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 deconstructed 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 dsa_alloc_etype_header(skb, BRCM_TAG_LEN); 103 104 brcm_tag = skb->data + offset; 105 106 /* Set the ingress opcode, traffic class, tag enforcement 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 unsigned int offset) 140 { 141 int source_port; 142 u8 *brcm_tag; 143 144 if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN))) 145 return NULL; 146 147 brcm_tag = skb->data - offset; 148 149 /* The opcode should never be different than 0b000 */ 150 if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK)) 151 return NULL; 152 153 /* We should never see a reserved reason code without knowing how to 154 * handle it 155 */ 156 if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD)) 157 return NULL; 158 159 /* Locate which port this is coming from */ 160 source_port = brcm_tag[3] & BRCM_EG_PID_MASK; 161 162 skb->dev = dsa_master_find_slave(dev, 0, source_port); 163 if (!skb->dev) 164 return NULL; 165 166 /* Remove Broadcom tag and update checksum */ 167 skb_pull_rcsum(skb, BRCM_TAG_LEN); 168 169 dsa_default_offload_fwd_mark(skb); 170 171 return skb; 172 } 173 #endif 174 175 #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) 178 { 179 /* Build the tag after the MAC Source Address */ 180 return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN); 181 } 182 183 184 static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev) 185 { 186 struct sk_buff *nskb; 187 188 /* skb->data points to the EtherType, the tag is right before it */ 189 nskb = brcm_tag_rcv_ll(skb, dev, 2); 190 if (!nskb) 191 return nskb; 192 193 dsa_strip_etype_header(skb, BRCM_TAG_LEN); 194 195 return nskb; 196 } 197 198 static const struct dsa_device_ops brcm_netdev_ops = { 199 .name = "brcm", 200 .proto = DSA_TAG_PROTO_BRCM, 201 .xmit = brcm_tag_xmit, 202 .rcv = brcm_tag_rcv, 203 .needed_headroom = BRCM_TAG_LEN, 204 }; 205 206 DSA_TAG_DRIVER(brcm_netdev_ops); 207 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM); 208 #endif 209 210 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) 211 static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb, 212 struct net_device *dev) 213 { 214 struct dsa_port *dp = dsa_slave_to_port(dev); 215 u8 *brcm_tag; 216 217 /* The Ethernet switch we are interfaced with needs packets to be at 218 * least 64 bytes (including FCS) otherwise they will be discarded when 219 * they enter the switch port logic. When Broadcom tags are enabled, we 220 * need to make sure that packets are at least 70 bytes 221 * (including FCS and tag) because the length verification is done after 222 * the Broadcom tag is stripped off the ingress packet. 223 * 224 * Let dsa_slave_xmit() free the SKB 225 */ 226 if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false)) 227 return NULL; 228 229 skb_push(skb, BRCM_LEG_TAG_LEN); 230 231 dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN); 232 233 brcm_tag = skb->data + 2 * ETH_ALEN; 234 235 /* Broadcom tag type */ 236 brcm_tag[0] = BRCM_LEG_TYPE_HI; 237 brcm_tag[1] = BRCM_LEG_TYPE_LO; 238 239 /* Broadcom tag value */ 240 brcm_tag[2] = BRCM_LEG_EGRESS; 241 brcm_tag[3] = 0; 242 brcm_tag[4] = 0; 243 brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID; 244 245 return skb; 246 } 247 248 static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, 249 struct net_device *dev) 250 { 251 int source_port; 252 u8 *brcm_tag; 253 254 if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID))) 255 return NULL; 256 257 brcm_tag = dsa_etype_header_pos_rx(skb); 258 259 source_port = brcm_tag[5] & BRCM_LEG_PORT_ID; 260 261 skb->dev = dsa_master_find_slave(dev, 0, source_port); 262 if (!skb->dev) 263 return NULL; 264 265 /* Remove Broadcom tag and update checksum */ 266 skb_pull_rcsum(skb, BRCM_LEG_TAG_LEN); 267 268 dsa_default_offload_fwd_mark(skb); 269 270 dsa_strip_etype_header(skb, BRCM_LEG_TAG_LEN); 271 272 return skb; 273 } 274 275 static const struct dsa_device_ops brcm_legacy_netdev_ops = { 276 .name = "brcm-legacy", 277 .proto = DSA_TAG_PROTO_BRCM_LEGACY, 278 .xmit = brcm_leg_tag_xmit, 279 .rcv = brcm_leg_tag_rcv, 280 .needed_headroom = BRCM_LEG_TAG_LEN, 281 }; 282 283 DSA_TAG_DRIVER(brcm_legacy_netdev_ops); 284 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY); 285 #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */ 286 287 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 288 static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb, 289 struct net_device *dev) 290 { 291 /* tag is prepended to the packet */ 292 return brcm_tag_xmit_ll(skb, dev, 0); 293 } 294 295 static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb, 296 struct net_device *dev) 297 { 298 /* tag is prepended to the packet */ 299 return brcm_tag_rcv_ll(skb, dev, ETH_HLEN); 300 } 301 302 static const struct dsa_device_ops brcm_prepend_netdev_ops = { 303 .name = "brcm-prepend", 304 .proto = DSA_TAG_PROTO_BRCM_PREPEND, 305 .xmit = brcm_tag_xmit_prepend, 306 .rcv = brcm_tag_rcv_prepend, 307 .needed_headroom = BRCM_TAG_LEN, 308 }; 309 310 DSA_TAG_DRIVER(brcm_prepend_netdev_ops); 311 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND); 312 #endif 313 314 static struct dsa_tag_driver *dsa_tag_driver_array[] = { 315 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) 316 &DSA_TAG_DRIVER_NAME(brcm_netdev_ops), 317 #endif 318 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) 319 &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops), 320 #endif 321 #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) 322 &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops), 323 #endif 324 }; 325 326 module_dsa_tag_drivers(dsa_tag_driver_array); 327 328 MODULE_LICENSE("GPL"); 329