expo: Add support for scenes

A scene is a single screen within an expo. It is possible to move between
scenes but only one can be displayed at once.

Add a basic implementation.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 123 insertions, 0 deletions

diff --git a/boot/scene_internal.h b/boot/scene_internal.h
new file mode 100644
index 0000000000..e8fd765811
--- /dev/null
+++ b/boot/scene_internal.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Internal header file for scenes
+ *
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __SCENE_INTERNAL_H
+#define __SCENE_INTERNAL_H
+
+/**
+ * expo_lookup_scene_id() - Look up a scene ID
+ *
+ * @exp: Expo to use
+ * @id: scene ID to look up
+ * Returns: Scene for that ID, or NULL if none
+ */
+struct scene *expo_lookup_scene_id(struct expo *exp, uint scene_id);
+
+/**
+ * resolve_id() - Automatically allocate an ID if needed
+ *
+ * @exp: Expo to use
+ * @id: ID to use, or 0 to auto-allocate one
+ * @return: Either @id, or the auto-allocated ID
+ */
+uint resolve_id(struct expo *exp, uint id);
+
+/**
+ * scene_obj_find() - Find an object in a scene
+ *
+ * Note that @type is used to restrict the search when the object type is known.
+ * If any type is acceptable, set @type to SCENEOBJT_NONE
+ *
+ * @scn: Scene to search
+ * @id: ID of object to find
+ * @type: Type of the object, or SCENEOBJT_NONE to match any type
+ */
+void *scene_obj_find(struct scene *scn, uint id, enum scene_obj_t type);
+
+/**
+ * scene_obj_add() - Add a new object to a scene
+ *
+ * @scn: Scene to update
+ * @name: Name to use (this is allocated by this call)
+ * @id: ID to use for the new object (0 to allocate one)
+ * @type: Type of object to add
+ * @size: Size to allocate for the object, in bytes
+ * @objp: Returns a pointer to the new object (must not be NULL)
+ * Returns: ID number for the object (generally @id), or -ve on error
+ */
+int scene_obj_add(struct scene *scn, const char *name, uint id,
+		  enum scene_obj_t type, uint size, struct scene_obj **objp);
+
+/**
+ * scene_menu_arrange() - Set the position of things in the menu
+ *
+ * This updates any items associated with a menu to make sure they are
+ * positioned correctly relative to the menu. It also selects the first item
+ * if not already done
+ *
+ * @scn: Scene to update
+ * @menu: Menu to process
+ */
+int scene_menu_arrange(struct scene *scn, struct scene_obj_menu *menu);
+
+/**
+ * scene_menu_send_key() - Send a key to a menu for processing
+ *
+ * @scn: Scene to use
+ * @menu: Menu to use
+ * @key: Key code to send (KEY_...)
+ * @event: Place to put any event which is generated by the key
+ * @return 0 if OK, -ENOTTY if there is no current menu item, other -ve on other
+ *	error
+ */
+int scene_menu_send_key(struct scene *scn, struct scene_obj_menu *menu, int key,
+			struct expo_action *event);
+
+/**
+ * scene_menu_destroy() - Destroy a menu in a scene
+ *
+ * @scn: Scene to destroy
+ */
+void scene_menu_destroy(struct scene_obj_menu *menu);
+
+/**
+ * scene_menu_display() - Display a menu as text
+ *
+ * @menu: Menu to display
+ * @return 0 if OK, -ENOENT if @id is invalid
+ */
+int scene_menu_display(struct scene_obj_menu *menu);
+
+/**
+ * scene_destroy() - Destroy a scene and all its memory
+ *
+ * @scn: Scene to destroy
+ */
+void scene_destroy(struct scene *scn);
+
+/**
+ * scene_render() - Render a scene
+ *
+ * This is called from expo_render()
+ *
+ * @scn: Scene to render
+ * Returns: 0 if OK, -ve on error
+ */
+int scene_render(struct scene *scn);
+
+/**
+ * scene_send_key() - set a keypress to a scene
+ *
+ * @scn: Scene to receive the key
+ * @key: Key to send (KEYCODE_UP)
+ * @event: Returns resulting event from this keypress
+ * Returns: 0 if OK, -ve on error
+ */
+int scene_send_key(struct scene *scn, int key, struct expo_action *event);
+
+#endif /* __SCENE_INTERNAL_H */