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 frequency table.

On some systems we can't really say what frequency we're running at the moment
and so for these we shouldn't check if we are running at a frequency present in
frequency table. And so we really can't force this for all the cpufreq drivers.

Hence we are created another flag here: CPUFREQ_NEED_INITIAL_FREQ_CHECK that
will be marked by platforms which want to go for this check at boot time.

Initially this is done for all ARM platforms but others may follow if required.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Most of the drivers do following in their ->target_index() routines:

	struct cpufreq_freqs freqs;
	freqs.old = old freq...
	freqs.new = new freq...

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	/* Change rate here */

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

This is replicated over all cpufreq drivers today and there doesn't exists a
good enough reason why this shouldn't be moved to cpufreq core instead.

There are few special cases though, like exynos5440, which doesn't do everything
on the call to ->target_index() routine and call some kind of bottom halves for
doing this work, work/tasklet/etc..

They may continue doing notification from their own code as flag:
CPUFREQ_ASYNC_NOTIFICATION is already set for them.

All drivers are also modified in this patch to avoid breaking 'git bisect', as
double notification would happen otherwise.
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NRussell King <linux@arm.linux.org.uk>
Acked-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Tested-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently, the prototype of cpufreq_drivers target routines is:

int target(struct cpufreq_policy *policy, unsigned int target_freq,
		unsigned int relation);

And most of the drivers call cpufreq_frequency_table_target() to get a valid
index of their frequency table which is closest to the target_freq. And they
don't use target_freq and relation after that.

So, it makes sense to just do this work in cpufreq core before calling
cpufreq_frequency_table_target() and simply pass index instead. But this can be
done only with drivers which expose their frequency table with cpufreq core. For
others we need to stick with the old prototype of target() until those drivers
are converted to expose frequency tables.

This patch implements the new light weight prototype for target_index() routine.
It looks like this:

int target_index(struct cpufreq_policy *policy, unsigned int index);

CPUFreq core will call cpufreq_frequency_table_target() before calling this
routine and pass index to it. Because CPUFreq core now requires to call routines
present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time.

This also marks target() interface as deprecated. So, that new drivers avoid
using it. And Documentation is updated accordingly.

It also converts existing .target() to newly defined light weight
.target_index() routine for many driver.
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NRussell King <linux@arm.linux.org.uk>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rjw@rjwysocki.net>

Use generic cpufreq_generic_init() routine instead of replicating the same code
here.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.

Most recent of those changes is to call ->get() in the core after calling
->init().

Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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 uses these generic routines in the s3cx4xx driver.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Lets use cpufreq_table_validate_and_show() instead of calling
cpufreq_frequency_table_cpuinfo() and cpufreq_frequency_table_get_attr().

Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

We don't need to set .owner = THIS_MODULE any more in cpufreq drivers
as this field isn't used any more by the cpufreq core.

This patch removes it and updates all dependent drivers accordingly.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit 50701588 (cpufreq: rename index as driver_data in
cpufreq_frequency_table) renamed the index field to driver_data.

But it seems some uses in the s3c2416 driver were forgotten.

So convert the last index users to read driver_data.
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>

Correct spelling typo in printk within various drivers.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The "index" field of struct cpufreq_frequency_table was never an
index and isn't used at all by the cpufreq core.  It only is useful
for cpufreq drivers for their internal purposes.

Many people nowadays blindly set it in ascending order with the
assumption that the core will use it, which is a mistake.

Rename it to "driver_data" as that's what its purpose is. All of its
users are updated accordingly.

[rjw: Changelog]
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

policy->cpus contains all online cpus that have single shared clock line. And
their frequencies are always updated together.

Many SMP system's cpufreq drivers take care of this in individual drivers but
the best place for this code is in cpufreq core.

This patch modifies cpufreq_notify_transition() to notify frequency change for
all cpus in policy->cpus and hence updates all users of this API.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Correct spelling typo in cpufreq driver.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The S3C2416/S3C2450 SoCs support two sources for the armclk.

The first source is the so called armdiv which divides the msysclk down
to provide necessary cpu rates. In this mode the core voltage must be
always at 1.3V. The frequency from the armdiv is not allowed to be
lower than the hclk frequency.

In the second mode the armclk can be sourced directly from the hclk in
the so called "dynamic voltags scaling" (dvs) mode. Here the armdiv
isn't used at all. Also in this mode the core voltage may be lowered.
Existing hardware and tests with it suggest 1.0V as sufficient.

When changing the clock source to the armdiv from the hclk, the SoC
shows stability issues if the new frequency is higher than the current
hclk frequency. Hence the driver always forces the armdiv to the hclk
frequency before the source change and lets the cpufreq issue another
set_target call for higher frequencies.

To mark the hclk frequency as lower as the corresponding armdiv
frequency it is set 1MHz below the real frequency. This lets the cpufreq
framework change between 133MHz based on hclk and 133MHz based on armdiv
at will.
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Tested-by: NAndrey Gusakov <dron0gus@gmail.com>
Signed-off-by: NDave Jones <davej@redhat.com>