[PATCH] Fix PXA-27x/3xx interrupts when CONFIG_PXA_HAVE_ISA_IRQS=y

[Marc Zyngier]

On Wed, 4 Nov 2009 11:20:53 +0800
Eric Miao <eric.y.miao at gmail.com> wrote:

> On Wed, Nov 4, 2009 at 10:27 AM, Haojian Zhuang
> <haojian.zhuang at gmail.com> wrote:
> > On Tue, Nov 3, 2009 at 3:04 PM, Marc Zyngier <maz at misterjones.org>
> > wrote:
> >>
> >> Commit d2c37068429b29d6549cf3486fc84b836689e122 ([ARM] pxa:
> >> initialize default interrupt priority and use ICHP for IRQ
> >> handling) broke ISA interrupt support on PXA-27x/3xx.
> >>
> >> In such a case, PXA_IRQ(0) != 0, and the IRQ number computed from
> >> ICHP must be offset by PXA_IRQ(0).
> >>
> >> Tested on an Arcom Zeus (PXA-270).
> >>
> >> Signed-off-by: Marc Zyngier <maz at misterjones.org>
> >> ---
> >>  arch/arm/mach-pxa/include/mach/entry-macro.S |    3 +++
> >>  1 files changed, 3 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-pxa/include/mach/entry-macro.S
> >> b/arch/arm/mach-pxa/include/mach/entry-macro.S index
> >> 2418806..f7eb9d8 100644 ---
> >> a/arch/arm/mach-pxa/include/mach/entry-macro.S +++
> >> b/arch/arm/mach-pxa/include/mach/entry-macro.S @@ -46,5 +46,8 @@
> >>                beq     1001f
> >>                bic     \irqstat, \irqstat, #0x80000000
> >>                mov     \irqnr, \irqstat, lsr #16
> >> +#ifdef CONFIG_PXA_HAVE_ISA_IRQS
> >> +               add     \irqnr, \irqnr, #(PXA_IRQ(0))
> >> +#endif
> 
> The #ifdef here might not be necessary since PXA_IRQ() has already
> encoded the difference, check arch/arm/mach-pxa/include/mach/irqs.h
> 
> >>  1001:
> >>                .endm
> >> --
> >> 1.6.0.4
> > Hi Marc,
> >
> > I have a question on this. Do you use CONFIG_PXA_HAVE_ISA_IRQS in
> > pxa270? In my patch, I only enable interrupt priority in pxa27x and
> > pxa3xx since silicon can support this feature. And this feature
> > isn't supported by pxa25x.
> >
> > I also find that CONFIG_PXA_HAVE_ISA_IRQS is only used in pxa25x. Is
> > it right? So I think that we needn't add this into pxa27x and
> > pxa3xx. What's your opinion?
> >
> 
> Haojian,
> 
> CONFIG_PXA_HAVE_ISA_IRQS is used on some platforms which emulates
> ISA expansion slots so some legacy ISA cards can still be used on pxa
> platforms, not necessarily related to pxa25x, could be pxa27x and
> pxa3xx. We need to take a look into the patch indeed.
> 

Haojian, Eric,

Eric is right indeed, and I should probably have given more details
about the context.

The Arcom Zeus is a pxa270 based system with a PC-104 bus (basically
an ISA bus with a different form-factor). On such a system, the first
16 interrupts are reserved to ISA interrupts, so ISA drivers don't get
confused with an IRQ number from outer space... Hence the need to add
PXA_IRQ(0) to the IRQ number.

While the only in-tree user of this feature is the Arcom Viper
(pxa255), I want to submit support for the Arcom Zeus "real soon now",
and this patch (or any variation on the same theme) is needed for the
system to simply boot. 

Note that it was doing fine up to 2.6.31, so this is actually a
regression from commit 57a7a62eb65b35f51814382b0841ff99be242880.

	M.
-- 
I'm the slime oozin' out from your TV set...