On 5/28/24 14:38, Vincent Guittot wrote:
Hi Sibi,
Hey Vincent, Thanks for taking time to review the series :)
On Thu, 28 Mar 2024 at 08:42, 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> --- v4: * Use a interim variable to show the khz calc. [Lukasz] * Use driver_data to pass on the handle and scmi_dev instead of using global variables. Dropped Lukasz's Rb due to adding these minor changes. drivers/cpufreq/scmi-cpufreq.c | 44 ++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c index 3b4f6bfb2f4c..d946b7a08258 100644 --- a/drivers/cpufreq/scmi-cpufreq.c +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -21,11 +21,18 @@ #include <linux/types.h> #include <linux/units.h> +struct scmi_cpufreq_driver_data { + struct scmi_device *sdev; + const struct scmi_handle *handle; +}; + 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 +181,22 @@ 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; + struct cpufreq_policy *policy = priv->policy; + unsigned int limit_freq_khz; + + 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); + + cpufreq_update_pressure(policy);I noticed your patch while looking for other things in the archive but I don't think this is the right way to do it. cpufreq_update_pressure() aims to set to the scheduler the aggregation of all cappings set to cpufreq through the pm_qos and freq_qos_add_request(). Calling this function directly in scmi notification callback will overwrite the pm_qos aggregation. And at the opposite, any update of a pm_qos constraint will overwrite scmi notification. Instead you should better set a pm_qos constraint like others
Sure, I'll drop update_pressue and use the freq_qos_update_request to update the policy->max_freq_req with the new policy->max. -Sibi
+ + return NOTIFY_OK; +} + static int scmi_cpufreq_init(struct cpufreq_policy *policy) { int ret, nr_opp, domain; @@ -181,6 +204,7 @@ 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_cpufreq_driver_data *data = cpufreq_get_driver_data(); cpu_dev = get_cpu_device(policy->cpu); if (!cpu_dev) { @@ -294,6 +318,17 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy) } } + priv->limit_notify_nb.notifier_call = scmi_limit_notify_cb; + ret = data->handle->notify_ops->devm_event_notifier_register(data->sdev, SCMI_PROTOCOL_PERF, + SCMI_EVENT_PERFORMANCE_LIMITS_CHANGED, + &domain, + &priv->limit_notify_nb); + if (ret) + dev_warn(cpu_dev, + "failed to register for limits change notifier for domain %d\n", domain); + + priv->policy = policy; + return 0; out_free_opp: @@ -366,12 +401,21 @@ static int scmi_cpufreq_probe(struct scmi_device *sdev) int ret; struct device *dev = &sdev->dev; const struct scmi_handle *handle; + struct scmi_cpufreq_driver_data *data; handle = sdev->handle; if (!handle) return -ENODEV; + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->sdev = sdev; + data->handle = handle; + scmi_cpufreq_driver.driver_data = data; + perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph); if (IS_ERR(perf_ops)) return PTR_ERR(perf_ops); -- 2.34.1
