On 02-12-20, 17:23, Nicola Mazzucato wrote:
> By design, SCMI performance domains define the granularity of
> performance controls, they do not describe any underlying hardware
> dependencies (although they may match in many cases).
>
> It is therefore possible to have some platforms where hardware may have
> the ability to control CPU performance at different granularity and choose
> to describe fine-grained performance control through SCMI.
>
> In such situations, the energy model would be provided with inaccurate
> information based on controls, while it still needs to know the
> performance boundaries.
>
> To restore correct functionality, retrieve information of CPUs under the
> same v/f domain from operating-points-v2 in DT, and pass it on to EM.
>
> Signed-off-by: Nicola Mazzucato <nicola.mazzucato@xxxxxxx>
> ---
> drivers/cpufreq/scmi-cpufreq.c | 51 +++++++++++++++++++++++-----------
> 1 file changed, 35 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
> index 491a0a24fb1e..f505efcc62b1 100644
> --- a/drivers/cpufreq/scmi-cpufreq.c
> +++ b/drivers/cpufreq/scmi-cpufreq.c
> @@ -127,6 +127,7 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
> struct cpufreq_frequency_table *freq_table;
> struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
> bool power_scale_mw;
> + cpumask_var_t opp_shared_cpus;
>
> cpu_dev = get_cpu_device(policy->cpu);
> if (!cpu_dev) {
> @@ -134,30 +135,45 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
> return -ENODEV;
> }
>
> - ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
> - if (ret) {
> - dev_warn(cpu_dev, "failed to add opps to the device\n");
> - return ret;
> - }
> + if (!zalloc_cpumask_var(&opp_shared_cpus, GFP_KERNEL))
> + return -ENOMEM;
>
> ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
> if (ret) {
> dev_warn(cpu_dev, "failed to get sharing cpumask\n");
> - return ret;
> + goto out_free_cpumask;
> }
>
> - ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
> - if (ret) {
> - dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
> - __func__, ret);
> - return ret;
> + /*
> + * The OPP 'sharing cpus' info may come from dt through an empty opp
> + * table and opp-shared. If found, it takes precedence over the SCMI
> + * domain IDs info.
> + */
> + ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, opp_shared_cpus);
> + if (ret || !cpumask_weight(opp_shared_cpus)) {
> + /*
> + * Either opp-table is not set or no opp-shared was found,
> + * use the information from SCMI domain IDs.
> + */
> + cpumask_copy(opp_shared_cpus, policy->cpus);
> }
>
> nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
> if (nr_opp <= 0) {
> - dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
> - ret = -EPROBE_DEFER;
> - goto out_free_opp;
> + ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
> + if (ret) {
> + dev_warn(cpu_dev, "failed to add opps to the device\n");
> + goto out_free_cpumask;
> + }
> +
> + ret = dev_pm_opp_set_sharing_cpus(cpu_dev, opp_shared_cpus);
> + if (ret) {
> + dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
> + __func__, ret);
> + goto out_free_cpumask;
> + }
> +
Why do we need to call above two after calling
dev_pm_opp_get_opp_count() ? And we don't check the return value of
the below call anymore, moreover we have to call it twice now.
> + nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
> }
>
> priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> @@ -191,15 +207,18 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
> handle->perf_ops->fast_switch_possible(handle, cpu_dev);
>
> power_scale_mw = handle->perf_ops->power_scale_mw_get(handle);
> - em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus,
> + em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, opp_shared_cpus,
> power_scale_mw);
>
> - return 0;
> + ret = 0;
ret is already 0 here.
> + goto out_free_cpumask;
>
> out_free_priv:
> kfree(priv);
> out_free_opp:
> dev_pm_opp_remove_all_dynamic(cpu_dev);
> +out_free_cpumask:
> + free_cpumask_var(opp_shared_cpus);
>
> return ret;
> }
> --
> 2.27.0
--
viresh
