From: Michael Ellerman <mpe@ellerman•id.au>
To: Arnd Bergmann <arnd@arndb•de>
Cc: linuxppc-dev@lists•ozlabs.org, linuxppc-dev@ozlabs•org, thuth@redhat•com
Subject: Re: [PATCH 1/6] powerpc/kconfig: Move NR_IRQS into "Kernel Options"
Date: Mon, 12 Oct 2015 22:07:45 +1100 [thread overview]
Message-ID: <1444648065.31951.3.camel@ellerman.id.au> (raw)
In-Reply-To: <7516455.YEROTAngT1@wuerfel>
On Mon, 2015-10-12 at 12:30 +0200, Arnd Bergmann wrote:
> On Monday 12 October 2015 21:00:25 Michael Ellerman wrote:
> > On Thu, 2015-10-08 at 23:30 +0200, Arnd Bergmann wrote:
> > > On Friday 09 October 2015 08:09:12 Michael Ellerman wrote:
> > > > Currently the NR_IRQS option sits at the top level, which is ugly in
> > > > menuconfig. It's not something users will commonly need to worry about
> > > > so move it into "Kernel Options".
> > >
> > > Is this option actually still meaningful at all, when you select CONFIG_SPARSE_IRQ
> > > unconditionally?
> >
> > It's still used for #define NR_IRQS, which is still used by the generic irq
> > code and also some drivers.
>
> Drivers shouldn't use it, and I don't see any driver using it that can be
> enabled on powerpc.
>
> The question is rather whether you have any devices on powerpc that
> get a hardwired IRQ number from a statically defined platform device
> rather from DT.
>
> If there are any ISA devices, the driver might try to use an interrupt
> number that is hardcoded in the driver as a number from 0 to 15.
> I guess that could happen on old CHRP or 6xx machines.
>
> > So we need some value for that, whether it needs to be user defined or if we
> > could just pick a value I'm not sure. x86 seem to just define it based on
> > NR_CPUs and some other factors.
>
> What happens if you set it to 16?
Yeah, this builds and boots at least on pseries KVM.
diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index e8e3a0a04eb0..35fba282b7f9 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -23,11 +23,8 @@ extern atomic_t ppc_n_lost_interrupts;
/* This number is used when no interrupt has been assigned */
#define NO_IRQ (0)
-/* Total number of virq in the platform */
-#define NR_IRQS CONFIG_NR_IRQS
-
-/* Same thing, used by the generic IRQ code */
#define NR_IRQS_LEGACY NUM_ISA_INTERRUPTS
+#define NR_IRQS NR_IRQS_LEGACY
extern irq_hw_number_t virq_to_hw(unsigned int virq);
cheers
next prev parent reply other threads:[~2015-10-12 11:07 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-08 21:09 [PATCH 1/6] powerpc/kconfig: Move NR_IRQS into "Kernel Options" Michael Ellerman
2015-10-08 21:09 ` [PATCH 2/6] powerpc/kconfig: Move sysdev Kconfig later Michael Ellerman
2015-10-09 5:54 ` Thomas Huth
2015-10-08 21:09 ` [PATCH 3/6] powerpc/kconfig: Move bitness & endian options to the top Michael Ellerman
2015-10-08 21:09 ` [PATCH 4/6] powerpc/kconfig: Move SCOM_DEBUGFS into "Kernel Hacking" Michael Ellerman
2015-10-08 21:09 ` [PATCH 5/6] powerpc/kconfig: Move cpu options after platform options Michael Ellerman
2015-10-09 5:47 ` Thomas Huth
2015-10-12 21:47 ` Scott Wood
2015-10-13 0:11 ` Michael Ellerman
2015-10-08 21:09 ` [PATCH 6/6] powerpc/kconfig: Cell CPU options should depend on PPC_CELL Michael Ellerman
2015-10-09 5:48 ` Thomas Huth
2015-10-08 21:30 ` [PATCH 1/6] powerpc/kconfig: Move NR_IRQS into "Kernel Options" Arnd Bergmann
2015-10-12 10:00 ` Michael Ellerman
2015-10-12 10:30 ` Arnd Bergmann
2015-10-12 11:07 ` Michael Ellerman [this message]
2015-10-12 11:50 ` Arnd Bergmann
2015-10-13 0:28 ` Michael Ellerman
2015-10-13 12:07 ` Arnd Bergmann
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