From: Ulf Hansson <ulf.hansson@linaro.org>
Date: Thu, 10 Oct 2019 12:01:48 +0200
Subject: cpuidle: psci: Manage runtime PM in the idle path
Git-commit: ce85aef570df406fc8cb360e7351024570ef7d4f
Patch-mainline: v5.6-rc1
References: jsc#SLE-12251
In case we have succeeded to attach a CPU to its PM domain, let's deploy
runtime PM support for the corresponding attached device, to allow the CPU
to be powered-managed accordingly.
The triggering point for when runtime PM reference counting should be done,
has been selected to the deepest idle state for the CPU. However, from the
hierarchical point view, there may be good reasons to do runtime PM
reference counting even on shallower idle states, but at this point this
isn't supported, mainly due to limitations set by the generic PM domain.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
drivers/cpuidle/cpuidle-psci.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 9600fe674a89..6e7804e697ed 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -16,6 +16,7 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/psci.h>
+#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <asm/cpuidle.h>
@@ -51,14 +52,21 @@ static int psci_enter_domain_idle_state(struct cpuidle_device *dev,
{
struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data);
u32 *states = data->psci_states;
- u32 state = psci_get_domain_state();
+ struct device *pd_dev = data->dev;
+ u32 state;
int ret;
+ /* Do runtime PM to manage a hierarchical CPU toplogy. */
+ pm_runtime_put_sync_suspend(pd_dev);
+
+ state = psci_get_domain_state();
if (!state)
state = states[idx];
ret = psci_enter_state(idx, state);
+ pm_runtime_get_sync(pd_dev);
+
/* Clear the domain state to start fresh when back from idle. */
psci_set_domain_state(0);
return ret;
--
2.26.2