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>

4 files changed, 46 insertions, 0 deletions

diff --git a/drivers/platform/x86/intel/pmt/Kconfig b/drivers/platform/x86/intel/pmt/Kconfig
index 0ad91b5112e9..83ae17eab462 100644
--- a/drivers/platform/x86/intel/pmt/Kconfig
+++ b/drivers/platform/x86/intel/pmt/Kconfig
@@ -18,6 +18,7 @@ config INTEL_PMT_CLASS
 config INTEL_PMT_TELEMETRY
 	tristate "Intel Platform Monitoring Technology (PMT) Telemetry driver"
 	depends on INTEL_VSEC
+	select INTEL_PMT_DISCOVERY
 	select INTEL_PMT_CLASS
 	help
 	  The Intel Platform Monitory Technology (PMT) Telemetry driver provides
diff --git a/drivers/platform/x86/intel/pmt/class.h b/drivers/platform/x86/intel/pmt/class.h
index 39c32357ee2c..fdf7e79d8c0d 100644
--- a/drivers/platform/x86/intel/pmt/class.h
+++ b/drivers/platform/x86/intel/pmt/class.h
@@ -48,6 +48,7 @@ struct intel_pmt_entry {
 	struct pmt_callbacks	*cb;
 	unsigned long		base_addr;
 	size_t			size;
+	u64			feature_flags;
 	u32			guid;
 	u32			num_rmids; /* Number of Resource Monitoring IDs */
 	int			devid;
@@ -71,4 +72,10 @@ int intel_pmt_dev_create(struct intel_pmt_entry *entry,
 			 struct intel_vsec_device *dev, int idx);
 void intel_pmt_dev_destroy(struct intel_pmt_entry *entry,
 			   struct intel_pmt_namespace *ns);
+#if IS_ENABLED(CONFIG_INTEL_PMT_DISCOVERY)
+void intel_pmt_get_features(struct intel_pmt_entry *entry);
+#else
+static inline void intel_pmt_get_features(struct intel_pmt_entry *entry) {}
+#endif
+
 #endif
diff --git a/drivers/platform/x86/intel/pmt/discovery.c b/drivers/platform/x86/intel/pmt/discovery.c
index 4b4fa3137ad2..e72d43b675b4 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" },
 	{}
diff --git a/drivers/platform/x86/intel/pmt/telemetry.c b/drivers/platform/x86/intel/pmt/telemetry.c
index ac3a9bdf5601..58d06749e417 100644
--- a/drivers/platform/x86/intel/pmt/telemetry.c
+++ b/drivers/platform/x86/intel/pmt/telemetry.c
@@ -9,11 +9,14 @@
  */
 
 #include <linux/auxiliary_bus.h>
+#include <linux/intel_pmt_features.h>
 #include <linux/intel_vsec.h>
 #include <linux/kernel.h>
+#include <linux/kref.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
+#include <linux/types.h>
 #include <linux/uaccess.h>
 #include <linux/overflow.h>
 
@@ -311,6 +314,8 @@ static int pmt_telem_probe(struct auxiliary_device *auxdev, const struct auxilia
 			continue;
 
 		priv->num_entries++;
+
+		intel_pmt_get_features(entry);
 	}
 
 	return 0;