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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Broadcom tag support
4 *
5 * Copyright (C) 2014 Broadcom Corporation
6 */
7
8#include <linux/dsa/brcm.h>
9#include <linux/etherdevice.h>
10#include <linux/list.h>
11#include <linux/slab.h>
12
13#include "dsa_priv.h"
14
15/* Legacy Broadcom tag (6 bytes) */
16#define BRCM_LEG_TAG_LEN 6
17
18/* Type fields */
19/* 1st byte in the tag */
20#define BRCM_LEG_TYPE_HI 0x88
21/* 2nd byte in the tag */
22#define BRCM_LEG_TYPE_LO 0x74
23
24/* Tag fields */
25/* 3rd byte in the tag */
26#define BRCM_LEG_UNICAST (0 << 5)
27#define BRCM_LEG_MULTICAST (1 << 5)
28#define BRCM_LEG_EGRESS (2 << 5)
29#define BRCM_LEG_INGRESS (3 << 5)
30
31/* 6th byte in the tag */
32#define BRCM_LEG_PORT_ID (0xf)
33
34/* Newer Broadcom tag (4 bytes) */
35#define BRCM_TAG_LEN 4
36
37/* Tag is constructed and deconstructed using byte by byte access
38 * because the tag is placed after the MAC Source Address, which does
39 * not make it 4-bytes aligned, so this might cause unaligned accesses
40 * on most systems where this is used.
41 */
42
43/* Ingress and egress opcodes */
44#define BRCM_OPCODE_SHIFT 5
45#define BRCM_OPCODE_MASK 0x7
46
47/* Ingress fields */
48/* 1st byte in the tag */
49#define BRCM_IG_TC_SHIFT 2
50#define BRCM_IG_TC_MASK 0x7
51/* 2nd byte in the tag */
52#define BRCM_IG_TE_MASK 0x3
53#define BRCM_IG_TS_SHIFT 7
54/* 3rd byte in the tag */
55#define BRCM_IG_DSTMAP2_MASK 1
56#define BRCM_IG_DSTMAP1_MASK 0xff
57
58/* Egress fields */
59
60/* 2nd byte in the tag */
61#define BRCM_EG_CID_MASK 0xff
62
63/* 3rd byte in the tag */
64#define BRCM_EG_RC_MASK 0xff
65#define BRCM_EG_RC_RSVD (3 << 6)
66#define BRCM_EG_RC_EXCEPTION (1 << 5)
67#define BRCM_EG_RC_PROT_SNOOP (1 << 4)
68#define BRCM_EG_RC_PROT_TERM (1 << 3)
69#define BRCM_EG_RC_SWITCH (1 << 2)
70#define BRCM_EG_RC_MAC_LEARN (1 << 1)
71#define BRCM_EG_RC_MIRROR (1 << 0)
72#define BRCM_EG_TC_SHIFT 5
73#define BRCM_EG_TC_MASK 0x7
74#define BRCM_EG_PID_MASK 0x1f
75
76#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
77 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
78
79static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
80 struct net_device *dev,
81 unsigned int offset)
82{
83 struct dsa_port *dp = dsa_slave_to_port(dev);
84 u16 queue = skb_get_queue_mapping(skb);
85 u8 *brcm_tag;
86
87 /* The Ethernet switch we are interfaced with needs packets to be at
88 * least 64 bytes (including FCS) otherwise they will be discarded when
89 * they enter the switch port logic. When Broadcom tags are enabled, we
90 * need to make sure that packets are at least 68 bytes
91 * (including FCS and tag) because the length verification is done after
92 * the Broadcom tag is stripped off the ingress packet.
93 *
94 * Let dsa_slave_xmit() free the SKB
95 */
96 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
97 return NULL;
98
99 skb_push(skb, BRCM_TAG_LEN);
100
101 if (offset)
102 dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
103
104 brcm_tag = skb->data + offset;
105
106 /* Set the ingress opcode, traffic class, tag enforcement is
107 * deprecated
108 */
109 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
110 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
111 brcm_tag[1] = 0;
112 brcm_tag[2] = 0;
113 if (dp->index == 8)
114 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
115 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
116
117 /* Now tell the master network device about the desired output queue
118 * as well
119 */
120 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
121
122 return skb;
123}
124
125/* Frames with this tag have one of these two layouts:
126 * -----------------------------------
127 * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
128 * -----------------------------------
129 * -----------------------------------
130 * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
131 * -----------------------------------
132 * In both cases, at receive time, skb->data points 2 bytes before the actual
133 * Ethernet type field and we have an offset of 4bytes between where skb->data
134 * and where the payload starts. So the same low-level receive function can be
135 * used.
136 */
137static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
138 struct net_device *dev,
139 unsigned int offset)
140{
141 int source_port;
142 u8 *brcm_tag;
143
144 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
145 return NULL;
146
147 brcm_tag = skb->data - offset;
148
149 /* The opcode should never be different than 0b000 */
150 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
151 return NULL;
152
153 /* We should never see a reserved reason code without knowing how to
154 * handle it
155 */
156 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
157 return NULL;
158
159 /* Locate which port this is coming from */
160 source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
161
162 skb->dev = dsa_master_find_slave(dev, 0, source_port);
163 if (!skb->dev)
164 return NULL;
165
166 /* Remove Broadcom tag and update checksum */
167 skb_pull_rcsum(skb, BRCM_TAG_LEN);
168
169 dsa_default_offload_fwd_mark(skb);
170
171 return skb;
172}
173#endif
174
175#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
176static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
177 struct net_device *dev)
178{
179 /* Build the tag after the MAC Source Address */
180 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
181}
182
183
184static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
185{
186 struct sk_buff *nskb;
187
188 /* skb->data points to the EtherType, the tag is right before it */
189 nskb = brcm_tag_rcv_ll(skb, dev, 2);
190 if (!nskb)
191 return nskb;
192
193 dsa_strip_etype_header(skb, BRCM_TAG_LEN);
194
195 return nskb;
196}
197
198static const struct dsa_device_ops brcm_netdev_ops = {
199 .name = "brcm",
200 .proto = DSA_TAG_PROTO_BRCM,
201 .xmit = brcm_tag_xmit,
202 .rcv = brcm_tag_rcv,
203 .needed_headroom = BRCM_TAG_LEN,
204};
205
206DSA_TAG_DRIVER(brcm_netdev_ops);
207MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
208#endif
209
210#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
211static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
212 struct net_device *dev)
213{
214 struct dsa_port *dp = dsa_slave_to_port(dev);
215 u8 *brcm_tag;
216
217 /* The Ethernet switch we are interfaced with needs packets to be at
218 * least 64 bytes (including FCS) otherwise they will be discarded when
219 * they enter the switch port logic. When Broadcom tags are enabled, we
220 * need to make sure that packets are at least 70 bytes
221 * (including FCS and tag) because the length verification is done after
222 * the Broadcom tag is stripped off the ingress packet.
223 *
224 * Let dsa_slave_xmit() free the SKB
225 */
226 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
227 return NULL;
228
229 skb_push(skb, BRCM_LEG_TAG_LEN);
230
231 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
232
233 brcm_tag = skb->data + 2 * ETH_ALEN;
234
235 /* Broadcom tag type */
236 brcm_tag[0] = BRCM_LEG_TYPE_HI;
237 brcm_tag[1] = BRCM_LEG_TYPE_LO;
238
239 /* Broadcom tag value */
240 brcm_tag[2] = BRCM_LEG_EGRESS;
241 brcm_tag[3] = 0;
242 brcm_tag[4] = 0;
243 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
244
245 return skb;
246}
247
248static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
249 struct net_device *dev)
250{
251 int source_port;
252 u8 *brcm_tag;
253
254 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
255 return NULL;
256
257 brcm_tag = dsa_etype_header_pos_rx(skb);
258
259 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
260
261 skb->dev = dsa_master_find_slave(dev, 0, source_port);
262 if (!skb->dev)
263 return NULL;
264
265 /* Remove Broadcom tag and update checksum */
266 skb_pull_rcsum(skb, BRCM_LEG_TAG_LEN);
267
268 dsa_default_offload_fwd_mark(skb);
269
270 dsa_strip_etype_header(skb, BRCM_LEG_TAG_LEN);
271
272 return skb;
273}
274
275static const struct dsa_device_ops brcm_legacy_netdev_ops = {
276 .name = "brcm-legacy",
277 .proto = DSA_TAG_PROTO_BRCM_LEGACY,
278 .xmit = brcm_leg_tag_xmit,
279 .rcv = brcm_leg_tag_rcv,
280 .needed_headroom = BRCM_LEG_TAG_LEN,
281};
282
283DSA_TAG_DRIVER(brcm_legacy_netdev_ops);
284MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY);
285#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */
286
287#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
288static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
289 struct net_device *dev)
290{
291 /* tag is prepended to the packet */
292 return brcm_tag_xmit_ll(skb, dev, 0);
293}
294
295static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
296 struct net_device *dev)
297{
298 /* tag is prepended to the packet */
299 return brcm_tag_rcv_ll(skb, dev, ETH_HLEN);
300}
301
302static const struct dsa_device_ops brcm_prepend_netdev_ops = {
303 .name = "brcm-prepend",
304 .proto = DSA_TAG_PROTO_BRCM_PREPEND,
305 .xmit = brcm_tag_xmit_prepend,
306 .rcv = brcm_tag_rcv_prepend,
307 .needed_headroom = BRCM_TAG_LEN,
308};
309
310DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
311MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND);
312#endif
313
314static struct dsa_tag_driver *dsa_tag_driver_array[] = {
315#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
316 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
317#endif
318#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
319 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
320#endif
321#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
322 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
323#endif
324};
325
326module_dsa_tag_drivers(dsa_tag_driver_array);
327
328MODULE_LICENSE("GPL");