SoC Design and Simulation forum GIC500 :: How to forward interrupts to multiple cores using GICD_IROUTER

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GIC500 :: How to forward interrupts to multiple cores using GICD_IROUTER

danish259 over 7 years ago

Is there a way to forward the interrupts from Descriptor to multiple Cores using GICD_IROUTER ?

Seems the Affinity Routing field in my case is hard-tied to 1.

P.S. The SoC I'm working on, do have 8 ARM cores

+1 Martin Weidmann over 7 years ago

Yes, set GICD_IROUTER<n>.IRM==1. This means "Interrupts routed to any PE defined as a participating node". Where "participating node" means that the core is awake and has the Group the interrupt belongs to enabled.

Note: There is a difference between GICv2 (GIC-400) and GICv3 (GIC-500). With GIC-400 if you selected multiple targets, the interrupt would be sent to multiple targets with the first to respond getting it. With GIC-500/GICv3, the GIC picks one target and sends it there. So a given instance of an interrupt only goes to one place. Although for the next instance the GIC could pick one of the other possible targets.
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0 danish259 over 7 years ago in reply to Martin Weidmann

Martin.. what if the Cores are in WFI state and the interrupt is meant to take all of them out of it ?
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0 Martin Weidmann over 7 years ago in reply to danish259

At least with GICv3, you can't do that with a SPI. You could by sending each an SGI.
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0 Martin Weidmann over 7 years ago in reply to Martin Weidmann

I should add, it wasn't really safe to rely on this with GICv2/GIC-400.
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