drm/nouveau/kms/nv50-: create heads based on nvkm head mask

No need to go poking HW directly, and probably shouldn't on GSP-RM.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Danilo Krummrich <me@dakr.org>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919220442.202488-40-lyude@redhat.com

drivers/gpu/drm/nouveau/dispnv50/disp.c

@@ -2692,13 +2692,12 @@ nv50_display_destroy(struct drm_device *dev)
 int
 nv50_display_create(struct drm_device *dev)
 {
-	struct nvif_device *device = &nouveau_drm(dev)->client.device;
 	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct dcb_table *dcb = &drm->vbios.dcb;
 	struct drm_connector *connector, *tmp;
 	struct nv50_disp *disp;
 	struct dcb_output *dcbe;
-	int crtcs, ret, i;
+	int ret, i;
 	bool has_mst = nv50_has_mst(drm);
 
 	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
@@ -2776,20 +2775,9 @@ nv50_display_create(struct drm_device *dev)
 	}
 
 	/* create crtc objects to represent the hw heads */
-	if (disp->disp->object.oclass >= GV100_DISP)
-		crtcs = nvif_rd32(&device->object, 0x610060) & 0xff;
-	else
-	if (disp->disp->object.oclass >= GF110_DISP)
-		crtcs = nvif_rd32(&device->object, 0x612004) & 0xf;
-	else
-		crtcs = 0x3;
-
-	for (i = 0; i < fls(crtcs); i++) {
+	for_each_set_bit(i, &disp->disp->head_mask, sizeof(disp->disp->head_mask) * 8) {
 		struct nv50_head *head;
 
-		if (!(crtcs & (1 << i)))
-			continue;
-
 		head = nv50_head_create(dev, i);
 		if (IS_ERR(head)) {
 			ret = PTR_ERR(head);
@@ -2814,7 +2802,7 @@ nv50_display_create(struct drm_device *dev)
 			 * Once these issues are closed, this should be
 			 * removed
 			 */
-			head->msto->encoder.possible_crtcs = crtcs;
+			head->msto->encoder.possible_crtcs = disp->disp->head_mask;
 		}
 	}