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PM / OPP: Move cpufreq specific OPP functions out of generic OPP library

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CPUFreq specific helper functions for OPP (Operating Performance Points)
now use generic OPP functions that allow CPUFreq to be be moved back
into CPUFreq framework. This allows for independent modifications
or future enhancements as needed isolated to just CPUFreq framework
alone.

Here, we just move relevant code and documentation to make this part of
CPUFreq infrastructure.

Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Nishanth Menon
2014-05-05 08:33:50 -05:00
committed by Rafael J. Wysocki
parent 0f5c890e9b
commit a0dd7b7965
7 changed files with 167 additions and 147 deletions
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40
Documentation/power/opp.txt
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@@ -10,8 +10,7 @@ Contents
3. OPP Search Functions
4. OPP Availability Control Functions
5. OPP Data Retrieval Functions
6. Cpufreq Table Generation
7. Data Structures
6. Data Structures
1. Introduction
===============
@@ -72,7 +71,6 @@ operations until that OPP could be re-enabled if possible.
OPP library facilitates this concept in it's implementation. The following
operational functions operate only on available opps:
opp_find_freq_{ceil, floor}, dev_pm_opp_get_voltage, dev_pm_opp_get_freq, dev_pm_opp_get_opp_count
and dev_pm_opp_init_cpufreq_table
dev_pm_opp_find_freq_exact is meant to be used to find the opp pointer which can then
be used for dev_pm_opp_enable/disable functions to make an opp available as required.
@@ -96,10 +94,9 @@ using RCU read locks. The opp_find_freq_{exact,ceil,floor},
opp_get_{voltage, freq, opp_count} fall into this category.
opp_{add,enable,disable} are updaters which use mutex and implement it's own
RCU locking mechanisms. dev_pm_opp_init_cpufreq_table acts as an updater and uses
mutex to implment RCU updater strategy. These functions should *NOT* be called
under RCU locks and other contexts that prevent blocking functions in RCU or
mutex operations from working.
RCU locking mechanisms. These functions should *NOT* be called under RCU locks
and other contexts that prevent blocking functions in RCU or mutex operations
from working.
2. Initial OPP List Registration
================================
@@ -311,34 +308,7 @@ dev_pm_opp_get_opp_count - Retrieve the number of available opps for a device
/* Do other things */
}
6. Cpufreq Table Generation
===========================
dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
cpufreq_frequency_table_cpuinfo which is provided with the list of
frequencies that are available for operation. This function provides
a ready to use conversion routine to translate the OPP layer's internal
information about the available frequencies into a format readily
providable to cpufreq.
WARNING: Do not use this function in interrupt context.
Example:
soc_pm_init()
{
/* Do things */
r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
if (!r)
cpufreq_frequency_table_cpuinfo(policy, freq_table);
/* Do other things */
}
NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in
addition to CONFIG_PM as power management feature is required to
dynamically scale voltage and frequency in a system.
dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table
7. Data Structures
6. Data Structures
==================
Typically an SoC contains multiple voltage domains which are variable. Each
domain is represented by a device pointer. The relationship to OPP can be