xref: /openbmc/linux/net/dsa/tag_ocelot_8021q.c (revision dc3401c8)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright 2020-2021 NXP Semiconductors
3  *
4  * An implementation of the software-defined tag_8021q.c tagger format, which
5  * also preserves full functionality under a vlan_filtering bridge. It does
6  * this by using the TCAM engines for:
7  * - pushing the RX VLAN as a second, outer tag, on egress towards the CPU port
8  * - redirecting towards the correct front port based on TX VLAN and popping
9  *   that on egress
10  */
11 #include <linux/dsa/8021q.h>
12 #include <soc/mscc/ocelot.h>
13 #include <soc/mscc/ocelot_ptp.h>
14 #include "dsa_priv.h"
15 
16 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
17 				   struct net_device *netdev)
18 {
19 	struct dsa_port *dp = dsa_slave_to_port(netdev);
20 	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
21 	u16 queue_mapping = skb_get_queue_mapping(skb);
22 	u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
23 	struct ocelot *ocelot = dp->ds->priv;
24 	int port = dp->index;
25 	u32 rew_op = 0;
26 
27 	rew_op = ocelot_ptp_rew_op(skb);
28 	if (rew_op) {
29 		if (!ocelot_can_inject(ocelot, 0))
30 			return NULL;
31 
32 		ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
33 		return NULL;
34 	}
35 
36 	return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
37 			      ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
38 }
39 
40 static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
41 				  struct net_device *netdev)
42 {
43 	int src_port, switch_id;
44 
45 	dsa_8021q_rcv(skb, &src_port, &switch_id);
46 
47 	skb->dev = dsa_master_find_slave(netdev, switch_id, src_port);
48 	if (!skb->dev)
49 		return NULL;
50 
51 	dsa_default_offload_fwd_mark(skb);
52 
53 	return skb;
54 }
55 
56 static const struct dsa_device_ops ocelot_8021q_netdev_ops = {
57 	.name			= "ocelot-8021q",
58 	.proto			= DSA_TAG_PROTO_OCELOT_8021Q,
59 	.xmit			= ocelot_xmit,
60 	.rcv			= ocelot_rcv,
61 	.needed_headroom	= VLAN_HLEN,
62 	.promisc_on_master	= true,
63 };
64 
65 MODULE_LICENSE("GPL v2");
66 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT_8021Q);
67 
68 module_dsa_tag_driver(ocelot_8021q_netdev_ops);
69