Messages in this thread |  | | Date | Mon, 20 Nov 2006 22:21:27 +0100 (CET) | From | Guennadi Liakhovetski <> | Subject | Re: [PATCH] serial: Use real irq on UART0 (IRQ = 0) on PPC4xx systems |
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On Mon, 20 Nov 2006, Russell King wrote:
> > On Mon, 20 Nov 2006 12:54:32 +0100 (MET) > > Stefan Roese <ml@stefan-roese.de> wrote: > > > Let's see, if I got this right. You mean that on such a platform, where 0 is a > > > valid physical IRQ, we should assign another value as virtual IRQ number (not > > > 0 and not -1 of course). And then the platform "pic" implementation should > > > take care of the remapping of these virtual IRQ numbers to the physical > > > numbers. > > Since IRQ0 is not valid, can we arrange for the generic interrupt > infrastructure to always fail it's allocation, and then remove the > utterly unused bloatful irq_desc[0] ? > > Didn't think so since x86 folk would scream. Wait a moment, x86 can > map IRQ0 to some other number for the timer interrupt, just like > other architectures are being forced to map their UART interrupts.
I think, what Russell means, is this:
#define is_real_interrupt(irq) ((irq) != NO_IRQ)
where the NO_IRQ macro has been introduced a LONG time ago specifically for this purpose, and is conveniently defined on some platforms to (unsigned int)-1 or similar, including asm-powerpc/irq.h. And yes, this has been discussed MANY times.
Thanks Guennadi --- Guennadi Liakhovetski - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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