[PATCH] perf/arm-cmn: Add shutdown routine

[Geoff Blake]

On Thu, 19 Jan 2023, Robin Murphy wrote:
 
> If you have a convincing argument that returning IRQ_NONE for unexpected
> spurious interrupts is a real and important concern, then please propose
> a general solution, because if it matters for arm-cmn then it matters
> for hundreds of other drivers too, by rough estimate:
> 
> $ git grep -l IRQ_NONE '*.c' | xargs git grep -L IRQF_SHARED | wc -l
> 834

The general solution for IRQ_NONE exists in the layer above the 
driver, it complains with a visible warning that something might be wrong 
and then moves on. Nothing more is needed.

Your shutdown routine that flips DT_EN in CMN_DT_DTC_CTL is sufficient, as 
after some testing it solves the problem with left over IRQs for my kexec 
use case.  

-Geoff