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

[James Clark <james.clark@linaro.org>]

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