1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2022 Schneider Electric |
4 | * |
5 | * Clément Léger <clement.leger@bootlin.com> |
6 | */ |
7 | |
8 | #include <linux/bitfield.h> |
9 | #include <linux/etherdevice.h> |
10 | #include <linux/if_ether.h> |
11 | #include <net/dsa.h> |
12 | |
13 | #include "tag.h" |
14 | |
15 | /* To define the outgoing port and to discover the incoming port a TAG is |
16 | * inserted after Src MAC : |
17 | * |
18 | * Dest MAC Src MAC TAG Type |
19 | * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 5 6 7 8 | 1 2 |... |
20 | * |<--------------->| |
21 | * |
22 | * See struct a5psw_tag for layout |
23 | */ |
24 | |
25 | #define A5PSW_NAME "a5psw" |
26 | |
27 | #define ETH_P_DSA_A5PSW 0xE001 |
28 | #define A5PSW_TAG_LEN 8 |
29 | #define A5PSW_CTRL_DATA_FORCE_FORWARD BIT(0) |
30 | /* This is both used for xmit tag and rcv tagging */ |
31 | #define A5PSW_CTRL_DATA_PORT GENMASK(3, 0) |
32 | |
33 | struct a5psw_tag { |
34 | __be16 ctrl_tag; |
35 | __be16 ctrl_data; |
36 | __be16 ctrl_data2_hi; |
37 | __be16 ctrl_data2_lo; |
38 | }; |
39 | |
40 | static struct sk_buff *a5psw_tag_xmit(struct sk_buff *skb, struct net_device *dev) |
41 | { |
42 | struct dsa_port *dp = dsa_user_to_port(dev); |
43 | struct a5psw_tag *ptag; |
44 | u32 data2_val; |
45 | |
46 | BUILD_BUG_ON(sizeof(*ptag) != A5PSW_TAG_LEN); |
47 | |
48 | /* The Ethernet switch we are interfaced with needs packets to be at |
49 | * least 60 bytes otherwise they will be discarded when they enter the |
50 | * switch port logic. |
51 | */ |
52 | if (__skb_put_padto(skb, ETH_ZLEN, free_on_error: false)) |
53 | return NULL; |
54 | |
55 | /* provide 'A5PSW_TAG_LEN' bytes additional space */ |
56 | skb_push(skb, A5PSW_TAG_LEN); |
57 | |
58 | /* make room between MACs and Ether-Type to insert tag */ |
59 | dsa_alloc_etype_header(skb, A5PSW_TAG_LEN); |
60 | |
61 | ptag = dsa_etype_header_pos_tx(skb); |
62 | |
63 | data2_val = FIELD_PREP(A5PSW_CTRL_DATA_PORT, BIT(dp->index)); |
64 | ptag->ctrl_tag = htons(ETH_P_DSA_A5PSW); |
65 | ptag->ctrl_data = htons(A5PSW_CTRL_DATA_FORCE_FORWARD); |
66 | ptag->ctrl_data2_lo = htons(data2_val); |
67 | ptag->ctrl_data2_hi = 0; |
68 | |
69 | return skb; |
70 | } |
71 | |
72 | static struct sk_buff *a5psw_tag_rcv(struct sk_buff *skb, |
73 | struct net_device *dev) |
74 | { |
75 | struct a5psw_tag *tag; |
76 | int port; |
77 | |
78 | if (unlikely(!pskb_may_pull(skb, A5PSW_TAG_LEN))) { |
79 | dev_warn_ratelimited(&dev->dev, |
80 | "Dropping packet, cannot pull\n" ); |
81 | return NULL; |
82 | } |
83 | |
84 | tag = dsa_etype_header_pos_rx(skb); |
85 | |
86 | if (tag->ctrl_tag != htons(ETH_P_DSA_A5PSW)) { |
87 | dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid TAG marker\n" ); |
88 | return NULL; |
89 | } |
90 | |
91 | port = FIELD_GET(A5PSW_CTRL_DATA_PORT, ntohs(tag->ctrl_data)); |
92 | |
93 | skb->dev = dsa_conduit_find_user(dev, device: 0, port); |
94 | if (!skb->dev) |
95 | return NULL; |
96 | |
97 | skb_pull_rcsum(skb, A5PSW_TAG_LEN); |
98 | dsa_strip_etype_header(skb, A5PSW_TAG_LEN); |
99 | |
100 | dsa_default_offload_fwd_mark(skb); |
101 | |
102 | return skb; |
103 | } |
104 | |
105 | static const struct dsa_device_ops a5psw_netdev_ops = { |
106 | .name = A5PSW_NAME, |
107 | .proto = DSA_TAG_PROTO_RZN1_A5PSW, |
108 | .xmit = a5psw_tag_xmit, |
109 | .rcv = a5psw_tag_rcv, |
110 | .needed_headroom = A5PSW_TAG_LEN, |
111 | }; |
112 | |
113 | MODULE_DESCRIPTION("DSA tag driver for Renesas RZ/N1 A5PSW switch" ); |
114 | MODULE_LICENSE("GPL v2" ); |
115 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_A5PSW, A5PSW_NAME); |
116 | module_dsa_tag_driver(a5psw_netdev_ops); |
117 | |