On Tue, Jun 04, 2024 at 12:56:54AM +0530, Sibi Sankar 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>
> ---
>
> v5:
> * Drop patch 1 and use pm_qos to update constraints. [Vincent]
> * Use sdev instead of cpu_dev in dev_warn. [Christian]
> * Pass sdev directly through private data. [Christian]
> * Dropping Rb's for now.
>
> drivers/cpufreq/scmi-cpufreq.c | 36 ++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
Tested-by: Mike Tipton <quic_mdtipton@xxxxxxxxxxx>
>
> diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
> index b87fd127aa43..0edfa55d8e49 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 (ret < 0)
> + pr_warn("failed to update freq constraint: %d\n", ret);
This would be better as a dev_warn() with the cpu device. Other than
that, looks good to me.
