xref: /openbmc/u-boot/doc/README.menu (revision 977a39e6)
1/*
2 * Copyright 2010-2011 Calxeda, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the Free
6 * Software Foundation; either version 2 of the License, or (at your option)
7 * any later version.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program.  If not, see <http://www.gnu.org/licenses/>.
16 */
17
18U-boot provides a set of interfaces for creating and using simple, text
19based menus. Menus are displayed as lists of labeled entries on the
20console, and an entry can be selected by entering its label.
21
22To use the menu code, enable CONFIG_MENU, and include "menu.h" where
23the interfaces should be available.
24
25Menus are composed of items. Each item has a key used to identify it in
26the menu, and an opaque pointer to data controlled by the consumer.
27
28Interfaces
29----------
30#include "menu.h"
31
32/*
33 * Consumers of the menu interfaces will use a struct menu * as the
34 * handle for a menu. struct menu is only fully defined in menu.c,
35 * preventing consumers of the menu interfaces from accessing its
36 * contents directly.
37 */
38struct menu;
39
40/*
41 * NOTE: See comments in common/menu.c for more detailed documentation on
42 * these interfaces.
43 */
44
45/*
46 * menu_create() - Creates a menu handle with default settings
47 */
48struct menu *menu_create(char *title, int timeout, int prompt,
49				void (*item_data_print)(void *));
50
51/*
52 * menu_item_add() - Adds or replaces a menu item
53 */
54int menu_item_add(struct menu *m, char *item_key, void *item_data);
55
56/*
57 * menu_default_set() - Sets the default choice for the menu
58 */
59int menu_default_set(struct menu *m, char *item_key);
60
61/*
62 * menu_get_choice() - Returns the user's selected menu entry, or the
63 * default if the menu is set to not prompt or the timeout expires.
64 */
65int menu_get_choice(struct menu *m, void **choice);
66
67/*
68 * menu_destroy() - frees the memory used by a menu and its items.
69 */
70int menu_destroy(struct menu *m);
71
72
73Example Code
74------------
75This example creates a menu that always prompts, and allows the user
76to pick from a list of tools.  The item key and data are the same.
77
78#include "menu.h"
79
80char *tools[] = {
81	"Hammer",
82	"Screwdriver",
83	"Nail gun",
84	NULL
85};
86
87char *pick_a_tool(void)
88{
89	struct menu *m;
90	int i;
91	char *tool = NULL;
92
93	m = menu_create("Tools", 0, 1, NULL);
94
95	for(i = 0; tools[i]; i++) {
96		if (menu_item_add(m, tools[i], tools[i]) != 1) {
97			printf("failed to add item!");
98			menu_destroy(m);
99			return NULL;
100		}
101	}
102
103	if (menu_get_choice(m, (void **)&tool) != 1)
104		printf("Problem picking tool!\n");
105
106	menu_destroy(m);
107
108	return tool;
109}
110
111void caller(void)
112{
113	char *tool = pick_a_tool();
114
115	if (tool) {
116		printf("picked a tool: %s\n", tool);
117		use_tool(tool);
118	}
119}
120