Re: [PATCH 09/10] sh: don't allow non-coherent DMA for NOMMU

[Rob Landley]

On 6/26/20 3:07 AM, Christoph Hellwig wrote:
> The code handling non-coherent DMA depends on being able to remap code
> as non-cached.  But that can't be done without an MMU, so using this
> option on NOMMU builds is broken.

I'm working on a nommu j-core board that's doing DMA behind the OS's back at the
moment, which I have a todo item to teach the kernel about. The DMA does not go
through the cache, there's currently a cache flush before looking at the result
instead.

How should this be wired up after your patch?

Rob