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>

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>

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>

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>

Add a few comments in the code which calculates busyness to
clarify parts of the algorithm.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

To force loading on Oracle Sun X86 servers, provide one kernel command line
parameter

  intel_pstate = force

For those who are aware of the risk of no power capping capabily working
and try to get better performance with this driver.
Signed-off-by: NEthan Zhao <ethan.zhao@oracle.com>
Tested-by: NAlexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: NLinda Knippers <linda.knippers@hp.com>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Oracle Sun X86 servers have dynamic power capping capability that works via
ACPI _PPC method etc, so skip loading this driver if Sun server has ACPI _PPC
enabled.
Signed-off-by: NEthan Zhao <ethan.zhao@oracle.com>
Tested-by: NLinda Knippers <linda.knippers@hp.com>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add BDW-H to the list of supported processors.
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add support of Hardware Managed Performance States (HWP) described in Volume 3
section 14.4 of the SDM.

With HWP enbaled intel_pstate will no longer be responsible for selecting P
states for the processor. intel_pstate will continue to register to
the cpufreq core as the scaling driver for CPUs implementing
HWP. In HWP mode intel_pstate provides three functions reporting
frequency to the cpufreq core, support for the set_policy() interface
from the core and maintaining the intel_pstate sysfs interface in
/sys/devices/system/cpu/intel_pstate.  User preferences expressed via
the set_policy() interface or the sysfs interface are forwared to the
CPU via the HWP MSR interface.
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Using a VID value that is not high enough for the requested P state can
cause machine checks. Add a ceiling function to ensure calulated VIDs
with fractional values are set to the next highest integer VID value.

The algorythm for calculating the non-trubo VID from the BIOS writers
guide is:
 vid_ratio = (vid_max - vid_min) / (max_pstate - min_pstate)
 vid = ceiling(vid_min + (req_pstate - min_pstate) * vid_ratio)

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

BYT has a different conversion from P state to frequency than the core
processors.  This causes the min/max and current frequency to be
misreported on some BYT SKUs. Tested on BYT N2820, Ivybridge and
Haswell processors.

Link: https://bugzilla.yoctoproject.org/show_bug.cgi?id=6663
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The user may have custom settings don't destroy them during suspend.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=80651Reported-by: NTobias Jakobi <liquid.acid@gmx.net>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Some BIOSes modify the state of MSR_IA32_MISC_ENABLE_TURBO_DISABLE
based on the current power source for the system battery AC vs
battery. Reflect the correct current state and ability to modify the
no_turbo sysfs file based on current state of
MSR_IA32_MISC_ENABLE_TURBO_DISABLE.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=83151
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NGabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Code which changes policy to powersave changes also max_policy_pct based on
max_freq. Code which change max_perf_pct has upper limit base on value
max_policy_pct. When policy is changing from powersave back to performance
then max_policy_pct is not changed. Which means that changing max_perf_pct is
not possible to high values if max_freq was too low in powersave policy.

Test case:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
800000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
3300000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
performance
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct
100

$ echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
$ echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
$ echo 20 > /sys/devices/system/cpu/intel_pstate/max_perf_pct

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
powersave
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
800000
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct
20

$ echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
$ echo 3300000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
$ echo 100 > /sys/devices/system/cpu/intel_pstate/max_perf_pct

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
performance
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
3300000
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct
24

And now intel_pstate driver allows to set maximal value for max_perf_pct based
on max_policy_pct which is 24 for previous powersave max_freq 800000.

This patch will set default value for max_policy_pct when setting policy to
performance so it will allow to set also max value for max_perf_pct.
Signed-off-by: NPali Rohár <pali.rohar@gmail.com>
Cc: All applicable <stable@vger.kernel.org>
Acked-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

It should have been removed with commit d1b68485
("cpufreq / intel_pstate: Optimize intel_pstate_set_policy")
Signed-off-by: NGabriele Mazzotta <gabriele.mzt@gmail.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This is pretty much the same as Intel Baytrail, only the CPU ID is
different. Add the new ID to the supported CPU list.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On larger systems intel_pstate currently spams the boot up
log with its "Intel pstate controlling ..." message for each CPU.
It's the only subsystem that prints a message for each
CPU.

Turn the message into a pr_debug.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The specific rounding adds conditionally only 1/256 to fractional
part of core_pct.

We can safely remove it without any noticeable impact in
calculations.

Use div64_u64 instead of div_u64 to avoid possible overflow of
sample->mperf as divisor
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Simplify the code by removing the inline functions pstate_increase and
pstate_decrease and use directly the intel_pstate_set_pstate.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Acked-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently we shift right aperf and mperf variables by FRAC_BITS
to prevent overflow when we convert them to fix point numbers
(shift left by FRAC_BITS).

But this is not necessary, because we actually use delta aperf and mperf
which are much less than APERF and MPERF values.

So, use the unmodified APERF and MPERF values in calculation.
This also adds 8 bits in precision, although the gain is insignificant.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

According to Intel 64 and IA-32 Architectures SDM, Volume 3,
Chapter 14.2, "Software needs to exercise care to avoid delays
between the two RDMSRs (for example interrupts)".

So, disable interrupts during reading MSRs IA32_APERF and IA32_MPERF.
This should increase the accuracy of the calculations.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Suppress checkpatch.pl --strict warnings:
CHECK: Alignment should match open parenthesis
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Remove the unnecessary intermediate assignment and use directly the
pid_params.sample_rate_ms variable.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Remove unnecessary parentheses.
Also, add parentheses in one case for better readability.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

We can fit these lines in a single one, under the 80 characters
limit.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Also, remove unnecessary blank lines.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

div_s64() accepts the divisor parameter as s32. Helper div_fp()
also accepts divisor as int32_t.

So, remove the unnecessary int64_t type casting.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Since we never remove sysfs entry and debugfs files, we can make
the intel_pstate_kobject and debugfs_parent locals.

Also, annotate with __init intel_pstate_sysfs_expose_params()
and intel_pstate_debug_expose_params() in order to be freed
after bootstrap.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Ensure that cpu->cpu is set before writing MSR_IA32_PERF_CTL during CPU
initialization. Otherwise only cpu0 has its P-state set and all other
cores are left with their values unchanged.

In most cases, this is not too serious because the P-states will be set
correctly when the timer function is run.  But when the default governor
is set to performance, the per-CPU current_pstate stays the same forever
and no attempts are made to write the MSRs again.
Signed-off-by: NVincent Minet <vincent@vincent-minet.net>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If turbo is disabled in the BIOS bit 38 should be set in
MSR_IA32_MISC_ENABLE register per section 14.3.2.1 of the SDM Vol 3
document 325384-050US Feb 2014.  If this bit is set do *not* attempt
to disable trubo via the MSR_IA32_PERF_CTL register.  On some systems
trying to disable turbo via MSR_IA32_PERF_CTL will cause subsequent
writes to MSR_IA32_PERF_CTL not take affect, in fact reading
MSR_IA32_PERF_CTL will not show the IDA/Turbo DISENGAGE bit(32) as
set. A write of bit 32 to zero returns to normal operation.

Also deal with the case where the processor does not support
turbo and the BIOS does not report the fact in MSR_IA32_MISC_ENABLE
but does report the max and turbo P states as the same value.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=64251
Cc: 3.13+ <stable@vger.kernel.org>  # 3.13+
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit 21855ff5 (intel_pstate: Set turbo VID for BayTrail) introduced
setting the turbo VID which is required to prevent a machine check on
some Baytrail SKUs under heavy graphics based workloads.  The
docmumentation update that brought the requirement to light also
changed the bit mask used for enumerating P state and VID values from
0x7f to 0x3f.

This change returns the mask value to 0x7f.

Tested with the Intel NUC DN2820FYK,
BIOS version FYBYT10H.86A.0034.2014.0513.1413 with v3.16-rc1 and
v3.14.8 kernel versions.

Fixes: 21855ff5 (intel_pstate: Set turbo VID for BayTrail)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77951Reported-and-tested-by: NRune Reterson <rune@megahurts.dk>
Reported-and-tested-by: NEric Eickmeyer <erich@ericheickmeyer.com>
Cc: 3.13+ <stable@vger.kernel.org>  # 3.13+
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There was a mistake in the actual rounding portion this previous patch:
f0fe3cd7 (intel_pstate: Correct rounding in busy calculation) such that
the rounding was asymetric and incorrect.

Severity: Not very serious, but can increase target pstate by one extra value.
For real world work flows the issue should self correct (but I have no proof).
It is the equivalent of different PID gains for positive and negative numbers.

Examples:
 -3.000000 used to round to -4, rounds to -3 with this patch.
 -3.503906 used to round to -5, rounds to -4 with this patch.

Fixes: f0fe3cd7 (intel_pstate: Correct rounding in busy calculation)
Signed-off-by: NDoug Smythies <dsmythies@telus.net>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

We check the CPU ID during driver init. There is no need
to do it again per logical CPU initialization.

So, remove the duplicate check.
Signed-off-by: NStratos Karafotis <stratosk@semaphore.gr>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>