On 22/03/2024 12:08, Lukasz Luba wrote:
> diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
> index 6960dd7393b2d..f7f7ae34ec552 100644
> --- a/kernel/power/energy_model.c
> +++ b/kernel/power/energy_model.c
> @@ -808,3 +808,54 @@ static void em_update_workfn(struct work_struct *work)
> {
> em_check_capacity_update();
> }
> +
> +/**
> + * em_dev_update_chip_binning() - Update Energy Model with new values after
s/with new values// ... IMHO this should be obvious ?
> + * the new voltage information is present in the OPPs.
> + * @dev : Device for which the Energy Model has to be updated.
> + *
> + * This function allows to update easily the EM with new values available in
> + * the OPP framework and DT. It can be used after the chip has been properly
> + * verified by device drivers and the voltages adjusted for the 'chip binning'.
> + * It uses the "dynamic-power-coefficient" DT property to calculate the power
> + * values for EM. For power calculation it uses the new adjusted voltage
> + * values known for OPPs, which might be changed after boot.
The last two sentences describe what dev_pm_opp_calc_power() is doing.
Maybe this can be made clearer here?
> + */
> +int em_dev_update_chip_binning(struct device *dev)
This is the old dev_pm_opp_of_update_em() right?
> +{
> + struct em_perf_table __rcu *em_table;
> + struct em_perf_domain *pd;
> + int i, ret;
> +
> + if (IS_ERR_OR_NULL(dev))
> + return -EINVAL;
When do you use if '(IS_ERR_OR_NULL(dev))' and when 'if(!dev)' for EM
interface functions?
> + pd = em_pd_get(dev);
> + if (!pd) {
> + dev_warn(dev, "Couldn't find Energy Model\n");
> + return -EINVAL;
> + }
> +
> + em_table = em_table_dup(pd);
> + if (!em_table) {
> + dev_warn(dev, "EM: allocation failed\n");
> + return -ENOMEM;
> + }
> +
> + /* Update power values which might change due to new voltage in OPPs */
> + for (i = 0; i < pd->nr_perf_states; i++) {
> + unsigned long freq = em_table->state[i].frequency;
> + unsigned long power;
> +
> + ret = dev_pm_opp_calc_power(dev, &power, &freq);
> + if (ret) {
> + em_table_free(em_table);
> + return ret;
> + }
> +
> + em_table->state[i].power = power;
> + }
> +
> + return em_recalc_and_update(dev, pd, em_table);
> +}
> +EXPORT_SYMBOL_GPL(em_dev_update_chip_binning);
In the previous version of 'chip-binning' you were using the new EM
interface em_dev_compute_costs() (1) which is now replaced by
em_recalc_and_update() -> em_compute_costs().
https://lkml.kernel.org/r/20231220110339.1065505-2-lukasz.luba@xxxxxxx
Which leaves (1) still unused.
That was why my concern back then that we shouldn't introduce EM
interfaces without a user:
https://lkml.kernel.org/r/8fc499cf-fca1-4465-bff7-a93dfd36f3c8@xxxxxxx
What happens now with em_dev_compute_costs()?
