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_LEGACY_FCS_NAME "brcm-legacy-fcs"
19 #define BRCM_PREPEND_NAME "brcm-prepend"
20
21 /* Legacy Broadcom tag (6 bytes) */
22 #define BRCM_LEG_TAG_LEN 6
23
24 /* Type fields */
25 /* 1st byte in the tag */
26 #define BRCM_LEG_TYPE_HI 0x88
27 /* 2nd byte in the tag */
28 #define BRCM_LEG_TYPE_LO 0x74
29
30 /* Tag fields */
31 /* 3rd byte in the tag */
32 #define BRCM_LEG_UNICAST (0 << 5)
33 #define BRCM_LEG_MULTICAST (1 << 5)
34 #define BRCM_LEG_EGRESS (2 << 5)
35 #define BRCM_LEG_INGRESS (3 << 5)
36 #define BRCM_LEG_LEN_HI(x) (((x) >> 8) & 0x7)
37
38 /* 4th byte in the tag */
39 #define BRCM_LEG_LEN_LO(x) ((x) & 0xff)
40
41 /* 6th byte in the tag */
42 #define BRCM_LEG_PORT_ID (0xf)
43
44 /* Newer Broadcom tag (4 bytes) */
45 #define BRCM_TAG_LEN 4
46
47 /* Tag is constructed and deconstructed using byte by byte access
48 * because the tag is placed after the MAC Source Address, which does
49 * not make it 4-bytes aligned, so this might cause unaligned accesses
50 * on most systems where this is used.
51 */
52
53 /* Ingress and egress opcodes */
54 #define BRCM_OPCODE_SHIFT 5
55 #define BRCM_OPCODE_MASK 0x7
56
57 /* Ingress fields */
58 /* 1st byte in the tag */
59 #define BRCM_IG_TC_SHIFT 2
60 #define BRCM_IG_TC_MASK 0x7
61 /* 2nd byte in the tag */
62 #define BRCM_IG_TE_MASK 0x3
63 #define BRCM_IG_TS_SHIFT 7
64 /* 3rd byte in the tag */
65 #define BRCM_IG_DSTMAP2_MASK 1
66 #define BRCM_IG_DSTMAP1_MASK 0xff
67
68 /* Egress fields */
69
70 /* 2nd byte in the tag */
71 #define BRCM_EG_CID_MASK 0xff
72
73 /* 3rd byte in the tag */
74 #define BRCM_EG_RC_MASK 0xff
75 #define BRCM_EG_RC_RSVD (3 << 6)
76 #define BRCM_EG_RC_EXCEPTION (1 << 5)
77 #define BRCM_EG_RC_PROT_SNOOP (1 << 4)
78 #define BRCM_EG_RC_PROT_TERM (1 << 3)
79 #define BRCM_EG_RC_SWITCH (1 << 2)
80 #define BRCM_EG_RC_MAC_LEARN (1 << 1)
81 #define BRCM_EG_RC_MIRROR (1 << 0)
82 #define BRCM_EG_TC_SHIFT 5
83 #define BRCM_EG_TC_MASK 0x7
84 #define BRCM_EG_PID_MASK 0x1f
85
86 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
87 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
88
brcm_tag_xmit_ll(struct sk_buff * skb,struct net_device * dev,unsigned int offset)89 static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
90 struct net_device *dev,
91 unsigned int offset)
92 {
93 struct dsa_port *dp = dsa_user_to_port(dev);
94 u16 queue = skb_get_queue_mapping(skb);
95 u16 port_mask;
96 u8 *brcm_tag;
97
98 /* The Ethernet switch we are interfaced with needs packets to be at
99 * least 64 bytes (including FCS) otherwise they will be discarded when
100 * they enter the switch port logic. When Broadcom tags are enabled, we
101 * need to make sure that packets are at least 68 bytes
102 * (including FCS and tag) because the length verification is done after
103 * the Broadcom tag is stripped off the ingress packet.
104 *
105 * Free the SKB on error.
106 */
107 if (skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN))
108 return NULL;
109
110 skb_push(skb, BRCM_TAG_LEN);
111
112 if (offset)
113 dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
114
115 brcm_tag = skb->data + offset;
116
117 /* Set the ingress opcode, traffic class, tag enforcement is
118 * deprecated
119 */
120 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
121 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
122 brcm_tag[1] = 0;
123 port_mask = dsa_xmit_port_mask(skb, dev);
124 brcm_tag[2] = (port_mask >> 8) & BRCM_IG_DSTMAP2_MASK;
125 brcm_tag[3] = port_mask & BRCM_IG_DSTMAP1_MASK;
126
127 /* Now tell the conduit network device about the desired output queue
128 * as well
129 */
130 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
131
132 return skb;
133 }
134
135 /* Frames with this tag have one of these two layouts:
136 * -----------------------------------
137 * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
138 * -----------------------------------
139 * -----------------------------------
140 * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
141 * -----------------------------------
142 * In both cases, at receive time, skb->data points 2 bytes before the actual
143 * Ethernet type field and we have an offset of 4bytes between where skb->data
144 * and where the payload starts. So the same low-level receive function can be
145 * used.
146 */
brcm_tag_rcv_ll(struct sk_buff * skb,struct net_device * dev,unsigned int offset)147 static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
148 struct net_device *dev,
149 unsigned int offset)
150 {
151 int source_port;
152 u8 *brcm_tag;
153
154 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN))) {
155 kfree_skb(skb);
156 return NULL;
157 }
158
159 brcm_tag = skb->data - offset;
160
161 /* The opcode should never be different than 0b000 */
162 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK)) {
163 kfree_skb(skb);
164 return NULL;
165 }
166
167 /* We should never see a reserved reason code without knowing how to
168 * handle it
169 */
170 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD)) {
171 kfree_skb(skb);
172 return NULL;
173 }
174
175 /* Locate which port this is coming from */
176 source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
177
178 skb->dev = dsa_conduit_find_user(dev, 0, source_port);
179 if (!skb->dev) {
180 kfree_skb(skb);
181 return NULL;
182 }
183
184 /* Remove Broadcom tag and update checksum */
185 skb_pull_rcsum(skb, BRCM_TAG_LEN);
186
187 if (likely(!is_link_local_ether_addr(eth_hdr(skb)->h_dest)))
188 dsa_default_offload_fwd_mark(skb);
189
190 return skb;
191 }
192 #endif
193
194 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
brcm_tag_xmit(struct sk_buff * skb,struct net_device * dev)195 static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
196 struct net_device *dev)
197 {
198 /* Build the tag after the MAC Source Address */
199 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
200 }
201
202
brcm_tag_rcv(struct sk_buff * skb,struct net_device * dev)203 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
204 {
205 struct sk_buff *nskb;
206
207 /* skb->data points to the EtherType, the tag is right before it */
208 nskb = brcm_tag_rcv_ll(skb, dev, 2);
209 if (!nskb)
210 return nskb;
211
212 dsa_strip_etype_header(skb, BRCM_TAG_LEN);
213
214 return nskb;
215 }
216
217 static const struct dsa_device_ops brcm_netdev_ops = {
218 .name = BRCM_NAME,
219 .proto = DSA_TAG_PROTO_BRCM,
220 .xmit = brcm_tag_xmit,
221 .rcv = brcm_tag_rcv,
222 .needed_headroom = BRCM_TAG_LEN,
223 };
224
225 DSA_TAG_DRIVER(brcm_netdev_ops);
226 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM, BRCM_NAME);
227 #endif
228
229 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) || \
230 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS)
brcm_leg_tag_rcv(struct sk_buff * skb,struct net_device * dev)231 static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
232 struct net_device *dev)
233 {
234 int len = BRCM_LEG_TAG_LEN;
235 int source_port;
236 __be16 *proto;
237 u8 *brcm_tag;
238
239 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_TAG_LEN + VLAN_HLEN))) {
240 kfree_skb(skb);
241 return NULL;
242 }
243
244 brcm_tag = dsa_etype_header_pos_rx(skb);
245 proto = (__be16 *)(brcm_tag + BRCM_LEG_TAG_LEN);
246
247 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
248
249 skb->dev = dsa_conduit_find_user(dev, 0, source_port);
250 if (!skb->dev) {
251 kfree_skb(skb);
252 return NULL;
253 }
254
255 /* The internal switch in BCM63XX SoCs always tags on egress on the CPU
256 * port. We use VID 0 internally for untagged traffic, so strip the tag
257 * if the TCI field is all 0, and keep it otherwise to also retain
258 * e.g. 802.1p tagged packets.
259 */
260 if (proto[0] == htons(ETH_P_8021Q) && proto[1] == 0)
261 len += VLAN_HLEN;
262
263 /* Remove Broadcom tag and update checksum */
264 skb_pull_rcsum(skb, len);
265
266 if (likely(!is_link_local_ether_addr(eth_hdr(skb)->h_dest)))
267 dsa_default_offload_fwd_mark(skb);
268
269 dsa_strip_etype_header(skb, len);
270
271 return skb;
272 }
273 #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY || CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS */
274
275 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
brcm_leg_tag_xmit(struct sk_buff * skb,struct net_device * dev)276 static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
277 struct net_device *dev)
278 {
279 struct dsa_port *dp = dsa_user_to_port(dev);
280 u8 *brcm_tag;
281
282 /* The Ethernet switch we are interfaced with needs packets to be at
283 * least 64 bytes (including FCS) otherwise they will be discarded when
284 * they enter the switch port logic. When Broadcom tags are enabled, we
285 * need to make sure that packets are at least 70 bytes
286 * (including FCS and tag) because the length verification is done after
287 * the Broadcom tag is stripped off the ingress packet.
288 */
289 if (skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN))
290 return NULL;
291
292 skb_push(skb, BRCM_LEG_TAG_LEN);
293
294 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
295
296 brcm_tag = skb->data + 2 * ETH_ALEN;
297
298 /* Broadcom tag type */
299 brcm_tag[0] = BRCM_LEG_TYPE_HI;
300 brcm_tag[1] = BRCM_LEG_TYPE_LO;
301
302 /* Broadcom tag value */
303 brcm_tag[2] = BRCM_LEG_EGRESS;
304 brcm_tag[3] = 0;
305 brcm_tag[4] = 0;
306 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
307
308 return skb;
309 }
310
311 static const struct dsa_device_ops brcm_legacy_netdev_ops = {
312 .name = BRCM_LEGACY_NAME,
313 .proto = DSA_TAG_PROTO_BRCM_LEGACY,
314 .xmit = brcm_leg_tag_xmit,
315 .rcv = brcm_leg_tag_rcv,
316 .needed_headroom = BRCM_LEG_TAG_LEN,
317 };
318
319 DSA_TAG_DRIVER(brcm_legacy_netdev_ops);
320 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY, BRCM_LEGACY_NAME);
321 #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */
322
323 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS)
brcm_leg_fcs_tag_xmit(struct sk_buff * skb,struct net_device * dev)324 static struct sk_buff *brcm_leg_fcs_tag_xmit(struct sk_buff *skb,
325 struct net_device *dev)
326 {
327 struct dsa_port *dp = dsa_user_to_port(dev);
328 unsigned int fcs_len;
329 __le32 fcs_val;
330 u8 *brcm_tag;
331
332 /* The Ethernet switch we are interfaced with needs packets to be at
333 * least 64 bytes (including FCS) otherwise they will be discarded when
334 * they enter the switch port logic. When Broadcom tags are enabled, we
335 * need to make sure that packets are at least 70 bytes (including FCS
336 * and tag) because the length verification is done after the Broadcom
337 * tag is stripped off the ingress packet.
338 */
339 if (skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN))
340 return NULL;
341
342 fcs_len = skb->len;
343 fcs_val = cpu_to_le32(crc32_le(~0, skb->data, fcs_len) ^ ~0);
344
345 skb_push(skb, BRCM_LEG_TAG_LEN);
346
347 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
348
349 brcm_tag = skb->data + 2 * ETH_ALEN;
350
351 /* Broadcom tag type */
352 brcm_tag[0] = BRCM_LEG_TYPE_HI;
353 brcm_tag[1] = BRCM_LEG_TYPE_LO;
354
355 /* Broadcom tag value */
356 brcm_tag[2] = BRCM_LEG_EGRESS | BRCM_LEG_LEN_HI(fcs_len);
357 brcm_tag[3] = BRCM_LEG_LEN_LO(fcs_len);
358 brcm_tag[4] = 0;
359 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
360
361 /* Original FCS value */
362 if (skb_pad(skb, ETH_FCS_LEN))
363 return NULL;
364
365 skb_put_data(skb, &fcs_val, ETH_FCS_LEN);
366
367 return skb;
368 }
369
370 static const struct dsa_device_ops brcm_legacy_fcs_netdev_ops = {
371 .name = BRCM_LEGACY_FCS_NAME,
372 .proto = DSA_TAG_PROTO_BRCM_LEGACY_FCS,
373 .xmit = brcm_leg_fcs_tag_xmit,
374 .rcv = brcm_leg_tag_rcv,
375 .needed_headroom = BRCM_LEG_TAG_LEN,
376 };
377
378 DSA_TAG_DRIVER(brcm_legacy_fcs_netdev_ops);
379 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY_FCS, BRCM_LEGACY_FCS_NAME);
380 #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS */
381
382 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
brcm_tag_xmit_prepend(struct sk_buff * skb,struct net_device * dev)383 static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
384 struct net_device *dev)
385 {
386 /* tag is prepended to the packet */
387 return brcm_tag_xmit_ll(skb, dev, 0);
388 }
389
brcm_tag_rcv_prepend(struct sk_buff * skb,struct net_device * dev)390 static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
391 struct net_device *dev)
392 {
393 /* tag is prepended to the packet */
394 return brcm_tag_rcv_ll(skb, dev, ETH_HLEN);
395 }
396
397 static const struct dsa_device_ops brcm_prepend_netdev_ops = {
398 .name = BRCM_PREPEND_NAME,
399 .proto = DSA_TAG_PROTO_BRCM_PREPEND,
400 .xmit = brcm_tag_xmit_prepend,
401 .rcv = brcm_tag_rcv_prepend,
402 .needed_headroom = BRCM_TAG_LEN,
403 };
404
405 DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
406 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND, BRCM_PREPEND_NAME);
407 #endif
408
409 static struct dsa_tag_driver *dsa_tag_driver_array[] = {
410 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
411 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
412 #endif
413 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
414 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
415 #endif
416 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS)
417 &DSA_TAG_DRIVER_NAME(brcm_legacy_fcs_netdev_ops),
418 #endif
419 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
420 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
421 #endif
422 };
423
424 module_dsa_tag_drivers(dsa_tag_driver_array);
425
426 MODULE_DESCRIPTION("DSA tag driver for Broadcom switches using in-frame headers");
427 MODULE_LICENSE("GPL");
428