| Message ID | 20200211184542.29585-6-ionela.voinescu@arm.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | arm64: ARMv8.4 Activity Monitors support | expand |
On 11-02-20, 18:45, Ionela Voinescu wrote: > Add weak function to return the hardware maximum frequency of a > CPU, with the default implementation returning cpuinfo.max_freq. > > The default can be overwritten by a strong function in platforms > that want to provide an alternative implementation. > > Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com> > Cc: Rafael J. Wysocki <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/cpufreq.c | 20 ++++++++++++++++++++ > include/linux/cpufreq.h | 5 +++++ > 2 files changed, 25 insertions(+) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 77114a3897fb..d2ff3018861d 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -1733,6 +1733,26 @@ unsigned int cpufreq_quick_get_max(unsigned int cpu) > } > EXPORT_SYMBOL(cpufreq_quick_get_max); > > +/** > + * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU > + * @cpu: CPU number > + * > + * The default return value is the max_freq field of cpuinfo. > + */ > +__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) > +{ > + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); > + unsigned int ret_freq = 0; > + > + if (policy) { > + ret_freq = policy->cpuinfo.max_freq; > + cpufreq_cpu_put(policy); > + } > + > + return ret_freq; > +} > +EXPORT_SYMBOL(cpufreq_get_hw_max_freq); > + > static unsigned int __cpufreq_get(struct cpufreq_policy *policy) > { > if (unlikely(policy_is_inactive(policy))) > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index 31b1b0e03df8..b4423ff619f4 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -194,6 +194,7 @@ extern struct kobject *cpufreq_global_kobject; > unsigned int cpufreq_get(unsigned int cpu); > unsigned int cpufreq_quick_get(unsigned int cpu); > unsigned int cpufreq_quick_get_max(unsigned int cpu); > +unsigned int cpufreq_get_hw_max_freq(unsigned int cpu); > void disable_cpufreq(void); > > u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy); > @@ -223,6 +224,10 @@ static inline unsigned int cpufreq_quick_get_max(unsigned int cpu) > { > return 0; > } > +static inline unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) > +{ > + return 0; > +} > static inline void disable_cpufreq(void) { } > #endif Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
On 2/11/20 6:45 PM, Ionela Voinescu wrote: > +/** > + * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU > + * @cpu: CPU number > + * > + * The default return value is the max_freq field of cpuinfo. > + */ > +__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) > +{ > + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); > + unsigned int ret_freq = 0; > + > + if (policy) { > + ret_freq = policy->cpuinfo.max_freq; > + cpufreq_cpu_put(policy); What about intel_pstate / turbo stuff? IIRC one of Giovanni's issues was that turbo freq is not always reported as the max freq. Dunno if we can do anything about it; at the very least maybe document the caveat? > + } > + > + return ret_freq; > +} > +EXPORT_SYMBOL(cpufreq_get_hw_max_freq); > + > static unsigned int __cpufreq_get(struct cpufreq_policy *policy) > { > if (unlikely(policy_is_inactive(policy)))
On Thursday 13 Feb 2020 at 11:59:56 (+0000), Valentin Schneider wrote: > On 2/11/20 6:45 PM, Ionela Voinescu wrote: > > +/** > > + * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU > > + * @cpu: CPU number > > + * > > + * The default return value is the max_freq field of cpuinfo. > > + */ > > +__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) > > +{ > > + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); > > + unsigned int ret_freq = 0; > > + > > + if (policy) { > > + ret_freq = policy->cpuinfo.max_freq; > > + cpufreq_cpu_put(policy); > > What about intel_pstate / turbo stuff? IIRC one of Giovanni's issues was that > turbo freq is not always reported as the max freq. Dunno if we can do > anything about it; at the very least maybe document the caveat? > Okay, I can add details in the description in regards to potential reasons to overwrite this function. But basically this is one of the reasons for making this a weak function. The best information we can generically get for maximum hardware frequency is cpuinfo.max_freq. But if platforms have the possibility to obtain this differently from either hardware or firmware they can overwrite this. Thanks, Ionela. > > + } > > + > > + return ret_freq; > > +} > > +EXPORT_SYMBOL(cpufreq_get_hw_max_freq); > > + > > static unsigned int __cpufreq_get(struct cpufreq_policy *policy) > > { > > if (unlikely(policy_is_inactive(policy))) >
On 2/13/20 12:59 PM, Ionela Voinescu wrote: >> What about intel_pstate / turbo stuff? IIRC one of Giovanni's issues was that >> turbo freq is not always reported as the max freq. Dunno if we can do >> anything about it; at the very least maybe document the caveat? >> > > Okay, I can add details in the description in regards to potential > reasons to overwrite this function. But basically this is one of the > reasons for making this a weak function. The best information we can > generically get for maximum hardware frequency is cpuinfo.max_freq. > But if platforms have the possibility to obtain this differently from > either hardware or firmware they can overwrite this. > Right, that would be handled by a different implementation of that function, so this wasn't too relevant of a comment. Sorry!
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 77114a3897fb..d2ff3018861d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1733,6 +1733,26 @@ unsigned int cpufreq_quick_get_max(unsigned int cpu) } EXPORT_SYMBOL(cpufreq_quick_get_max); +/** + * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU + * @cpu: CPU number + * + * The default return value is the max_freq field of cpuinfo. + */ +__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) +{ + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + unsigned int ret_freq = 0; + + if (policy) { + ret_freq = policy->cpuinfo.max_freq; + cpufreq_cpu_put(policy); + } + + return ret_freq; +} +EXPORT_SYMBOL(cpufreq_get_hw_max_freq); + static unsigned int __cpufreq_get(struct cpufreq_policy *policy) { if (unlikely(policy_is_inactive(policy))) diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 31b1b0e03df8..b4423ff619f4 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -194,6 +194,7 @@ extern struct kobject *cpufreq_global_kobject; unsigned int cpufreq_get(unsigned int cpu); unsigned int cpufreq_quick_get(unsigned int cpu); unsigned int cpufreq_quick_get_max(unsigned int cpu); +unsigned int cpufreq_get_hw_max_freq(unsigned int cpu); void disable_cpufreq(void); u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy); @@ -223,6 +224,10 @@ static inline unsigned int cpufreq_quick_get_max(unsigned int cpu) { return 0; } +static inline unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) +{ + return 0; +} static inline void disable_cpufreq(void) { } #endif
Add weak function to return the hardware maximum frequency of a CPU, with the default implementation returning cpuinfo.max_freq. The default can be overwritten by a strong function in platforms that want to provide an alternative implementation. Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/cpufreq.c | 20 ++++++++++++++++++++ include/linux/cpufreq.h | 5 +++++ 2 files changed, 25 insertions(+)