Files are not installed from recipe

I'm trying to create a custom recipe to sign a u-boot image generated from u-boot.bb.

I have 2 custom recipes:

1. u-boot.bb - clones, compiles and deploys u-boot resulting u-boot.elf.
2. u-boot-sign.bb - depends on u-boot.bb. Gets u-boot.elf, passes it through
                    custom signing procedure and deploys the result.

For signing I am forced to use a custom procedure which is in a form of python scripts located in external repository.

The part which causes a problem is accessing a deployed u-boot.elf binary file from u-boot.bb recipe. I cannot find a way to expose u-boot.elf binary file to a u-boot-sign.bb recipe.

What should be the correct way of exposing an image binary file from one recipe, to be accessed, signed and deployed in another recipe?

Solution

For the purpose of sharing the files between recipes and between cross-compilation scope, I used ${datadir} when installing the binaries (via do_install). This allowed me to access all files described by FILES:${PN} via recipe-sysroot.

u-boot.bb - exporting recipe:

…
do_install() {
    install -d ${D}${datadir}/u-boot-2016/
    install -m 0644 ${B}/${UBOOT_ELF_BINARY} ${D}${datadir}/u-boot-2016
}

FILES:${PN} = "${datadir}/u-boot-2016"
…

u-boot-sign.bb - depending recipe

…
DEPENDS += " u-boot python3-native"

do_sign() {
    ${STAGING_BINDIR_NATIVE}/python3-native/python3 sign.py \
                -i ${RECIPE_SYSROOT}${datadir}/u-boot-2016/${UBOOT_ELF_BINARY}

}
…

Inspiration from Here

Edit

I was advised not to transfer files like this using ${datadir}. For intermediate files the better approach would be to use to use /firmware as it is done in meta-arm.

u-boot.bb - exporting recipe:

…
do_install() {
    install -D -p -m 0644 ${B}/${UBOOT_ELF_BINARY} ${D}/firmware/${UBOOT_ELF_BINARY}
}

FILES:${PN} = "/firmware"
SYSROOT_DIRS += "/firmware"
…

u-boot-sign.bb - depending recipe

…
DEPENDS += " u-boot python3-native"

do_sign() {
    ${STAGING_BINDIR_NATIVE}/python3-native/python3 sign.py \
                -i ${RECIPE_SYSROOT}/firmware/u-boot-2016/${UBOOT_ELF_BINARY}
}
…

It also requires to add /firmware to SYSROOT_DIRS.