Re: Two different interrupt-parents

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

On Mon, Apr 16, 2012 at 09:55:09AM -0400, jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
> On Mon, Apr 16, 2012 at 12:53 AM, David Gibson
> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> > On Mon, Apr 16, 2012 at 04:14:25AM +0000, Sethi Varun-B16395 wrote:
> >> You can use a 4 cell interrupt specifier (we use that in case of embedded power architecture platforms)
> >> - First cell corresponds to one of the four cascade lines (coming from the cascaded pic)
> >> - Second cell provides the interrupt sense information
> >> - Third one tells the interrupt subtype (in your case should be the cascade power interrupt type)
> >> - Fourth cell communicates the interrupt number corresponding to the cascaded pic.
> >>
> >> There would be a single interrupt parent, which is the system interrupt controller. You would have
> >> to translate the four cell interrupt specifier and also add cascaded interrupt handling
> >> for the shared interrupt line.
> >
> > No, don't do that.
> >
> > Use the interrupt-map technique described in the thread that got
> > linked earlier.
> 
> If interrupts had syntax like GPIOs this problem wouldn't exist.

Yes, but the interrupt syntax has existed since forever, so it's not
worth creating a new incompatible one which we'd need to teach all the
clients about, when a perfectl good workaround like the interrupt-map
method exists.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson