[Buildroot] [PATCH v2] uboot: add support for bundling ATF BL31 in ELF format into U-Boot

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

Thanks for this contribution!

On Sun, 11 Nov 2018 17:45:32 +0100, Micha? ?yszczek wrote:

> diff --git a/boot/arm-trusted-firmware/arm-trusted-firmware.mk b/boot/arm-trusted-firmware/arm-trusted-firmware.mk
> index 23f493653d..8f0f745ac0 100644
> --- a/boot/arm-trusted-firmware/arm-trusted-firmware.mk
> +++ b/boot/arm-trusted-firmware/arm-trusted-firmware.mk
> @@ -94,6 +94,12 @@ ARM_TRUSTED_FIRMWARE_MAKE_OPTS += RESET_TO_BL31=1
>  ARM_TRUSTED_FIRMWARE_DEPENDENCIES += host-uboot-tools
>  endif
>  
> +ifeq ($(BR2_TARGET_UBOOT_NEEDS_ATF_BL31_ELF),y)
> +define ARM_TRUSTED_FIRMWARE_BL31_UBOOT_INSTALL_ELF
> +	cp -dpf $(ARM_TRUSTED_FIRMWARE_IMG_DIR)/bl31/bl31.elf $(BINARIES_DIR)/
> +endef
> +endif
> +
>  define ARM_TRUSTED_FIRMWARE_BUILD_CMDS
>  	$(ARM_TRUSTED_FIRMWARE_BUILD_FIPTOOL)
>  	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) $(ARM_TRUSTED_FIRMWARE_MAKE_OPTS) \
> @@ -104,6 +110,7 @@ endef
>  define ARM_TRUSTED_FIRMWARE_INSTALL_IMAGES_CMDS
>  	cp -dpf $(ARM_TRUSTED_FIRMWARE_IMG_DIR)/*.bin $(BINARIES_DIR)/
>  	$(ARM_TRUSTED_FIRMWARE_BL31_UBOOT_INSTALL)
> +	$(ARM_TRUSTED_FIRMWARE_BL31_UBOOT_INSTALL_ELF)
>  endef
>  
>  # Configuration check
> diff --git a/boot/uboot/Config.in b/boot/uboot/Config.in
> index ac6f8bc8c1..7f2f7945ac 100644
> --- a/boot/uboot/Config.in
> +++ b/boot/uboot/Config.in
> @@ -179,6 +179,13 @@ config BR2_TARGET_UBOOT_NEEDS_ATF_BL31
>  	  variable pointing to ATF's BL31 binary, is passed during the
>  	  Buildroot build.
>  
> +config BR2_TARGET_UBOOT_NEEDS_ATF_BL31_ELF
> +	bool "U-Boot needs bl31.elf"
> +	depends on BR2_TARGET_UBOOT_NEEDS_ATF_BL31
> +	help
> +		Uses bl31.elf instead of bl31.bin image.  This is needed by some
> +		platforms (like rk3328) to generate valid uboot.itb with ATF

Nit: the indentation for the help text should be one tab + two spaces.

>  ifeq ($(BR2_TARGET_UBOOT_NEEDS_ATF_BL31),y)
>  UBOOT_DEPENDENCIES += arm-trusted-firmware
> +ifeq ($(BR2_TARGET_UBOOT_NEEDS_ATF_BL31_ELF),y)
> +UBOOT_MAKE_OPTS += BL31=$(BINARIES_DIR)/bl31.elf
> +else
>  UBOOT_MAKE_OPTS += BL31=$(BINARIES_DIR)/bl31.bin
>  endif

So this code means that you can either use the bl31 as ELF *or* the
bl31 as binary. So I believe it should not be possible to select both.
Therefore, I would suggest to instead have:

config BR2_TARGET_UBOOT_NEEDS_ATF_BL31
        bool "U-Boot needs ATF BL31"
	... as it already exists ...

choice
	prompt "U-Boot ATF BL31 format"
	default BR2_TARGET_UBOOT_NEEDS_ATF_BL31_BIN

config BR2_TARGET_UBOOT_NEEDS_ATF_BL31_BIN
	bool "bl31.bin"

config BR2_TARGET_UBOOT_NEEDS_ATF_BL31_ELF
	bool "bl31.elf"

endchoice

And then use that in both arm-trusted-firmware.mk and uboot.mk.

What do you think ?

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com