[PATCH v2 net-next 12/13] 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 65e6e3742ada..948d2f796bfb 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c
@@ -709,6 +709,21 @@ static void enetc4_pf_set_rx_mode(struct net_device *ndev)
 	queue_work(si->workqueue, &si->rx_mode_task);
 }
 
+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 int enetc4_pf_set_features(struct net_device *ndev,
 				  netdev_features_t features)
 {
@@ -722,6 +737,9 @@ 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