From: Dirk Brandewie <dirk.j.brande...@intel.com>
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.brande...@intel.com>
---
Documentation/cpu-freq/cpu-drivers.txt | 8 +++++++-
drivers/cpufreq/cpufreq.c | 3 +++
include/linux/cpufreq.h | 1 +
3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/Documentation/cpu-freq/cpu-drivers.txt
b/Documentation/cpu-freq/cpu-drivers.txt
index 8b1a445..935f274 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.exit_prepare - A pointer to a per-CPU cleanup 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 cf485d9..5c9bbfa 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1338,6 +1338,9 @@ static int __cpufreq_remove_dev_prepare(struct device
*dev,
}
}
+ if (cpufreq_driver->exit_prepare)
+ cpufreq_driver->exit_prepare(policy);
+
return 0;
}
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 4d89e0e..5fa94ad 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -224,6 +224,7 @@ struct cpufreq_driver {
int (*bios_limit) (int cpu, unsigned int *limit);
int (*exit) (struct cpufreq_policy *policy);
+ int (*exit_prepare) (struct cpufreq_policy *policy);
int (*suspend) (struct cpufreq_policy *policy);
int (*resume) (struct cpufreq_policy *policy);
struct freq_attr **attr;
--
1.8.3.1
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