linux-kernel - [PATCH V4 0/4] cpufreq: Migrate away from ->stop

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Date:   Wed, 23 Jun 2021 09:54:38 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rafael Wysocki <rjw@...ysocki.net>, Alex Shi <alexs@...nel.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Jonathan Corbet <corbet@....net>, 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-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH V4 0/4] cpufreq: Migrate away from ->stop_cpu() callback

Hi Rafael,

These are based on your patch [1] now.

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 offline() or exit() callback instead of stop_cpu().

V3->V4:
- Based on a cleanup patch [1] from Rafael, apart from 5.13-rc7.
- No need to update exit() for intel pstate anymore.
- Remove the stop_cpu() callback completely.

--
Viresh

[1] https://lore.kernel.org/linux-pm/5490292.DvuYhMxLoT@kreacher/

Viresh Kumar (4):
  cpufreq: cppc: Migrate to ->exit() callback instead of ->stop_cpu()
  cpufreq: intel_pstate: Migrate to ->offline() instead of ->stop_cpu()
  cpufreq: powerenv: Migrate to ->exit() callback instead of
    ->stop_cpu()
  cpufreq: Remove stop_cpu() callback

 Documentation/cpu-freq/cpu-drivers.rst        |  3 --
 .../zh_CN/cpu-freq/cpu-drivers.rst            |  3 --
 drivers/cpufreq/cppc_cpufreq.c                | 46 ++++++++++---------
 drivers/cpufreq/cpufreq.c                     |  3 --
 drivers/cpufreq/intel_pstate.c                | 10 +---
 drivers/cpufreq/powernv-cpufreq.c             | 23 ++++------
 include/linux/cpufreq.h                       |  1 -
 7 files changed, 35 insertions(+), 54 deletions(-)

-- 
2.31.1.272.g89b43f80a514