Oe-core recipe for building and integrating M4 firmware into iMX7 image

Technical Support
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1

Hi,
Is there already a recipe/mechanism/tutorial available of how to easy build and integrate the M4 firmware into an oe-core image?
Thanks in advance.

2

Hi

No, we so far did not try that. The issue is that we don’t know yet how to get a bare bone cross compiler mixed with a linux cross compiler.

Having said that you coud build you binary outside of OE and use a recipe to deply it into the final image.

Max

3

Ok, thanks. The M4 firmware image has to placed within the boot partition (besides uImage and .dtb files). What would be the recommended way to add files to *.bootfs.tar and *.bootfs.tar.xz using ordinary recipes?

4

I don’t have a recommended way currently.

Assuming the m4 binary is called m4.bin, I guess one could with the 2.8 or 2.7 BSP and Toradex Easy Installer images do the following hack:

  • bring the m4.bin file into the ${DEPLOY_DIR_IMAGE} directory (…deploy/image/${MACHINE}) similar to how meta-toradex-bsp-common/recipes-bsp/tezi-metadata/tezi-metadata_0.3.bb does it with the wrapup script and others.
  • get the m4 binary into the bootfs.tar.xz by hacking it into the meta-toradex-bsp-common/classes/image_type_tezi.bbclass, i.e. by adding m4.bin to the end of the bootfs tar line here.

I will create a ticket in our roadmap, so that maybe for future BSP’s we get a cleaner solution.

Max

5

I just realized that it is possible to load the M4 firmware file from the rootfs with ext4load.

6

Thanks for this information.
Did you try it?

7

Yes. i tried it and it works fine.

8

Perfect. Thanks for the feedback.