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 "tag.h" 14 15 #define BRCM_NAME "brcm" 16 #define BRCM_LEGACY_NAME "brcm-legacy" 17 #define BRCM_PREPEND_NAME "brcm-prepend" 18 19 /* Legacy Broadcom tag (6 bytes) */ 20 #define BRCM_LEG_TAG_LEN 6 21 22 /* Type fields */ 23 /* 1st byte in the tag */ 24 #define BRCM_LEG_TYPE_HI 0x88 25 /* 2nd byte in the tag */ 26 #define BRCM_LEG_TYPE_LO 0x74 27 28 /* Tag fields */ 29 /* 3rd byte in the tag */ 30 #define BRCM_LEG_UNICAST (0 << 5) 31 #define BRCM_LEG_MULTICAST (1 << 5) 32 #define BRCM_LEG_EGRESS (2 << 5) 33 #define BRCM_LEG_INGRESS (3 << 5) 34 35 /* 6th byte in the tag */ 36 #define BRCM_LEG_PORT_ID (0xf) 37 38 /* Newer Broadcom tag (4 bytes) */ 39 #define BRCM_TAG_LEN 4 40 41 /* Tag is constructed and deconstructed using byte by byte access 42 * because the tag is placed after the MAC Source Address, which does 43 * not make it 4-bytes aligned, so this might cause unaligned accesses 44 * on most systems where this is used. 45 */ 46 47 /* Ingress and egress opcodes */ 48 #define BRCM_OPCODE_SHIFT 5 49 #define BRCM_OPCODE_MASK 0x7 50 51 /* Ingress fields */ 52 /* 1st byte in the tag */ 53 #define BRCM_IG_TC_SHIFT 2 54 #define BRCM_IG_TC_MASK 0x7 55 /* 2nd byte in the tag */ 56 #define BRCM_IG_TE_MASK 0x3 57 #define BRCM_IG_TS_SHIFT 7 58 /* 3rd byte in the tag */ 59 #define BRCM_IG_DSTMAP2_MASK 1 60 #define BRCM_IG_DSTMAP1_MASK 0xff 61 62 /* Egress fields */ 63 64 /* 2nd byte in the tag */ 65 #define BRCM_EG_CID_MASK 0xff 66 67 /* 3rd byte in the tag */ 68 #define BRCM_EG_RC_MASK 0xff 69 #define BRCM_EG_RC_RSVD (3 << 6) 70 #define BRCM_EG_RC_EXCEPTION (1 << 5) 71 #define BRCM_EG_RC_PROT_SNOOP (1 << 4) 72 #define BRCM_EG_RC_PROT_TERM (1 << 3) 73 #define BRCM_EG_RC_SWITCH (1 << 2) 74 #define BRCM_EG_RC_MAC_LEARN (1 << 1) 75 #define BRCM_EG_RC_MIRROR (1 << 0) 76 #define BRCM_EG_TC_SHIFT 5 77 #define BRCM_EG_TC_MASK 0x7 78 #define BRCM_EG_PID_MASK 0x1f 79 80 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \ 81 IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 82 83 static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, 84 struct net_device *dev, 85 unsigned int offset) 86 { 87 struct dsa_port *dp = dsa_slave_to_port(dev); 88 u16 queue = skb_get_queue_mapping(skb); 89 u8 *brcm_tag; 90 91 /* The Ethernet switch we are interfaced with needs packets to be at 92 * least 64 bytes (including FCS) otherwise they will be discarded when 93 * they enter the switch port logic. When Broadcom tags are enabled, we 94 * need to make sure that packets are at least 68 bytes 95 * (including FCS and tag) because the length verification is done after 96 * the Broadcom tag is stripped off the ingress packet. 97 * 98 * Let dsa_slave_xmit() free the SKB 99 */ 100 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false)) 101 return NULL; 102 103 skb_push(skb, BRCM_TAG_LEN); 104 105 if (offset) 106 dsa_alloc_etype_header(skb, BRCM_TAG_LEN); 107 108 brcm_tag = skb->data + offset; 109 110 /* Set the ingress opcode, traffic class, tag enforcement is 111 * deprecated 112 */ 113 brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) | 114 ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT); 115 brcm_tag[1] = 0; 116 brcm_tag[2] = 0; 117 if (dp->index == 8) 118 brcm_tag[2] = BRCM_IG_DSTMAP2_MASK; 119 brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK; 120 121 /* Now tell the master network device about the desired output queue 122 * as well 123 */ 124 skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue)); 125 126 return skb; 127 } 128 129 /* Frames with this tag have one of these two layouts: 130 * ----------------------------------- 131 * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM 132 * ----------------------------------- 133 * ----------------------------------- 134 * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND 135 * ----------------------------------- 136 * In both cases, at receive time, skb->data points 2 bytes before the actual 137 * Ethernet type field and we have an offset of 4bytes between where skb->data 138 * and where the payload starts. So the same low-level receive function can be 139 * used. 140 */ 141 static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb, 142 struct net_device *dev, 143 unsigned int offset) 144 { 145 int source_port; 146 u8 *brcm_tag; 147 148 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN))) 149 return NULL; 150 151 brcm_tag = skb->data - offset; 152 153 /* The opcode should never be different than 0b000 */ 154 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK)) 155 return NULL; 156 157 /* We should never see a reserved reason code without knowing how to 158 * handle it 159 */ 160 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD)) 161 return NULL; 162 163 /* Locate which port this is coming from */ 164 source_port = brcm_tag[3] & BRCM_EG_PID_MASK; 165 166 skb->dev = dsa_master_find_slave(dev, 0, source_port); 167 if (!skb->dev) 168 return NULL; 169 170 /* Remove Broadcom tag and update checksum */ 171 skb_pull_rcsum(skb, BRCM_TAG_LEN); 172 173 dsa_default_offload_fwd_mark(skb); 174 175 return skb; 176 } 177 #endif 178 179 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) 180 static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb, 181 struct net_device *dev) 182 { 183 /* Build the tag after the MAC Source Address */ 184 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN); 185 } 186 187 188 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev) 189 { 190 struct sk_buff *nskb; 191 192 /* skb->data points to the EtherType, the tag is right before it */ 193 nskb = brcm_tag_rcv_ll(skb, dev, 2); 194 if (!nskb) 195 return nskb; 196 197 dsa_strip_etype_header(skb, BRCM_TAG_LEN); 198 199 return nskb; 200 } 201 202 static const struct dsa_device_ops brcm_netdev_ops = { 203 .name = BRCM_NAME, 204 .proto = DSA_TAG_PROTO_BRCM, 205 .xmit = brcm_tag_xmit, 206 .rcv = brcm_tag_rcv, 207 .needed_headroom = BRCM_TAG_LEN, 208 }; 209 210 DSA_TAG_DRIVER(brcm_netdev_ops); 211 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM, BRCM_NAME); 212 #endif 213 214 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) 215 static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb, 216 struct net_device *dev) 217 { 218 struct dsa_port *dp = dsa_slave_to_port(dev); 219 u8 *brcm_tag; 220 221 /* The Ethernet switch we are interfaced with needs packets to be at 222 * least 64 bytes (including FCS) otherwise they will be discarded when 223 * they enter the switch port logic. When Broadcom tags are enabled, we 224 * need to make sure that packets are at least 70 bytes 225 * (including FCS and tag) because the length verification is done after 226 * the Broadcom tag is stripped off the ingress packet. 227 * 228 * Let dsa_slave_xmit() free the SKB 229 */ 230 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false)) 231 return NULL; 232 233 skb_push(skb, BRCM_LEG_TAG_LEN); 234 235 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN); 236 237 brcm_tag = skb->data + 2 * ETH_ALEN; 238 239 /* Broadcom tag type */ 240 brcm_tag[0] = BRCM_LEG_TYPE_HI; 241 brcm_tag[1] = BRCM_LEG_TYPE_LO; 242 243 /* Broadcom tag value */ 244 brcm_tag[2] = BRCM_LEG_EGRESS; 245 brcm_tag[3] = 0; 246 brcm_tag[4] = 0; 247 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID; 248 249 return skb; 250 } 251 252 static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, 253 struct net_device *dev) 254 { 255 int source_port; 256 u8 *brcm_tag; 257 258 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID))) 259 return NULL; 260 261 brcm_tag = dsa_etype_header_pos_rx(skb); 262 263 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID; 264 265 skb->dev = dsa_master_find_slave(dev, 0, source_port); 266 if (!skb->dev) 267 return NULL; 268 269 /* Remove Broadcom tag and update checksum */ 270 skb_pull_rcsum(skb, BRCM_LEG_TAG_LEN); 271 272 dsa_default_offload_fwd_mark(skb); 273 274 dsa_strip_etype_header(skb, BRCM_LEG_TAG_LEN); 275 276 return skb; 277 } 278 279 static const struct dsa_device_ops brcm_legacy_netdev_ops = { 280 .name = BRCM_LEGACY_NAME, 281 .proto = DSA_TAG_PROTO_BRCM_LEGACY, 282 .xmit = brcm_leg_tag_xmit, 283 .rcv = brcm_leg_tag_rcv, 284 .needed_headroom = BRCM_LEG_TAG_LEN, 285 }; 286 287 DSA_TAG_DRIVER(brcm_legacy_netdev_ops); 288 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY, BRCM_LEGACY_NAME); 289 #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */ 290 291 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 292 static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb, 293 struct net_device *dev) 294 { 295 /* tag is prepended to the packet */ 296 return brcm_tag_xmit_ll(skb, dev, 0); 297 } 298 299 static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb, 300 struct net_device *dev) 301 { 302 /* tag is prepended to the packet */ 303 return brcm_tag_rcv_ll(skb, dev, ETH_HLEN); 304 } 305 306 static const struct dsa_device_ops brcm_prepend_netdev_ops = { 307 .name = BRCM_PREPEND_NAME, 308 .proto = DSA_TAG_PROTO_BRCM_PREPEND, 309 .xmit = brcm_tag_xmit_prepend, 310 .rcv = brcm_tag_rcv_prepend, 311 .needed_headroom = BRCM_TAG_LEN, 312 }; 313 314 DSA_TAG_DRIVER(brcm_prepend_netdev_ops); 315 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND, BRCM_PREPEND_NAME); 316 #endif 317 318 static struct dsa_tag_driver *dsa_tag_driver_array[] = { 319 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) 320 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops), 321 #endif 322 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) 323 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops), 324 #endif 325 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 326 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops), 327 #endif 328 }; 329 330 module_dsa_tag_drivers(dsa_tag_driver_array); 331 332 MODULE_LICENSE("GPL"); 333