Messages in this thread | | | Subject | Re: [RFC PATCH v1] irqchip: add support for SMP irq router | From | Marc Zyngier <> | Date | Wed, 6 Jul 2016 09:58:38 +0100 |
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On 05/07/16 20:24, Thomas Gleixner wrote: > On Tue, 5 Jul 2016, Marc Zyngier wrote: >> On 05/07/16 17:59, Sebastian Frias wrote: >>> Well, if you the domains should not be described in the DT and that they should >>> be somehow hardcoded into the drivers' code, it should not be hard indeed. >> >> Hardcoded? No way. You simply implement a route allocator in your >> driver, assigning them as needed. And yes, if you have more than 24 >> interrupts, they get muxed. > > There is one caveat though. Under some circumstances (think RT) you want to > configure which interrupts get muxed and which not. We really should have that > option, but yes for anything which has less than 24 autorouting is the way to > go.
Good point. I can see two possibilities for that:
- either we describe this DT with some form of hint, indicating what are the inputs that can be muxed to a single output. Easy, but the DT guys are going to throw rocks at me for being Linux-specific.
- or we have a way to express QoS in the irq subsystem, and a driver can request an interrupt with a "make it fast" flag. Of course, everybody and his dog are going to ask for it, and we're back to square one.
Do we have a way to detect which interrupt is more likely to be sensitive to muxing? My hunch is that if it is requested with IRQF_SHARED, then it is effectively muxable. Thoughts?
Thanks,
M. -- Jazz is not dead. It just smells funny...
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