1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * XRS700x tag format handling
4 * Copyright (c) 2008-2009 Marvell Semiconductor
5 * Copyright (c) 2020 NovaTech LLC
6 */
7
8#include <linux/bitops.h>
9
10#include "tag.h"
11
12#define XRS700X_NAME "xrs700x"
13
14static struct sk_buff *xrs700x_xmit(struct sk_buff *skb, struct net_device *dev)
15{
16	struct dsa_port *partner, *dp = dsa_user_to_port(dev);
17	u8 *trailer;
18
19	trailer = skb_put(skb, 1);
20	trailer[0] = BIT(dp->index);
21
22	if (dp->hsr_dev)
23		dsa_hsr_foreach_port(partner, dp->ds, dp->hsr_dev)
24			if (partner != dp)
25				trailer[0] |= BIT(partner->index);
26
27	return skb;
28}
29
30static struct sk_buff *xrs700x_rcv(struct sk_buff *skb, struct net_device *dev)
31{
32	int source_port;
33	u8 *trailer;
34
35	trailer = skb_tail_pointer(skb) - 1;
36
37	source_port = ffs((int)trailer[0]) - 1;
38
39	if (source_port < 0)
40		return NULL;
41
42	skb->dev = dsa_conduit_find_user(dev, 0, source_port);
43	if (!skb->dev)
44		return NULL;
45
46	if (pskb_trim_rcsum(skb, skb->len - 1))
47		return NULL;
48
49	/* Frame is forwarded by hardware, don't forward in software. */
50	dsa_default_offload_fwd_mark(skb);
51
52	return skb;
53}
54
55static const struct dsa_device_ops xrs700x_netdev_ops = {
56	.name	= XRS700X_NAME,
57	.proto	= DSA_TAG_PROTO_XRS700X,
58	.xmit	= xrs700x_xmit,
59	.rcv	= xrs700x_rcv,
60	.needed_tailroom = 1,
61};
62
63MODULE_DESCRIPTION("DSA tag driver for XRS700x switches");
64MODULE_LICENSE("GPL");
65MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_XRS700X, XRS700X_NAME);
66
67module_dsa_tag_driver(xrs700x_netdev_ops);
68