Re: [PATCH] dma-mapping: Stub out dma_{alloc,free,map}_pages() API

[James Clark]

On 16/06/2025 2:14 pm, James Clark wrote:
> On 16/06/2025 2:13 pm, Christoph Hellwig wrote:
> > On Mon, Jun 16, 2025 at 02:10:40PM +0100, James Clark wrote:
> > > The change introduces consistency with the existing declarations in
> > > dma-mapping.h. Surely there is value in consistency and it doesn't do 
> > > any
> > > harm to define new ones with stubs the same as the other ones. That way
> > > when you change an existing device that has DMA stuff to use a new 
> > > part of
> > > the API you don't have to predict that it will behave differently to
> > > another part of the API.
> >
> > Well, redoing the rest would definitively be nice, but so far no one
> > has signed up to that.
> >
> > > I suppose it is possible to #ifdef out the DMA stuff in this driver, but
> > > IMO it would be quite messy, and I don't think randomly not stubbing out
> > > some functions is the right way to move towards fixing all the 
> > > dependencies
> > > in all drivers. We should continue with the stubs for now and fix whole
> > > drivers one by one as a proper effort.
> >
> > Does the driver even work at all without DMA support?
>
> Yes it does, it has a few modes that don't require it. Presumably we 
> can't just add a depends into the kconfig for all devices because they 
> might not be using DMA.

*for all the different variants of spi-fsl-dpsi devices I mean