summaryrefslogtreecommitdiff
path: root/include/linux/pm_domain.h
AgeCommit message (Collapse)Author
2011-07-14ARM / shmobile: Use genpd_queue_power_off_work()Rafael J. Wysocki
Make pd_power_down_a3rv() use genpd_queue_power_off_work() to queue up the powering off of the A4LC domain to avoid queuing it up when it is pending. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@opensource.se>
2011-07-13PM / Domains: Introduce function to power off all unused PM domainsRafael J. Wysocki
Add a new function pm_genpd_poweroff_unused() queuing up the execution of pm_genpd_poweroff() for every initialized generic PM domain. Calling it will cause every generic PM domain without devices in use to be powered off. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@opensource.se>
2011-07-12PM / Domains: Allow callbacks to execute all runtime PM helpersRafael J. Wysocki
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>
2011-07-12PM / Domains: Do not execute device callbacks under locksRafael J. Wysocki
Currently, the .start_device() and .stop_device() callbacks from struct generic_pm_domain() as well as the device drivers' runtime PM callbacks used by the generic PM domains code are executed under the generic PM domain lock. This, unfortunately, is prone to deadlocks, for example if a device and its parent are boths members of the same PM domain. For this reason, it would be better if the PM domains code didn't execute device callbacks under the lock. Rework the locking in the generic PM domains code so that the lock is dropped for the execution of device callbacks. To this end, introduce PM domains states reflecting the current status of a PM domain and such that the PM domain lock cannot be acquired if the status is GPD_STATE_BUSY. Make threads attempting to acquire a PM domain's lock wait until the status changes to either GPD_STATE_ACTIVE or GPD_STATE_POWER_OFF. This change by itself doesn't fix the deadlock problem mentioned above, but the mechanism introduced by it will be used for for this purpose by a subsequent patch. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-07-10PM / Domains: Export pm_genpd_poweron() in headerMagnus Damm
Allow SoC-specific code to call pm_genpd_poweron(). Signed-off-by: Magnus Damm <damm@opensource.se> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-07-02PM / Domains: Wakeup devices support for system sleep transitionsRafael J. Wysocki
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>
2011-07-02PM / Domains: System-wide transitions support for generic domains (v5)Rafael J. Wysocki
Make generic PM domains support system-wide power transitions (system suspend and hibernation). Add suspend, resume, freeze, thaw, poweroff and restore callbacks to be associated with struct generic_pm_domain objects and make pm_genpd_init() use them as appropriate. The new callbacks do nothing for devices belonging to power domains that were powered down at run time (before the transition). For the other devices the action carried out depends on the type of the transition. During system suspend the power domain .suspend() callback executes pm_generic_suspend() for the device, while the PM domain .suspend_noirq() callback runs pm_generic_suspend_noirq() for it, stops it and eventually removes power from the PM domain it belongs to (after all devices in the domain have been stopped and its subdomains have been powered off). During system resume the PM domain .resume_noirq() callback restores power to the PM domain (when executed for it first time), starts the device and executes pm_generic_resume_noirq() for it, while the .resume() callback executes pm_generic_resume() for the device. Finally, the .complete() callback executes pm_runtime_idle() for the device which should put it back into the suspended state if its runtime PM usage count is equal to zero at that time. The actions carried out during hibernation and resume from it are analogous to the ones described above. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Kevin Hilman <khilman@ti.com>
2011-07-02PM / Domains: Support for generic I/O PM domains (v8)Rafael J. Wysocki
Introduce common headers, helper functions and callbacks allowing platforms to use simple generic power domains for runtime power management. Introduce struct generic_pm_domain to be used for representing power domains that each contain a number of devices and may be parent domains or subdomains with respect to other power domains. Among other things, this structure includes callbacks to be provided by platforms for performing specific tasks related to power management (i.e. ->stop_device() may disable a device's clocks, while ->start_device() may enable them, ->power_off() is supposed to remove power from the entire power domain and ->power_on() is supposed to restore it). Introduce functions that can be used as power domain runtime PM callbacks, pm_genpd_runtime_suspend() and pm_genpd_runtime_resume(), as well as helper functions for the initialization of a power domain represented by a struct generic_power_domain object, adding a device to or removing a device from it and adding or removing subdomains. Introduce configuration option CONFIG_PM_GENERIC_DOMAINS to be selected by the platforms that want to use the new code. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Reviewed-by: Kevin Hilman <khilman@ti.com>