[PATCH] net: ftgmac100: Support phyless operation

From: William A. Kennington III
Date: Wed Feb 17 2021 - 22:42:09 EST


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 <wak@xxxxxxxxxx>
---
.../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;

--
2.30.0.478.g8a0d178c01-goog