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: Viresh Kumar viresh.kumar@linaro.org --- Documentation/cpu-freq/cpu-drivers.txt | 6 ++++++ Documentation/cpu-freq/user-guide.txt | 8 ++++---- include/linux/cpufreq.h | 6 ++++-- 3 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt index c436096..72f70b1 100644 --- a/Documentation/cpu-freq/cpu-drivers.txt +++ b/Documentation/cpu-freq/cpu-drivers.txt @@ -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 ------------ diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index 04f6b32..ff2f283 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -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.
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index b60f6ba..04d2e84 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -86,8 +86,10 @@ 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 registered CPU */