Commit 951fc5f4 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

cpufreq: Update Documentation for cpus and related_cpus 



Documentation related to cpus and related_cpus is confusing and not very clear.
Over that CPUFreq core has seen much changes recently. Lets update documentation
and comments for cpus and related_cpus.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5553f9e2

Documentation/cpu-freq/cpu-drivers.txt

+6 −0
Original line number Diff line number Diff line
@@ -111,6 +111,12 @@ policy->governor must contain the "default policy" for 
For setting some of these values, the frequency table helpers might be

helpful. See the section 2 for more information on them.



SMP systems normally have same clock source for a group of cpus. For these the

.init() would be called only once for the first online cpu. Here the .init()

routine must initialize policy->cpus with mask of all possible cpus (Online +

Offline) that share the clock. Then the core would copy this mask onto

policy->related_cpus and will reset policy->cpus to carry only online cpus.





1.3 verify

------------

Documentation/cpu-freq/user-guide.txt

+4 −4
Original line number Diff line number Diff line
@@ -190,11 +190,11 @@ scaling_max_freq show the current "policy limits" (in 
				first set scaling_max_freq, then

				scaling_min_freq.



affected_cpus :			List of CPUs that require software coordination

				of frequency.

affected_cpus :			List of Online CPUs that require software

				coordination of frequency.



related_cpus :			List of CPUs that need some sort of frequency

				coordination, whether software or hardware.

related_cpus :			List of Online + Offline CPUs that need software

				coordination of frequency.



scaling_driver :		Hardware driver for cpufreq.

include/linux/cpufreq.h

+4 −2
Original line number Diff line number Diff line
@@ -89,8 +89,10 @@ struct cpufreq_real_policy { 
};



struct cpufreq_policy {

	cpumask_var_t		cpus;	/* CPUs requiring sw coordination */

	cpumask_var_t		related_cpus; /* CPUs with any coordination */

	/* CPUs sharing clock, require sw coordination */

	cpumask_var_t		cpus;	/* Online CPUs only */

	cpumask_var_t		related_cpus; /* Online + Offline CPUs */



	unsigned int		shared_type; /* ANY or ALL affected CPUs

						should set cpufreq */

	unsigned int		cpu;    /* cpu nr of CPU managing this policy */

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