linux-toradex.git/drivers/cpufreq/powernow-k8.c, branch v3.15.2

cpufreq: use kzalloc() to allocate memory for cpufreq_frequency_table

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

Few drivers are using kmalloc() to allocate memory for frequency
tables and since we will have an additional field '.flags' in
'struct cpufreq_frequency_table', these might become unstable.
Better get these fixed by replacing kmalloc() by kzalloc() instead.

Along with that we also remove use of .driver_data from SPEAr driver
as it doesn't use it at all. Also, writing zero to .driver_data is not
required for powernow-k8 as it is already zero.

Reported-and-reviewed-by: Gautham R. Shenoy 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end}

2014-03-26T15:41:41+00:00

CPUFreq core has new infrastructure that would guarantee serialized calls to
target() or target_index() callbacks. These are called
cpufreq_freq_transition_begin() and cpufreq_freq_transition_end().

This patch converts existing drivers to use these new set of routines.

Reviewed-by: Srivatsa S. Bhat 
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: powernow-k8: Initialize per-cpu data-structures properly

2014-02-19T00:04:56+00:00

The powernow-k8 driver maintains a per-cpu data-structure called
powernow_data that is used to perform the frequency transitions.
It initializes this data structure only for the policy->cpu. So,
accesses to this data structure by other CPUs results in various
problems because they would have been uninitialized.

Specifically, if a cpu (!= policy->cpu) invokes the drivers' ->get()
function, it returns 0 as the KHz value, since its per-cpu memory
doesn't point to anything valid. This causes problems during
suspend/resume since cpufreq_update_policy() tries to enforce this
(0 KHz) as the current frequency of the CPU, and this madness gets
propagated to adjust_jiffies() as well. Eventually, lots of things
start breaking down, including the r8169 ethernet card, in one
particularly interesting case reported by Pierre Ossman.

Fix this by initializing the per-cpu data-structures of all the CPUs
in the policy appropriately.

References: https://bugzilla.kernel.org/show_bug.cgi?id=70311
Reported-by: Pierre Ossman 
Signed-off-by: Srivatsa S. Bhat 
Cc: All applicable 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: send new set of notification for transition failures

2014-01-06T00:43:44+00:00

In the current code, if we fail during a frequency transition, we
simply send the POSTCHANGE notification with the old frequency. This
isn't enough.

One of the core users of these notifications is the code responsible
for keeping loops_per_jiffy aligned with frequency changes. And mostly
it is written as:

	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
	    (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
		update-loops-per-jiffy...
	}

So, suppose we are changing to a higher frequency and failed during
transition, then following will happen:
- CPUFREQ_PRECHANGE notification with freq-new > freq-old
- CPUFREQ_POSTCHANGE notification with freq-new == freq-old

The first one will update loops_per_jiffy and second one will do
nothing. Even if we send the 2nd notification by exchanging values of
freq-new and old, some users of these notifications might get
unstable.

This can be fixed by simply calling cpufreq_notify_post_transition()
with error code and this routine will take care of sending
notifications in the correct order.

Signed-off-by: Viresh Kumar 
[rjw: Folded 3 patches into one, rebased unicore2 changes]
Signed-off-by: Rafael J. Wysocki

cpufreq: distinguish drivers that do asynchronous notifications

2013-10-30T23:11:08+00:00

There are few special cases like exynos5440 which doesn't send POSTCHANGE
notification from their ->target() routine and call some kind of bottom halves
for doing this work, work/tasklet/etc.. From which they finally send POSTCHANGE
notification.

Its better if we distinguish them from other cpufreq drivers in some way so that
core can handle them specially. So this patch introduces another flag:
CPUFREQ_ASYNC_NOTIFICATION, which will be set by such drivers.

This also changes exynos5440-cpufreq.c and powernow-k8 in order to set this
flag.

Acked-by: Amit Daniel Kachhap 
Acked-by: Kukjin Kim 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Implement light weight ->target_index() routine

2013-10-25T20:42:24+00:00

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: Hans-Christian Egtvedt 
Acked-by: Jesper Nilsson 
Acked-by: Linus Walleij 
Acked-by: Russell King 
Acked-by: David S. Miller 
Tested-by: Andrew Lunn 
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: powernow: don't initialize part of policy set by core

2013-10-15T22:50:31+00:00

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().

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

cpufreq: powernow: Use generic cpufreq routines

2013-10-15T22:50:26+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 uses these generic routines in the powernow driver.

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

cpufreq: powernow: use cpufreq_table_validate_and_show()

2013-09-30T18:18:43+00:00

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

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