![Rafael J. Wysocki](/assets/img/avatar_default.png)
The governor functions in drivers/base/power/domain_governor.c are only used if CONFIG_PM_RUNTIME is set and they refer to data structures that are only present in that case. For this reason, they shouldn't be compiled at all when CONFIG_PM_RUNTIME is not set. Reported-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
171 lines
4.5 KiB
C
171 lines
4.5 KiB
C
/*
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* drivers/base/power/domain_governor.c - Governors for device PM domains.
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*
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* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/pm_domain.h>
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#include <linux/pm_qos.h>
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#include <linux/hrtimer.h>
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#ifdef CONFIG_PM_RUNTIME
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/**
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* default_stop_ok - Default PM domain governor routine for stopping devices.
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* @dev: Device to check.
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*/
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bool default_stop_ok(struct device *dev)
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{
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struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
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dev_dbg(dev, "%s()\n", __func__);
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if (dev->power.max_time_suspended_ns < 0 || td->break_even_ns == 0)
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return true;
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return td->stop_latency_ns + td->start_latency_ns < td->break_even_ns
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&& td->break_even_ns < dev->power.max_time_suspended_ns;
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}
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/**
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* default_power_down_ok - Default generic PM domain power off governor routine.
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* @pd: PM domain to check.
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*
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* This routine must be executed under the PM domain's lock.
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*/
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static bool default_power_down_ok(struct dev_pm_domain *pd)
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{
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struct generic_pm_domain *genpd = pd_to_genpd(pd);
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struct gpd_link *link;
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struct pm_domain_data *pdd;
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s64 min_dev_off_time_ns;
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s64 off_on_time_ns;
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ktime_t time_now = ktime_get();
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off_on_time_ns = genpd->power_off_latency_ns +
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genpd->power_on_latency_ns;
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/*
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* It doesn't make sense to remove power from the domain if saving
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* the state of all devices in it and the power off/power on operations
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* take too much time.
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*
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* All devices in this domain have been stopped already at this point.
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*/
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list_for_each_entry(pdd, &genpd->dev_list, list_node) {
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if (pdd->dev->driver)
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off_on_time_ns +=
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to_gpd_data(pdd)->td.save_state_latency_ns;
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}
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/*
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* Check if subdomains can be off for enough time.
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*
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* All subdomains have been powered off already at this point.
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*/
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list_for_each_entry(link, &genpd->master_links, master_node) {
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struct generic_pm_domain *sd = link->slave;
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s64 sd_max_off_ns = sd->max_off_time_ns;
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if (sd_max_off_ns < 0)
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continue;
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sd_max_off_ns -= ktime_to_ns(ktime_sub(time_now,
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sd->power_off_time));
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/*
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* Check if the subdomain is allowed to be off long enough for
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* the current domain to turn off and on (that's how much time
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* it will have to wait worst case).
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*/
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if (sd_max_off_ns <= off_on_time_ns)
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return false;
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}
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/*
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* Check if the devices in the domain can be off enough time.
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*/
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min_dev_off_time_ns = -1;
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list_for_each_entry(pdd, &genpd->dev_list, list_node) {
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struct gpd_timing_data *td;
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struct device *dev = pdd->dev;
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s64 dev_off_time_ns;
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if (!dev->driver || dev->power.max_time_suspended_ns < 0)
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continue;
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td = &to_gpd_data(pdd)->td;
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dev_off_time_ns = dev->power.max_time_suspended_ns -
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(td->start_latency_ns + td->restore_state_latency_ns +
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ktime_to_ns(ktime_sub(time_now,
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dev->power.suspend_time)));
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if (dev_off_time_ns <= off_on_time_ns)
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return false;
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if (min_dev_off_time_ns > dev_off_time_ns
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|| min_dev_off_time_ns < 0)
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min_dev_off_time_ns = dev_off_time_ns;
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}
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if (min_dev_off_time_ns < 0) {
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/*
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* There are no latency constraints, so the domain can spend
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* arbitrary time in the "off" state.
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*/
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genpd->max_off_time_ns = -1;
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return true;
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}
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/*
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* The difference between the computed minimum delta and the time needed
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* to turn the domain on is the maximum theoretical time this domain can
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* spend in the "off" state.
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*/
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min_dev_off_time_ns -= genpd->power_on_latency_ns;
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/*
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* If the difference between the computed minimum delta and the time
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* needed to turn the domain off and back on on is smaller than the
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* domain's power break even time, removing power from the domain is not
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* worth it.
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*/
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if (genpd->break_even_ns >
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min_dev_off_time_ns - genpd->power_off_latency_ns)
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return false;
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genpd->max_off_time_ns = min_dev_off_time_ns;
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return true;
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}
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static bool always_on_power_down_ok(struct dev_pm_domain *domain)
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{
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return false;
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}
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#else /* !CONFIG_PM_RUNTIME */
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bool default_stop_ok(struct device *dev)
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{
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return false;
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}
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#define default_power_down_ok NULL
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#define always_on_power_down_ok NULL
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#endif /* !CONFIG_PM_RUNTIME */
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struct dev_power_governor simple_qos_governor = {
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.stop_ok = default_stop_ok,
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.power_down_ok = default_power_down_ok,
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};
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/**
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* pm_genpd_gov_always_on - A governor implementing an always-on policy
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*/
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struct dev_power_governor pm_domain_always_on_gov = {
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.power_down_ok = always_on_power_down_ok,
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.stop_ok = default_stop_ok,
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};
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