On 2/17/2021 7:40 PM, William A. Kennington III wrote:
> We have BMC to BMC connections that lack a PHY in between but don't
> want to use the NC-SI state machinery of the kernel. Instead,
> allow for an option to disable the phy detection and mdio logic.
>
> Signed-off-by: William A. Kennington III <w...@google.com>
The way drivers deal with MAC to MAC connection is to use a fixed-link
Device Tree node that just presents hard coded link parameters. This
provides an emulation for the PHY library as well as user-space and
requires little Ethernet MAC driver changes other than doing something
along these lines:
/* Fetch the PHY phandle */
priv->phy_dn = of_parse_phandle(dn, "phy-handle", 0);
/* In the case of a fixed PHY, the DT node associated
* to the PHY is the Ethernet MAC DT node.
*/
if (!priv->phy_dn && of_phy_is_fixed_link(dn)) {
ret = of_phy_register_fixed_link(dn);
if (ret)
return ret;
priv->phy_dn = of_node_get(dn);
}
Can this work for you here?
> ---
> .../devicetree/bindings/net/ftgmac100.txt | 2 ++
> drivers/net/ethernet/faraday/ftgmac100.c | 30 +++++++++++--------
> 2 files changed, 19 insertions(+), 13 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/ftgmac100.txt
> b/Documentation/devicetree/bindings/net/ftgmac100.txt
> index 29234021f601..22c729c5fd3e 100644
> --- a/Documentation/devicetree/bindings/net/ftgmac100.txt
> +++ b/Documentation/devicetree/bindings/net/ftgmac100.txt
> @@ -19,6 +19,8 @@ Optional properties:
> - phy-mode: See ethernet.txt file in the same directory. If the property is
> absent, "rgmii" is assumed. Supported values are "rgmii*" and "rmii" for
> aspeed parts. Other (unknown) parts will accept any value.
> +- no-phy: Disable any MDIO or PHY connection logic and assume the interface
> + is always up.
> - use-ncsi: Use the NC-SI stack instead of an MDIO PHY. Currently assumes
> rmii (100bT) but kept as a separate property in case NC-SI grows support
> for a gigabit link.
> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c
> b/drivers/net/ethernet/faraday/ftgmac100.c
> index 88bfe2107938..f2cf190654c8 100644
> --- a/drivers/net/ethernet/faraday/ftgmac100.c
> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> @@ -1467,18 +1467,18 @@ static int ftgmac100_open(struct net_device *netdev)
> return err;
> }
>
> - /* When using NC-SI we force the speed to 100Mbit/s full duplex,
> + /* When PHYless we force the speed to 100Mbit/s full duplex,
> *
> * Otherwise we leave it set to 0 (no link), the link
> * message from the PHY layer will handle setting it up to
> * something else if needed.
> */
> - if (priv->use_ncsi) {
> - priv->cur_duplex = DUPLEX_FULL;
> - priv->cur_speed = SPEED_100;
> - } else {
> + if (netdev->phydev) {
> priv->cur_duplex = 0;
> priv->cur_speed = 0;
> + } else {
> + priv->cur_duplex = DUPLEX_FULL;
> + priv->cur_speed = SPEED_100;
> }
>
> /* Reset the hardware */
> @@ -1506,14 +1506,16 @@ static int ftgmac100_open(struct net_device *netdev)
> if (netdev->phydev) {
> /* If we have a PHY, start polling */
> phy_start(netdev->phydev);
> - } else if (priv->use_ncsi) {
> - /* If using NC-SI, set our carrier on and start the stack */
> + } else {
> + /* If PHYless, set our carrier on and start the stack */
> netif_carrier_on(netdev);
>
> - /* Start the NCSI device */
> - err = ncsi_start_dev(priv->ndev);
> - if (err)
> - goto err_ncsi;
> + if (priv->use_ncsi) {
> + /* Start the NCSI device */
> + err = ncsi_start_dev(priv->ndev);
> + if (err)
> + goto err_ncsi;
> + }
> }
>
> return 0;
> @@ -1725,8 +1727,8 @@ static int ftgmac100_setup_clk(struct ftgmac100 *priv)
> * 1000Mbit link speeds. As NCSI is limited to 100Mbit, 25MHz
> * is sufficient
> */
> - rc = clk_set_rate(priv->clk, priv->use_ncsi ? FTGMAC_25MHZ :
> - FTGMAC_100MHZ);
> + rc = clk_set_rate(priv->clk, priv->netdev->phydev ? FTGMAC_100MHZ :
> + FTGMAC_25MHZ);
> if (rc)
> goto cleanup_clk;
>
> @@ -1837,6 +1839,8 @@ static int ftgmac100_probe(struct platform_device *pdev)
> priv->ndev = ncsi_register_dev(netdev, ftgmac100_ncsi_handler);
> if (!priv->ndev)
> goto err_phy_connect;
> + } else if (np && of_get_property(np, "no-phy", NULL)) {
> + dev_info(&pdev->dev, "Using PHYless interface\n");
> } else if (np && of_get_property(np, "phy-handle", NULL)) {
> struct phy_device *phy;
>
>
--
Florian
