net: enetc: add loopback support for i.MX95 ENETC PF

Add internal loopback support for i.MX95 ENETC PF, the default loopback
mode is MAC level loopback, the MAC Tx data is looped back onto the Rx.
The MAC interface runs at a fixed 1:8 ratio of NETC clock in MAC-level
loopback mode, with no dependency on Tx clock.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20250506080735.3444381-15-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
index 1f6500f..c16378e 100644 (file)
--- a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
@@ -101,6 +101,21 @@ static void enetc4_pf_set_si_mc_hash_filter(struct enetc_hw *hw, int si,
        enetc_port_wr(hw, ENETC4_PSIMMHFR1(si), upper_32_bits(hash));
 }
 
+static void enetc4_pf_set_loopback(struct net_device *ndev, bool en)
+{
+       struct enetc_ndev_priv *priv = netdev_priv(ndev);
+       struct enetc_si *si = priv->si;
+       u32 val;
+
+       val = enetc_port_mac_rd(si, ENETC4_PM_CMD_CFG(0));
+       val = u32_replace_bits(val, en ? 1 : 0, PM_CMD_CFG_LOOP_EN);
+       /* Default to select MAC level loopback mode if loopback is enabled. */
+       val = u32_replace_bits(val, en ? LPBCK_MODE_MAC_LEVEL : 0,
+                              PM_CMD_CFG_LPBK_MODE);
+
+       enetc_port_mac_wr(si, ENETC4_PM_CMD_CFG(0), val);
+}
+
 static void enetc4_pf_clear_maft_entries(struct enetc_pf *pf)
 {
        int i;
@@ -536,6 +551,9 @@ static int enetc4_pf_set_features(struct net_device *ndev,
                enetc4_pf_set_si_vlan_promisc(hw, 0, promisc_en);
        }
 
+       if (changed & NETIF_F_LOOPBACK)
+               enetc4_pf_set_loopback(ndev, !!(features & NETIF_F_LOOPBACK));
+
        enetc_set_features(ndev, features);
 
        return 0;

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c b/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
index 8c563e5..edf14a9 100644 (file)
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
@@ -134,10 +134,8 @@ void enetc_pf_netdev_setup(struct enetc_si *si, struct net_device *ndev,
        }
 
        /* TODO: currently, i.MX95 ENETC driver does not support advanced features */
-       if (!is_enetc_rev1(si)) {
-               ndev->hw_features &= ~NETIF_F_LOOPBACK;
+       if (!is_enetc_rev1(si))
                goto end;
-       }
 
        ndev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
                             NETDEV_XDP_ACT_NDO_XMIT | NETDEV_XDP_ACT_RX_SG |