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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/if_vlan.h>
11#include <linux/list.h>
12#include <linux/slab.h>
13
14#include "tag.h"
15
16#define BRCM_NAME "brcm"
17#define BRCM_LEGACY_NAME "brcm-legacy"
18#define BRCM_PREPEND_NAME "brcm-prepend"
19
20/* Legacy Broadcom tag (6 bytes) */
21#define BRCM_LEG_TAG_LEN 6
22
23/* Type fields */
24/* 1st byte in the tag */
25#define BRCM_LEG_TYPE_HI 0x88
26/* 2nd byte in the tag */
27#define BRCM_LEG_TYPE_LO 0x74
28
29/* Tag fields */
30/* 3rd byte in the tag */
31#define BRCM_LEG_UNICAST (0 << 5)
32#define BRCM_LEG_MULTICAST (1 << 5)
33#define BRCM_LEG_EGRESS (2 << 5)
34#define BRCM_LEG_INGRESS (3 << 5)
35
36/* 6th byte in the tag */
37#define BRCM_LEG_PORT_ID (0xf)
38
39/* Newer Broadcom tag (4 bytes) */
40#define BRCM_TAG_LEN 4
41
42/* Tag is constructed and deconstructed using byte by byte access
43 * because the tag is placed after the MAC Source Address, which does
44 * not make it 4-bytes aligned, so this might cause unaligned accesses
45 * on most systems where this is used.
46 */
47
48/* Ingress and egress opcodes */
49#define BRCM_OPCODE_SHIFT 5
50#define BRCM_OPCODE_MASK 0x7
51
52/* Ingress fields */
53/* 1st byte in the tag */
54#define BRCM_IG_TC_SHIFT 2
55#define BRCM_IG_TC_MASK 0x7
56/* 2nd byte in the tag */
57#define BRCM_IG_TE_MASK 0x3
58#define BRCM_IG_TS_SHIFT 7
59/* 3rd byte in the tag */
60#define BRCM_IG_DSTMAP2_MASK 1
61#define BRCM_IG_DSTMAP1_MASK 0xff
62
63/* Egress fields */
64
65/* 2nd byte in the tag */
66#define BRCM_EG_CID_MASK 0xff
67
68/* 3rd byte in the tag */
69#define BRCM_EG_RC_MASK 0xff
70#define BRCM_EG_RC_RSVD (3 << 6)
71#define BRCM_EG_RC_EXCEPTION (1 << 5)
72#define BRCM_EG_RC_PROT_SNOOP (1 << 4)
73#define BRCM_EG_RC_PROT_TERM (1 << 3)
74#define BRCM_EG_RC_SWITCH (1 << 2)
75#define BRCM_EG_RC_MAC_LEARN (1 << 1)
76#define BRCM_EG_RC_MIRROR (1 << 0)
77#define BRCM_EG_TC_SHIFT 5
78#define BRCM_EG_TC_MASK 0x7
79#define BRCM_EG_PID_MASK 0x1f
80
81#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
82 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
83
84static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
85 struct net_device *dev,
86 unsigned int offset)
87{
88 struct dsa_port *dp = dsa_user_to_port(dev);
89 u16 queue = skb_get_queue_mapping(skb);
90 u8 *brcm_tag;
91
92 /* The Ethernet switch we are interfaced with needs packets to be at
93 * least 64 bytes (including FCS) otherwise they will be discarded when
94 * they enter the switch port logic. When Broadcom tags are enabled, we
95 * need to make sure that packets are at least 68 bytes
96 * (including FCS and tag) because the length verification is done after
97 * the Broadcom tag is stripped off the ingress packet.
98 *
99 * Let dsa_user_xmit() free the SKB
100 */
101 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
102 return NULL;
103
104 skb_push(skb, BRCM_TAG_LEN);
105
106 if (offset)
107 dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
108
109 brcm_tag = skb->data + offset;
110
111 /* Set the ingress opcode, traffic class, tag enforcement is
112 * deprecated
113 */
114 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
115 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
116 brcm_tag[1] = 0;
117 brcm_tag[2] = 0;
118 if (dp->index == 8)
119 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
120 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
121
122 /* Now tell the conduit network device about the desired output queue
123 * as well
124 */
125 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
126
127 return skb;
128}
129
130/* Frames with this tag have one of these two layouts:
131 * -----------------------------------
132 * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
133 * -----------------------------------
134 * -----------------------------------
135 * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
136 * -----------------------------------
137 * In both cases, at receive time, skb->data points 2 bytes before the actual
138 * Ethernet type field and we have an offset of 4bytes between where skb->data
139 * and where the payload starts. So the same low-level receive function can be
140 * used.
141 */
142static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
143 struct net_device *dev,
144 unsigned int offset)
145{
146 int source_port;
147 u8 *brcm_tag;
148
149 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
150 return NULL;
151
152 brcm_tag = skb->data - offset;
153
154 /* The opcode should never be different than 0b000 */
155 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
156 return NULL;
157
158 /* We should never see a reserved reason code without knowing how to
159 * handle it
160 */
161 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
162 return NULL;
163
164 /* Locate which port this is coming from */
165 source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
166
167 skb->dev = dsa_conduit_find_user(dev, 0, source_port);
168 if (!skb->dev)
169 return NULL;
170
171 /* Remove Broadcom tag and update checksum */
172 skb_pull_rcsum(skb, BRCM_TAG_LEN);
173
174 dsa_default_offload_fwd_mark(skb);
175
176 return skb;
177}
178#endif
179
180#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
181static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
182 struct net_device *dev)
183{
184 /* Build the tag after the MAC Source Address */
185 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
186}
187
188
189static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
190{
191 struct sk_buff *nskb;
192
193 /* skb->data points to the EtherType, the tag is right before it */
194 nskb = brcm_tag_rcv_ll(skb, dev, 2);
195 if (!nskb)
196 return nskb;
197
198 dsa_strip_etype_header(skb, BRCM_TAG_LEN);
199
200 return nskb;
201}
202
203static const struct dsa_device_ops brcm_netdev_ops = {
204 .name = BRCM_NAME,
205 .proto = DSA_TAG_PROTO_BRCM,
206 .xmit = brcm_tag_xmit,
207 .rcv = brcm_tag_rcv,
208 .needed_headroom = BRCM_TAG_LEN,
209};
210
211DSA_TAG_DRIVER(brcm_netdev_ops);
212MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM, BRCM_NAME);
213#endif
214
215#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
216static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
217 struct net_device *dev)
218{
219 struct dsa_port *dp = dsa_user_to_port(dev);
220 u8 *brcm_tag;
221
222 /* The Ethernet switch we are interfaced with needs packets to be at
223 * least 64 bytes (including FCS) otherwise they will be discarded when
224 * they enter the switch port logic. When Broadcom tags are enabled, we
225 * need to make sure that packets are at least 70 bytes
226 * (including FCS and tag) because the length verification is done after
227 * the Broadcom tag is stripped off the ingress packet.
228 *
229 * Let dsa_user_xmit() free the SKB
230 */
231 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
232 return NULL;
233
234 skb_push(skb, BRCM_LEG_TAG_LEN);
235
236 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
237
238 brcm_tag = skb->data + 2 * ETH_ALEN;
239
240 /* Broadcom tag type */
241 brcm_tag[0] = BRCM_LEG_TYPE_HI;
242 brcm_tag[1] = BRCM_LEG_TYPE_LO;
243
244 /* Broadcom tag value */
245 brcm_tag[2] = BRCM_LEG_EGRESS;
246 brcm_tag[3] = 0;
247 brcm_tag[4] = 0;
248 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
249
250 return skb;
251}
252
253static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
254 struct net_device *dev)
255{
256 int len = BRCM_LEG_TAG_LEN;
257 int source_port;
258 u8 *brcm_tag;
259
260 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
261 return NULL;
262
263 brcm_tag = dsa_etype_header_pos_rx(skb);
264
265 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
266
267 skb->dev = dsa_conduit_find_user(dev, 0, source_port);
268 if (!skb->dev)
269 return NULL;
270
271 /* VLAN tag is added by BCM63xx internal switch */
272 if (netdev_uses_dsa(skb->dev))
273 len += VLAN_HLEN;
274
275 /* Remove Broadcom tag and update checksum */
276 skb_pull_rcsum(skb, len);
277
278 dsa_default_offload_fwd_mark(skb);
279
280 dsa_strip_etype_header(skb, len);
281
282 return skb;
283}
284
285static const struct dsa_device_ops brcm_legacy_netdev_ops = {
286 .name = BRCM_LEGACY_NAME,
287 .proto = DSA_TAG_PROTO_BRCM_LEGACY,
288 .xmit = brcm_leg_tag_xmit,
289 .rcv = brcm_leg_tag_rcv,
290 .needed_headroom = BRCM_LEG_TAG_LEN,
291};
292
293DSA_TAG_DRIVER(brcm_legacy_netdev_ops);
294MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY, BRCM_LEGACY_NAME);
295#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */
296
297#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
298static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
299 struct net_device *dev)
300{
301 /* tag is prepended to the packet */
302 return brcm_tag_xmit_ll(skb, dev, 0);
303}
304
305static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
306 struct net_device *dev)
307{
308 /* tag is prepended to the packet */
309 return brcm_tag_rcv_ll(skb, dev, ETH_HLEN);
310}
311
312static const struct dsa_device_ops brcm_prepend_netdev_ops = {
313 .name = BRCM_PREPEND_NAME,
314 .proto = DSA_TAG_PROTO_BRCM_PREPEND,
315 .xmit = brcm_tag_xmit_prepend,
316 .rcv = brcm_tag_rcv_prepend,
317 .needed_headroom = BRCM_TAG_LEN,
318};
319
320DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
321MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND, BRCM_PREPEND_NAME);
322#endif
323
324static struct dsa_tag_driver *dsa_tag_driver_array[] = {
325#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
326 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
327#endif
328#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
329 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
330#endif
331#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
332 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
333#endif
334};
335
336module_dsa_tag_drivers(dsa_tag_driver_array);
337
338MODULE_DESCRIPTION("DSA tag driver for Broadcom switches using in-frame headers");
339MODULE_LICENSE("GPL");