cpufreq: scmi: Register for limit change notifications

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@quicinc.com>
Tested-by: Mike Tipton <quic_mdtipton@quicinc.com>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index 07d6f9a9b7c82024eafe59b62d2978a031822b18..b8fe758aeb0100ac57038ec8cef2fa7228a94921 100644 (file)
--- 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>
@@ -26,6 +27,8 @@ struct scmi_data {
        int nr_opp;
        struct device *cpu_dev;
        cpumask_var_t opp_shared_cpus;
+       struct notifier_block limit_notify_nb;
+       struct freq_qos_request limits_freq_req;
 };
 
 static struct scmi_protocol_handle *ph;
@@ -174,6 +177,22 @@ 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;
+       unsigned int limit_freq_khz;
+       int ret;
+
+       limit_freq_khz = limit_notify->range_max_freq / HZ_PER_KHZ;
+
+       ret = freq_qos_update_request(&priv->limits_freq_req, limit_freq_khz);
+       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 +200,7 @@ 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 +314,23 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
                }
        }
 
+       ret = freq_qos_add_request(&policy->constraints, &priv->limits_freq_req, FREQ_QOS_MAX,
+                                  FREQ_QOS_MAX_DEFAULT_VALUE);
+       if (ret < 0) {
+               dev_err(cpu_dev, "failed to add qos limits request: %d\n", ret);
+               goto out_free_table;
+       }
+
+       priv->limit_notify_nb.notifier_call = scmi_limit_notify_cb;
+       ret = sdev->handle->notify_ops->event_notifier_register(sdev->handle, SCMI_PROTOCOL_PERF,
+                                                       SCMI_EVENT_PERFORMANCE_LIMITS_CHANGED,
+                                                       &priv->domain_id,
+                                                       &priv->limit_notify_nb);
+       if (ret)
+               dev_warn(&sdev->dev,
+                        "failed to register for limits change notifier for domain %d\n",
+                        priv->domain_id);
+
        return 0;
 
 out_free_table:
@@ -313,7 +350,13 @@ out_free_priv:
 static void scmi_cpufreq_exit(struct cpufreq_policy *policy)
 {
        struct scmi_data *priv = policy->driver_data;
+       struct scmi_device *sdev = cpufreq_get_driver_data();
 
+       sdev->handle->notify_ops->event_notifier_unregister(sdev->handle, SCMI_PROTOCOL_PERF,
+                                                           SCMI_EVENT_PERFORMANCE_LIMITS_CHANGED,
+                                                           &priv->domain_id,
+                                                           &priv->limit_notify_nb);
+       freq_qos_remove_request(&priv->limits_freq_req);
        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);
@@ -372,6 +415,8 @@ 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);