Re: [PATCH v9 1/7] firmware: smccc: Add an Arm SMCCC bus

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Sep 03, 2026 at 08:05:40PM +0530, Aneesh Kumar K.V wrote:
> Jason Gunthorpe <jgg@nvidia.com> writes:
> 
> > On Thu, Sep 03, 2026 at 02:22:51PM +0530, Aneesh Kumar K.V wrote:
> >
> >> I have updated the bus to match devices using func_id.
> >
> > Did you have any thoughts on how to handle ARM's versioning scheme
> > too?
> >
> > I'm not sure what the rules are but it seems like if the major changes
> > then the API is incompatible? So shouldn't every driver advertise a
> > supported major, and the major be in the modalias and checked by match
> > too?
> 
> I expect a single driver to handle the RSI features and determine the
> version range it supports. I don't think we want multiple drivers, each
> handling a different major version of the RMM release. 

I thought the plan was we are only going to support RMM V2 and there
will, never, ever be a V3. :) So RMM is maybe a bit different..

> Given that, wouldn't it be sufficient for the driver's probe routine
> to check the supported version range and return -ENODEV if it is
> unsupported?

It is sufficient, but is that what you want? Every driver needs to
manually check these version things, do they? Do we want this
duplication? Missing a check means FW upgrades might become Linux
breaking.

Jason