expo: Begin implementation of a text editor

It is useful to be able to edit text, e.g. to allow the user to edit the
environment or the command-line arguments for the OS.

Add the beginnings of an implementation. Future work is needed to finish
this: keypress handling and scrolling. For now it just displays the
text.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/Makefile b/boot/Makefile
index 71dafae..e0d1579 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -58,7 +58,7 @@
 obj-$(CONFIG_$(PHASE_)LOAD_FIT) += common_fit.o
 
 obj-$(CONFIG_$(PHASE_)EXPO) += expo.o scene.o expo_build.o
-obj-$(CONFIG_$(PHASE_)EXPO) += scene_menu.o scene_textline.o
+obj-$(CONFIG_$(PHASE_)EXPO) += scene_menu.o scene_textline.o scene_textedit.o
 ifdef CONFIG_COREBOOT_SYSINFO
 obj-$(CONFIG_$(PHASE_)EXPO) += expo_build_cb.o
 endif
diff --git a/boot/cedit.c b/boot/cedit.c
index 9153fe7..5481025 100644
--- a/boot/cedit.c
+++ b/boot/cedit.c
@@ -82,6 +82,7 @@
 		case SCENEOBJT_IMAGE:
 		case SCENEOBJT_TEXT:
 		case SCENEOBJT_BOX:
+		case SCENEOBJT_TEXTEDIT:
 			break;
 		case SCENEOBJT_MENU:
 			scene_obj_set_pos(scn, obj->id, 50, y);
@@ -383,6 +384,7 @@
 	case SCENEOBJT_IMAGE:
 	case SCENEOBJT_TEXT:
 	case SCENEOBJT_BOX:
+	case SCENEOBJT_TEXTEDIT:
 		break;
 	case SCENEOBJT_TEXTLINE: {
 		const struct scene_obj_textline *tline;
@@ -483,6 +485,7 @@
 	case SCENEOBJT_IMAGE:
 	case SCENEOBJT_TEXT:
 	case SCENEOBJT_BOX:
+	case SCENEOBJT_TEXTEDIT:
 		break;
 	case SCENEOBJT_TEXTLINE: {
 		const struct scene_obj_textline *tline;
@@ -555,6 +558,7 @@
 	case SCENEOBJT_IMAGE:
 	case SCENEOBJT_TEXT:
 	case SCENEOBJT_BOX:
+	case SCENEOBJT_TEXTEDIT:
 		break;
 	case SCENEOBJT_MENU:
 		menu = (struct scene_obj_menu *)obj;
@@ -639,6 +643,7 @@
 	case SCENEOBJT_IMAGE:
 	case SCENEOBJT_TEXT:
 	case SCENEOBJT_BOX:
+	case SCENEOBJT_TEXTEDIT:
 		break;
 	case SCENEOBJT_MENU:
 		menu = (struct scene_obj_menu *)obj;
diff --git a/boot/scene.c b/boot/scene.c
index 3091a9e..c8dc171 100644
--- a/boot/scene.c
+++ b/boot/scene.c
@@ -417,13 +417,19 @@
 			*widthp = width;
 		return height;
 	}
-	case SCENEOBJT_TEXT: {
-		struct scene_txt_generic *gen = &((struct scene_obj_txt *)obj)->gen;
+	case SCENEOBJT_TEXT:
+	case SCENEOBJT_TEXTEDIT: {
+		struct scene_txt_generic *gen;
 		struct expo *exp = scn->expo;
 		struct vidconsole_bbox bbox;
 		int len, ret, limit;
 		const char *str;
 
+		if (obj->type == SCENEOBJT_TEXT)
+			gen = &((struct scene_obj_txt *)obj)->gen;
+		else
+			gen = &((struct scene_obj_txtedit *)obj)->gen;
+
 		str = expo_get_str(exp, gen->str_id);
 		if (!str)
 			return log_msg_ret("str", -ENOENT);
@@ -658,6 +664,13 @@
 			       obj->bbox.y1, box->width, vid_priv->colour_fg);
 		break;
 	}
+	case SCENEOBJT_TEXTEDIT: {
+		struct scene_obj_txtedit *ted = (struct scene_obj_txtedit *)obj;
+
+		ret = scene_txt_render(exp, dev, cons, obj, &ted->gen, x, y,
+				       theme->menu_inset);
+		break;
+	}
 	}
 
 	return 0;
@@ -677,6 +690,7 @@
 		case SCENEOBJT_IMAGE:
 		case SCENEOBJT_TEXT:
 		case SCENEOBJT_BOX:
+		case SCENEOBJT_TEXTEDIT:
 			break;
 		case SCENEOBJT_MENU: {
 			struct scene_obj_menu *menu;
@@ -736,6 +750,7 @@
 		case SCENEOBJT_IMAGE:
 		case SCENEOBJT_TEXT:
 		case SCENEOBJT_BOX:
+		case SCENEOBJT_TEXTEDIT:
 			break;
 		case SCENEOBJT_MENU: {
 			struct scene_obj_menu *menu;
@@ -782,6 +797,7 @@
 		case SCENEOBJT_IMAGE:
 		case SCENEOBJT_TEXT:
 		case SCENEOBJT_BOX:
+		case SCENEOBJT_TEXTEDIT:
 			break;
 		case SCENEOBJT_MENU:
 			scene_menu_render_deps(scn,
@@ -921,6 +937,9 @@
 				return log_msg_ret("key", ret);
 			break;
 		}
+		case SCENEOBJT_TEXTEDIT:
+			/* TODO(sjg@chromium.org): Implement this */
+			break;
 		}
 		return 0;
 	}
@@ -947,6 +966,7 @@
 	case SCENEOBJT_IMAGE:
 	case SCENEOBJT_TEXT:
 	case SCENEOBJT_BOX:
+	case SCENEOBJT_TEXTEDIT:
 		return -ENOSYS;
 	case SCENEOBJT_MENU: {
 		struct scene_obj_menu *menu = (struct scene_obj_menu *)obj;
@@ -977,6 +997,7 @@
 		case SCENEOBJT_NONE:
 		case SCENEOBJT_TEXT:
 		case SCENEOBJT_BOX:
+		case SCENEOBJT_TEXTEDIT:
 		case SCENEOBJT_IMAGE: {
 			int width;
 
@@ -1038,6 +1059,10 @@
 		case SCENEOBJT_BOX:
 		case SCENEOBJT_TEXTLINE:
 			break;
+		case SCENEOBJT_TEXTEDIT:
+			scene_txted_set_font(scn, obj->id, NULL,
+					     theme->font_size);
+			break;
 		case SCENEOBJT_TEXT:
 			scene_txt_set_font(scn, obj->id, NULL,
 					   theme->font_size);
@@ -1079,6 +1104,7 @@
 	case SCENEOBJT_MENU:
 	case SCENEOBJT_TEXT:
 	case SCENEOBJT_BOX:
+	case SCENEOBJT_TEXTEDIT:
 		break;
 	case SCENEOBJT_TEXTLINE:
 		ret = scene_textline_open(scn,
diff --git a/boot/scene_internal.h b/boot/scene_internal.h
index ac2a36d..760cc62 100644
--- a/boot/scene_internal.h
+++ b/boot/scene_internal.h
@@ -414,4 +414,16 @@
  */
 int scene_calc_arrange(struct scene *scn, struct expo_arrange_info *arr);
 
+/**
+ * scene_txt_generic_init() - Set up the generic part of a text object
+ *
+ * @exp: Expo containing the object
+ * @gen: Generic text info
+ * @name: Object name
+ * @str_id: String ID for the text
+ * @str: Initial text string for the object, or NULL to just use str_id
+ */
+int scene_txt_generic_init(struct expo *exp, struct scene_txt_generic *gen,
+			   const char *name, uint str_id, const char *str);
+
 #endif /* __SCENE_INTERNAL_H */
diff --git a/boot/scene_textedit.c b/boot/scene_textedit.c
new file mode 100644
index 0000000..8242eb3
--- /dev/null
+++ b/boot/scene_textedit.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Implementation of a menu in a scene
+ *
+ * Copyright 2025 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY	LOGC_EXPO
+
+#include <expo.h>
+#include <log.h>
+#include <linux/err.h>
+#include <linux/sizes.h>
+#include "scene_internal.h"
+
+enum {
+	INITIAL_SIZE	= SZ_4K,
+};
+
+int scene_texted(struct scene *scn, const char *name, uint id, uint str_id,
+		 struct scene_obj_txtedit **teditp)
+{
+	struct scene_obj_txtedit *ted;
+	char *buf;
+	int ret;
+
+	ret = scene_obj_add(scn, name, id, SCENEOBJT_TEXTEDIT,
+			    sizeof(struct scene_obj_txtedit),
+			    (struct scene_obj **)&ted);
+	if (ret < 0)
+		return log_msg_ret("obj", ret);
+
+	abuf_init(&ted->buf);
+	if (!abuf_realloc(&ted->buf, INITIAL_SIZE))
+		return log_msg_ret("buf", -ENOMEM);
+	buf = abuf_data(&ted->buf);
+	*buf = '\0';
+
+	ret = scene_txt_generic_init(scn->expo, &ted->gen, name, str_id, buf);
+	if (ret)
+		return log_msg_ret("teg", ret);
+	if (teditp)
+		*teditp = ted;
+
+	return ted->obj.id;
+}
+
+int scene_txted_set_font(struct scene *scn, uint id, const char *font_name,
+			 uint font_size)
+{
+	struct scene_obj_txtedit *ted;
+
+	ted = scene_obj_find(scn, id, SCENEOBJT_TEXTEDIT);
+	if (!ted)
+		return log_msg_ret("find", -ENOENT);
+	ted->gen.font_name = font_name;
+	ted->gen.font_size = font_size;
+
+	return 0;
+}