Hello Matt,
On Fri, Aug 09, 2019 at 06:20:28PM -0400, Matt Pelland wrote:
> On Fri, Aug 09, 2019 at 10:32:50AM +0200, Antoine Tenart wrote:
> > On Thu, Aug 08, 2019 at 07:06:06PM -0400, Matt Pelland wrote:
> > > @@ -5084,14 +5107,38 @@ static int mvpp2_port_probe(struct
> > > platform_device *pdev,
> > > goto err_free_netdev;
> > > }
> > >
> > > + port = netdev_priv(dev);
> > > +
> > > if (port_node) {
> > > - comphy = devm_of_phy_get(&pdev->dev, port_node, NULL);
> > > - if (IS_ERR(comphy)) {
> > > - if (PTR_ERR(comphy) == -EPROBE_DEFER) {
> > > - err = -EPROBE_DEFER;
> > > - goto err_free_netdev;
> > > + for (i = 0, ncomphys = 0; i < ARRAY_SIZE(port->comphys); i++) {
> > > + port->comphys[i] = devm_of_phy_get_by_index(&pdev->dev,
> > > + port_node,
> > > + i);
> > > + if (IS_ERR(port->comphys[i])) {
> > > + err = PTR_ERR(port->comphys[i]);
> > > + port->comphys[i] = NULL;
> > > + if (err == -EPROBE_DEFER)
> > > + goto err_free_netdev;
> > > + err = 0;
> > > + break;
> > > }
> > > - comphy = NULL;
> > > +
> > > + ++ncomphys;
> > > + }
> > > +
> > > + if (phy_mode == PHY_INTERFACE_MODE_XAUI)
> > > + nrequired_comphys = 4;
> > > + else if (phy_mode == PHY_INTERFACE_MODE_RXAUI)
> > > + nrequired_comphys = 2;
> > > + else
> > > + nrequired_comphys = 1;
> > > +
> > > + if (ncomphys < nrequired_comphys) {
> > > + dev_err(&pdev->dev,
> > > + "not enough comphys to support %s\n",
> > > + phy_modes(phy_mode));
> > > + err = -EINVAL;
> > > + goto err_free_netdev;
> >
> > The comphy is optional and could not be described (some SoC do not have
> > a driver for their comphy, and some aren't described at all). In such
> > cases we do rely on the bootloader/firmware configuration. Also, I'm not
> > sure how that would work with dynamic reconfiguration of the mode if the
> > n# of lanes used changes (I'm not sure that is possible though).
> >
>
> I'm new to this space, but, from my limited experience it seems unlikely that
> some hardware configuration would require dynamically reconfiguring the number
> of comphy lanes used depending on the phy mode. Unless you disagree, instead
> of
> removing this check or making things really complicated to support this
> scenario, I propose extending the conditional above to disable sanity checking
> if no comphys were parsed out of the device tree. Something like:
>
> if (ncomphys != 0 && ncomphys < nrequired_comphys)
>
> This would cover Maxime's request for sanity checking, which I think is
> valuable, while also maintaining compatibility with platforms that have no
> comphy drivers or some other issue that prevents properly defining comphy
> nodes
> in the device tree. Does that sound reasonable?
That sounds good.
Thanks!
Antoine
--
Antoine Ténart, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
