[PATCH v2 5/7] doc: fit: add dm-verity boot parameter documentation

[Simon Glass]

Hi Daniel,

On 2026-04-16T01:46:15, Daniel Golle <daniel at makrotopia.org> wrote:
> doc: fit: add dm-verity boot parameter documentation
>
> Add documentation for CONFIG_FIT_VERITY which allows U-Boot to
> construct dm-mod.create= and dm-mod.waitfor= kernel command-line
> parameters from dm-verity metadata embedded in FIT filesystem
> sub-images.
>
> The new document covers the relationship between FIT loadable indices
> and the /dev/fitN block devices that the Linux uImage.FIT block driver
> creates, provides a complete .its example with a dm-verity-protected
> SquashFS root filesystem, describes all required and optional dm-verity
> subnode properties and explains how mkimage generates the verity
> metadata automatically.
>
> dm-verity is only supported for external-data FIT images (mkimage -E);
> mkimage aborts with an error if the flag is omitted.
>
> Signed-off-by: Daniel Golle <daniel at makrotopia.org>
>
> doc/usage/fit/dm-verity.rst | 282 ++++++++++++++++++++++++++++++++++++++++++++
>  doc/usage/fit/index.rst     |   1 +
>  2 files changed, 283 insertions(+)

> diff --git a/doc/usage/fit/dm-verity.rst b/doc/usage/fit/dm-verity.rst
> @@ -0,0 +1,282 @@
> +.. note::
> +
> +   `veritysetup format is invoked with --no-superblock, so no
> +   on-disk superblock is written between the data and hash regions.
> +   The Merkle hash tree is appended directly to the image data within
> +   the FIT external data section. Consequently hash-start-block
> +   equals num-data-blocks`.

This is only true when data-block-size equals hash-block-size -- in
the general case hash-start-block = data_size / hash_block_size versus
num-data-blocks = data_size / data_block_size

So can you update the comment?

Reviewed-by: Simon Glass <sjg at chromium.org>

Regards,
Simon