Conservative governor changes the CPU frequency in steps.
That means that if a CPU runs at max frequency, it will need several
sampling periods to return to min frequency when the workload
is finished.

If the update function that calculates the load and target frequency
is deferred, the governor might need even more time to decrease the
frequency.

This may have impact to power consumption and after all conservative
should decrease the frequency if there is no workload at every sampling
rate.

To resolve the above issue calculate the number of sampling periods
that the update is deferred. Considering that for each sampling period
conservative should drop the frequency by a freq_step because the
CPU was idle apply the proper subtraction to requested frequency.

Below, the kernel trace with and without this patch. First an
intensive workload is applied on a specific CPU. Then the workload
is removed and the CPU goes to idle.

WITHOUT

     <idle>-0     [007] dN..   620.329153: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   620.350857: cpu_frequency: state=1700000 cpu_id=7
kworker/7:2-556   [007] ....   620.370856: cpu_frequency: state=1900000 cpu_id=7
kworker/7:2-556   [007] ....   620.390854: cpu_frequency: state=2100000 cpu_id=7
kworker/7:2-556   [007] ....   620.411853: cpu_frequency: state=2200000 cpu_id=7
kworker/7:2-556   [007] ....   620.432854: cpu_frequency: state=2400000 cpu_id=7
kworker/7:2-556   [007] ....   620.453854: cpu_frequency: state=2600000 cpu_id=7
kworker/7:2-556   [007] ....   620.494856: cpu_frequency: state=2900000 cpu_id=7
kworker/7:2-556   [007] ....   620.515856: cpu_frequency: state=3100000 cpu_id=7
kworker/7:2-556   [007] ....   620.536858: cpu_frequency: state=3300000 cpu_id=7
kworker/7:2-556   [007] ....   620.557857: cpu_frequency: state=3401000 cpu_id=7
     <idle>-0     [007] d...   669.591363: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   669.591939: cpu_idle: state=4294967295 cpu_id=7
     <idle>-0     [007] d...   669.591980: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] dN..   669.591989: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   670.201224: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   670.221975: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   670.222016: cpu_frequency: state=3300000 cpu_id=7
     <idle>-0     [007] d...   670.222026: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   670.234964: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   670.801251: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   671.236046: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   671.236073: cpu_frequency: state=3100000 cpu_id=7
     <idle>-0     [007] d...   671.236112: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   671.393437: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   671.401277: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   671.404083: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   671.404111: cpu_frequency: state=2900000 cpu_id=7
     <idle>-0     [007] d...   671.404125: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   671.404974: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   671.501180: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   671.995414: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   671.995459: cpu_frequency: state=2800000 cpu_id=7
     <idle>-0     [007] d...   671.995469: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   671.996287: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   672.001305: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.078374: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   672.078410: cpu_frequency: state=2600000 cpu_id=7
     <idle>-0     [007] d...   672.078419: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.158020: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   672.158040: cpu_frequency: state=2400000 cpu_id=7
     <idle>-0     [007] d...   672.158044: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.160038: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   672.234557: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.237121: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   672.237174: cpu_frequency: state=2100000 cpu_id=7
     <idle>-0     [007] d...   672.237186: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.237778: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   672.267902: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.269860: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   672.269906: cpu_frequency: state=1900000 cpu_id=7
     <idle>-0     [007] d...   672.269914: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.271902: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...   672.751342: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...   672.823056: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-556   [007] ....   672.823095: cpu_frequency: state=1600000 cpu_id=7

WITH

     <idle>-0     [007] dN..  4380.928009: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-399   [007] ....  4380.949767: cpu_frequency: state=2000000 cpu_id=7
kworker/7:2-399   [007] ....  4380.969765: cpu_frequency: state=2200000 cpu_id=7
kworker/7:2-399   [007] ....  4381.009766: cpu_frequency: state=2500000 cpu_id=7
kworker/7:2-399   [007] ....  4381.029767: cpu_frequency: state=2600000 cpu_id=7
kworker/7:2-399   [007] ....  4381.049769: cpu_frequency: state=2800000 cpu_id=7
kworker/7:2-399   [007] ....  4381.069769: cpu_frequency: state=3000000 cpu_id=7
kworker/7:2-399   [007] ....  4381.089771: cpu_frequency: state=3100000 cpu_id=7
kworker/7:2-399   [007] ....  4381.109772: cpu_frequency: state=3400000 cpu_id=7
kworker/7:2-399   [007] ....  4381.129773: cpu_frequency: state=3401000 cpu_id=7
     <idle>-0     [007] d...  4428.226159: cpu_idle: state=1 cpu_id=7
     <idle>-0     [007] d...  4428.226176: cpu_idle: state=4294967295 cpu_id=7
     <idle>-0     [007] d...  4428.226181: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...  4428.227177: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...  4428.551640: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...  4428.649239: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-399   [007] ....  4428.649268: cpu_frequency: state=2800000 cpu_id=7
     <idle>-0     [007] d...  4428.649278: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...  4428.689856: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...  4428.799542: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...  4428.801683: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-399   [007] ....  4428.801748: cpu_frequency: state=1700000 cpu_id=7
     <idle>-0     [007] d...  4428.801761: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...  4428.806545: cpu_idle: state=4294967295 cpu_id=7
...
     <idle>-0     [007] d...  4429.051880: cpu_idle: state=4 cpu_id=7
     <idle>-0     [007] d...  4429.086240: cpu_idle: state=4294967295 cpu_id=7
kworker/7:2-399   [007] ....  4429.086293: cpu_frequency: state=1600000 cpu_id=7

Without the patch the CPU dropped to min frequency after 3.2s
With the patch applied the CPU dropped to min frequency after 0.86s
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

What's returned from this function is the delta by which the frequency
must be increased or decreased and not the final frequency that should
be selected.

Name it properly to match its purpose. Also update the variables used to
store that value.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

lpstate_idx remains uninitialized in the case when elapsed_time
is greater than MAX_RAMP_DOWN_TIME.  At the end of rampdown the
global pstate should be equal to the local pstate.

Fixes: 20b15b76 (cpufreq: powernv: Use PMCR to verify global and localpstate)
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAkshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use get_target_pstate_use_cpu_load() to calculate target P-State for
devices, with the preferred power management profile in ACPI FADT
set to PM_MOBILE.

This may help in resolving some thermal issues caused by low sustained
cpu bound workloads. The current algorithm tend to over provision in this
case as it doesn't look at the CPU busyness.

Also included the fix from Arnd Bergmann <arnd@arndb.de> to solve compile
issue, when CONFIG_ACPI is not defined.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

For device-tree based pxa25x and pxa27x platforms, cpufreq-dt driver is
doing the job as well as pxa2xx-cpufreq, so add these platforms to the
compatibility list.

This won't work for legacy non device-tree platforms where
pxa2xx-cpufreq is still required.
Signed-off-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Allow CPUfreq statistics to be cleared by writing anything to
/sys/.../cpufreq/stats/reset.
Signed-off-by: NMarkus Mayer <mmayer@broadcom.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The earlier implementation of governors used background timers and so
functions, mutex, etc had 'timer' keyword in their names.

But that's not true anymore. Replace 'timer' with 'update', as those
functions, variables are based around updates to frequency.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

As fast_switch() may get called with interrupt disable mode, we cannot
hold a mutex to update the global_pstate_info. So currently, fast_switch()
does not update the global_pstate_info and it will end up with stale data
whenever pstate is updated through fast_switch().

As the gpstate_timer can fire after fast_switch() has updated the pstates,
the timer handler cannot rely on the cached values of local and global
pstate and needs to read it from the PMCR.

Only gpstate_timer_handler() is affected by the stale cached pstate data
beacause either fast_switch() or target_index() routines will be called
for a given govenor, but gpstate_timer can fire after the governor has
changed to schedutil.
Signed-off-by: NAkshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: NGautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Adding fast_switch which does light weight operation to set the desired
pstate. Both global and local pstates are set to the same desired pstate.
Signed-off-by: NAkshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: NGautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fixes the following sparse warning:

drivers/cpufreq/brcmstb-avs-cpufreq.c:982:18: warning:
 symbol 'brcm_avs_cpufreq_attr' was not declared. Should it be static?
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NMarkus Mayer <mmayer@broadcom.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The limits variable gets modified from intel_pstate sysfs and also gets
modified from cpufreq sysfs. So protect with a mutex to keep data
integrity, when they are getting modified from multiple threads.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In order to aid debugging, we add a debugfs interface to the driver
that allows direct interaction with the AVS co-processor.

The debugfs interface provides a means for reading all and writing some
of the mailbox registers directly from the shell prompt and enables a
user to execute the communications protocol between ARM CPU and AVS CPU
step-by-step.

This interface should be used for debugging purposes only.
Signed-off-by: NMarkus Mayer <mmayer@broadcom.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This driver supports voltage and frequency scaling on Broadcom STB SoCs
using AVS firmware with DFS and DVFS support.

Actual frequency or voltage scaling is done exclusively by the AVS
firmware. The driver merely provides a standard CPUfreq interface to
other kernel components and userland, and instructs the AVS firmware to
perform frequency or voltage changes on its behalf.
Signed-off-by: NMarkus Mayer <mmayer@broadcom.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add compatible strings for Pro5, PXs2, LD6b, LD11, LD20 SoCs to use
the generic cpufreq driver.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When policy->max and policy->min are same, in some cases they don't
result in the same frequency cap. The max_policy_pct is rounded up but
not min_perf_pct. So even when they are same, results in different
percentage or maximum and minimum.
Since minimum is a conservative value for power, a lower value without
rounding is better in most of the cases, unless user wants
policy->max = policy->min.
This change uses use the same policy percentage when policy->max and
policy->min are same.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Intel P-State offers two interface to set performance limits:
- Intel P-State sysfs
	/sys/devices/system/cpu/intel_pstate/max_perf_pct
	/sys/devices/system/cpu/intel_pstate/min_perf_pct
- cpufreq
	/sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
	/sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq

In the current implementation both of the above methods, change limits
to every CPU in the system. Moreover the limits placed using cpufreq
policy interface also presented in the Intel P-State sysfs via modified
max_perf_pct and min_per_pct during sysfs reads. This allows to check
percent of reduced/increased performance, irrespective of method used to
limit.

There are some new generations of processors, where it is possible to
have limits placed on individual CPU cores. Using cpufreq interface it
is possible to set limits on each CPU. But the current processing will
use last limits placed on all CPUs. So the per core limit feature of
CPUs can't be used.

This change brings in capability to set P-States limits for each CPU,
with some limitations. In this case what should be the read of
max_perf_pct and min_perf_pct? It can be most restrictive limits placed
on any CPU or max possible performance on any given CPU on which no
limits are placed. In either case someone will have issue.

So the consensus is, we can't have both sysfs controls present when user
wants to use limit per core limits.
- By default per-core-control feature is not enabled. So no one will
notice any difference.
- The way to enable is by kernel command line
intel_pstate=per_cpu_perf_limits
- When the per-core-controls are enabled there is no display of for both
read and write on
	/sys/devices/system/cpu/intel_pstate/max_perf_pct
	/sys/devices/system/cpu/intel_pstate/min_perf_pct
- User can change limits using
	/sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
	/sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq
	/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
- User can still observe turbo percent and number of P-States from
	/sys/devices/system/cpu/intel_pstate/turbo_pct
	/sys/devices/system/cpu/intel_pstate/num_pstates
- User can read write system wide turbo status
	/sys/devices/system/cpu/no_turbo

While changing this BUG_ON is changed to WARN_ON, as they are not fatal
errors for the system.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

After switching the core module clocks controlling the Integrator
clock frequencies to the common clock framework, defining the
operating points in the device tree, and activating the generic
DT-based CPUfreq driver, we can retire the old Integrator
cpufreq driver.
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This enables the generic DT and OPP-based cpufreq driver on the
ARM Integrator/AP and Integrator/CP.
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The only times at which intel_pstate checks the policy set for
a given CPU is the initialization of that CPU and updates of its
policy settings from cpufreq when intel_pstate_set_policy() is
invoked.

That is insufficient, however, because intel_pstate uses the same
P-state selection function for all CPUs regardless of the policy
setting for each of them and the P-state limits are shared between
them.  Thus if the policy is set to "performance" for a particular
CPU, it may not behave as expected if the cpufreq settings are
changed subsequently for another CPU.

That can be easily demonstrated by writing "performance" to
scaling_governor for all CPUs and then switching it to "powersave"
for one of them in which case all of the CPUs will behave as though
their scaling_governor were all "powersave" (even though the policy
still appears to be "performance" for the remaining CPUs).

Fix this problem by modifying intel_pstate_adjust_busy_pstate() to
always set the P-state to the maximum allowed by the current limits
for all CPUs whose policy is set to "performance".

Note that it still is recommended to always change the policy setting
in the same way for all CPUs even with this fix applied to avoid
confusion.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

After commit a4675fbc (cpufreq: intel_pstate: Replace timers with
utilization update callbacks) the cpufreq governor callbacks may not
be invoked on NOHZ_FULL CPUs and, in particular, switching to the
"performance" policy via sysfs may not have any effect on them.  That
is a problem, because it usually is desirable to squeeze the last
bit of performance out of those CPUs, so work around it by setting
the maximum P-state (within the limits) in intel_pstate_set_policy()
upfront when the policy is CPUFREQ_POLICY_PERFORMANCE.

Fixes: a4675fbc (cpufreq: intel_pstate: Replace timers with utilization update callbacks)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

When target state is calculated using get_target_pstate_use_cpu_load(),
PID controller is not used, hence it has no effect on performance.
So don't present debugfs entries to tune PID controller.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The "IOwait boosting" mechanism is only used by the
get_target_pstate_use_cpu_load() governor function and the
boost_iowait flag in pid_params is always set when that function
is in use (and it is never set otherwise).  This means that the
boost_iowait flag is in fact redundant and may be dropped.

For this reason, replace the boost_iowait flag check in
intel_pstate_update_util() with an equivalent check against
pstate_funcs.get_target_pstate and drop that flag.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

MODULE_DEVICE_TABLE is added so that CPPC cpufreq module can be
automatically loaded when we have a acpi processor device with
"ACPI0007" hid.
Signed-off-by: NPrashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The desired_perf is an abstract performance number. Its value should
be in the range of [lowest perf, highest perf] of CPPC.
The correct calculation is
  desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz

And cppc_cpufreq_set_target() returns if desired_perf is exactly
the same with the old perf.
Signed-off-by: NHoan Tran <hotran@apm.com>
Reviewed-by: NPrashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit d352cf47 (cpufreq: conservative: Do not use transition
notifications) overlooked the case when the "frequency step" used
by the conservative governor is small relative to the distances
between the available frequencies and broke the algorithm by
using policy->cur instead of the previously requested frequency
when computing the next one.

As a result, the governor may not be able to go outside of a narrow
range between two consecutive available frequencies.

Fix the problem by making the governor save the previously requested
frequency and select the next one relative that value (unless it is
out of range, in which case policy->cur will be used instead).

Fixes: d352cf47 (cpufreq: conservative: Do not use transition notifications)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=177171Reported-and-tested-by: NAleksey Rybalkin <aleksey@rybalkin.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Cc: 4.8+ <stable@vger.kernel.org> # 4.8+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

It looks like the name of struct pstate_adjust_policy was updated
without updating its kerneldoc comment accordingly, so fix that
mistake.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The PID algorithm used by the intel_pstate driver tends to drive
performance to the minimum for workloads with utilization below the
setpoint, which is undesirable, so replace it with a modified
"proportional" algorithm on Atom.

The new algorithm will set the new P-state to be 1.25 times the
available maximum times the (frequency-invariant) utilization during
the previous sampling period except when the target P-state computed
this way is lower than the average P-state during the previous
sampling period.  In the latter case, it will increase the target by
50% of the difference between it and the average P-state to prevent
performance from dropping down too fast in some cases.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

Make the comment explaining the meaning of the perf_scaled variable
in get_target_pstate_use_performance() more straightforward.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This is a requirement that MSR MSR_PM_ENABLE must be set to 0x01 before
reading MSR_HWP_CAPABILITIES on a given CPU. If cpufreq init() is
scheduled on a CPU which is not same as policy->cpu or migrates to a
different CPU before calling msr read for MSR_HWP_CAPABILITIES, it
is possible that MSR_PM_ENABLE was not to set to 0x01 on that CPU.
This will cause GP fault. So like other places in this path
rdmsrl_on_cpu should be used instead of rdmsrl.

Moreover the scope of MSR_HWP_CAPABILITIES is on per thread basis, so it
should be read from the same CPU, for which MSR MSR_HWP_REQUEST is
getting set.

dmesg dump or warning:

[   22.014488] WARNING: CPU: 139 PID: 1 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x68/0x70
[   22.014492] unchecked MSR access error: RDMSR from 0x771
[   22.014493] Modules linked in:
[   22.014507] CPU: 139 PID: 1 Comm: swapper/0 Not tainted 4.7.5+ #1
...
...
[   22.014516] Call Trace:
[   22.014542]  [<ffffffff813d7dd1>] dump_stack+0x63/0x82
[   22.014558]  [<ffffffff8107bc8b>] __warn+0xcb/0xf0
[   22.014561]  [<ffffffff8107bcff>] warn_slowpath_fmt+0x4f/0x60
[   22.014563]  [<ffffffff810676f8>] ex_handler_rdmsr_unsafe+0x68/0x70
[   22.014564]  [<ffffffff810677d9>] fixup_exception+0x39/0x50
[   22.014604]  [<ffffffff8102e400>] do_general_protection+0x80/0x150
[   22.014610]  [<ffffffff817f9ec8>] general_protection+0x28/0x30
[   22.014635]  [<ffffffff81687940>] ? get_target_pstate_use_performance+0xb0/0xb0
[   22.014642]  [<ffffffff810600c7>] ? native_read_msr+0x7/0x40
[   22.014657]  [<ffffffff81688123>] intel_pstate_hwp_set+0x23/0x130
[   22.014660]  [<ffffffff81688406>] intel_pstate_set_policy+0x1b6/0x340
[   22.014662]  [<ffffffff816829bb>] cpufreq_set_policy+0xeb/0x2c0
[   22.014664]  [<ffffffff81682f39>] cpufreq_init_policy+0x79/0xe0
[   22.014666]  [<ffffffff81682cb0>] ? cpufreq_update_policy+0x120/0x120
[   22.014669]  [<ffffffff816833a6>] cpufreq_online+0x406/0x820
[   22.014671]  [<ffffffff8168381f>] cpufreq_add_dev+0x5f/0x90
[   22.014717]  [<ffffffff81530ac8>] subsys_interface_register+0xb8/0x100
[   22.014719]  [<ffffffff816821bc>] cpufreq_register_driver+0x14c/0x210
[   22.014749]  [<ffffffff81fe1d90>] intel_pstate_init+0x39d/0x4d5
[   22.014751]  [<ffffffff81fe13f2>] ? cpufreq_gov_dbs_init+0x12/0x12

Cc: 4.3+ <stable@vger.kernel.org> # 4.3+
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Trival fix, dev_err message is missing a \n, so add it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Trival fix, dev_err messages are missing a \n, so add it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The function cpufreq_register_driver() returns zero on success and since
commit 27622b06 ("cpufreq: Convert to hotplug state machine")
erroneously a positive number. Due to the "if (x) assume_error" construct
all callers assumed an error and as a consequence the cpu freq kworker
crashes with a NULL pointer dereference.

Reset the return value back to zero in the success case.

Fixes: 27622b06 ("cpufreq: Convert to hotplug state machine")
Reported-by: NBorislav Petkov <bp@alien8.de>
Reported-and-tested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: peterz@infradead.org
Cc: rjw@rjwysocki.net
Link: http://lkml.kernel.org/r/20160920145628.lp2bmq72ip3oiash@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Install the callbacks via the state machine.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: N"Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.or
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-13-bigeasy@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch fixes overflow issue when calculating the desired_perf.

Fixes: ad38677d (cpufreq: CPPC: Force reporting values in KHz to fix user space interface)
Signed-off-by: NHoan Tran <hotran@apm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Now that the cpufreq-dt-platdev is used to create the cpufreq-dt platform
device for all OMAP platforms and the platform code that did it
before has been removed, add ti,am33xx and ti,dra7xx to the machine list
in cpufreq-dt-platdev which had relied on the removed platform code to do
this previously.

Fixes: 7694ca6e (cpufreq: omap: Use generic platdev driver)
Signed-off-by: NDave Gerlach <d-gerlach@ti.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Cc: 4.7+ <stable@vger.kernel.org> # 4.7+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add io_boost percent to current pstate_sample tracepoint.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Modify the P-state selection algorithm for Atom processors to use
the new SCHED_CPUFREQ_IOWAIT flag instead of the questionable
get_cpu_iowait_time_us() function.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When CPPC is being used by ACPI on arm64, user space tools such as
cpupower report CPU frequency values from sysfs that are incorrect.

What the driver was doing was reporting the values given by ACPI tables
in whatever scale was used to provide them.  However, the ACPI spec
defines the CPPC values as unitless abstract numbers.  Internal kernel
structures such as struct perf_cap, in contrast, expect these values
to be in KHz.  When these struct values get reported via sysfs, the
user space tools also assume they are in KHz, causing them to report
incorrect values (for example, reporting a CPU frequency of 1MHz when
it should be 1.8GHz).

The downside is that this approach has some assumptions:

   (1) It relies on SMBIOS3 being used, *and* that the Max Frequency
   value for a processor is set to a non-zero value.

   (2) It assumes that all processors run at the same speed, or that
   the CPPC values have all been scaled to reflect relative speed.
   This patch retrieves the largest CPU Max Frequency from a type 4 DMI
   record that it can find.  This may not be an issue, however, as a
   sampling of DMI data on x86 and arm64 indicates there is often only
   one such record regardless.  Since CPPC is relatively new, it is
   unclear if the ACPI ASL will always be written to reflect any sort
   of relative performance of processors of differing speeds.

   (3) It assumes that performance and frequency both scale linearly.

For arm64 servers, this may be sufficient, but it does rely on
firmware values being set correctly.  Hence, other approaches will
be considered in the future.

This has been tested on three arm64 servers, with and without DMI, with
and without CPPC support.
Signed-off-by: NAl Stone <ahs3@redhat.com>
Signed-off-by: NPrashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If a cpufreq driver is registered very early in the boot stage (e.g.
registered from postcore_initcall()), then cpufreq core may generate
kernel warnings for it.

In this case, the CPUs are brought online, then the cpufreq driver is
registered, and then the CPU topology devices are registered. However,
by the time cpufreq_add_dev() gets called, the cpu device isn't stored
in the per-cpu variable (cpu_sys_devices,) which is read by
get_cpu_device().

So the cpufreq core fails to get device for the CPU, for which
cpufreq_add_dev() was called in the first place and we will hit a
WARN_ON(!cpu_dev).

Even if we reuse the 'dev' parameter passed to cpufreq_add_dev() to
avoid that warning, there might be other CPUs online that share the
policy with the cpu for which cpufreq_add_dev() is called. Eventually
get_cpu_device() will return NULL for them as well, and we will hit the
same WARN_ON() again.

In order to fix these issues, change cpufreq core to create links to the
policy for a cpu only when cpufreq_add_dev() is called for that CPU.

Reuse the 'real_cpus' mask to track that as well.

Note that cpufreq_remove_dev() already handles removal of the links for
individual CPUs and cpufreq_add_dev() has aligned with that now.
Reported-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

For structure types defined in the same file or local header files, find
top-level static structure declarations that have the following
properties:
1. Never reassigned.
2. Address never taken
3. Not passed to a top-level macro call
4. No pointer or array-typed field passed to a function or stored in a
variable.
Declare structures having all of these properties as const.

Done using Coccinelle.
Based on a suggestion by Joe Perches <joe@perches.com>.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>