[PATCH RFC 09/27] PM / Domains: Attempt runtime suspend of IRQ safe parent domain

[Lina Iyer]

When a sub-domain is powered off, attempt powering off the parent
domains to maximize power savings. A sub-domain that is IRQ safe may
however have a parent that is not IRQ safe and therefore cannot be
powered down in atomic context that the sub-domain may be powered off.

An IRQ safe sub-domain may attempt to power down the parent domain in a
synchronous call, if the parent is also IRQ safe.

Signed-off-by: Lina Iyer <lina.iyer at linaro.org>
---
 drivers/base/power/domain.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 8df43f8..0310e2b 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -44,6 +44,8 @@ static int pm_genpd_alloc_states_names(struct generic_pm_domain *genpd,
 static LIST_HEAD(gpd_list);
 static DEFINE_MUTEX(gpd_list_lock);
 
+static int genpd_poweroff(struct generic_pm_domain *genpd, bool is_async);
+
 static inline int genpd_lock_nosleep(struct generic_pm_domain *genpd,
 					unsigned int subclass)
 	__acquires(&genpd->slock)
@@ -298,6 +300,13 @@ static int __genpd_poweron(struct generic_pm_domain *genpd)
 					&genpd->slave_links,
 					slave_node) {
 		genpd_sd_counter_dec(link->master);
+
+		/* Assume masters that are non-irq safe are always-on */
+		if (genpd->irq_safe && link->master->irq_safe) {
+			genpd_poweroff(link->master, false);
+			continue;
+		}
+
 		genpd_queue_power_off_work(link->master);
 	}
 
@@ -448,6 +457,13 @@ static int genpd_poweroff(struct generic_pm_domain *genpd, bool is_async)
 
 	list_for_each_entry(link, &genpd->slave_links, slave_node) {
 		genpd_sd_counter_dec(link->master);
+
+		/* Assume masters that are non-irq safe are always-on */
+		if (genpd->irq_safe && link->master->irq_safe) {
+			genpd_poweroff(link->master, false);
+			continue;
+		}
+
 		genpd_queue_power_off_work(link->master);
 	}
 
-- 
2.1.4