tag_ocelot_8021q.c

  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 = -1, switch_id = -1;
 83
 84	dsa_8021q_rcv(skb, &src_port, &switch_id, NULL, 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_run_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);