Re: [PATCH net-next] net: dsa: lantiq_gswip: Add support for dumping the registers

[Andrew Lunn]

On Tue, Apr 13, 2021 at 12:24:49AM +0200, Martin Blumenstingl wrote:
> Hi Andrew,
> 
> On Mon, Apr 12, 2021 at 1:16 AM Andrew Lunn <andrew@xxxxxxx> wrote:
> >
> > On Sun, Apr 11, 2021 at 10:55:11PM +0200, Martin Blumenstingl wrote:
> > > Add support for .get_regs_len and .get_regs so it is easier to find out
> > > about the state of the ports on the GSWIP hardware. For this we
> > > specifically add the GSWIP_MAC_PSTATp(port) and GSWIP_MDIO_STATp(port)
> > > register #defines as these contain the current port status (as well as
> > > the result of the auto polling mechanism). Other global and per-port
> > > registers which are also considered useful are included as well.
> >
> > Although this is O.K, there has been a trend towards using devlink
> > regions for this, and other register sets in the switch. Take a look
> > at drivers/net/dsa/mv88e6xxx/devlink.c.
> >
> > There is a userspace tool for the mv88e6xxx devlink regions here:
> >
> > https://github.com/lunn/mv88e6xxx_dump
> >
> > and a few people have forked it and modified it for other DSA
> > switches. At some point we might want to try to merge the forks back
> > together so we have one tool to dump any switch.
> actually I was wondering if there is some way to make the registers
> "easier to read" in userspace.

You can add decoding to ethtool. The marvell chips have this, to some
extent. But the ethtool API is limited to just port registers, and
there can be a lot more registers which are not associated to a
port. devlink gives you access to these additional registers.

      Andrew