efi: Add support for loading U-Boot through an EFI stub

It is useful to be able to load U-Boot onto a board even if is it already
running EFI. This can allow access to the U-Boot command interface, flexible
booting options and easier development.

The easiest way to do this is to build U-Boot as a binary blob and have an
EFI stub copy it into RAM. Add support for this feature, targeting 32-bit
initially.

Also add a way to detect when U-Boot has been loaded via a stub. This goes
in common.h since it needs to be widely available so that we avoid redoing
initialisation that should be skipped.

Signed-off-by: Simon Glass <sjg@chromium.org>
Improvements to how the payload is built:
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Simon Glass
2015-08-04 12:33:52 -06:00
parent 465a67cf52
commit 476476e73b
7 changed files with 376 additions and 0 deletions

View File

@ -755,6 +755,7 @@ ALL-$(CONFIG_SPL) += $(CONFIG_SPL_TARGET:"%"=%)
endif
ALL-$(CONFIG_REMAKE_ELF) += u-boot.elf
ALL-$(CONFIG_EFI_APP) += u-boot-app.efi
ALL-$(CONFIG_EFI_STUB) += u-boot-payload.efi
ifneq ($(BUILD_ROM),)
ALL-$(CONFIG_X86_RESET_VECTOR) += u-boot.rom
@ -790,6 +791,9 @@ cmd_objcopy = $(OBJCOPY) --gap-fill=0xff $(OBJCOPYFLAGS) \
quiet_cmd_zobjcopy = OBJCOPY $@
cmd_zobjcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
quiet_cmd_efipayload = OBJCOPY $@
cmd_efipayload = $(OBJCOPY) -I binary -O $(EFIPAYLOAD_BFDTARGET) -B $(EFIPAYLOAD_BFDARCH) $< $@
quiet_cmd_mkimage = MKIMAGE $@
cmd_mkimage = $(objtree)/tools/mkimage $(MKIMAGEFLAGS_$(@F)) -d $< $@ \
$(if $(KBUILD_VERBOSE:1=), >/dev/null)
@ -1087,6 +1091,26 @@ OBJCOPYFLAGS_u-boot-app.efi := $(OBJCOPYFLAGS_EFI)
u-boot-app.efi: u-boot FORCE
$(call if_changed,zobjcopy)
u-boot-dtb.bin.o: u-boot-dtb.bin FORCE
$(call if_changed,efipayload)
u-boot-payload.lds: $(LDSCRIPT_EFI) FORCE
$(call if_changed_dep,cpp_lds)
# Rule to link the EFI payload which contains a stub and a U-Boot binary
quiet_cmd_u-boot_payload ?= LD $@
cmd_u-boot_payload ?= $(LD) $(LDFLAGS_EFI_PAYLOAD) -o $@ \
-T u-boot-payload.lds \
lib/efi/efi.o lib/efi/efi_stub.o u-boot-dtb.bin.o \
$(addprefix arch/$(ARCH)/lib/efi/,$(EFISTUB))
u-boot-payload: u-boot-dtb.bin.o u-boot-payload.lds FORCE
$(call if_changed,u-boot_payload)
OBJCOPYFLAGS_u-boot-payload.efi := $(OBJCOPYFLAGS_EFI)
u-boot-payload.efi: u-boot-payload FORCE
$(call if_changed,zobjcopy)
u-boot-img.bin: spl/u-boot-spl.bin u-boot.img FORCE
$(call if_changed,cat)