There is no need to check if the cpufreq driver implements callback
cpufreq_driver::target_index. The logic in the __resolve_freq uses
the frequency table available in the policy. It doesn't matter if the
driver provides 'target_index' or 'target' callback. It just has to
populate the 'policy->freq_table'.

Thus, check only frequency table during the frequency resolving call.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull cpufreq/ARM updates for 5.20-rc1 from Viresh Kumar:

"- Fix return error code in mtk_cpu_dvfs_info_init (Yang Yingliang).

 - Minor cleanups and support for new boards for Qcom cpufreq drivers
   (Bryan O'Donoghue, Konrad Dybcio, Pierre Gondois, and Yicong Yang).

 - Fix sparse warnings for Tegra driver (Viresh Kumar)."

* tag 'cpufreq-arm-updates-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
  cpufreq: tegra194: Staticize struct tegra_cpufreq_soc instances
  dt-bindings: cpufreq: cpufreq-qcom-hw: Add SM6375 compatible
  dt-bindings: opp: Add msm8939 to the compatible list
  dt-bindings: opp: Add missing compat devices
  dt-bindings: opp: opp-v2-kryo-cpu: Fix example binding checks
  cpufreq: Change order of online() CB and policy->cpus modification
  cpufreq: qcom-hw: Remove deprecated irq_set_affinity_hint() call
  cpufreq: qcom-hw: Disable LMH irq when disabling policy
  cpufreq: qcom-hw: Reset cancel_throttle when policy is re-enabled
  cpufreq: qcom-cpufreq-hw: use HZ_PER_KHZ macro in units.h
  cpufreq: mediatek: fix error return code in mtk_cpu_dvfs_info_init()

From a state where all policy->related_cpus are offline, putting one
of the policy's CPU back online re-activates the policy by:
 1. Calling cpufreq_driver->online()
 2. Setting the CPU in policy->cpus

qcom_cpufreq_hw_cpu_online() makes use of policy->cpus. Thus 1. and 2.
should be inverted to avoid having a policy->cpus empty. The
qcom-cpufreq-hw is the only driver affected by this.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

With the new design in place, the show() and store() callbacks check if
the policy is active or not before proceeding any further to avoid
potential races. And in order to guarantee that cpufreq_policy_free()
must be called after clearing the policy->cpus mask, i.e. by marking the
policy inactive.

In order to avoid introducing a bug around this later, print a warning
message if we end up freeing an active policy.

Also update cpufreq_online() a bit to make sure we clear the cpus mask
for each error case before calling cpufreq_policy_free().

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

This change was introduced long back by commit 4f750c930822 ("cpufreq:
Synchronize the cpufreq store_*() routines with CPU hotplug").

Since then, both cpufreq and hotplug core have been reworked and have
much better locking in place. The race mentioned in commit 4f750c930822
isn't possible anymore.

Drop the unnecessary locking.

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

Instead of specially adding a space for each CPU, except the first one,
lets add space for each of them and remove it at the end.

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

cpufreq_offline() calls offline() and exit() under the policy rwsem
But they are called outside the rwsem in cpufreq_online().

Make cpufreq_online() call offline() and exit() as well as online() and
init() under the policy rwsem to achieve a clear lock relationship.

All of the init() and online() implementations in the tree only
initialize the policy object without attempting to acquire the policy
rwsem and they won't call cpufreq APIs attempting to acquire it.

Signed-off-by: Schspa Shi <schspa@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If policy initialization fails after the sysfs files are created,
there is a possibility to end up running show()/store() callbacks
for half-initialized policies, which may have unpredictable
outcomes.

Abort show()/store() in such a case by making sure the policy is active.

Also dectivate the policy on such failures.

Signed-off-by: Schspa Shi <schspa@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently, cpufreq_remove_dev() invokes the ->exit() driver callback
without holding the policy rwsem which is inconsistent with what
happens if ->exit() is invoked directly from cpufreq_offline().

It also manipulates the real_cpus mask and removes the CPU device
symlink without holding the policy rwsem, but cpufreq_offline() holds
the rwsem around the modifications thereof.

For consistency, modify cpufreq_remove_dev() to hold the policy rwsem
until the ->exit() callback has been called (or it has been determined
that it is not necessary to call it).

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

Split the "core" part running under the policy rwsem out of
cpufreq_offline() to allow the locking in cpufreq_remove_dev() to be
rearranged more easily.

As a side-effect this eliminates the unlock label that's not needed
any more.

No expected functional impact.

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