250 lines
6.5 KiB
C
250 lines
6.5 KiB
C
/*
|
|
* drivers/base/power/domain_governor.c - Governors for device PM domains.
|
|
*
|
|
* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
|
|
*
|
|
* This file is released under the GPLv2.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/pm_domain.h>
|
|
#include <linux/pm_qos.h>
|
|
#include <linux/hrtimer.h>
|
|
|
|
#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.
|
|
*/
|
|
static 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__);
|
|
|
|
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 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;
|
|
}
|
|
|
|
/**
|
|
* default_power_down_ok - Default generic PM domain power off governor routine.
|
|
* @pd: PM domain to check.
|
|
*
|
|
* This routine must be executed under the PM domain's lock.
|
|
*/
|
|
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_off_time_ns;
|
|
s64 off_on_time_ns;
|
|
|
|
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;
|
|
/*
|
|
* It doesn't make sense to remove power from the domain if saving
|
|
* the state of all devices in it and the power off/power on operations
|
|
* take too much time.
|
|
*
|
|
* All devices in this domain have been stopped already at this point.
|
|
*/
|
|
list_for_each_entry(pdd, &genpd->dev_list, list_node) {
|
|
if (pdd->dev->driver)
|
|
off_on_time_ns +=
|
|
to_gpd_data(pdd)->td.save_state_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->master_links, master_node) {
|
|
struct generic_pm_domain *sd = link->slave;
|
|
s64 sd_max_off_ns = sd->max_off_time_ns;
|
|
|
|
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;
|
|
|
|
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;
|
|
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;
|
|
|
|
/*
|
|
* constraint_ns cannot be negative here, because the device has
|
|
* been suspended.
|
|
*/
|
|
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;
|
|
|
|
/*
|
|
* 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->max_off_time_ns = min_off_time_ns - genpd->power_on_latency_ns;
|
|
return true;
|
|
}
|
|
|
|
static bool always_on_power_down_ok(struct dev_pm_domain *domain)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
#else /* !CONFIG_PM_RUNTIME */
|
|
|
|
static inline bool default_stop_ok(struct device *dev) { return false; }
|
|
|
|
#define default_power_down_ok NULL
|
|
#define always_on_power_down_ok NULL
|
|
|
|
#endif /* !CONFIG_PM_RUNTIME */
|
|
|
|
struct dev_power_governor simple_qos_governor = {
|
|
.stop_ok = default_stop_ok,
|
|
.power_down_ok = default_power_down_ok,
|
|
};
|
|
|
|
/**
|
|
* pm_genpd_gov_always_on - A governor implementing an always-on policy
|
|
*/
|
|
struct dev_power_governor pm_domain_always_on_gov = {
|
|
.power_down_ok = always_on_power_down_ok,
|
|
.stop_ok = default_stop_ok,
|
|
};
|