1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Motorcomm YT921x Switch Extended CPU Port Tagging
*
* Copyright (c) 2025 David Yang <mmyangfl@gmail.com>
*
* +----+----+-------+-----+----+---------
* | DA | SA | TagET | Tag | ET | Payload ...
* +----+----+-------+-----+----+---------
* 6 6 2 6 2 N
*
* Tag Ethertype: CPU_TAG_TPID_TPID (default: ETH_P_YT921X = 0x9988)
* * Hardcoded for the moment, but still configurable. Discuss it if there
* are conflicts somewhere and/or you want to change it for some reason.
* Tag:
* 2: VLAN Tag
* 2: Rx Port
* 15b: Rx Port Valid
* 14b-11b: Rx Port
* 10b-0b: Cmd?
* 2: Tx Port(s)
* 15b: Tx Port(s) Valid
* 10b-0b: Tx Port(s) Mask
*/
#include <linux/etherdevice.h>
#include "tag.h"
#define YT921X_TAG_NAME "yt921x"
#define YT921X_TAG_LEN 8
#define YT921X_TAG_PORT_EN BIT(15)
#define YT921X_TAG_RX_PORT_M GENMASK(14, 11)
#define YT921X_TAG_RX_CMD_M GENMASK(10, 0)
#define YT921X_TAG_RX_CMD(x) FIELD_PREP(YT921X_TAG_RX_CMD_M, (x))
#define YT921X_TAG_RX_CMD_FORWARDED 0x80
#define YT921X_TAG_RX_CMD_UNK_UCAST 0xb2
#define YT921X_TAG_RX_CMD_UNK_MCAST 0xb4
#define YT921X_TAG_TX_PORTS GENMASK(10, 0)
static struct sk_buff *
yt921x_tag_xmit(struct sk_buff *skb, struct net_device *netdev)
{
__be16 *tag;
u16 tx;
skb_push(skb, YT921X_TAG_LEN);
dsa_alloc_etype_header(skb, YT921X_TAG_LEN);
tag = dsa_etype_header_pos_tx(skb);
tag[0] = htons(ETH_P_YT921X);
/* VLAN tag unrelated when TX */
tag[1] = 0;
tag[2] = 0;
tx = FIELD_PREP(YT921X_TAG_TX_PORTS, dsa_xmit_port_mask(skb, netdev)) |
YT921X_TAG_PORT_EN;
tag[3] = htons(tx);
return skb;
}
static struct sk_buff *
yt921x_tag_rcv(struct sk_buff *skb, struct net_device *netdev)
{
unsigned int port;
__be16 *tag;
u16 cmd;
u16 rx;
if (unlikely(!pskb_may_pull(skb, YT921X_TAG_LEN)))
return NULL;
tag = dsa_etype_header_pos_rx(skb);
if (unlikely(tag[0] != htons(ETH_P_YT921X))) {
dev_warn_ratelimited(&netdev->dev,
"Unexpected EtherType 0x%04x\n",
ntohs(tag[0]));
return NULL;
}
/* Locate which port this is coming from */
rx = ntohs(tag[2]);
if (unlikely((rx & YT921X_TAG_PORT_EN) == 0)) {
dev_warn_ratelimited(&netdev->dev,
"Unexpected rx tag 0x%04x\n", rx);
return NULL;
}
port = FIELD_GET(YT921X_TAG_RX_PORT_M, rx);
skb->dev = dsa_conduit_find_user(netdev, 0, port);
if (unlikely(!skb->dev)) {
dev_warn_ratelimited(&netdev->dev,
"Couldn't decode source port %u\n", port);
return NULL;
}
cmd = FIELD_GET(YT921X_TAG_RX_CMD_M, rx);
switch (cmd) {
case YT921X_TAG_RX_CMD_FORWARDED:
/* Already forwarded by hardware */
dsa_default_offload_fwd_mark(skb);
break;
case YT921X_TAG_RX_CMD_UNK_UCAST:
case YT921X_TAG_RX_CMD_UNK_MCAST:
/* NOTE: hardware doesn't distinguish between TRAP (copy to CPU
* only) and COPY (forward and copy to CPU). In order to perform
* a soft switch, NEVER use COPY action in the switch driver.
*/
break;
default:
dev_warn_ratelimited(&netdev->dev,
"Unexpected rx cmd 0x%02x\n", cmd);
break;
}
/* Remove YT921x tag and update checksum */
skb_pull_rcsum(skb, YT921X_TAG_LEN);
dsa_strip_etype_header(skb, YT921X_TAG_LEN);
return skb;
}
static const struct dsa_device_ops yt921x_netdev_ops = {
.name = YT921X_TAG_NAME,
.proto = DSA_TAG_PROTO_YT921X,
.xmit = yt921x_tag_xmit,
.rcv = yt921x_tag_rcv,
.needed_headroom = YT921X_TAG_LEN,
};
MODULE_DESCRIPTION("DSA tag driver for Motorcomm YT921x switches");
MODULE_LICENSE("GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_YT921X, YT921X_TAG_NAME);
module_dsa_tag_driver(yt921x_netdev_ops);
|
