Subject: Re: [PATCH RFC net-next 02/10] net: stmmac: rename dev_id to userver

From: "Russell King (Oracle)" <[email-masked]>
Date: Fri, 10 Apr 2026 09:39:50 +0100

On Thu, Apr 09, 2026 at 04:07:42PM -0700, Jitendra Vegiraju wrote:
> Hi Russell,
> 
> On Wed, Apr 8, 2026 at 2:27 AM Russell King (Oracle)
> <[email-masked]> wrote:
> >
> > The Synopsys Databook and several implementation TRMs identify bits
> > 15:8 of the version register in dwmac v3.xx and v4.xx as "userver".
> > We even print its value with "User ID". Rather than using "dev_id",
> > use "userver" instead.
> >
> > Signed-off-by: Russell King (Oracle) <[email-masked]>
> > ---
> >  drivers/net/ethernet/stmicro/stmmac/hwif.c | 18 +++++++++---------
> >  1 file changed, 9 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.c b/drivers/net/ethernet/stmicro/stmmac/hwif.c
> > index 3774af66db48..830ff816ab4f 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/hwif.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/hwif.c
> > @@ -15,7 +15,7 @@
> >
> >  struct stmmac_version {
> >         u8 snpsver;
> > -       u8 dev_id;
> > +       u8 userver;
> >  };
> From the XGMAC databook that I have access to bits(15:8) identify the
> DEVID field of MAC_version register.
> The userver field is from bits(23:16) of the same register. This is a
> customer defined field (configured with coreConsultant).
> Currently stmmac doesn't care about bits(23:16).

Thanks for the additional information.

I don't have any XGMAC documentation, but this indicates that it differs
between XGMAC and previous cores - GMAC and GMAC4 cores, 15:8 are
documented as userver, and 31:16 are marked as reserved.

Note that the dev_info() also prints 15:8 as "User ID" not "Device ID".

To confirm, is the XGMAC version register at offset 0x20 ? Later GMAC
cores moved it to 0x110.

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