Hi Quentin, On Mon, Dec 03, 2018 at 09:56:28AM +0000, Quentin Perret wrote: > ******************************************************************* > * This patch illustrates the usage of the newly introduced Energy * > * Model framework and isn't supposed to be merged as-is. * > ******************************************************************* > > The Energy Model framework provides an API to register the active power > of CPUs. Call this API from the cpufreq-dt driver with an estimation > of the power as P = C * V^2 * f with C, V, and f respectively the > capacitance of the CPU and the voltage and frequency of the OPP. > > The CPU capacitance is read from the "dynamic-power-coefficient" DT > binding (originally introduced for thermal/IPA), and the voltage and > frequency values from PM_OPP. > > Cc: "Rafael J. Wysocki" <[email protected]> > Cc: Viresh Kumar <[email protected]> > Signed-off-by: Quentin Perret <[email protected]> > --- > drivers/cpufreq/cpufreq-dt.c | 48 +++++++++++++++++++++++++++++++++++- > 1 file changed, 47 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c > index e58bfcb1169e..4cfef5554d86 100644 > --- a/drivers/cpufreq/cpufreq-dt.c > +++ b/drivers/cpufreq/cpufreq-dt.c > @@ -16,6 +16,7 @@ > #include <linux/cpu_cooling.h> > #include <linux/cpufreq.h> > #include <linux/cpumask.h> > +#include <linux/energy_model.h> > #include <linux/err.h> > #include <linux/module.h> > #include <linux/of.h> > @@ -150,8 +151,50 @@ static int resources_available(void) > return 0; > } > > +static int __maybe_unused of_est_power(unsigned long *mW, unsigned long *KHz, > + int cpu) > +{ > + unsigned long mV, Hz, MHz; > + struct device *cpu_dev; > + struct dev_pm_opp *opp; > + struct device_node *np; > + u32 cap; > + u64 tmp; > + > + cpu_dev = get_cpu_device(cpu); > + if (!cpu_dev) > + return -ENODEV; > + > + np = of_node_get(cpu_dev->of_node); > + if (!np) > + return -EINVAL; > + > + if (of_property_read_u32(np, "dynamic-power-coefficient", &cap)) > + return -EINVAL; > + > + Hz = *KHz * 1000; > + opp = dev_pm_opp_find_freq_ceil(cpu_dev, &Hz); > + if (IS_ERR(opp)) > + return -EINVAL; > + > + mV = dev_pm_opp_get_voltage(opp) / 1000; > + dev_pm_opp_put(opp); > + if (!mV) > + return -EINVAL; > + > + MHz = Hz / 1000000; > + tmp = (u64)cap * mV * mV * MHz; > + do_div(tmp, 1000000000); > + > + *mW = (unsigned long)tmp; > + *KHz = Hz / 1000; > + > + return 0; > +} > + > static int cpufreq_init(struct cpufreq_policy *policy) > { > + struct em_data_callback em_cb = EM_DATA_CB(of_est_power); > struct cpufreq_frequency_table *freq_table; > struct opp_table *opp_table = NULL; > struct private_data *priv; > @@ -160,7 +203,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) > unsigned int transition_latency; > bool fallback = false; > const char *name; > - int ret; > + int ret, nr_opp; > > cpu_dev = get_cpu_device(policy->cpu); > if (!cpu_dev) { > @@ -237,6 +280,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) > ret = -EPROBE_DEFER; > goto out_free_opp; > } > + nr_opp = ret; > > if (fallback) { > cpumask_setall(policy->cpus); > @@ -280,6 +324,8 @@ static int cpufreq_init(struct cpufreq_policy *policy) > policy->cpuinfo.transition_latency = transition_latency; > policy->dvfs_possible_from_any_cpu = true; > > + em_register_perf_domain(policy->cpus, nr_opp, &em_cb);
Shouldn't there also be a function to unregister a perf domain to be called from cpufreq_exit()? ->exit() is called on suspend when the CPUs are taken offline, and ->init() on resume, hence em_register_perf_domain() is called multiple times, but without doing any cleanup. Cheers Matthias
