drm/etnaviv: export client GPU usage statistics via fdinfo

This exposes a accumulated GPU active time per client via the
fdinfo infrastructure.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_drv.c

@@ -22,6 +22,7 @@
 #include "etnaviv_gem.h"
 #include "etnaviv_mmu.h"
 #include "etnaviv_perfmon.h"
+#include "common.xml.h"
 
 /*
  * DRM operations:
@@ -475,7 +476,47 @@ static const struct drm_ioctl_desc etnaviv_ioctls[] = {
 	ETNA_IOCTL(PM_QUERY_SIG, pm_query_sig, DRM_RENDER_ALLOW),
 };
 
-DEFINE_DRM_GEM_FOPS(fops);
+static void etnaviv_fop_show_fdinfo(struct seq_file *m, struct file *f)
+{
+	struct drm_file *file = f->private_data;
+	struct drm_device *dev = file->minor->dev;
+	struct etnaviv_drm_private *priv = dev->dev_private;
+	struct etnaviv_file_private *ctx = file->driver_priv;
+
+	/*
+	 * For a description of the text output format used here, see
+	 * Documentation/gpu/drm-usage-stats.rst.
+	 */
+	seq_printf(m, "drm-driver:\t%s\n", dev->driver->name);
+	seq_printf(m, "drm-client-id:\t%u\n", ctx->id);
+
+	for (int i = 0; i < ETNA_MAX_PIPES; i++) {
+		struct etnaviv_gpu *gpu = priv->gpu[i];
+		char engine[10] = "UNK";
+		int cur = 0;
+
+		if (!gpu)
+			continue;
+
+		if (gpu->identity.features & chipFeatures_PIPE_2D)
+			cur = snprintf(engine, sizeof(engine), "2D");
+		if (gpu->identity.features & chipFeatures_PIPE_3D)
+			cur = snprintf(engine + cur, sizeof(engine) - cur,
+				       "%s3D", cur ? "/" : "");
+		if (gpu->identity.nn_core_count > 0)
+			cur = snprintf(engine + cur, sizeof(engine) - cur,
+				       "%sNN", cur ? "/" : "");
+
+		seq_printf(m, "drm-engine-%s:\t%llu ns\n", engine,
+			   ctx->sched_entity[i].elapsed_ns);
+	}
+}
+
+static const struct file_operations fops = {
+	.owner = THIS_MODULE,
+	DRM_GEM_FOPS,
+	.show_fdinfo = etnaviv_fop_show_fdinfo,
+};
 
 static const struct drm_driver etnaviv_drm_driver = {
 	.driver_features    = DRIVER_GEM | DRIVER_RENDER,