fedora for ARM

[Lennert Buytenhek]

On Mon, Jun 04, 2007 at 01:10:55PM +0200, Linus Walleij wrote:

> Hi Lennert, your contributions to ARM Linux have not gone unnoticed.
> Nice to see you here!

Thanks. :-)


> >I'm posting here because I would really really like to get the relevant
> >diffs merged back into Fedora.
> 
> The diffs look nice so IMHO should simply be applied, just that you'll 
> probably have to open BZ entries for each and every one of them and push 
> each individual maintainer to just do it...

ACK, I'll do that (after making sure the patches rebased to F8
actually result in working packages.)


> A bit off-topic questions:
> 
> 1. What is the target system(s) you're using? I for one have a very
>    vague understanding of what lab boards etc may be used for running
>    ARM Fedora.

I have a lot of different boards (I probably have ~30 ARM boards by
now, not counting my PCI RAID controllers :-), the main ones being:
- iop.wantstofly.org: Intel IQ81342EX dev board.  ATX form factor,
  dual-core 800MHz IOP342 CPU w/1M total L2 cache, DDR2, 1 PCI-E slot,
  1 64b/133MHz PCI-X slot, dual on-board e1000.  Silicon Image SATA
  controller on PCI card, SATA disk.
- orion.wantstofly.org: ATX form factor, Marvell Orion2 dev board,
  500MHz/600MHz Orion2 CPU, DDR2, on-chip GigE, 1 PCI-E slot, 3
  64b/133MHz PCI-X slots.  SATA controller on PCI card, SATA disk.
- n2100.wantstofly.org: Thecus n2100 NAS appliance, 600 MHz IOP80219
  CPU, on-board dual GigE and SATA controllers, 2 SATA bays, 1 SATA
  disk.

(Both IOP boards are supported in the upstream kernel w/o any
patching needed, and for the Orion, patches have been submitted.)

But the (userland) packages that we carry should run fine on any
ARMv5-compliant CPU.


> 2. As I understand it you employ the Fedora/x86 style of not using a
>    cross-compiler to build these packages, but rather build them with
>    ARM on ARM.

Yes.


>    I am aware of some RPM derivatives like those used by MontaVista,
>    that employ a cross-compiler instead. What are your thought on
>    these issues?

That's something we definitely want/plan to do, and hopefully in
such a form that it makes sense to merge back into Fedora.

Not yet in this stage, though -- IMHO it makes a lot more sense to
get the base ARM support in Fedora right first than trying to cram in
ARM support together with various intrusive changes to slim down
packages and to make cross-compiling work.  (Sure, a lot of ARM use
cases can benefit from such changes, but they are still orthogonal
efforts.)


>    Have you tested both solutions and come to the conclusion that
>    the all-ARM-enclosed build system is the way to go?

For building the regular 'upstream' Fedora ARM package repositories,
building natively makes the most sense now (as Fedora generally doesn't
support cross-compiling yet) and it most likely will continue to make
the most sense in the future, as there's some things that you simply
can't do when cross-compiling (and there will always be packages that
do not lend themselves to cross-compiling), and we'd like the main
package repo to stay as close to Fedora as possible.

When you start doing board-specific customisations, being able to
cross-compile some designated subset of Fedora packages makes a ton
of sense to me, and as I said, that's definitely something where
we'd like to go, but not yet in this stage, and it's possible that
this will never be non-intrusive enough and make enough sense for
general use to be merged back into Fedora -- but we'll see.