Re: [Xenomai-core] [PATCH] Adeos support for 2.6.18 merged PowerPC architecture.

[Philippe Gerum <rpm@xenomai.org>]

On Tue, 2006-12-05 at 18:37 +0100, Wolfgang Grandegger wrote:
> Jan Kiszka wrote:
> > Wolfgang Grandegger wrote:
> >> Benjamin Zores wrote:
> >>> On Tue, 05 Dec 2006 11:17:07 +0100
> >>> Wolfgang Grandegger <wg@domain.hid> wrote:
> >>>
> >>>> I have now a preliminary patch for adeos-ipipe-2.6.19-ppc-1.5-00. The
> >>>> porting was rather straight-forward, as the ppc tree does not use the
> >>>> new "genirq" interface, in contrast to the powerpc tree (that's what
> >>>> you have realized as well).
> >>> Well, i guess the old "ppc" arch is bound to die sooner or later.
> >>> New developments should always be done against "powerpc" arch imho.
> >> Well, the powerpc tree is still highly experimental and only a few
> >> embedded boards are already supported. I guess it will take a long time
> >> before the ppc tree finally gets buried, especially because porting is
> >> not really trivial (due to OF, IRQ layer, etc.),
> >>
> >>>> Therefore the port of the powerpc tree should be based on Philippe's
> >>>> new adeos-ipipe-2.6.19-i386-1.6-00. Unfortunately, I still do not
> >>>> have a board by hand supported by the powerpc tree.
> >>> I haven't had much much time investigating the problem till now.
> >>> But from what i've seen from Philippe's splitted patches, many of them
> >>> that were supposed to be generic (i.e. don't have i386 in their name)
> >>> still have references to x86 changes.
> >>> Is it a normal behavior ?
> >> Unfortunately, "generic" applies only to the Linux part. I realized,
> >> that the new IPIPE support for the genirqs requires even more
> >> arch-specific modifications than the old interface :-( on PowerPC.
> > 
> > How comes? I haven't found time to analyse this for the latest x86
> > patch, but there it should be "more generic" than before. Do you think
> > this is a genirq issue or an I-pipe problem?
> 
> Well, it's nothing serious and we should discuss this issue in a 
> separated thread. I just wanted to have a closer look to the new port 
> before asking. At a first glance I saw that the irq_chip structure has 
> two new elements, ipipe_ack and ipipe_eoi. This requires patching of 
> every PIC interface. There are a few for x86 but plenty for PowerPC. 
> Philippe, is this really necessary? I would prefer the old style using 
> "#ifndef CONFIG_IPIPE" around the "chip->ack" in common code.

As just replied to Jan, this is a matter of the arch maintainer's taste.
If you ask me, I would see no issue changing kernel/irq/chip.c on a
per-port basis, for implementing the best/safest approach. Changes in
the I-pipe core layer are not likely to happen there, anyway, so I don't
see any maintenance hell showing up because we fork the implementation
there.

> 
> Wolfgang,
> 
> _______________________________________________
> Xenomai-core mailing list
> Xenomai-core@domain.hid
> https://mail.gna.org/listinfo/xenomai-core
-- 
Philippe.