[PATCH] net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode

[PATCH] net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode

[Robert Hancock]

Update the axienet driver to properly support the Xilinx PCS/PMA PHY
component which is used for 1000BaseX and SGMII modes, including
properly configuring the auto-negotiation mode of the PHY and reading
the negotiated state from the PHY.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
---
 drivers/net/ethernet/xilinx/xilinx_axienet.h  |   3 +
 .../net/ethernet/xilinx/xilinx_axienet_main.c | 104 +++++++++++++-----
 2 files changed, 81 insertions(+), 26 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index f34c7903ff52..7326ad4d5e1c 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -419,6 +419,9 @@ struct axienet_local {
 	struct phylink *phylink;
 	struct phylink_config phylink_config;
 
+	/* Reference to PCS/PMA PHY if used */
+	struct mdio_device *pcs_phy;
+
 	/* Clock for AXI bus */
 	struct clk *clk;
 
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 9aafd3ecdaa4..895c2c7a7f03 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -1517,10 +1517,29 @@ static void axienet_validate(struct phylink_config *config,
 
 	phylink_set(mask, Asym_Pause);
 	phylink_set(mask, Pause);
-	phylink_set(mask, 1000baseX_Full);
-	phylink_set(mask, 10baseT_Full);
-	phylink_set(mask, 100baseT_Full);
-	phylink_set(mask, 1000baseT_Full);
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_NA:
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_GMII:
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		phylink_set(mask, 1000baseX_Full);
+		phylink_set(mask, 1000baseT_Full);
+		if (state->interface == PHY_INTERFACE_MODE_1000BASEX)
+			break;
+		phylink_set(mask, 100baseT_Full);
+		phylink_set(mask, 10baseT_Full);
+		break;
+	case PHY_INTERFACE_MODE_MII:
+		phylink_set(mask, 100baseT_Full);
+		phylink_set(mask, 10baseT_Full);
+	default:
+		break;
+	}
 
 	bitmap_and(supported, supported, mask,
 		   __ETHTOOL_LINK_MODE_MASK_NBITS);
@@ -1533,38 +1552,54 @@ static void axienet_mac_pcs_get_state(struct phylink_config *config,
 {
 	struct net_device *ndev = to_net_dev(config->dev);
 	struct axienet_local *lp = netdev_priv(ndev);
-	u32 emmc_reg, fcc_reg;
-
-	state->interface = lp->phy_mode;
 
-	emmc_reg = axienet_ior(lp, XAE_EMMC_OFFSET);
-	if (emmc_reg & XAE_EMMC_LINKSPD_1000)
-		state->speed = SPEED_1000;
-	else if (emmc_reg & XAE_EMMC_LINKSPD_100)
-		state->speed = SPEED_100;
-	else
-		state->speed = SPEED_10;
-
-	state->pause = 0;
-	fcc_reg = axienet_ior(lp, XAE_FCC_OFFSET);
-	if (fcc_reg & XAE_FCC_FCTX_MASK)
-		state->pause |= MLO_PAUSE_TX;
-	if (fcc_reg & XAE_FCC_FCRX_MASK)
-		state->pause |= MLO_PAUSE_RX;
-
-	state->an_complete = 0;
-	state->duplex = 1;
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+		phylink_mii_c22_pcs_get_state(lp->pcs_phy, state);
+		break;
+	default:
+		break;
+	}
 }
 
 static void axienet_mac_an_restart(struct phylink_config *config)
 {
-	/* Unsupported, do nothing */
+	struct net_device *ndev = to_net_dev(config->dev);
+	struct axienet_local *lp = netdev_priv(ndev);
+
+	phylink_mii_c22_pcs_an_restart(lp->pcs_phy);
 }
 
 static void axienet_mac_config(struct phylink_config *config, unsigned int mode,
 			       const struct phylink_link_state *state)
 {
-	/* nothing meaningful to do */
+	struct net_device *ndev = to_net_dev(config->dev);
+	struct axienet_local *lp = netdev_priv(ndev);
+	int ret;
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+		ret = phylink_mii_c22_pcs_config(lp->pcs_phy, mode,
+						 state->interface,
+						 state->advertising);
+		if (ret < 0)
+			netdev_warn(ndev, "Failed to configure PCS: %d\n",
+				    ret);
+
+		/* Ensure isolate bit is cleared */
+		ret = mdiobus_modify(lp->pcs_phy->bus, lp->pcs_phy->addr,
+				     MII_BMCR, BMCR_ISOLATE, 0);
+		if (ret < 0)
+			netdev_warn(ndev, "Failed to disable ISOLATE: %d\n",
+				    ret);
+
+		break;
+
+	default:
+		break;
+	}
 }
 
 static void axienet_mac_link_down(struct phylink_config *config,
@@ -1999,6 +2034,20 @@ static int axienet_probe(struct platform_device *pdev)
 			dev_warn(&pdev->dev,
 				 "error registering MDIO bus: %d\n", ret);
 	}
+	if (lp->phy_mode == PHY_INTERFACE_MODE_SGMII ||
+	    lp->phy_mode == PHY_INTERFACE_MODE_1000BASEX) {
+		if (!lp->phy_node) {
+			dev_err(&pdev->dev, "phy-handle required for 1000BaseX/SGMII\n");
+			ret = -EINVAL;
+			goto free_netdev;
+		}
+		lp->pcs_phy = of_mdio_find_device(lp->phy_node);
+		if (!lp->pcs_phy) {
+			ret = -EPROBE_DEFER;
+			goto free_netdev;
+		}
+		lp->phylink_config.pcs_poll = true;
+	}
 
 	lp->phylink_config.dev = &ndev->dev;
 	lp->phylink_config.type = PHYLINK_NETDEV;
@@ -2036,6 +2085,9 @@ static int axienet_remove(struct platform_device *pdev)
 	if (lp->phylink)
 		phylink_destroy(lp->phylink);
 
+	if (lp->pcs_phy)
+		put_device(&lp->pcs_phy->dev);
+
 	axienet_mdio_teardown(lp);
 
 	clk_disable_unprepare(lp->clk);
-- 
2.18.4

Re: [PATCH] net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode

[Andrew Lunn]

>  static void axienet_mac_config(struct phylink_config *config, unsigned int mode,
>  			       const struct phylink_link_state *state)
>  {
> -	/* nothing meaningful to do */
> +	struct net_device *ndev = to_net_dev(config->dev);
> +	struct axienet_local *lp = netdev_priv(ndev);
> +	int ret;
> +
> +	switch (state->interface) {
> +	case PHY_INTERFACE_MODE_SGMII:
> +	case PHY_INTERFACE_MODE_1000BASEX:
> +		ret = phylink_mii_c22_pcs_config(lp->pcs_phy, mode,
> +						 state->interface,
> +						 state->advertising);
> +		if (ret < 0)
> +			netdev_warn(ndev, "Failed to configure PCS: %d\n",
> +				    ret);
> +
> +		/* Ensure isolate bit is cleared */
> +		ret = mdiobus_modify(lp->pcs_phy->bus, lp->pcs_phy->addr,
> +				     MII_BMCR, BMCR_ISOLATE, 0);

Hi Robert

That looks like a layering violation. Maybe move this into
phylink_mii_c22_pcs_config(), it is accessing MII_BMCR anyway.

      Andrew

Re: [PATCH] net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode

[Robert Hancock]

On Mon, 2020-10-19 at 23:36 +0200, Andrew Lunn wrote:
> >  static void axienet_mac_config(struct phylink_config *config,
> > unsigned int mode,
> >  			       const struct phylink_link_state *state)
> >  {
> > -	/* nothing meaningful to do */
> > +	struct net_device *ndev = to_net_dev(config->dev);
> > +	struct axienet_local *lp = netdev_priv(ndev);
> > +	int ret;
> > +
> > +	switch (state->interface) {
> > +	case PHY_INTERFACE_MODE_SGMII:
> > +	case PHY_INTERFACE_MODE_1000BASEX:
> > +		ret = phylink_mii_c22_pcs_config(lp->pcs_phy, mode,
> > +						 state->interface,
> > +						 state->advertising);
> > +		if (ret < 0)
> > +			netdev_warn(ndev, "Failed to configure PCS:
> > %d\n",
> > +				    ret);
> > +
> > +		/* Ensure isolate bit is cleared */
> > +		ret = mdiobus_modify(lp->pcs_phy->bus, lp->pcs_phy-
> > >addr,
> > +				     MII_BMCR, BMCR_ISOLATE, 0);
> 
> Hi Robert
> 
> That looks like a layering violation. Maybe move this into
> phylink_mii_c22_pcs_config(), it is accessing MII_BMCR anyway.

Could do - do we think there's any harm in just disabling BMCR_ISOLATE
in all cases in that function?

-- 
Robert Hancock
Senior Hardware Designer, Advanced Technologies 
www.calian.com

Re: [PATCH] net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode

[Andrew Lunn]

> > Hi Robert
> > 
> > That looks like a layering violation. Maybe move this into
> > phylink_mii_c22_pcs_config(), it is accessing MII_BMCR anyway.
> 
> Could do - do we think there's any harm in just disabling BMCR_ISOLATE
> in all cases in that function?

We have something similar in phylib:

/**
 * genphy_restart_aneg - Enable and Restart Autonegotiation
 * @phydev: target phy_device struct
 */
int genphy_restart_aneg(struct phy_device *phydev)
{
        /* Don't isolate the PHY if we're negotiating */
        return phy_modify(phydev, MII_BMCR, BMCR_ISOLATE,
                          BMCR_ANENABLE | BMCR_ANRESTART);
}

so i think it would also be safe in PCS code.

   Andrew