rk3399_rockchip-uboot/doc/README.efi

9   1  U-Boot on EFI
15   1.6  EFI Application
16   1.7  EFI Payload
23   2  EFI on U-Boot
29 U-Boot on EFI
31 This document provides information about U-Boot running on top of EFI, either
39 - You have EFI running on a board but U-Boot does not natively support it
40 fully yet. You can boot into U-Boot from EFI and use that until U-Boot is
43 - You need to use an EFI implementation (e.g. UEFI) because your vendor
48 on EFI and then move to U-Boot on coreboot when ready
50 - You use EFI but want to experiment with a simpler alternative like U-Boot
55 Only x86 is supported at present. If you are using EFI on another architecture
59 U-Boot supports running as an EFI application for 32-bit EFI only. This is
64 or 64-bit EFI. U-Boot is packaged up and loaded in its entirety by EFI. Once
71 First choose a board that has EFI support and obtain an EFI implementation
75 To build U-Boot as an EFI application (32-bit EFI required), enable CONFIG_EFI
76 and CONFIG_EFI_APP. The efi-x86 config (efi-x86_defconfig) is set up for this.
79    make efi-x86_defconfig
82 To build U-Boot as an EFI payload (32-bit or 64-bit EFI can be used), adjust an
92    u-boot-app.efi      - U-Boot EFI application
93    u-boot-payload.efi  - U-Boot EFI payload application
102    mkdir /tmp/efi
103    cp /path/to/u-boot*.efi /tmp/efi
104    qemu-system-x86_64 -bios bios.bin -hda fat:/tmp/efi/
107 type 'fs0:u-boot-payload.efi' to run the payload or 'fs0:u-boot-app.efi' to
108 run the application. 'bios.bin' is the EFI 'BIOS'. Check [2] to obtain a
109 prebuilt EFI BIOS for QEMU or you can build one from source as well.
111 To try it on real hardware, put u-boot-app.efi on a suitable boot medium,
114    fs0:u-boot-payload.efi
116 (or fs0:u-boot-app.efi for the application)
119 that EFI does not support booting a 64-bit application from a 32-bit
120 EFI (or vice versa). Also it will often fail to print an error message if
132 EFI Application
135 efi_main() function is in lib/efi/efi_app.c. It sets up some basic EFI
143 The CONFIG_EFI option controls more general EFI adjustments.
145 The only available driver is the serial driver. This calls back into EFI
148 boot EFI with video output then the 'serial' device will operate on your
152 These are features of EFI, not U-Boot.
154 Very little code is involved in implementing the EFI application feature.
158 arch/x86/cpu. Porting to ARM (which can also use EFI if you are brave
161 Use the 'reset' command to get back to EFI.
163 EFI Payload
167 image (including device tree) into a small EFI stub application responsible
168 for booting it. The stub application is built as a normal EFI application
171 The stub application is implemented in lib/efi/efi_stub.c. The efi_main()
172 function is called by EFI. It is responsible for copying U-Boot from its
173 original location into memory, disabling EFI boot services and starting
179 While the stub application does allocate some memory from EFI this is not
186 The payload can pass information to U-Boot in the form of EFI tables. At
187 present this feature is used to pass the EFI memory map, an inordinately
188 large list of memory regions. You can use the 'efi mem all' command to
192 Although U-Boot can use any memory it likes, EFI marks some memory as used
196 fan speed. U-Boot uses only 'conventional' memory, in EFI terminology. It
202 U-Boot drivers typically don't use interrupts. Since EFI enables interrupts
209 While the EFI application can in principle be built as either 32- or 64-bit,
211 be used with 32-bit EFI.
214 of code is built this way (see the extra- line in lib/efi/Makefile).
222 - Add a generic x86 EFI payload configuration. At present you need to modify
224 on EFI anyway, so a generic 'EFI' board could be created with a suitable set
243 lib/efi
246 arch/x86/lib/efi
250 arch/x86/cpu/efi
251 	x86 support code for running as an EFI application
253 board/efi/efi-x86/efi.c
254 	x86 board code for running as an EFI application
257 	the 'efi' command
269 EFI on U-Boot
287 EFI support for 32bit ARM and AArch64 is already included in U-Boot. All you
294 an efi application as well as snippet in the default distro boot script that
295 scans for removable media efi binaries as fallback.
300 I am successfully able to run grub2 and Linux EFI binaries with this code on
308 Removable media booting (search for /efi/boot/boota{a64,arm}.efi) is supported.
314 Running HelloWord.efi
317 You can run a simple 'hello world' EFI program in U-Boot.
324 The 'hello world EFI' program will then run, print a message and exit.
334    - Add EFI variable support using NVRAM
336    - Make EFI Shell work