net/dsa/tag_ocelot_8021q.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright 2020-2021 NXP Semiconductors
   3  *
   4  * An implementation of the software-defined tag_8021q.c tagger format, which
   5  * also preserves full functionality under a vlan_filtering bridge. It does
   6  * this by using the TCAM engines for:
   7  * - pushing the RX VLAN as a second, outer tag, on egress towards the CPU port
   8  * - redirecting towards the correct front port based on TX VLAN and popping
   9  *   that on egress
  10  */
  11 #include <linux/dsa/8021q.h>
  12 #include "dsa_priv.h"
  13
  14 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
  15                                    struct net_device *netdev)
  16 {
  17         struct dsa_port *dp = dsa_slave_to_port(netdev);
  18         u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
  19         u16 queue_mapping = skb_get_queue_mapping(skb);
  20         u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
  21
  22         return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
  23                               ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
  24 }
  25
  26 static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
  27                                   struct net_device *netdev,
  28                                   struct packet_type *pt)
  29 {
  30         int src_port, switch_id, qos_class;
  31         u16 vid, tci;
  32
  33         skb_push_rcsum(skb, ETH_HLEN);
  34         if (skb_vlan_tag_present(skb)) {
  35                 tci = skb_vlan_tag_get(skb);
  36                 __vlan_hwaccel_clear_tag(skb);
  37         } else {
  38                 __skb_vlan_pop(skb, &tci);
  39         }
  40         skb_pull_rcsum(skb, ETH_HLEN);
  41
  42         vid = tci & VLAN_VID_MASK;
  43         src_port = dsa_8021q_rx_source_port(vid);
  44         switch_id = dsa_8021q_rx_switch_id(vid);
  45         qos_class = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
  46
  47         skb->dev = dsa_master_find_slave(netdev, switch_id, src_port);
  48         if (!skb->dev)
  49                 return NULL;
  50
  51         skb->offload_fwd_mark = 1;
  52         skb->priority = qos_class;
  53
  54         return skb;
  55 }
  56
  57 static const struct dsa_device_ops ocelot_8021q_netdev_ops = {
  58         .name                   = "ocelot-8021q",
  59         .proto                  = DSA_TAG_PROTO_OCELOT_8021Q,
  60         .xmit                   = ocelot_xmit,
  61         .rcv                    = ocelot_rcv,
  62         .overhead               = VLAN_HLEN,
  63 };
  64
  65 MODULE_LICENSE("GPL v2");
  66 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT_8021Q);
  67
  68 module_dsa_tag_driver(ocelot_8021q_netdev_ops);