea2b-e9cd-4986-dc9a01c839bb@gmail.com> (raw)
In-Reply-To: <20191204112749.jkwlyteal4hfvnhb@vireshk-i7>
04.12.2019 14:27, Viresh Kumar пишет:
> On 04-12-19, 16:25, sumitg wrote:
>> In T194, CCPLEX doesn't have access to set clocks and the
>>
>> clk_{get|set}_rate() functions set clocks by hook to BPMP R5.
>>
>> CPU freq can be directly set by CCPLEX using MSR(NVFREQ_REQ_EL1).
>>
>> As DVFS run's on BPMP, another MSR (NVFREQ_FEEDBACK_EL1) is
>>
>> used to read the counters and calculate "actual" cpu freq at CCPLEX.
>>
>> So, "cpuinfo_cur_freq" node gives the actual cpu frequency and not
>>
>> given by node "scaling_cur_freq".
>
> Right, but why can't this be hidden in the CPU's clk driver instead,
> so cpufreq driver can just do clk_get_rate() and clk_set_rate() ?
What about to make use of dev_pm_opp_register_set_opp_helper()?
>>> - populating cpufreq table, you can probably add OPPs instead using
>>> the same mechanism
>>
>> We are reading available frequencies from BPMP to populate
>>
>> cpufreq table and not using static opp table.
>
> Right and lot of other platforms read it from firmware (I believe BBMP
> is a firmware here), and create OPPs at runtime. Look at this for
> example:
>
> drivers/cpufreq/qcom-cpufreq-hw.c
>
> and search for dev_pm_opp_add().
>
WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Osipenko <digetx@gmail.com>
To: Viresh Kumar <viresh.kumar@linaro.org>, sumitg <sumitg@nvidia.com>
Cc: bbasu@nvidia.com, linux-pm@vger.kernel.org,
catalin.marinas@arm.com, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, jonathanh@nvidia.com,
talho@nvidia.com, thierry.reding@gmail.com,
linux-tegra@vger.kernel.org, mperttunen@nvidia.com,
will@kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [TEGRA194_CPUFREQ Patch 2/3] cpufreq: Add Tegra194 cpufreq driver
Date: Wed, 4 Dec 2019 16:57:53 +0300 [thread overview]
Message-ID: <0b634341-ea2b-e9cd-4986-dc9a01c839bb@gmail.com> (raw)
In-Reply-To: <20191204112749.jkwlyteal4hfvnhb@vireshk-i7>
04.12.2019 14:27, Viresh Kumar пишет:
> On 04-12-19, 16:25, sumitg wrote:
>> In T194, CCPLEX doesn't have access to set clocks and the
>>
>> clk_{get|set}_rate() functions set clocks by hook to BPMP R5.
>>
>> CPU freq can be directly set by CCPLEX using MSR(NVFREQ_REQ_EL1).
>>
>> As DVFS run's on BPMP, another MSR (NVFREQ_FEEDBACK_EL1) is
>>
>> used to read the counters and calculate "actual" cpu freq at CCPLEX.
>>
>> So, "cpuinfo_cur_freq" node gives the actual cpu frequency and not
>>
>> given by node "scaling_cur_freq".
>
> Right, but why can't this be hidden in the CPU's clk driver instead,
> so cpufreq driver can just do clk_get_rate() and clk_set_rate() ?
What about to make use of dev_pm_opp_register_set_opp_helper()?
>>> - populating cpufreq table, you can probably add OPPs instead using
>>> the same mechanism
>>
>> We are reading available frequencies from BPMP to populate
>>
>> cpufreq table and not using static opp table.
>
> Right and lot of other platforms read it from firmware (I believe BBMP
> is a firmware here), and create OPPs at runtime. Look at this for
> example:
>
> drivers/cpufreq/qcom-cpufreq-hw.c
>
> and search for dev_pm_opp_add().
>
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next prev parent reply other threads:[~2019-12-04 13:57 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 17:32 [TEGRA194_CPUFREQ Patch 1/3] firmware: tegra: adding function to get BPMP data Sumit Gupta
2019-12-03 17:32 ` Sumit Gupta
2019-12-03 17:32 ` Sumit Gupta
2019-12-03 17:32 ` [TEGRA194_CPUFREQ Patch 2/3] cpufreq: Add Tegra194 cpufreq driver Sumit Gupta
2019-12-03 17:32 ` Sumit Gupta
2019-12-03 17:32 ` Sumit Gupta
2019-12-04 5:40 ` Viresh Kumar
2019-12-04 5:40 ` Viresh Kumar
2019-12-04 10:55 ` sumitg
2019-12-04 10:55 ` sumitg
2019-12-04 10:55 ` sumitg
2019-12-04 11:27 ` Viresh Kumar
2019-12-04 11:27 ` Viresh Kumar
2019-12-04 13:57 ` Dmitry Osipenko [this message]
2019-12-04 13:57 ` Dmitry Osipenko
2019-12-05 2:51 ` Viresh Kumar
2019-12-05 2:51 ` Viresh Kumar
2019-12-05 12:55 ` Dmitry Osipenko
2019-12-05 12:55 ` Dmitry Osipenko
2020-03-25 23:59 ` sumitg
2020-03-25 23:59 ` sumitg
2020-03-25 23:59 ` sumitg
2019-12-04 13:59 ` Dmitry Osipenko
2019-12-04 13:59 ` Dmitry Osipenko
2019-12-05 14:15 ` Dmitry Osipenko
2019-12-05 14:15 ` Dmitry Osipenko
2020-03-26 11:50 ` Viresh Kumar
2020-03-26 11:50 ` Viresh Kumar
2020-03-26 11:50 ` Viresh Kumar
2020-04-04 18:38 ` sumitg
2020-04-04 18:38 ` sumitg
2020-04-04 18:38 ` sumitg
2020-04-06 2:55 ` Viresh Kumar
2020-04-06 2:55 ` Viresh Kumar
2020-04-06 2:55 ` Viresh Kumar
2020-04-07 18:18 ` sumitg
2020-04-07 18:18 ` sumitg
2020-04-07 18:18 ` sumitg
2020-04-08 5:53 ` Viresh Kumar
2020-04-08 5:53 ` Viresh Kumar
2020-04-08 5:53 ` Viresh Kumar
2020-04-08 11:24 ` sumitg
2020-04-08 11:24 ` sumitg
2020-04-08 11:24 ` sumitg
2020-04-09 7:44 ` Viresh Kumar
2020-04-09 7:44 ` Viresh Kumar
2020-04-09 7:44 ` Viresh Kumar
2020-04-09 11:21 ` Sumit Gupta
2020-04-09 11:21 ` Sumit Gupta
2020-04-09 11:21 ` Sumit Gupta
2020-04-13 6:21 ` Viresh Kumar
2020-04-13 6:21 ` Viresh Kumar
2020-04-13 6:21 ` Viresh Kumar
2020-04-13 12:20 ` Sumit Gupta
2020-04-13 12:20 ` Sumit Gupta
2020-04-13 12:20 ` Sumit Gupta
2020-04-14 5:45 ` Viresh Kumar
2020-04-14 5:45 ` Viresh Kumar
2020-04-14 5:45 ` Viresh Kumar
2020-04-15 11:25 ` Sumit Gupta
2020-04-15 11:25 ` Sumit Gupta
2020-04-15 11:25 ` Sumit Gupta
2020-04-16 3:37 ` Viresh Kumar
2020-04-16 3:37 ` Viresh Kumar
2020-04-16 3:37 ` Viresh Kumar
2020-04-16 7:06 ` Sumit Gupta
2020-04-16 7:06 ` Sumit Gupta
2020-04-16 7:06 ` Sumit Gupta
2019-12-03 17:32 ` [TEGRA194_CPUFREQ Patch 3/3] arm64: defconfig: Enable CONFIG_ARM_TEGRA194_CPUFREQ Sumit Gupta
2019-12-03 17:32 ` Sumit Gupta
2019-12-03 17:32 ` Sumit Gupta
2019-12-03 17:42 ` [TEGRA194_CPUFREQ Patch 1/3] firmware: tegra: adding function to get BPMP data Thierry Reding
2019-12-03 17:42 ` Thierry Reding
2019-12-04 8:45 ` Mikko Perttunen
2019-12-04 8:45 ` Mikko Perttunen
2019-12-04 9:17 ` Viresh Kumar
2019-12-04 9:17 ` Viresh Kumar
2019-12-04 9:33 ` Thierry Reding
2019-12-04 9:33 ` Thierry Reding
2019-12-04 9:51 ` Viresh Kumar
2019-12-04 9:51 ` Viresh Kumar
2020-04-07 10:05 ` Thierry Reding
2020-04-07 10:05 ` Thierry Reding
2020-04-07 10:05 ` Thierry Reding
2020-04-27 7:18 ` Thierry Reding
2020-04-27 7:18 ` Thierry Reding
2020-04-27 7:18 ` Thierry Reding
2020-04-29 8:21 ` Sumit Gupta
2020-04-29 8:21 ` Sumit Gupta
2020-04-29 8:21 ` Sumit Gupta
2020-05-06 16:58 ` Thierry Reding
2020-05-06 16:58 ` Thierry Reding
2020-05-20 14:43 ` Rob Herring
2020-05-20 14:43 ` Rob Herring
2020-05-20 14:43 ` Rob Herring
2020-05-20 15:38 ` Thierry Reding
2020-05-20 15:38 ` Thierry Reding
2020-05-20 15:38 ` Thierry Reding
2020-05-20 16:21 ` Rob Herring
2020-05-20 16:21 ` Rob Herring
2020-05-20 16:21 ` Rob Herring
2019-12-04 10:21 ` Mikko Perttunen
2019-12-04 10:21 ` Mikko Perttunen
2019-12-04 10:26 ` Viresh Kumar
2019-12-04 10:26 ` Viresh Kumar
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