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 /* This is the first time the tagger sees the frame on RX. 73 * Figure out if we can decode it. 74 */ 75 static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev) 76 { 77 if (!dsa_port_is_vlan_filtering(dev->dsa_ptr)) 78 return true; 79 if (sja1105_is_link_local(skb)) 80 return true; 81 if (sja1105_is_meta_frame(skb)) 82 return true; 83 return false; 84 } 85 86 /* Calls sja1105_port_deferred_xmit in sja1105_main.c */ 87 static struct sk_buff *sja1105_defer_xmit(struct sja1105_port *sp, 88 struct sk_buff *skb) 89 { 90 /* Increase refcount so the kfree_skb in dsa_slave_xmit 91 * won't really free the packet. 92 */ 93 skb_queue_tail(&sp->xmit_queue, skb_get(skb)); 94 kthread_queue_work(sp->xmit_worker, &sp->xmit_work); 95 96 return NULL; 97 } 98 99 static struct sk_buff *sja1105_xmit(struct sk_buff *skb, 100 struct net_device *netdev) 101 { 102 struct dsa_port *dp = dsa_slave_to_port(netdev); 103 u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index); 104 u16 queue_mapping = skb_get_queue_mapping(skb); 105 u8 pcp = netdev_txq_to_tc(netdev, queue_mapping); 106 107 /* Transmitting management traffic does not rely upon switch tagging, 108 * but instead SPI-installed management routes. Part 2 of this 109 * is the .port_deferred_xmit driver callback. 110 */ 111 if (unlikely(sja1105_is_link_local(skb))) 112 return sja1105_defer_xmit(dp->priv, skb); 113 114 /* If we are under a vlan_filtering bridge, IP termination on 115 * switch ports based on 802.1Q tags is simply too brittle to 116 * be passable. So just defer to the dsa_slave_notag_xmit 117 * implementation. 118 */ 119 if (dsa_port_is_vlan_filtering(dp)) 120 return skb; 121 122 return dsa_8021q_xmit(skb, netdev, ETH_P_SJA1105, 123 ((pcp << VLAN_PRIO_SHIFT) | tx_vid)); 124 } 125 126 static void sja1105_transfer_meta(struct sk_buff *skb, 127 const struct sja1105_meta *meta) 128 { 129 struct ethhdr *hdr = eth_hdr(skb); 130 131 hdr->h_dest[3] = meta->dmac_byte_3; 132 hdr->h_dest[4] = meta->dmac_byte_4; 133 SJA1105_SKB_CB(skb)->meta_tstamp = meta->tstamp; 134 } 135 136 /* This is a simple state machine which follows the hardware mechanism of 137 * generating RX timestamps: 138 * 139 * After each timestampable skb (all traffic for which send_meta1 and 140 * send_meta0 is true, aka all MAC-filtered link-local traffic) a meta frame 141 * containing a partial timestamp is immediately generated by the switch and 142 * sent as a follow-up to the link-local frame on the CPU port. 143 * 144 * The meta frames have no unique identifier (such as sequence number) by which 145 * one may pair them to the correct timestampable frame. 146 * Instead, the switch has internal logic that ensures no frames are sent on 147 * the CPU port between a link-local timestampable frame and its corresponding 148 * meta follow-up. It also ensures strict ordering between ports (lower ports 149 * have higher priority towards the CPU port). For this reason, a per-port 150 * data structure is not needed/desirable. 151 * 152 * This function pairs the link-local frame with its partial timestamp from the 153 * meta follow-up frame. The full timestamp will be reconstructed later in a 154 * work queue. 155 */ 156 static struct sk_buff 157 *sja1105_rcv_meta_state_machine(struct sk_buff *skb, 158 struct sja1105_meta *meta, 159 bool is_link_local, 160 bool is_meta) 161 { 162 struct sja1105_port *sp; 163 struct dsa_port *dp; 164 165 dp = dsa_slave_to_port(skb->dev); 166 sp = dp->priv; 167 168 /* Step 1: A timestampable frame was received. 169 * Buffer it until we get its meta frame. 170 */ 171 if (is_link_local) { 172 if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) 173 /* Do normal processing. */ 174 return skb; 175 176 spin_lock(&sp->data->meta_lock); 177 /* Was this a link-local frame instead of the meta 178 * that we were expecting? 179 */ 180 if (sp->data->stampable_skb) { 181 dev_err_ratelimited(dp->ds->dev, 182 "Expected meta frame, is %12llx " 183 "in the DSA master multicast filter?\n", 184 SJA1105_META_DMAC); 185 kfree_skb(sp->data->stampable_skb); 186 } 187 188 /* Hold a reference to avoid dsa_switch_rcv 189 * from freeing the skb. 190 */ 191 sp->data->stampable_skb = skb_get(skb); 192 spin_unlock(&sp->data->meta_lock); 193 194 /* Tell DSA we got nothing */ 195 return NULL; 196 197 /* Step 2: The meta frame arrived. 198 * Time to take the stampable skb out of the closet, annotate it 199 * with the partial timestamp, and pretend that we received it 200 * just now (basically masquerade the buffered frame as the meta 201 * frame, which serves no further purpose). 202 */ 203 } else if (is_meta) { 204 struct sk_buff *stampable_skb; 205 206 /* Drop the meta frame if we're not in the right state 207 * to process it. 208 */ 209 if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) 210 return NULL; 211 212 spin_lock(&sp->data->meta_lock); 213 214 stampable_skb = sp->data->stampable_skb; 215 sp->data->stampable_skb = NULL; 216 217 /* Was this a meta frame instead of the link-local 218 * that we were expecting? 219 */ 220 if (!stampable_skb) { 221 dev_err_ratelimited(dp->ds->dev, 222 "Unexpected meta frame\n"); 223 spin_unlock(&sp->data->meta_lock); 224 return NULL; 225 } 226 227 if (stampable_skb->dev != skb->dev) { 228 dev_err_ratelimited(dp->ds->dev, 229 "Meta frame on wrong port\n"); 230 spin_unlock(&sp->data->meta_lock); 231 return NULL; 232 } 233 234 /* Free the meta frame and give DSA the buffered stampable_skb 235 * for further processing up the network stack. 236 */ 237 kfree_skb(skb); 238 skb = stampable_skb; 239 sja1105_transfer_meta(skb, meta); 240 241 spin_unlock(&sp->data->meta_lock); 242 } 243 244 return skb; 245 } 246 247 static struct sk_buff *sja1105_rcv(struct sk_buff *skb, 248 struct net_device *netdev, 249 struct packet_type *pt) 250 { 251 struct sja1105_meta meta = {0}; 252 int source_port, switch_id; 253 struct vlan_ethhdr *hdr; 254 u16 tpid, vid, tci; 255 bool is_link_local; 256 bool is_tagged; 257 bool is_meta; 258 259 hdr = vlan_eth_hdr(skb); 260 tpid = ntohs(hdr->h_vlan_proto); 261 is_tagged = (tpid == ETH_P_SJA1105); 262 is_link_local = sja1105_is_link_local(skb); 263 is_meta = sja1105_is_meta_frame(skb); 264 265 skb->offload_fwd_mark = 1; 266 267 if (is_tagged) { 268 /* Normal traffic path. */ 269 tci = ntohs(hdr->h_vlan_TCI); 270 vid = tci & VLAN_VID_MASK; 271 source_port = dsa_8021q_rx_source_port(vid); 272 switch_id = dsa_8021q_rx_switch_id(vid); 273 skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; 274 } else if (is_link_local) { 275 /* Management traffic path. Switch embeds the switch ID and 276 * port ID into bytes of the destination MAC, courtesy of 277 * the incl_srcpt options. 278 */ 279 source_port = hdr->h_dest[3]; 280 switch_id = hdr->h_dest[4]; 281 /* Clear the DMAC bytes that were mangled by the switch */ 282 hdr->h_dest[3] = 0; 283 hdr->h_dest[4] = 0; 284 } else if (is_meta) { 285 sja1105_meta_unpack(skb, &meta); 286 source_port = meta.source_port; 287 switch_id = meta.switch_id; 288 } else { 289 return NULL; 290 } 291 292 skb->dev = dsa_master_find_slave(netdev, switch_id, source_port); 293 if (!skb->dev) { 294 netdev_warn(netdev, "Couldn't decode source port\n"); 295 return NULL; 296 } 297 298 /* Delete/overwrite fake VLAN header, DSA expects to not find 299 * it there, see dsa_switch_rcv: skb_push(skb, ETH_HLEN). 300 */ 301 if (is_tagged) 302 skb = dsa_8021q_remove_header(skb); 303 304 return sja1105_rcv_meta_state_machine(skb, &meta, is_link_local, 305 is_meta); 306 } 307 308 static struct dsa_device_ops sja1105_netdev_ops = { 309 .name = "sja1105", 310 .proto = DSA_TAG_PROTO_SJA1105, 311 .xmit = sja1105_xmit, 312 .rcv = sja1105_rcv, 313 .filter = sja1105_filter, 314 .overhead = VLAN_HLEN, 315 }; 316 317 MODULE_LICENSE("GPL v2"); 318 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SJA1105); 319 320 module_dsa_tag_driver(sja1105_netdev_ops); 321