There are problems with calling pm_runtime_force_suspend/resume()
to "stop" and "start" devices in genpd_finish_suspend() and
genpd_resume_noirq() (and in analogous hibernation-specific genpd
callbacks) after commit 122a2237 (PM / Domains: Stop/start
devices during system PM suspend/resume in genpd) as those routines
do much more than just "stopping" and "starting" devices (which was
the stated purpose of that commit) unnecessarily and may not play
well with system-wide PM driver callbacks.

First, consider the pm_runtime_force_suspend() in
genpd_finish_suspend().  If the current runtime PM status of the
device is "suspended", that function most likely does the right thing
by ignoring the device, because it should have been "stopped" already
and whatever needed to be done to deactivate it shoud have been done.
In turn, if the runtime PM status of the device is "active",
genpd_runtime_suspend() is called for it (indirectly) and (1) runs
the ->runtime_suspend callback provided by the device's driver
(assuming no bus type with ->runtime_suspend of its own), (2) "stops"
the device and (3) checks if the domain can be powered down, and then
(4) the device's runtime PM status is changed to "suspended".  Out of
the four actions above (1) is not necessary and it may be outright
harmful, (3) is pointless and (4) is questionable.  The only
operation that needs to be carried out here is (2).

The reason why (1) is not necessary is because the system-wide
PM callbacks provided by the device driver for the transition in
question have been run and they should have taken care of the
driver's part of device suspend already.  Moreover, it may be
harmful, because the ->runtime_suspend callback may want to
access the device which is partially suspended at that point
and may not be responsive.  Also, system-wide PM callbacks may
have been run already (in the previous phases of the system
transition under way) for the device's parent or for its supplier
devices (if any) and the device may not be accessible because of
that.

There also is no reason to do (3), because genpd_finish_suspend()
will repeat it anyway, and (4) potentially causes confusion to ensue
during the subsequent system transition to the working state.

Consider pm_runtime_force_resume() in genpd_resume_noirq() now.
It runs genpd_runtime_resume() for all devices with runtime PM
status set to "suspended", which includes all of the devices
whose runtime PM status was changed by pm_runtime_force_suspend()
before and may include some devices already suspended when the
pm_runtime_force_suspend() was running, which may be confusing.  The
genpd_runtime_resume() first tries to power up the domain, which
(again) is pointless, because genpd_resume_noirq() has done that
already.  Then, it "starts" the device and runs the ->runtime_resume
callback (from the driver, say) for it.  If all is well, the device
is left with the runtime PM status set to "active".

Unfortunately, running the driver's ->runtime_resume callback
before its system-wide PM callbacks and possibly before some
system-wide PM callbacks of the parent device's driver (let
alone supplier drivers) is asking for trouble, especially if
the device had been suspended before pm_runtime_force_suspend()
ran previously or if the callbacks in question expect to be run
back-to-back with their suspend-side counterparts.  It also should
not be necessary, because the system-wide PM driver callbacks that
will be invoked for the device subsequently should take care of
resuming it just fine.

[Running the driver's ->runtime_resume callback in the "noirq"
phase of the transition to the working state may be problematic
even for devices whose drivers do use pm_runtime_force_resume()
in (or as) their system-wide PM callbacks if they have suppliers
other than their parents, because it may cause the supplier to
be resumed after the consumer in some cases.]

Because of the above, modify genpd as follows:

 1. Change genpd_finish_suspend() to only "stop" devices with
    runtime PM status set to "active" (without invoking runtime PM
    callbacks for them, changing their runtime PM status and so on).

    That doesn't change the handling of devices whose drivers use
    pm_runtime_force_suspend/resume() in (or as) their system-wide
    PM callbacks and addresses the issues described above for the
    other devices.

 2. Change genpd_resume_noirq() to only "start" devices with
    runtime PM status set to "active" (without invoking runtime PM
    callbacks for them, changing their runtime PM status and so on).

    Again, that doesn't change the handling of devices whose drivers
    use pm_runtime_force_suspend/resume() in (or as) their system-wide
    PM callbacks and addresses the described issues for the other
    devices.  Devices with runtime PM status set to "suspended"
    are not started with the assumption that they will be resumed
    later, either by pm_runtime_force_resume() or via runtime PM.

 3. Change genpd_restore_noirq() to follow genpd_resume_noirq().

    That causes devices already suspended before hibernation to be
    left alone (which also is the case without the change) and
    avoids running the ->runtime_resume driver callback too early
    for the other devices.

 4. Change genpd_freeze_noirq() and genpd_thaw_noirq() in accordance
    with the above modifications.

Fixes: 122a2237 (PM / Domains: Stop/start devices during system PM suspend/resume in genpd)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>

Commit 10da6542 (PM / Domains: Call driver's noirq callbacks)
started to respect driver's noirq callbacks, but while doing that it
also introduced a few potential problems.

More precisely, in genpd_finish_suspend() and genpd_resume_noirq()
the noirq callbacks at the driver level should be invoked, no matter
of whether dev->power.wakeup_path is set or not.

Additionally, the commit in question also made genpd_resume_noirq()
to ignore the return value from pm_runtime_force_resume().

Let's fix both these issues!

Fixes: 10da6542 (PM / Domains: Call driver's noirq callbacks)
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently the generic PM Domain code code checks for the presence of
both (generic) "power-domains" and (Samsung Exynos legacy)
"samsung,power-domain" properties in all device tree nodes representing
devices.

There are two issues with this:
  1. This imposes a small boot-time penalty on all platforms using DT,
  2. Platform-specific checks do not really belong in core framework
     code.

Remove the platform-specific check, as the last user of
"samsung,power-domain" was removed in commit 46dcf0ff ("ARM:
dts: exynos: Remove exynos4415.dtsi").  All other users were converted
before in commit 0da65870 ("ARM: dts: convert to generic power
domain bindings for exynos DT").
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

During system-wide PM, genpd relies on its PM callbacks to be invoked for
all its attached devices, as to deal with powering off/on the PM domain. In
other words, genpd is not compatible with the direct_complete path, if
executed by the PM core for any of its attached devices.

However, when genpd's ->prepare() callback invokes pm_generic_prepare(), it
does not take into account that it may return 1. Instead it treats that as
an error internally and expects the PM core to abort the prepare phase and
roll back. This leads to genpd not properly powering on/off the PM domain,
because its internal counters gets wrongly balanced.

To fix the behaviour, allow drivers to return 1 from their ->prepare()
callbacks, but let's return 0 from genpd's ->prepare() callback in such
case, as that prevents the PM core from running the direct_complete path
for the device.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The special value of 0 for device resume latency PM QoS means
"no restriction", but there are two problems with that.

First, device resume latency PM QoS requests with 0 as the
value are always put in front of requests with positive
values in the priority lists used internally by the PM QoS
framework, causing 0 to be chosen as an effective constraint
value.  However, that 0 is then interpreted as "no restriction"
effectively overriding the other requests with specific
restrictions which is incorrect.

Second, the users of device resume latency PM QoS have no
way to specify that *any* resume latency at all should be
avoided, which is an artificial limitation in general.

To address these issues, modify device resume latency PM QoS to
use S32_MAX as the "no constraint" value and 0 as the "no
latency at all" one and rework its users (the cpuidle menu
governor, the genpd QoS governor and the runtime PM framework)
to follow these changes.

Also add a special "n/a" value to the corresponding user space I/F
to allow user space to indicate that it cannot accept any resume
latencies at all for the given device.

Fixes: 85dc0b8a (PM / QoS: Make it possible to expose PM QoS latency constraints)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323Reported-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NReinette Chatre <reinette.chatre@intel.com>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: NTero Kristo <t-kristo@ti.com>
Reviewed-by: NRamesh Thomas <ramesh.thomas@intel.com>

The genpd governor currently uses negative PM QoS values to indicate
the "no suspend" condition and 0 as "no restriction", but it doesn't
use them consistently.  Moreover, it tries to refresh QoS values for
already suspended devices in a quite questionable way.

For the above reasons, rework it to be a bit more consistent.

First off, note that dev_pm_qos_read_value() in
dev_update_qos_constraint() and __default_power_down_ok() is
evaluated for devices in suspend.  Moreover, that only happens if the
effective_constraint_ns value for them is negative (meaning "no
suspend").  It is not evaluated in any other cases, so effectively
the QoS values are only updated for devices in suspend that should
not have been suspended in the first place.  In all of the other
cases, the QoS values taken into account are the effective ones from
the time before the device has been suspended, so generally devices
need to be resumed and suspended again for new QoS values to take
effect anyway.  Thus evaluating dev_update_qos_constraint() in
those two places doesn't make sense at all, so drop it.

Second, initialize effective_constraint_ns to 0 ("no constraint")
rather than to (-1) ("no suspend"), which makes more sense in
general and in case effective_constraint_ns is never updated
(the device is in suspend all the time or it is never suspended)
it doesn't affect the device's parent and so on.

Finally, rework default_suspend_ok() to explicitly handle the
"no restriction" and "no suspend" special cases.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: NTero Kristo <t-kristo@ti.com>
Reviewed-by: NRamesh Thomas <ramesh.thomas@intel.com>

There are no more users left of the gpd_dev_ops.active_wakeup()
callback.  All have been converted to GENPD_FLAG_ACTIVE_WAKEUP.
Hence remove the callback.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
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>

It is quite common for PM Domains to require slave devices to be kept
active during system suspend if they are to be used as wakeup sources.
To enable this, currently each PM Domain or driver has to provide its
own gpd_dev_ops.active_wakeup() callback.

Introduce a new flag GENPD_FLAG_ACTIVE_WAKEUP to consolidate this.
If specified, all slave devices configured as wakeup sources will be
kept active during system suspend.

PM Domains that need more fine-grained controls, based on the slave
device, can still provide their own callbacks, as before.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
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>

The PM QoS flag PM_QOS_FLAG_REMOTE_WAKEUP is not used consistently
and the vast majority of code simply assumes that remote wakeup
should be enabled for devices in runtime suspend if they can
generate wakeup signals, so drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Some platforms have the capability to configure the performance state of
PM domains. This patch enhances the genpd core to support such
platforms.

The performance levels (within the genpd core) are identified by
positive integer values, a lower value represents lower performance
state.

This patch adds a new genpd API, which is called by user drivers (like
OPP framework):

- int dev_pm_genpd_set_performance_state(struct device *dev,
					 unsigned int state);

  This updates the performance state constraint of the device on its PM
  domain. On success, the genpd will have its performance state set to a
  value which is >= "state" passed to this routine. The genpd core calls
  the genpd->set_performance_state() callback, if implemented,
  else -ENODEV is returned to the caller.

The PM domain drivers need to implement the following callback if they
want to support performance states.

- int (*set_performance_state)(struct generic_pm_domain *genpd,
			       unsigned int state);

  This is called internally by the genpd core on several occasions. The
  genpd core passes the genpd pointer and the aggregate of the
  performance states of the devices supported by that genpd to this
  callback. This callback must update the performance state of the genpd
  (in a platform dependent way).

The power domains can avoid supplying above callback, if they don't
support setting performance-states.

Currently we aren't propagating performance state changes of a subdomain
to its masters as we don't have hardware that needs it right now. Over
that, the performance states of subdomain and its masters may not have
one-to-one mapping and would require additional information. We can get
back to this once we have hardware that needs it.
Tested-by: NRajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Most of the functions names has already moved the genpd naming rules,
however let's make this complete to avoid any further confusions.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Now that we have a custom printf format specifier, convert users of
full_name to use %pOF instead. This is preparation to remove storing
of the full path string for each node.
Signed-off-by: NRob Herring <robh@kernel.org>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch extends the existing generic power domain debugfs.
Changes involve the following
- Introduce a unique debugfs entry for each generic power domain with the
  following attributes
	- current_state - Displays current state of the domain.
	- devices - Displays the devices associated with this domain.
	- sub_domains - Displays the sub power domains.
	- active_time - Displays the time the domain was in active state
			in ms.
	- total_idle_time - Displays the time the domain was in any of the idle
			states in ms.
	- idle_states - Displays the various idle states and the time
			spent in each idle state in ms.
Signed-off-by: NThara Gopinath <thara.gopinath@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch adds support to calculate the time spent by the generic
power domains in on and various idle states.
Signed-off-by: NThara Gopinath <thara.gopinath@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
the PM domain for the device unconditionally.

When subsequent attempts are made to call genpd_dev_pm_attach, it may
return -EEXISTS checking dev->pm_domain without re-attempting to call
attach_dev or power_on.

platform_drv_probe then attempts to call drv->probe as the return value
-EEXIST != -EPROBE_DEFER, which may end up in a situation where the
device is accessed without it's power domain switched on.

Fixes: f104e1e5 (PM / Domains: Re-order initialization of generic_pm_domain_data)
Cc: 4.4+ <stable@vger.kernel.org> # v4.4+
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When CONFIG_PM_SLEEP is disabled, we don't have a pm_genpd_poweroff_noirq
function definition:

drivers/base/power/domain.c: In function 'pm_genpd_init':
drivers/base/power/domain.c:1549:37: error: 'pm_genpd_poweroff_noirq' undeclared (first use in this function); did you mean 'genpd_power_off_unused'?

This adds another NULL definition for it, just like we already have
for the other _noirq handlers.

Fixes: 10da6542 (PM / Domains: Call driver's noirq callbacks)
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert commit 8b55e55e (PM / Domains: Handle safely
genpd_syscore_switch() call on non-genpd device) which was misguided
(the change made by it was not necessary) and it introduced a call to
a function that may sleep into an atomic context code path.
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

of_genpd_remove_last() iterates over list of domains and removes
matching element thus it has to use safe version of list iteration.

Fixes: 17926551 (PM / Domains: Add support for removing nested PM domains by provider)
Cc: 4.9+ <stable@vger.kernel.org> # 4.9+
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

of_genpd_del_provider() iterates over list of domain provides and
removes matching element thus it has to use safe version of list
iteration.

Fixes: aa42240a (PM / Domains: Add generic OF-based PM domain look-up)
Cc: 3.19+ <stable@vger.kernel.org> # 3.19+
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

pm_genpd_remove_subdomain() iterates over domain's master_links list and
removes matching element thus it has to use safe version of list
iteration.

Fixes: f721889f ("PM / Domains: Support for generic I/O PM domains (v8)")
Cc: 3.1+ <stable@vger.kernel.org> # 3.1+
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

genpd_syscore_switch() had two problems:
 1. It silently assumed that device, it is being called for, belongs
    to generic power domain and used container_of() on its power
    domain pointer.  Such assumption might not be true always.

2. It iterated over list of generic power domains without holding
   gpd_list_lock mutex thus list could have been modified at the same
   time.

Usage of genpd_lookup_dev() solves both problems as it is safe a call
for non-generic power domains and uses mutex when iterating.
Reported-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently genpd installs its own noirq callbacks, but never calls down
to the driver's corresponding callbacks. Add these calls.
Signed-off-by: NMikko Perttunen <mperttunen@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Mark pointer to struct generic_pm_domain const (either passed in
argument or used localy in a function), whenever it is not modifed by
the function itself.
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The pm_domain_data (pdd) pointer is set from genpd_alloc_dev_data() and
pdd->dev is guaranteed to be valid. There is no need to check pdd and
pdd->dev in rest of the code as pdd->dev will always be valid for a non
NULL pdd pointer.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Allow generic power domain providers to override the ->xlate() callback
in case the default genpd_xlate_onecell() translation callback is not
good enough.

One potential use-case for this is to allow generic power domains to be
specified by an ID rather than an index.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NThierry Reding <treding@nvidia.com>

There is no reason that a platform genpd driver registered using
of_genpd_add_provider_simple needs to be constrained to having no cells
in the "power-domains" phandle. Currently the genpd framework will fail
if any arguments are passed with for a simple provider but the framework
does not actually care, so remove the check for phandle argument count.

This will allow greater flexibility for genpd providers to use their own
arguments that are passed in the phandle and interpret them however they
see fit.
Acked-by: NKevin Hilman <khilman@baylibre.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NDave Gerlach <d-gerlach@ti.com>
Signed-off-by: NSantosh Shilimkar <ssantosh@kernel.org>

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>