On Mon, Aug 09, 2021 at 03:20:57AM +0000, Joel Stanley wrote:
> On Sat, 7 Aug 2021 at 19:19, Andrew Lunn <andrew@xxxxxxx> wrote:
> >
> > > +static void liteeth_reset_hw(struct liteeth *priv)
> > > +{
> > > + /* Reset, twice */
> > > + writeb(0, priv->base + LITEETH_PHY_CRG_RESET);
> > > + udelay(10);
> > > + writeb(1, priv->base + LITEETH_PHY_CRG_RESET);
> > > + udelay(10);
> > > + writeb(0, priv->base + LITEETH_PHY_CRG_RESET);
> > > + udelay(10);
> >
> > What is this actually resetting?
>
> This comes from the reference firmware that many (but not all) litex
> systems run before loading their operating system.
>
> I'm not completely sure how necessary it still is; I will drop it for now.
Which did not answer my question. Once we know what is being reset, we
can maybe suggest when/how it should be reset.
> > > +static int liteeth_probe(struct platform_device *pdev)
> > > +{
> > > + struct net_device *netdev;
> > > + void __iomem *buf_base;
> > > + struct resource *res;
> > > + struct liteeth *priv;
> > > + int irq, err;
> > > +
> > > + netdev = alloc_etherdev(sizeof(*priv));
> > > + if (!netdev)
> > > + return -ENOMEM;
> > > +
> > > + priv = netdev_priv(netdev);
> > > + priv->netdev = netdev;
> > > + priv->dev = &pdev->dev;
> > > +
> > > + irq = platform_get_irq(pdev, 0);
> > > + if (irq < 0) {
> > > + dev_err(&pdev->dev, "Failed to get IRQ\n");
> > > + goto err;
> > > + }
> > > +
> > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > + priv->base = devm_ioremap_resource(&pdev->dev, res);
> > > + if (IS_ERR(priv->base)) {
> > > + err = PTR_ERR(priv->base);
> > > + goto err;
> > > + }
> > > +
> > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> > > + priv->mdio_base = devm_ioremap_resource(&pdev->dev, res);
> > > + if (IS_ERR(priv->mdio_base)) {
> > > + err = PTR_ERR(priv->mdio_base);
> > > + goto err;
> > > + }
> >
> > So you don't have any PHY handling, or any MDIO bus master code. So i
> > would drop this, until the MDIO architecture question is answered. I
> > also wonder how much use the MAC driver is without any PHY code?
> > Unless you have a good reason, i don't think we should merge this
> > until it makes the needed calls into phylib. It is not much code to
> > add.
>
> You mean I should skip out the parsing of the mdio base until I'm
> using it? That's reasonable.
It could be we insist you add MDIO and PHY handling. But first we need
to understand the architecture.
Andrew
