PM / OPP: Add reference counting helpers for Rust implementation

To ensure that resources such as OPP tables or OPP nodes are not freed
while in use by the Rust implementation, it is necessary to in

PM / OPP: Add reference counting helpers for Rust implementation

To ensure that resources such as OPP tables or OPP nodes are not freed
while in use by the Rust implementation, it is necessary to increment
their reference count from Rust code.

This commit introduces a new helper function,
dev_pm_opp_get_opp_table_ref(), to increment the reference count of an
OPP table and declares the existing helper dev_pm_opp_get() in pm_opp.h.

Signed-off-by: Viresh Kumar <[email protected]>

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OPP: Drop redundant *_opp_attach|detach_genpd()

All users of *_opp_attach|detach_genpd(), have been converted to use
dev|devm_pm_domain_attach|detach_list(), hence let's drop it along with its
corre

OPP: Drop redundant *_opp_attach|detach_genpd()

All users of *_opp_attach|detach_genpd(), have been converted to use
dev|devm_pm_domain_attach|detach_list(), hence let's drop it along with its
corresponding exported functions.

Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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OPP: Rework _set_required_devs() to manage a single device per call

At this point there are no consumer drivers that makes use of
_set_required_devs(), hence it should be straightforward to rework t

OPP: Rework _set_required_devs() to manage a single device per call

At this point there are no consumer drivers that makes use of
_set_required_devs(), hence it should be straightforward to rework the code
to enable it to better integrate with the PM domain attach procedure.

During attach, one device at the time is being hooked up to its
corresponding PM domain. Therefore, let's update the _set_required_devs()
to align to this behaviour, allowing callers to fill out one required_dev
per call. Subsequent changes starts making use of this.

Signed-off-by: Ulf Hansson <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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OPP: Remove unused declarations in header file

The definition of _update_set_required_opps() has been removed since
commit e37440e7e2c2 ("OPP: Call dev_pm_opp_set_opp() for required
OPPs").

Besides

OPP: Remove unused declarations in header file

The definition of _update_set_required_opps() has been removed since
commit e37440e7e2c2 ("OPP: Call dev_pm_opp_set_opp() for required
OPPs").

Besides, the definition of _put_opp_list_kref() has been removed since
commit 03758d60265c ("opp: Replace list_kref with a local counter").
Let's remove the empty declarations in header file.

Signed-off-by: Zhang Zekun <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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OPP: Rename 'rate_clk_single'

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

Signed-off-by: Viresh Kumar <[email protected]>

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 <[email protected]>

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

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 <[email protected]>
Tested-by: Stephan Gerhold <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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

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 <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>

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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

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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_p

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>

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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
th

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 <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>

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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 <[email protected]>

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-o

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 <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>

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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
f

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 <[email protected]>
[ Viresh: Updated subject / commit log, create _of_clear_opp() and drop
reference from it]
Signed-off-by: Viresh Kumar <[email protected]>

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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

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 <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Tested-by: Jon Hunter <[email protected]>
Tested-by: Dmitry Osipenko <[email protected]>
Tested-by: Manivannan Sadhasivam <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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 av

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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
res

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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 clean

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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 regula

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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 s

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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 b

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 <[email protected]>

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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 b

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 <[email protected]>
Tested-by: Leo Yan <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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 depe

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+ <[email protected]> # v5.11+
Fixes: cf1fac943c63 ("opp: Reduce the size of critical section in _opp_kref_release()")
Signed-off-by: Beata Michalska <[email protected]>
[ Viresh: Almost rewrote entire patch, added new "removed" field,
rewrote commit log and added the correct Fixes tag. ]
Co-developed-by: Viresh Kumar <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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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

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 <[email protected]>
[ 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 <[email protected]>

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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 depende

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 <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>

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