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