Re: [PATCH 1/3] mdio-uclass.c: support fixed-link subnodes

Hello Rasmus,

Am 05.10.2020 um 15:15 schrieb Rasmus Villemoes:

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 rasmus.villemoes@prevas.dk

net/mdio-uclass.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/net/mdio-uclass.c b/net/mdio-uclass.c index 66ee2e1976..2f932b77df 100644 --- a/net/mdio-uclass.c +++ b/net/mdio-uclass.c @@ -139,6 +139,12 @@ static struct phy_device *dm_eth_connect_phy_handle(struct udevice *ethdev, struct ofnode_phandle_args phandle = {.node = ofnode_null()}; int i;

• if (CONFIG_IS_ENABLED(PHY_FIXED) &&

•    ofnode_valid(dev_read_subnode(ethdev, "fixed-link"))) {
  

• phy = phy_connect(NULL, -1, ethdev, interface);
  

• goto out;
  

• }
• for (i = 0; i < PHY_HANDLE_STR_CNT; i++) if (!dev_read_phandle_with_args(ethdev, phy_handle_str[i], NULL, 0, 0, &phandle))

@@ -168,6 +174,7 @@ static struct phy_device *dm_eth_connect_phy_handle(struct udevice *ethdev,

phy = dm_mdio_phy_connect(mdiodev, phy_addr, ethdev, interface);

+out: if (phy) phy->node = phandle.node;

Looks good to me... but I am not an expert in net subsystem... nevertheless:

Reviewed-by: Heiko Schocher hs@denx.de

bye, Heiko