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_SHIFT 1
52 #define GSWIP_TX_PORT_MAP_MASK GENMASK(6, 1)
53
54 #define GSWIP_RX_HEADER_LEN 8
55
56 /* special tag in RX path header */
57 /* Byte 7 */
58 #define GSWIP_RX_SPPID_SHIFT 4
59 #define GSWIP_RX_SPPID_MASK GENMASK(6, 4)
60
gswip_tag_xmit(struct sk_buff * skb,struct net_device * dev)61 static struct sk_buff *gswip_tag_xmit(struct sk_buff *skb,
62 struct net_device *dev)
63 {
64 struct dsa_port *dp = dsa_slave_to_port(dev);
65 u8 *gswip_tag;
66
67 skb_push(skb, GSWIP_TX_HEADER_LEN);
68
69 gswip_tag = skb->data;
70 gswip_tag[0] = GSWIP_TX_SLPID_CPU;
71 gswip_tag[1] = GSWIP_TX_DPID_ELAN;
72 gswip_tag[2] = GSWIP_TX_PORT_MAP_EN | GSWIP_TX_PORT_MAP_SEL;
73 gswip_tag[3] = BIT(dp->index + GSWIP_TX_PORT_MAP_SHIFT) & GSWIP_TX_PORT_MAP_MASK;
74 gswip_tag[3] |= GSWIP_TX_DPID_EN;
75
76 return skb;
77 }
78
gswip_tag_rcv(struct sk_buff * skb,struct net_device * dev)79 static struct sk_buff *gswip_tag_rcv(struct sk_buff *skb,
80 struct net_device *dev)
81 {
82 int port;
83 u8 *gswip_tag;
84
85 if (unlikely(!pskb_may_pull(skb, GSWIP_RX_HEADER_LEN)))
86 return NULL;
87
88 gswip_tag = skb->data - ETH_HLEN;
89
90 /* Get source port information */
91 port = (gswip_tag[7] & GSWIP_RX_SPPID_MASK) >> GSWIP_RX_SPPID_SHIFT;
92 skb->dev = dsa_master_find_slave(dev, 0, port);
93 if (!skb->dev)
94 return NULL;
95
96 /* remove GSWIP tag */
97 skb_pull_rcsum(skb, GSWIP_RX_HEADER_LEN);
98
99 return skb;
100 }
101
102 static const struct dsa_device_ops gswip_netdev_ops = {
103 .name = GSWIP_NAME,
104 .proto = DSA_TAG_PROTO_GSWIP,
105 .xmit = gswip_tag_xmit,
106 .rcv = gswip_tag_rcv,
107 .needed_headroom = GSWIP_RX_HEADER_LEN,
108 };
109
110 MODULE_LICENSE("GPL");
111 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_GSWIP, GSWIP_NAME);
112
113 module_dsa_tag_driver(gswip_netdev_ops);
114