drm/ast: Add cursor-plane data structure

Cursor state is currently located throughout struct ast_private. Having
struct ast_cursor_plane as dedicated data structure for cursors helps to
organize the modesetting code.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210209134632.12157-7-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_drv.h

@@ -81,6 +81,9 @@ enum ast_tx_chip {
 #define AST_DRAM_4Gx16   7
 #define AST_DRAM_8Gx16   8
 
+/*
+ * Cursor plane
+ */
 
 #define AST_MAX_HWC_WIDTH	64
 #define AST_MAX_HWC_HEIGHT	64
@@ -99,6 +102,20 @@ enum ast_tx_chip {
 #define AST_HWC_SIGNATURE_HOTSPOTX	0x14
 #define AST_HWC_SIGNATURE_HOTSPOTY	0x18
 
+struct ast_cursor_plane {
+	struct drm_plane base;
+};
+
+static inline struct ast_cursor_plane *
+to_ast_cursor_plane(struct drm_plane *plane)
+{
+	return container_of(plane, struct ast_cursor_plane, base);
+}
+
+/*
+ * Connector with i2c channel
+ */
+
 struct ast_i2c_chan {
 	struct i2c_adapter adapter;
 	struct drm_device *dev;
@@ -116,6 +133,10 @@ to_ast_connector(struct drm_connector *connector)
 	return container_of(connector, struct ast_connector, base);
 }
 
+/*
+ * Device
+ */
+
 struct ast_private {
 	struct drm_device base;
 
@@ -136,7 +157,7 @@ struct ast_private {
 	} cursor;
 
 	struct drm_plane primary_plane;
-	struct drm_plane cursor_plane;
+	struct ast_cursor_plane cursor_plane;
 	struct drm_crtc crtc;
 	struct drm_encoder encoder;
 	struct ast_connector connector;

drivers/gpu/drm/ast/ast_mode.c

@@ -932,7 +932,8 @@ static const struct drm_plane_funcs ast_cursor_plane_funcs = {
 static int ast_cursor_plane_init(struct ast_private *ast)
 {
 	struct drm_device *dev = &ast->base;
-	struct drm_plane *cursor_plane = &ast->cursor_plane;
+	struct ast_cursor_plane *ast_cursor_plane = &ast->cursor_plane;
+	struct drm_plane *cursor_plane = &ast_cursor_plane->base;
 	size_t size, i;
 	struct drm_gem_vram_object *gbo;
 	int ret;
@@ -1178,7 +1179,7 @@ static int ast_crtc_init(struct drm_device *dev)
 	int ret;
 
 	ret = drm_crtc_init_with_planes(dev, crtc, &ast->primary_plane,
-					&ast->cursor_plane, &ast_crtc_funcs,
+					&ast->cursor_plane.base, &ast_crtc_funcs,
 					NULL);
 	if (ret)
 		return ret;