@@ -117,6 +117,56 @@ static bool default_suspend_ok(struct device *dev)
return td->cached_suspend_ok;
}
+static void update_domain_next_wakeup(struct generic_pm_domain *genpd, ktime_t now)
+{
+ ktime_t domain_wakeup = KTIME_MAX;
+ ktime_t next_wakeup;
+ struct pm_domain_data *pdd;
+ struct gpd_link *link;
+
+ /* Find the earliest wakeup for all devices in the domain */
+ list_for_each_entry(pdd, &genpd->dev_list, list_node) {
+ if (pdd->dev->power.next_event != KTIME_MAX &&
+ !ktime_before(pdd->dev->power.next_event, now)) {
+ next_wakeup = READ_ONCE(pdd->dev->power.next_event);
+ if (ktime_before(next_wakeup, domain_wakeup))
+ domain_wakeup = next_wakeup;
+ }
+ }
+
+ /* Then find the earliest wakeup of from all the child domains */
+ list_for_each_entry(link, &genpd->parent_links, parent_node) {
+ struct generic_pm_domain *sd = link->child;
+
+ next_wakeup = sd->next_wakeup;
+ if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
+ if (ktime_before(next_wakeup, domain_wakeup))
+ domain_wakeup = next_wakeup;
+ }
+
+ genpd->next_wakeup = domain_wakeup;
+}
+
+static bool next_wakeup_allows_state(struct generic_pm_domain *genpd,
+ unsigned int state, ktime_t now)
+{
+ s64 idle_time_ns, min_sleep_ns;
+ ktime_t domain_wakeup = genpd->next_wakeup;
+
+ if (domain_wakeup == KTIME_MAX)
+ return true;
+
+ min_sleep_ns = genpd->states[state].power_off_latency_ns +
+ genpd->states[state].power_on_latency_ns +
+ genpd->states[state].residency_ns;
+
+ idle_time_ns = ktime_to_ns(ktime_sub(domain_wakeup, now));
+ if (idle_time_ns < min_sleep_ns)
+ return false;
+
+ return true;
+}
+
static bool __default_power_down_ok(struct dev_pm_domain *pd,
unsigned int state)
{
@@ -210,6 +260,29 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
{
struct generic_pm_domain *genpd = pd_to_genpd(pd);
struct gpd_link *link;
+ unsigned int state_idx;
+ ktime_t now = ktime_get();
+
+ /*
+ * Find the next wakeup from devices that can determine their own wakeup
+ * to find when the domain would wakeup and do it for every device down
+ * the hierarchy. It is not worth while to sleep if the state's residency
+ * cannot be met.
+ */
+ update_domain_next_wakeup(genpd, now);
+
+ /* Let's find out what domain idle state, the devices prefer */
+ genpd->state_idx = state_idx = genpd->state_count - 1;
+ while (!next_wakeup_allows_state(genpd, state_idx, now)) {
+ if (!state_idx) {
+ genpd->cached_power_down_ok = false;
+ return false;
+ }
+ state_idx--;
+ }
+
+ genpd->max_off_time_changed =
+ (state_idx == genpd->cached_power_down_state_idx);
if (!genpd->max_off_time_changed) {
genpd->state_idx = genpd->cached_power_down_state_idx;
@@ -228,18 +301,20 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
genpd->max_off_time_ns = -1;
genpd->max_off_time_changed = false;
genpd->cached_power_down_ok = true;
- genpd->state_idx = genpd->state_count - 1;
- /* Find a state to power down to, starting from the deepest. */
- while (!__default_power_down_ok(pd, genpd->state_idx)) {
- if (genpd->state_idx == 0) {
+ /* Find a state to power down to, starting from the state
+ * determined by the next wakeup.
+ */
+ while (!__default_power_down_ok(pd, state_idx)) {
+ if (state_idx == 0) {
genpd->cached_power_down_ok = false;
break;
}
- genpd->state_idx--;
+ state_idx--;
}
- genpd->cached_power_down_state_idx = genpd->state_idx;
+ genpd->state_idx = state_idx;
+ genpd->cached_power_down_state_idx = state_idx;
return genpd->cached_power_down_ok;
}
@@ -119,6 +119,7 @@ struct generic_pm_domain {
unsigned int state);
struct gpd_dev_ops dev_ops;
s64 max_off_time_ns; /* Maximum allowed "suspended" time. */
+ ktime_t next_wakeup;
bool max_off_time_changed;
bool cached_power_down_ok;
bool cached_power_down_state_idx;
If the device's next event is known, determine if it is worthwhile entering a domain idle state. To find the next wakeup, traverse a domain for all child devices and find out the earliest wakeup value. A parent domain's next wakeup is the earliest of all its child devices and domains. The next wakeup is specified by devices in the domains before they devices are suspended. Update the domain governor logic to determine if it is worthwhile to enter an idle state based on the next wakeup for the domain along with other existing constraints. Signed-off-by: Lina Iyer <ilina@codeaurora.org> --- drivers/base/power/domain_governor.c | 87 ++++++++++++++++++++++++++-- include/linux/pm_domain.h | 1 + 2 files changed, 82 insertions(+), 6 deletions(-)