platform/x86/intel/pmt/discovery: Get telemetry attributes

Add intel_pmt_get_features() in PMT Discovery to enable the PMT Telemetry
driver to obtain attributes of the aggregated telemetry spaces it
enumerates. The function gathers feature flags and associated data (like
the number of RMIDs) from each PMT entry, laying the groundwork for a
future kernel interface that will allow direct access to telemetry regions
based on their capabilities.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20250703022832.1302928-14-david.e.box@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/platform/x86/intel/pmt/discovery.c b/drivers/platform/x86/intel/pmt/discovery.c
index 4b4fa3137ad2e..e72d43b675b46 100644
--- a/drivers/platform/x86/intel/pmt/discovery.c
+++ b/drivers/platform/x86/intel/pmt/discovery.c
@@ -583,6 +583,39 @@ abort_probe:
 	return ret;
 }
 
+static void pmt_get_features(struct intel_pmt_entry *entry, struct feature *f)
+{
+	int num_guids = f->table.header.num_guids;
+	int i;
+
+	for (i = 0; i < num_guids; i++) {
+		if (f->table.guids[i] != entry->guid)
+			continue;
+
+		entry->feature_flags |= BIT(f->id);
+
+		if (feature_layout[f->id] == LAYOUT_RMID)
+			entry->num_rmids = f->table.rmid.num_rmids;
+		else
+			entry->num_rmids = 0; /* entry is kzalloc but set anyway */
+	}
+}
+
+void intel_pmt_get_features(struct intel_pmt_entry *entry)
+{
+	struct feature *feature;
+
+	mutex_lock(&feature_list_lock);
+	list_for_each_entry(feature, &pmt_feature_list, list) {
+		if (feature->priv->parent != &entry->ep->pcidev->dev)
+			continue;
+
+		pmt_get_features(entry, feature);
+	}
+	mutex_unlock(&feature_list_lock);
+}
+EXPORT_SYMBOL_NS_GPL(intel_pmt_get_features, "INTEL_PMT");
+
 static const struct auxiliary_device_id pmt_features_id_table[] = {
 	{ .name = "intel_vsec.discovery" },
 	{}