1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com> 3 */ 4 #include <linux/if_vlan.h> 5 #include <linux/dsa/sja1105.h> 6 #include <linux/dsa/8021q.h> 7 #include <linux/packing.h> 8 #include "dsa_priv.h" 9 10 /* Similar to is_link_local_ether_addr(hdr->h_dest) but also covers PTP */ 11 static inline bool sja1105_is_link_local(const struct sk_buff *skb) 12 { 13 const struct ethhdr *hdr = eth_hdr(skb); 14 u64 dmac = ether_addr_to_u64(hdr->h_dest); 15 16 if (ntohs(hdr->h_proto) == ETH_P_SJA1105_META) 17 return false; 18 if ((dmac & SJA1105_LINKLOCAL_FILTER_A_MASK) == 19 SJA1105_LINKLOCAL_FILTER_A) 20 return true; 21 if ((dmac & SJA1105_LINKLOCAL_FILTER_B_MASK) == 22 SJA1105_LINKLOCAL_FILTER_B) 23 return true; 24 return false; 25 } 26 27 struct sja1105_meta { 28 u64 tstamp; 29 u64 dmac_byte_4; 30 u64 dmac_byte_3; 31 u64 source_port; 32 u64 switch_id; 33 }; 34 35 static void sja1105_meta_unpack(const struct sk_buff *skb, 36 struct sja1105_meta *meta) 37 { 38 u8 *buf = skb_mac_header(skb) + ETH_HLEN; 39 40 /* UM10944.pdf section 4.2.17 AVB Parameters: 41 * Structure of the meta-data follow-up frame. 42 * It is in network byte order, so there are no quirks 43 * while unpacking the meta frame. 44 * 45 * Also SJA1105 E/T only populates bits 23:0 of the timestamp 46 * whereas P/Q/R/S does 32 bits. Since the structure is the 47 * same and the E/T puts zeroes in the high-order byte, use 48 * a unified unpacking command for both device series. 49 */ 50 packing(buf, &meta->tstamp, 31, 0, 4, UNPACK, 0); 51 packing(buf + 4, &meta->dmac_byte_4, 7, 0, 1, UNPACK, 0); 52 packing(buf + 5, &meta->dmac_byte_3, 7, 0, 1, UNPACK, 0); 53 packing(buf + 6, &meta->source_port, 7, 0, 1, UNPACK, 0); 54 packing(buf + 7, &meta->switch_id, 7, 0, 1, UNPACK, 0); 55 } 56 57 static inline bool sja1105_is_meta_frame(const struct sk_buff *skb) 58 { 59 const struct ethhdr *hdr = eth_hdr(skb); 60 u64 smac = ether_addr_to_u64(hdr->h_source); 61 u64 dmac = ether_addr_to_u64(hdr->h_dest); 62 63 if (smac != SJA1105_META_SMAC) 64 return false; 65 if (dmac != SJA1105_META_DMAC) 66 return false; 67 if (ntohs(hdr->h_proto) != ETH_P_SJA1105_META) 68 return false; 69 return true; 70 } 71 72 static bool sja1105_can_use_vlan_as_tags(const struct sk_buff *skb) 73 { 74 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); 75 76 if (hdr->h_vlan_proto == htons(ETH_P_SJA1105)) 77 return true; 78 79 if (hdr->h_vlan_proto != htons(ETH_P_8021Q)) 80 return false; 81 82 return vid_is_dsa_8021q(ntohs(hdr->h_vlan_TCI) & VLAN_VID_MASK); 83 } 84 85 /* This is the first time the tagger sees the frame on RX. 86 * Figure out if we can decode it. 87 */ 88 static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev) 89 { 90 if (sja1105_can_use_vlan_as_tags(skb)) 91 return true; 92 if (sja1105_is_link_local(skb)) 93 return true; 94 if (sja1105_is_meta_frame(skb)) 95 return true; 96 return false; 97 } 98 99 /* Calls sja1105_port_deferred_xmit in sja1105_main.c */ 100 static struct sk_buff *sja1105_defer_xmit(struct sja1105_port *sp, 101 struct sk_buff *skb) 102 { 103 /* Increase refcount so the kfree_skb in dsa_slave_xmit 104 * won't really free the packet. 105 */ 106 skb_queue_tail(&sp->xmit_queue, skb_get(skb)); 107 kthread_queue_work(sp->xmit_worker, &sp->xmit_work); 108 109 return NULL; 110 } 111 112 static u16 sja1105_xmit_tpid(struct sja1105_port *sp) 113 { 114 return sp->xmit_tpid; 115 } 116 117 static struct sk_buff *sja1105_xmit(struct sk_buff *skb, 118 struct net_device *netdev) 119 { 120 struct dsa_port *dp = dsa_slave_to_port(netdev); 121 u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index); 122 u16 queue_mapping = skb_get_queue_mapping(skb); 123 u8 pcp = netdev_txq_to_tc(netdev, queue_mapping); 124 125 /* Transmitting management traffic does not rely upon switch tagging, 126 * but instead SPI-installed management routes. Part 2 of this 127 * is the .port_deferred_xmit driver callback. 128 */ 129 if (unlikely(sja1105_is_link_local(skb))) 130 return sja1105_defer_xmit(dp->priv, skb); 131 132 return dsa_8021q_xmit(skb, netdev, sja1105_xmit_tpid(dp->priv), 133 ((pcp << VLAN_PRIO_SHIFT) | tx_vid)); 134 } 135 136 static void sja1105_transfer_meta(struct sk_buff *skb, 137 const struct sja1105_meta *meta) 138 { 139 struct ethhdr *hdr = eth_hdr(skb); 140 141 hdr->h_dest[3] = meta->dmac_byte_3; 142 hdr->h_dest[4] = meta->dmac_byte_4; 143 SJA1105_SKB_CB(skb)->meta_tstamp = meta->tstamp; 144 } 145 146 /* This is a simple state machine which follows the hardware mechanism of 147 * generating RX timestamps: 148 * 149 * After each timestampable skb (all traffic for which send_meta1 and 150 * send_meta0 is true, aka all MAC-filtered link-local traffic) a meta frame 151 * containing a partial timestamp is immediately generated by the switch and 152 * sent as a follow-up to the link-local frame on the CPU port. 153 * 154 * The meta frames have no unique identifier (such as sequence number) by which 155 * one may pair them to the correct timestampable frame. 156 * Instead, the switch has internal logic that ensures no frames are sent on 157 * the CPU port between a link-local timestampable frame and its corresponding 158 * meta follow-up. It also ensures strict ordering between ports (lower ports 159 * have higher priority towards the CPU port). For this reason, a per-port 160 * data structure is not needed/desirable. 161 * 162 * This function pairs the link-local frame with its partial timestamp from the 163 * meta follow-up frame. The full timestamp will be reconstructed later in a 164 * work queue. 165 */ 166 static struct sk_buff 167 *sja1105_rcv_meta_state_machine(struct sk_buff *skb, 168 struct sja1105_meta *meta, 169 bool is_link_local, 170 bool is_meta) 171 { 172 struct sja1105_port *sp; 173 struct dsa_port *dp; 174 175 dp = dsa_slave_to_port(skb->dev); 176 sp = dp->priv; 177 178 /* Step 1: A timestampable frame was received. 179 * Buffer it until we get its meta frame. 180 */ 181 if (is_link_local) { 182 if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) 183 /* Do normal processing. */ 184 return skb; 185 186 spin_lock(&sp->data->meta_lock); 187 /* Was this a link-local frame instead of the meta 188 * that we were expecting? 189 */ 190 if (sp->data->stampable_skb) { 191 dev_err_ratelimited(dp->ds->dev, 192 "Expected meta frame, is %12llx " 193 "in the DSA master multicast filter?\n", 194 SJA1105_META_DMAC); 195 kfree_skb(sp->data->stampable_skb); 196 } 197 198 /* Hold a reference to avoid dsa_switch_rcv 199 * from freeing the skb. 200 */ 201 sp->data->stampable_skb = skb_get(skb); 202 spin_unlock(&sp->data->meta_lock); 203 204 /* Tell DSA we got nothing */ 205 return NULL; 206 207 /* Step 2: The meta frame arrived. 208 * Time to take the stampable skb out of the closet, annotate it 209 * with the partial timestamp, and pretend that we received it 210 * just now (basically masquerade the buffered frame as the meta 211 * frame, which serves no further purpose). 212 */ 213 } else if (is_meta) { 214 struct sk_buff *stampable_skb; 215 216 /* Drop the meta frame if we're not in the right state 217 * to process it. 218 */ 219 if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) 220 return NULL; 221 222 spin_lock(&sp->data->meta_lock); 223 224 stampable_skb = sp->data->stampable_skb; 225 sp->data->stampable_skb = NULL; 226 227 /* Was this a meta frame instead of the link-local 228 * that we were expecting? 229 */ 230 if (!stampable_skb) { 231 dev_err_ratelimited(dp->ds->dev, 232 "Unexpected meta frame\n"); 233 spin_unlock(&sp->data->meta_lock); 234 return NULL; 235 } 236 237 if (stampable_skb->dev != skb->dev) { 238 dev_err_ratelimited(dp->ds->dev, 239 "Meta frame on wrong port\n"); 240 spin_unlock(&sp->data->meta_lock); 241 return NULL; 242 } 243 244 /* Free the meta frame and give DSA the buffered stampable_skb 245 * for further processing up the network stack. 246 */ 247 kfree_skb(skb); 248 skb = stampable_skb; 249 sja1105_transfer_meta(skb, meta); 250 251 spin_unlock(&sp->data->meta_lock); 252 } 253 254 return skb; 255 } 256 257 static void sja1105_decode_subvlan(struct sk_buff *skb, u16 subvlan) 258 { 259 struct dsa_port *dp = dsa_slave_to_port(skb->dev); 260 struct sja1105_port *sp = dp->priv; 261 u16 vid = sp->subvlan_map[subvlan]; 262 u16 vlan_tci; 263 264 if (vid == VLAN_N_VID) 265 return; 266 267 vlan_tci = (skb->priority << VLAN_PRIO_SHIFT) | vid; 268 __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tci); 269 } 270 271 static struct sk_buff *sja1105_rcv(struct sk_buff *skb, 272 struct net_device *netdev, 273 struct packet_type *pt) 274 { 275 struct sja1105_meta meta = {0}; 276 int source_port, switch_id; 277 struct ethhdr *hdr; 278 u16 tpid, vid, tci; 279 bool is_link_local; 280 u16 subvlan = 0; 281 bool is_tagged; 282 bool is_meta; 283 284 hdr = eth_hdr(skb); 285 tpid = ntohs(hdr->h_proto); 286 is_tagged = (tpid == ETH_P_SJA1105 || tpid == ETH_P_8021Q); 287 is_link_local = sja1105_is_link_local(skb); 288 is_meta = sja1105_is_meta_frame(skb); 289 290 skb->offload_fwd_mark = 1; 291 292 if (is_tagged) { 293 /* Normal traffic path. */ 294 skb_push_rcsum(skb, ETH_HLEN); 295 __skb_vlan_pop(skb, &tci); 296 skb_pull_rcsum(skb, ETH_HLEN); 297 skb_reset_network_header(skb); 298 skb_reset_transport_header(skb); 299 300 vid = tci & VLAN_VID_MASK; 301 source_port = dsa_8021q_rx_source_port(vid); 302 switch_id = dsa_8021q_rx_switch_id(vid); 303 skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; 304 subvlan = dsa_8021q_rx_subvlan(vid); 305 } else if (is_link_local) { 306 /* Management traffic path. Switch embeds the switch ID and 307 * port ID into bytes of the destination MAC, courtesy of 308 * the incl_srcpt options. 309 */ 310 source_port = hdr->h_dest[3]; 311 switch_id = hdr->h_dest[4]; 312 /* Clear the DMAC bytes that were mangled by the switch */ 313 hdr->h_dest[3] = 0; 314 hdr->h_dest[4] = 0; 315 } else if (is_meta) { 316 sja1105_meta_unpack(skb, &meta); 317 source_port = meta.source_port; 318 switch_id = meta.switch_id; 319 } else { 320 return NULL; 321 } 322 323 skb->dev = dsa_master_find_slave(netdev, switch_id, source_port); 324 if (!skb->dev) { 325 netdev_warn(netdev, "Couldn't decode source port\n"); 326 return NULL; 327 } 328 329 if (subvlan) 330 sja1105_decode_subvlan(skb, subvlan); 331 332 return sja1105_rcv_meta_state_machine(skb, &meta, is_link_local, 333 is_meta); 334 } 335 336 static const struct dsa_device_ops sja1105_netdev_ops = { 337 .name = "sja1105", 338 .proto = DSA_TAG_PROTO_SJA1105, 339 .xmit = sja1105_xmit, 340 .rcv = sja1105_rcv, 341 .filter = sja1105_filter, 342 .overhead = VLAN_HLEN, 343 }; 344 345 MODULE_LICENSE("GPL v2"); 346 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SJA1105); 347 348 module_dsa_tag_driver(sja1105_netdev_ops); 349