[v6,09/25] kernel/cpu_pm: Manage runtime PM in the idle path for CPUs

Message ID 1521046715-30683-10-git-send-email-ulf.hansson@linaro.org
State Superseded
Headers show
Series
  • PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM)
Related show

Commit Message

Ulf Hansson March 14, 2018, 4:58 p.m.
To allow CPUs being power managed by PM domains, let's deploy support for
runtime PM for the CPU's corresponding struct device.

More precisely, at the point when the CPU is about to enter an idle state,
decrease the runtime PM usage count for its corresponding struct device,
via calling pm_runtime_put_sync_suspend(). Then, at the point when the CPU
resumes from idle, let's increase the runtime PM usage count, via calling
pm_runtime_get_sync().

Cc: Lina Iyer <ilina@codeaurora.org>
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

---
 kernel/cpu_pm.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

-- 
2.7.4

Patch

diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
index 67b02e1..71317ff 100644
--- a/kernel/cpu_pm.c
+++ b/kernel/cpu_pm.c
@@ -16,9 +16,11 @@ 
  */
 
 #include <linux/kernel.h>
+#include <linux/cpu.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>
 
@@ -91,6 +93,7 @@  int cpu_pm_enter(void)
 {
 	int nr_calls;
 	int ret = 0;
+	struct device *dev = get_cpu_device(smp_processor_id());
 
 	ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
 	if (ret)
@@ -100,6 +103,9 @@  int cpu_pm_enter(void)
 		 */
 		cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
 
+	if (!ret && dev)
+		pm_runtime_put_sync_suspend(dev);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cpu_pm_enter);
@@ -118,6 +124,11 @@  EXPORT_SYMBOL_GPL(cpu_pm_enter);
  */
 int cpu_pm_exit(void)
 {
+	struct device *dev = get_cpu_device(smp_processor_id());
+
+	if (dev)
+		pm_runtime_get_sync(dev);
+
 	return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
 }
 EXPORT_SYMBOL_GPL(cpu_pm_exit);