Re: rootfs porting to mipsel 32 bit - MIPS 1004K

James Cowgill <[email protected]> Fri, 09 Oct 2015 14:28:28 +0100
Newsgroups	gmane.linux.debian.ports.mips
Message-ID	<[email protected]>
Hi,

On Fri, 2015-10-09 at 07:54 -0500, Lijun QIN wrote:
> I got an embedded Linux board (mipsel 32 bit - MIPS 1004K) with rootfs.cpio
> .  Unfortunately, the rootfs is pretty old -customized from Debian MIPS
> port release, based on Debian 6.  I need to upgrade it to the latest
> version with gcc 4.9 since our application uses some of C++11 features.  I
> come from ARM/BuildROOT.  After I have read through the webpage
> https://www.debian.org/ports/mips/ ,   not much detailed info was found out
> about porting rootfs.

Firstly, do you need a development system which runs on mipsel? You
might be able to do what you want with cross compilers? Debian has a
mipsel cross compiler but it is only in unstable/testing:
https://packages.debian.org/unstable/g++-5-mipsel-linux-gnu

It you want a full system, it seems to me there are two ways to do
this:

a)
If the rootfs you have works, you could try upgrading it to wheezy and
then jessie using the normal Debian upgrade process. If the rootfs was
heavily customized it may not work though. QEMU could help with this.

b)
To create a new rootfs you can use debootstrap + QEMU. You would first
use debootstrap with the --foreign --arch=mipsel options to download
and extract the packages. Then you copy /usr/bin/qemu-mipsel-static
into the rootfs and you should be able to chroot into the rootfs to
complete the installation process (running debootstrap with --second-
stage).

There is some information about this here:
https://wiki.debian.org/Debootstrap
https://wiki.debian.org/EmDebian/CrossDebootstrap

> Here is my question list that might need your help for advice:
> 
>   It (a)sounds like I need to mipsel linux machine. Any instruction to
> access mipsel-aql-01.debian.org ?

To access one of the Debian machines you'll need to have a DD sponsor
you. Read this: https://dsa.debian.org/doc/guest-account/

Also the machine you want is probably minkus.debian.org.

Having said that you should be able to do everything you need using
QEMU.

>       (b) Any tools available to select packages to build rootfs ?

Either you can install them in the chroot using QEMU, or use the
--include=<packages> option to debootstrap.

Thanks,
James
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