linux-kernel - [PATCH V2 0/3] cpufreq: Migrate away from ->stop

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Date:   Wed, 16 Jun 2021 12:10:25 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rafael Wysocki <rjw@...ysocki.net>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Len Brown <lenb@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Paul Mackerras <paulus@...ba.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dirk Brandewie <dirk.brandewie@...il.com>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH V2 0/3] cpufreq: Migrate away from ->stop_cpu() callback

Hi Rafael,

Sending these separately from CPPC stuff to avoid unnecessary confusion and
independent merging of these patches. These should get in nevertheless.

commit 367dc4aa932b ("cpufreq: Add stop CPU callback to cpufreq_driver
interface") added the stop_cpu() callback to allow the drivers to do
clean up before the CPU is completely down and its state can't be
modified.

At that time the CPU hotplug framework used to call the cpufreq core's
registered notifier for different events like CPU_DOWN_PREPARE and
CPU_POST_DEAD. The stop_cpu() callback was called during the
CPU_DOWN_PREPARE event.

This is no longer the case, cpuhp_cpufreq_offline() is called only once
by the CPU hotplug core now and we don't really need two separate
callbacks for cpufreq drivers, i.e. stop_cpu() and exit(), as everything
can be done from the exit() callback itself.

Migrate to using the exit() callback instead of stop_cpu().

The stop_cpu() callback isn't removed from core as it will be reused in
a different way in a separate patchset.

--
Viresh

Viresh Kumar (3):
  cpufreq: cppc: Migrate to ->exit() callback instead of ->stop_cpu()
  cpufreq: intel_pstate: Migrate to ->exit() callback instead of
    ->stop_cpu()
  cpufreq: powerenv: Migrate to ->exit() callback instead of
    ->stop_cpu()

 drivers/cpufreq/cppc_cpufreq.c    | 46 ++++++++++++++++---------------
 drivers/cpufreq/intel_pstate.c    |  9 +-----
 drivers/cpufreq/powernv-cpufreq.c | 23 ++++++----------
 3 files changed, 34 insertions(+), 44 deletions(-)

-- 
2.31.1.272.g89b43f80a514