[PATCH] drm/nouveau: use different register to wait for secret scrubber to be completed

[Maarten Lankhorst <maarten.lankhorst@canonical.com>]

Fixes long delay when waiting for scrubber on some secret engines.
The exit interrupt seems to not always be generated, so use secret
scrubber active register instead.

Later fuc engines also no longer generate an interrupt, so don't wait there.

---
diff --git a/drivers/gpu/drm/nouveau/core/core/falcon.c b/drivers/gpu/drm/nouveau/core/core/falcon.c
index 6b0843c..e05c157 100644
--- a/drivers/gpu/drm/nouveau/core/core/falcon.c
+++ b/drivers/gpu/drm/nouveau/core/core/falcon.c
@@ -73,8 +73,11 @@ _nouveau_falcon_init(struct nouveau_object *object)
 	nv_debug(falcon, "data limit: %d\n", falcon->data.limit);
 
 	/* wait for 'uc halted' to be signalled before continuing */
-	if (falcon->secret) {
-		nv_wait(falcon, 0x008, 0x00000010, 0x00000010);
+	if (falcon->secret && falcon->version < 4) {
+		if (!falcon->version)
+			nv_wait(falcon, 0x008, 0x00000010, 0x00000010);
+		else
+			nv_wait(falcon, 0x180, 0x80000000, 0);
 		nv_wo32(falcon, 0x004, 0x00000010);
 	}