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authorDirk Brandewie <dirk.j.brandewie@intel.com>2014-03-19 08:45:53 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-03-20 03:50:12 +0100
commit367dc4aa932bfb33a3189064d33f7890a8ec1ca8 (patch)
treefde9bd6004ff7852da144a373dd1c0536521efef
parentbda9f552f9826313ef8a477fc8e4891de9ae5e73 (diff)
downloadlinux-367dc4aa932bfb33a3189064d33f7890a8ec1ca8.tar.bz2
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>
-rw-r--r--Documentation/cpu-freq/cpu-drivers.txt8
-rw-r--r--drivers/cpufreq/cpufreq.c2
-rw-r--r--include/linux/cpufreq.h1
3 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
index 8b1a4451422e..48da5fdcb9f1 100644
--- a/Documentation/cpu-freq/cpu-drivers.txt
+++ b/Documentation/cpu-freq/cpu-drivers.txt
@@ -61,7 +61,13 @@ target_index - See below on the differences.
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
which is called with interrupts disabled
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 3c56c4759aa1..3aa7a7a226b3 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -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",
__func__, new_cpu, cpu);
}
+ } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
+ cpufreq_driver->stop_cpu(policy);
}
return 0;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 70929bcf1a9d..2d2e62c8666a 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -227,6 +227,7 @@ struct cpufreq_driver {
int (*bios_limit) (int cpu, unsigned int *limit);
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);
struct freq_attr **attr;