cpufreq: powernv: Migrate to ->exit() callback instead of ->stop_cpu()

Commit 367dc4aa ("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().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Minor changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/powernv-cpufreq.c

@@ -875,7 +875,15 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 {
-	/* timer is deleted in cpufreq_cpu_stop() */
+	struct powernv_smp_call_data freq_data;
+	struct global_pstate_info *gpstates = policy->driver_data;
+
+	freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
+	freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
+	smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
+	if (gpstates)
+		del_timer_sync(&gpstates->timer);
+
 	kfree(policy->driver_data);
 
 	return 0;
@@ -1007,18 +1015,6 @@ static struct notifier_block powernv_cpufreq_opal_nb = {
 	.priority	= 0,
 };
 
-static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
-{
-	struct powernv_smp_call_data freq_data;
-	struct global_pstate_info *gpstates = policy->driver_data;
-
-	freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
-	freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
-	smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
-	if (gpstates)
-		del_timer_sync(&gpstates->timer);
-}
-
 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
 					unsigned int target_freq)
 {
@@ -1042,7 +1038,6 @@ static struct cpufreq_driver powernv_cpufreq_driver = {
 	.target_index	= powernv_cpufreq_target_index,
 	.fast_switch	= powernv_fast_switch,
 	.get		= powernv_cpufreq_get,
-	.stop_cpu	= powernv_cpufreq_stop_cpu,
 	.attr		= powernv_cpu_freq_attr,
 };