domain-idle-states property may have phandles to idle state bindings
that may not be compatible with idle state definition defined in [1].
Such phandles would just be ignored and not throw and error when read by
the domain core.
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When an IRQ safe device is attached to a no sleep domain, genpd prints a
warning once, as to indicate it is a suboptimal configuration from power
consumption point of view.

However the warning doesn't make sense for an always on domain, since it
anyway remains powered on. Therefore, let's change to not print the warning
for this configuration.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The current code in genpd_sync_power_off(), doesn't care about potential
errors being returned from genpd's ->power_off() callback.

Obviously this behaviour could lead to problems, such as incorrectly
setting the genpd's status to GPD_STATE_POWER_OFF, but also to incorrectly
decrease the subdomain count for the masters, which potentially allows them
to be powered off in the next recursive call to genpd_sync_power_off().

Let's fix this behaviour by bailing out when the ->power_off() callback
returns an error code.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The current way to implement an always on PM domain consists of returning
-EBUSY from the ->power_off() callback. This is a bit different compared to
using the always on genpd governor, which prevents the PM domain from being
powered off via runtime suspend, but not via system suspend.

The approach to return -EBUSY from the ->power_off() callback to support
always on PM domains in genpd is suboptimal. That is because it requires
genpd to follow the regular execution path of the power off sequence, which
ends by invoking the ->power_off() callback.

To enable genpd to early abort the power off sequence for always on PM
domains, it needs static information about these configurations. Therefore
let's add a new genpd configuration flag, GENPD_FLAG_ALWAYS_ON.

Users of the new GENPD_FLAG_ALWAYS_ON flag, are by genpd required to make
sure the PM domain is powered on before calling pm_genpd_init(). Moreover,
users don't need to implement the ->power_off() callback, as genpd doesn't
ever invoke it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There exists several similar validations of the genpd->status, against
GPD_STATE_ACTIVE and GPD_STATE_POWER_OFF. Let's clean up this code by
converting to use a helper macro, genpd_status_on().
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There is no point running the conditional 'if' statement if the genpd
isn't present.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Once a subdomain is powered off, genpd queues a power off work for each of
the subdomain's corresponding masters, thus postponing the masters to be
powered off to a later point.

When genpd used intermediate power off states, which was removed in
commit ba2bbfbf ("PM / Domains: Remove intermediate states from the
power off sequence"), this behaviour made sense, but now it simply doesn't.

Genpd can easily try to power off the masters in the same context as the
subdomain, of course by acquiring/releasing the lock. Then, let's convert
to this behaviour, as it avoids unnecessary works from being queued.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The parameter name is_async, for genpd_power_off() gives a poor description
of its purpose. To clarify, let's rename it to one_dev_on and update the
documentation of it in the function header.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Following changes in genpd_power_on() makes it invoke genpd_power_off().
To enable these changes and avoiding to declare genpd_power_off(), let's
move its implementation above genpd_power_on(). In this way, following
changes should become easier to review.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

As the PM core may invoke the *noirq() callbacks asynchronously, the
current lock-less approach in genpd doesn't work. The consequence is that
we may find concurrent operations racing to power on/off the PM domain.

As of now, no immediate errors has been reported, but it's probably only a
matter time. Therefor let's fix the problem now before this becomes a real
issue, by deploying the locking scheme to the relevant functions.
Reported-by: NBrian Norris <briannorris@chromium.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The earlier comment stated that the dev_warn_once() was going to be printed
once per device. Let's fix that, as dev_warn_once() is printed only once,
no matter of the device.
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NLina Iyer <lina.iyer@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently the mix of genpd_poweron(), genpd_power_on(),
genpd_sync_poweron() and the ->power_on() callback, makes
a bit difficult to follow the path of execution. The similar
applies to the functions dealing with power off.

In a way to improve this understanding, let's do the following renaming:

genpd_power_on() ->  _genpd_power_on()
genpd_poweron() -> genpd_power_on()
genpd_sync_poweron() -> genpd_sync_power_on()

genpd_power_off() -> _genpd_power_off()
genpd_poweroff() -> genpd_power_off()
genpd_sync_poweroff() -> genpd_sync_power_off()
genpd_poweroff_unused() -> genpd_power_off_unused()
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch fixes the following gcc warning:

drivers/base/power/domain.c: In function ‘genpd_runtime_resume’:
drivers/base/power/domain.c:642:14: warning: ‘time_start’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
   elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start)

The same problem (in another function in this same file) was fixed in
commit d33d5a6c (avoid spurious "may be used uninitialized" warning)
Signed-off-by: NAugusto Mecking Caringi <augustocaringi@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The timer type simplifications caused a new gcc warning:

  drivers/base/power/domain.c: In function ‘genpd_runtime_suspend’:
  drivers/base/power/domain.c:562:14: warning: ‘time_start’ may be used uninitialized in this function [-Wmaybe-uninitialized]
     elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));

despite the actual use of "time_start" not having changed in any way.
It appears that simply changing the type of ktime_t from a union to a
plain scalar type made gcc check the use.

The variable wasn't actually used uninitialized, but gcc apparently
failed to notice that the conditional around the use was exactly the
same as the conditional around the initialization of that variable.

Add an unnecessary initialization just to shut up the compiler.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Re-using idle state definition provided by arm,idle-state for domain
idle states creates a lot of confusion and limits further evolution of
the domain idle definition. To keep things clear and simple, define a
idle states for domain using a new compatible "domain-idle-state".

Fix existing PM domains code to look for the newly defined compatible.
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

EPROBE_DEFER is not an error, hence printing an error message like

    renesas_irqc e61c0000.interrupt-controller: failed to add to PM domain always-on: -517

may confuse the user.

Suppress the error message in case of EPROBE_DEFER to fix this.
Reported-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The first argument of WARN() is the condition, followed by the message.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The return from of_count_phandle_with_args can be negative, so we
should avoid kcalloc of a negative count of genpd_power_stat structs
by sanity checking if count is zero or less.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NKevin Hilman <khilman@baylibre.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Generic Power Domains currently support turning on/off only in process
context. This prevents the usage of PM domains for domains that could be
powered on/off in a context where IRQs are disabled. Many such domains
exist today and do not get powered off, when the IRQ safe devices in
that domain are powered off, because of this limitation.

However, not all domains can operate in IRQ safe contexts. Genpd
therefore, has to support both cases where the domain may or may not
operate in IRQ safe contexts. Configuring genpd to use an appropriate
lock for that domain, would allow domains that have IRQ safe devices to
runtime suspend and resume, in atomic context.

To achieve domain specific locking, set the domain's ->flag to
GENPD_FLAG_IRQ_SAFE while defining the domain. This indicates that genpd
should use a spinlock instead of a mutex for locking the domain. Locking
is abstracted through genpd_lock() and genpd_unlock() functions that use
the flag to determine the appropriate lock to be used for that domain.

Domains that have lower latency to suspend and resume and can operate
with IRQs disabled may now be able to save power, when the component
devices and sub-domains are idle at runtime.

The restriction this imposes on the domain hierarchy is that non-IRQ
safe domains may not have IRQ-safe subdomains, but IRQ safe domains may
have IRQ safe and non-IRQ safe subdomains and devices.
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Abstract genpd lock/unlock calls, in preparation for domain specific
locks added in the following patches.
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Save the fwnode for the genpd state in the state node. PM Domain clients
may use the fwnode to read in the platform specific domain state
properties and associate them with the state.
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch allows domains to define idle states in the DT. SoC's can
define domain idle states in DT using the "domain-idle-states" property
of the domain provider. Add API to read the idle states from DT that can
be set in the genpd object.

This patch is based on the original patch by Marc Titinger.
Signed-off-by: NMarc Titinger <mtitinger+renesas@baylibre.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Allow PM Domain states to be defined dynamically by the drivers. This
removes the limitation on the maximum number of states possible for a
domain.
Suggested-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NLina Iyer <lina.iyer@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

These are internal static functions to genpd. Let's conform to the naming
rules, by dropping the "pm_" prefix from these.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Measure latency does by itself contribute to an increased latency, thus we
should avoid it when it isn't needed.

Currently genpd measures latencies in the system PM phase for the
->power_on|off() callbacks, except in the syscore case when it's not
allowed to use ktime_get() as timekeeping may be suspended.

Since there should be plenty of occasions during runtime PM to perform
these measurements, let's rely on that and drop them from system PM. This
will also make it consistent for how measurements are done of the runtime
PM callbacks (as those may be invoked during system PM).
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In cases when the PM domain haven't assigned a system PM callback, the PM
core fall-backs to check for the callback at the driver level instead.
This makes it redundant to assign a pm_generic_* helper function to a
corresponding system PM callback at a PM domain level.

Therefore, let's remove these assignments in pm_genpd_init().
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There's no need to validate the PM domain by using genpd_lookup_dev() when
removing the device via genpd's genpd_dev_pm_detach() function. That's
because this function can't be called, unless there is a valid PM domain
for the device.

To simplify the behaviour, let's move code from pm_genpd_remove_device()
into a new internal function, genpd_remove_device(), which is called from
pm_genpd_remove_device() and genpd_dev_pm_detach().
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLina Iyer <lina.iyer@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In platforms such as Rockchip's, the array of domains isn't always
filled without holes, as which domains are present depend on the
particular SoC revision.

By allowing holes to be in the array, such SoCs can still use a single
set of constants to index the array of power domains.

Fixes: 0159ec67 (PM / Domains: Verify the PM domain is present when adding a provider)
Signed-off-by: NTomeu Vizoso <tomeu.vizoso@collabora.com>
Acked-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NHeiko Stuebner <heiko@sntech.de>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Acked-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If a device supports PM domains that are subdomains of another PM
domain, then the PM domains should be removed in reverse order to
ensure that the subdomains are removed first. Furthermore, if there is
more than one provider, then there needs to be a way to remove the
domains in reverse order for a specific provider.

Add the function of_genpd_remove_last() to remove the last PM domain
added by a given PM domain provider and return the generic_pm_domain
structure for the PM domain that was removed.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The genpd framework allows users to add PM domains via the pm_genpd_init()
function, however, there is no corresponding function to remove a PM
domain. For most devices this may be fine as the PM domains are never
removed, however, for devices that wish to populate the PM domains from
within a driver, having the ability to remove a PM domain if the probing
of the device fails or the driver is unloaded is necessary.

Add the function pm_genpd_remove() to remove a PM domain by referencing
it's generic_pm_domain structure. Note that the bulk of the code that
removes the PM domain is placed in a separate local function
genpd_remove() (which is called by pm_genpd_remove()). The code is
structured in this way to prepare for adding another function to remove
a PM domain by provider that will also call genpd_remove(). Note that
users of genpd_remove() must call this function with the mutex,
gpd_list_lock, held.

PM domains can only be removed if the associated provider has been
removed, they are not a parent domain to another PM domain and have no
devices associated with them.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

It is possible that a device has more than one provider of PM domains
and to support the removal of a PM domain by provider, it is necessary
to store a reference to the provider in the PM domain structure.
Therefore, store a reference to the firmware node handle in the PM
domain structure and populate it when providers (only device-tree based
providers are currently supported by PM domains) are registered.

Please note that when removing PM domains, it is necessary to verify
that the PM domain provider has been removed from the list of providers
before the PM domain can be removed. To do this add another member to
the PM domain structure that indicates if the provider is present and
set this member accordingly when providers are added and removed.

Initialise the 'provider' and 'has_provider' members of the
generic_pm_domain structure when a PM domains is added by calling
pm_genpd_init().
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In order to remove PM domains safely from the list of PM domains,
it is necessary to adding locking for the PM domain list around any
places where devices or subdomains are added to a PM domain.

There are places where a reference to a PM domain is obtained via
calling of_genpd_get_from_provider() before adding the device or the
subdomain. In these cases a lock for the PM domain list needs to be
held around the call to of_genpd_get_from_provider() and the call to
add the device/subdomain. To avoid deadlocks by multiple attempts to
obtain the PM domain list lock, add functions genpd_add_device() and
genpd_add_subdomain() which require the user to hold the PM domain
list lock when calling.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When a PM domain provider is added, there is currently no way to tell if
any PM domains associated with the provider are present. Naturally, the
PM domain provider should not be registered if the PM domains have not
been added. Nonetheless, verify that the PM domain(s) associated with a
provider are present when registering the PM domain provider.

This change adds a dependency on the function pm_genpd_present() when
CONFIG_PM_GENERIC_DOMAINS_OF is enabled and so ensure this function is
available when CONFIG_PM_GENERIC_DOMAINS_OF selected.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Functions __of_genpd_xlate_simple(), __of_genpd_xlate_onecell() and
__of_genpd_add_provider() are not used outside of the core generic PM
domain code. Therefore, reduce the number of APIs exposed by making
these static. At the same time don't expose the typedef for
genpd_xlate_t either and make this a local definition as well.

The functions are renamed to follow the naming conventions for static
functions in the generic PM domain core.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There should be no need to expose the generic_pm_domain structure to
clients and this eliminates the need to implement reference counting for
any external reference to a PM domain. Therefore, make the functions
pm_genpd_lookup_dev() and of_genpd_get_from_provider() private to the
PM domain core. The functions are renamed in accordance with the naming
conventions for genpd static functions.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Ideally, if we are returning a reference to a PM domain via a call to
of_genpd_get_from_provider(), then we should keep track of such
references via a reference count. The reference count could then be used
to determine if a PM domain can be safely removed. Alternatively, it is
possible to avoid such external references by providing APIs to access
the PM domain and hence, eliminate any calls to
of_genpd_get_from_provider().

Add new helper functions for adding a device and a subdomain to a PM
domain when using device-tree, so that external calls to
of_genpd_get_from_provider() can be removed.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Debugfs support for PM domains is only enabled if both CONFIG_PM_DEBUG
and CONFIG_PM_ADVANCED_DEBUG are enabled. CONFIG_PM_ADVANCED_DEBUG is
described as "extra PM attributes in sysfs for low-level
debugging/testing" which does not seem related.

Given that the debugfs for PM domains only allows users to view the
state of the PM domains, always enable debugfs support for PM domains
if PM domains and debugfs support is enabled.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The are already cases when pm_genpd_init() can fail. Currently we hide the
failures instead of propagating an error code, which is a better method.

Moreover, to prepare for future changes like moving away from using a
fixed array-size of the struct genpd_power_state, to instead dynamically
allocate data for it, the pm_genpd_init() API needs to be able to return
an error code, as allocation can fail.

Current users of the pm_genpd_init() is thus requested to start dealing
with error codes. In the transition phase, users will have to live with
only error messages being printed to log.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Not all subsystems/drivers that manages devices attached to a genpd
makes use of the pm_runtime_force_suspend|resume() helper functions
to deal with system PM suspend/resume.

In cases like these and when genpd's ->stop|start() callbacks are
used for the device, invoke the pm_runtime_force_suspend|resume()
helper functions from genpd's "noirq" system PM callbacks. In this
way we make sure to "stop" the device on suspend and to "start" it
on resume.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In cases when a PM domain isn't powered off when genpd's ->prepare()
callback is invoked, genpd runtime resumes and disables runtime PM for the
device. This behaviour was needed when genpd managed intermediate states
during the power off sequence, as to maintain proper low power states of
devices during system PM suspend/resume.

Commit ba2bbfbf (PM / Domains: Remove intermediate states from the
power off sequence), enables genpd to improve its behaviour in that
respect.

The PM core disables runtime PM at __device_suspend_late() before it calls
a system PM "late" callback for a device. When resuming a device, after a
corresponding "early" callback has been invoked, the PM core re-enables
runtime PM.

By changing genpd to allow runtime PM according to the same system PM
phases as the PM core, devices can be runtime resumed by their
corresponding subsystem/driver when really needed.

In this way, genpd no longer need to runtime resume the device from its
->prepare() callback. In most cases that avoids unnecessary and energy-
wasting operations of runtime resuming devices that have nothing to do,
only to runtime suspend them shortly after.

Although, because of changing this behaviour in genpd and due to that
genpd powers on the PM domain unconditionally in the system PM resume
"noirq" phase, it could potentially cause a PM domain to stay powered
on even if it's unused after the system has resumed. To avoid this,
schedule a power off work when genpd's system PM ->complete() callback
has been invoked for the last device in the PM domain.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@baylibre.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>