There are two cases when we may try to add CPUs we're already handling:
 - On boot, the first cpu has marked all policy->cpus managed and so we
   will find policy for all other policy->cpus later on.
 - When a managed cpu is hotplugged out and later brought back in.

Currently, separate paths and checks take care of the two.  While the
first one is detected by testing cpu against 'policy->cpus', the other
one is detected by testing cpu against 'policy->related_cpus'.

We can handle them both via a single path and there is no need to do
special checking for the first one.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
[ rjw: Changelog, comments ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Simply returning here with an error is not enough. It shouldn't be allowed at
all to try calling cpufreq_cpu_get() for an invalid CPU.

Add a WARN here to make it clear that it wouldn't be acceptable at all.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq_add_dev() is an unnecessary wrapper over __cpufreq_add_dev(). Merge
them.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This clearly states what the code inside these routines is doing and how these
must be used.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The intel_pstate driver is difficult to debug and investigate without tsc.

Also, it is likely use of tsc, and some version of C0 percentage,
will be re-introdcued in futute.

There have also been occasions where it is desirebale to know, and
confirm, the previous target pstate.

This patch brings back tsc, adds previous target pstate,
and adds both to the trace data collection.
Signed-off-by: NDoug Smythies <dsmythies@telus.net>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The "cpu-cluster.<n>" used to get the cluster clock is not used by any
platform. Moreover __of_clk_get_by_name used in clk_get return error if
the "clock-names" in the DT doesn't match this string. When using DT,
it's not compulsory to specify the clock name unless there are multiple
clock input entries in the consumer.

This patch removes the unused clock string from the driver.
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The actual frequency is set through "clk_change_rate" which is void
function. If the underlying hardware fails and returns error, the error
is lost in the clk layer. In order to track such failures, we need to
read back the frequency(just the cached value as clk_recalc called after
clk->ops->set_rate gets the frequency)

This patch adds check to see if the frequency is set correctly or if
they were any hardware failures and sends the appropriate errors to the
cpufreq core.
Reviewed-by: NMichael Turquette <mike.turquette@linaro.org>
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

pxa255_run_freqs and pxa255_turbo_freqs are only read.
This patch updates arrays declaration, find_freq_tables()
and its callsites.
Suggested-by: NJoe Perches <joe@perches.com>
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

typedef is not really useful here. Replace it by structure
to improve readability. typedef should only be used in some cases.
(See Documentation/CodingStyle Chapter 5 for details).
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

I keep seeing

  drivers/cpufreq/intel_pstate.c: In function ‘intel_pstate_init’:
  drivers/cpufreq/intel_pstate.c:1187:26: warning: initialization from incompatible pointer type
    struct cpuinfo_x86 *c = &boot_cpu_data;

when doing randconfig builds.

This is caused by the fact that when !CONFIG_SMP, asm/processor.h
defines cpu_info to boot_cpu_data and the local variable

  struct cpu_defaults *cpu_info

overshadows it leading to this unfortunate assignment in the
preprocessed source:

 struct cpu_defaults *boot_cpu_data;
 struct cpuinfo_x86 *c = &boot_cpu_data;

Rename the local variable and use static_cpu_has_safe() which alleviates
the need for defining a local cpuinfo_x86 pointer.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Change the setpoint for the Baytrail and Cherrytrail CPUs.  This
will cause more aggressive pstate selection and improves
performance on a variety of workloads with little power penalty.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

 1. Add Knights Landing (KNL) CPUID to the list of CPUIDs supported by
    the intel_pstate driver.

 2. Add a new cpu_default structure for KNL since KNL has a slightly
    different mechanism to get turbo pstates from MSRs.
Signed-off-by: NDasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
[ rjw: Subject and changelog ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

x86_match_cpu will not match our cpuid unless APERF/MPERF flag is
set, so there is no need to do the manual check for this MSR.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The qoriq-cpufreq driver contains a hack for powerpc to include
asm/smp.h on uniprocessor builds so it can get the hardware CPU
number. On ARM, it does not require this hack, but instead gets
a compile error:

In file included from drivers/cpufreq/qoriq-cpufreq.c:24:0:
arch/arm/include/asm/smp.h:18:3: error: #error "<asm/smp.h> included in non-SMP build"
arch/arm/include/asm/smp.h:21:0: warning: "raw_smp_processor_id" redefined

This adds an #ifdef to mirror the one in its get_cpu_physical_id()
function.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 2f249358 ("cpufreq: qoriq: rename the driver")
Cc: Tang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

All CPUs leaving the first-online CPU are hotplugged out on suspend and
and cpufreq core stops managing them.

On resume, we need to call cpufreq_update_policy() for this CPU's policy
to make sure its frequency is in sync with cpufreq's cached value, as it
might have got updated by hardware during suspend/resume.

The policies are always added to the top of the policy-list. So, in
normal circumstances, CPU 0's policy will be the last one in the list.
And so the code checks for the last policy.

But there are cases where it will fail. Consider quad-core system, with
policy-per core. If CPU0 is hotplugged out and added back again, the
last policy will be on CPU1 :(

To fix this in a proper way, always look for the policy of the first
online CPU. That way we will be sure that we are calling
cpufreq_update_policy() for the only CPU that wasn't hotplugged out.

Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Fixes: 2f0aea93 ("cpufreq: suspend governors on system suspend/hibernate")
Reported-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add acpu driver for hisilicon SoC, acpu is application processor
subsystem. Currently the acpu has the coupled clock domain for two
clusters, so this driver will directly use cpufreq-dt driver as
backend.
Signed-off-by: NLeo Yan <leo.yan@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The power and thermal safety of the system is taken care by an
On-Chip-Controller (OCC) which is real-time subsystem embedded within
the POWER8 processor. OCC continuously monitors the memory and core
temperature, the total system power, state of power supply and fan.

The cpu frequency can be throttled by OCC for the following reasons:
1)If a processor crosses its power and temperature limit then OCC will
  lower its Pmax to reduce the frequency and voltage.
2)If OCC crashes then the system is forced to Psafe frequency.
3)If OCC fails to recover then the kernel is not allowed to do any
  further frequency changes and the chip will remain in Psafe.

The user can see a drop in performance when frequency is throttled and
is unaware of throttling. So detect and report such a condition, so
the user can check the OCC status to reboot the system or check for
power supply or fan failures.

The current status of the core is read from Power Management Status
Register(PMSR) to check if any of the throttling condition is occurred
and the appropriate throttling message is reported.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This driver works on all QorIQ platforms which include
ARM-based cores and PPC-based cores.
Rename it in order to represent better.
Signed-off-by: NTang Yuantian <Yuantian.Tang@freescale.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Freescale introduced new ARM core-based SoCs which support dynamic
frequency switch feature. DFS on new SoCs are compatible with current
PowerPC CoreNet platforms. In order to support those new platforms,
this driver needs to be updated. The main changes include:

1. Changed the names of functions in driver.
2. Added two new functions get_cpu_physical_id() and get_bus_freq().
3. Used a new way to get the CPU mask which share clock wire.
Signed-off-by: NTang Yuantian <Yuantian.Tang@freescale.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If CONFIG_SMP=n, <linux/smp.h> does not include <asm/smp.h>, causing:

drivers/cpufreq/ppc-corenet-cpufreq.c: In function 'corenet_cpufreq_cpu_init':
drivers/cpufreq/ppc-corenet-cpufreq.c:173:3: error: implicit declaration of function 'get_hard_smp_processor_id' [-Werror=implicit-function-declaration]
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit: e725d26c provided possibility to
use device tree to asses if cpu can be used as cooling device. Since the
code was somewhat awkward, simpler approach has been proposed.

Test HW: Exynos 4412 - Odroid U3.
Suggested-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NLukasz Majewski <l.majewski@samsung.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

Commit 32726d2d ("ARM: SAMSUNG: Remove legacy clock code")
already removed the callback pointer, but there was one remaining
user:

drivers/cpufreq/s3c24xx-cpufreq.c: In function 's3c_cpufreq_resume_clocks':
drivers/cpufreq/s3c24xx-cpufreq.c:149:14: error: 'struct s3c_cpufreq_info' has no member named 'resume_clocks'
  cpu_cur.info->resume_clocks();
              ^
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 32726d2d ("ARM: SAMSUNG: Remove legacy clock code")
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Cc: 3.17+ <stable@vger.kernel.org> # v3.17+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The two functions s3c2416_cpufreq_driver_init and s3c_cpufreq_register
are marked init but are called from a context that might be run after
the __init sections are discarded, as the compiler points out:

WARNING: vmlinux.o(.data+0x1ad9dc): Section mismatch in reference from the variable s3c2416_cpufreq_driver to the function .init.text:s3c2416_cpufreq_driver_init()
WARNING: drivers/built-in.o(.text+0x35b5dc): Section mismatch in reference from the function s3c2410a_cpufreq_add() to the function .init.text:s3c_cpufreq_register()

This removes the __init markings.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On Dell Latitude C600 laptop with Pentium 3 850MHz processor, the
speedstep-smi driver sometimes loads and sometimes doesn't load with
"change to state X failed" message.

The hardware sometimes refuses to change frequency and in this case, we
need to retry later. I found out that we need to enable interrupts while
waiting. When we enable interrupts, the hardware blockage that prevents
frequency transition resolves and the transition is possible. With
disabled interrupts, the blockage doesn't resolve (no matter how long do
we wait). The exact reasons for this hardware behavior are unknown.

This patch enables interrupts in the function speedstep_set_state that can
be called with disabled interrupts. However, this function is called with
disabled interrupts only from speedstep_get_freqs, so it shouldn't cause
any problem.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com
Cc: All applicable <stable@vger.kernel.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Allow users the option to disable the driver for any hardware
which does not support HWP.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The cpufreq_cooling_unregister() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
[ rjw: Subject ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

To make code more readable and less error prone, lets create a helper macro for
iterating over all available governors.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

To make code more readable and less error prone, lets create a helper macro for
iterating over all active policies.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When cpufreq is disabled, the per-cpu variable would have been set to
NULL. Remove this unnecessary check.

[ Changelog from Saravana Kannan. ]
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In __cpufreq_remove_dev_finish(), per-cpu 'cpufreq_cpu_data' needs
to be cleared before calling kobject_put(&policy->kobj) and under
cpufreq_driver_lock. Otherwise, if someone else calls cpufreq_cpu_get()
in parallel with it, they can obtain a non-NULL policy from that after
kobject_put(&policy->kobj) was executed.

Consider this case:

Thread A				Thread B
cpufreq_cpu_get()
  acquire cpufreq_driver_lock
  read-per-cpu cpufreq_cpu_data
					kobject_put(&policy->kobj);
  kobject_get(&policy->kobj);
					...
					per_cpu(&cpufreq_cpu_data, cpu) = NULL

And this will result in a warning like this one:

 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 4 at include/linux/kref.h:47
 kobject_get+0x41/0x50()
 Modules linked in: acpi_cpufreq(+) nfsd auth_rpcgss nfs_acl
 lockd grace sunrpc xfs libcrc32c sd_mod ixgbe igb mdio ahci hwmon
 ...
 Call Trace:
  [<ffffffff81661b14>] dump_stack+0x46/0x58
  [<ffffffff81072b61>] warn_slowpath_common+0x81/0xa0
  [<ffffffff81072c7a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff812e16d1>] kobject_get+0x41/0x50
  [<ffffffff815262a5>] cpufreq_cpu_get+0x75/0xc0
  [<ffffffff81527c3e>] cpufreq_update_policy+0x2e/0x1f0
  [<ffffffff810b8cb2>] ? up+0x32/0x50
  [<ffffffff81381aa9>] ? acpi_ns_get_node+0xcb/0xf2
  [<ffffffff81381efd>] ? acpi_evaluate_object+0x22c/0x252
  [<ffffffff813824f6>] ? acpi_get_handle+0x95/0xc0
  [<ffffffff81360967>] ? acpi_has_method+0x25/0x40
  [<ffffffff81391e08>] acpi_processor_ppc_has_changed+0x77/0x82
  [<ffffffff81089566>] ? move_linked_works+0x66/0x90
  [<ffffffff8138e8ed>] acpi_processor_notify+0x58/0xe7
  [<ffffffff8137410c>] acpi_ev_notify_dispatch+0x44/0x5c
  [<ffffffff8135f293>] acpi_os_execute_deferred+0x15/0x22
  [<ffffffff8108c910>] process_one_work+0x160/0x410
  [<ffffffff8108d05b>] worker_thread+0x11b/0x520
  [<ffffffff8108cf40>] ? rescuer_thread+0x380/0x380
  [<ffffffff81092421>] kthread+0xe1/0x100
  [<ffffffff81092340>] ? kthread_create_on_node+0x1b0/0x1b0
  [<ffffffff81669ebc>] ret_from_fork+0x7c/0xb0
  [<ffffffff81092340>] ? kthread_create_on_node+0x1b0/0x1b0
 ---[ end trace 89e66eb9795efdf7 ]---

The actual code flow is as follows:

 Thread A: Workqueue: kacpi_notify

 acpi_processor_notify()
   acpi_processor_ppc_has_changed()
         cpufreq_update_policy()
           cpufreq_cpu_get()
             kobject_get()

 Thread B: xenbus_thread()

 xenbus_thread()
   msg->u.watch.handle->callback()
     handle_vcpu_hotplug_event()
       vcpu_hotplug()
         cpu_down()
           __cpu_notify(CPU_POST_DEAD..)
             cpufreq_cpu_callback()
               __cpufreq_remove_dev_finish()
                 cpufreq_policy_put_kobj()
                   kobject_put()

cpufreq_cpu_get() gets the policy from per-cpu variable cpufreq_cpu_data
under cpufreq_driver_lock, and once it gets a valid policy it expects it
to not be freed until cpufreq_cpu_put() is called.

But the race happens when another thread puts the kobject first and updates
cpufreq_cpu_data before or later. And so the first thread gets a valid policy
structure and before it does kobject_get() on it, the second one has already
done kobject_put().

Fix this by setting cpufreq_cpu_data to NULL before putting the kobject and that
too under locks.
Reported-by: NEthan Zhao <ethan.zhao@oracle.com>
Reported-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The exynos cpufreq driver code recently gained a dependency on the
cooling code, which may be a loadable module. This breaks an ARM
allmodconfig build:

drivers/built-in.o: In function `exynos_cpufreq_probe':
:(.text+0x1748e8): undefined reference to `of_cpufreq_cooling_register'

To avoid this problem, change cpufreq Kconfig to allow the drivers
to be loadable modules as well and enforce a dependency on the
thermal module.

This change, in order to allow module builds on this cpufreq
driver, properly constructs the driver into a single module,
instead of several modules. The change also keeps the proper
platform dependency, and therefore, it wont load in platforms
that are not supposed to be loaded. The user will be able to
build the support for all platforms, or select which platforms
(s)he wants (as originally), except that now it can be a module,
instead.

Besides, it will still keep the driver only on those configs
that expect it to be on. And it won't compile/load on platforms
that it is not supposed to. It brings the config ARM_EXYNOS_CPU_FREQ_BOOST_SW
closer to this driver, so it looks better in the menuconfig.

We intentionally change ARM_EXYNOS5440_CPUFREQ to be tristate too, to
avoid future troubles.

Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-pm@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Fixes: e725d26c ("cpufreq: exynos: Use device tree to determine if cpufreq cooling should be registered")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>

If the user has requested an override of the min_perf_pct via
sysfs, then it should be restored whenever policy is updated,
such as on resume.  Take the max of whatever the user requested
and whatever the policy is.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When thermal or other subsystem requests to change the policy,
use that irrepective of whether cpufreq policy is PERFORMANCE or
not. Without this change, when thermal subsystem passive policy wants
to reduce performance, it still runs at 100%.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add a sysfs interface to display the total number of supported
pstates.  This value is independent of whether turbo has been
enabled or disabled.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch adds "turbo_pct" to the intel_pstate sysfs interface.
turbo_pct will display the percentage of the total supported
pstates that are in the turbo range.  This value is independent
of whether turbo has been disabled or not.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add SKL cpuid.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

With thermal subsystem rework it is necessary to tune current cpufreq code
to use cpu frequency change as a potential cooling device.

Now the cpu cooling device is registered only when proper nodes and properties
are available in device tree. Lack of them, however, will not prevent
cpufreq for normal operation.
Signed-off-by: NLukasz Majewski <l.majewski@samsung.com>
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>

There is no possibility of any race on updating last_index, trans_table or
total_trans as these are updated only by cpufreq_stat_notifier_trans() which
will be called sequentially.

The only place where locking is still relevant is: cpufreq_stats_update(), which
updates time_in_state and last_time. This can be called by two thread in
parallel, that may result in races.

The two threads being:
- sysfs read of time_in_state
- and frequency transition that calls cpufreq_stat_notifier_trans().

Remove locking from the first case mentioned above.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

We need to call cpufreq_stats_update() to update 'time_in_state' for the last
frequency. This is achieved by calling it from cpufreq_stat_notifier_trans(),
which is called after frequency transition.

But if we detect that the cpu's frequency haven't really changed and its a false
POSTCHANGE notification, we don't really need to update time_in_state.

It wouldn't cause any harm in calling cpufreq_stats_update() but we can avoid
calling it here and call it when the frequency really changes. The result will
be the same but more efficient.
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>

cpufreq_stats_update() updates time_in_state and nothing else. It should ideally
be updated only in two cases:
- User requested for the current value of time_in_state.
- We have switched states and so need to update time for the last state.

Currently, we are also doing this while user asks for the transition table of
frequencies. It wouldn't do any harm, but no good as well. Its useless here.

Remove 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>