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author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-06-03 23:13:20 +0200 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-06-03 23:13:20 +0200 |
commit | 057beb1de54d33ecfd3397ed219b1f4518e3b470 (patch) | |
tree | 7c67e9d8c88093a3d551111e56401826a964ffba /Documentation/power | |
parent | Merge branch 'pm-devfreq' (diff) | |
parent | Merge back earlier cpufreq material. (diff) | |
download | linux-057beb1de54d33ecfd3397ed219b1f4518e3b470.tar.xz linux-057beb1de54d33ecfd3397ed219b1f4518e3b470.zip |
Merge branch 'pm-cpufreq'
* pm-cpufreq: (28 commits)
cpufreq: handle calls to ->target_index() in separate routine
cpufreq: s5pv210: drop check for CONFIG_PM_VERBOSE
cpufreq: intel_pstate: Remove unused member name of cpudata
cpufreq: Break out early when frequency equals target_freq
cpufreq: Tegra: drop wrapper around tegra_update_cpu_speed()
cpufreq: imx6q: Remove unused include
cpufreq: imx6q: Drop devm_clk/regulator_get usage
cpufreq: powernow-k8: Suppress checkpatch warnings
cpufreq: powernv: make local function static
cpufreq: Enable big.LITTLE cpufreq driver on arm64
cpufreq: nforce2: remove DEFINE_PCI_DEVICE_TABLE macro
intel_pstate: Add CPU IDs for Broadwell processors
cpufreq: Fix build error on some platforms that use cpufreq_for_each_*
PM / OPP: Move cpufreq specific OPP functions out of generic OPP library
PM / OPP: Remove cpufreq wrapper dependency on internal data organization
cpufreq: Catch double invocations of cpufreq_freq_transition_begin/end
intel_pstate: Remove sample parameter in intel_pstate_calc_busy
cpufreq: Kconfig: Fix spelling errors
cpufreq: Make linux-pm@vger.kernel.org official mailing list
cpufreq: exynos: Use dev_err/info function instead of pr_err/info
...
Diffstat (limited to 'Documentation/power')
-rw-r--r-- | Documentation/power/opp.txt | 40 |
1 files changed, 5 insertions, 35 deletions
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 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 |