From: Viresh Kumar <viresh.kumar@linaro.org>
To: 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 16:57:49 +0530 [thread overview]
Message-ID: <20191204112749.jkwlyteal4hfvnhb@vireshk-i7> (raw)
In-Reply-To: <7347caa6-43a3-f761-de83-481b45f7b22a@nvidia.com>
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() ?
> >
> > - 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().
--
viresh
next prev parent reply other threads:[~2019-12-04 11:27 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 [this message]
2019-12-04 13:57 ` Dmitry Osipenko
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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