bool default_stop_ok(struct device *dev)
{
struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
+ unsigned long flags;
s64 constraint_ns;
dev_dbg(dev, "%s()\n", __func__);
- constraint_ns = dev_pm_qos_read_value(dev);
+ spin_lock_irqsave(&dev->power.lock, flags);
+
+ if (!td->constraint_changed) {
+ bool ret = td->cached_stop_ok;
+
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+ return ret;
+ }
+ td->constraint_changed = false;
+ td->cached_stop_ok = false;
+ td->effective_constraint_ns = -1;
+ constraint_ns = __dev_pm_qos_read_value(dev);
+
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+
if (constraint_ns < 0)
return false;
constraint_ns *= NSEC_PER_USEC;
/*
* We can walk the children without any additional locking, because
- * they all have been suspended at this point.
+ * they all have been suspended at this point and their
+ * effective_constraint_ns fields won't be modified in parallel with us.
*/
if (!dev->power.ignore_children)
device_for_each_child(dev, &constraint_ns,
return false;
}
td->effective_constraint_ns = constraint_ns;
+ td->cached_stop_ok = constraint_ns > td->stop_latency_ns ||
+ constraint_ns == 0;
/*
* The children have been suspended already, so we don't need to take
* their stop latencies into account here.
*/
- return constraint_ns > td->stop_latency_ns || constraint_ns == 0;
+ return td->cached_stop_ok;
}
/**
struct generic_pm_domain *genpd = pd_to_genpd(pd);
struct gpd_link *link;
struct pm_domain_data *pdd;
- s64 min_dev_off_time_ns;
+ s64 min_off_time_ns;
s64 off_on_time_ns;
- ktime_t time_now = ktime_get();
+
+ if (genpd->max_off_time_changed) {
+ struct gpd_link *link;
+
+ /*
+ * We have to invalidate the cached results for the masters, so
+ * use the observation that default_power_down_ok() is not
+ * going to be called for any master until this instance
+ * returns.
+ */
+ list_for_each_entry(link, &genpd->slave_links, slave_node)
+ link->master->max_off_time_changed = true;
+
+ genpd->max_off_time_changed = false;
+ genpd->cached_power_down_ok = false;
+ genpd->max_off_time_ns = -1;
+ } else {
+ return genpd->cached_power_down_ok;
+ }
off_on_time_ns = genpd->power_off_latency_ns +
genpd->power_on_latency_ns;
to_gpd_data(pdd)->td.save_state_latency_ns;
}
+ min_off_time_ns = -1;
/*
* Check if subdomains can be off for enough time.
*
if (sd_max_off_ns < 0)
continue;
- sd_max_off_ns -= ktime_to_ns(ktime_sub(time_now,
- sd->power_off_time));
/*
* Check if the subdomain is allowed to be off long enough for
* the current domain to turn off and on (that's how much time
*/
if (sd_max_off_ns <= off_on_time_ns)
return false;
+
+ if (min_off_time_ns > sd_max_off_ns || min_off_time_ns < 0)
+ min_off_time_ns = sd_max_off_ns;
}
/*
* Check if the devices in the domain can be off enough time.
*/
- min_dev_off_time_ns = -1;
list_for_each_entry(pdd, &genpd->dev_list, list_node) {
struct gpd_timing_data *td;
- struct device *dev = pdd->dev;
- s64 dev_off_time_ns;
+ s64 constraint_ns;
- if (!dev->driver || dev->power.max_time_suspended_ns < 0)
+ if (!pdd->dev->driver)
continue;
+ /*
+ * Check if the device is allowed to be off long enough for the
+ * domain to turn off and on (that's how much time it will
+ * have to wait worst case).
+ */
td = &to_gpd_data(pdd)->td;
- dev_off_time_ns = dev->power.max_time_suspended_ns -
- (td->start_latency_ns + td->restore_state_latency_ns +
- ktime_to_ns(ktime_sub(time_now,
- dev->power.suspend_time)));
- if (dev_off_time_ns <= off_on_time_ns)
- return false;
-
- if (min_dev_off_time_ns > dev_off_time_ns
- || min_dev_off_time_ns < 0)
- min_dev_off_time_ns = dev_off_time_ns;
- }
+ constraint_ns = td->effective_constraint_ns;
+ /* default_stop_ok() need not be called before us. */
+ if (constraint_ns < 0) {
+ constraint_ns = dev_pm_qos_read_value(pdd->dev);
+ constraint_ns *= NSEC_PER_USEC;
+ }
+ if (constraint_ns == 0)
+ continue;
- if (min_dev_off_time_ns < 0) {
/*
- * There are no latency constraints, so the domain can spend
- * arbitrary time in the "off" state.
+ * constraint_ns cannot be negative here, because the device has
+ * been suspended.
*/
- genpd->max_off_time_ns = -1;
- return true;
+ constraint_ns -= td->restore_state_latency_ns;
+ if (constraint_ns <= off_on_time_ns)
+ return false;
+
+ if (min_off_time_ns > constraint_ns || min_off_time_ns < 0)
+ min_off_time_ns = constraint_ns;
}
+ genpd->cached_power_down_ok = true;
+
/*
- * The difference between the computed minimum delta and the time needed
- * to turn the domain on is the maximum theoretical time this domain can
- * spend in the "off" state.
+ * If the computed minimum device off time is negative, there are no
+ * latency constraints, so the domain can spend arbitrary time in the
+ * "off" state.
*/
- min_dev_off_time_ns -= genpd->power_on_latency_ns;
+ if (min_off_time_ns < 0)
+ return true;
/*
- * If the difference between the computed minimum delta and the time
- * needed to turn the domain off and back on on is smaller than the
- * domain's power break even time, removing power from the domain is not
- * worth it.
+ * The difference between the computed minimum subdomain or device off
+ * time and the time needed to turn the domain on is the maximum
+ * theoretical time this domain can spend in the "off" state.
*/
- if (genpd->break_even_ns >
- min_dev_off_time_ns - genpd->power_off_latency_ns)
- return false;
-
- genpd->max_off_time_ns = min_dev_off_time_ns;
+ genpd->max_off_time_ns = min_off_time_ns - genpd->power_on_latency_ns;
return true;
}