Re: [PATCH] drivers/iommu: Ensure that the queue base address is successfully written during SMMU initialization.

[Will Deacon]

On Sun, Feb 18, 2024 at 09:44:47PM -0800, Daniel Mentz wrote:
> On Sat, Feb 17, 2024 at 9:02 PM ni.liqiang <niliqiang.io@xxxxxxxxx> wrote:
> > If there are no memory barriers, how can we ensure this order?
> 
>  The SMMU registers are accessed using Device-nGnRE attributes. It is
> my understanding that, for Device-nGnRE, the Arm architecture requires
> that writes to the same peripheral arrive at the endpoint in program
> order.

Yup, that's correct. The "nR" part means "non-Reordering", so something
else is going on here.

Will