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 "dsa_priv.h"
11
12static struct sk_buff *xrs700x_xmit(struct sk_buff *skb, struct net_device *dev)
13{
14	struct dsa_port *partner, *dp = dsa_slave_to_port(dev);
15	u8 *trailer;
16
17	trailer = skb_put(skb, 1);
18	trailer[0] = BIT(dp->index);
19
20	if (dp->hsr_dev)
21		dsa_hsr_foreach_port(partner, dp->ds, dp->hsr_dev)
22			if (partner != dp)
23				trailer[0] |= BIT(partner->index);
24
25	return skb;
26}
27
28static struct sk_buff *xrs700x_rcv(struct sk_buff *skb, struct net_device *dev,
29				   struct packet_type *pt)
30{
31	int source_port;
32	u8 *trailer;
33
34	trailer = skb_tail_pointer(skb) - 1;
35
36	source_port = ffs((int)trailer[0]) - 1;
37
38	if (source_port < 0)
39		return NULL;
40
41	skb->dev = dsa_master_find_slave(dev, 0, source_port);
42	if (!skb->dev)
43		return NULL;
44
45	if (pskb_trim_rcsum(skb, skb->len - 1))
46		return NULL;
47
48	/* Frame is forwarded by hardware, don't forward in software. */
49	skb->offload_fwd_mark = 1;
50
51	return skb;
52}
53
54static const struct dsa_device_ops xrs700x_netdev_ops = {
55	.name	= "xrs700x",
56	.proto	= DSA_TAG_PROTO_XRS700X,
57	.xmit	= xrs700x_xmit,
58	.rcv	= xrs700x_rcv,
59	.needed_tailroom = 1,
60};
61
62MODULE_LICENSE("GPL");
63MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_XRS700X);
64
65module_dsa_tag_driver(xrs700x_netdev_ops);