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authorNishanth Menon <nm@ti.com>2014-05-05 09:33:50 -0400
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-05-06 18:39:03 -0400
commita0dd7b79657bd6644b914d16ce7f23468c44a7b4 (patch)
tree471993f62816ed76d5cb7f96b32659f5bed439a6 /Documentation
parent0f5c890e9b9754d9aa5bf6ae2fc00cae65780d23 (diff)
PM / OPP: Move cpufreq specific OPP functions out of generic OPP library
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/cpu-freq/core.txt29
-rw-r--r--Documentation/power/opp.txt40
2 files changed, 34 insertions, 35 deletions
diff --git a/Documentation/cpu-freq/core.txt b/Documentation/cpu-freq/core.txt
index 0060d76b445f..70933eadc308 100644
--- a/Documentation/cpu-freq/core.txt
+++ b/Documentation/cpu-freq/core.txt
@@ -20,6 +20,7 @@ Contents:
20--------- 20---------
211. CPUFreq core and interfaces 211. CPUFreq core and interfaces
222. CPUFreq notifiers 222. CPUFreq notifiers
233. CPUFreq Table Generation with Operating Performance Point (OPP)
23 24
241. General Information 251. General Information
25======================= 26=======================
@@ -92,3 +93,31 @@ values:
92cpu - number of the affected CPU 93cpu - number of the affected CPU
93old - old frequency 94old - old frequency
94new - new frequency 95new - new frequency
96
973. CPUFreq Table Generation with Operating Performance Point (OPP)
98==================================================================
99For details about OPP, see Documentation/power/opp.txt
100
101dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
102 cpufreq_frequency_table_cpuinfo which is provided with the list of
103 frequencies that are available for operation. This function provides
104 a ready to use conversion routine to translate the OPP layer's internal
105 information about the available frequencies into a format readily
106 providable to cpufreq.
107
108 WARNING: Do not use this function in interrupt context.
109
110 Example:
111 soc_pm_init()
112 {
113 /* Do things */
114 r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
115 if (!r)
116 cpufreq_frequency_table_cpuinfo(policy, freq_table);
117 /* Do other things */
118 }
119
120 NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in
121 addition to CONFIG_PM_OPP.
122
123dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table
diff --git a/Documentation/power/opp.txt b/Documentation/power/opp.txt
index b8a907dc0169..a9adad828cdc 100644
--- a/Documentation/power/opp.txt
+++ b/Documentation/power/opp.txt
@@ -10,8 +10,7 @@ Contents
103. OPP Search Functions 103. OPP Search Functions
114. OPP Availability Control Functions 114. OPP Availability Control Functions
125. OPP Data Retrieval Functions 125. OPP Data Retrieval Functions
136. Cpufreq Table Generation 136. Data Structures
147. Data Structures
15 14
161. Introduction 151. Introduction
17=============== 16===============
@@ -72,7 +71,6 @@ operations until that OPP could be re-enabled if possible.
72OPP library facilitates this concept in it's implementation. The following 71OPP library facilitates this concept in it's implementation. The following
73operational functions operate only on available opps: 72operational functions operate only on available opps:
74opp_find_freq_{ceil, floor}, dev_pm_opp_get_voltage, dev_pm_opp_get_freq, dev_pm_opp_get_opp_count 73opp_find_freq_{ceil, floor}, dev_pm_opp_get_voltage, dev_pm_opp_get_freq, dev_pm_opp_get_opp_count
75and dev_pm_opp_init_cpufreq_table
76 74
77dev_pm_opp_find_freq_exact is meant to be used to find the opp pointer which can then 75dev_pm_opp_find_freq_exact is meant to be used to find the opp pointer which can then
78be used for dev_pm_opp_enable/disable functions to make an opp available as required. 76be 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},
96opp_get_{voltage, freq, opp_count} fall into this category. 94opp_get_{voltage, freq, opp_count} fall into this category.
97 95
98opp_{add,enable,disable} are updaters which use mutex and implement it's own 96opp_{add,enable,disable} are updaters which use mutex and implement it's own
99RCU locking mechanisms. dev_pm_opp_init_cpufreq_table acts as an updater and uses 97RCU locking mechanisms. These functions should *NOT* be called under RCU locks
100mutex to implment RCU updater strategy. These functions should *NOT* be called 98and other contexts that prevent blocking functions in RCU or mutex operations
101under RCU locks and other contexts that prevent blocking functions in RCU or 99from working.
102mutex operations from working.
103 100
1042. Initial OPP List Registration 1012. Initial OPP List Registration
105================================ 102================================
@@ -311,34 +308,7 @@ dev_pm_opp_get_opp_count - Retrieve the number of available opps for a device
311 /* Do other things */ 308 /* Do other things */
312 } 309 }
313 310
3146. Cpufreq Table Generation 3116. Data Structures
315===========================
316dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
317 cpufreq_frequency_table_cpuinfo which is provided with the list of
318 frequencies that are available for operation. This function provides
319 a ready to use conversion routine to translate the OPP layer's internal
320 information about the available frequencies into a format readily
321 providable to cpufreq.
322
323 WARNING: Do not use this function in interrupt context.
324
325 Example:
326 soc_pm_init()
327 {
328 /* Do things */
329 r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
330 if (!r)
331 cpufreq_frequency_table_cpuinfo(policy, freq_table);
332 /* Do other things */
333 }
334
335 NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in
336 addition to CONFIG_PM as power management feature is required to
337 dynamically scale voltage and frequency in a system.
338
339dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table
340
3417. Data Structures
342================== 312==================
343Typically an SoC contains multiple voltage domains which are variable. Each 313Typically an SoC contains multiple voltage domains which are variable. Each
344domain is represented by a device pointer. The relationship to OPP can be 314domain is represented by a device pointer. The relationship to OPP can be