OPP: Rename 'rate_clk_single'

The field's name isn't clear enough. Rename it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Move dev_pm_opp_icc_bw to internal opp.h

It isn't used by any driver or API, privatize it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Call dev_pm_opp_set_opp() for required OPPs

Configuring the required OPP was never properly implemented, we just
took an exception for genpds and configured them directly, while leaving
out all other required OPP types.

Now that a standard call to dev_pm_opp_set_opp() takes care of
configuring the opp->level too, the special handling for genpds can be
avoided by simply calling dev_pm_opp_set_opp() for the required OPPs,
which shall eventually configure the corresponding level for genpds.

This also makes it possible for us to configure other type of required
OPPs (no concrete users yet though), via the same path. This is how
other frameworks take care of parent nodes, like clock, regulators, etc,
where we recursively call the same helper.

In order to call dev_pm_opp_set_opp() for the virtual genpd devices,
they must share the OPP table of the genpd. Call _add_opp_dev() for them
to get that done.

This commit also extends the struct dev_pm_opp_config to pass required
devices, for non-genpd cases, which can be used to call
dev_pm_opp_set_opp() for the non-genpd required devices.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Remove genpd_virt_dev_lock

All the config operations for OPP tables share common code paths now and
none of the other ones have such protection in place. Either all should
have it or none.

The understanding here is that user won't clear the OPP configs while
still using them and so such a case won't happen. We can always come
back and use a wider lock for all resource types if required.

Also fix the error on failing to allocate memory.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

OPP: Add dev_pm_opp_add_dynamic() to allow more flexibility

The dev_pm_opp_add() API is limited to add dynamic OPPs with a frequency
and a voltage level. To enable more flexibility, let's add a new API,
dev_pm_opp_add_dynamic() that's takes a struct dev_pm_opp_data* instead of
a list of in-parameters.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Simplify the over-designed pstate <-> level dance

While adding support for "performance states" in the OPP and genpd core,
it was decided to set the `pstate` field via genpd's
pm_genpd_opp_to_performance_state() helper, to allow platforms to set
`pstate` even if they don't have a corresponding `level` field in the DT
OPP tables (More details are present in commit 6e41766a6a50 ("PM /
Domain: Implement of_genpd_opp_to_performance_state()")).

Revisiting that five years later clearly suggests that it was
over-designed as all current users are eventually using the `level`
value only.

The previous commit already added necessary checks to make sure pstate
is only used for genpd tables. Lets now simplify this a little, and use
`level` directly and remove `pstate` field altogether.

Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

OPP: don't drop performance constraint on OPP table removal

This code was added (long back) by commit 009acd196fc8 ("PM / OPP:
Support updating performance state of device's power domain") and at
that time the `opp->pstate` field was used to store the performance
state required by a device's OPP.

Over time that changed and the `->pstate` field is now used only for
genpd devices and consumer devices access that via the required-opps
instead.

Because of all these changes, _opp_table_kref_release() now drops the
constraint only when the genpd's OPP table gets freed and not the
device's. Which is definitely not what we wanted. And dropping the
constraint doesn't have much meaning as the genpd itself is going away.

Moreover, if we want to drop constraints here, then just dropping the
performance constraint alone isn't sufficient as there are other
resource constraints like clk, regulator, etc. too, which must be
handled.

Probably the right thing to do here is to leave this decision to the
consumers, which can call `dev_pm_opp_set_rate(dev, 0)` or similar APIs
to drop all constraints properly. Which many of the consumers already
do.

Remove the special code, which is broken anyway.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

OPP: Staticize `lazy_opp_tables` in of.c

`lazy_opp_tables` is only used in of.c, move it there and mark it
`static`.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Move required opps configuration to specialized callback

The required-opps configuration is closely tied to genpd and performance
states at the moment and it is not very obvious that required-opps can
live without genpds. Though we don't support configuring required-opps
for non-genpd cases currently.

This commit aims at separating these parts, where configuring genpds
would be a special case of configuring the required-opps.

Add a specialized callback, set_required_opps(), to the opp table and
set it to different callbacks accordingly.

This shouldn't result in any functional changes for now.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

OPP: Don't drop opp->np reference while it is still in use

The struct dev_pm_opp contains a reference of the DT node, opp->np,
throughout its lifetime. We should increase the refcount for the same
from _opp_add_static_v2(), and drop it while removing the OPP finally.

Signed-off-by: Liang He <windhl@126.com>
[ Viresh: Updated subject / commit log, create _of_clear_opp() and drop
reference from it]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Allow multiple clocks for a device

This patch adds support to allow multiple clocks for a device.

The design is pretty much similar to how this is done for regulators,
and platforms can supply their own version of the config_clks() callback
if they have multiple clocks for their device. The core manages the
calls via opp_table->config_clks() eventually.

We have kept both "clk" and "clks" fields in the OPP table structure and
the reason is provided as a comment in _opp_set_clknames(). The same
isn't done for "rates" though and we use rates[0] at most of the places
now.

Co-developed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Make dev_pm_opp_set_opp() independent of frequency

dev_pm_opp_set_opp() can be called for any device, it may or may not
have a frequency value associated with it.

If a frequency value isn't available, we pass 0 to _set_opp(). Make it
optional instead by making _set_opp() accept a pointer instead, as the
frequency value is anyway available in the OPP. This makes
dev_pm_opp_set_opp() and _set_opp() completely independent of any
special key value.

Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Remove rate_not_available parameter to _opp_add()

commit 32715be4fe95 ("opp: Fix adding OPP entries in a wrong order if
rate is unavailable") removed the only user of this field, get rid of
rest of it now.

Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Remove custom OPP helper support

The only user of the custom helper is migrated to use
dev_pm_opp_set_config_regulators() interface. Remove the now unused
custom OPP helper support.

This cleans up _set_opp() and leaves a single code path to be used by
all users.

Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Add support for config_regulators() helper

Extend the dev_pm_opp_set_config() interface to allow adding
config_regulators() helpers. This helper will be called to set the
voltages of the regulators from the regular path in _set_opp(), while we
are trying to change the OPP.

This will eventually replace the custom set_opp() helper.

Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Add dev_pm_opp_set_config() and friends

The OPP core already have few configuration specific APIs and it is
getting complex or messy for both the OPP core and its users.

Lets introduce a new set of API which will be used for all kind of
different configurations, and shall eventually be used by all the
existing ones.

The new API, returns a unique token instead of a pointer to the OPP
table, which allows the OPP core to drop the resources selectively later
on.

Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Track if clock name is configured by platform

Track if the clock name is configured by the platform or not. This is a
preparatory change and will be used by later commits. This also makes
the behavior of the clkname API similar to other ones, which allow
repeated calls to the same API for each CPU.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Expose of-node's name in debugfs

It is difficult to find which OPPs are active at the moment, specially
if there are multiple OPPs with same frequency available in the device
tree (controlled by supported hardware feature).

Expose name of the DT node to find out the exact OPP.

While at it, also expose level field.

Reported-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Don't drop extra references to OPPs accidentally

We are required to call dev_pm_opp_put() from outside of the
opp_table->lock as debugfs removal needs to happen lock-less to avoid
circular dependency issues.

commit cf1fac943c63 ("opp: Reduce the size of critical section in
_opp_kref_release()") tried to fix that introducing a new routine
_opp_get_next() which keeps returning OPPs that can be freed by the
callers and this routine shall be called without holding the
opp_table->lock.

Though the commit overlooked the fact that the OPPs can be referenced by
other users as well and this routine will end up dropping references
which were taken by other users and hence freeing the OPPs prematurely.

In effect, other users of the OPPs will end up having invalid pointers
at hand. We didn't see any crash reports earlier as the exact situation
never happened, though it is certainly possible.

We need a way to mark which OPPs are no longer referenced by the OPP
core, so we don't drop extra references to them accidentally.

This commit adds another OPP flag, "removed", which is used to track
this. And now we should never end up dropping extra references to the
OPPs.

Cc: v5.11+ <stable@vger.kernel.org> # v5.11+
Fixes: cf1fac943c63 ("opp: Reduce the size of critical section in _opp_kref_release()")
Signed-off-by: Beata Michalska <beata.michalska@arm.com>
[ Viresh: Almost rewrote entire patch, added new "removed" field,
rewrote commit log and added the correct Fixes tag. ]
Co-developed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Don't skip freq update for different frequency

We skip the OPP update if the current and target OPPs are same. This is
fine for the devices that don't support frequency but may cause issues
for the ones that need to program frequency.

An OPP entry doesn't really signify a single operating frequency but
rather the highest frequency at which the other properties of the OPP
entry apply. And we may reach here with different frequency values,
while all of them would point to the same OPP entry in the OPP table.

We just need to update the clock frequency in that case, though in order
to not add special exit points we reuse the code flow from a normal
path.

While at it, rearrange the conditionals in the 'if' statement to check
'enabled' flag at the end.

Fixes: 81c4d8a3c414 ("opp: Keep track of currently programmed OPP")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
[ Viresh: Improved commit log and subject, rename current_freq as
current_rate, document it, remove local variable and rearrange
code. ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Allow lazy-linking of required-opps

The OPP core currently requires the required opp tables to be available
before the dependent OPP table is added, as it needs to create links
from the dependent OPP table to the required ones. This may not be
convenient for all the platforms though, as this requires strict
ordering for probing the drivers.

This patch allows lazy-linking of the required-opps. The OPP tables for
which the required-opp-tables aren't available at the time of their
initialization, are added to a special list of OPP tables:
lazy_opp_tables. Later on, whenever a new OPP table is registered with
the OPP core, we check if it is required by an OPP table in the pending
list; if yes, then we complete the linking then and there.

An OPP table is marked unusable until the time all its required-opp
tables are available. And if lazy-linking fails for an OPP table, the
OPP core disables all of its OPPs to make sure no one can use them.

Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Keep track of currently programmed OPP

The dev_pm_opp_set_rate() helper needs to know the currently programmed
OPP to make few decisions and currently we try to find it on every
invocation of this routine.

Lets start keeping track of the current_opp programmed for the devices
of the opp table, that will be quite useful going forward.

If we fail to find the current OPP, we pick the first one available in
the list, as the list is in ascending order of frequencies, level, or
bandwidth and that's the best guess we can make anyway.

Note that we used to do the frequency comparison a bit early in
dev_pm_opp_set_rate() previously, and now instead we check the target
opp, which shall be more accurate anyway.

We need to make sure that current_opp's memory doesn't get freed while
it is being used and so we keep a reference of it until the time it is
used.

Now that current_opp will always be set, we can drop some unnecessary
checks as well.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

opp: Prepare for ->set_opp() helper to work without regulators

Until now the ->set_opp() helper (i.e. special implementation for
setting the OPPs for platforms) was implemented only to take care of
multiple regulators case, but going forward we would need that for other
use cases as well.

This patch prepares for that by allocating the regulator specific part
from dev_pm_opp_set_regulators() and the opp helper part from
dev_pm_opp_register_set_opp_helper().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

opp: Defer acquiring the clk until OPPs are added

We acquire the clk at the time the OPP table is allocated, though it
works fine, it is not the best place to do so. One of the main reason
being we may need to acquire it again from dev_pm_opp_set_clkname() if
the platform wants another clock to be acquired instead.

There is also requirement from some of the platforms where they do not
want the OPP core to manage the clock at all.

This patch hence defers acquiring the clk until the time we are certain
about which clk we need to acquire and if we really need to acquire one.
With this commit, the clk will get acquired either from
dev_pm_opp_set_clkname() or while we initialize the OPPs within the
table.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

opp: Staticize _add_opp_table()

_add_opp_table() isn't used outside of core.c, mark it static.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Don't create an OPP table from dev_pm_opp_get_opp_table()

It has been found that some users (like cpufreq-dt and others on LKML)
have abused the helper dev_pm_opp_get_opp_table() to create the OPP
table instead of just finding it, which is the wrong thing to do. This
routine was meant for OPP core's internal working and exposed the whole
functionality by mistake.

Change the scope of dev_pm_opp_get_opp_table() to only finding the
table. The internal helpers _opp_get_opp_table*() are thus renamed to
_add_opp_table*(), dev_pm_opp_get_opp_table_indexed() is removed (as we
don't need the index field for finding the OPP table) and so the only
user, genpd, is updated.

Note that the prototype of _add_opp_table() was already left in opp.h by
mistake when it was removed earlier and so we weren't required to add it
now.

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Don't drop reference for an OPP table that was never parsed

dev_pm_opp_remove_table() should drop a reference to the OPP table only
if the DT OPP table was parsed earlier with a call to
dev_pm_opp_of_add_table() earlier. Else it may end up dropping the
reference to the OPP table, which was added as a result of other calls
like dev_pm_opp_set_clkname(). And would hence result in undesirable
behavior later on when caller would try to free the resource again.

Fixes: 03758d60265c ("opp: Replace list_kref with a local counter")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Remove _dev_pm_opp_find_and_remove_table() wrapper

Remove the unnecessary wrapper and merge
_dev_pm_opp_find_and_remove_table() with dev_pm_opp_remove_table().

Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Rename regulator_enabled and use it as status of all resources

Expand the scope of the regulator_enabled flag and use it to track
status of all the resources. This will be used for other stuff in the
next patch.

Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: core: add regulators enable and disable

Add enable regulators to dev_pm_opp_set_regulators() and disable
regulators to dev_pm_opp_put_regulators(). Even if bootloader
leaves regulators enabled, they should be enabled in kernel in
order to increase the reference count.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Clément Péron <peron.clem@gmail.com>
Tested-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
[ Viresh: Enable the regulator only after it is programmed and add a
flag to track its status. ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Add support for parsing interconnect bandwidth

The OPP bindings now support bandwidth values, so add support to parse it
from device tree and store it into the new dev_pm_opp_icc_bw struct, which
is part of the dev_pm_opp.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
[ Viresh: Create _read_bw() and use it, renamed _of_find_icc_paths() to
dev_pm_opp_of_find_icc_paths(), exported it and made opp_table
argument optional. Also drop the depends on from Kconfig. ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Add helpers for reading the binding properties

The opp-hz DT property is not mandatory and we may use another property
as a key in the OPP table. Add helper functions to simplify the reading
and comparing the keys.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
[ Viresh: Removed an unnecessary comment ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

opp: Replace list_kref with a local counter

A kref or refcount isn't the right tool to be used here for counting
number of devices that are sharing the static OPPs created for the OPP
table. For example, we are reinitializing the kref again, after it
reaches a value of 0 and frees the resources, if the static OPPs get
added for the same OPP table structure (as the OPP table structure was
never freed). That is messy and very unclear.

This patch makes parsed_static_opps an unsigned integer and uses it to
count the number of users of the static OPPs. The increment and
decrement to parsed_static_opps is done under opp_table->lock now to
make sure no races are possible if the OPP table is getting added and
removed in parallel (which doesn't happen in practice, but can in
theory).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

opp: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Cc: Viresh Kumar <vireshk@kernel.org>
Cc: Nishanth Menon <nm@ti.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-pm@vger.kernel.org
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Add support for parsing the 'opp-level' property

Now that the OPP bindings are updated to include an optional
'opp-level' property, add support to parse it from device tree
and store it as part of dev_pm_opp structure.
Also add and export an helper 'dev_pm_opp_get_level()' that can be
used to get the level value read from device tree when present.

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

OPP: Fix missing debugfs supply directory for OPPs

There is one case where we may end up with no "supply" directory for the
OPPs in debugfs. That happens when the OPP core isn't managing the
regulators for the device and the device's OPP do have microvolt
property. It happens because the opp_table->regulator_count remains set
to 0 and the debugfs routines don't add any supply directory in such a
case.

This commit fixes that by setting opp_table->regulator_count to 1 in
that particular case. But to make everything work nicely and not break
other parts of the core, regulator_count is defined as "int" now instead
of "unsigned int" and it can have different special values now. It is
set to -1 initially to mark it "uninitialized" and later only we set it
to 0 or positive values after checking how many supplies are there.

This also helps in finding the bugs where only few of the OPPs have the
"opp-microvolt" property set and not all.

Fixes: 1fae788ed640 ("PM / OPP: Don't create debugfs "supply-0" directory unnecessarily")
Reported-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Add dev_pm_opp_{set|put}_genpd_virt_dev() helper

Multiple generic power domains for a consumer device are supported with
the help of virtual devices, which are created for each consumer device
- genpd pair. These are the device structures which are attached to the
power domain and are required by the OPP core to set the performance
state of the genpd.

The helpers added by this commit are required to be called once for each
of these virtual devices. These are required only if multiple domains
are available for a device, otherwise the actual device structure will
be used instead by the OPP core.

The new helpers also support the complex cases where the consumer device
wouldn't always require all the domains. For example, a camera may
require only one power domain during normal operations but two during
high resolution operations. The consumer driver can call
dev_pm_opp_put_genpd_virt_dev(high_resolution_genpd_virt_dev) if it is
currently operating in the normal mode and doesn't have any performance
requirements from the genpd which manages high resolution power
requirements. The consumer driver can later call
dev_pm_opp_set_genpd_virt_dev(high_resolution_genpd_virt_dev) once it
switches back to the high resolution mode.

The new helpers differ from other OPP set/put helpers as the new ones
can be called with OPPs initialized for the table as we may need to call
them on the fly because of the complex case explained above. For this
reason it is possible that the genpd virt_dev structure may be used in
parallel while the new helpers are running and a new mutex is added to
protect against that. We didn't use the existing opp_table->lock mutex
as that is widely used in the OPP core and we will need this lock in the
dev_pm_opp_set_rate() helper while changing OPP and we need to make sure
there is not much contention while doing that as that's the hotpath.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Populate OPPs from "required-opps" property

An earlier commit populated the OPP tables from the "required-opps"
property, this commit populates the individual OPPs. This is repeated
for each OPP in the OPP table and these populated OPPs will be used by
later commits.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Populate required opp tables from "required-opps" property

The current implementation works only for the case where a single
phandle is present in the "required-opps" property, while DT allows
multiple phandles to be present there.

This patch adds new infrastructure to parse all the phandles present in
"required-opps" property and save pointers of the required OPP's OPP
tables. These will be used by later commits.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Identify and mark genpd OPP tables

We need to handle genpd OPP tables differently, this is already the case
at one location and will be extended going forward. Add another field to
the OPP table to check if the table belongs to a genpd or not.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Prevent creating multiple OPP tables for devices sharing OPP nodes

When two or more devices are sharing their clock and voltage rails, they
share the same OPP table. But there are some corner cases where the OPP
core incorrectly creates separate OPP tables for them.

For example, CPU 0 and 1 share clock/voltage rails. The platform
specific code calls dev_pm_opp_set_regulators() for CPU0 and the OPP
core creates an OPP table for it (the individual OPPs aren't initialized
as of now). The same is repeated for CPU1 then. Because
_opp_get_opp_table() doesn't compare DT node pointers currently, it
fails to find the link between CPU0 and CPU1 and so creates a new OPP
table.

Fix this by calling _managed_opp() from _opp_get_opp_table().
_managed_opp() gain an additional argument (index) to get the right node
pointer. This resulted in simplifying code in _of_add_opp_table_v2() as
well.

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Use a single mechanism to free the OPP table

Currently there are two separate ways to free the OPP table based on how
it is created in the first place.

We call _dev_pm_opp_remove_table() to free the static and/or dynamic
OPP, OPP list devices, etc. This is done for the case where the OPP
table is added while initializing the OPPs, like via the path
dev_pm_opp_of_add_table().

We also call dev_pm_opp_put_opp_table() in some cases which eventually
frees the OPP table structure once the reference count reaches 0. This
is used by the first case as well as other cases like
dev_pm_opp_set_regulators() where the OPPs aren't necessarily
initialized at this point.

This whole thing is a bit unclear and messy and obstruct any further
cleanup/fixup of OPP core.

This patch tries to streamline this by keeping a single path for OPP
table destruction, i.e. dev_pm_opp_put_opp_table().

All the cleanup happens in _opp_table_kref_release() now after the
reference count reaches 0. _dev_pm_opp_remove_table() is removed as it
isn't required anymore.

We don't drop the reference to the OPP table after creating it from
_of_add_opp_table_v{1|2}() anymore and the same is dropped only when we
try to remove them.

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()

Only one platform was depending on this feature and it is already
updated now. Stop removing dynamic OPPs from _dev_pm_opp_remove_table().
This simplifies lot of paths and removes unnecessary parameters.

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Create separate kref for static OPPs list

The static OPPs don't always get freed with the OPP table, it can happen
before that as well. For example, if the OPP table is first created
using helpers like dev_pm_opp_set_supported_hw() and the OPPs are
created at a later point. Now when the OPPs are removed, the OPP table
stays until the time dev_pm_opp_put_supported_hw() is called.

Later patches will streamline the freeing of OPP table and that requires
the static OPPs to get freed with help of a separate kernel reference.
This patch prepares for that by creating a separate kref for static OPPs
list.

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Parse OPP table's DT properties from _of_init_opp_table()

Parse the DT properties present in the OPP table from
_of_init_opp_table(), which is a dedicated routine for DT parsing.

Minor relocation of helpers is required for this.

It is possible now for _managed_opp() to return a partially initialized
OPP table if the OPP table is created via the helpers like
dev_pm_opp_set_supported_hw() and we need another flag to indicate if
the static OPP are already parsed or not to make sure we don't
incorrectly skip initializing the static OPPs.

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Pass index to _of_init_opp_table()

This is a preparatory patch required for the next commit which will
start using OPP table's node pointer in _of_init_opp_table(), which
requires the index in order to read the OPP table's phandle.

This commit adds the index argument in the call chains in order to get
it delivered to _of_init_opp_table().

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Protect dev_list with opp_table lock

The dev_list needs to be protected with a lock, else we may have
simultaneous access (addition/removal) to it and that would be racy.
Extend scope of the opp_table lock to protect dev_list as well.

Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

OPP: Don't try to remove all OPP tables on failure

dev_pm_opp_of_cpumask_add_table() creates the OPP table for all CPUs
present in the cpumask and on errors it should revert all changes it has
done.

It actually is doing a bit more than that. On errors, it tries to free
all the OPP tables, even the one it hasn't created yet. This may also
end up freeing the OPP tables which were created from separate path,
like dev_pm_opp_set_supported_hw().

Reported-and-tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

PM / OPP: Remove dev_pm_opp_{un}register_get_pstate_helper()

These helpers aren't used anymore, remove them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / OPP: Implement of_dev_pm_opp_find_required_opp()

A device's DT node or its OPP nodes can contain a phandle to other
device's OPP node, in the "required-opps" property.

This patch implements a routine to find that required OPP from the node
that contains the "required-opps" property.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / OPP: "opp-hz" is optional for power domains

"opp-hz" property is optional for power domains now and we shouldn't
error out if it is missing for power domains.

This patch creates two new routines, _get_opp_count() and
_opp_is_duplicate(), by separating existing code from their parent
functions. Also skip duplicate OPP check for power domain OPPs as they
may not have any the "opp-hz" field, but a platform specific performance
state binding to uniquely identify OPP nodes.

By default the debugfs OPP nodes are named using the "rate" value, but
that isn't possible for the power domain OPP nodes and hence they use
the index of the OPP node in the OPP node list instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / OPP: Add dev_pm_opp_{un}register_get_pstate_helper()

This adds the dev_pm_opp_{un}register_get_pstate_helper() helper
routines which will be used to set the get_pstate() callback for a
device. This callback will be later called internally by the OPP core to
get performance state corresponding to an OPP.

This is required temporarily until the time we have proper DT bindings
to include the performance state information.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / OPP: Support updating performance state of device's power domain

The genpd framework now provides an API to request device's power
domain to update its performance state. Use that interface from the
OPP core for devices whose power domains support performance states.

Note that this commit doesn't add any mechanism by which performance
states are made available to the OPP core. That would be done by a
later commit.

Note that the current implementation is restricted to the case where
the device doesn't have separate regulators for itself. We shouldn't
over engineer the code before we have real use case for them. We can
always come back and add more code to support such cases later on.

Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / OPP: Move the OPP directory out of power/

The drivers/base/power/ directory is special and contains code related
to power management core like system suspend/resume, hibernation, etc.
It was fine to keep the OPP code inside it when we had just one file for
it, but it is growing now and already has a directory for itself.

Lets move it directly under drivers/ directory, just like cpufreq and
cpuidle.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>