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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 | ||
8551fad6 | 11 | #include <linux/skbuff.h> |
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12 | #include <net/dsa.h> |
13 | ||
14 | #include "dsa_priv.h" | |
15 | ||
16 | #define HELLCREEK_TAG_LEN 1 | |
17 | ||
18 | static struct sk_buff *hellcreek_xmit(struct sk_buff *skb, | |
19 | struct net_device *dev) | |
20 | { | |
21 | struct dsa_port *dp = dsa_slave_to_port(dev); | |
22 | u8 *tag; | |
23 | ||
0763120b KK |
24 | /* Calculate checksums (if required) before adding the trailer tag to |
25 | * avoid including it in calculations. That would lead to wrong | |
26 | * checksums after the switch strips the tag. | |
27 | */ | |
28 | if (skb->ip_summed == CHECKSUM_PARTIAL && | |
29 | skb_checksum_help(skb)) | |
30 | return NULL; | |
31 | ||
01ef09ca KK |
32 | /* Tag encoding */ |
33 | tag = skb_put(skb, HELLCREEK_TAG_LEN); | |
34 | *tag = BIT(dp->index); | |
35 | ||
36 | return skb; | |
37 | } | |
38 | ||
39 | static struct sk_buff *hellcreek_rcv(struct sk_buff *skb, | |
29a097b7 | 40 | struct net_device *dev) |
01ef09ca KK |
41 | { |
42 | /* Tag decoding */ | |
43 | u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN; | |
44 | unsigned int port = tag[0] & 0x03; | |
45 | ||
46 | skb->dev = dsa_master_find_slave(dev, 0, port); | |
47 | if (!skb->dev) { | |
52267ce2 | 48 | netdev_warn_once(dev, "Failed to get source port: %d\n", port); |
01ef09ca KK |
49 | return NULL; |
50 | } | |
51 | ||
52 | pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN); | |
53 | ||
bea79078 | 54 | dsa_default_offload_fwd_mark(skb); |
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55 | |
56 | return skb; | |
57 | } | |
58 | ||
59 | static const struct dsa_device_ops hellcreek_netdev_ops = { | |
60 | .name = "hellcreek", | |
61 | .proto = DSA_TAG_PROTO_HELLCREEK, | |
62 | .xmit = hellcreek_xmit, | |
63 | .rcv = hellcreek_rcv, | |
4e500251 | 64 | .needed_tailroom = HELLCREEK_TAG_LEN, |
01ef09ca KK |
65 | }; |
66 | ||
67 | MODULE_LICENSE("Dual MIT/GPL"); | |
68 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK); | |
69 | ||
70 | module_dsa_tag_driver(hellcreek_netdev_ops); |