[PATCH 15/18] irqchip/apple-aic: Add support for the Apple Interrupt Controller

[Arnd Bergmann]

On Mon, Feb 8, 2021 at 10:25 AM Marc Zyngier <maz at kernel.org> wrote:
> On Thu, 04 Feb 2021 20:39:48 +0000, Hector Martin <marcan at marcan.st> wrote:

> > +{
> > +     return readl(ic->base + reg);
>
> Please consider using the _relaxed accessors, as I don't think any of
> these interacts with memory (apart from IPIs, of course).

MSI interrupts require serializing with DMA, so at the minimum I think there
needs to be something that ensures that DMA from device into memory
has completed before delivering the completion interrupt to a driver. This
may already be implied when the AIC is entered, but this is hard to know
without actual hardware specs.

       Arnd