1// SPDX-License-Identifier: GPL-2.0
2/* Copyright 2020-2021 NXP
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 <linux/dsa/ocelot.h>
13
14#include "tag.h"
15#include "tag_8021q.h"
16
17#define OCELOT_8021Q_NAME "ocelot-8021q"
18
19struct ocelot_8021q_tagger_private {
20	struct ocelot_8021q_tagger_data data; /* Must be first */
21	struct kthread_worker *xmit_worker;
22};
23
24static struct sk_buff *ocelot_defer_xmit(struct dsa_port *dp,
25					 struct sk_buff *skb)
26{
27	struct ocelot_8021q_tagger_private *priv = dp->ds->tagger_data;
28	struct ocelot_8021q_tagger_data *data = &priv->data;
29	void (*xmit_work_fn)(struct kthread_work *work);
30	struct felix_deferred_xmit_work *xmit_work;
31	struct kthread_worker *xmit_worker;
32
33	xmit_work_fn = data->xmit_work_fn;
34	xmit_worker = priv->xmit_worker;
35
36	if (!xmit_work_fn || !xmit_worker)
37		return NULL;
38
39	/* PTP over IP packets need UDP checksumming. We may have inherited
40	 * NETIF_F_HW_CSUM from the DSA conduit, but these packets are not sent
41	 * through the DSA conduit, so calculate the checksum here.
42	 */
43	if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
44		return NULL;
45
46	xmit_work = kzalloc(sizeof(*xmit_work), GFP_ATOMIC);
47	if (!xmit_work)
48		return NULL;
49
50	/* Calls felix_port_deferred_xmit in felix.c */
51	kthread_init_work(&xmit_work->work, xmit_work_fn);
52	/* Increase refcount so the kfree_skb in dsa_user_xmit
53	 * won't really free the packet.
54	 */
55	xmit_work->dp = dp;
56	xmit_work->skb = skb_get(skb);
57
58	kthread_queue_work(xmit_worker, &xmit_work->work);
59
60	return NULL;
61}
62
63static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
64				   struct net_device *netdev)
65{
66	struct dsa_port *dp = dsa_user_to_port(netdev);
67	u16 queue_mapping = skb_get_queue_mapping(skb);
68	u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
69	u16 tx_vid = dsa_tag_8021q_standalone_vid(dp);
70	struct ethhdr *hdr = eth_hdr(skb);
71
72	if (ocelot_ptp_rew_op(skb) || is_link_local_ether_addr(hdr->h_dest))
73		return ocelot_defer_xmit(dp, skb);
74
75	return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
76			      ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
77}
78
79static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
80				  struct net_device *netdev)
81{
82	int src_port, switch_id;
83
84	dsa_8021q_rcv(skb, &src_port, &switch_id, NULL);
85
86	skb->dev = dsa_conduit_find_user(netdev, switch_id, src_port);
87	if (!skb->dev)
88		return NULL;
89
90	dsa_default_offload_fwd_mark(skb);
91
92	return skb;
93}
94
95static void ocelot_disconnect(struct dsa_switch *ds)
96{
97	struct ocelot_8021q_tagger_private *priv = ds->tagger_data;
98
99	kthread_destroy_worker(priv->xmit_worker);
100	kfree(priv);
101	ds->tagger_data = NULL;
102}
103
104static int ocelot_connect(struct dsa_switch *ds)
105{
106	struct ocelot_8021q_tagger_private *priv;
107	int err;
108
109	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
110	if (!priv)
111		return -ENOMEM;
112
113	priv->xmit_worker = kthread_create_worker(0, "felix_xmit");
114	if (IS_ERR(priv->xmit_worker)) {
115		err = PTR_ERR(priv->xmit_worker);
116		kfree(priv);
117		return err;
118	}
119
120	ds->tagger_data = priv;
121
122	return 0;
123}
124
125static const struct dsa_device_ops ocelot_8021q_netdev_ops = {
126	.name			= OCELOT_8021Q_NAME,
127	.proto			= DSA_TAG_PROTO_OCELOT_8021Q,
128	.xmit			= ocelot_xmit,
129	.rcv			= ocelot_rcv,
130	.connect		= ocelot_connect,
131	.disconnect		= ocelot_disconnect,
132	.needed_headroom	= VLAN_HLEN,
133	.promisc_on_conduit	= true,
134};
135
136MODULE_DESCRIPTION("DSA tag driver for Ocelot family of switches, using VLAN");
137MODULE_LICENSE("GPL v2");
138MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT_8021Q, OCELOT_8021Q_NAME);
139
140module_dsa_tag_driver(ocelot_8021q_netdev_ops);
141