Subject: Re: [PATCH] drm/amdgpu: replace readq/writeq with atomic64 operations

From: Christoph Hellwig <[email-masked]>
Date: Wed, 7 Aug 2019 00:08:34 -0700

On Wed, Aug 07, 2019 at 10:56:40AM +0800, Tao Zhou wrote:
> readq/writeq are not supported on all architectures

NAK.  You must not use atomic_* on __iomem (MMIO) memory.