drm/tegra: dc: Dedicate overlay plane to cursor on older Tegra's

Older Tegra's do not support RGBA format for the cursor, but instead
overlay plane could be used for it. Since there is no much use for the
overlays on a regular desktop and HW-accelerated cursor is much better
than a SW cursor, let's dedicate one overlay plane to the mouse cursor.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dc.c

@@ -864,11 +864,13 @@ static const u32 tegra124_overlay_formats[] = {
 
 static struct drm_plane *tegra_dc_overlay_plane_create(struct drm_device *drm,
 						       struct tegra_dc *dc,
-						       unsigned int index)
+						       unsigned int index,
+						       bool cursor)
 {
 	unsigned long possible_crtcs = tegra_plane_get_possible_crtcs(drm);
 	struct tegra_plane *plane;
 	unsigned int num_formats;
+	enum drm_plane_type type;
 	const u32 *formats;
 	int err;
 
@@ -883,10 +885,14 @@ static struct drm_plane *tegra_dc_overlay_plane_create(struct drm_device *drm,
 	num_formats = dc->soc->num_overlay_formats;
 	formats = dc->soc->overlay_formats;
 
+	if (!cursor)
+		type = DRM_PLANE_TYPE_OVERLAY;
+	else
+		type = DRM_PLANE_TYPE_CURSOR;
+
 	err = drm_universal_plane_init(drm, &plane->base, possible_crtcs,
 				       &tegra_plane_funcs, formats,
-				       num_formats, NULL,
-				       DRM_PLANE_TYPE_OVERLAY, NULL);
+				       num_formats, NULL, type, NULL);
 	if (err < 0) {
 		kfree(plane);
 		return ERR_PTR(err);
@@ -938,15 +944,22 @@ static struct drm_plane *tegra_dc_add_planes(struct drm_device *drm,
 					     struct tegra_dc *dc)
 {
 	struct drm_plane *planes[2], *primary;
+	unsigned int planes_num;
 	unsigned int i;
 	int err;
 
 	primary = tegra_primary_plane_create(drm, dc);
 	if (IS_ERR(primary))
 		return primary;
 
-	for (i = 0; i < 2; i++) {
-		planes[i] = tegra_dc_overlay_plane_create(drm, dc, 1 + i);
+	if (dc->soc->supports_cursor)
+		planes_num = 2;
+	else
+		planes_num = 1;
+
+	for (i = 0; i < planes_num; i++) {
+		planes[i] = tegra_dc_overlay_plane_create(drm, dc, 1 + i,
+							  false);
 		if (IS_ERR(planes[i])) {
 			err = PTR_ERR(planes[i]);
 
@@ -1864,6 +1877,13 @@ static int tegra_dc_init(struct host1x_client *client)
 			err = PTR_ERR(cursor);
 			goto cleanup;
 		}
+	} else {
+		/* dedicate one overlay to mouse cursor */
+		cursor = tegra_dc_overlay_plane_create(drm, dc, 2, true);
+		if (IS_ERR(cursor)) {
+			err = PTR_ERR(cursor);
+			goto cleanup;
+		}
 	}
 
 	err = drm_crtc_init_with_planes(drm, &dc->base, primary, cursor,