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Date:   Mon, 28 Oct 2019 16:04:43 +0200
From:   Peter De Schrijver <pdeschrijver@nvidia.com>
To:     Dmitry Osipenko <digetx@gmail.com>
CC:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        "Daniel Lezcano" <daniel.lezcano@linaro.org>,
        <linux-pm@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 00/18] Consolidate and improve NVIDIA Tegra CPUIDLE
 driver(s)
Message-ID: <20191028140443.GA27141@pdeschrijver-desktop.Nvidia.com>
References: <20191015170015.1135-1-digetx@gmail.com>
 <20191016192133.GB26038@pdeschrijver-desktop.Nvidia.com>
 <72636eb3-5354-eea3-3a51-4975a04186b2@gmail.com>
 <53ee8bd3-5c53-f0aa-175c-7fa3024d0af5@gmail.com>
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On Wed, Oct 16, 2019 at 11:14:07PM +0300, Dmitry Osipenko wrote:
> 16.10.2019 22:47, Dmitry Osipenko =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> > 16.10.2019 22:21, Peter De Schrijver =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> >> On Tue, Oct 15, 2019 at 07:59:57PM +0300, Dmitry Osipenko wrote:
> >>> Hello,
> >>>
> >>> This series does the following:
> >>>
> >>>   1. Unifies Tegra20/30/114 drivers into a single driver and moves it=
 out
> >>>      into common drivers/cpuidle/ directory.
> >>>
> >>>   2. Enables CPU cluster power-down idling state on Tegra30.
> >>>
> >>> In the end there is a quite nice clean up of the Tegra CPUIDLE driver=
s
> >>> and of the Tegra's arch code in general. Please review, thanks!
> >>>
> >>> Changelog:
> >>>
> >>> v6: - Addressed request from Thierry Reding to change the way patches=
 are
> >>>       organized by making changes in a more incremental manner.
> >>>
> >>>     - tegra_sleep_cpu() now checks for the secondary CPUs to be offli=
ne
> >>>       in the "Make outer_disable() open-coded" patch.
> >>>
> >>> v5: - Rebased on a recent linux-next, fixed one minor conflict in Kco=
nfig.
> >>>
> >>>     - Improved commit's message of the "Support CPU cluster power-dow=
n state
> >>>       on Tegra30" patch.
> >>>
> >>>     - The "Support CPU cluster power-down state on Tegra30" patch is =
also
> >>>       got split and now there is additional "Make outer_disable() ope=
n-coded"
> >>>       patch.
> >>>
> >>>     - Made minor cosmetic changes to the "Introduce unified driver fo=
r
> >>>       NVIDIA Tegra SoCs" patch by improving error message and renamin=
g
> >>>       one variable.
> >>>
> >>> v4: - Fixed compilation with !CONFIG_CACHE_L2X0 (and tested that it s=
till
> >>>       works).
> >>>
> >>>     - Replaced ktime_compare() with ktime_before() in the new driver,
> >>>       for consistency.
> >>>
> >>> v3: - Addressed review comments that were made by Jon Hunter to v2 by
> >>>       splitting patches into smaller (and simpler) chunks, better
> >>>       documenting changes in the commit messages and using proper err=
or
> >>>       codes in the code.
> >>>
> >>>       Warnings are replaced with a useful error messages in the code =
of
> >>>       "Introduce unified driver for NVIDIA Tegra SoCs" patch.
> >>>
> >>>       Secondary CPUs parking timeout increased to 100ms because I fou=
nd
> >>>       that it actually may happen to take more than 1ms if CPU is run=
ning
> >>>       on a *very* low frequency.
> >>>
> >>>       Added diagnostic messages that are reporting Flow Controller st=
ate
> >>>       when CPU parking fails.
> >>>
> >>>       Further polished cpuidle driver's code.
> >>>
> >>>       The coupled state entering is now aborted if there is a pending=
 SGI
> >>>       (Software Generated Interrupt) because it will be lost after GI=
C's
> >>>       power-cycling. Like it was done by the old Tegra20 CPUIDLE driv=
er.
> >>>
> >>> v2: - Added patches to enable the new cpuidle driver in the defconfig=
s:
> >>>
> >>>         ARM: multi_v7_defconfig: Enable Tegra cpuidle driver
> >>>         ARM: tegra: Enable Tegra cpuidle driver in tegra_defconfig
> >>>
> >>>     - Dropped patches that removed CPUIDLE_FLAG_TIMER_STOP from the i=
dling
> >>>       states because that flag actually doesn't have any negative eff=
ects,
> >>>       but still is correct for the case of a local CPU timer on older=
 Tegra
> >>>       SoCs:
> >>>
> >>>         cpuidle: tegra: Remove CPUIDLE_FLAG_TIMER_STOP from Tegra114/=
124 idle-state
> >>>         cpuidle: tegra: Remove CPUIDLE_FLAG_TIMER_STOP from all state=
s
> >>>
> >>>     - The "Add unified driver for NVIDIA Tegra SoCs" patch got more p=
olish.
> >>>       Tegra30 and Terga114 states are now squashed into a single comm=
on C7
> >>>       state (following Parker TRM terminology, see 17.2.2.2 Power Man=
agement
> >>>       States), more comments added, etc minor changes.
> >>
> >> It would be useful to switch the power state terminology to the one us=
ed
> >> for later chips:
> >>
> >> LP0 becomes SC7
> >> LP1 becomes C1
> >> LP2 becomes CC7
> >>
> >> Meaning of these states is as follows
> >>
> >> C is a core state:
> >>
> >> C1 clock gating
> >> C2 not defined
> >> C3 not defined
> >> C4 not defined
> >> C5 not defined
> >> C6 not defined for ARM cores
> >> C7 power-gating
> >>
> >> CC is a CPU cluster C state:
> >>
> >> CC1 cluster clock gated
> >> CC2 not defined
> >> CC3 fmax@Vmin: not used prior to Tegra186
> >> CC4: cluster retention: no longer supported
> >> CC5: not defined
> >> CC6: cluster power gating
> >> CC7: cluster rail gating
> >>
> >> SC is a System C state:
> >>
> >> SC1: not defined
> >> SC2: not defined
> >> SC3: not defined
> >> SC4: not defined
> >> SC5: not defined
> >> SC6: not defined
> >> SC7: VDD_SOC off
> >=20
> > Hello Peter,
> >=20
> > But new "drivers/cpuidle/cpuidle-tegra.c" uses exactly that terminology=
,
> > please see "cpuidle: Refactor and move NVIDIA Tegra20 driver into
> > drivers/cpuidle/" and further patches. Am I missing something? Or do yo=
u
> > want the renaming to be a separate patch?
> >=20
>=20
> Or maybe you're suggesting to change the names everywhere and not only
> in the cpuidle driver? Please clarify :)

At least some of the variable and function names still say lp2?

Peter.