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5037d532 FF |
1 | /* |
2 | * Broadcom tag support | |
3 | * | |
4 | * Copyright (C) 2014 Broadcom Corporation | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/etherdevice.h> | |
13 | #include <linux/list.h> | |
5037d532 FF |
14 | #include <linux/slab.h> |
15 | #include "dsa_priv.h" | |
16 | ||
17 | /* This tag length is 4 bytes, older ones were 6 bytes, we do not | |
18 | * handle them | |
19 | */ | |
20 | #define BRCM_TAG_LEN 4 | |
21 | ||
22 | /* Tag is constructed and desconstructed using byte by byte access | |
23 | * because the tag is placed after the MAC Source Address, which does | |
24 | * not make it 4-bytes aligned, so this might cause unaligned accesses | |
25 | * on most systems where this is used. | |
26 | */ | |
27 | ||
28 | /* Ingress and egress opcodes */ | |
29 | #define BRCM_OPCODE_SHIFT 5 | |
30 | #define BRCM_OPCODE_MASK 0x7 | |
31 | ||
32 | /* Ingress fields */ | |
33 | /* 1st byte in the tag */ | |
34 | #define BRCM_IG_TC_SHIFT 2 | |
35 | #define BRCM_IG_TC_MASK 0x7 | |
36 | /* 2nd byte in the tag */ | |
37 | #define BRCM_IG_TE_MASK 0x3 | |
38 | #define BRCM_IG_TS_SHIFT 7 | |
39 | /* 3rd byte in the tag */ | |
40 | #define BRCM_IG_DSTMAP2_MASK 1 | |
41 | #define BRCM_IG_DSTMAP1_MASK 0xff | |
42 | ||
43 | /* Egress fields */ | |
44 | ||
45 | /* 2nd byte in the tag */ | |
46 | #define BRCM_EG_CID_MASK 0xff | |
47 | ||
48 | /* 3rd byte in the tag */ | |
49 | #define BRCM_EG_RC_MASK 0xff | |
50 | #define BRCM_EG_RC_RSVD (3 << 6) | |
51 | #define BRCM_EG_RC_EXCEPTION (1 << 5) | |
52 | #define BRCM_EG_RC_PROT_SNOOP (1 << 4) | |
53 | #define BRCM_EG_RC_PROT_TERM (1 << 3) | |
54 | #define BRCM_EG_RC_SWITCH (1 << 2) | |
55 | #define BRCM_EG_RC_MAC_LEARN (1 << 1) | |
56 | #define BRCM_EG_RC_MIRROR (1 << 0) | |
57 | #define BRCM_EG_TC_SHIFT 5 | |
58 | #define BRCM_EG_TC_MASK 0x7 | |
59 | #define BRCM_EG_PID_MASK 0x1f | |
60 | ||
4ed70ce9 | 61 | static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev) |
5037d532 FF |
62 | { |
63 | struct dsa_slave_priv *p = netdev_priv(dev); | |
64 | u8 *brcm_tag; | |
65 | ||
5037d532 FF |
66 | if (skb_cow_head(skb, BRCM_TAG_LEN) < 0) |
67 | goto out_free; | |
68 | ||
69 | skb_push(skb, BRCM_TAG_LEN); | |
70 | ||
71 | memmove(skb->data, skb->data + BRCM_TAG_LEN, 2 * ETH_ALEN); | |
72 | ||
73 | /* Build the tag after the MAC Source Address */ | |
74 | brcm_tag = skb->data + 2 * ETH_ALEN; | |
75 | ||
76 | /* Set the ingress opcode, traffic class, tag enforcment is | |
77 | * deprecated | |
78 | */ | |
79 | brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) | | |
80 | ((skb->priority << BRCM_IG_TC_SHIFT) & BRCM_IG_TC_MASK); | |
81 | brcm_tag[1] = 0; | |
82 | brcm_tag[2] = 0; | |
83 | if (p->port == 8) | |
84 | brcm_tag[2] = BRCM_IG_DSTMAP2_MASK; | |
85 | brcm_tag[3] = (1 << p->port) & BRCM_IG_DSTMAP1_MASK; | |
86 | ||
4ed70ce9 | 87 | return skb; |
5037d532 FF |
88 | |
89 | out_free: | |
90 | kfree_skb(skb); | |
4ed70ce9 | 91 | return NULL; |
5037d532 FF |
92 | } |
93 | ||
94 | static int brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev, | |
95 | struct packet_type *pt, struct net_device *orig_dev) | |
96 | { | |
97 | struct dsa_switch_tree *dst = dev->dsa_ptr; | |
98 | struct dsa_switch *ds; | |
99 | int source_port; | |
100 | u8 *brcm_tag; | |
101 | ||
102 | if (unlikely(dst == NULL)) | |
103 | goto out_drop; | |
104 | ||
105 | ds = dst->ds[0]; | |
106 | ||
107 | skb = skb_unshare(skb, GFP_ATOMIC); | |
108 | if (skb == NULL) | |
109 | goto out; | |
110 | ||
111 | if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN))) | |
112 | goto out_drop; | |
113 | ||
114 | /* skb->data points to the EtherType, the tag is right before it */ | |
115 | brcm_tag = skb->data - 2; | |
116 | ||
117 | /* The opcode should never be different than 0b000 */ | |
118 | if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK)) | |
119 | goto out_drop; | |
120 | ||
121 | /* We should never see a reserved reason code without knowing how to | |
122 | * handle it | |
123 | */ | |
124 | WARN_ON(brcm_tag[2] & BRCM_EG_RC_RSVD); | |
125 | ||
126 | /* Locate which port this is coming from */ | |
127 | source_port = brcm_tag[3] & BRCM_EG_PID_MASK; | |
128 | ||
129 | /* Validate port against switch setup, either the port is totally */ | |
130 | if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) | |
131 | goto out_drop; | |
132 | ||
133 | /* Remove Broadcom tag and update checksum */ | |
134 | skb_pull_rcsum(skb, BRCM_TAG_LEN); | |
135 | ||
136 | /* Move the Ethernet DA and SA */ | |
137 | memmove(skb->data - ETH_HLEN, | |
138 | skb->data - ETH_HLEN - BRCM_TAG_LEN, | |
139 | 2 * ETH_ALEN); | |
140 | ||
141 | skb_push(skb, ETH_HLEN); | |
142 | skb->pkt_type = PACKET_HOST; | |
143 | skb->dev = ds->ports[source_port]; | |
144 | skb->protocol = eth_type_trans(skb, skb->dev); | |
145 | ||
146 | skb->dev->stats.rx_packets++; | |
147 | skb->dev->stats.rx_bytes += skb->len; | |
148 | ||
149 | netif_receive_skb(skb); | |
150 | ||
151 | return 0; | |
152 | ||
153 | out_drop: | |
154 | kfree_skb(skb); | |
155 | out: | |
156 | return 0; | |
157 | } | |
158 | ||
159 | const struct dsa_device_ops brcm_netdev_ops = { | |
160 | .xmit = brcm_tag_xmit, | |
161 | .rcv = brcm_tag_rcv, | |
162 | }; |