mlxsw: Send PTP packets as data packets to overcome a limitation

In Spectrum-2 and Spectrum-3, the correction field of PTP packets which are
sent as control packets is not updated at egress port. To overcome this
limitation, PTP packets which require time stamp, should be sent as data
packets with the following details:
1. FID valid = 1
2. FID value above the maximum FID
3. rx_router_port = 1

>From Spectrum-4 and on, this limitation will be solved.

Extend the function which handles TX header, in case that the packet is
a PTP packet, add TX header with type=data and all the above mentioned
requirements. Add operation as part of 'struct mlxsw_sp_ptp_ops', to be
able to separate the handling of PTP packets between different ASICs. Use
the data packet solution only for Spectrum-2 and Spectrum-3. Therefore, add
a dedicated operation structure for Spectrum-4, as it will be same to
Spectrum-2 in PTP implementation, just will not have the limitation of
control packets.

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
index dd7c94dd4c01..25d96bedf243 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
@@ -1385,3 +1385,37 @@ void mlxsw_sp2_ptp_fini(struct mlxsw_sp_ptp_state *ptp_state_common)
 	mlxsw_sp_ptp_traps_unset(mlxsw_sp);
 	kfree(ptp_state);
 }
+
+int mlxsw_sp_ptp_txhdr_construct(struct mlxsw_core *mlxsw_core,
+				 struct mlxsw_sp_port *mlxsw_sp_port,
+				 struct sk_buff *skb,
+				 const struct mlxsw_tx_info *tx_info)
+{
+	mlxsw_sp_txhdr_construct(skb, tx_info);
+	return 0;
+}
+
+int mlxsw_sp2_ptp_txhdr_construct(struct mlxsw_core *mlxsw_core,
+				  struct mlxsw_sp_port *mlxsw_sp_port,
+				  struct sk_buff *skb,
+				  const struct mlxsw_tx_info *tx_info)
+{
+	/* In Spectrum-2 and Spectrum-3, in order for PTP event packets to have
+	 * their correction field correctly set on the egress port they must be
+	 * transmitted as data packets. Such packets ingress the ASIC via the
+	 * CPU port and must have a VLAN tag, as the CPU port is not configured
+	 * with a PVID. Push the default VLAN (4095), which is configured as
+	 * egress untagged on all the ports.
+	 */
+	if (!skb_vlan_tagged(skb)) {
+		skb = vlan_insert_tag_set_proto(skb, htons(ETH_P_8021Q),
+						MLXSW_SP_DEFAULT_VID);
+		if (!skb) {
+			this_cpu_inc(mlxsw_sp_port->pcpu_stats->tx_dropped);
+			return -ENOMEM;
+		}
+	}
+
+	return mlxsw_sp_txhdr_ptp_data_construct(mlxsw_core, mlxsw_sp_port, skb,
+						 tx_info);
+}