Re: [Buildroot] [PATCH v4 2/2] board/lx2160ardb: new platform

From: Thomas Petazzoni via buildroot <buildroot@buildroot.org>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: buildroot@buildroot.org,
	Brandon Maier <Brandon.Maier@collins.com>,
	Ioana Ciornei <ciorneiioana@gmail.com>,
	Romain Naour <romain.naour@smile.fr>,
	Vincent Jardin <vjardin@free.fr>, Julien Olivain <ju.o@free.fr>,
	Akhilesh Nema <nemaakhilesh@gmail.com>
Subject: Re: [Buildroot] [PATCH v4 2/2] board/lx2160ardb: new platform
Date: Fri, 2 Jan 2026 23:33:08 +0100	[thread overview]
Message-ID: <20260102233308.49adad9a@windsurf> (raw)
In-Reply-To: <20250830173313.164981-3-olteanv@gmail.com>

Hello Vladimir,

On Sat, 30 Aug 2025 20:33:13 +0300
Vladimir Oltean <olteanv@gmail.com> wrote:

> Add Buildroot support for the NXP LX2160A-RDB (reference design board).
> This is configured here to boot from the SD card. To my surprise, NXP
> RCWs for LX2160A rev2 silicon don't have a pre-existing example for SD
> boot, so until one is available, include the RCW through board files.
> 
> I would have been fine with the default U-Boot environment, except that
> I would like to ship the MC firmware deployed as a file in the
> filesystem, and that requires a custom 'mcinitcmd' environment variable
> to load it. Thus, the 'env default -a' output was customized and
> included here in its entirety.
> 
> Previous review feedback said that the U-Boot environment is too large:
> https://lore.kernel.org/buildroot/2hhshlixqffg7r3o33klqzyvbxnpwllhhkskbi5igtewh6htlg@5huoxuxspqlv/
> Short of me starting to strip away features, the best I can do is to
> amortize the cost by taking away some variables and placing them in
> other U-Boot environment variable files which can be reused.

I'm still not excited by these massive U-Boot environments. Imagine we
start to have something like this for all boards? It would be a real
mess.

Options that I see:

- Since anyway you're rewriting the entire environment, why does it
  matter to use extlinux? extlinux is great when the U-Boot environment
  is already set to use it. But here you anyway override the whole
  environment, so you could just as well use a trivial environment that
  just implements the bootcmd that works for the Buildroot use-case.

- You could use the new "U-Boot Standard Boot" mechanism, which
  replaces the madness of U-Boot scripts/environment variables by
  something much nicer implemented in C, and which needs only a handful
  of environment variables.

> diff --git a/configs/lx2160ardb_defconfig b/configs/lx2160ardb_defconfig
> new file mode 100644
> index 000000000000..02cab7754e28
> --- /dev/null
> +++ b/configs/lx2160ardb_defconfig
> @@ -0,0 +1,58 @@
> +BR2_aarch64=y
> +BR2_cortex_a72=y
> +BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_12=y

I think we now want to use external toolchains for new defconfigs.
However, I'll be happy to merge it without this change as it's kind of
a new requirement, and you've been trying to get this defconfig in for
quite some time already.

Honestly the rest looks good, it's really just the madness of the
U-Boot environment that I dislike.

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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