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 /* This tag length is 4 bytes, older ones were 6 bytes, we do not
18 #define BRCM_TAG_LEN 4
20 /* Tag is constructed and desconstructed using byte by byte access
21 * because the tag is placed after the MAC Source Address, which does
22 * not make it 4-bytes aligned, so this might cause unaligned accesses
23 * on most systems where this is used.
26 /* Ingress and egress opcodes */
27 #define BRCM_OPCODE_SHIFT 5
28 #define BRCM_OPCODE_MASK 0x7
31 /* 1st byte in the tag */
32 #define BRCM_IG_TC_SHIFT 2
33 #define BRCM_IG_TC_MASK 0x7
34 /* 2nd byte in the tag */
35 #define BRCM_IG_TE_MASK 0x3
36 #define BRCM_IG_TS_SHIFT 7
37 /* 3rd byte in the tag */
38 #define BRCM_IG_DSTMAP2_MASK 1
39 #define BRCM_IG_DSTMAP1_MASK 0xff
43 /* 2nd byte in the tag */
44 #define BRCM_EG_CID_MASK 0xff
46 /* 3rd byte in the tag */
47 #define BRCM_EG_RC_MASK 0xff
48 #define BRCM_EG_RC_RSVD (3 << 6)
49 #define BRCM_EG_RC_EXCEPTION (1 << 5)
50 #define BRCM_EG_RC_PROT_SNOOP (1 << 4)
51 #define BRCM_EG_RC_PROT_TERM (1 << 3)
52 #define BRCM_EG_RC_SWITCH (1 << 2)
53 #define BRCM_EG_RC_MAC_LEARN (1 << 1)
54 #define BRCM_EG_RC_MIRROR (1 << 0)
55 #define BRCM_EG_TC_SHIFT 5
56 #define BRCM_EG_TC_MASK 0x7
57 #define BRCM_EG_PID_MASK 0x1f
59 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
60 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
62 static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
63 struct net_device *dev,
66 struct dsa_port *dp = dsa_slave_to_port(dev);
67 u16 queue = skb_get_queue_mapping(skb);
70 /* The Ethernet switch we are interfaced with needs packets to be at
71 * least 64 bytes (including FCS) otherwise they will be discarded when
72 * they enter the switch port logic. When Broadcom tags are enabled, we
73 * need to make sure that packets are at least 68 bytes
74 * (including FCS and tag) because the length verification is done after
75 * the Broadcom tag is stripped off the ingress packet.
77 * Let dsa_slave_xmit() free the SKB
79 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
82 skb_push(skb, BRCM_TAG_LEN);
85 memmove(skb->data, skb->data + BRCM_TAG_LEN, offset);
87 brcm_tag = skb->data + offset;
89 /* Set the ingress opcode, traffic class, tag enforcment is
92 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
93 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
97 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
98 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
100 /* Now tell the master network device about the desired output queue
103 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
108 /* Frames with this tag have one of these two layouts:
109 * -----------------------------------
110 * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
111 * -----------------------------------
112 * -----------------------------------
113 * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
114 * -----------------------------------
115 * In both cases, at receive time, skb->data points 2 bytes before the actual
116 * Ethernet type field and we have an offset of 4bytes between where skb->data
117 * and where the payload starts. So the same low-level receive function can be
120 static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
121 struct net_device *dev,
122 struct packet_type *pt,
128 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
131 brcm_tag = skb->data - offset;
133 /* The opcode should never be different than 0b000 */
134 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
137 /* We should never see a reserved reason code without knowing how to
140 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
143 /* Locate which port this is coming from */
144 source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
146 skb->dev = dsa_master_find_slave(dev, 0, source_port);
150 /* Remove Broadcom tag and update checksum */
151 skb_pull_rcsum(skb, BRCM_TAG_LEN);
153 skb->offload_fwd_mark = 1;
159 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
160 static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
161 struct net_device *dev)
163 /* Build the tag after the MAC Source Address */
164 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
168 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev,
169 struct packet_type *pt)
171 struct sk_buff *nskb;
173 /* skb->data points to the EtherType, the tag is right before it */
174 nskb = brcm_tag_rcv_ll(skb, dev, pt, 2);
178 /* Move the Ethernet DA and SA */
179 memmove(nskb->data - ETH_HLEN,
180 nskb->data - ETH_HLEN - BRCM_TAG_LEN,
186 static const struct dsa_device_ops brcm_netdev_ops = {
188 .proto = DSA_TAG_PROTO_BRCM,
189 .xmit = brcm_tag_xmit,
191 .overhead = BRCM_TAG_LEN,
194 DSA_TAG_DRIVER(brcm_netdev_ops);
195 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
198 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
199 static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
200 struct net_device *dev)
202 /* tag is prepended to the packet */
203 return brcm_tag_xmit_ll(skb, dev, 0);
206 static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
207 struct net_device *dev,
208 struct packet_type *pt)
210 /* tag is prepended to the packet */
211 return brcm_tag_rcv_ll(skb, dev, pt, ETH_HLEN);
214 static const struct dsa_device_ops brcm_prepend_netdev_ops = {
215 .name = "brcm-prepend",
216 .proto = DSA_TAG_PROTO_BRCM_PREPEND,
217 .xmit = brcm_tag_xmit_prepend,
218 .rcv = brcm_tag_rcv_prepend,
219 .overhead = BRCM_TAG_LEN,
222 DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
223 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND);
226 static struct dsa_tag_driver *dsa_tag_driver_array[] = {
227 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
228 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
230 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
231 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
235 module_dsa_tag_drivers(dsa_tag_driver_array);
237 MODULE_LICENSE("GPL");