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From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [PATCH 11/11] bootm: Support string substitution in bootargs
Date: Mon, 19 Oct 2020 16:54:50 +0200	[thread overview]
Message-ID: <283890.1603119290@gemini.denx.de> (raw)
In-Reply-To: <20201019135602.3943835-12-sjg@chromium.org>

Dear Simon,

In message <20201019135602.3943835-12-sjg@chromium.org> you wrote:
> In some cases it is necessary to pass parameters to Linux so that it will
> boot correctly. For example, the rootdev parameter is often used to
> specify the root device. However the root device may change depending on
> whence U-Boot loads the kernel. At present it is necessary to build up
> the command line by adding device strings to it one by one.
>
> It is often more convenient to provide a template for bootargs, with
> U-Boot doing the substitution from other environment variables.
>
> Add a way to substitute strings in the bootargs variable. This allows
> things like "rootdev=%U" to be used in bootargs, with the %U substitution
> providing the UUID of the root device.

Argh, no, please don't.

You add something unconditionally to common code which very few
people need.  U-Boot size is growing all the time because of such
... features.  This may be acceptable on the systems you have in
mind, but I consider this selfish.

Why do we have to add yet another non-standard way of substituting
variables in a string?  Can we not use alreay existing methonds
instead?

Why do you have to use "%U" in your template instead of for example
"${uuid}" ?



Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
If you use modules, you pay the price. Sane embedded solutions
running in "tight" environments don't use modules :-)
    -- Benjamin Herrenschmidt in <1258234866.2140.451.camel@pasglop>

  parent reply	other threads:[~2020-10-19 14:54 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-19 13:55 [PATCH 00/11] bootm: Support substitions in bootargs and add tests Simon Glass
2020-10-19 13:55 ` [PATCH 01/11] env: Allow returning errors from hdelete_r() Simon Glass
2020-10-19 13:55 ` [PATCH 02/11] bootm: Add tests for fixup_silent_linux() Simon Glass
2020-10-19 13:55 ` [PATCH 03/11] bootm: Update fixup_silent_linux() to return an error Simon Glass
2020-10-19 13:55 ` [PATCH 04/11] bootm: Rename fixup_silent_linux() Simon Glass
2020-10-19 13:55 ` [PATCH 05/11] bootm: Add a bool parameter to bootm_process_cmdline_env() Simon Glass
2020-10-19 13:55 ` [PATCH 06/11] bootm: Use size rather than length for CONSOLE_ARG Simon Glass
2020-10-19 13:55 ` [PATCH 07/11] bootm: Split out bootargs environment reading / writing Simon Glass
2020-10-19 14:45   ` Wolfgang Denk
2020-10-20 19:12     ` Simon Glass
2020-10-21  7:02       ` Wolfgang Denk
2020-10-21 15:51         ` Simon Glass
2020-10-19 13:55 ` [PATCH 08/11] bootm: Update bootm_process_cmdline_env() to use flags Simon Glass
2020-10-19 13:56 ` [PATCH 09/11] bootm: Allow updating the bootargs in a buffer Simon Glass
2020-10-19 14:46   ` Wolfgang Denk
2020-10-20 19:12     ` Simon Glass
2020-10-21  6:57       ` Wolfgang Denk
2020-10-21 15:51         ` Simon Glass
2020-10-19 13:56 ` [PATCH 10/11] x86: zimage: Add silent-console processing Simon Glass
2020-10-19 13:56 ` [PATCH 11/11] bootm: Support string substitution in bootargs Simon Glass
2020-10-19 14:43   ` Rasmus Villemoes
2020-10-19 15:50     ` Simon Glass
2020-10-20 13:19       ` Wolfgang Denk
2020-10-19 14:54   ` Wolfgang Denk [this message]
2020-10-19 15:47     ` Michael Walle
2020-10-19 15:52       ` Simon Glass
2020-10-20 13:26         ` Wolfgang Denk
2020-10-20 19:23           ` Simon Glass
2020-10-21  7:16             ` Wolfgang Denk
2020-10-21 15:51               ` Simon Glass
2020-10-22 12:32                 ` Wolfgang Denk
2020-11-03 15:11                   ` Simon Glass
2020-10-19 15:50     ` Simon Glass
2020-10-20 13:17       ` Wolfgang Denk
2020-10-20 19:23         ` Simon Glass
2020-10-19 14:39 ` [PATCH 00/11] bootm: Support substitions in bootargs and add tests Heinrich Schuchardt
2020-10-20 19:12   ` Simon Glass

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