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1/*
2 * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14#include <linux/dsa/lan9303.h>
15#include <linux/etherdevice.h>
16#include <linux/list.h>
17#include <linux/slab.h>
18
19#include "dsa_priv.h"
20
21/* To define the outgoing port and to discover the incoming port a regular
22 * VLAN tag is used by the LAN9303. But its VID meaning is 'special':
23 *
24 * Dest MAC Src MAC TAG Type
25 * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |...
26 * |<------->|
27 * TAG:
28 * |<------------->|
29 * | 1 2 | 3 4 |
30 * TPID VID
31 * 0x8100
32 *
33 * VID bit 3 indicates a request for an ALR lookup.
34 *
35 * If VID bit 3 is zero, then bits 0 and 1 specify the destination port
36 * (0, 1, 2) or broadcast (3) or the source port (1, 2).
37 *
38 * VID bit 4 is used to specify if the STP port state should be overridden.
39 * Required when no forwarding between the external ports should happen.
40 */
41
42#define LAN9303_TAG_LEN 4
43# define LAN9303_TAG_TX_USE_ALR BIT(3)
44# define LAN9303_TAG_TX_STP_OVERRIDE BIT(4)
45# define LAN9303_TAG_RX_IGMP BIT(3)
46# define LAN9303_TAG_RX_STP BIT(4)
47# define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \
48 LAN9303_TAG_RX_STP)
49
50/* Decide whether to transmit using ALR lookup, or transmit directly to
51 * port using tag. ALR learning is performed only when using ALR lookup.
52 * If the two external ports are bridged and the frame is unicast,
53 * then use ALR lookup to allow ALR learning on CPU port.
54 * Otherwise transmit directly to port with STP state override.
55 * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1
56 */
57static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr)
58{
59 struct lan9303 *chip = dp->ds->priv;
60
61 return chip->is_bridged && !is_multicast_ether_addr(dest_addr);
62}
63
64static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
65{
66 struct dsa_port *dp = dsa_slave_to_port(dev);
67 u16 *lan9303_tag;
68
69 /* insert a special VLAN tag between the MAC addresses
70 * and the current ethertype field.
71 */
72 if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) {
73 dev_dbg(&dev->dev,
74 "Cannot make room for the special tag. Dropping packet\n");
75 return NULL;
76 }
77
78 /* provide 'LAN9303_TAG_LEN' bytes additional space */
79 skb_push(skb, LAN9303_TAG_LEN);
80
81 /* make room between MACs and Ether-Type */
82 memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);
83
84 lan9303_tag = (u16 *)(skb->data + 2 * ETH_ALEN);
85 lan9303_tag[0] = htons(ETH_P_8021Q);
86 lan9303_tag[1] = lan9303_xmit_use_arl(dp, skb->data) ?
87 LAN9303_TAG_TX_USE_ALR :
88 dp->index | LAN9303_TAG_TX_STP_OVERRIDE;
89 lan9303_tag[1] = htons(lan9303_tag[1]);
90
91 return skb;
92}
93
94static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev,
95 struct packet_type *pt)
96{
97 u16 *lan9303_tag;
98 u16 lan9303_tag1;
99 unsigned int source_port;
100
101 if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
102 dev_warn_ratelimited(&dev->dev,
103 "Dropping packet, cannot pull\n");
104 return NULL;
105 }
106
107 /* '->data' points into the middle of our special VLAN tag information:
108 *
109 * ~ MAC src | 0x81 | 0x00 | 0xyy | 0xzz | ether type
110 * ^
111 * ->data
112 */
113 lan9303_tag = (u16 *)(skb->data - 2);
114
115 if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
116 dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
117 return NULL;
118 }
119
120 lan9303_tag1 = ntohs(lan9303_tag[1]);
121 source_port = lan9303_tag1 & 0x3;
122
123 skb->dev = dsa_master_find_slave(dev, 0, source_port);
124 if (!skb->dev) {
125 dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
126 return NULL;
127 }
128
129 /* remove the special VLAN tag between the MAC addresses
130 * and the current ethertype field.
131 */
132 skb_pull_rcsum(skb, 2 + 2);
133 memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
134 2 * ETH_ALEN);
135 skb->offload_fwd_mark = !(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU);
136
137 return skb;
138}
139
140const struct dsa_device_ops lan9303_netdev_ops = {
141 .xmit = lan9303_xmit,
142 .rcv = lan9303_rcv,
143};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
4 */
5#include <linux/dsa/lan9303.h>
6#include <linux/etherdevice.h>
7#include <linux/list.h>
8#include <linux/slab.h>
9
10#include "tag.h"
11
12/* To define the outgoing port and to discover the incoming port a regular
13 * VLAN tag is used by the LAN9303. But its VID meaning is 'special':
14 *
15 * Dest MAC Src MAC TAG Type
16 * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |...
17 * |<------->|
18 * TAG:
19 * |<------------->|
20 * | 1 2 | 3 4 |
21 * TPID VID
22 * 0x8100
23 *
24 * VID bit 3 indicates a request for an ALR lookup.
25 *
26 * If VID bit 3 is zero, then bits 0 and 1 specify the destination port
27 * (0, 1, 2) or broadcast (3) or the source port (1, 2).
28 *
29 * VID bit 4 is used to specify if the STP port state should be overridden.
30 * Required when no forwarding between the external ports should happen.
31 */
32
33#define LAN9303_NAME "lan9303"
34
35#define LAN9303_TAG_LEN 4
36# define LAN9303_TAG_TX_USE_ALR BIT(3)
37# define LAN9303_TAG_TX_STP_OVERRIDE BIT(4)
38# define LAN9303_TAG_RX_IGMP BIT(3)
39# define LAN9303_TAG_RX_STP BIT(4)
40# define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \
41 LAN9303_TAG_RX_STP)
42
43/* Decide whether to transmit using ALR lookup, or transmit directly to
44 * port using tag. ALR learning is performed only when using ALR lookup.
45 * If the two external ports are bridged and the frame is unicast,
46 * then use ALR lookup to allow ALR learning on CPU port.
47 * Otherwise transmit directly to port with STP state override.
48 * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1
49 */
50static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr)
51{
52 struct lan9303 *chip = dp->ds->priv;
53
54 return chip->is_bridged && !is_multicast_ether_addr(dest_addr);
55}
56
57static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
58{
59 struct dsa_port *dp = dsa_user_to_port(dev);
60 __be16 *lan9303_tag;
61 u16 tag;
62
63 /* provide 'LAN9303_TAG_LEN' bytes additional space */
64 skb_push(skb, LAN9303_TAG_LEN);
65
66 /* make room between MACs and Ether-Type */
67 dsa_alloc_etype_header(skb, LAN9303_TAG_LEN);
68
69 lan9303_tag = dsa_etype_header_pos_tx(skb);
70
71 tag = lan9303_xmit_use_arl(dp, skb->data) ?
72 LAN9303_TAG_TX_USE_ALR :
73 dp->index | LAN9303_TAG_TX_STP_OVERRIDE;
74 lan9303_tag[0] = htons(ETH_P_8021Q);
75 lan9303_tag[1] = htons(tag);
76
77 return skb;
78}
79
80static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev)
81{
82 u16 lan9303_tag1;
83 unsigned int source_port;
84
85 if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
86 dev_warn_ratelimited(&dev->dev,
87 "Dropping packet, cannot pull\n");
88 return NULL;
89 }
90
91 if (skb_vlan_tag_present(skb)) {
92 lan9303_tag1 = skb_vlan_tag_get(skb);
93 __vlan_hwaccel_clear_tag(skb);
94 } else {
95 skb_push_rcsum(skb, ETH_HLEN);
96 __skb_vlan_pop(skb, &lan9303_tag1);
97 skb_pull_rcsum(skb, ETH_HLEN);
98 }
99
100 source_port = lan9303_tag1 & 0x3;
101
102 skb->dev = dsa_conduit_find_user(dev, 0, source_port);
103 if (!skb->dev) {
104 dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
105 return NULL;
106 }
107
108 if (!(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU))
109 dsa_default_offload_fwd_mark(skb);
110
111 return skb;
112}
113
114static const struct dsa_device_ops lan9303_netdev_ops = {
115 .name = LAN9303_NAME,
116 .proto = DSA_TAG_PROTO_LAN9303,
117 .xmit = lan9303_xmit,
118 .rcv = lan9303_rcv,
119 .needed_headroom = LAN9303_TAG_LEN,
120};
121
122MODULE_DESCRIPTION("DSA tag driver for SMSC/Microchip LAN9303 family of switches");
123MODULE_LICENSE("GPL");
124MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303, LAN9303_NAME);
125
126module_dsa_tag_driver(lan9303_netdev_ops);