|
|
@@ -1,86 +0,0 @@
|
|
|
-#
|
|
|
-# Copyright (C) 2015 Google, Inc
|
|
|
-#
|
|
|
-# SPDX-License-Identifier: GPL-2.0+
|
|
|
-#
|
|
|
-
|
|
|
-EFI on U-Boot
|
|
|
-=============
|
|
|
-This document provides information about the implementation of the UEFI API [1]
|
|
|
-in U-Boot.
|
|
|
-
|
|
|
-
|
|
|
-=========== Table of Contents ===========
|
|
|
-
|
|
|
-Motivation
|
|
|
-How do I get it?
|
|
|
-Status
|
|
|
-Future work
|
|
|
-
|
|
|
-
|
|
|
-Motivation
|
|
|
-----------
|
|
|
-
|
|
|
-With this API support in place, you can run any UEFI payload (such as the Linux
|
|
|
-kernel, grub2 or gummiboot) on U-Boot. This dramatically simplifies boot loader
|
|
|
-configuration, as U-Boot based systems now look and feel (almost) the same way
|
|
|
-as TianoCore based systems.
|
|
|
-
|
|
|
-How do I get it?
|
|
|
-----------------
|
|
|
-
|
|
|
-EFI support for 32bit ARM and AArch64 is already included in U-Boot. All you
|
|
|
-need to do is enable
|
|
|
-
|
|
|
- CONFIG_CMD_BOOTEFI=y
|
|
|
- CONFIG_EFI_LOADER=y
|
|
|
-
|
|
|
-in your .config file and you will automatically get a bootefi command to run
|
|
|
-an efi application as well as snippet in the default distro boot script that
|
|
|
-scans for removable media efi binaries as fallback.
|
|
|
-
|
|
|
-Status
|
|
|
-------
|
|
|
-
|
|
|
-I am successfully able to run grub2 and Linux EFI binaries with this code on
|
|
|
-ARMv7 as well as AArch64 systems.
|
|
|
-
|
|
|
-When enabled, the resulting U-Boot binary only grows by ~10KB, so it's very
|
|
|
-light weight.
|
|
|
-
|
|
|
-All storage devices are directly accessible from the uEFI payload
|
|
|
-
|
|
|
-Removable media booting (search for /efi/boot/boota{a64,arm}.efi) is supported.
|
|
|
-
|
|
|
-Simple use cases like "Plug this SD card into my ARM device and it just
|
|
|
-boots into grub which boots into Linux", work very well.
|
|
|
-
|
|
|
-
|
|
|
-Running HelloWord.efi
|
|
|
----------------------
|
|
|
-
|
|
|
-You can run a simple 'hello world' EFI program in U-Boot.
|
|
|
-Enable the option CONFIG_CMD_BOOTEFI_HELLO.
|
|
|
-
|
|
|
-Then you can boot into U-Boot and type:
|
|
|
-
|
|
|
- > bootefi hello
|
|
|
-
|
|
|
-The 'hello world EFI' program will then run, print a message and exit.
|
|
|
-
|
|
|
-
|
|
|
-Future work
|
|
|
------------
|
|
|
-
|
|
|
-Of course, there are still a few things one could do on top:
|
|
|
-
|
|
|
- - Improve disk media detection (don't scan, use what information we
|
|
|
-have)
|
|
|
- - Add EFI variable support using NVRAM
|
|
|
- - Add GFX support
|
|
|
- - Make EFI Shell work
|
|
|
- - Network device support
|
|
|
- - Support for payload exit
|
|
|
- - Payload Watchdog support
|
|
|
-
|
|
|
-[1] http://uefi.org/
|
Heinrich Schuchardt