From: Timur Tabi <timur@freescale•com>
To: Timur Tabi <timur@freescale•com>,
Grant Likely <grant.likely@secretlab•ca>,
linuxppc-dev@ozlabs•org, Arnd Bergmann <arnd@arndb•de>
Subject: Re: Could the DTS experts look at this?
Date: Tue, 12 Feb 2008 17:50:30 -0600 [thread overview]
Message-ID: <47B230C6.9010105@freescale.com> (raw)
In-Reply-To: <20080212233548.GE21230@localhost.localdomain>
David Gibson wrote:
> You don't. If your agent takes a dtb, dtb layout and agent must
> match.
So what I would like to see is a way for the agent to validate the dtb. U-Boot
could currently validate the SOC's compatible field. However, if we add a
special node that contains rules for modifying the rest of the tree, the only
possible way to block older, incompatible U-Boots from accepting the tree is to
bump the version number. Since that is not the right thing to do, the best
approach is to define a new node type that has conditional expression attached
to it. Then we can bump the version.
> In fact, in one way of looking at it that's always what happens: the
> dtb format is defined for passing hardware information from the
> bootloader to the kernel; nothing else. Passing a dtb *into* the
> bootloader is just a bootloader implementation convenience, because
> the possible variations on an output tree are small, so it's useful to
> have a skeleton tree built-in. But in order for the bootloader to
> process those variations correctly, the skeleton *must* be in the
> right format. dtb input to a bootloader must match the bootloaders
> expectations. This has always been true, and will continue to be
> true.
The problem with this approach is that you're replacing data with code, and that
always makes things more difficult.
--
Timur Tabi
Linux kernel developer at Freescale
next prev parent reply other threads:[~2008-02-12 23:50 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-08 23:30 Could the DTS experts look at this? Sean MacLennan
2008-02-10 5:47 ` Arnd Bergmann
2008-02-10 6:05 ` Sean MacLennan
2008-02-11 17:57 ` Timur Tabi
2008-02-11 23:54 ` David Gibson
2008-02-11 23:56 ` David Gibson
2008-02-12 0:21 ` Arnd Bergmann
2008-02-12 0:36 ` David Gibson
2008-02-12 18:51 ` Scott Wood
2008-02-12 23:17 ` David Gibson
2008-02-12 23:41 ` Timur Tabi
2008-02-12 23:50 ` David Gibson
2008-02-12 15:44 ` Timur Tabi
2008-02-12 18:58 ` Grant Likely
2008-02-12 19:08 ` Timur Tabi
2008-02-12 19:34 ` Grant Likely
2008-02-12 19:45 ` Timur Tabi
2008-02-12 20:43 ` Grant Likely
2008-02-12 23:35 ` David Gibson
2008-02-12 23:50 ` Timur Tabi [this message]
2008-02-13 0:10 ` Grant Likely
2008-02-12 23:26 ` David Gibson
2008-02-12 23:47 ` Timur Tabi
2008-02-13 0:08 ` David Gibson
2008-02-13 0:15 ` Grant Likely
2008-02-12 23:21 ` David Gibson
2008-02-11 0:14 ` David Gibson
2008-02-11 2:40 ` Sean MacLennan
2008-02-11 3:11 ` David Gibson
2008-02-11 3:49 ` Sean MacLennan
2008-02-11 23:59 ` David Gibson
2008-02-12 1:07 ` Sean MacLennan
2008-02-12 0:20 ` David Gibson
2008-02-12 0:41 ` Sean MacLennan
2008-02-12 0:48 ` David Gibson
2008-02-12 18:52 ` Scott Wood
2008-02-12 19:03 ` Grant Likely
2008-02-12 19:10 ` Scott Wood
2008-02-17 10:22 ` David Woodhouse
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=47B230C6.9010105@freescale.com \
--to=timur@freescale$(echo .)com \
--cc=arnd@arndb$(echo .)de \
--cc=grant.likely@secretlab$(echo .)ca \
--cc=linuxppc-dev@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox