[PATCH v2 16/18] boot: pxe_utils: Add extension board devicetree overlay support

[Kory Maincent]

On Thu, 09 Oct 2025 16:50:52 +0200
"Kory Maincent (TI.com)" <kory.maincent at bootlin.com> wrote:

> Add support for scanning and applying extension board devicetree
> overlays during PXE boot. After loading the main board devicetree,
> the system now scans for available extension boards and applies their
> overlays automatically.
> 
> This enables dynamic hardware configuration for systems with extension
> boards during boot scenarios which are using pxe_utils.
> 
> Signed-off-by: Kory Maincent (TI.com) <kory.maincent at bootlin.com>

...

> +
> +	alist_for_each(extension, extension_list) {
> +		char *overlay_file;
> +		ulong size;
> +
> +		len = dir_len + strlen(extension->overlay);
> +		overlay_file = calloc(1, len);
> +		if (!overlay_file)
> +			goto cleanup;
> +
> +		snprintf(overlay_file, len, "%s%s", overlay_dir,
> +			 extension->overlay);
> +
> +		/* Load extension overlay file */
> +		ret = get_relfile_envaddr(ctx, overlay_file,
> +					  "extension_overlay_addr",
> +					  (enum
> bootflow_img_t)IH_TYPE_FLATDT,
> +					  &size);
> +		if (ret < 0) {

Just figured out that it would be nice to have a warning here if the file is
not loaded or found:
printf("Failed loading overlay %s\n", overlay_file);

> +			free(overlay_file);
> +			continue;
> +		}
> +
> +		ret = extension_apply(working_fdt, size);
> +		if (ret) {
> +			free(overlay_file);
> +			continue;
> +		}
> +		free(overlay_file);
> +	}
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com