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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Intel / Lantiq GSWIP V2.0 PMAC tag support
4 *
5 * Copyright (C) 2017 - 2018 Hauke Mehrtens <hauke@hauke-m.de>
6 */
7
8#include <linux/bitops.h>
9#include <linux/etherdevice.h>
10#include <linux/skbuff.h>
11#include <net/dsa.h>
12
13#include "tag.h"
14
15#define GSWIP_NAME "gswip"
16
17#define GSWIP_TX_HEADER_LEN 4
18
19/* special tag in TX path header */
20/* Byte 0 */
21#define GSWIP_TX_SLPID_SHIFT 0 /* source port ID */
22#define GSWIP_TX_SLPID_CPU 2
23#define GSWIP_TX_SLPID_APP1 3
24#define GSWIP_TX_SLPID_APP2 4
25#define GSWIP_TX_SLPID_APP3 5
26#define GSWIP_TX_SLPID_APP4 6
27#define GSWIP_TX_SLPID_APP5 7
28
29/* Byte 1 */
30#define GSWIP_TX_CRCGEN_DIS BIT(7)
31#define GSWIP_TX_DPID_SHIFT 0 /* destination group ID */
32#define GSWIP_TX_DPID_ELAN 0
33#define GSWIP_TX_DPID_EWAN 1
34#define GSWIP_TX_DPID_CPU 2
35#define GSWIP_TX_DPID_APP1 3
36#define GSWIP_TX_DPID_APP2 4
37#define GSWIP_TX_DPID_APP3 5
38#define GSWIP_TX_DPID_APP4 6
39#define GSWIP_TX_DPID_APP5 7
40
41/* Byte 2 */
42#define GSWIP_TX_PORT_MAP_EN BIT(7)
43#define GSWIP_TX_PORT_MAP_SEL BIT(6)
44#define GSWIP_TX_LRN_DIS BIT(5)
45#define GSWIP_TX_CLASS_EN BIT(4)
46#define GSWIP_TX_CLASS_SHIFT 0
47#define GSWIP_TX_CLASS_MASK GENMASK(3, 0)
48
49/* Byte 3 */
50#define GSWIP_TX_DPID_EN BIT(0)
51#define GSWIP_TX_PORT_MAP GENMASK(6, 1)
52
53#define GSWIP_RX_HEADER_LEN 8
54
55/* special tag in RX path header */
56/* Byte 7 */
57#define GSWIP_RX_SPPID_SHIFT 4
58#define GSWIP_RX_SPPID_MASK GENMASK(6, 4)
59
60static struct sk_buff *gswip_tag_xmit(struct sk_buff *skb,
61 struct net_device *dev)
62{
63 u8 *gswip_tag;
64
65 skb_push(skb, GSWIP_TX_HEADER_LEN);
66
67 gswip_tag = skb->data;
68 gswip_tag[0] = GSWIP_TX_SLPID_CPU;
69 gswip_tag[1] = GSWIP_TX_DPID_ELAN;
70 gswip_tag[2] = GSWIP_TX_PORT_MAP_EN | GSWIP_TX_PORT_MAP_SEL;
71 gswip_tag[3] = FIELD_PREP(GSWIP_TX_PORT_MAP, dsa_xmit_port_mask(skb, dev));
72 gswip_tag[3] |= GSWIP_TX_DPID_EN;
73
74 return skb;
75}
76
77static struct sk_buff *gswip_tag_rcv(struct sk_buff *skb,
78 struct net_device *dev)
79{
80 int port;
81 u8 *gswip_tag;
82
83 if (unlikely(!pskb_may_pull(skb, GSWIP_RX_HEADER_LEN)))
84 return NULL;
85
86 gswip_tag = skb->data - ETH_HLEN;
87
88 /* Get source port information */
89 port = (gswip_tag[7] & GSWIP_RX_SPPID_MASK) >> GSWIP_RX_SPPID_SHIFT;
90 skb->dev = dsa_conduit_find_user(dev, 0, port);
91 if (!skb->dev)
92 return NULL;
93
94 /* remove GSWIP tag */
95 skb_pull_rcsum(skb, GSWIP_RX_HEADER_LEN);
96
97 return skb;
98}
99
100static const struct dsa_device_ops gswip_netdev_ops = {
101 .name = GSWIP_NAME,
102 .proto = DSA_TAG_PROTO_GSWIP,
103 .xmit = gswip_tag_xmit,
104 .rcv = gswip_tag_rcv,
105 .needed_headroom = GSWIP_RX_HEADER_LEN,
106};
107
108MODULE_DESCRIPTION("DSA tag driver for Lantiq / Intel GSWIP switches");
109MODULE_LICENSE("GPL");
110MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_GSWIP, GSWIP_NAME);
111
112module_dsa_tag_driver(gswip_netdev_ops);