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/if_vlan.h>
11 #include <linux/list.h>
12 #include <linux/slab.h>
16 /* Legacy Broadcom tag (6 bytes) */
17 #define BRCM_LEG_TAG_LEN 6
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
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)
32 /* 6th byte in the tag */
33 #define BRCM_LEG_PORT_ID (0xf)
35 /* Newer Broadcom tag (4 bytes) */
36 #define BRCM_TAG_LEN 4
38 /* Tag is constructed and deconstructed 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.
44 /* Ingress and egress opcodes */
45 #define BRCM_OPCODE_SHIFT 5
46 #define BRCM_OPCODE_MASK 0x7
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
61 /* 2nd byte in the tag */
62 #define BRCM_EG_CID_MASK 0xff
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
77 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
78 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
80 static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
81 struct net_device *dev,
84 struct dsa_port *dp = dsa_slave_to_port(dev);
85 u16 queue = skb_get_queue_mapping(skb);
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.
95 * Let dsa_slave_xmit() free the SKB
97 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
100 skb_push(skb, BRCM_TAG_LEN);
103 dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
105 brcm_tag = skb->data + offset;
107 /* Set the ingress opcode, traffic class, tag enforcement is
110 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
111 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
115 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
116 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
118 /* Now tell the master network device about the desired output queue
121 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
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
138 static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
139 struct net_device *dev,
145 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
148 brcm_tag = skb->data - offset;
150 /* The opcode should never be different than 0b000 */
151 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
154 /* We should never see a reserved reason code without knowing how to
157 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
160 /* Locate which port this is coming from */
161 source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
163 skb->dev = dsa_master_find_slave(dev, 0, source_port);
167 /* Remove Broadcom tag and update checksum */
168 skb_pull_rcsum(skb, BRCM_TAG_LEN);
170 dsa_default_offload_fwd_mark(skb);
176 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
177 static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
178 struct net_device *dev)
180 /* Build the tag after the MAC Source Address */
181 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
185 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
187 struct sk_buff *nskb;
189 /* skb->data points to the EtherType, the tag is right before it */
190 nskb = brcm_tag_rcv_ll(skb, dev, 2);
194 dsa_strip_etype_header(skb, BRCM_TAG_LEN);
199 static const struct dsa_device_ops brcm_netdev_ops = {
201 .proto = DSA_TAG_PROTO_BRCM,
202 .xmit = brcm_tag_xmit,
204 .needed_headroom = BRCM_TAG_LEN,
207 DSA_TAG_DRIVER(brcm_netdev_ops);
208 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
211 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
212 static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
213 struct net_device *dev)
215 struct dsa_port *dp = dsa_slave_to_port(dev);
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.
225 * Let dsa_slave_xmit() free the SKB
227 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
230 skb_push(skb, BRCM_LEG_TAG_LEN);
232 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
234 brcm_tag = skb->data + 2 * ETH_ALEN;
236 /* Broadcom tag type */
237 brcm_tag[0] = BRCM_LEG_TYPE_HI;
238 brcm_tag[1] = BRCM_LEG_TYPE_LO;
240 /* Broadcom tag value */
241 brcm_tag[2] = BRCM_LEG_EGRESS;
244 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
249 static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
250 struct net_device *dev)
252 int len = BRCM_LEG_TAG_LEN;
256 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
259 brcm_tag = dsa_etype_header_pos_rx(skb);
261 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
263 skb->dev = dsa_master_find_slave(dev, 0, source_port);
267 /* VLAN tag is added by BCM63xx internal switch */
268 if (netdev_uses_dsa(skb->dev))
271 /* Remove Broadcom tag and update checksum */
272 skb_pull_rcsum(skb, len);
274 dsa_default_offload_fwd_mark(skb);
276 dsa_strip_etype_header(skb, 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");