Yocto - creating a dependency for WIC to cpio.gz image

Question

I'm creating a small Yocto distro that should work in RAM on tmpfs. I use the WIC configuration in the following way:

part /boot --source bootimg-efi --sourceparams="loader=grub-efi,initrd=${PN}-${MACHINE}.cpio.gz,file=${PN}-${MACHINE}.cpio.gz" --ondisk sda --label msdos --active --align 1024
bootloader --ptable gpt --timeout=0 --append="rootfstype=tmpfs rootflags=size=2G console=ttyS0,115200 console=tty0"

I also add IMAGE_FSTYPES_append = " cpio.gz " to my local.conf, so it builds the cpio.gz archive from my rootfs.

My problem is very straightforward - when WIC runs, it tries to create the wic file before it is done with creating the rootfs cpio.gz, and therefore the build fails. What I need is to create a dependency, something that will hold WIC scripts until the cpio.gz is ready. Does anyone know how to achieve it? Can, for instance, WKS_FILE_DEPENDS be used?

Here is the failure:

| ERROR: _exec_cmd: cp .../poky/build/tmp/deploy/images/genericx86-64/core-image-minimal-genericx86-64.cpio.gz .../poky/build/tmp/work/genericx86_64-poky-linux/core-image-minimal/1.0-r0/deploy-core-image-minimal-image-complete/core-image-minimal-genericx86-64-20191121151711/tmp.wic.k00ckxmk/hdd/boot returned '1' instead of 0
| output: cp: cannot stat '.../poky/build/tmp/deploy/images/genericx86-64/core-image-minimal-genericx86-64.cpio.gz': No such file or directory

Currently I bypass the problem by running the wic tool manually after the build. I had to use IMAGE_FSTYPES_remove = " wic wic.bmap hddimg " in my local.conf for that. The command for running wic then is:

wic create ../meta-mylayer/wic/myimage.wks -e core-image-minimal

Thanks!

EDIT: Maybe the problem is not in creating the required dependency, but in the way I create the image? I just want a UEFI boot, a kernel, and a cpio.gz file with a complete rootfs which will gets mounted on boot. This is not an initramfs, but a complete rootfs that I need there. Except the problematic dependency the resulting image does exactly what I need.

Parthiban Parthiban · Accepted Answer · 2019-11-21T11:49:53

You can specify the dependency with WIC in 2 ways.

Using do_image_wic: The final task to create the WIC is do_image_wic. So you can add dependency for creating your initrd/initramfs image to this task as below,

do_image_wic[depends] += "image-base-initramfs:do_image_complete"

You need to specify this in your WIC image creation recipe. For this example,

DESCRIPTION = "My image"

inherit core-image

export IMAGE_BASENAME = "image-base"
IMAGE_FSTYPES = "wic.xz"
DEPENDS += "image-base-initramfs"
do_image_wic[depends] += "image-base-initramfs:do_image_complete"
WKS_FILES = "my.wks"

Here image-base is used for creating the WIC using my.wks. It waits for the initramfs to complete the building. In image-base-initramfs you will create the initramfs image.

To add, you can also do this with INITRAMFS_IMAGE when using kernel fitImage.

Using WKS_FILE_DEPENDS: You can add any bitbake recipe to dependency before creating the WIC image. Adding image-base-initramfs to this variable will wait for it to complete the initramfs image. We also have WKS_FILE_DEPENDS_BOOTLOADERS when depending on bootloader to complete in WIC creation.

Yocto - creating a dependency for WIC to cpio.gz image

1 Answers