Specifying the MTD partitions in a device tree

Rogério Brito rbrito at ime.usp.br
Thu May 14 15:48:59 AEST 2015


I am sending this message to Debian/powerpc, Debian/arm lists because and
linuxppc-dev.  While the issue that I'm having is with a powerpc machine,
the arm people may also be of valuable help with device trees, since they
have to deal with them seemingly all the time.

Anyway, the problem that I have is as follows: I have a Kurobox HG (powerpc)
NAS that Riku Voipio donated me a few years ago.

Everything worked fine and I was able to get Debian (since kernel 2.6.20 or
similar) running up to with kernels 2.6.28 (if my memory serves me well).
With kernel 2.6.29, the partitions of the MTD device that this machine has
were not displayed anymore (only one big device was presented to the user).

In a recent exchange [0] with Scott Wood from the linuxppc-dev, I was
finally able to partition the MTD flash device with the original layout of
the device by passing an `mtdparts` option to the kernel.

[0]: http://permalink.gmane.org/gmane.linux.ports.ppc.embedded/80215

It seems, though, that the proper way to fix this issue for good is to
include such description in the DTS files for the particular board (in fact,
at least 2---but potentially 4---boards are affected by this).

I tried a few experiments with writing a patch to the existing dts files,
but I wasn't successful, since I am not sure about a good amount of the
things and I would appreciate some assistance here.

In particular, I don't know if I filled all the fields correctly and, also,
I don't know where I should "graft" the description of the flash chip in the
rest of the device tree.

Can anybody help here? I am sending a verbosely and dirty patch (not yet
suitable for inclusion in the main kernel tree) that I created (and which
didn't work) with as much information that I know about the system, but I
can surely collect more information.

Ideally, I would like to get many of the things automated and add support
for the Kurobox HD/HG to the Debian installer, so that people with these
devices can breathe new life into their systems (instead of the original
2.4.20 kernel that came with it).

I would ge greateful for anybody that can help here. I hope to both learn
and help with the maintainance of such machines.

Once again, thanks a lot for any help,

Rogério Brito.

Rogério Brito : rbrito@{ime.usp.br,gmail.com} : GPG key 4096R/BCFCAAAA
http://cynic.cc/blog/ : github.com/rbrito : profiles.google.com/rbrito
DebianQA: http://qa.debian.org/developer.php?login=rbrito%40ime.usp.br
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