On Mon, Oct 05, 2020 at 03:15:16PM +0200, Rasmus Villemoes wrote:
> When trying to port our mpc8309-based board to DM_ETH, on top of
> Heiko's patches, I found that nothing in mdio-uclass.c seems to
> support the use of a fixed-link subnode of the ethernet DT node. That
> is, the ethernet node looks like
>
> enet0: ethernet@2000 {
> device_type = "network";
> compatible = "ucc_geth";
> ...
> fixed-link {
> reg = <0xffffffff>;
> speed = <100>;
> full-duplex;
> };
>
> but the current code expects there to be phy-handle property. Adding
> that, i.e.
>
> phy-handle = <&enet0phy>;
> enet0phy: fixed-link {
>
> just makes the code break a few lines later since a fixed-link node
> doesn't have a reg property. Ignoring the dtc complaint and adding a
> dummy reg property, we of course hit "can't find MDIO bus for node
> ethernet@2000" since indeed, the parent node of the phy node does not
> represent an MDIO bus. So that's obviously the wrong path.
>
> Now, in linux, it seems that the fixed link case is treated specially;
> in the of_phy_get_and_connect() which roughly corresponds to
> dm_eth_connect_phy_handle() we have
>
> if (of_phy_is_fixed_link(np)) {
> ret = of_phy_register_fixed_link(np);
> ...
> } else {
> phy_np = of_parse_phandle(np, "phy-handle", 0);
> ...
> }
>
> phy = of_phy_connect(dev, phy_np, hndlr, 0, iface);
>
> And U-Boot's phy_connect() does have support for fixed-link
> subnodes. Calling phy_connect() directly with NULL bus and a dummy
> address does seem to make the ethernet work.
>
> Signed-off-by: Rasmus Villemoes <[email protected]>
> Reviewed-by: Heiko Schocher <[email protected]>Applied to u-boot/master, thanks! -- Tom
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