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path: root/include/linux/pm_domain.h
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2011-12-09PM / Domains: Provide an always on power domain governorMark Brown
Since systems are likely to have power domains that can't be turned off for various reasons at least temporarily while implementing power domain support provide a default governor which will always refuse to power off the domain, saving platforms having to implement their own. Since the code is so tiny don't bother with a Kconfig symbol for it. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-12-06PM / Domains: Make it possible to assign names to generic PM domainsRafael J. Wysocki
Add a name member pointer to struct generic_pm_domain and use it in diagnostic messages regarding the domain power-off and power-on latencies. Update the ARM shmobile SH7372 code to assign names to the PM domains used by it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@opensource.se>
2011-12-01PM / Domains: fix compilation failure for CONFIG_PM_GENERIC_DOMAINS unsetGuennadi Liakhovetski
Fix the following compalitaion breakage: In file included from linux/drivers/sh/pm_runtime.c:15: linux/include/linux/pm_domain.h: In function 'dev_to_genpd': linux/include/linux/pm_domain.h:142: error: implicit declaration of function 'ERR_PTR' linux/include/linux/pm_domain.h:142: warning: return makes pointer from integer without a cast In file included from linux/include/linux/sh_clk.h:10, from linux/drivers/sh/pm_runtime.c:19: linux/include/linux/err.h: At top level: linux/include/linux/err.h:22: error: conflicting types for 'ERR_PTR' linux/include/linux/pm_domain.h:142: note: previous implicit declaration of 'ERR_PTR' was here make[3]: *** [drivers/sh/pm_runtime.o] Error 1 Reported-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-12-01PM / Domains: Add default power off governor function (v4)Rafael J. Wysocki
Add a function deciding whether or not a given PM domain should be powered off on the basis of the PM QoS constraints of devices belonging to it and their PM QoS timing data. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-12-01PM / Domains: Add device stop governor function (v4)Rafael J. Wysocki
Add a function deciding whether or not devices should be stopped in pm_genpd_runtime_suspend() depending on their PM QoS constraints and stop/start timing values. Make it possible to add information used by this function to device objects. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@opensource.se>
2011-12-01PM / Domains: Rework system suspend callback routines (v2)Rafael J. Wysocki
The current generic PM domains code attempts to use the generic system suspend operations along with the domains' device stop/start routines, which requires device drivers to assume that their system suspend/resume (and hibernation/restore) callbacks will always be used with generic PM domains. However, in theory, the same hardware may be used in devices that don't belong to any PM domain, in which case it would be necessary to add "fake" PM domains to satisfy the above assumption. Also, the domain the hardware belongs to may not be handled with the help of the generic code. To allow device drivers that may be used along with the generic PM domains code of more flexibility, add new device callbacks, .suspend(), .suspend_late(), .resume_early(), .resume(), .freeze(), .freeze_late(), .thaw_early(), and .thaw(), that can be supplied by the drivers in addition to their "standard" system suspend and hibernation callbacks. These new callbacks, if defined, will be used by the generic PM domains code for the handling of system suspend and hibernation instead of the "standard" ones. This will allow drivers to be designed to work with generic PM domains as well as without them. For backwards compatibility, introduce default implementations of the new callbacks for PM domains that will execute pm_generic_suspend(), pm_generic_suspend_noirq(), pm_generic_resume_noirq(), pm_generic_resume(), pm_generic_freeze(), pm_generic_freeze_noirq(), pm_generic_thaw_noirq(), and pm_generic_thaw(), respectively, for the given device if its driver doesn't define those callbacks. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-12-01PM / Domains: Introduce "save/restore state" device callbacksRafael J. Wysocki
The current PM domains code uses device drivers' .runtime_suspend() and .runtime_resume() callbacks as the "save device state" and "restore device state" operations, which may not be appropriate in general, because it forces drivers to assume that they always will be used with generic PM domains. However, in theory, the same hardware may be used in devices that don't belong to any PM domain, in which case it would be necessary to add "fake" PM domains to satisfy the above assumption. It also may be located in a PM domain that's not handled with the help of the generic code. To allow device drivers that may be used along with the generic PM domains code of more flexibility, introduce new device callbacks, .save_state() and .restore_state(), that can be supplied by the drivers in addition to their "standard" runtime PM callbacks. This will allow the drivers to be designed to work with generic PM domains as well as without them. For backwards compatibility, introduce default .save_state() and .restore_state() callback routines for PM domains that will execute a device driver's .runtime_suspend() and .runtime_resume() callbacks, respectively, for the given device if the driver doesn't provide its own implementations of .save_state() and .restore_state(). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-12-01PM / Domains: Make it possible to use per-device domain callbacksRafael J. Wysocki
The current generic PM domains code requires that the same .stop(), .start() and .active_wakeup() device callback routines be used for all devices in the given domain, which is inflexible and may not cover some specific use cases. For this reason, make it possible to use device specific .start()/.stop() and .active_wakeup() callback routines by adding corresponding callback pointers to struct generic_pm_domain_data. Add a new helper routine, pm_genpd_register_callbacks(), that can be used to populate the new per-device callback pointers. Modify the shmobile's power domains code to allow drivers to add their own code to be run during the device stop and start operations with the help of the new callback pointers. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Magnus Damm <damm@opensource.se>
2011-09-26PM / Domains: Split device PM domain data into base and need_restoreRafael J. Wysocki
The struct pm_domain_data data type is defined in such a way that adding new fields specific to the generic PM domains code will require include/linux/pm.h to be modified. As a result, data types used only by the generic PM domains code will be defined in two headers, although they all should be defined in pm_domain.h and pm.h will need to include more headers, which won't be very nice. For this reason change the definition of struct pm_subsys_data so that its domain_data member is a pointer, which will allow struct pm_domain_data to be subclassed by various PM domains implementations. Remove the need_restore member from struct pm_domain_data and make the generic PM domains code subclass it by adding the need_restore member to the new data type. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25PM / Domains: Preliminary support for devices with power.irq_safe setRafael J. Wysocki
The generic PM domains framework currently doesn't work with devices whose power.irq_safe flag is set, because runtime PM callbacks for such devices are run with interrupts disabled and the callbacks provided by the generic PM domains framework use domain mutexes and may sleep. However, such devices very well may belong to power domains on some systems, so the generic PM domains framework should take them into account. For this reason, modify the generic PM domains framework so that the domain .power_off() and .power_on() callbacks are never executed for a domain containing devices with power.irq_safe set, although the .stop_device() and .start_device() callbacks are still run for them. Additionally, introduce a flag allowing the creator of a struct generic_pm_domain object to indicate that its .stop_device() and .start_device() callbacks may be run in interrupt context (might_sleep_if() triggers if that flag is not set and one of those callbacks is run in interrupt context). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25PM / Domains: Use power.sybsys_data to reduce overheadRafael J. Wysocki
Currently pm_genpd_runtime_resume() has to walk the list of devices from the device's PM domain to find the corresponding device list object containing the need_restore field to check if the driver's .runtime_resume() callback should be executed for the device. This is suboptimal and can be simplified by using power.sybsys_data to store device information used by the generic PM domains code. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25PM / Domains: Rename GPD_STATE_WAIT_PARENT to GPD_STATE_WAIT_MASTERRafael J. Wysocki
Since it is now possible for a PM domain to have multiple masters instead of one parent, rename the "wait for parent" status to reflect the new situation. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25PM / Domains: Allow generic PM domains to have multiple mastersRafael J. Wysocki
Currently, for a given generic PM domain there may be only one parent domain (i.e. a PM domain it depends on). However, there is at least one real-life case in which there should be two parents (masters) for one PM domain (the A3RV domain on SH7372 turns out to depend on the A4LC domain and it depends on the A4R domain and the same time). For this reason, allow a PM domain to have multiple parents (masters) by introducing objects representing links between PM domains. The (logical) links between PM domains represent relationships in which one domain is a master (i.e. it is depended on) and another domain is a slave (i.e. it depends on the master) with the rule that the slave cannot be powered on if the master is not powered on and the master cannot be powered off if the slave is not powered off. Each struct generic_pm_domain object representing a PM domain has two lists of links, a list of links in which it is a master and a list of links in which it is a slave. The first of these lists replaces the list of subdomains and the second one is used in place of the parent pointer. Each link is represented by struct gpd_link object containing pointers to the master and the slave and two struct list_head members allowing it to hook into two lists (the master's list of "master" links and the slave's list of "slave" links). This allows the code to get to the link from each side (either from the master or from the slave) and follow it in each direction. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25PM / Domains: Add "wait for parent" status for generic PM domainsRafael J. Wysocki
The next patch will make it possible for a generic PM domain to have multiple parents (i.e. multiple PM domains it depends on). To prepare for that change it is necessary to change pm_genpd_poweron() so that it doesn't jump to the start label after running itself recursively for the parent domain. For this purpose, introduce a new PM domain status value GPD_STATE_WAIT_PARENT that will be set by pm_genpd_poweron() before calling itself recursively for the parent domain and modify the code in drivers/base/power/domain.c so that the GPD_STATE_WAIT_PARENT status is guaranteed to be preserved during the execution of pm_genpd_poweron() for the parent. This change also causes pm_genpd_add_subdomain() and pm_genpd_remove_subdomain() to wait for started pm_genpd_poweron() to complete and allows pm_genpd_runtime_resume() to avoid dropping the lock after powering on the PM domain. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-25PM / Domains: Implement subdomain counters as atomic fieldsRafael J. Wysocki
Currently, pm_genpd_poweron() and pm_genpd_poweroff() need to take the parent PM domain's lock in order to modify the parent's counter of active subdomains in a nonracy way. This causes the locking to be considerably complex and in fact is not necessary, because the subdomain counters may be implemented as atomic fields and they won't have to be modified under a lock. Replace the unsigned in sd_count field in struct generic_pm_domain by an atomic_t one and modify the code in drivers/base/power/domain.c to take this change into account. This patch doesn't change the locking yet, that is going to be done in a separate subsequent patch. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-08-14PM / Domains: Fix build for CONFIG_PM_RUNTIME unsetRafael J. Wysocki
Function genpd_queue_power_off_work() is not defined for CONFIG_PM_RUNTIME, so pm_genpd_poweroff_unused() causes a build error to happen in that case. Fix the problem by making pm_genpd_poweroff_unused() depend on CONFIG_PM_RUNTIME too. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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>
2011-07-11PM / 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>
2011-07-11PM / 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>