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Commit 367dc4aa authored Mar 19, 2014 by Dirk Brandewie Committed by Rafael J. Wysocki Mar 20, 2014

cpufreq: Add stop CPU callback to cpufreq_driver interface



This callback allows the driver to do clean up before the CPU is
completely down and its state cannot be modified.  This is used
by the intel_pstate driver to reduce the requested P state prior to
the core going away.  This is required because the requested P state
of the offline core is used to select the package P state. This
effectively sets the floor package P state to the requested P state on
the offline core.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
[rjw: Minor modifications]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent bda9f552

Documentation/cpu-freq/cpu-drivers.txt

+7 −1

Original line number	Original line	Diff line number	Diff line
	@@ -61,7 +61,13 @@ target_index - See below on the differences.

	And optionally		And optionally

	cpufreq_driver.exit - A pointer to a per-CPU cleanup function.		cpufreq_driver.exit - A pointer to a per-CPU cleanup
			function called during CPU_POST_DEAD
			phase of cpu hotplug process.

			cpufreq_driver.stop_cpu - A pointer to a per-CPU stop function
			called during CPU_DOWN_PREPARE phase of
			cpu hotplug process.

	cpufreq_driver.resume - A pointer to a per-CPU resume function		cpufreq_driver.resume - A pointer to a per-CPU resume function
	which is called with interrupts disabled		which is called with interrupts disabled

drivers/cpufreq/cpufreq.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1337,6 +1337,8 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
	pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",		pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
	__func__, new_cpu, cpu);		__func__, new_cpu, cpu);
	}		}
			} else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
			cpufreq_driver->stop_cpu(policy);
	}		}

	return 0;		return 0;

include/linux/cpufreq.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -227,6 +227,7 @@ struct cpufreq_driver {
	int (bios_limit) (int cpu, unsigned int limit);		int (bios_limit) (int cpu, unsigned int limit);

	int (exit) (struct cpufreq_policy policy);		int (exit) (struct cpufreq_policy policy);
			void (stop_cpu) (struct cpufreq_policy policy);
	int (suspend) (struct cpufreq_policy policy);		int (suspend) (struct cpufreq_policy policy);
	int (resume) (struct cpufreq_policy policy);		int (resume) (struct cpufreq_policy policy);
	struct freq_attr **attr;		struct freq_attr **attr;