net: enetc: VFs do not support HWTSTAMP_TX_ONESTEP_SYNC

Actually ENETC VFs do not support HWTSTAMP_TX_ONESTEP_SYNC because only
ENETC PF can access PMa_SINGLE_STEP registers. And there will be a crash
if VFs are used to test one-step timestamp, the crash log as follows.

[  129.110909] Unable to handle kernel paging request at virtual address 00000000000080c0
[  129.287769] Call trace:
[  129.290219]  enetc_port_mac_wr+0x30/0xec (P)
[  129.294504]  enetc_start_xmit+0xda4/0xe74
[  129.298525]  enetc_xmit+0x70/0xec
[  129.301848]  dev_hard_start_xmit+0x98/0x118

Fixes: 4151473 ("enetc: add get_ts_info interface for ethtool")
Cc: [email protected]
Signed-off-by: Wei Fang <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Tested-by: Vladimir Oltean <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Wei Fang

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -3244,6 +3244,9 @@ static int enetc_hwtstamp_set(struct net_device *ndev, struct ifreq *ifr)
 		new_offloads |= ENETC_F_TX_TSTAMP;
 		break;
 	case HWTSTAMP_TX_ONESTEP_SYNC:
+		if (!enetc_si_is_pf(priv->si))
+			return -EOPNOTSUPP;
+
 		new_offloads &= ~ENETC_F_TX_TSTAMP_MASK;
 		new_offloads |= ENETC_F_TX_ONESTEP_SYNC_TSTAMP;
 		break;

drivers/net/ethernet/freescale/enetc/enetc_ethtool.c

@@ -832,6 +832,7 @@ static int enetc_set_coalesce(struct net_device *ndev,
 static int enetc_get_ts_info(struct net_device *ndev,
 			     struct kernel_ethtool_ts_info *info)
 {
+	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	int *phc_idx;
 
 	phc_idx = symbol_get(enetc_phc_index);
@@ -852,8 +853,10 @@ static int enetc_get_ts_info(struct net_device *ndev,
 				SOF_TIMESTAMPING_TX_SOFTWARE;
 
 	info->tx_types = (1 << HWTSTAMP_TX_OFF) |
-			 (1 << HWTSTAMP_TX_ON) |
-			 (1 << HWTSTAMP_TX_ONESTEP_SYNC);
+			 (1 << HWTSTAMP_TX_ON);
+
+	if (enetc_si_is_pf(priv->si))
+		info->tx_types |= (1 << HWTSTAMP_TX_ONESTEP_SYNC);
 
 	info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |
 			   (1 << HWTSTAMP_FILTER_ALL);