drm/xe/pmu: Add GT C6 events

Provide a PMU interface for GT C6 residency counters. The interface is
similar to the one available for i915, but gt is passed in the config
when creating the event.

Sample usage and output:

$ perf list | grep gt-c6
xe_0000_00_02.0/gt-c6-residency/ [Kernel PMU event]

$ tail /sys/bus/event_source/devices/xe_0000_00_02.0/events/gt-c6-residency*
==> /sys/bus/event_source/devices/xe_0000_00_02.0/events/gt-c6-residency <==
event=0x01

==> /sys/bus/event_source/devices/xe_0000_00_02.0/events/gt-c6-residency.unit <==
ms

$ perf stat -e xe_0000_00_02.0/gt-c6-residency,gt=0/ -I1000
# time counts unit events
1.001196056 1,001 ms xe_0000_00_02.0/gt-c6-residency,gt=0/
2.005216219 1,003 ms xe_0000_00_02.0/gt-c6-residency,gt=0/

Reviewed-by: Rodrigo Vivi <[e-mail]>
Reviewed-by: Riana Tauro <[e-mail]>
Signed-off-by: Vinay Belgaumkar <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Lucas De Marchi <[e-mail]>

drivers/gpu/drm/xe/xe_pmu.c

···
 #include <linux/device.h>
 
 #include "xe_device.h"
+#include "xe_gt_idle.h"
 #include "xe_pm.h"
 #include "xe_pmu.h"
 
···
 {
 	return FIELD_GET(XE_PMU_EVENT_GT_MASK, config);
 }
+
+#define XE_PMU_EVENT_GT_C6_RESIDENCY	0x01
 
 static struct xe_gt *event_to_gt(struct perf_event *event)
 {
···
 static u64 __xe_pmu_event_read(struct perf_event *event)
 {
 	struct xe_gt *gt = event_to_gt(event);
-	u64 val = 0;
 
 	if (!gt)
 		return 0;
 
-	return val;
+	switch (config_to_event_id(event->attr.config)) {
+	case XE_PMU_EVENT_GT_C6_RESIDENCY:
+		return xe_gt_idle_residency_msec(&gt->gtidle);
+	}
+
+	return 0;
 }
 
 static void xe_pmu_event_update(struct perf_event *event)
···
 	.attrs = pmu_format_attrs,
 };
 
-__maybe_unused static ssize_t event_attr_show(struct device *dev,
-					      struct device_attribute *attr, char *buf)
+static ssize_t event_attr_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
 {
 	struct perf_pmu_events_attr *pmu_attr =
 		container_of(attr, struct perf_pmu_events_attr, attr);
···
 	XE_EVENT_ATTR(name_, v_, id_)					\
 	XE_EVENT_ATTR_GROUP(v_, id_, &pmu_event_ ##v_.attr.attr)
 
+XE_EVENT_ATTR_SIMPLE(gt-c6-residency, gt_c6_residency, XE_PMU_EVENT_GT_C6_RESIDENCY, "ms");
+
 static struct attribute *pmu_empty_event_attrs[] = {
 	/* Empty - all events are added as groups with .attr_update() */
 	NULL,
···
 };
 
 static const struct attribute_group *pmu_events_attr_update[] = {
-	/* No events yet */
+	&pmu_group_gt_c6_residency,
 	NULL,
 };
 
 static void set_supported_events(struct xe_pmu *pmu)
 {
+	struct xe_device *xe = container_of(pmu, typeof(*xe), pmu);
+
+	if (!xe->info.skip_guc_pc)
+		pmu->supported_events |= BIT_ULL(XE_PMU_EVENT_GT_C6_RESIDENCY);
 }
 
 /**