diff options
Diffstat (limited to 'Documentation/cpu-freq/core.txt')
| -rw-r--r-- | Documentation/cpu-freq/core.txt | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/Documentation/cpu-freq/core.txt b/Documentation/cpu-freq/core.txt index ba78e7c2a069..978463a7c81e 100644 --- a/Documentation/cpu-freq/core.txt +++ b/Documentation/cpu-freq/core.txt @@ -8,6 +8,8 @@ Dominik Brodowski <linux@brodo.de> David Kimdon <dwhedon@debian.org> + Rafael J. Wysocki <rafael.j.wysocki@intel.com> + Viresh Kumar <viresh.kumar@linaro.org> @@ -36,10 +38,11 @@ speed limits (like LCD drivers on ARM architecture). Additionally, the kernel "constant" loops_per_jiffy is updated on frequency changes here. -Reference counting is done by cpufreq_get_cpu and cpufreq_put_cpu, -which make sure that the cpufreq processor driver is correctly -registered with the core, and will not be unloaded until -cpufreq_put_cpu is called. +Reference counting of the cpufreq policies is done by cpufreq_cpu_get +and cpufreq_cpu_put, which make sure that the cpufreq driver is +correctly registered with the core, and will not be unloaded until +cpufreq_put_cpu is called. That also ensures that the respective cpufreq +policy doesn't get freed while being used. 2. CPUFreq notifiers ==================== @@ -69,18 +72,16 @@ CPUFreq policy notifier is called twice for a policy transition: The phase is specified in the second argument to the notifier. The third argument, a void *pointer, points to a struct cpufreq_policy -consisting of five values: cpu, min, max, policy and max_cpu_freq. min -and max are the lower and upper frequencies (in kHz) of the new -policy, policy the new policy, cpu the number of the affected CPU; and -max_cpu_freq the maximum supported CPU frequency. This value is given -for informational purposes only. +consisting of several values, including min, max (the lower and upper +frequencies (in kHz) of the new policy). 2.2 CPUFreq transition notifiers -------------------------------- -These are notified twice when the CPUfreq driver switches the CPU core -frequency and this change has any external implications. +These are notified twice for each online CPU in the policy, when the +CPUfreq driver switches the CPU core frequency and this change has no +any external implications. The second argument specifies the phase - CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE. @@ -90,13 +91,14 @@ values: cpu - number of the affected CPU old - old frequency new - new frequency +flags - flags of the cpufreq driver 3. CPUFreq Table Generation with Operating Performance Point (OPP) ================================================================== For details about OPP, see Documentation/power/opp.txt dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with - cpufreq_frequency_table_cpuinfo which is provided with the list of + cpufreq_table_validate_and_show() 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 @@ -110,7 +112,7 @@ dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with /* Do things */ r = dev_pm_opp_init_cpufreq_table(dev, &freq_table); if (!r) - cpufreq_frequency_table_cpuinfo(policy, freq_table); + cpufreq_table_validate_and_show(policy, freq_table); /* Do other things */ } |