sfc: support PTP over Ethernet

The previous patch add support for PTP over IPv6/UDP (only for 8000
series and newer) and this one add support for PTP over 802.3.

Tested: sync as master and as slave is correct with ptp4l. PTP over IPv4
and IPv6 still works fine.
Suggested-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ptp.c

@@ -118,13 +118,14 @@
 
 #define	PTP_MIN_LENGTH		63
 
-#define PTP_RXFILTERS_LEN	4
+#define PTP_RXFILTERS_LEN	5
 
 #define PTP_ADDR_IPV4		0xe0000181	/* 224.0.1.129 */
 #define PTP_ADDR_IPV6		{0xff, 0x0e, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
 				0, 0x01, 0x81}	/* ff0e::181 */
 #define PTP_EVENT_PORT		319
 #define PTP_GENERAL_PORT	320
+#define PTP_ADDR_ETHER		{0x01, 0x1b, 0x19, 0, 0, 0} /* 01-1B-19-00-00-00 */
 
 /* Annoyingly the format of the version numbers are different between
  * versions 1 and 2 so it isn't possible to simply look for 1 or 2.
@@ -1342,6 +1343,18 @@ static int efx_ptp_insert_ipv6_filter(struct efx_nic *efx, u16 port)
 	return efx_ptp_insert_filter(efx, &rxfilter);
 }
 
+static int efx_ptp_insert_eth_filter(struct efx_nic *efx)
+{
+	const u8 addr[ETH_ALEN] = PTP_ADDR_ETHER;
+	struct efx_filter_spec rxfilter;
+
+	efx_ptp_init_filter(efx, &rxfilter);
+	efx_filter_set_eth_local(&rxfilter, EFX_FILTER_VID_UNSPEC, addr);
+	rxfilter.match_flags |= EFX_FILTER_MATCH_ETHER_TYPE;
+	rxfilter.ether_type = htons(ETH_P_1588);
+	return efx_ptp_insert_filter(efx, &rxfilter);
+}
+
 static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
 {
 	struct efx_ptp_data *ptp = efx->ptp_data;
@@ -1362,7 +1375,7 @@ static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
 		goto fail;
 
 	/* if the NIC supports hw timestamps by the MAC, we can support
-	 * PTP over IPv6
+	 * PTP over IPv6 and Ethernet
 	 */
 	if (efx_ptp_use_mac_tx_timestamps(efx)) {
 		rc = efx_ptp_insert_ipv6_filter(efx, PTP_EVENT_PORT);
@@ -1372,6 +1385,10 @@ static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
 		rc = efx_ptp_insert_ipv6_filter(efx, PTP_GENERAL_PORT);
 		if (rc < 0)
 			goto fail;
+
+		rc = efx_ptp_insert_eth_filter(efx);
+		if (rc < 0)
+			goto fail;
 	}
 
 	return 0;