[PATCH V5 3/9] kernel/cpu_pm: Add runtime PM support for CPUs
Lina Iyer
lina.iyer at linaro.org
Fri Mar 3 12:41:29 PST 2017
Notify runtime PM when the CPU is going to be powered off in the idle
state. This allows for runtime PM suspend/resume of the CPU as well as
its PM domain.
Cc: Kevin Hilman <khilman at kernel.org>
Cc: Rafael J. Wysocki <rjw at rjwysocki.net>
Signed-off-by: Lina Iyer <lina.iyer at linaro.org>
---
include/linux/cpuhotplug.h | 1 +
kernel/cpu_pm.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 921acaa..448226a 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -79,6 +79,7 @@ enum cpuhp_state {
CPUHP_AP_OFFLINE,
CPUHP_AP_SCHED_STARTING,
CPUHP_AP_RCUTREE_DYING,
+ CPUHP_AP_CPU_PM_STARTING,
CPUHP_AP_IRQ_GIC_STARTING,
CPUHP_AP_IRQ_HIP04_STARTING,
CPUHP_AP_IRQ_ARMADA_XP_STARTING,
diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
index 009cc9a..db95ef3 100644
--- a/kernel/cpu_pm.c
+++ b/kernel/cpu_pm.c
@@ -16,9 +16,12 @@
*/
#include <linux/kernel.h>
+#include <linux/cpu.h>
+#include <linux/cpuhotplug.h>
#include <linux/cpu_pm.h>
#include <linux/module.h>
#include <linux/notifier.h>
+#include <linux/pm_runtime.h>
#include <linux/spinlock.h>
#include <linux/syscore_ops.h>
@@ -99,6 +102,7 @@ int cpu_pm_enter(void)
{
int nr_calls;
int ret = 0;
+ struct device *dev = get_cpu_device(smp_processor_id());
read_lock(&cpu_pm_notifier_lock);
ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
@@ -110,6 +114,10 @@ int cpu_pm_enter(void)
cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
read_unlock(&cpu_pm_notifier_lock);
+ /* Notify Runtime PM that we are suspending the CPU */
+ if (!ret && dev)
+ RCU_NONIDLE(pm_runtime_put_sync_suspend(dev));
+
return ret;
}
EXPORT_SYMBOL_GPL(cpu_pm_enter);
@@ -129,6 +137,11 @@ EXPORT_SYMBOL_GPL(cpu_pm_enter);
int cpu_pm_exit(void)
{
int ret;
+ struct device *dev = get_cpu_device(smp_processor_id());
+
+ /* Notify Runtime PM that we are resuming the CPU */
+ if (dev)
+ RCU_NONIDLE(pm_runtime_get_sync(dev));
read_lock(&cpu_pm_notifier_lock);
ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
@@ -200,6 +213,40 @@ int cpu_cluster_pm_exit(void)
}
EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
+#ifdef CONFIG_HOTPLUG_CPU
+static int cpu_pm_cpu_dying(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
+
+ if (dev)
+ pm_runtime_put_sync_suspend(dev);
+
+ return 0;
+}
+
+static int cpu_pm_cpu_starting(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
+
+ if (dev)
+ pm_runtime_get_sync(dev);
+
+ return 0;
+}
+
+static int __init cpu_pm_hotplug_init(void)
+{
+ int ret;
+
+ ret = cpuhp_setup_state(CPUHP_AP_CPU_PM_STARTING,
+ "AP_CPU_PM_STARTING",
+ cpu_pm_cpu_starting, cpu_pm_cpu_dying);
+
+ return ret;
+}
+device_initcall(cpu_pm_hotplug_init);
+#endif
+
#ifdef CONFIG_PM
static int cpu_pm_suspend(void)
{
--
2.7.4
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