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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Mediatek DSA Tag support
4 * Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
5 * Sean Wang <sean.wang@mediatek.com>
6 */
7
8#include <linux/etherdevice.h>
9#include <linux/if_vlan.h>
10
11#include "dsa_priv.h"
12
13#define MTK_HDR_LEN 4
14#define MTK_HDR_XMIT_UNTAGGED 0
15#define MTK_HDR_XMIT_TAGGED_TPID_8100 1
16#define MTK_HDR_XMIT_TAGGED_TPID_88A8 2
17#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
18#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
19#define MTK_HDR_XMIT_SA_DIS BIT(6)
20
21static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
22 struct net_device *dev)
23{
24 struct dsa_port *dp = dsa_slave_to_port(dev);
25 u8 xmit_tpid;
26 u8 *mtk_tag;
27
28 /* Build the special tag after the MAC Source Address. If VLAN header
29 * is present, it's required that VLAN header and special tag is
30 * being combined. Only in this way we can allow the switch can parse
31 * the both special and VLAN tag at the same time and then look up VLAN
32 * table with VID.
33 */
34 switch (skb->protocol) {
35 case htons(ETH_P_8021Q):
36 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_8100;
37 break;
38 case htons(ETH_P_8021AD):
39 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_88A8;
40 break;
41 default:
42 xmit_tpid = MTK_HDR_XMIT_UNTAGGED;
43 skb_push(skb, MTK_HDR_LEN);
44 memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
45 }
46
47 mtk_tag = skb->data + 2 * ETH_ALEN;
48
49 /* Mark tag attribute on special tag insertion to notify hardware
50 * whether that's a combined special tag with 802.1Q header.
51 */
52 mtk_tag[0] = xmit_tpid;
53 mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
54
55 /* Tag control information is kept for 802.1Q */
56 if (xmit_tpid == MTK_HDR_XMIT_UNTAGGED) {
57 mtk_tag[2] = 0;
58 mtk_tag[3] = 0;
59 }
60
61 return skb;
62}
63
64static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
65 struct packet_type *pt)
66{
67 u16 hdr;
68 int port;
69 __be16 *phdr;
70
71 if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
72 return NULL;
73
74 /* The MTK header is added by the switch between src addr
75 * and ethertype at this point, skb->data points to 2 bytes
76 * after src addr so header should be 2 bytes right before.
77 */
78 phdr = (__be16 *)(skb->data - 2);
79 hdr = ntohs(*phdr);
80
81 /* Remove MTK tag and recalculate checksum. */
82 skb_pull_rcsum(skb, MTK_HDR_LEN);
83
84 memmove(skb->data - ETH_HLEN,
85 skb->data - ETH_HLEN - MTK_HDR_LEN,
86 2 * ETH_ALEN);
87
88 /* Get source port information */
89 port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
90
91 skb->dev = dsa_master_find_slave(dev, 0, port);
92 if (!skb->dev)
93 return NULL;
94
95 skb->offload_fwd_mark = 1;
96
97 return skb;
98}
99
100static const struct dsa_device_ops mtk_netdev_ops = {
101 .name = "mtk",
102 .proto = DSA_TAG_PROTO_MTK,
103 .xmit = mtk_tag_xmit,
104 .rcv = mtk_tag_rcv,
105 .needed_headroom = MTK_HDR_LEN,
106};
107
108MODULE_LICENSE("GPL");
109MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK);
110
111module_dsa_tag_driver(mtk_netdev_ops);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Mediatek DSA Tag support
4 * Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
5 * Sean Wang <sean.wang@mediatek.com>
6 */
7
8#include <linux/etherdevice.h>
9#include <linux/if_vlan.h>
10
11#include "tag.h"
12
13#define MTK_NAME "mtk"
14
15#define MTK_HDR_LEN 4
16#define MTK_HDR_XMIT_UNTAGGED 0
17#define MTK_HDR_XMIT_TAGGED_TPID_8100 1
18#define MTK_HDR_XMIT_TAGGED_TPID_88A8 2
19#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
20#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
21#define MTK_HDR_XMIT_SA_DIS BIT(6)
22
23static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
24 struct net_device *dev)
25{
26 struct dsa_port *dp = dsa_user_to_port(dev);
27 u8 xmit_tpid;
28 u8 *mtk_tag;
29
30 skb_set_queue_mapping(skb, dp->index);
31
32 /* Build the special tag after the MAC Source Address. If VLAN header
33 * is present, it's required that VLAN header and special tag is
34 * being combined. Only in this way we can allow the switch can parse
35 * the both special and VLAN tag at the same time and then look up VLAN
36 * table with VID.
37 */
38 switch (skb->protocol) {
39 case htons(ETH_P_8021Q):
40 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_8100;
41 break;
42 case htons(ETH_P_8021AD):
43 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_88A8;
44 break;
45 default:
46 xmit_tpid = MTK_HDR_XMIT_UNTAGGED;
47 skb_push(skb, MTK_HDR_LEN);
48 dsa_alloc_etype_header(skb, MTK_HDR_LEN);
49 }
50
51 mtk_tag = dsa_etype_header_pos_tx(skb);
52
53 /* Mark tag attribute on special tag insertion to notify hardware
54 * whether that's a combined special tag with 802.1Q header.
55 */
56 mtk_tag[0] = xmit_tpid;
57 mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
58
59 /* Tag control information is kept for 802.1Q */
60 if (xmit_tpid == MTK_HDR_XMIT_UNTAGGED) {
61 mtk_tag[2] = 0;
62 mtk_tag[3] = 0;
63 }
64
65 return skb;
66}
67
68static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev)
69{
70 u16 hdr;
71 int port;
72 __be16 *phdr;
73
74 if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
75 return NULL;
76
77 phdr = dsa_etype_header_pos_rx(skb);
78 hdr = ntohs(*phdr);
79
80 /* Remove MTK tag and recalculate checksum. */
81 skb_pull_rcsum(skb, MTK_HDR_LEN);
82
83 dsa_strip_etype_header(skb, MTK_HDR_LEN);
84
85 /* Get source port information */
86 port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
87
88 skb->dev = dsa_conduit_find_user(dev, 0, port);
89 if (!skb->dev)
90 return NULL;
91
92 dsa_default_offload_fwd_mark(skb);
93
94 return skb;
95}
96
97static const struct dsa_device_ops mtk_netdev_ops = {
98 .name = MTK_NAME,
99 .proto = DSA_TAG_PROTO_MTK,
100 .xmit = mtk_tag_xmit,
101 .rcv = mtk_tag_rcv,
102 .needed_headroom = MTK_HDR_LEN,
103};
104
105MODULE_DESCRIPTION("DSA tag driver for Mediatek switches");
106MODULE_LICENSE("GPL");
107MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK, MTK_NAME);
108
109module_dsa_tag_driver(mtk_netdev_ops);