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 | */ |
50 | static 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(addr: dest_addr); |
55 | } |
56 | |
57 | static 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, dest_addr: 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 | |
80 | static 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, vlan_tci: &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, device: 0, port: 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 | |
114 | static 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 | |
122 | MODULE_LICENSE("GPL" ); |
123 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303, LAN9303_NAME); |
124 | |
125 | module_dsa_tag_driver(lan9303_netdev_ops); |
126 | |