[PATCH 6/6] drivers: net: fsl_enetc: force the RGMII MAC speed/duplex instead of using in-band signaling

[Vladimir Oltean]

The same considerations apply to U-Boot as to Linux:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=c76a97218dcbb2cb7cec1404ace43ef96c87d874

This change is needed in order for enetc to be able to operate in RGMII
fixed-link mode.

Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
---
 drivers/net/fsl_enetc.c | 44 ++++++++++++++++++++++++++++++-----------
 drivers/net/fsl_enetc.h |  5 +++++
 2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/drivers/net/fsl_enetc.c b/drivers/net/fsl_enetc.c
index 5961775024ff..de1e42f907e7 100644
--- a/drivers/net/fsl_enetc.c
+++ b/drivers/net/fsl_enetc.c
@@ -178,21 +178,43 @@ static int enetc_init_sgmii(struct udevice *dev)
 }
 
 /* set up MAC for RGMII */
-static int enetc_init_rgmii(struct udevice *dev)
+static void enetc_init_rgmii(struct udevice *dev, struct phy_device *phydev)
 {
 	struct enetc_priv *priv = dev_get_priv(dev);
-	u32 if_mode;
+	u32 old_val, val;
 
-	/* enable RGMII AN */
-	if_mode = enetc_read_port(priv, ENETC_PM_IF_MODE);
-	if_mode |= ENETC_PM_IF_MODE_AN_ENA;
-	enetc_write_port(priv, ENETC_PM_IF_MODE, if_mode);
+	old_val = val = enetc_read_port(priv, ENETC_PM_IF_MODE);
 
-	return 0;
+	/* disable unreliable RGMII in-band signaling and force the MAC into
+	 * the speed negotiated by the PHY.
+	 */
+	val &= ~ENETC_PM_IF_MODE_AN_ENA;
+
+	if (phydev->speed == SPEED_1000) {
+		val &= ~ENETC_PM_IFM_SSP_MASK;
+		val |= ENETC_PM_IFM_SSP_1000;
+	} else if (phydev->speed == SPEED_100) {
+		val &= ~ENETC_PM_IFM_SSP_MASK;
+		val |= ENETC_PM_IFM_SSP_100;
+	} else if (phydev->speed == SPEED_10) {
+		val &= ~ENETC_PM_IFM_SSP_MASK;
+		val |= ENETC_PM_IFM_SSP_10;
+	}
+
+	if (phydev->duplex == DUPLEX_FULL)
+		val |= ENETC_PM_IFM_FULL_DPX;
+	else
+		val &= ~ENETC_PM_IFM_FULL_DPX;
+
+	if (val == old_val)
+		return;
+
+	enetc_write_port(priv, ENETC_PM_IF_MODE, val);
 }
 
 /* set up MAC configuration for the given interface type */
-static void enetc_setup_mac_iface(struct udevice *dev)
+static void enetc_setup_mac_iface(struct udevice *dev,
+				  struct phy_device *phydev)
 {
 	struct enetc_priv *priv = dev_get_priv(dev);
 	u32 if_mode;
@@ -202,7 +224,7 @@ static void enetc_setup_mac_iface(struct udevice *dev)
 	case PHY_INTERFACE_MODE_RGMII_ID:
 	case PHY_INTERFACE_MODE_RGMII_RXID:
 	case PHY_INTERFACE_MODE_RGMII_TXID:
-		enetc_init_rgmii(dev);
+		enetc_init_rgmii(dev, phydev);
 		break;
 	case PHY_INTERFACE_MODE_XGMII:
 	case PHY_INTERFACE_MODE_USXGMII:
@@ -546,10 +568,10 @@ static int enetc_start(struct udevice *dev)
 	enetc_setup_tx_bdr(dev);
 	enetc_setup_rx_bdr(dev);
 
-	enetc_setup_mac_iface(dev);
-
 	phy_startup(priv->phy);
 
+	enetc_setup_mac_iface(dev, priv->phy);
+
 	return 0;
 }
 
diff --git a/drivers/net/fsl_enetc.h b/drivers/net/fsl_enetc.h
index 110c1d78fbc6..a4409505e043 100644
--- a/drivers/net/fsl_enetc.h
+++ b/drivers/net/fsl_enetc.h
@@ -77,6 +77,11 @@ enum enetc_bdr_type {TX, RX};
 #define ENETC_PM_IF_MODE		0x8300
 #define  ENETC_PM_IF_MODE_RG		BIT(2)
 #define  ENETC_PM_IF_MODE_AN_ENA	BIT(15)
+#define  ENETC_PM_IFM_SSP_MASK		GENMASK(14, 13)
+#define  ENETC_PM_IFM_SSP_1000		(2 << 13)
+#define  ENETC_PM_IFM_SSP_100		(0 << 13)
+#define  ENETC_PM_IFM_SSP_10		(1 << 13)
+#define  ENETC_PM_IFM_FULL_DPX		BIT(12)
 #define  ENETC_PM_IF_IFMODE_MASK	GENMASK(1, 0)
 
 /* buffer descriptors count must be multiple of 8 and aligned to 128 bytes */
-- 
2.25.1