Subject: Re: [RFC PATCH 2/2] arm64: mm: add SMCCC-backed cache invalidate provider

From: Catalin Marinas <[email-masked]>
Date: Thu, 21 May 2026 17:35:45 +0100

On Thu, May 21, 2026 at 12:18:12PM +0100, Jonathan Cameron wrote:
> On Thu, 21 May 2026 07:30:47 +0000
> Srirangan Madhavan <[email-masked]> wrote:
> >  MAINTAINERS                 |   1 +
> >  arch/arm64/mm/Makefile      |   1 +
> >  arch/arm64/mm/cache_maint.c | 180 ++++++++++++++++++++++++++++++++++++
> 
> File location wise, this is a driver for a subsystem, be it one closely
> coupled to arm.  Arm maintainers, do you want it in there or in drivers/cache ?
> My personal preference is always to keep drivers with subsystems but I don't
> care that much.

Yes, it makes more sense to keep it under drivers/cache/. We have many
other users of the SMCCC interface under drivers/.

> 
> >  3 files changed, 182 insertions(+)
> >  create mode 100644 arch/arm64/mm/cache_maint.c
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 2fb1c75afd16..33c35f8e6e40 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -25383,6 +25383,7 @@ M:	Jonathan Cameron <[email-masked]>
> >  S:	Maintained
> >  T:	git https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux.git/
> >  F:	Documentation/devicetree/bindings/cache/
> > +F:	arch/arm64/mm/cache_maint.c
> 
> I wonder if this should just have a separate maintainers entry? 
> We did that for the hisi driver.

Not needed if the code is moved to drivers/cache/.

> > +struct arm64_smccc_cache {
> > +	/* Must be first member */
> > +	struct cache_coherency_ops_inst cci;
> > +	struct mutex lock; /* Serializes SMCCC cache maintenance calls. */
> > +	u32 latency_us;
> > +	u32 rate_limit;
> > +	bool global_op;
> > +	u64 global_flush_gen;
> > +};
> > +
> > +static struct arm64_smccc_cache *arm64_smccc_cache;

Nit: if these are all static, does it still make sense to use the arm64_
prefix throughout this file?

-- 
Catalin