drm/v3d: Add DRM_IOCTL_V3D_PERFMON_SET_GLOBAL

Add a new ioctl, DRM_IOCTL_V3D_PERFMON_SET_GLOBAL, to allow
configuration of a global performance monitor (perfmon).
Use the global perfmon for all jobs to ensure consistent
performance tracking across submissions. This feature is
needed to implement a Perfetto datasources in user-space.

Signed-off-by: Christian Gmeiner <[email protected]>
Reviewed-by: Maíra Canal <[email protected]>
Signed-off-by: Maíra Canal <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/gpu/drm/v3d/v3d_perfmon.c b/drivers/gpu/drm/v3d/v3d_perfmon.c
index b4c3708ea781..a1429b9684e0 100644
--- a/drivers/gpu/drm/v3d/v3d_perfmon.c
+++ b/drivers/gpu/drm/v3d/v3d_perfmon.c
@@ -313,6 +313,9 @@ static int v3d_perfmon_idr_del(int id, void *elem, void *data)
 	if (perfmon == v3d->active_perfmon)
 		v3d_perfmon_stop(v3d, perfmon, false);
 
+	/* If the global perfmon is being destroyed, set it to NULL */
+	cmpxchg(&v3d->global_perfmon, perfmon, NULL);
+
 	v3d_perfmon_put(perfmon);
 
 	return 0;
@@ -398,6 +401,9 @@ int v3d_perfmon_destroy_ioctl(struct drm_device *dev, void *data,
 	if (perfmon == v3d->active_perfmon)
 		v3d_perfmon_stop(v3d, perfmon, false);
 
+	/* If the global perfmon is being destroyed, set it to NULL */
+	cmpxchg(&v3d->global_perfmon, perfmon, NULL);
+
 	v3d_perfmon_put(perfmon);
 
 	return 0;
@@ -457,3 +463,34 @@ int v3d_perfmon_get_counter_ioctl(struct drm_device *dev, void *data,
 
 	return 0;
 }
+
+int v3d_perfmon_set_global_ioctl(struct drm_device *dev, void *data,
+				 struct drm_file *file_priv)
+{
+	struct v3d_file_priv *v3d_priv = file_priv->driver_priv;
+	struct drm_v3d_perfmon_set_global *req = data;
+	struct v3d_dev *v3d = to_v3d_dev(dev);
+	struct v3d_perfmon *perfmon;
+
+	if (req->flags & ~DRM_V3D_PERFMON_CLEAR_GLOBAL)
+		return -EINVAL;
+
+	perfmon = v3d_perfmon_find(v3d_priv, req->id);
+	if (!perfmon)
+		return -EINVAL;
+
+	/* If the request is to clear the global performance monitor */
+	if (req->flags & DRM_V3D_PERFMON_CLEAR_GLOBAL) {
+		if (!v3d->global_perfmon)
+			return -EINVAL;
+
+		xchg(&v3d->global_perfmon, NULL);
+
+		return 0;
+	}
+
+	if (cmpxchg(&v3d->global_perfmon, NULL, perfmon))
+		return -EBUSY;
+
+	return 0;
+}