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-rw-r--r--drivers/pmdomain/governor.c418
1 files changed, 418 insertions, 0 deletions
diff --git a/drivers/pmdomain/governor.c b/drivers/pmdomain/governor.c
new file mode 100644
index 0000000000..d1a10eeebd
--- /dev/null
+++ b/drivers/pmdomain/governor.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drivers/base/power/domain_governor.c - Governors for device PM domains.
+ *
+ * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
+ */
+#include <linux/kernel.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_qos.h>
+#include <linux/hrtimer.h>
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/ktime.h>
+
+static int dev_update_qos_constraint(struct device *dev, void *data)
+{
+ s64 *constraint_ns_p = data;
+ s64 constraint_ns;
+
+ if (dev->power.subsys_data && dev->power.subsys_data->domain_data) {
+ struct gpd_timing_data *td = dev_gpd_data(dev)->td;
+
+ /*
+ * Only take suspend-time QoS constraints of devices into
+ * account, because constraints updated after the device has
+ * been suspended are not guaranteed to be taken into account
+ * anyway. In order for them to take effect, the device has to
+ * be resumed and suspended again.
+ */
+ constraint_ns = td ? td->effective_constraint_ns :
+ PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
+ } else {
+ /*
+ * The child is not in a domain and there's no info on its
+ * suspend/resume latencies, so assume them to be negligible and
+ * take its current PM QoS constraint (that's the only thing
+ * known at this point anyway).
+ */
+ constraint_ns = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
+ constraint_ns *= NSEC_PER_USEC;
+ }
+
+ if (constraint_ns < *constraint_ns_p)
+ *constraint_ns_p = constraint_ns;
+
+ return 0;
+}
+
+/**
+ * default_suspend_ok - Default PM domain governor routine to suspend devices.
+ * @dev: Device to check.
+ *
+ * Returns: true if OK to suspend, false if not OK to suspend
+ */
+static bool default_suspend_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__);
+
+ spin_lock_irqsave(&dev->power.lock, flags);
+
+ if (!td->constraint_changed) {
+ bool ret = td->cached_suspend_ok;
+
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+ return ret;
+ }
+ td->constraint_changed = false;
+ td->cached_suspend_ok = false;
+ td->effective_constraint_ns = 0;
+ constraint_ns = __dev_pm_qos_resume_latency(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 == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS) {
+ /* "No restriction", so the device is allowed to suspend. */
+ td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
+ td->cached_suspend_ok = true;
+ } else if (constraint_ns == 0) {
+ /*
+ * This triggers if one of the children that don't belong to a
+ * domain has a zero PM QoS constraint and it's better not to
+ * suspend then. effective_constraint_ns is zero already and
+ * cached_suspend_ok is false, so bail out.
+ */
+ return false;
+ } else {
+ constraint_ns -= td->suspend_latency_ns +
+ td->resume_latency_ns;
+ /*
+ * effective_constraint_ns is zero already and cached_suspend_ok
+ * is false, so if the computed value is not positive, return
+ * right away.
+ */
+ if (constraint_ns <= 0)
+ return false;
+
+ td->effective_constraint_ns = constraint_ns;
+ td->cached_suspend_ok = true;
+ }
+
+ /*
+ * The children have been suspended already, so we don't need to take
+ * their suspend latencies into account here.
+ */
+ 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;
+
+ if (!(genpd->flags & GENPD_FLAG_MIN_RESIDENCY))
+ return;
+
+ /*
+ * Devices that have a predictable wakeup pattern, may specify
+ * their next wakeup. Let's find the next wakeup from all the
+ * devices attached to this domain and from all the sub-domains.
+ * It is possible that component's a next wakeup may have become
+ * stale when we read that here. We will ignore to ensure the domain
+ * is able to enter its optimal idle state.
+ */
+ list_for_each_entry(pdd, &genpd->dev_list, list_node) {
+ next_wakeup = to_gpd_data(pdd)->td->next_wakeup;
+ if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
+ if (ktime_before(next_wakeup, domain_wakeup))
+ domain_wakeup = next_wakeup;
+ }
+
+ list_for_each_entry(link, &genpd->parent_links, parent_node) {
+ struct genpd_governor_data *cgd = link->child->gd;
+
+ next_wakeup = cgd ? cgd->next_wakeup : KTIME_MAX;
+ if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
+ if (ktime_before(next_wakeup, domain_wakeup))
+ domain_wakeup = next_wakeup;
+ }
+
+ genpd->gd->next_wakeup = domain_wakeup;
+}
+
+static bool next_wakeup_allows_state(struct generic_pm_domain *genpd,
+ unsigned int state, ktime_t now)
+{
+ ktime_t domain_wakeup = genpd->gd->next_wakeup;
+ s64 idle_time_ns, min_sleep_ns;
+
+ min_sleep_ns = genpd->states[state].power_off_latency_ns +
+ genpd->states[state].residency_ns;
+
+ idle_time_ns = ktime_to_ns(ktime_sub(domain_wakeup, now));
+
+ return idle_time_ns >= min_sleep_ns;
+}
+
+static bool __default_power_down_ok(struct dev_pm_domain *pd,
+ unsigned int state)
+{
+ struct generic_pm_domain *genpd = pd_to_genpd(pd);
+ struct gpd_link *link;
+ struct pm_domain_data *pdd;
+ s64 min_off_time_ns;
+ s64 off_on_time_ns;
+
+ off_on_time_ns = genpd->states[state].power_off_latency_ns +
+ genpd->states[state].power_on_latency_ns;
+
+ min_off_time_ns = -1;
+ /*
+ * Check if subdomains can be off for enough time.
+ *
+ * All subdomains have been powered off already at this point.
+ */
+ list_for_each_entry(link, &genpd->parent_links, parent_node) {
+ struct genpd_governor_data *cgd = link->child->gd;
+
+ s64 sd_max_off_ns = cgd ? cgd->max_off_time_ns : -1;
+
+ if (sd_max_off_ns < 0)
+ continue;
+
+ /*
+ * 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
+ * it will have to wait worst case).
+ */
+ 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.
+ */
+ list_for_each_entry(pdd, &genpd->dev_list, list_node) {
+ struct gpd_timing_data *td;
+ s64 constraint_ns;
+
+ /*
+ * 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;
+ constraint_ns = td->effective_constraint_ns;
+ /*
+ * Zero means "no suspend at all" and this runs only when all
+ * devices in the domain are suspended, so it must be positive.
+ */
+ if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS)
+ continue;
+
+ 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;
+ }
+
+ /*
+ * 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.
+ */
+ if (min_off_time_ns < 0)
+ return true;
+
+ /*
+ * 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.
+ */
+ genpd->gd->max_off_time_ns = min_off_time_ns -
+ genpd->states[state].power_on_latency_ns;
+ return true;
+}
+
+/**
+ * _default_power_down_ok - Default generic PM domain power off governor routine.
+ * @pd: PM domain to check.
+ * @now: current ktime.
+ *
+ * This routine must be executed under the PM domain's lock.
+ *
+ * Returns: true if OK to power down, false if not OK to power down
+ */
+static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
+{
+ struct generic_pm_domain *genpd = pd_to_genpd(pd);
+ struct genpd_governor_data *gd = genpd->gd;
+ int state_idx = genpd->state_count - 1;
+ struct gpd_link *link;
+
+ /*
+ * 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);
+ if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (gd->next_wakeup != KTIME_MAX)) {
+ /* Let's find out the deepest domain idle state, the devices prefer */
+ while (state_idx >= 0) {
+ if (next_wakeup_allows_state(genpd, state_idx, now)) {
+ gd->max_off_time_changed = true;
+ break;
+ }
+ state_idx--;
+ }
+
+ if (state_idx < 0) {
+ state_idx = 0;
+ gd->cached_power_down_ok = false;
+ goto done;
+ }
+ }
+
+ if (!gd->max_off_time_changed) {
+ genpd->state_idx = gd->cached_power_down_state_idx;
+ return gd->cached_power_down_ok;
+ }
+
+ /*
+ * We have to invalidate the cached results for the parents, so
+ * use the observation that default_power_down_ok() is not
+ * going to be called for any parent until this instance
+ * returns.
+ */
+ list_for_each_entry(link, &genpd->child_links, child_node) {
+ struct genpd_governor_data *pgd = link->parent->gd;
+
+ if (pgd)
+ pgd->max_off_time_changed = true;
+ }
+
+ gd->max_off_time_ns = -1;
+ gd->max_off_time_changed = false;
+ gd->cached_power_down_ok = true;
+
+ /*
+ * 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) {
+ gd->cached_power_down_ok = false;
+ break;
+ }
+ state_idx--;
+ }
+
+done:
+ genpd->state_idx = state_idx;
+ gd->cached_power_down_state_idx = genpd->state_idx;
+ return gd->cached_power_down_ok;
+}
+
+static bool default_power_down_ok(struct dev_pm_domain *pd)
+{
+ return _default_power_down_ok(pd, ktime_get());
+}
+
+#ifdef CONFIG_CPU_IDLE
+static bool cpu_power_down_ok(struct dev_pm_domain *pd)
+{
+ struct generic_pm_domain *genpd = pd_to_genpd(pd);
+ struct cpuidle_device *dev;
+ ktime_t domain_wakeup, next_hrtimer;
+ ktime_t now = ktime_get();
+ s64 idle_duration_ns;
+ int cpu, i;
+
+ /* Validate dev PM QoS constraints. */
+ if (!_default_power_down_ok(pd, now))
+ return false;
+
+ if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))
+ return true;
+
+ /*
+ * Find the next wakeup for any of the online CPUs within the PM domain
+ * and its subdomains. Note, we only need the genpd->cpus, as it already
+ * contains a mask of all CPUs from subdomains.
+ */
+ domain_wakeup = ktime_set(KTIME_SEC_MAX, 0);
+ for_each_cpu_and(cpu, genpd->cpus, cpu_online_mask) {
+ dev = per_cpu(cpuidle_devices, cpu);
+ if (dev) {
+ next_hrtimer = READ_ONCE(dev->next_hrtimer);
+ if (ktime_before(next_hrtimer, domain_wakeup))
+ domain_wakeup = next_hrtimer;
+ }
+ }
+
+ /* The minimum idle duration is from now - until the next wakeup. */
+ idle_duration_ns = ktime_to_ns(ktime_sub(domain_wakeup, now));
+ if (idle_duration_ns <= 0)
+ return false;
+
+ /* Store the next domain_wakeup to allow consumers to use it. */
+ genpd->gd->next_hrtimer = domain_wakeup;
+
+ /*
+ * Find the deepest idle state that has its residency value satisfied
+ * and by also taking into account the power off latency for the state.
+ * Start at the state picked by the dev PM QoS constraint validation.
+ */
+ i = genpd->state_idx;
+ do {
+ if (idle_duration_ns >= (genpd->states[i].residency_ns +
+ genpd->states[i].power_off_latency_ns)) {
+ genpd->state_idx = i;
+ return true;
+ }
+ } while (--i >= 0);
+
+ return false;
+}
+
+struct dev_power_governor pm_domain_cpu_gov = {
+ .suspend_ok = default_suspend_ok,
+ .power_down_ok = cpu_power_down_ok,
+};
+#endif
+
+struct dev_power_governor simple_qos_governor = {
+ .suspend_ok = default_suspend_ok,
+ .power_down_ok = default_power_down_ok,
+};
+
+/*
+ * pm_domain_always_on_gov - A governor implementing an always-on policy
+ */
+struct dev_power_governor pm_domain_always_on_gov = {
+ .suspend_ok = default_suspend_ok,
+};