Mediatek MT8173 is an ARMv8 based quad-core (2*Cortex-A53 and
2*Cortex-A72) SoC with duall clusters. For each cluster, two voltage
inputs, Vproc and Vsram are supplied by two regulators. For the big
cluster, two regulators come from different PMICs. In this case, when
scaling voltage inputs of the cluster, the voltages of two regulator
inputs need to be controlled by software explicitly under the SoC
specific limitation:

	100mV < Vsram - Vproc < 200mV

which is called 'voltage tracking' mechanism. And when scaling the
frequency of cluster clock input, the input MUX need to be parented to
another "intermediate" stable PLL first and reparented to the original
PLL once the original PLL is stable at the target frequency. This patch
implements those mechanisms to enable CPU DVFS support for Mediatek
MT8173 SoC.
Signed-off-by: NPi-Cheng Chen <pi-cheng.chen@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Append more Oracle X86 servers that have their own power management,

SUN FIRE X4275 M3
SUN FIRE X4170 M3
and
SUN FIRE X6-2
Signed-off-by: NEthan Zhao <ethan.zhao@oracle.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Whitelist the SKL-S processor
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Coverity scanning performed on intel_pstate.c shows possible
overflow when doing left shifting:
val = pstate << 8;
since pstate is of type integer, while val is of u64, left shifting
pstate might lead to potential loss of upper bits. Say, if pstate equals
0x4000 0000, after pstate << 8 we will get zero assigned to val.
Although pstate will not likely be that big, this patch cast the left
operand to u64 before performing the left shift, to avoid complaining
from Coverity.
Reported-by: NCoquard, Christophe <christophe.coquard@intel.com>
Signed-off-by: NChen Yu <yu.c.chen@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This check was originally added by commit 9c9a43ed ("[CPUFREQ]
return error when failing to set minfreq").It attempt to return an error
on obviously incorrect limits when we echo xxx >.../scaling_max,min_freq
Actually we just need check if new_policy->min > new_policy->max.
Because at least one of max/min is copied from cpufreq_get_policy().

For example, when we echo xxx > .../scaling_min_freq, new_policy is
copied from policy in cpufreq_get_policy. new_policy->max is same with
policy->max. new_policy->min is set to a new value.

Let me explain it in deduction method, first statement in if ():
new_policy->min > policy->max
policy->max == new_policy->max
==> new_policy->min > new_policy->max

second statement in if():
new_policy->max < policy->min
policy->max < policy->min
==>new_policy->min > new_policy->max (induction method)

So we have proved that we only need check if new_policy->min >
new_policy->max.

After apply this patch, we can also modify ->min and ->max at same time
if new freq range is very much different from current freq range. For
example, if current freq range is 480000-960000, then we want to set
this range to 1120000-2240000, we would fail in the past because
new_policy->min > policy->max. As long as the cpufreq range is valid, we
has no reason to reject the user. So correct the check to avoid such
case.
Signed-off-by: NPan Xinhui <xinhuix.pan@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

To protect against races with concurrent CPU online/offline, call
get_online_cpus() before registering a cpufreq driver.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

The recover_policy is unsed in cpufreq_online() to indicate whether
a new policy object is created or an existing one is reinitialized.

The "recover" part of the name is slightly confusing (it should be
"reinitialization" rather than "recovery") and the logical not (!)
operator is applied to it in almost all of the checks it is used in,
so replace that variable with a new one called "new_policy" that
will be true in the case of a new policy creation.

While at it, drop one of the labels that is jumped to from only
one spot.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

To separate the CPU online interface from the CPU device
registration, split cpufreq_online() out of cpufreq_add_dev()
and make cpufreq_cpu_callback() call the former, while
cpufreq_add_dev() itself will only be used as the CPU device
addition subsystem interface callback.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Suggested-by: NRussell King <linux@arm.linux.org.uk>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

If frequency is throttled due to OCC reset then cpus will be in Psafe
frequency, so restore the frequency on all cpus to policy->cur when
OCCs are active again. And if frequency is throttled due to Pmax
capping then restore the frequency of all the cpus  in the chip on
unthrottling.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On a reset cycle of OCC, although the system retires from safe
frequency state the local pstate is not restored to Pmin or last
requested pstate. Now if the cpufreq governor initiates a pstate
change, the local pstate will be in Psafe and we will be reporting a
false positive when we are not throttled.

So in powernv_cpufreq_throttle_check() remove the condition which
checks if local pstate is less than Pmin while checking for Psafe
frequency. If the cpus are forced to Psafe then PMSR.psafe_mode_active
bit will be set. So, when OCCs become active this bit will be cleared.
Let us just rely on this bit for reporting throttling.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Re-evaluate the chip's throttled state on recieving OCC_THROTTLE
notification by executing *throttle_check() on any one of the cpu on
the chip. This is a sanity check to verify if we were indeed
throttled/unthrottled after receiving OCC_THROTTLE notification.

We cannot call *throttle_check() directly from the notification
handler because we could be handling chip1's notification in chip2. So
initiate an smp_call to execute *throttle_check(). We are irq-disabled
in the notification handler, so use a worker thread to smp_call
throttle_check() on any of the cpu in the chipmask.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

OCC is an On-Chip-Controller which takes care of power and thermal
safety of the chip. During runtime due to power failure or
overtemperature the OCC may throttle the frequencies of the CPUs to
remain within the power budget.

We want the cpufreq driver to be aware of such situations to be able
to report the reason to the user. We register to opal_message_notifier
to receive OCC messages from opal.

powernv_cpufreq_throttle_check() reports any frequency throttling and
this patch will report the reason or event that caused throttling. We
can be throttled if OCC is reset or OCC limits Pmax due to power or
thermal reasons. We are also notified of unthrottling after an OCC
reset or if OCC restores Pmax on the chip.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The On-Chip-Controller(OCC) can throttle cpu frequency by reducing the
max allowed frequency for that chip if the chip exceeds its power or
temperature limits. As Pmax capping is a chip level condition report
this throttling behavior at chip level and also do not set the global
'throttled' on Pmax capping instead set the per-chip throttled
variable. Report unthrottling if Pmax is restored after throttling.

This patch adds a structure to store chip id and throttled state of
the chip.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Change cpufreq_policy_alloc() to take a CPU number instead of a CPU
device pointer as its argument, as it is the only function called by
cpufreq_add_dev() taking a device pointer argument at this point.

That will allow us to split the CPU online part from cpufreq_add_dev()
more cleanly going forward.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

The related_cpus mask includes CPUs whose cpufreq_cpu_data per-CPU
pointers have been set the the given policy.  Since those pointers
are only set at the policy creation time and unset when the policy
is deleted, the related_cpus should not be updated between those
two operations.

For this reason, avoid updating it whenever the first of the
"related" CPUs goes online.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

The dev argument of cpufreq_add_policy_cpu() and
cpufreq_add_dev_interface() is not used by any of them,
so drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

The leftover out_release_rwsem label in cpufreq_add_dev() is not
necessary any more and confusing, so drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Notice that when cpufreq_policy_restore() is called, its per-CPU
cpufreq_cpu_data variable has been already dereferenced and if that
variable is not NULL, the policy local pointer in cpufreq_add_dev()
contains its value.

Therefore it is not necessary to dereference it again and the
policy pointer can be used directly.  Moreover, if that pointer
is not NULL, the policy is inactive (or the previous check would
have made us return from cpufreq_add_dev()) so the restoration
code from cpufreq_policy_restore() can be moved to that point
in cpufreq_add_dev().

Do that and drop cpufreq_policy_restore().
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Since __cpufreq_remove_dev_prepare() and __cpufreq_remove_dev_finish()
are about CPU offline rather than about CPU removal, rename them to
cpufreq_offline_prepare() and cpufreq_offline_finish(), respectively.

Also change their argument from a struct device pointer to a CPU
number, because they use the CPU number only internally anyway
and make them void as their return values are ignored.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

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>

Scaling for Knights Landing is same as the default scaling (100000).
When Knigts Landing support was added to the pstate driver, this
parameter was omitted resulting in a kernel panic during boot.

Fixes: b34ef932 (intel_pstate: Knights Landing support)
Reported-by: NYasuaki Ishimatsu <yishimat@redhat.com>
Signed-off-by: NDasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: NLukasz Anaczkowski <lukasz.anaczkowski@intel.com>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Cc: 4.1+ <stable@vger.kernel.org> # 4.1+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq_rwsem was introduced in commit 6eed9404 ("cpufreq: Use
rwsem for protecting critical sections) in order to replace
try_module_get() on the cpu-freq driver. That try_module_get() worked
well until the refcount was so heavily used that module removal became
more or less impossible.

Though when looking at the various (undocumented) protection
mechanisms in that code, the randomly sprinkeled around cpufreq_rwsem
locking sites are superfluous.

The policy, which is acquired in cpufreq_cpu_get() and released in
cpufreq_cpu_put() is sufficiently protected already.

  cpufreq_cpu_get(cpu)
    /* Protects against concurrent driver removal */
    read_lock_irqsave(&cpufreq_driver_lock, flags);
    policy = per_cpu(cpufreq_cpu_data, cpu);
    kobject_get(&policy->kobj);
    read_unlock_irqrestore(&cpufreq_driver_lock, flags);

The reference on the policy serializes versus module unload already:

  cpufreq_unregister_driver()
    subsys_interface_unregister()
      __cpufreq_remove_dev_finish()
        per_cpu(cpufreq_cpu_data) = NULL;
	cpufreq_policy_put_kobj()

If there is a reference held on the policy, i.e. obtained prior to the
unregister call, then cpufreq_policy_put_kobj() will wait until that
reference is dropped. So once subsys_interface_unregister() returns
there is no policy pointer in flight and no new reference can be
obtained. So that rwsem protection is useless.

The other usage of cpufreq_rwsem in show()/store() of the sysfs
interface is redundant as well because sysfs already does the proper
kobject_get()/put() pairs.

That leaves CPU hotplug versus module removal. The current
down_write() around the write_lock() in cpufreq_unregister_driver() is
silly at best as it protects actually nothing.

The trivial solution to this is to prevent hotplug across
cpufreq_unregister_driver completely.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

freq_table should be alloced in ->init and freed in ->exit, but it
it is not freed.  Fix this memory leak in acpi_cpufreq_cpu_exit().
Signed-off-by: NPan Xinhui <xinhuix.pan@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

freq_table is now stored as policy->freq_table, so drop the redundant
freq_table from struct cpufreq_acpi_io.
Signed-off-by: NPan Xinhui <xinhuix.pan@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The cpb sysfs attribute is only exposed by the ACPI cpufreq driver
after a runtime check.  For this purpose, the driver keeps a NULL
placeholder in its table of sysfs attributes and replaces the NULL
with a pointer to an attribute structure if it decides to expose
cpb.

That is confusing, so make the driver set the pointer to the cpb
attribute structure upfront and replace it with NULL if the
attribute should not be exposed instead.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

After commit 8cfcfd39 (acpi-cpufreq: Fix an ACPI perf unregister
issue) we store both a pointer to per-CPU data of the first policy
CPU and the number of that CPU which are redundant.

Since the CPU number has to be stored anyway for the unregistration,
the pointer to the CPU's per-CPU data may be dropped and we can
access the data in question via per_cpu_ptr().
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

acpi_processor_unregister_performance() actually doesn't use its
first argument, so drop it and update the callers accordingly.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Return codes aren't honored properly in cpufreq_set_policy(). This can
lead to two problems:
- wrong errors propagated to sysfs
- we try to do next state-change even if the previous one failed

cpufreq_governor_dbs() now returns proper errors on all invalid
state-transition requests and this code should honor that.
Reviewed-and-tested-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

With previous commit, governors have started to return errors on invalid
state-transition requests. We already have a WARN for an invalid
state-transition request in cpufreq_governor_dbs(). This does trigger
today, as the sequence of events isn't guaranteed by cpufreq core.

Lets stop warning on that for now, and make sure we don't enter an
invalid state.
Reviewed-and-tested-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There can be races where the request has come to a wrong state. For
example INIT followed by STOP (instead of START) or START followed by
EXIT (instead of STOP).

Address these races by making sure the state-machine never gets into
any invalid state. Also return an error if an invalid state-transition
is requested.
Reviewed-and-tested-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Some part of cs_dbs_timer() and od_dbs_timer() is exactly same and is
unnecessarily duplicated.

Create the real work-handler in cpufreq_governor.c and put the common
code in this routine (dbs_timer()).

Shouldn't make any functional change.
Reviewed-and-tested-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Some information is common to all CPUs belonging to a policy, but are
kept on per-cpu basis. Lets keep that in another structure common to all
policy->cpus. That will make updates/reads to that less complex and less
error prone.

The memory for cpu_common_dbs_info is allocated/freed at INIT/EXIT, so
that it we don't reallocate it for STOP/START sequence. It will be also
be used (in next patch) while the governor is stopped and so must not be
freed that early.
Reviewed-and-tested-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Just call it 'policy', cur_policy is unnecessarily long and doesn't
have any special meaning.
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

It is called as 'cdbs' at most of the places and 'cpu_dbs' at others.
Lets use 'cdbs' consistently for better readability.
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Its not common info to all CPUs, but a structure representing common
type of cpu info to both governor types. Lets drop 'common_' from its
name.
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Its not used at all, drop it.
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Delayed work was named as 'work' and to access work within it we do
work.work. Not much readable. Rename delayed_work as 'dwork'.
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

HWP previously was only enabled at driver load time, on the boot
CPU, however, HWP must be enabled per package. Move the code to
enable HWP to the cpufreq driver init path so that it will be
called per CPU.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Tested-by: NDavid Zhuang <david.zhuang@oracle.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fixed coding style issues found by checkpatch.pl tool. Changed
space indentation to tab, removed unneccesary braces, removed
space between MODULE macros and parentheses.

REMARKS: failed to 'make' this file with error message
'fatal error: asm/mach-types.h: No such file or directory'.
Signed-off-by: NCristian Ardelean <cristian97.ardelean@gmail.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

As policy->cpu may not be same in acpi_cpufreq_cpu_init() and
acpi_cpufreq_cpu_exit(). There is a risk that we use different CPU
to un/register ACPI performance. So acpi_processor_unregister_performance()
may not be able to do the cleanup work. That causes a memory leak. And
if there will be another acpi_processor_register_performance() call,
it may also fail thanks to the internal check of pr->performace.

So add a new struct acpi_cpufreq_data field, acpi_perf_cpu, to fix
this issue.
Signed-off-by: NPan Xinhui <xinhuix.pan@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>