2011-07-02 00:12:45 +04:00
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/*
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* pm_domain.h - Definitions and headers related to device power 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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#ifndef _LINUX_PM_DOMAIN_H
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#define _LINUX_PM_DOMAIN_H
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#include <linux/device.h>
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2011-07-12 02:39:29 +04:00
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enum gpd_status {
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GPD_STATE_ACTIVE = 0, /* PM domain is active */
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GPD_STATE_BUSY, /* Something is happening to the PM domain */
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PM / Domains: Allow callbacks to execute all runtime PM helpers
A deadlock may occur if one of the PM domains' .start_device() or
.stop_device() callbacks or a device driver's .runtime_suspend() or
.runtime_resume() callback executed by the core generic PM domain
code uses a "wrong" runtime PM helper function. This happens, for
example, if .runtime_resume() from one device's driver calls
pm_runtime_resume() for another device in the same PM domain.
A similar situation may take place if a device's parent is in the
same PM domain, in which case the runtime PM framework may execute
pm_genpd_runtime_resume() automatically for the parent (if it is
suspended at the moment). This, of course, is undesirable, so
the generic PM domains code should be modified to prevent it from
happening.
The runtime PM framework guarantees that pm_genpd_runtime_suspend()
and pm_genpd_runtime_resume() won't be executed in parallel for
the same device, so the generic PM domains code need not worry
about those cases. Still, it needs to prevent the other possible
race conditions between pm_genpd_runtime_suspend(),
pm_genpd_runtime_resume(), pm_genpd_poweron() and pm_genpd_poweroff()
from happening and it needs to avoid deadlocks at the same time.
To this end, modify the generic PM domains code to relax
synchronization rules so that:
* pm_genpd_poweron() doesn't wait for the PM domain status to
change from GPD_STATE_BUSY. If it finds that the status is
not GPD_STATE_POWER_OFF, it returns without powering the domain on
(it may modify the status depending on the circumstances).
* pm_genpd_poweroff() returns as soon as it finds that the PM
domain's status changed from GPD_STATE_BUSY after it's released
the PM domain's lock.
* pm_genpd_runtime_suspend() doesn't wait for the PM domain status
to change from GPD_STATE_BUSY after executing the domain's
.stop_device() callback and executes pm_genpd_poweroff() only
if pm_genpd_runtime_resume() is not executed in parallel.
* pm_genpd_runtime_resume() doesn't wait for the PM domain status
to change from GPD_STATE_BUSY after executing pm_genpd_poweron()
and sets the domain's status to GPD_STATE_BUSY and increments its
counter of resuming devices (introduced by this change) immediately
after acquiring the lock. The counter of resuming devices is then
decremented after executing __pm_genpd_runtime_resume() for the
device and the domain's status is reset to GPD_STATE_ACTIVE (unless
there are more resuming devices in the domain, in which case the
status remains GPD_STATE_BUSY).
This way, for example, if a device driver's .runtime_resume()
callback executes pm_runtime_resume() for another device in the same
PM domain, pm_genpd_poweron() called by pm_genpd_runtime_resume()
invoked by the runtime PM framework will not block and it will see
that there's nothing to do for it. Next, the PM domain's lock will
be acquired without waiting for its status to change from
GPD_STATE_BUSY and the device driver's .runtime_resume() callback
will be executed. In turn, if pm_runtime_suspend() is executed by
one device driver's .runtime_resume() callback for another device in
the same PM domain, pm_genpd_poweroff() executed by
pm_genpd_runtime_suspend() invoked by the runtime PM framework as a
result will notice that one of the devices in the domain is being
resumed, so it will return immediately.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-07-12 02:39:36 +04:00
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GPD_STATE_REPEAT, /* Power off in progress, to be repeated */
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2011-07-12 02:39:29 +04:00
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GPD_STATE_POWER_OFF, /* PM domain is off */
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};
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2011-07-02 00:13:19 +04:00
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2011-07-02 00:12:45 +04:00
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struct dev_power_governor {
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bool (*power_down_ok)(struct dev_pm_domain *domain);
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};
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struct generic_pm_domain {
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struct dev_pm_domain domain; /* PM domain operations */
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struct list_head sd_node; /* Node in the parent's subdomain list */
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struct generic_pm_domain *parent; /* Parent PM domain */
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struct list_head sd_list; /* List of dubdomains */
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struct list_head dev_list; /* List of devices */
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struct mutex lock;
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struct dev_power_governor *gov;
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struct work_struct power_off_work;
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unsigned int in_progress; /* Number of devices being suspended now */
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unsigned int sd_count; /* Number of subdomains with power "on" */
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2011-07-12 02:39:29 +04:00
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enum gpd_status status; /* Current state of the domain */
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wait_queue_head_t status_wait_queue;
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PM / Domains: Allow callbacks to execute all runtime PM helpers
A deadlock may occur if one of the PM domains' .start_device() or
.stop_device() callbacks or a device driver's .runtime_suspend() or
.runtime_resume() callback executed by the core generic PM domain
code uses a "wrong" runtime PM helper function. This happens, for
example, if .runtime_resume() from one device's driver calls
pm_runtime_resume() for another device in the same PM domain.
A similar situation may take place if a device's parent is in the
same PM domain, in which case the runtime PM framework may execute
pm_genpd_runtime_resume() automatically for the parent (if it is
suspended at the moment). This, of course, is undesirable, so
the generic PM domains code should be modified to prevent it from
happening.
The runtime PM framework guarantees that pm_genpd_runtime_suspend()
and pm_genpd_runtime_resume() won't be executed in parallel for
the same device, so the generic PM domains code need not worry
about those cases. Still, it needs to prevent the other possible
race conditions between pm_genpd_runtime_suspend(),
pm_genpd_runtime_resume(), pm_genpd_poweron() and pm_genpd_poweroff()
from happening and it needs to avoid deadlocks at the same time.
To this end, modify the generic PM domains code to relax
synchronization rules so that:
* pm_genpd_poweron() doesn't wait for the PM domain status to
change from GPD_STATE_BUSY. If it finds that the status is
not GPD_STATE_POWER_OFF, it returns without powering the domain on
(it may modify the status depending on the circumstances).
* pm_genpd_poweroff() returns as soon as it finds that the PM
domain's status changed from GPD_STATE_BUSY after it's released
the PM domain's lock.
* pm_genpd_runtime_suspend() doesn't wait for the PM domain status
to change from GPD_STATE_BUSY after executing the domain's
.stop_device() callback and executes pm_genpd_poweroff() only
if pm_genpd_runtime_resume() is not executed in parallel.
* pm_genpd_runtime_resume() doesn't wait for the PM domain status
to change from GPD_STATE_BUSY after executing pm_genpd_poweron()
and sets the domain's status to GPD_STATE_BUSY and increments its
counter of resuming devices (introduced by this change) immediately
after acquiring the lock. The counter of resuming devices is then
decremented after executing __pm_genpd_runtime_resume() for the
device and the domain's status is reset to GPD_STATE_ACTIVE (unless
there are more resuming devices in the domain, in which case the
status remains GPD_STATE_BUSY).
This way, for example, if a device driver's .runtime_resume()
callback executes pm_runtime_resume() for another device in the same
PM domain, pm_genpd_poweron() called by pm_genpd_runtime_resume()
invoked by the runtime PM framework will not block and it will see
that there's nothing to do for it. Next, the PM domain's lock will
be acquired without waiting for its status to change from
GPD_STATE_BUSY and the device driver's .runtime_resume() callback
will be executed. In turn, if pm_runtime_suspend() is executed by
one device driver's .runtime_resume() callback for another device in
the same PM domain, pm_genpd_poweroff() executed by
pm_genpd_runtime_suspend() invoked by the runtime PM framework as a
result will notice that one of the devices in the domain is being
resumed, so it will return immediately.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-07-12 02:39:36 +04:00
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struct task_struct *poweroff_task; /* Powering off task */
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unsigned int resume_count; /* Number of devices being resumed */
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2011-07-02 00:13:19 +04:00
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unsigned int device_count; /* Number of devices */
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unsigned int suspended_count; /* System suspend device counter */
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unsigned int prepared_count; /* Suspend counter of prepared devices */
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bool suspend_power_off; /* Power status before system suspend */
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2011-07-02 00:12:45 +04:00
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int (*power_off)(struct generic_pm_domain *domain);
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int (*power_on)(struct generic_pm_domain *domain);
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int (*start_device)(struct device *dev);
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int (*stop_device)(struct device *dev);
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PM / Domains: Wakeup devices support for system sleep transitions
There is the problem how to handle devices set up to wake up the
system from sleep states during system-wide power transitions.
In some cases, those devices can be turned off entirely, because the
wakeup signals will be generated on their behalf anyway. In some
other cases, they will generate wakeup signals if their clocks are
stopped, but only if power is not removed from them. Finally, in
some cases, they can only generate wakeup signals if power is not
removed from them and their clocks are enabled.
To allow platform-specific code to decide whether or not to put
wakeup devices (and their PM domains) into low-power state during
system-wide transitions, such as system suspend, introduce a new
generic PM domain callback, .active_wakeup(), that will be used
during the "noirq" phase of system suspend and hibernation (after
image creation) to decide what to do with wakeup devices.
Specifically, if this callback is present and returns "true", the
generic PM domain code will not execute .stop_device() for the
given wakeup device and its PM domain won't be powered off.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
2011-07-02 00:13:29 +04:00
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bool (*active_wakeup)(struct device *dev);
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2011-07-02 00:12:45 +04:00
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};
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2011-07-02 00:13:19 +04:00
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static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)
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{
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return container_of(pd, struct generic_pm_domain, domain);
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}
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2011-07-02 00:12:45 +04:00
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struct dev_list_entry {
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struct list_head node;
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struct device *dev;
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bool need_restore;
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};
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#ifdef CONFIG_PM_GENERIC_DOMAINS
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extern int pm_genpd_add_device(struct generic_pm_domain *genpd,
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struct device *dev);
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extern int pm_genpd_remove_device(struct generic_pm_domain *genpd,
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struct device *dev);
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extern int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *new_subdomain);
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extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *target);
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extern void pm_genpd_init(struct generic_pm_domain *genpd,
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struct dev_power_governor *gov, bool is_off);
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2011-07-10 12:39:14 +04:00
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extern int pm_genpd_poweron(struct generic_pm_domain *genpd);
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2011-07-02 00:12:45 +04:00
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#else
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static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
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struct device *dev)
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{
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return -ENOSYS;
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}
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static inline int pm_genpd_remove_device(struct generic_pm_domain *genpd,
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struct device *dev)
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{
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return -ENOSYS;
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}
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static inline int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *new_sd)
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{
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return -ENOSYS;
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}
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static inline int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *target)
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{
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return -ENOSYS;
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}
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static inline void pm_genpd_init(struct generic_pm_domain *genpd,
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struct dev_power_governor *gov, bool is_off) {}
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2011-07-10 12:39:14 +04:00
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static inline int pm_genpd_poweron(struct generic_pm_domain *genpd)
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{
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return -ENOSYS;
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}
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2011-07-02 00:12:45 +04:00
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#endif
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#endif /* _LINUX_PM_DOMAIN_H */
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