From: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/2] ARM: qemu-arm: define fdt_addr_r
Date: Thu, 18 Oct 2018 01:25:03 +0300 [thread overview]
Message-ID: <20181018012503.736bd2bb@thinkpad> (raw)
In-Reply-To: <cf1fbe26-f998-a8d9-c21f-2ea9c490b92f@suse.de>
Hi Alexander,
On Tue, 16 Oct 2018 15:04:26 +0200
Alexander Graf <agraf@suse.de> wrote:
...
> >
> >> Glancing at cmd/pxe.c,
> >> there is a problem though, in that if ${fdt_addr_r} were defined,
> >> a PXE file using the FDTDIR directive would attempt loading a dtb
> >> file named "<NULL>-qemu-arm.dtb" instead of falling back to using
> >> ${fdt_addr}. That bug would need to be fixed first before applying
> >> this patch.
>
> Well, and that load will fail and everyone's happy, no?
No, because currently if DTB loading from the filesystem/tftp is
attempted and it fails, it aborts the boot. It doesn't matter if it's
via a 'FDT' or 'FDTDIR' directive. In the case of typical hardware
that's probably the desired behaviour.
I guess the qemu_arm + FDTDIR case can be fixed by not attempting
a .dtb load if the default fdtfile is not known due to $soc or $board
being unset. At least I doubt that some other board could be relying
on a filename containing literally "<NULL>" :)
> IMHO we should
> fall back to $fdtcontroladdr always
FWIW, to me the idea of passing $fdtcontroladdr to the OS has always
filled me with dread. On top of the usual backwards- and
forwards-compatibility problems that happen when mixing and matching
kernels and DTBs from different releases, you now have to deal with
issues like U-Boot specific .dts that are majorly diverged from Linux
ones, or where the .dts is otherwise from Linux but the U-Boot specific
additions break it for Linux, or where the .dts used is wrong for the
specific hardware revision but close enough for U-Boot's purposes,
and so on...
- Tuomas
next prev parent reply other threads:[~2018-10-17 22:25 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-12 5:07 [U-Boot] [PATCH 1/2] efi_loader: rework fdt handling in distro boot script AKASHI Takahiro
2018-10-12 5:07 ` [U-Boot] [PATCH 2/2] ARM: qemu-arm: define fdt_addr_r AKASHI Takahiro
2018-10-15 1:01 ` Tuomas Tynkkynen
2018-10-15 5:14 ` AKASHI Takahiro
2018-10-16 13:04 ` Alexander Graf
2018-10-17 22:25 ` Tuomas Tynkkynen [this message]
2018-10-18 7:25 ` Alexander Graf
2018-10-19 6:33 ` AKASHI Takahiro
2018-10-19 7:46 ` Alexander Graf
2018-10-19 8:17 ` AKASHI Takahiro
2018-10-24 10:36 ` Tuomas Tynkkynen
2018-10-16 13:15 ` [U-Boot] [PATCH 1/2] efi_loader: rework fdt handling in distro boot script Alexander Graf
2018-10-18 2:07 ` AKASHI Takahiro
2018-10-18 7:31 ` Alexander Graf
2018-10-19 7:20 ` AKASHI Takahiro
2018-10-19 7:31 ` Alexander Graf
2018-10-19 8:32 ` AKASHI Takahiro
2018-10-19 8:50 ` Alexander Graf
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=20181018012503.736bd2bb@thinkpad \
--to=tuomas.tynkkynen@iki.fi \
--cc=u-boot@lists.denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
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;
as well as URLs for NNTP newsgroup(s).