On 10/30/24 20:17, Vincent Guittot wrote:
On Wed, 30 Oct 2024 at 14:32, Sibi Sankar <quic_sibis@xxxxxxxxxxx> wrote:Register for limit change notifications if supported and use the throttled frequency from the notification to apply HW pressure. Signed-off-by: Sibi Sankar <quic_sibis@xxxxxxxxxxx> Tested-by: Mike Tipton <quic_mdtipton@xxxxxxxxxxx> Reviewed-by: Cristian Marussi <cristian.marussi@xxxxxxx> Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx> --- v6: * Unregister the notifier in the exit path to make sure the cpus work across suspend/resume cycles. drivers/cpufreq/scmi-cpufreq.c | 38 ++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c index 5892c73e129d..fb3534eae722 100644 --- a/drivers/cpufreq/scmi-cpufreq.c +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -16,6 +16,7 @@ #include <linux/export.h> #include <linux/module.h> #include <linux/pm_opp.h> +#include <linux/pm_qos.h> #include <linux/slab.h> #include <linux/scmi_protocol.h> #include <linux/types.h> @@ -25,7 +26,9 @@ struct scmi_data { int domain_id; int nr_opp; struct device *cpu_dev; + struct cpufreq_policy *policy; cpumask_var_t opp_shared_cpus; + struct notifier_block limit_notify_nb; }; static struct scmi_protocol_handle *ph; @@ -174,6 +177,25 @@ static struct freq_attr *scmi_cpufreq_hw_attr[] = { NULL, }; +static int scmi_limit_notify_cb(struct notifier_block *nb, unsigned long event, void *data) +{ + struct scmi_data *priv = container_of(nb, struct scmi_data, limit_notify_nb); + struct scmi_perf_limits_report *limit_notify = data; + struct cpufreq_policy *policy = priv->policy; + unsigned int limit_freq_khz; + int ret; + + limit_freq_khz = limit_notify->range_max_freq / HZ_PER_KHZ; + + policy->max = clamp(limit_freq_khz, policy->cpuinfo.min_freq, policy->cpuinfo.max_freq); + + ret = freq_qos_update_request(policy->max_freq_req, policy->max);If I don't get it wrong, you are using policy->max_freq_req which is also used by the sysfs scaling_max_freq This means that your request will be overwritten by the next write into scaling_max_freq and/or you will overwrite a constraint set by userspace. You have to create your own freq_qos_request and add it to the list of cpufreq qos request
Thanks for catching this. Will get it fixed in the next re-spin. -Sibi
+ if (ret < 0) + pr_warn("failed to update freq constraint: %d\n", ret); + + return NOTIFY_OK; +} + static int scmi_cpufreq_init(struct cpufreq_policy *policy) { int ret, nr_opp, domain; @@ -181,6 +203,7 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy) struct device *cpu_dev; struct scmi_data *priv; struct cpufreq_frequency_table *freq_table; + struct scmi_device *sdev = cpufreq_get_driver_data(); cpu_dev = get_cpu_device(policy->cpu); if (!cpu_dev) { @@ -294,6 +317,17 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy) } } + priv->limit_notify_nb.notifier_call = scmi_limit_notify_cb; + ret = sdev->handle->notify_ops->devm_event_notifier_register(sdev, SCMI_PROTOCOL_PERF, + SCMI_EVENT_PERFORMANCE_LIMITS_CHANGED, + &domain, + &priv->limit_notify_nb); + if (ret) + dev_warn(&sdev->dev, + "failed to register for limits change notifier for domain %d\n", domain); + + priv->policy = policy; + return 0; out_free_opp: @@ -310,8 +344,10 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy) static void scmi_cpufreq_exit(struct cpufreq_policy *policy) { + struct scmi_device *sdev = cpufreq_get_driver_data(); struct scmi_data *priv = policy->driver_data; + sdev->handle->notify_ops->devm_event_notifier_unregister(sdev, &priv->limit_notify_nb); dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); dev_pm_opp_remove_all_dynamic(priv->cpu_dev); free_cpumask_var(priv->opp_shared_cpus); @@ -370,6 +406,8 @@ static int scmi_cpufreq_probe(struct scmi_device *sdev) if (!handle) return -ENODEV; + scmi_cpufreq_driver.driver_data = sdev; + perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph); if (IS_ERR(perf_ops)) return PTR_ERR(perf_ops); -- 2.34.1
