net: dsa: sja1105: prepare tagger for handling DSA tags and VLAN simultaneously

In VLAN-unaware mode, sja1105 uses VLAN tags with a custom TPID of 0xdadb. While in the yet-to-be introduced best_effort_vlan_filtering mode, it needs to work with normal VLAN TPID values. A complication arises when we must transmit a VLAN-tagged packet to the switch when it's in VLAN-aware mode. We need to construct a packet with 2 VLAN tags, and the switch will use the outer header for routing and pop it on egress. But sadly, here the 2 hardware generations don't behave the same: - E/T switches won't pop an ETH_P_8021AD tag on egress, it seems (packets will remain double-tagged). - P/Q/R/S switches will drop a packet with 2 ETH_P_8021Q tags (it looks like it tries to prevent VLAN hopping). But looks like the reverse is also true: - E/T switches have no problem popping the outer tag from packets with 2 ETH_P_8021Q tags. - P/Q/R/S will have no problem popping a single tag even if that is ETH_P_8021AD. So it is clear that if we want the hardware to work with dsa_8021q tagging in VLAN-aware mode, we need to send different TPIDs depending on revision. Keep that information in priv->info->qinq_tpid. The per-port tagger structure will hold an xmit_tpid value that depends not only upon the qinq_tpid, but also upon the VLAN awareness state itself (in case we must transmit using 0xdadb).

Vladimir Oltean committed 6 years ago

Commit 38b5bee1 parent cfa36b15 files · +44 −11Browse files

Unified · Split

5 files

drivers/net/dsa/sja1105/sja1105.h +6 −0
drivers/net/dsa/sja1105/sja1105_main.c +10 −0
drivers/net/dsa/sja1105/sja1105_spi.c +6 −0
include/linux/dsa/sja1105.h +1 −0
net/dsa/tag_sja1105.c +21 −11

drivers/net/dsa/sja1105/sja1105.h+6−0

 	const struct sja1105_dynamic_table_ops *dyn_ops;
 	const struct sja1105_table_ops *static_ops;
 	const struct sja1105_regs *regs;
+	/* Both E/T and P/Q/R/S have quirks when it comes to popping the S-Tag
+	 * from double-tagged frames. E/T will pop it only when it's equal to
+	 * TPID from the General Parameters Table, while P/Q/R/S will only
+	 * pop it when it's equal to TPID2.
+	 */
+	u16 qinq_tpid;
 	int (*reset_cmd)(struct dsa_switch *ds);
 	int (*setup_rgmii_delay)(const void *ctx, int port);
 	/* Prototypes from include/net/dsa.h */

drivers/net/dsa/sja1105/sja1105_main.c+10−0

 		tpid2 = ETH_P_SJA1105;
 	}
+	for (port = 0; port < ds->num_ports; port++) {
+		struct sja1105_port *sp = &priv->ports[port];
+		if (enabled)
+			sp->xmit_tpid = priv->info->qinq_tpid;
+		else
+			sp->xmit_tpid = ETH_P_SJA1105;
+	}
 	if (!enabled)
 		state = SJA1105_VLAN_UNAWARE;
 	else
 			goto out;
 		}
 		skb_queue_head_init(&sp->xmit_queue);
+		sp->xmit_tpid = ETH_P_SJA1105;
 	}
 	return 0;

drivers/net/dsa/sja1105/sja1105_spi.c+6−0

 	.part_no		= SJA1105ET_PART_NO,
 	.static_ops		= sja1105e_table_ops,
 	.dyn_ops		= sja1105et_dyn_ops,
+	.qinq_tpid		= ETH_P_8021Q,
 	.ptp_ts_bits		= 24,
 	.ptpegr_ts_bytes	= 4,
 	.reset_cmd		= sja1105et_reset_cmd,
 	.part_no		= SJA1105ET_PART_NO,
 	.static_ops		= sja1105t_table_ops,
 	.dyn_ops		= sja1105et_dyn_ops,
+	.qinq_tpid		= ETH_P_8021Q,
 	.ptp_ts_bits		= 24,
 	.ptpegr_ts_bytes	= 4,
 	.reset_cmd		= sja1105et_reset_cmd,
 	.part_no		= SJA1105P_PART_NO,
 	.static_ops		= sja1105p_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
+	.qinq_tpid		= ETH_P_8021AD,
 	.ptp_ts_bits		= 32,
 	.ptpegr_ts_bytes	= 8,
 	.setup_rgmii_delay	= sja1105pqrs_setup_rgmii_delay,
 	.part_no		= SJA1105Q_PART_NO,
 	.static_ops		= sja1105q_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
+	.qinq_tpid		= ETH_P_8021AD,
 	.ptp_ts_bits		= 32,
 	.ptpegr_ts_bytes	= 8,
 	.setup_rgmii_delay	= sja1105pqrs_setup_rgmii_delay,
 	.part_no		= SJA1105R_PART_NO,
 	.static_ops		= sja1105r_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
+	.qinq_tpid		= ETH_P_8021AD,
 	.ptp_ts_bits		= 32,
 	.ptpegr_ts_bytes	= 8,
 	.setup_rgmii_delay	= sja1105pqrs_setup_rgmii_delay,
 	.static_ops		= sja1105s_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
 	.regs			= &sja1105pqrs_regs,
+	.qinq_tpid		= ETH_P_8021AD,
 	.ptp_ts_bits		= 32,
 	.ptpegr_ts_bytes	= 8,
 	.setup_rgmii_delay	= sja1105pqrs_setup_rgmii_delay,

include/linux/dsa/sja1105.h+1−0

@@ -59,6 +59,7 @@ struct sja1105_port { · 58 unmodified lines
59	struct sja1105_tagger_data *data;	59	struct sja1105_tagger_data *data;
60	struct dsa_port *dp;	60	struct dsa_port *dp;
61	bool hwts_tx_en;	61	bool hwts_tx_en;
		62	u16 xmit_tpid;
62	};	63	};
63		64
64	#endif /* _NET_DSA_SJA1105_H */	65	#endif /* _NET_DSA_SJA1105_H */

net/dsa/tag_sja1105.c+21−11

 	return true;
 }
+static bool sja1105_can_use_vlan_as_tags(const struct sk_buff *skb)
+{
+	struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+	if (hdr->h_vlan_proto == ntohs(ETH_P_SJA1105))
+		return true;
+	if (hdr->h_vlan_proto != ntohs(ETH_P_8021Q))
+		return false;
+	return vid_is_dsa_8021q(ntohs(hdr->h_vlan_TCI) & VLAN_VID_MASK);
+}
 /* This is the first time the tagger sees the frame on RX.
  * Figure out if we can decode it.
  */
 static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev)
 {
-	if (!dsa_port_is_vlan_filtering(dev->dsa_ptr))
+	if (sja1105_can_use_vlan_as_tags(skb))
 		return true;
 	if (sja1105_is_link_local(skb))
 		return true;
 	return NULL;
 }
+static u16 sja1105_xmit_tpid(struct sja1105_port *sp)
+{
+	return sp->xmit_tpid;
+}
 static struct sk_buff *sja1105_xmit(struct sk_buff *skb,
 				    struct net_device *netdev)
 {
 	if (unlikely(sja1105_is_link_local(skb)))
 		return sja1105_defer_xmit(dp->priv, skb);
-	/* If we are under a vlan_filtering bridge, IP termination on
+	return dsa_8021q_xmit(skb, netdev, sja1105_xmit_tpid(dp->priv),
-	 * switch ports based on 802.1Q tags is simply too brittle to
-	 * be passable. So just defer to the dsa_slave_notag_xmit
-	 * implementation.
-	 */
-	if (dsa_port_is_vlan_filtering(dp))
-		return skb;
-	return dsa_8021q_xmit(skb, netdev, ETH_P_SJA1105,
 			     ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
 }
 	hdr = eth_hdr(skb);
 	tpid = ntohs(hdr->h_proto);
-	is_tagged = (tpid == ETH_P_SJA1105);
+	is_tagged = (tpid == ETH_P_SJA1105 || tpid == ETH_P_8021Q);
 	is_link_local = sja1105_is_link_local(skb);
 	is_meta = sja1105_is_meta_frame(skb);