Re: [PATCH v2 4/5] ARC: MCIP: Set an initial affinity value in idu_irq_map

From: Vineet Gupta
Date: Wed Oct 26 2016 - 12:17:49 EST


On 10/26/2016 07:05 AM, Marc Zyngier wrote:
> It definitely feels weird to encode the interrupt affinity in the DT
> (the kernel and possible userspace usually know much better than the
> firmware). What is the actual reason for storing the affinity there?

The IDU intc supports various interrupt distribution modes (Round Robin, send to
one cpu only etc) whcih in turn map to affinity setting. When doing the DT
binding, we decided to add that this to DT to get the "seed" value for affinity -
which user could optionally changed after boot. This seemed like a benign design
choice at the time.

Thx,
-Vineet