linux-stable.git/drivers/cpufreq/freq_table.c, branch linux-4.2.y

cpufreq: Allow freq_table to be obtained for offline CPUs

2015-07-09T23:43:27+00:00

Users of freq table may want to access it for any CPU from
policy->related_cpus mask. One such user is cpu-cooling layer. It gets a
list of 'clip_cpus' (equivalent to policy->related_cpus) during
registration and tries to get freq_table for the first CPU of this mask.

If the CPU, for which it tries to fetch freq_table, is offline,
cpufreq_frequency_get_table() fails. This happens because it relies on
cpufreq_cpu_get_raw() for its functioning which returns policy only for
online CPUs.

The fix is to access the policy data structure for the given CPU
directly (which also returns a valid policy for offline CPUs), but the
policy itself has to be active (meaning that at least one CPU using it
is online) for the frequency table to be returned.

Because we will be using 'cpufreq_cpu_data' now, which is internal to
the cpufreq core, move cpufreq_frequency_get_table() to cpufreq.c.

Reported-and-tested-by: Pi-Cheng Chen 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Introduce new relation for freq selection

2014-07-21T11:43:19+00:00

Introduce CPUFREQ_RELATION_C for frequency selection.
It selects the frequency with the minimum euclidean distance to target.
In case of equal distance between 2 frequencies, it will select the
greater frequency.

Signed-off-by: Stratos Karafotis 
Signed-off-by: Rafael J. Wysocki

cpufreq: Break out early when frequency equals target_freq

2014-05-20T12:02:09+00:00

Many drivers keep frequencies in frequency table in ascending
or descending order. When governor tries to change to policy->min
or policy->max respectively then the cpufreq_frequency_table_target
could return on first iteration. This will save some iteration cycles.

So, break out early when a frequency in cpufreq_frequency_table
equals to target one.

Testing this during kernel compilation using ondemand governor
with a frequency table in ascending order, the
cpufreq_frequency_table_target returned early on the first
iteration at about 30% of times called.

Signed-off-by: Stratos Karafotis 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Use cpufreq_for_each_* macros for frequency table iteration

2014-04-29T22:06:21+00:00

The cpufreq core now supports the cpufreq_for_each_entry and
cpufreq_for_each_valid_entry macros helpers for iteration over the
cpufreq_frequency_table, so use them.

It should have no functional changes.

Signed-off-by: Stratos Karafotis 
Acked-by: Lad, Prabhakar 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: create another field .flags in cpufreq_frequency_table

2014-04-07T12:43:50+00:00

Currently cpufreq frequency table has two fields: frequency and driver_data.
driver_data is only for drivers' internal use and cpufreq core shouldn't use
it at all. But with the introduction of BOOST frequencies, this assumption
was broken and we started using it as a flag instead.

There are two problems due to this:
- It is against the description of this field, as driver's data is used by
  the core now.
- if drivers fill it with -3 for any frequency, then those frequencies are
  never considered by cpufreq core as it is exactly same as value of
  CPUFREQ_BOOST_FREQ, i.e. ~2.

The best way to get this fixed is by creating another field flags which
will be used for such flags. This patch does that. Along with that various
drivers need modifications due to the change of struct cpufreq_frequency_table.

Reviewed-by: Gautham R Shenoy 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: don't print value of .driver_data from core

2014-04-07T12:43:49+00:00

CPUFreq core doesn't control value of .driver_data and this field is
completely driver specific. This can contain any value and not only
indexes. For most of the drivers, which aren't using this field, its
value is zero. So, printing this from core doesn't make any sense.
Don't print it.

Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: add 'freq_table' in struct cpufreq_policy

2014-03-12T00:06:00+00:00

freq table is not per CPU but per policy, so it makes more sense to
keep it within struct cpufreq_policy instead of a per-cpu variable.

This patch does it. Over that, there is no need to set policy->freq_table
to NULL in ->exit(), as policy structure is going to be freed soon.

Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Add boost frequency support in core

2014-01-17T01:00:44+00:00

This commit adds boost frequency support in cpufreq core (Hardware &
Software). Some SoCs (like Exynos4 - e.g. 4x12) allow setting frequency
above its normal operation limits. Such mode shall be only used for a
short time.

Overclocking (boost) support is essentially provided by platform
dependent cpufreq driver.

This commit unifies support for SW and HW (Intel) overclocking solutions
in the core cpufreq driver. Previously the "boost" sysfs attribute was
defined in the ACPI processor driver code. By default boost is disabled.
One global attribute is available at: /sys/devices/system/cpu/cpufreq/boost.

It only shows up when cpufreq driver supports overclocking.
Under the hood frequencies dedicated for boosting are marked with a
special flag (CPUFREQ_BOOST_FREQ) at driver's frequency table.
It is the user's concern to enable/disable overclocking with a proper call
to sysfs.

The cpufreq_boost_trigger_state() function is defined non static on purpose.
It is used later with thermal subsystem to provide automatic enable/disable
of the BOOST feature.

Signed-off-by: Lukasz Majewski 
Signed-off-by: Myungjoo Ham 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Make sure CPU is running on a freq from freq-table

2014-01-06T13:17:25+00:00

Sometimes boot loaders set CPU frequency to a value outside of frequency table
present with cpufreq core. In such cases CPU might be unstable if it has to run
on that frequency for long duration of time and so its better to set it to a
frequency which is specified in freq-table. This also makes cpufreq stats
inconsistent as cpufreq-stats would fail to register because current frequency
of CPU isn't found in freq-table.

Because we don't want this change to affect boot process badly, we go for the
next freq which is >= policy->cur ('cur' must be set by now, otherwise we will
end up setting freq to lowest of the table as 'cur' is initialized to zero).

In case current frequency doesn't match any frequency from freq-table, we throw
warnings to user, so that user can get this fixed in their bootloaders or
freq-tables.

Reported-by: Carlos Hernandez 
Reported-and-tested-by: Nishanth Menon 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: define generic .attr, .exit() and .verify() routines

2013-10-15T22:50:23+00:00

Most of the CPUFreq drivers do similar things in .exit() and .verify() routines
and .attr. So its better if we have generic routines for them which can be used
by cpufreq drivers then.

This patch introduces generic .attr, .exit() and .verify() cpufreq drivers.

Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki