diff options
Diffstat (limited to 'drivers/base/power/domain_governor.c')
-rw-r--r-- | drivers/base/power/domain_governor.c | 166 |
1 files changed, 125 insertions, 41 deletions
diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c index 66a265bf586..28dee3053f1 100644 --- a/drivers/base/power/domain_governor.c +++ b/drivers/base/power/domain_governor.c @@ -14,6 +14,31 @@ #ifdef CONFIG_PM_RUNTIME +static int dev_update_qos_constraint(struct device *dev, void *data) +{ + s64 *constraint_ns_p = data; + s32 constraint_ns = -1; + + if (dev->power.subsys_data && dev->power.subsys_data->domain_data) + constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns; + + if (constraint_ns < 0) { + constraint_ns = dev_pm_qos_read_value(dev); + constraint_ns *= NSEC_PER_USEC; + } + if (constraint_ns == 0) + return 0; + + /* + * constraint_ns cannot be negative here, because the device has been + * suspended. + */ + if (constraint_ns < *constraint_ns_p || *constraint_ns_p == 0) + *constraint_ns_p = constraint_ns; + + return 0; +} + /** * default_stop_ok - Default PM domain governor routine for stopping devices. * @dev: Device to check. @@ -21,14 +46,52 @@ 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__); - if (dev->power.max_time_suspended_ns < 0 || td->break_even_ns == 0) - return true; + spin_lock_irqsave(&dev->power.lock, flags); + + if (!td->constraint_changed) { + bool ret = td->cached_stop_ok; - return td->stop_latency_ns + td->start_latency_ns < td->break_even_ns - && td->break_even_ns < dev->power.max_time_suspended_ns; + 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 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, + dev_update_qos_constraint); + + if (constraint_ns > 0) { + constraint_ns -= td->start_latency_ns; + if (constraint_ns == 0) + 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 td->cached_stop_ok; } /** @@ -42,9 +105,27 @@ static bool default_power_down_ok(struct dev_pm_domain *pd) 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; @@ -61,6 +142,7 @@ static bool default_power_down_ok(struct dev_pm_domain *pd) to_gpd_data(pdd)->td.save_state_latency_ns; } + min_off_time_ns = -1; /* * Check if subdomains can be off for enough time. * @@ -73,8 +155,6 @@ static bool default_power_down_ok(struct dev_pm_domain *pd) 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 @@ -82,60 +162,64 @@ static bool default_power_down_ok(struct dev_pm_domain *pd) */ 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; } |