Re: [PATCH 1/2] kernel-fitimage: add support for custom ITS file override

[kavinaya@qti.qualcomm.com]

On Tue, Sep 23, 2025 at 02:28 AM, Adrian Freihofer wrote:

>
> First, two simple findings from today's review meeting:
> * Squash Commits: Please consolidate the two patches into a single
> commit for better clarity and history.
> * Namespace Adherence: The new variable CUSTOM_ITS_FILE should align
> with our existing naming conventions. Please rename it to
> FIT_CUSTOM_ITS_FILE.

Sure. I will consolidate the two patches into a single patch and rename CUSTOM_ITS_FILE to FIT_CUSTOM_ITS_FILE.
> 
> Now, I have a more fundamental question about the current
> implementation, which suggests we might need to explore a different
> approach for this functionality. My concern stems from how the
> do_compile() function handles the ITS file generation:
> 
> do_compile () {
> root_node = 700 lines of Python code prepare the its data
> structure ready to be written into a file.
> 
> # Then just ignore all this and use another (hard-coded?) its file
> custom_its_file = d.getVar('CUSTOM_ITS_FILE')
> if custom_its_file:
> custom_its_file = os.path.join(kernel_deploydir,
> custom_its_file)
> bb.note(f"Using custom ITS file: {custom_its_file}")
> shutil.copyfile(custom_its_file, itsfile)
> else:
> root_node.write_its_file(itsfile)
> 
> # Assemble the FIT image
> root_node.run_mkimage_assemble(itsfile, fitname)
> 
> # Sign the FIT image if required
> root_node.run_mkimage_sign(fitimage)
> }
> 
> As I understand it, the current logic (depending on FIT_* variable
> configurations) appears to execute a significant portion of the
> existing ITS data preparation code—potentially up to 700 lines—only to
> then overwrite the generated output with a custom, possibly hard-coded,
> ITS file. This pattern seems to bypass the intended use of the existing
> generation logic.
>
The existing logic is retained because it performs essential preparation steps beyond ITS generation, such as copying DTBs and other components into the FIT image assembly directory. These steps are required for successful image assembly even when a custom ITS file is used.

Thanks,
Kavinaya