[PATCH V4 0/4] cpufreq: Migrate away from ->stop_cpu() callback

[PATCH V4 0/4] cpufreq: Migrate away from ->stop_cpu() callback

[Viresh Kumar]

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

[PATCH V4 4/4] cpufreq: Remove stop_cpu() callback

[Viresh Kumar]

Now that all users of stop_cpu() are migrated to use other callbacks,
lets remove its support from the core.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 Documentation/cpu-freq/cpu-drivers.rst                    | 3 ---
 Documentation/translations/zh_CN/cpu-freq/cpu-drivers.rst | 3 ---
 drivers/cpufreq/cpufreq.c                                 | 3 ---
 include/linux/cpufreq.h                                   | 1 -
 4 files changed, 10 deletions(-)

diff --git a/Documentation/cpu-freq/cpu-drivers.rst b/Documentation/cpu-freq/cpu-drivers.rst
index a697278ce190..74fac797c396 100644
--- a/Documentation/cpu-freq/cpu-drivers.rst
+++ b/Documentation/cpu-freq/cpu-drivers.rst
@@ -71,9 +71,6 @@ And optionally
  .exit - A pointer to a per-policy cleanup function called during
  CPU_POST_DEAD phase of cpu hotplug process.
 
- .stop_cpu - A pointer to a per-policy stop function called during
- CPU_DOWN_PREPARE phase of cpu hotplug process.
-
  .suspend - A pointer to a per-policy suspend function which is called
  with interrupts disabled and _after_ the governor is stopped for the
  policy.
diff --git a/Documentation/translations/zh_CN/cpu-freq/cpu-drivers.rst b/Documentation/translations/zh_CN/cpu-freq/cpu-drivers.rst
index 0ca2cb646666..9570e9c9e939 100644
--- a/Documentation/translations/zh_CN/cpu-freq/cpu-drivers.rst
+++ b/Documentation/translations/zh_CN/cpu-freq/cpu-drivers.rst
@@ -76,9 +76,6 @@ 并且可选择
  .exit - 一个指向per-policy清理函数的指针，该函数在cpu热插拔过程的CPU_POST_DEAD
  阶段被调用。
 
- .stop_cpu - 一个指向per-policy停止函数的指针，该函数在cpu热插拔过程的CPU_DOWN_PREPARE
- 阶段被调用。
-
  .suspend - 一个指向per-policy暂停函数的指针，该函数在关中断且在该策略的调节器停止
  后被调用。
 
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index cbab834c37a0..5e4b5316d254 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1606,9 +1606,6 @@ static int cpufreq_offline(unsigned int cpu)
 		policy->cdev = NULL;
 	}
 
-	if (cpufreq_driver->stop_cpu)
-		cpufreq_driver->stop_cpu(policy);
-
 	if (has_target())
 		cpufreq_exit_governor(policy);
 
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 353969c7acd3..2e2267a36502 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -371,7 +371,6 @@ struct cpufreq_driver {
 	int		(*online)(struct cpufreq_policy *policy);
 	int		(*offline)(struct cpufreq_policy *policy);
 	int		(*exit)(struct cpufreq_policy *policy);
-	void		(*stop_cpu)(struct cpufreq_policy *policy);
 	int		(*suspend)(struct cpufreq_policy *policy);
 	int		(*resume)(struct cpufreq_policy *policy);
 
-- 
2.31.1.272.g89b43f80a514