cpufreq drivers aren't required to provide a sorted frequency table
today, and even the ones which provide a sorted table aren't handled
efficiently by cpufreq core.

This patch adds infrastructure to verify if the freq-table provided by
the drivers is sorted or not, and use efficient helpers if they are
sorted.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This routine can't fail unless the frequency table is invalid and
doesn't contain any valid entries.

Make it return the index and WARN() in case it is used for an invalid
table.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The policy already has this pointer set, use it instead.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Most of the callers of cpufreq_frequency_get_table() already have the
pointer to a valid 'policy' structure and they don't really need to go
through the per-cpu variable first and then a check to validate the
frequency, in order to find the freq-table for the policy.

Directly use the policy->freq_table field instead for them.

Only one user of that API is left after above changes, cpu_cooling.c and
it accesses the freq_table in a racy way as the policy can get freed in
between.

Fix it by using cpufreq_cpu_get() properly.

Since there are no more users of cpufreq_frequency_get_table() left, get
rid of it.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: Javi Merino <javi.merino@arm.com> (cpu_cooling.c)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The modularity of cpufreq_stats is quite problematic.

First off, the usage of policy notifiers for the initialization
and cleanup in the cpufreq_stats module is inherently racy with
respect to CPU offline/online and the initialization and cleanup
of the cpufreq driver.

Second, fast frequency switching (used by the schedutil governor)
cannot be enabled if any transition notifiers are registered, so
if the cpufreq_stats module (that registers a transition notifier
for updating transition statistics) is loaded, the schedutil governor
cannot use fast frequency switching.

On the other hand, allowing cpufreq_stats to be built as a module
doesn't really add much value.  Arguably, there's not much reason
for that code to be modular at all.

For the above reasons, make the cpufreq stats code non-modular,
modify the core to invoke functions provided by that code directly
and drop the notifiers from it.

Make the stats sysfs attributes appear empty if fast frequency
switching is enabled as the statistics will not be updated in that
case anyway (and returning -EBUSY from those attributes breaks
powertop).

While at it, clean up Kconfig help for the CPU_FREQ_STAT and
CPU_FREQ_STAT_DETAILS options.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

The 'initialized' field in struct cpufreq_governor is only used by
the conservative governor (as a usage counter) and the way that
happens is far from straightforward and arguably incorrect.

Namely, the value of 'initialized' is checked by
cpufreq_dbs_governor_init() and cpufreq_dbs_governor_exit() and
the results of those checks are passed (as the second argument) to
the ->init() and ->exit() callbacks in struct dbs_governor.  Those
callbacks are only implemented by the ondemand and conservative
governors and ondemand doesn't use their second argument at all.
In turn, the conservative governor uses it to decide whether or not
to either register or unregister a transition notifier.

That whole mechanism is not only unnecessarily convoluted, but also
racy, because the 'initialized' field of struct cpufreq_governor is
updated in cpufreq_init_governor() and cpufreq_exit_governor() under
policy->rwsem which doesn't help if one of these functions is run
twice in parallel for different policies (which isn't impossible in
principle), for example.

Instead of it, add a proper usage counter to the conservative
governor and update it from cs_init() and cs_exit() which is
guaranteed to be non-racy, as those functions are only called
under gov_dbs_data_mutex which is global.

With that in place, drop the 'initialized' field from struct
cpufreq_governor as it is not used any more.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Create a new helper to avoid code duplication across governors.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The design of the cpufreq governor API is not very straightforward,
as struct cpufreq_governor provides only one callback to be invoked
from different code paths for different purposes.  The purpose it is
invoked for is determined by its second "event" argument, causing it
to act as a "callback multiplexer" of sorts.

Unfortunately, that leads to extra complexity in governors, some of
which implement the ->governor() callback as a switch statement
that simply checks the event argument and invokes a separate function
to handle that specific event.

That extra complexity can be eliminated by replacing the all-purpose
->governor() callback with a family of callbacks to carry out specific
governor operations: initialization and exit, start and stop and policy
limits updates.  That also turns out to reduce the code size too, so
do it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Due to differences in the cpufreq core's handling of runtime CPU
offline and nonboot CPUs disabling during system suspend-to-RAM,
fast frequency switching gets disabled after a suspend-to-RAM and
resume cycle on all of the nonboot CPUs.

To prevent that from happening, move the invocation of
cpufreq_disable_fast_switch() from cpufreq_exit_governor() to
sugov_exit(), as the schedutil governor is the only user of fast
frequency switching today anyway.

That simply prevents cpufreq_disable_fast_switch() from being called
without invoking the ->governor callback for the CPUFREQ_GOV_POLICY_EXIT
event (which happens during system suspend now).

Fixes: b7898fda (cpufreq: Support for fast frequency switching)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Modify the ACPI cpufreq driver to provide a method for switching
CPU frequencies from interrupt context and update the cpufreq core
to support that method if available.

Introduce a new cpufreq driver callback, ->fast_switch, to be
invoked for frequency switching from interrupt context by (future)
governors supporting that feature via (new) helper function
cpufreq_driver_fast_switch().

Add two new policy flags, fast_switch_possible, to be set by the
cpufreq driver if fast frequency switching can be used for the
given policy and fast_switch_enabled, to be set by the governor
if it is going to use fast frequency switching for the given
policy.  Also add a helper for setting the latter.

Since fast frequency switching is inherently incompatible with
cpufreq transition notifiers, make it possible to set the
fast_switch_enabled only if there are no transition notifiers
already registered and make the registration of new transition
notifiers fail if fast_switch_enabled is set for at least one
policy.

Implement the ->fast_switch callback in the ACPI cpufreq driver
and make it set fast_switch_possible during policy initialization
as appropriate.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Move definitions of symbols related to transition latency and
sampling rate to include/linux/cpufreq.h so they can be used by
(future) goverernors located outside of drivers/cpufreq/.

No functional changes.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Move definitions and function headers related to struct gov_attr_set
to include/linux/cpufreq.h so they can be used by (future) goverernors
located outside of drivers/cpufreq/.

No functional changes.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Create cpufreq.c under kernel/sched/ and move the cpufreq code
related to the scheduler to that file and to sched.h.

Redefine cpufreq_update_util() as a static inline function to avoid
function calls at its call sites in the scheduler code (as suggested
by Peter Zijlstra).

Also move the definition of struct update_util_data and declaration
of cpufreq_set_update_util_data() from include/linux/cpufreq.h to
include/linux/sched.h.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>

The entire sequence of events (like INIT/START or STOP/EXIT) for which
cpufreq_governor() is called, is guaranteed to be protected by
policy->rwsem now.

The additional checks that were added earlier (as we were forced to drop
policy->rwsem before calling cpufreq_governor() for EXIT event), aren't
required anymore.

Over that, they weren't sufficient really. They just take care of
START/STOP events, but not INIT/EXIT and the state machine was never
maintained properly by them.

Kill the unnecessary checks and policy->governor_enabled field.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Earlier, when the struct freq-attr was used to represent governor
attributes, the standard cpufreq show/store sysfs attribute callbacks
were applied to the governor tunable attributes and they always acquire
the policy->rwsem lock before carrying out the operation.  That could
have resulted in an ABBA deadlock if governor tunable attributes are
removed under policy->rwsem while one of them is being accessed
concurrently (if sysfs attributes removal wins the race, it will wait
for the access to complete with policy->rwsem held while the attribute
callback will block on policy->rwsem indefinitely).

We attempted to address this issue by dropping policy->rwsem around
governor tunable attributes removal (that is, around invocations of the
->governor callback with the event arg equal to CPUFREQ_GOV_POLICY_EXIT)
in cpufreq_set_policy(), but that opened up race conditions that had not
been possible with policy->rwsem held all the time.

The previous commit, "cpufreq: governor: New sysfs show/store callbacks
for governor tunables", fixed the original ABBA deadlock by adding new
governor specific show/store callbacks.

We don't have to drop rwsem around invocations of governor event
CPUFREQ_GOV_POLICY_EXIT anymore, and original fix can be reverted now.

Fixes: 955ef483 (cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT)
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reported-by: NJuri Lelli <juri.lelli@arm.com>
Tested-by: NJuri Lelli <juri.lelli@arm.com>
Tested-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Introduce a mechanism by which parts of the cpufreq subsystem
("setpolicy" drivers or the core) can register callbacks to be
executed from cpufreq_update_util() which is invoked by the
scheduler's update_load_avg() on CPU utilization changes.

This allows the "setpolicy" drivers to dispense with their timers
and do all of the computations they need and frequency/voltage
adjustments in the update_load_avg() code path, among other things.

The update_load_avg() changes were suggested by Peter Zijlstra.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NIngo Molnar <mingo@kernel.org>

That macro uses an internal static inline function that is first
totally unnecessary and second hard to read, so simplify it and
get rid of that monster.

No functional changes.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

The preprocessor magic used for setting the default cpufreq governor
(and for using the performance governor as a fallback one for that
matter) is really nasty, so replace it with __weak functions and
overrides.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Notice that the boost_supported field in struct cpufreq_driver is
redundant, because the driver's ->set_boost callback may be left
unset if "boost" is not supported.  Moreover, the only driver
populating the ->set_boost callback is acpi_cpufreq, so make it
avoid populating that callback if "boost" is not supported, rework
the core to check ->set_boost instead of boost_supported to
verify "boost" support and drop boost_supported which isn't
used any more.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

cpufreq_boost_supported() is not used outside of cpufreq.c, so make
it static.

While at it, refactor it as a one-liner (which it really is).
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

For cpufreq drivers which use setpolicy interface, after offline->online
the policy is set to default. This can be reproduced by setting the
default policy of intel_pstate or longrun to ondemand and then change to
"performance". After offline and online, the setpolicy will be called with
the policy=ondemand.

For drivers using governors this condition is handled by storing
last_governor, during offline and restoring during online. The same should
be done for drivers using setpolicy interface. Storing last_policy during
offline and restoring during online.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The cpufreq sysfs interface had been a bit inconsistent as one of the
CPUs for a policy had a real directory within its sysfs 'cpuX' directory
and all other CPUs had links to it. That also made the code a bit
complex as we need to take care of moving the sysfs directory if the CPU
containing the real directory is getting physically hot-unplugged.

Solve this by creating 'policyX' directories (per-policy) in
/sys/devices/system/cpu/cpufreq/ directory, where X is the CPU for which
the policy was first created.

This also removes the need of keeping kobj_cpu and we can remove it now.
Suggested-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NSaravana Kannan <skannan@codeaurora.org>
Acked-by: is more of a general agreement from the person that he is
Reviewed-by: is a more strict tag and implies that the reviewer has
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

They don't do anything special now, remove the unnecessary wrapper.
Reviewed-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Later patches will need to create policy specific directories in
/sys/devices/system/cpu/cpufreq/ directory and so the cpufreq directory
wouldn't be ever empty.

And so no fun creating/destroying it on need basis anymore. Create it
once on system boot.
Reviewed-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq_cpu_get() called by get_cur_freq_on_cpu() is overkill,
because the ->get() callback is always invoked in a context in
which all of the conditions checked by cpufreq_cpu_get() are
guaranteed to be satisfied.

Use cpufreq_cpu_get_raw() instead of it and drop the
corresponding cpufreq_cpu_put() from get_cur_freq_on_cpu().
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Its all about caching min/max freq requested by userspace, and
the name 'cpufreq_real_policy' doesn't fit that well. Rename it to
cpufreq_user_policy.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Its always same as policy->policy, and there is no need to keep another
copy of it. Remove it.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Its always same as policy->governor, and there is no need to keep
another copy of it. Remove it.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

What's being done from CPUFREQ_INCOMPATIBLE, can also be done with
CPUFREQ_ADJUST. There is nothing special with CPUFREQ_INCOMPATIBLE
notifier.

Kill CPUFREQ_INCOMPATIBLE and fix its usage sites.

This also updates the numbering of notifier events to remove holes.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make scaling_boost_freqs sysfs attribute is available when
cpufreq-dt driver is used and boost support is enabled.
Suggested-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In some cases it wouldn't be known at time of driver registration, if
the driver needs to support boost frequencies.

For example, while getting boost information from DT with opp-v2
bindings, we need to parse the bindings for all the CPUs to know if
turbo/boost OPPs are supported or not.

One way out to do that efficiently is to delay supporting boost mode
(i.e. creating /sys/devices/system/cpu/cpufreq/boost file), until the
time OPP bindings are parsed.

At that point, the driver can enable boost support. This can be done at
->init(), where the frequency table is created.

To do that, the driver requires few APIs from cpufreq core that let him
do this. This patch provides these APIs.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

After commit 87549141 (cpufreq: Stop migrating sysfs files on
hotplug) there is a problem with CPUs that share cpufreq policy
objects with other CPUs and are initially offline.

Say CPU1 shares a policy with CPU0 which is online and is registered
first.  As part of the registration process, cpufreq_add_dev() is
called for it.  It creates the policy object and a symbolic link
to it from the CPU1's sysfs directory.  If CPU1 is registered
subsequently and it is offline at that time, cpufreq_add_dev() will
attempt to create a symbolic link to the policy object for it, but
that link is present already, so a warning about that will be
triggered.

To avoid that warning, make cpufreq use an additional CPU mask
containing related CPUs that are actually present for each policy
object.  That mask is initialized when the policy object is populated
after its creation (for the first online CPU using it) and it includes
CPUs from the "policy CPUs" mask returned by the cpufreq driver's
->init() callback that are physically present at that time.  Symbolic
links to the policy are created only for the CPUs in that mask.

If cpufreq_add_dev() is invoked for an offline CPU, it checks the
new mask and only creates the symlink if the CPU was not in it (the
CPU is added to the mask at the same time).

In turn, cpufreq_remove_dev() drops the given CPU from the new mask,
removes its symlink to the policy object and returns, unless it is
the CPU owning the policy object.  In that case, the policy object
is moved to a new CPU's sysfs directory or deleted if the CPU being
removed was the last user of the policy.

While at it, notice that cpufreq_remove_dev() can't fail, because
its return value is ignored, so make it ignore return values from
__cpufreq_remove_dev_prepare() and __cpufreq_remove_dev_finish()
and prevent these functions from aborting on errors returned by
__cpufreq_governor().  Also drop the now unused sif argument from
them.

Fixes: 87549141 (cpufreq: Stop migrating sysfs files on hotplug)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-and-tested-by: NRussell King <linux@arm.linux.org.uk>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

In order to prepare for the next few commits, that will stop migrating
sysfs files on cpu hotplug, this patch starts managing sysfs-cpu
separately.

The behavior is still the same as we are still migrating sysfs files on
hotplug, later commits would change that.
Signed-off-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

History of which governor was used last is common to all CPUs within a
policy and maintaining it per-cpu isn't the best approach for sure.

Apart from wasting memory, this also increases the complexity of
managing this data structure as it has to be updated for all CPUs.

To make that somewhat simpler, lets store this information in a new
field 'last_governor' in struct cpufreq_policy and update it on removal
of last cpu of a policy.

As a side-effect it also solves an old problem, consider a system with
two clusters 0 & 1. And there is one policy per cluster.

Cluster 0: CPU0 and 1.
Cluster 1: CPU2 and 3.

 - CPU2 is first brought online, and governor is set to performance
   (default as cpufreq_cpu_governor wasn't set).
 - Governor is changed to ondemand.
 - CPU2 is taken offline and cpufreq_cpu_governor is updated for CPU2.
 - CPU3 is brought online.
 - Because cpufreq_cpu_governor wasn't set for CPU3, the default governor
   performance is picked for CPU3.

This patch fixes the bug as we now have a single variable to update for
policy.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

CPUFREQ_UPDATE_POLICY_CPU notifications were used only from cpufreq-stats which
doesn't use it anymore. Remove them.

This also decrements values of other notification macros defined after
CPUFREQ_UPDATE_POLICY_CPU by 1 to remove gaps. Hopefully all users are using
macro's instead of direct numbers and so they wouldn't break as macro values are
changed now.
Reviewed-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

'last_cpu' was used only from cpufreq-stats and isn't used anymore. Get rid of
it.
Reviewed-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

All CPUs sharing a cpufreq policy share stats too. For this reason,
add a stats pointer to struct cpufreq_policy and drop per-CPU variable
cpufreq_stats_table used for accessing cpufreq stats so as to reduce
code complexity.
Reviewed-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently there is no callback for cpufreq drivers which is called once the
policy is ready to be used. There are some requirements where such a callback is
required.

One of them is registering a cooling device with the help of
of_cpufreq_cooling_register(). This routine tries to get 'struct cpufreq_policy'
for CPUs which isn't yet initialed at the time ->init() is called and so we face
issues while registering the cooling device.

Because we can't register cooling device from ->init(), we need a callback that
is called after the policy is ready to be used and hence we introduce ->ready()
callback.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NEduardo Valentin <edubezval@gmail.com>
Tested-by: NEduardo Valentin <edubezval@gmail.com>
Reviewed-by: NLukasz Majewski <l.majewski@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Adding any new callback to 'struct cpufreq_driver' gives following checkpatch
warning:

WARNING: Unnecessary space before function pointer arguments
+	void	(*ready)	(struct cpufreq_policy *policy);

This is because we have been using a tab spacing between function pointer name
and its arguments and the new one tried to follow that.

Though we normally don't try to fix every checkpatch warning, specially around
formatting issues as that creates unnecessary noise over lists. But I thought we
better fix this so that new additions don't generate these warnings plus it
looks far better/symmetric now.

So, remove these tab spacing issues in 'struct cpufreq_driver' only + fix
alignment of all members.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: NEduardo Valentin <edubezval@gmail.com>
Tested-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This commit extends the cpufreq_driver structure with an additional
'void *driver_data' field that can be filled by the ->probe() function
of a cpufreq driver to pass additional custom information to the
driver itself.

A new function called cpufreq_get_driver_data() is added to allow a
cpufreq driver to retrieve those driver data, since they are typically
needed from a cpufreq_policy->init() callback, which does not have
access to the cpufreq_driver structure. This function call is similar
to the existing cpufreq_get_current_driver() function call.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>