expo: Add basic implementation

An expo is a way of presenting and collecting information from the
user. It consists of a collection of 'scenes' of which only one is
presented at a time. An expo is typically used to show a boot menu
and allow settings to be changed.

One created, the same expo can be automatically presented in graphical
form using a vidconsole, or in text form on a serial console.

Add an initial implementation of the expo itself. Supports for scenes
and objects is provided later.

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

2 files changed, 182 insertions, 0 deletions

diff --git a/boot/Kconfig b/boot/Kconfig
index 30bc182fcd..36ccbf6b54 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -557,6 +557,18 @@ config VPL_BOOTMETH_VBE_SIMPLE_FW
 
 endif # BOOTMETH_VBE
 
+config EXPO
+	bool "Support for expos - groups of scenes displaying a UI"
+	default y if BOOTMETH_VBE
+	help
+	  An expo is a way of presenting and collecting information from the
+	  user. It consists of a collection of 'scenes' of which only one is
+	  presented at a time. An expo is typically used to show a boot menu
+	  and allow settings to be changed.
+
+	  The expo can be presented in graphics form using a vidconsole, or in
+	  text form on a serial console.
+
 config BOOTMETH_SANDBOX
 	def_bool y
 	depends on SANDBOX
diff --git a/boot/expo.c b/boot/expo.c
new file mode 100644
index 0000000000..05950a1760
--- /dev/null
+++ b/boot/expo.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Implementation of a expo, a collection of scenes providing menu options
+ *
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <expo.h>
+#include <malloc.h>
+#include <video.h>
+#include "scene_internal.h"
+
+int expo_new(const char *name, void *priv, struct expo **expp)
+{
+	struct expo *exp;
+
+	exp = calloc(1, sizeof(struct expo));
+	if (!exp)
+		return log_msg_ret("expo", -ENOMEM);
+	exp->name = strdup(name);
+	if (!exp->name) {
+		free(exp);
+		return log_msg_ret("name", -ENOMEM);
+	}
+	exp->priv = priv;
+	INIT_LIST_HEAD(&exp->scene_head);
+	INIT_LIST_HEAD(&exp->str_head);
+
+	*expp = exp;
+
+	return 0;
+}
+
+static void estr_destroy(struct expo_string *estr)
+{
+	free(estr);
+}
+
+void expo_destroy(struct expo *exp)
+{
+	struct scene *scn, *next;
+	struct expo_string *estr, *enext;
+
+	list_for_each_entry_safe(scn, next, &exp->scene_head, sibling)
+		scene_destroy(scn);
+
+	list_for_each_entry_safe(estr, enext, &exp->str_head, sibling)
+		estr_destroy(estr);
+
+	free(exp->name);
+	free(exp);
+}
+
+int expo_str(struct expo *exp, const char *name, uint id, const char *str)
+{
+	struct expo_string *estr;
+
+	estr = calloc(1, sizeof(struct expo_string));
+	if (!estr)
+		return log_msg_ret("obj", -ENOMEM);
+
+	estr->id = resolve_id(exp, id);
+	estr->str = str;
+	list_add_tail(&estr->sibling, &exp->str_head);
+
+	return estr->id;
+}
+
+const char *expo_get_str(struct expo *exp, uint id)
+{
+	struct expo_string *estr;
+
+	list_for_each_entry(estr, &exp->str_head, sibling) {
+		if (estr->id == id)
+			return estr->str;
+	}
+
+	return NULL;
+}
+
+int expo_set_display(struct expo *exp, struct udevice *dev)
+{
+	exp->display = dev;
+
+	return 0;
+}
+
+void exp_set_text_mode(struct expo *exp, bool text_mode)
+{
+	exp->text_mode = text_mode;
+}
+
+struct scene *expo_lookup_scene_id(struct expo *exp, uint scene_id)
+{
+	struct scene *scn;
+
+	list_for_each_entry(scn, &exp->scene_head, sibling) {
+		if (scn->id == scene_id)
+			return scn;
+	}
+
+	return NULL;
+}
+
+int expo_set_scene_id(struct expo *exp, uint scene_id)
+{
+	if (!expo_lookup_scene_id(exp, scene_id))
+		return log_msg_ret("id", -ENOENT);
+	exp->scene_id = scene_id;
+
+	return 0;
+}
+
+int expo_render(struct expo *exp)
+{
+	struct udevice *dev = exp->display;
+	struct video_priv *vid_priv = dev_get_uclass_priv(dev);
+	struct scene *scn = NULL;
+	u32 colour;
+	int ret;
+
+	colour = video_index_to_colour(vid_priv, VID_WHITE);
+	ret = video_fill(dev, colour);
+	if (ret)
+		return log_msg_ret("fill", ret);
+
+	if (exp->scene_id) {
+		scn = expo_lookup_scene_id(exp, exp->scene_id);
+		if (!scn)
+			return log_msg_ret("scn", -ENOENT);
+
+		ret = scene_render(scn);
+		if (ret)
+			return log_msg_ret("ren", ret);
+	}
+
+	video_sync(dev, true);
+
+	return scn ? 0 : -ECHILD;
+}
+
+int expo_send_key(struct expo *exp, int key)
+{
+	struct scene *scn = NULL;
+
+	if (exp->scene_id) {
+		int ret;
+
+		scn = expo_lookup_scene_id(exp, exp->scene_id);
+		if (!scn)
+			return log_msg_ret("scn", -ENOENT);
+
+		ret = scene_send_key(scn, key, &exp->action);
+		if (ret)
+			return log_msg_ret("key", ret);
+	}
+
+	return scn ? 0 : -ECHILD;
+}
+
+int expo_action_get(struct expo *exp, struct expo_action *act)
+{
+	*act = exp->action;
+	exp->action.type = EXPOACT_NONE;
+
+	return act->type == EXPOACT_NONE ? -EAGAIN : 0;
+}