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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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  reply	other threads:[~2019-12-04 13:58 UTC|newest]

Thread overview: 40+ 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 ` [TEGRA194_CPUFREQ Patch 2/3] cpufreq: Add Tegra194 cpufreq driver Sumit Gupta
2019-12-04  5:40   ` Viresh Kumar
2019-12-04 10:55     ` sumitg
2019-12-04 11:27       ` Viresh Kumar
2019-12-04 13:57         ` Dmitry Osipenko [this message]
2019-12-05  2:51           ` Viresh Kumar
2019-12-05 12:55             ` Dmitry Osipenko
2020-03-25 23:59         ` sumitg
2019-12-04 13:59   ` Dmitry Osipenko
2019-12-05 14:15   ` Dmitry Osipenko
2020-03-26 11:50   ` Viresh Kumar
2020-04-04 18:38     ` sumitg
2020-04-06  2:55       ` Viresh Kumar
2020-04-07 18:18         ` sumitg
2020-04-08  5:53           ` Viresh Kumar
2020-04-08 11:24             ` sumitg
2020-04-09  7:44               ` Viresh Kumar
2020-04-09 11:21                 ` Sumit Gupta
2020-04-13  6:21                   ` Viresh Kumar
2020-04-13 12:20                     ` Sumit Gupta
2020-04-14  5:45                       ` Viresh Kumar
2020-04-15 11:25                         ` Sumit Gupta
2020-04-16  3:37                           ` Viresh Kumar
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 17:42 ` [TEGRA194_CPUFREQ Patch 1/3] firmware: tegra: adding function to get BPMP data Thierry Reding
2019-12-04  8:45   ` Mikko Perttunen
2019-12-04  9:17     ` Viresh Kumar
2019-12-04  9:33       ` Thierry Reding
2019-12-04  9:51         ` Viresh Kumar
2020-04-07 10:05           ` Thierry Reding
2020-04-27  7:18             ` Thierry Reding
2020-04-29  8:21               ` Sumit Gupta
2020-05-06 16:58               ` Thierry Reding
2020-05-20 14:43             ` Rob Herring
2020-05-20 15:38               ` Thierry Reding
2020-05-20 16:21                 ` Rob Herring
2019-12-04 10:21       ` Mikko Perttunen
2019-12-04 10:26         ` Viresh Kumar

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