[PATCH v4 net-next 13/14] net: enetc: add loopback support for i.MX95 ENETC PF

[Wei Fang <wei.fang@nxp.com>]

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>
---
 .../net/ethernet/freescale/enetc/enetc4_pf.c   | 18 ++++++++++++++++++
 .../ethernet/freescale/enetc/enetc_pf_common.c |  4 +---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
index 4abbbbef00ff..c169900ccb4a 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
@@ -108,6 +108,21 @@ static void enetc4_pf_set_si_vlan_hash_filter(struct enetc_hw *hw,
 	enetc_port_wr(hw, ENETC4_PSIVHFR1(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_destroy_mac_list(struct enetc_pf *pf)
 {
 	struct enetc_mac_list_entry *entry;
@@ -714,6 +729,9 @@ 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 3f7ccc482301..0a2b8769a175 100644
--- 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 |
-- 
2.34.1