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 <soc/mscc/ocelot.h>
  13 #include <soc/mscc/ocelot_ptp.h>
  14 #include "dsa_priv.h"
  15
  16 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
  17                                    struct net_device *netdev)
  18 {
  19         struct dsa_port *dp = dsa_slave_to_port(netdev);
  20         u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
  21         u16 queue_mapping = skb_get_queue_mapping(skb);
  22         u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
  23         struct ocelot *ocelot = dp->ds->priv;
  24         int port = dp->index;
  25         u32 rew_op = 0;
  26
  27         rew_op = ocelot_ptp_rew_op(skb);
  28         if (rew_op) {
  29                 if (!ocelot_can_inject(ocelot, 0))
  30                         return NULL;
  31
  32                 ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
  33                 return NULL;
  34         }
  35
  36         return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
  37                               ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
  38 }
  39
  40 static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
  41                                   struct net_device *netdev,
  42                                   struct packet_type *pt)
  43 {
  44         int src_port, switch_id, qos_class;
  45         u16 vid, tci;
  46
  47         skb_push_rcsum(skb, ETH_HLEN);
  48         if (skb_vlan_tag_present(skb)) {
  49                 tci = skb_vlan_tag_get(skb);
  50                 __vlan_hwaccel_clear_tag(skb);
  51         } else {
  52                 __skb_vlan_pop(skb, &tci);
  53         }
  54         skb_pull_rcsum(skb, ETH_HLEN);
  55
  56         vid = tci & VLAN_VID_MASK;
  57         src_port = dsa_8021q_rx_source_port(vid);
  58         switch_id = dsa_8021q_rx_switch_id(vid);
  59         qos_class = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
  60
  61         skb->dev = dsa_master_find_slave(netdev, switch_id, src_port);
  62         if (!skb->dev)
  63                 return NULL;
  64
  65         skb->offload_fwd_mark = 1;
  66         skb->priority = qos_class;
  67
  68         return skb;
  69 }
  70
  71 static const struct dsa_device_ops ocelot_8021q_netdev_ops = {
  72         .name                   = "ocelot-8021q",
  73         .proto                  = DSA_TAG_PROTO_OCELOT_8021Q,
  74         .xmit                   = ocelot_xmit,
  75         .rcv                    = ocelot_rcv,
  76         .overhead               = VLAN_HLEN,
  77         .promisc_on_master      = true,
  78 };
  79
  80 MODULE_LICENSE("GPL v2");
  81 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT_8021Q);
  82
  83 module_dsa_tag_driver(ocelot_8021q_netdev_ops);