[PATCH 3/3] cpufreq: scmi: Register for limit change notifications

Sibi Sankar
2024-01-08T14:01:59Z

Register for limit change notifications if supported with the help of
perf_notify_support interface and determine the throttled frequency
using the perf_opp_xlate to apply HW pressure.

Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
---
drivers/cpufreq/scmi-cpufreq.c | 42 +++++++++++++++++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index 4ee23f4ebf4a..53bc8868455d 100644
--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c
@@ -25,9 +25,13 @@ 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;
};

+const struct scmi_handle *handle;
+static struct scmi_device *scmi_dev;
static struct scmi_protocol_handle *ph;
static const struct scmi_perf_proto_ops *perf_ops;

@@ -144,6 +148,22 @@ scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power,
return 0;
}

+static int scmi_limit_notify_cb(struct notifier_block *nb, unsigned long event, void *data)
+{
+ unsigned long freq_hz;
+ struct scmi_perf_limits_report *limit_notify = data;
+ struct scmi_data *priv = container_of(nb, struct scmi_data, limit_notify_nb);
+ struct cpufreq_policy *policy = priv->policy;
+
+ if (perf_ops->perf_opp_xlate(ph, priv->domain_id, limit_notify->range_max, &freq_hz))
+ return NOTIFY_OK;
+
+ /* Update HW pressure (the boost frequencies are accepted) */
+ arch_update_hw_pressure(policy->related_cpus, (freq_hz / HZ_PER_KHZ));
+
+ return NOTIFY_OK;
+}
+
static int scmi_cpufreq_init(struct cpufreq_policy *policy)
{
int ret, nr_opp, domain;
@@ -151,6 +171,7 @@ 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_perf_notify_info info = {};

cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
@@ -250,6 +271,25 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
policy->fast_switch_possible =
perf_ops->fast_switch_possible(ph, domain);

+ ret = perf_ops->perf_notify_support(ph, domain, &info);
+ if (ret)
+ dev_warn(cpu_dev, "failed to get supported notifications: %d\n", ret);
+
+ if (info.perf_limit_notify) {
+ priv->limit_notify_nb.notifier_call = scmi_limit_notify_cb;
+ ret = handle->notify_ops->devm_event_notifier_register(scmi_dev, SCMI_PROTOCOL_PERF,
+ SCMI_EVENT_PERFORMANCE_LIMITS_CHANGED,
+ &domain,
+ &priv->limit_notify_nb);
+ if (ret) {
+ dev_err(cpu_dev, "Error in registering limit change notifier for domain %d\n",
+ domain);
+ return ret;
+ }
+ }
+
+ priv->policy = policy;
+
return 0;

out_free_opp:
@@ -321,8 +361,8 @@ static int scmi_cpufreq_probe(struct scmi_device *sdev)
{
int ret;
struct device *dev = &sdev->dev;
- const struct scmi_handle *handle;

+ scmi_dev = sdev;
handle = sdev->handle;

if (!handle)
--
2.17.1