linux-kernel - Re: [PATCH v2 03/17] firmware: arm_scmi: Allow protocols to register for notifications

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Message-ID: <aW5Sh1lIS0n_2Fyr@pluto>
Date: Mon, 19 Jan 2026 15:49:27 +0000
From: Cristian Marussi <cristian.marussi@....com>
To: Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: Cristian Marussi <cristian.marussi@....com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	arm-scmi@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	sudeep.holla@....com, james.quinlan@...adcom.com,
	f.fainelli@...il.com, vincent.guittot@...aro.org,
	etienne.carriere@...com, peng.fan@....nxp.com, michal.simek@....com,
	dan.carpenter@...aro.org, d-gole@...com, elif.topuz@....com,
	lukasz.luba@....com, philip.radford@....com,
	souvik.chakravarty@....com
Subject: Re: [PATCH v2 03/17] firmware: arm_scmi: Allow protocols to register
 for notifications

On Mon, Jan 19, 2026 at 11:33:26AM +0000, Jonathan Cameron wrote:
> On Wed, 14 Jan 2026 11:46:07 +0000
> Cristian Marussi <cristian.marussi@....com> wrote:
> 
> > Allow protocols themselves to register for their own notifications and
> 
> and provide their own notifier callbacks.
> 
> > providing their own notifier callbacks. While at that, allow for a protocol
> > to register events with compilation-time unknown report/event sizes: such
> > events will use the maximum transport size.
> 
> I'm not keen on the 'while at that' part of the patch. In an ideal
> world that's a separate patch.

Yes indeed...it was tempting to do it together with the rework since it
was the only usecase that triggered the 'while-at' change...

...but this series in general needs more splitting both at the protocol
level and at the FS level (once I get some feedback from FS guys) so I
will split this out too.

> 
> One other comment inline.
> 
> Jonathan
> p.s. You get to my review victim whilst I run a particularly annoying
> bisection on the other screen (completely unrelated!) :)
> 
> > 
> > Signed-off-by: Cristian Marussi <cristian.marussi@....com>
> > ---
> > v1-->v2
> >  - Fixed multiline comment format
> > ---
> >  drivers/firmware/arm_scmi/common.h    |  4 ++++
> >  drivers/firmware/arm_scmi/driver.c    | 12 ++++++++++++
> >  drivers/firmware/arm_scmi/notify.c    | 28 ++++++++++++++++++++-------
> >  drivers/firmware/arm_scmi/notify.h    |  8 ++++++--
> >  drivers/firmware/arm_scmi/protocols.h |  6 ++++++
> >  5 files changed, 49 insertions(+), 9 deletions(-)
> > 
> 
> 
> > diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
> > index 78e9e27dc9ec..e84b4dbefe82 100644
> > --- a/drivers/firmware/arm_scmi/notify.c
> > +++ b/drivers/firmware/arm_scmi/notify.c
> 
> 
> > @@ -779,8 +787,13 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id,
> >  	}
> >  
> >  	evt = ee->evts;
> > -	for (i = 0; i < ee->num_events; i++)
> > +	for (i = 0; i < ee->num_events; i++) {
> > +		if (evt[i].max_payld_sz == 0) {
> > +			payld_sz = max_msg_sz;
> > +			break;
> > +		}
> >  		payld_sz = max_t(size_t, payld_sz, evt[i].max_payld_sz);
> 
> Everything here seems to already be a size_t.  It is rare that we actually need max_t over
> max, and definitely not when all the types match.
> 		payld_sz = max(payl_sz, evt[i].max_payld_sz);

...indeed...I will fix.

Thanks,
Cristian