1 | // SPDX-License-Identifier: (GPL-2.0 OR MIT) |
2 | /* |
3 | * net/dsa/tag_hellcreek.c - Hirschmann Hellcreek switch tag format handling |
4 | * |
5 | * Copyright (C) 2019,2020 Linutronix GmbH |
6 | * Author Kurt Kanzenbach <kurt@linutronix.de> |
7 | * |
8 | * Based on tag_ksz.c. |
9 | */ |
10 | |
11 | #include <linux/skbuff.h> |
12 | #include <net/dsa.h> |
13 | |
14 | #include "tag.h" |
15 | |
16 | #define HELLCREEK_NAME "hellcreek" |
17 | |
18 | #define HELLCREEK_TAG_LEN 1 |
19 | |
20 | static struct sk_buff *hellcreek_xmit(struct sk_buff *skb, |
21 | struct net_device *dev) |
22 | { |
23 | struct dsa_port *dp = dsa_user_to_port(dev); |
24 | u8 *tag; |
25 | |
26 | /* Calculate checksums (if required) before adding the trailer tag to |
27 | * avoid including it in calculations. That would lead to wrong |
28 | * checksums after the switch strips the tag. |
29 | */ |
30 | if (skb->ip_summed == CHECKSUM_PARTIAL && |
31 | skb_checksum_help(skb)) |
32 | return NULL; |
33 | |
34 | /* Tag encoding */ |
35 | tag = skb_put(skb, HELLCREEK_TAG_LEN); |
36 | *tag = BIT(dp->index); |
37 | |
38 | return skb; |
39 | } |
40 | |
41 | static struct sk_buff *hellcreek_rcv(struct sk_buff *skb, |
42 | struct net_device *dev) |
43 | { |
44 | /* Tag decoding */ |
45 | u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN; |
46 | unsigned int port = tag[0] & 0x03; |
47 | |
48 | skb->dev = dsa_conduit_find_user(dev, device: 0, port); |
49 | if (!skb->dev) { |
50 | netdev_warn_once(dev, "Failed to get source port: %d\n" , port); |
51 | return NULL; |
52 | } |
53 | |
54 | if (pskb_trim_rcsum(skb, len: skb->len - HELLCREEK_TAG_LEN)) |
55 | return NULL; |
56 | |
57 | dsa_default_offload_fwd_mark(skb); |
58 | |
59 | return skb; |
60 | } |
61 | |
62 | static const struct dsa_device_ops hellcreek_netdev_ops = { |
63 | .name = HELLCREEK_NAME, |
64 | .proto = DSA_TAG_PROTO_HELLCREEK, |
65 | .xmit = hellcreek_xmit, |
66 | .rcv = hellcreek_rcv, |
67 | .needed_tailroom = HELLCREEK_TAG_LEN, |
68 | }; |
69 | |
70 | MODULE_DESCRIPTION("DSA tag driver for Hirschmann Hellcreek TSN switches" ); |
71 | MODULE_LICENSE("Dual MIT/GPL" ); |
72 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK, HELLCREEK_NAME); |
73 | |
74 | module_dsa_tag_driver(hellcreek_netdev_ops); |
75 | |