linux-kernel - Re: [PATCH v3 6/7] firmware: smccc: Add function to fetch SMCCC version

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Message-ID: <20200515125758.GC1591@bogus>
Date:   Fri, 15 May 2020 13:57:58 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Mark Rutland <mark.rutland@....com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Steven Price <steven.price@....com>,
        linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        harb@...erecomputing.com
Subject: Re: [PATCH v3 6/7] firmware: smccc: Add function to fetch SMCCC
 version

On Fri, May 15, 2020 at 01:08:11PM +0100, Mark Rutland wrote:
> On Wed, May 06, 2020 at 05:44:10PM +0100, Sudeep Holla wrote:
> > For backward compatibility reasons, PSCI maintains SMCCC version as
> > SMCCC didn't provide ARM_SMCCC_VERSION_FUNC_ID until v1.1
> > 
> > Let us provide accessors to fetch the SMCCC version in PSCI so that
> > other SMCCC v1.1+ features can use it.
> 
> Stale commit message? This was factored out of PSCI in the prior commit.
>

Duh ! Will drop that.

> > Reviewed-by: Steven Price <steven.price@....com>
> > Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> > ---
> >  drivers/firmware/smccc/smccc.c | 4 ++++
> >  include/linux/arm-smccc.h      | 9 +++++++++
> >  2 files changed, 13 insertions(+)
> > 
> > diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
> > index 488699aae24f..672974df0dfe 100644
> > --- a/drivers/firmware/smccc/smccc.c
> > +++ b/drivers/firmware/smccc/smccc.c
> > @@ -24,3 +24,7 @@ enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
> >  	return smccc_conduit;
> >  }
> >  
> > +u32 arm_smccc_version_get(void)
> > +{
> > +	return smccc_version;
> > +}
> 
> Could we please call this arm_smccc_get_version(), to align with the
> existing arm_smccc_1_1_get_conduit()?
>

Right will fix that. (I may suddenly got into SCMI mode where Greg or
someone asked me change all the function names to have verb at the end 😁)

> > diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> > index 11fb20bfa8f7..8dd54dad1ec5 100644
> > --- a/include/linux/arm-smccc.h
> > +++ b/include/linux/arm-smccc.h
> > @@ -109,6 +109,15 @@ void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit);
> >   */
> >  enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void);
> >  
> > +/**
> > + * arm_smccc_version_get()
> > + *
> > + * Returns the version to be used for SMCCCv1.1 or later.
> > + *
> > + * When SMCCCv1.1 or above is not present, assumes and returns SMCCCv1.0.
> > + */
> > +u32 arm_smccc_version_get(void);
> 
> Can we please reword the last line to something like:
>
> | When SMCCCv1.1 or above is not present, returns SMCCCv1.0, but this
> | does not imply the presence of firmware or a valid conduit. Callers
> | handling SMCCCv1.0 must determine the conduit by other means.
>

Sure

> With all that:
> 
> Acked-by: Mark Rutland <mark.rutland@....com>
> 

Thanks,

-- 
Regards,
Sudeep