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/list.h> 11 #include <linux/slab.h> 12 13 #include "dsa_priv.h" 14 15 /* Legacy Broadcom tag (6 bytes) */ 16 #define BRCM_LEG_TAG_LEN 6 17 18 /* Type fields */ 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 23 24 /* Tag fields */ 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) 30 31 /* 6th byte in the tag */ 32 #define BRCM_LEG_PORT_ID (0xf) 33 34 /* Newer Broadcom tag (4 bytes) */ 35 #define BRCM_TAG_LEN 4 36 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. 41 */ 42 43 /* Ingress and egress opcodes */ 44 #define BRCM_OPCODE_SHIFT 5 45 #define BRCM_OPCODE_MASK 0x7 46 47 /* Ingress fields */ 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 57 58 /* Egress fields */ 59 60 /* 2nd byte in the tag */ 61 #define BRCM_EG_CID_MASK 0xff 62 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 75 76 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \ 77 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 78 79 static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, 80 struct net_device *dev, 81 unsigned int offset) 82 { 83 struct dsa_port *dp = dsa_slave_to_port(dev); 84 u16 queue = skb_get_queue_mapping(skb); 85 u8 *brcm_tag; 86 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. 93 * 94 * Let dsa_slave_xmit() free the SKB 95 */ 96 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false)) 97 return NULL; 98 99 skb_push(skb, BRCM_TAG_LEN); 100 101 if (offset) 102 memmove(skb->data, skb->data + BRCM_TAG_LEN, offset); 103 104 brcm_tag = skb->data + offset; 105 106 /* Set the ingress opcode, traffic class, tag enforcment is 107 * deprecated 108 */ 109 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) | 110 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT); 111 brcm_tag[1] = 0; 112 brcm_tag[2] = 0; 113 if (dp->index == 8) 114 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK; 115 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK; 116 117 /* Now tell the master network device about the desired output queue 118 * as well 119 */ 120 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue)); 121 122 return skb; 123 } 124 125 /* 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 135 * used. 136 */ 137 static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb, 138 struct net_device *dev, 139 struct packet_type *pt, 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 skb->offload_fwd_mark = 1; 171 172 return skb; 173 } 174 #endif 175 176 #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) 179 { 180 /* Build the tag after the MAC Source Address */ 181 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN); 182 } 183 184 185 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev, 186 struct packet_type *pt) 187 { 188 struct sk_buff *nskb; 189 190 /* skb->data points to the EtherType, the tag is right before it */ 191 nskb = brcm_tag_rcv_ll(skb, dev, pt, 2); 192 if (!nskb) 193 return nskb; 194 195 /* Move the Ethernet DA and SA */ 196 memmove(nskb->data - ETH_HLEN, 197 nskb->data - ETH_HLEN - BRCM_TAG_LEN, 198 2 * ETH_ALEN); 199 200 return nskb; 201 } 202 203 static const struct dsa_device_ops brcm_netdev_ops = { 204 .name = "brcm", 205 .proto = DSA_TAG_PROTO_BRCM, 206 .xmit = brcm_tag_xmit, 207 .rcv = brcm_tag_rcv, 208 .needed_headroom = BRCM_TAG_LEN, 209 }; 210 211 DSA_TAG_DRIVER(brcm_netdev_ops); 212 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM); 213 #endif 214 215 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) 216 static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb, 217 struct net_device *dev) 218 { 219 struct dsa_port *dp = dsa_slave_to_port(dev); 220 u8 *brcm_tag; 221 222 /* The Ethernet switch we are interfaced with needs packets to be at 223 * least 64 bytes (including FCS) otherwise they will be discarded when 224 * they enter the switch port logic. When Broadcom tags are enabled, we 225 * need to make sure that packets are at least 70 bytes 226 * (including FCS and tag) because the length verification is done after 227 * the Broadcom tag is stripped off the ingress packet. 228 * 229 * Let dsa_slave_xmit() free the SKB 230 */ 231 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false)) 232 return NULL; 233 234 skb_push(skb, BRCM_LEG_TAG_LEN); 235 236 memmove(skb->data, skb->data + BRCM_LEG_TAG_LEN, 2 * ETH_ALEN); 237 238 brcm_tag = skb->data + 2 * ETH_ALEN; 239 240 /* Broadcom tag type */ 241 brcm_tag[0] = BRCM_LEG_TYPE_HI; 242 brcm_tag[1] = BRCM_LEG_TYPE_LO; 243 244 /* Broadcom tag value */ 245 brcm_tag[2] = BRCM_LEG_EGRESS; 246 brcm_tag[3] = 0; 247 brcm_tag[4] = 0; 248 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID; 249 250 return skb; 251 } 252 253 static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, 254 struct net_device *dev, 255 struct packet_type *pt) 256 { 257 int source_port; 258 u8 *brcm_tag; 259 260 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID))) 261 return NULL; 262 263 brcm_tag = skb->data - 2; 264 265 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID; 266 267 skb->dev = dsa_master_find_slave(dev, 0, source_port); 268 if (!skb->dev) 269 return NULL; 270 271 /* Remove Broadcom tag and update checksum */ 272 skb_pull_rcsum(skb, BRCM_LEG_TAG_LEN); 273 274 skb->offload_fwd_mark = 1; 275 276 /* Move the Ethernet DA and SA */ 277 memmove(skb->data - ETH_HLEN, 278 skb->data - ETH_HLEN - BRCM_LEG_TAG_LEN, 279 2 * ETH_ALEN); 280 281 return skb; 282 } 283 284 static const struct dsa_device_ops brcm_legacy_netdev_ops = { 285 .name = "brcm-legacy", 286 .proto = DSA_TAG_PROTO_BRCM_LEGACY, 287 .xmit = brcm_leg_tag_xmit, 288 .rcv = brcm_leg_tag_rcv, 289 .needed_headroom = BRCM_LEG_TAG_LEN, 290 }; 291 292 DSA_TAG_DRIVER(brcm_legacy_netdev_ops); 293 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY); 294 #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */ 295 296 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 297 static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb, 298 struct net_device *dev) 299 { 300 /* tag is prepended to the packet */ 301 return brcm_tag_xmit_ll(skb, dev, 0); 302 } 303 304 static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb, 305 struct net_device *dev, 306 struct packet_type *pt) 307 { 308 /* tag is prepended to the packet */ 309 return brcm_tag_rcv_ll(skb, dev, pt, ETH_HLEN); 310 } 311 312 static const struct dsa_device_ops brcm_prepend_netdev_ops = { 313 .name = "brcm-prepend", 314 .proto = DSA_TAG_PROTO_BRCM_PREPEND, 315 .xmit = brcm_tag_xmit_prepend, 316 .rcv = brcm_tag_rcv_prepend, 317 .needed_headroom = BRCM_TAG_LEN, 318 }; 319 320 DSA_TAG_DRIVER(brcm_prepend_netdev_ops); 321 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND); 322 #endif 323 324 static struct dsa_tag_driver *dsa_tag_driver_array[] = { 325 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) 326 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops), 327 #endif 328 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) 329 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops), 330 #endif 331 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 332 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops), 333 #endif 334 }; 335 336 module_dsa_tag_drivers(dsa_tag_driver_array); 337 338 MODULE_LICENSE("GPL"); 339