Hi Matthias, On Monday 28 Jan 2019 at 11:02:51 (-0800), Matthias Kaehlcke wrote: > > +/** > > + * of_dev_pm_opp_get_cpu_power() - Estimates the power of a CPU > > + * @mW: pointer to the power estimate in milli-watts > > + * @KHz: pointer to the OPP's frequency, in kilo-hertz > > nit: should be kHz Right, I can change that :-) > > > + * @cpu: CPU for which power needs to be estimated > > + * > > + * Computes the power estimated by @CPU at the first OPP above @KHz (ceil), > > + * and updates @KHz and @mW accordingly. > > + * > > + * The power is estimated as P = C * V^2 * f, with C the CPU's capacitance > > + * (read from the 'dynamic-power-coefficient' devicetree binding) and V and f > > + * respectively the voltage and frequency of the OPP. > > + * > > + * Return: -ENODEV if the CPU device cannot be found, -EINVAL if the power > > + * calculation failed because of missing parameters, 0 otherwise. > > + */ > > +int of_dev_pm_opp_get_cpu_power(unsigned long *mW, unsigned long *KHz, int cpu) > > I think it is more common to put the input parameters first, then the > output ones, i.e. cpu, kHz, mW. Hmm, the issue is this must match the expectations of the EM framework: https://elixir.bootlin.com/linux/v5.0-rc4/source/include/linux/energy_model.h#L62 So, I don't really have a choice. Or we can change the core code if this _really_ is a problem -- we don't have users yet so now is the best time to do so I guess ... > > > +{ > > + unsigned long mV, Hz, MHz; > > + struct device *cpu_dev; > > + struct dev_pm_opp *opp; > > + struct device_node *np; > > + u32 cap; > > + u64 tmp; > > + int ret; > > + > > + cpu_dev = get_cpu_device(cpu); > > + if (!cpu_dev) > > + return -ENODEV; > > + > > + np = of_node_get(cpu_dev->of_node); > > + if (!np) > > + return -EINVAL; > > + > > + ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap); > > + of_node_put(np); > > + if (ret) > > + 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; > > +} > > +EXPORT_SYMBOL_GPL(of_dev_pm_opp_get_cpu_power); > > diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h > > index 0a2a88e5a383..fedde14f5187 100644 > > --- a/include/linux/pm_opp.h > > +++ b/include/linux/pm_opp.h > > @@ -322,6 +322,7 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpuma > > struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev); > > struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp); > > int of_get_required_opp_performance_state(struct device_node *np, int index); > > +int of_dev_pm_opp_get_cpu_power(unsigned long *mW, unsigned long *KHz, int cpu); > > #else > > static inline int dev_pm_opp_of_add_table(struct device *dev) > > { > > @@ -364,6 +365,10 @@ static inline int of_get_required_opp_performance_state(struct device_node *np, > > { > > return -ENOTSUPP; > > } > > +static inline int of_dev_pm_opp_get_cpu_power(unsigned long *mW, unsigned long *KHz, int cpu) > > +{ > > + return -ENOTSUPP; > > +} > > #endif > > > > #endif /* __LINUX_OPP_H__ */ > > Besides the nits above: > > Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > Tested-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> Thank you ! Quentin
