[PATCH v2 4/7] cpuidle: psci-domain: Enable system-wide suspend on PREEMPT_RT

Ulf Hansson
2024-05-27T14:26:15Z

The domain-idle-states are currently disabled on a PREEMPT_RT based
configuration for the cpuidle-psci-domain. To enable them to be used for
system-wide suspend and in particular during s2idle, let's set the
GENPD_FLAG_RPM_ALWAYS_ON instead of GENPD_FLAG_ALWAYS_ON for the
corresponding genpd provider.

In this way, the runtime PM path remains disabled in genpd for its attached
devices, while powering-on/off the PM domain during system-wide suspend
becomes allowed.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
Changes in v2:
- None.
---
drivers/cpuidle/cpuidle-psci-domain.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index fae958794339..ea28b73ef3fb 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -67,12 +67,16 @@ static int psci_pd_init(struct device_node *np, bool use_osi)

/*
* Allow power off when OSI has been successfully enabled.
- * PREEMPT_RT is not yet ready to enter domain idle states.
+ * On a PREEMPT_RT based configuration the domain idle states are
+ * supported, but only during system-wide suspend.
*/
- if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT))
+ if (use_osi) {
pd->power_off = psci_pd_power_off;
- else
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
+ } else {
pd->flags |= GENPD_FLAG_ALWAYS_ON;
+ }

/* Use governor for CPU PM domains if it has some states to manage. */
pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
--
2.34.1