[PATCH v3 1/6] net: introduce DSA class for Ethernet switches

[Vladimir Oltean]

On Tue, 17 Dec 2019 at 09:18, Alexandru Marginean
<alexm.osslist at gmail.com> wrote:
>
> On 12/15/2019 2:08 PM, Vladimir Oltean wrote:
> > On Tue, 3 Dec 2019 at 17:32, Alex Marginean <alexandru.marginean at nxp.com> wrote:
> >> +/**
> >> + * This function deals with additional devices around the switch as these should
> >> + * have been bound to drivers by now.
> >> + * TODO: pick up references to other switch devices here, if we're cascaded.
> >> + */
> >> +static int dm_dsa_pre_probe(struct udevice *dev)
> >> +{
> >> +       struct dsa_perdev_platdata *platdata = dev_get_platdata(dev);
> >> +       int i;
> >> +
> >> +       if (!platdata)
> >> +               return -EINVAL;
> >> +
> >> +       if (ofnode_valid(platdata->master_node))
> >> +               uclass_find_device_by_ofnode(UCLASS_ETH, platdata->master_node,
> >> +                                            &platdata->master_dev);
> >> +
> >> +       for (i = 0; i < platdata->num_ports; i++) {
> >> +               struct dsa_port_platdata *port = &platdata->port[i];
> >> +
> >> +               if (port->dev) {
> >> +                       port->dev->priv = port;
> >> +                       port->phy = dm_eth_phy_connect(port->dev);
> >
> > Fixed-link interfaces don't work with DM_MDIO. That is somewhat
> > natural as there is no MDIO bus for a fixed-link. However the legacy
> > phy_connect function can be made rather easily to work with
> > fixed-link, since it has the necessary code for dealing with it
> > already. I am not, however, sure how it ever worked in the absence of
> > an MDIO bus.
> >
> > commit 1b7e23cc7e6d0dc3fe7ae9c55390b40717ff3c3a
> > Author: Vladimir Oltean <olteanv at gmail.com>
> > Date:   Sat Dec 14 23:25:40 2019 +0200
> >
> >      phy: make phy_connect_fixed work with a null mdio bus
> >
> >      It is utterly pointless to require an MDIO bus pointer for a fixed PHY
> >      device. The fixed.c implementation does not require it, only
> >      phy_device_create. Fix that.
> >
> >      Signed-off-by: Vladimir Oltean <olteanv at gmail.com>
> >
> > diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> > index 80a7664e4978..8ea5c9005291 100644
> > --- a/drivers/net/phy/phy.c
> > +++ b/drivers/net/phy/phy.c
> > @@ -658,7 +658,7 @@ static struct phy_device *phy_device_create(struct
> > mii_dev *bus, int addr,
> >          dev = malloc(sizeof(*dev));
> >          if (!dev) {
> >                  printf("Failed to allocate PHY device for %s:%d\n",
> > -                      bus->name, addr);
> > +                      bus ? bus->name : "(null bus)", addr);
> >                  return NULL;
> >          }
> >
> > @@ -686,7 +686,7 @@ static struct phy_device *phy_device_create(struct
> > mii_dev *bus, int addr,
> >                  return NULL;
> >          }
> >
> > -       if (addr >= 0 && addr < PHY_MAX_ADDR)
> > +       if (addr >= 0 && addr < PHY_MAX_ADDR && phy_id != PHY_FIXED_ID)
> >                  bus->phymap[addr] = dev;
> >
> >          return dev;
> >
> > With the patch above in place, fixed-link can also be made to work
> > with some logic similar to what can be seen below:
> >
> >      if (ofnode_valid(ofnode_find_subnode(port->dev->node, "fixed-link")))
> >          port->phy = phy_connect(NULL, 0, port->dev, phy_mode); //
> > phy_mode needs to be pre-parsed somewhere else as well
> >      else
> >          port->phy = dm_eth_phy_connect(port->dev);
> >
> > How would you see fixed-link interfaces being treated? My question so
> > far is in the context of front-panel ports but I am interested in your
> > view of the CPU port situation as well.
>
> I was thinking turning dm_eth_phy_connect into a more generic helper
> that also deals with fixed links, which it does not yet.  That would

How would you do that? Just put my snippet above in a higher-level
wrapper over dm_eth_phy_connect and phy_connect? Otherwise I think
it's pretty difficult and hacky to pass a null mdiodev pointer through
dm_mdio_phy_connect.

> move the "fixed-link" if out of the driver code.  Ideally the driver
> should be able to call a single helper and, if the device has a DT node,
> it would get back a PHY handle to either a proper PHY or to a fixed link
> (from phy_connect_fixed).
>
> Alex
>
> >
> >> +               }
> >> +       }
> >> +
> >> +       return 0;
> >> +}
> >
> > Thanks,
> > -Vladimir
> >