Hi Simon,
Am 02.08.2022 um 14:41 schrieb Simon Glass:
Hi Stefan,
On Tue, 2 Aug 2022 at 06:29, Stefan Herbrechtsmeier
<stefan.herbrechtsmeier-...@weidmueller.com> wrote:
From: Stefan Herbrechtsmeier <stefan.herbrechtsme...@weidmueller.com>
Remove header from compressed data because this is uncommon, not
supported by U-Boot and incompatible with external compressed artifacts.
The header was introduced as part of commit eb0f4a4cb402 ("binman:
Support replacing data in a cbfs") to allow device tree entries to be
larger that the compressed contents. Regarding the commit "this is
necessary to cope with a compressed device tree being updated in such a
way that it shrinks after the entry size is already set (an obscure
case)". This case need to be fixed without influence the compressed data
by itself.
I was not able to find a way around this due to the chicken-and egg
problem. Compressed data has an unpredictable size and adding an extra
uncompressed byte may increase or decrease the compressed size.
Is it possible to use the `pad-after` attribute to record the unused
space. In this case it is possible to calculate the size of the
compressed data.
Do you have a test for this use case?
So my solution was to add the header.
Is the header used outside of binman? I don't spot it in the decompress
fitImage implementation.
It is optional though, so can we perhaps have a property in the
description to enable it?
Is this header needed and supported outside of binman?
At the moment the header is incompatible and not well documented. It
took me some time to find out why my gzip compression via binman doesn't
work as expected because I assume a compatibility between binman
compress and fitImage decompress.
Regards
Stefan
