1 // SPDX-License-Identifier: GPL-2.0+
5 * Copyright (C) 2014 Broadcom Corporation
8 #include <linux/dsa/brcm.h>
9 #include <linux/etherdevice.h>
10 #include <linux/list.h>
11 #include <linux/slab.h>
15 /* Legacy Broadcom tag (6 bytes) */
16 #define BRCM_LEG_TAG_LEN 6
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
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)
31 /* 6th byte in the tag */
32 #define BRCM_LEG_PORT_ID (0xf)
34 /* Newer Broadcom tag (4 bytes) */
35 #define BRCM_TAG_LEN 4
37 /* Tag is constructed and desconstructed 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.
43 /* Ingress and egress opcodes */
44 #define BRCM_OPCODE_SHIFT 5
45 #define BRCM_OPCODE_MASK 0x7
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
60 /* 2nd byte in the tag */
61 #define BRCM_EG_CID_MASK 0xff
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
76 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
77 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
79 static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
80 struct net_device *dev,
83 struct dsa_port *dp = dsa_slave_to_port(dev);
84 u16 queue = skb_get_queue_mapping(skb);
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.
94 * Let dsa_slave_xmit() free the SKB
96 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
99 skb_push(skb, BRCM_TAG_LEN);
102 memmove(skb->data, skb->data + BRCM_TAG_LEN, offset);
104 brcm_tag = skb->data + offset;
106 /* Set the ingress opcode, traffic class, tag enforcment is
109 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
110 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
114 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
115 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
117 /* Now tell the master network device about the desired output queue
120 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
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
137 static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
138 struct net_device *dev,
144 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
147 brcm_tag = skb->data - offset;
149 /* The opcode should never be different than 0b000 */
150 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
153 /* We should never see a reserved reason code without knowing how to
156 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
159 /* Locate which port this is coming from */
160 source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
162 skb->dev = dsa_master_find_slave(dev, 0, source_port);
166 /* Remove Broadcom tag and update checksum */
167 skb_pull_rcsum(skb, BRCM_TAG_LEN);
169 dsa_default_offload_fwd_mark(skb);
175 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
176 static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
177 struct net_device *dev)
179 /* Build the tag after the MAC Source Address */
180 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
184 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
186 struct sk_buff *nskb;
188 /* skb->data points to the EtherType, the tag is right before it */
189 nskb = brcm_tag_rcv_ll(skb, dev, 2);
193 /* Move the Ethernet DA and SA */
194 memmove(nskb->data - ETH_HLEN,
195 nskb->data - ETH_HLEN - BRCM_TAG_LEN,
201 static const struct dsa_device_ops brcm_netdev_ops = {
203 .proto = DSA_TAG_PROTO_BRCM,
204 .xmit = brcm_tag_xmit,
206 .needed_headroom = BRCM_TAG_LEN,
209 DSA_TAG_DRIVER(brcm_netdev_ops);
210 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
213 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
214 static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
215 struct net_device *dev)
217 struct dsa_port *dp = dsa_slave_to_port(dev);
220 /* The Ethernet switch we are interfaced with needs packets to be at
221 * least 64 bytes (including FCS) otherwise they will be discarded when
222 * they enter the switch port logic. When Broadcom tags are enabled, we
223 * need to make sure that packets are at least 70 bytes
224 * (including FCS and tag) because the length verification is done after
225 * the Broadcom tag is stripped off the ingress packet.
227 * Let dsa_slave_xmit() free the SKB
229 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
232 skb_push(skb, BRCM_LEG_TAG_LEN);
234 memmove(skb->data, skb->data + BRCM_LEG_TAG_LEN, 2 * ETH_ALEN);
236 brcm_tag = skb->data + 2 * ETH_ALEN;
238 /* Broadcom tag type */
239 brcm_tag[0] = BRCM_LEG_TYPE_HI;
240 brcm_tag[1] = BRCM_LEG_TYPE_LO;
242 /* Broadcom tag value */
243 brcm_tag[2] = BRCM_LEG_EGRESS;
246 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
251 static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
252 struct net_device *dev)
257 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
260 brcm_tag = skb->data - 2;
262 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
264 skb->dev = dsa_master_find_slave(dev, 0, source_port);
268 /* Remove Broadcom tag and update checksum */
269 skb_pull_rcsum(skb, BRCM_LEG_TAG_LEN);
271 dsa_default_offload_fwd_mark(skb);
273 /* Move the Ethernet DA and SA */
274 memmove(skb->data - ETH_HLEN,
275 skb->data - ETH_HLEN - BRCM_LEG_TAG_LEN,
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,
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 */
293 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
294 static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
295 struct net_device *dev)
297 /* tag is prepended to the packet */
298 return brcm_tag_xmit_ll(skb, dev, 0);
301 static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
302 struct net_device *dev)
304 /* tag is prepended to the packet */
305 return brcm_tag_rcv_ll(skb, dev, ETH_HLEN);
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,
316 DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
317 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND);
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),
324 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
325 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
327 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
328 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
332 module_dsa_tag_drivers(dsa_tag_driver_array);
334 MODULE_LICENSE("GPL");