Commit ba2bbfbf ("PM / Domains: Remove intermediate states..") changed
the power off sequence (pm_genpd_poweroff()), which from locking point of
view means the genpd mutex is held throughout the sequence.

The above change means the in_progress counter can't be updated while
pm_genpd_poweroff() is executing, which allows us to remove the counter.

Instead we inform pm_genpd_poweroff() via a bool parameter, to indicate
whether we call it from the scheduled work or from the ->runtime_suspend()
callback, since that all that matters.
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>

The power domains code allows to tie a cpuidle state with a power domain.

Preventing the cpuidle framework to enter a specific idle state by disabling
from the power domain framework is a good idea. Unfortunately, the current
implementation has some gaps with a SMP system and a complex cpuidle
implementation. Enabling a power domain wakes up all the cpus even if a cpu
does not belong to the power domain.

There is some work to do a logical representation with the power domains of
the hardware dependencies (eg. a cpu belongs to a power domains, these power
domains belong to a higher power domain for a cluster, etc ...). A new code
relying on the genpd hierarchy to disable the idle states would make more
sense.

As the unique user of this code has been removed, let's wipe out this code
to prevent new user and to have a clean place to put a new implementation.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

As all users of the named based APIs now have converted to the non-named
based APIs, the time has come to remove them.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The governor dummies for the !CONFIG_PM_GENERIC_DOMAINS case are
unusable, as a governors is always referred to by taking its address,
which you can't do with a literal NULL pointer.

I.e.

	pm_genpd_init(genpd, &simple_qos_governor, false);

fails to compile with:

	error: lvalue required as unary '&' operand

Hence just remove the governor dummies.
Signed-off-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>

Genpd's ->runtime_suspend() (assigned to pm_genpd_runtime_suspend())
doesn't immediately walk the hierarchy of ->runtime_suspend() callbacks.
Instead, pm_genpd_runtime_suspend() calls pm_genpd_poweroff() which
postpones that until *all* the devices in the genpd are runtime suspended.

When pm_genpd_poweroff() discovers that the last device in the genpd is
about to be runtime suspended, it calls __pm_genpd_save_device() for *all*
the devices in the genpd sequentially. Furthermore,
__pm_genpd_save_device() invokes the ->start() callback, walks the
hierarchy of the ->runtime_suspend() callbacks and invokes the ->stop()
callback. This causes a "thundering herd" problem.

Let's address this issue by having pm_genpd_runtime_suspend() immediately
walk the hierarchy of the ->runtime_suspend() callbacks, instead of
postponing that to the power off sequence via pm_genpd_poweroff(). If the
selected ->runtime_suspend() callback doesn't return an error code, call
pm_genpd_poweroff() to see if it's feasible to also power off the PM
domain.

Adopting this change enables us to simplify parts of the code in genpd,
for example the locking mechanism. Additionally, it gives some positive
side effects, as described below.

i)
One device's ->runtime_resume() latency is no longer affected by other
devices' latencies in a genpd.

The complexity genpd has to support the option to abort the power off
sequence suffers from latency issues. More precisely, a device that is
requested to be runtime resumed, may end up waiting for
__pm_genpd_save_device() to complete its operations for *another* device.
That's because pm_genpd_poweroff() can't confirm an abort request while it
waits for __pm_genpd_save_device() to return.

As this patch removes the intermediate states in pm_genpd_poweroff() while
powering off the PM domain, we no longer need the ability to abort that
sequence.

ii)
Make pm_runtime[_status]_suspended() reliable when used with genpd.

Until the last device in a genpd becomes idle, pm_genpd_runtime_suspend()
will return 0 without actually walking the hierarchy of the
->runtime_suspend() callbacks. However, by returning 0 the runtime PM core
considers the device as runtime_suspended, so
pm_runtime[_status]_suspended() will return true, even though the device
isn't (yet) runtime suspended.

After this patch, since pm_genpd_runtime_suspend() immediately walks the
hierarchy of the ->runtime_suspend() callbacks,
pm_runtime[_status]_suspended() will accurately reflect the status of the
device.

iii)
Enable fine-grained PM through runtime PM callbacks in drivers/subsystems.

There are currently cases were drivers/subsystems implements runtime PM
callbacks to deploy fine-grained PM (e.g. gate clocks, move pinctrl to
power-save state, etc.). While using the genpd, pm_genpd_runtime_suspend()
postpones invoking these callbacks until *all* the devices in the genpd
are runtime suspended. In essence, one runtime resumed device prevents
fine-grained PM for other devices within the same genpd.

After this patch, since pm_genpd_runtime_suspend() immediately walks the
hierarchy of the ->runtime_suspend() callbacks, fine-grained PM is enabled
throughout all the levels of runtime PM callbacks.

iiii)
Enable fine-grained PM for IRQ safe devices

Per the definition for an IRQ safe device, its runtime PM callbacks must
be able to execute in atomic context. In the path while genpd walks the
hierarchy of the ->runtime_suspend() callbacks for the device, it uses a
mutex. Therefore, genpd prevents that path to be executed for IRQ safe
devices.

As this patch changes pm_genpd_runtime_suspend() to immediately walk the
hierarchy of the ->runtime_suspend() callbacks and without needing to use
a mutex, fine-grained PM is enabled throughout all the levels of runtime
PM callbacks for IRQ safe devices.

Unfortunately this patch also comes with a drawback, as described in the
summary below.

Driver's/subsystem's runtime PM callbacks may be invoked even when the
genpd hasn't actually powered off the PM domain, potentially introducing
unnecessary latency.

However, in most cases, saving/restoring register contexts for devices are
typically fast operations or can be optimized in device specific ways
(e.g. shadow copies of register contents in memory, device-specific checks
to see if context has been lost before restoring context, etc.).

Still, in some cases the driver/subsystem may suffer from latency if
runtime PM is used in a very fine-grained manner (e.g. for each IO request
or xfer). To prevent that extra overhead, the driver/subsystem may deploy
the runtime PM autosuspend feature.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: NLina Iyer <lina.iyer@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The PM domain code contains two methods to get the generic PM domain
for a struct device.  One is dev_to_genpd() which is only safe when
we know for certain that the device has a generic PM domain attached.
The other is coded into genpd_dev_pm_detach() which ensures that the
PM domain in the struct device is a generic PM domain (and so is safer).

This commit factors out the safer version, documents it, and hides the
unsafe dev_to_genpd().
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

While adding devices to their PM domains, dev_pm_qos_add_notifier() was
invoked while allocating the generic_pm_domain_data for the device.

Since the generic_pm_domain_data's device pointer will be assigned
after allocation, the ->genpd_dev_pm_qos_notifier() callback could be
called prior having a valid pointer to the device. Similar scenario
existed while removing a device from a genpd.

To cope with these scenarios a mutex was used to protect the pointer to
the device.

By re-order the sequence for when dev_pm_qos_add|remove_notifier() are
invoked, we make sure the ->genpd_dev_pm_qos_notifier() callback are
always called with a valid device pointer available.

In this way, we eliminate the need for protecting the pointer and thus
we can remove the mutex from the struct generic_pm_domain_data.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The reference counting was needed when genpd supported PM domain device
callbacks. Since this option has been removed, let's also remove the
reference counting of the struct generic_pm_domain_data.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are currently no users of this API, let's remove it.

Additionally, if such feature would be needed future wise, a better
option is likely use pm_runtime_set_active|suspended() in some form.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This function looks up a PM domain form the provider. This will be
useful to add parent/child domain relationship from the SoC specific
code. The caller of the function must make sure that PM domain provider
is already registered.
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NAmit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

After commit b2b49ccb (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is
selected) PM_RUNTIME is always set if PM is set, so quite a few
depend on CONFIG_PM or even may be dropped entirely in some cases.

Replace CONFIG_PM_RUNTIME with CONFIG_PM in the PM core code.
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

It's quite common for PM domains to use PM clocks. Typically from SOC
specific code, the per device PM clock list is created and
pm_clk_suspend|resume() are invoked to handle clock gating/ungating.

A step towards consolidation is to integrate PM clock support into
genpd, which is what this patch does.

In this initial step, the calls to the pm_clk_suspend|resume() are
handled within genpd, but the per device PM clock list still needs to
be created from SOC specific code. It seems reasonable to have gendp to
handle that as well, but that left to future patches to address.

It's not every users of genpd that are keen on using PM clocks, thus we
need to provide this a configuration option for genpd. Therefore let's
add flag field in the genpd struct to keep this information and define
a new GENDP_FLAG_PM_CLK bit for it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The definition of the struct pm_domain_data better belongs in the
header for the PM domains, let's move it there.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The initial state of the device's need_restore flag should'nt depend on
the current state of the PM domain. For example it should be perfectly
valid to attach an inactive device to a powered PM domain.

The pm_genpd_dev_need_restore() API allow us to update the need_restore
flag to somewhat cope with such scenarios. Typically that should have
been done from drivers/buses ->probe() since it's those that put the
requirements on the value of the need_restore flag.

Until recently, the Exynos SOCs were the only user of the
pm_genpd_dev_need_restore() API, though invoking it from a centralized
location while adding devices to their PM domains.

Due to that Exynos now have swithed to the generic OF-based PM domain
look-up, it's no longer possible to invoke the API from a centralized
location. The reason is because devices are now added to their PM
domains during the probe sequence.

Commit "ARM: exynos: Move to generic PM domain DT bindings"
did the switch for Exynos to the generic OF-based PM domain look-up,
but it also removed the call to pm_genpd_dev_need_restore(). This
caused a regression for some of the Exynos drivers.

To handle things more properly in the generic PM domain, let's change
the default initial value of the need_restore flag to reflect that the
state is unknown. As soon as some of the runtime PM callbacks gets
invoked, update the initial value accordingly.

Moreover, since the generic PM domain is verifying that all devices
are both runtime PM enabled and suspended, using pm_runtime_suspended()
while pm_genpd_poweroff() is invoked from the scheduled work, we can be
sure of that the PM domain won't be powering off while having active
devices.

Do note that, the generic PM domain can still only know about active
devices which has been activated through invoking its runtime PM resume
callback. In other words, buses/drivers using pm_runtime_set_active()
during ->probe() will still suffer from a race condition, potentially
probing a device without having its PM domain being powered. That issue
will have to be solved using a different approach.

This a log from the boot regression for Exynos5, which is being fixed in
this patch.

------------[ cut here ]------------
WARNING: CPU: 0 PID: 308 at ../drivers/clk/clk.c:851 clk_disable+0x24/0x30()
Modules linked in:
CPU: 0 PID: 308 Comm: kworker/0:1 Not tainted 3.18.0-rc3-00569-gbd9449f-dirty #10
Workqueue: pm pm_runtime_work
[<c0013c64>] (unwind_backtrace) from [<c0010dec>] (show_stack+0x10/0x14)
[<c0010dec>] (show_stack) from [<c03ee4cc>] (dump_stack+0x70/0xbc)
[<c03ee4cc>] (dump_stack) from [<c0020d34>] (warn_slowpath_common+0x64/0x88)
[<c0020d34>] (warn_slowpath_common) from [<c0020d74>] (warn_slowpath_null+0x1c/0x24)
[<c0020d74>] (warn_slowpath_null) from [<c03107b0>] (clk_disable+0x24/0x30)
[<c03107b0>] (clk_disable) from [<c02cc834>] (gsc_runtime_suspend+0x128/0x160)
[<c02cc834>] (gsc_runtime_suspend) from [<c0249024>] (pm_generic_runtime_suspend+0x2c/0x38)
[<c0249024>] (pm_generic_runtime_suspend) from [<c024f44c>] (pm_genpd_default_save_state+0x2c/0x8c)
[<c024f44c>] (pm_genpd_default_save_state) from [<c024ff2c>] (pm_genpd_poweroff+0x224/0x3ec)
[<c024ff2c>] (pm_genpd_poweroff) from [<c02501b4>] (pm_genpd_runtime_suspend+0x9c/0xcc)
[<c02501b4>] (pm_genpd_runtime_suspend) from [<c024a4f8>] (__rpm_callback+0x2c/0x60)
[<c024a4f8>] (__rpm_callback) from [<c024a54c>] (rpm_callback+0x20/0x74)
[<c024a54c>] (rpm_callback) from [<c024a930>] (rpm_suspend+0xd4/0x43c)
[<c024a930>] (rpm_suspend) from [<c024bbcc>] (pm_runtime_work+0x80/0x90)
[<c024bbcc>] (pm_runtime_work) from [<c0032a9c>] (process_one_work+0x12c/0x314)
[<c0032a9c>] (process_one_work) from [<c0032cf4>] (worker_thread+0x3c/0x4b0)
[<c0032cf4>] (worker_thread) from [<c003747c>] (kthread+0xcc/0xe8)
[<c003747c>] (kthread) from [<c000e738>] (ret_from_fork+0x14/0x3c)
---[ end trace 40cd58bcd6988f12 ]---

Fixes: a4a8c2c4 (ARM: exynos: Move to generic PM domain DT bindings)
Reported-and-tested0by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Convert the prototypes to return an int in order to support error
handling in these callbacks.

Also, as suggested by Dmitry Torokhov, pass the domain pointer for use
inside the callbacks, and so that they match the existing
power_on/power_off callbacks which currently take the domain pointer.
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
[ khilman: added domain as parameter to callbacks, as suggested by Dmitry ]
Signed-off-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The "cpu_data" are defined for some archs and thus conflicting with the
"cpu_data" member in the struct gpd_cpu_data. This causes a compiler
error for those archs.

Let's fix it by rename the member to cpuidle_data. In this context it
also seems appropriate to rename the struct to gpd_cpuidle_data to
better reflect its use.

Fixes: f48c767c (PM / Domains: Move dev_pm_domain_attach|detach() to pm_domain.h)
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The commit 46420dd7 (PM / Domains: Add APIs to attach/detach a PM
domain for a device) started using errno values in pm.h header file.
It also failed to include the header for these, thus it caused
compiler errors.

Instead of including the errno header to pm.h, let's move the functions
to pm_domain.h, since it's a better match.

Fixes: 46420dd7 (PM / Domains: Add APIs to attach/detach a PM domain for a device)
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are no active clients of the legacy API and we now also have a
better way to handle genpd DT support. So let's remove the legacy API.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

While a PM domain can enable PM runtime management of its devices' module
clocks by setting

	genpd->dev_ops.stop = pm_clk_suspend;
	genpd->dev_ops.start = pm_clk_resume;

this also requires registering the clocks with the pm_clk subsystem.
In the legacy case, this is handled by the platform code, after
attaching the device to its PM domain.

When the devices are instantiated from DT, devices are attached to their
PM domains by generic code, leaving no method for the platform-specific
PM domain code to register their clocks.

Add two callbacks, allowing a PM domain to perform platform-specific
tasks when a device is attached to or detached from a PM domain.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch introduces generic code to perform PM domain look-up using
device tree and automatically bind devices to their PM domains.

Generic device tree bindings are introduced to specify PM domains of
devices in their device tree nodes.

Backwards compatibility with legacy Samsung-specific PM domain bindings
is provided, but for now the new code is not compiled when
CONFIG_ARCH_EXYNOS is selected to avoid collision with legacy code.
This will change as soon as the Exynos PM domain code gets converted to
use the generic framework in further patch.

This patch was originally submitted by Tomasz Figa when he was employed
by Samsung.

Link: http://marc.info/?l=linux-pm&m=139955349702152&w=2Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Tested-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This is a pure code cleanup in the header file for the PM domain. No
functional change.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are currently no need to export default_stop_ok() as an API,
instead let's keep it local to the PM domain governor.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are no active users of this API. Let's remove it and if future
needs shows up we could consider to have a get/put API instead.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The pm_genpd_syscore_poweroff() API and pm_genpd_syscore_poweron() API
makes the pm_genpd_syscore_switch() API redundant.

Moreover, since there are no active users, let's just remove it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The genpd dev_irq_safe configuration somewhat overlaps with the runtime
PM pm_runtime_irq_safe() option. Also, currently genpd don't have a
good way to deal with these device. So, until we figured out if and how
to support this in genpd, let's remove the option to configure it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There no users of these callbacks, let's simplify the generic power
domain by removing them.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In a step of simplifying the generic power domain let's move away from
using these callbacks.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are no users of these APIs. To simplify the generic power domain
let's remove them.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make it possible to use domain names in operations connecting cpuidle
to and disconnecting it from a PM domain.  This is useful on
platforms where PM domain objects are organized in such a way that
the names of the domains are easier to use than the addresses of
those objects.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

The names of the cpuidle-related functions in
drivers/base/power/domain.c are inconsistent with the names of the
other exported functions in that file (the "pm_" prefix is missing
from them) and they are missing kerneldoc comments.

Fix that by adding the missing "pm_" prefix to the names of those
functions and add kerneldoc comments documenting them.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

It sometimes is necessary to turn on a given PM domain when only
the name of it is known and the domain pointer is not readily
available.  For this reason, add a new helper function,
pm_genpd_name_poweron(), allowing the caller to turn on a PM domain
using its name for identification.  To avoid code duplication,
move the domain lookup code to a separate function.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Add a new helper function, pm_genpd_add_subdomain_names(), allowing
the caller to add a subdomain to a generic PM domain using names for
domain identification (both domains have to be initialized before).

This function is useful for adding subdomains to PM domains whose
representations are stored in tables, when the caller doesn't know
the indices of the domain to add the subdomain to and of the
subdomain itself, but it knows the domains' names.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Add a new helper function __pm_genpd_name_add_device() allowing
a device to be added to a (registered) generic PM domain identified
by name.  Add a wrapper around it, pm_genpd_name_add_device(),
passing NULL as the last argument and reorganize pm_domains.h for the
new functions to be defined consistently with the existing ones.

These functions are useful for adding devices to PM domains whose
representations are stored in tables, when the caller doesn't know
the index of the domain to add the device to, but it knows the
domain's name.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

The syscore device PM flag is used to mark the devices (belonging to
a PM domain) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages.  That flag is
stored in the device's struct pm_subsys_data object whose address is
available from struct device.  However, in some situations it may be
convenient to set that flag before the device is added to a PM
domain, so it is better to move it directly to the "power" member of
struct device.  Then, it can be checked by the routines in
drivers/base/power/runtime.c and drivers/base/power/main.c, which is
more straightforward.

This also reduces the number of dev_gpd_data() invocations in the
generic PM domains framework, so the overhead related to the syscore
flag is slightly smaller.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NMagnus Damm <damm@opensource.se>

The always_on device flag is used to mark the devices (belonging to
a PM domain) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages.  Change name
of that flag to "syscore" to better reflect its purpose.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NMagnus Damm <damm@opensource.se>

Introduce function pm_genpd_syscore_switch() and two wrappers around
it, pm_genpd_syscore_poweroff() and pm_genpd_syscore_poweron(),
allowing the callers to let the generic PM domains framework know
that the given device is not necessary any more and its PM domain
can be turned off (the former) or that the given device will be
required immediately, so its PM domain has to be turned on (the
latter) during the system core (syscore) stage of system suspend
(or hibernation) and resume.

These functions will be used for handling devices registered as
clock sources and clock event devices that belong to PM domains.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Add a mechanism for counting references to the
struct generic_pm_domain_data object pointed to by
dev->power.subsys_data->domain_data if the device in question
belongs to a generic PM domain.

This change is necessary for a subsequent patch making it possible to
allocate that object from within pm_genpd_add_callbacks(), so that
drivers can attach their PM domain device callbacks to devices before
those devices are added to PM domains.

This patch has been tested on the SH7372 Mackerel board.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

On some systems there are CPU cores located in the same power
domains as I/O devices.  Then, power can only be removed from the
domain if all I/O devices in it are not in use and the CPU core
is idle.  Add preliminary support for that to the generic PM domains
framework.

First, the platform is expected to provide a cpuidle driver with one
extra state designated for use with the generic PM domains code.
This state should be initially disabled and its exit_latency value
should be set to whatever time is needed to bring up the CPU core
itself after restoring power to it, not including the domain's
power on latency.  Its .enter() callback should point to a procedure
that will remove power from the domain containing the CPU core at
the end of the CPU power transition.

The remaining characteristics of the extra cpuidle state, referred to
as the "domain" cpuidle state below, (e.g. power usage, target
residency) should be populated in accordance with the properties of
the hardware.

Next, the platform should execute genpd_attach_cpuidle() on the PM
domain containing the CPU core.  That will cause the generic PM
domains framework to treat that domain in a special way such that:

 * When all devices in the domain have been suspended and it is about
   to be turned off, the states of the devices will be saved, but
   power will not be removed from the domain.  Instead, the "domain"
   cpuidle state will be enabled so that power can be removed from
   the domain when the CPU core is idle and the state has been chosen
   as the target by the cpuidle governor.

 * When the first I/O device in the domain is resumed and
   __pm_genpd_poweron(() is called for the first time after
   power has been removed from the domain, the "domain" cpuidle
   state will be disabled to avoid subsequent surprise power removals
   via cpuidle.

The effective exit_latency value of the "domain" cpuidle state
depends on the time needed to bring up the CPU core itself after
restoring power to it as well as on the power on latency of the
domain containing the CPU core.  Thus the "domain" cpuidle state's
exit_latency has to be recomputed every time the domain's power on
latency is updated, which may happen every time power is restored
to the domain, if the measured power on latency is greater than
the latency stored in the corresponding generic_pm_domain structure.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: NKevin Hilman <khilman@ti.com>

The generic PM domains core code currently requires domains to be in
the "power on" state for adding devices to them, but this limitation
turns out to be inconvenient in some situations, so remove it.

For this purpose, make __pm_genpd_add_device() set the device's
need_restore flag if the domain is in the "power off" state, so that
the device's "restore state" (usually .runtime_resume()) callback
is executed when it is resumed after the domain has been turned on.
If the domain is in the "power on" state, the device's need_restore
flag will be cleared by __pm_genpd_add_device(), so that its "save
state" (usually .runtime_suspend()) callback is executed when the
domain is about to be turned off.  However, since that default
behavior need not be always desirable, add a helper function
pm_genpd_dev_need_restore() allowing a device's need_restore flag
to be set/unset at any time.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>