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diff --git a/roms/u-boot/doc/develop/menus.rst b/roms/u-boot/doc/develop/menus.rst new file mode 100644 index 000000000..dda8f963f --- /dev/null +++ b/roms/u-boot/doc/develop/menus.rst @@ -0,0 +1,131 @@ +.. SPDX-License-Identifier: GPL-2.0+ +.. Copyright 2010-2011 Calxeda, Inc. + +Menus +===== + +U-Boot provides a set of interfaces for creating and using simple, text +based menus. Menus are displayed as lists of labeled entries on the +console, and an entry can be selected by entering its label. + +To use the menu code, enable CONFIG_MENU, and include "menu.h" where +the interfaces should be available. + +Menus are composed of items. Each item has a key used to identify it in +the menu, and an opaque pointer to data controlled by the consumer. + +If you want to show a menu, instead starting the shell, define +CONFIG_AUTOBOOT_MENU_SHOW. You have to code the int menu_show(int bootdelay) +function, which handle your menu. This function returns the remaining +bootdelay. + +Interfaces +---------- + +.. code-block:: c + + #include "menu.h" + + /* + * Consumers of the menu interfaces will use a struct menu * as the + * handle for a menu. struct menu is only fully defined in menu.c, + * preventing consumers of the menu interfaces from accessing its + * contents directly. + */ + struct menu; + + /* + * NOTE: See comments in common/menu.c for more detailed documentation on + * these interfaces. + */ + + /* + * menu_create() - Creates a menu handle with default settings + */ + struct menu *menu_create(char *title, int timeout, int prompt, + void (*item_data_print)(void *), + char *(*item_choice)(void *), + void *item_choice_data); + + /* + * menu_item_add() - Adds or replaces a menu item + */ + int menu_item_add(struct menu *m, char *item_key, void *item_data); + + /* + * menu_default_set() - Sets the default choice for the menu + */ + int menu_default_set(struct menu *m, char *item_key); + + /* + * menu_default_choice() - Set *choice to point to the default item's data + */ + int menu_default_choice(struct menu *m, void **choice); + + /* + * menu_get_choice() - Returns the user's selected menu entry, or the + * default if the menu is set to not prompt or the timeout expires. + */ + int menu_get_choice(struct menu *m, void **choice); + + /* + * menu_destroy() - frees the memory used by a menu and its items. + */ + int menu_destroy(struct menu *m); + + /* + * menu_display_statusline(struct menu *m); + * shows a statusline for every menu_display call. + */ + void menu_display_statusline(struct menu *m); + +Example Code +------------ + +This example creates a menu that always prompts, and allows the user +to pick from a list of tools. The item key and data are the same. + +.. code-block:: c + + #include "menu.h" + + char *tools[] = { + "Hammer", + "Screwdriver", + "Nail gun", + NULL + }; + + char *pick_a_tool(void) + { + struct menu *m; + int i; + char *tool = NULL; + + m = menu_create("Tools", 0, 1, NULL); + + for(i = 0; tools[i]; i++) { + if (menu_item_add(m, tools[i], tools[i]) != 1) { + printf("failed to add item!"); + menu_destroy(m); + return NULL; + } + } + + if (menu_get_choice(m, (void **)&tool) != 1) + printf("Problem picking tool!\n"); + + menu_destroy(m); + + return tool; + } + + void caller(void) + { + char *tool = pick_a_tool(); + + if (tool) { + printf("picked a tool: %s\n", tool); + use_tool(tool); + } + } |