net/dsa/tag_gswip.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Intel / Lantiq GSWIP V2.0 PMAC tag support
   4  *
   5  * Copyright (C) 2017 - 2018 Hauke Mehrtens <hauke@hauke-m.de>
   6  */
   7
   8 #include <linux/bitops.h>
   9 #include <linux/etherdevice.h>
  10 #include <linux/skbuff.h>
  11 #include <net/dsa.h>
  12
  13 #include "tag.h"
  14
  15 #define GSWIP_NAME                      "gswip"
  16
  17 #define GSWIP_TX_HEADER_LEN             4
  18
  19 /* special tag in TX path header */
  20 /* Byte 0 */
  21 #define GSWIP_TX_SLPID_SHIFT            0       /* source port ID */
  22 #define  GSWIP_TX_SLPID_CPU             2
  23 #define  GSWIP_TX_SLPID_APP1            3
  24 #define  GSWIP_TX_SLPID_APP2            4
  25 #define  GSWIP_TX_SLPID_APP3            5
  26 #define  GSWIP_TX_SLPID_APP4            6
  27 #define  GSWIP_TX_SLPID_APP5            7
  28
  29 /* Byte 1 */
  30 #define GSWIP_TX_CRCGEN_DIS             BIT(7)
  31 #define GSWIP_TX_DPID_SHIFT             0       /* destination group ID */
  32 #define  GSWIP_TX_DPID_ELAN             0
  33 #define  GSWIP_TX_DPID_EWAN             1
  34 #define  GSWIP_TX_DPID_CPU              2
  35 #define  GSWIP_TX_DPID_APP1             3
  36 #define  GSWIP_TX_DPID_APP2             4
  37 #define  GSWIP_TX_DPID_APP3             5
  38 #define  GSWIP_TX_DPID_APP4             6
  39 #define  GSWIP_TX_DPID_APP5             7
  40
  41 /* Byte 2 */
  42 #define GSWIP_TX_PORT_MAP_EN            BIT(7)
  43 #define GSWIP_TX_PORT_MAP_SEL           BIT(6)
  44 #define GSWIP_TX_LRN_DIS                BIT(5)
  45 #define GSWIP_TX_CLASS_EN               BIT(4)
  46 #define GSWIP_TX_CLASS_SHIFT            0
  47 #define GSWIP_TX_CLASS_MASK             GENMASK(3, 0)
  48
  49 /* Byte 3 */
  50 #define GSWIP_TX_DPID_EN                BIT(0)
  51 #define GSWIP_TX_PORT_MAP_SHIFT         1
  52 #define GSWIP_TX_PORT_MAP_MASK          GENMASK(6, 1)
  53
  54 #define GSWIP_RX_HEADER_LEN     8
  55
  56 /* special tag in RX path header */
  57 /* Byte 7 */
  58 #define GSWIP_RX_SPPID_SHIFT            4
  59 #define GSWIP_RX_SPPID_MASK             GENMASK(6, 4)
  60
  61 static struct sk_buff *gswip_tag_xmit(struct sk_buff *skb,
  62                                       struct net_device *dev)
  63 {
  64         struct dsa_port *dp = dsa_user_to_port(dev);
  65         u8 *gswip_tag;
  66
  67         skb_push(skb, GSWIP_TX_HEADER_LEN);
  68
  69         gswip_tag = skb->data;
  70         gswip_tag[0] = GSWIP_TX_SLPID_CPU;
  71         gswip_tag[1] = GSWIP_TX_DPID_ELAN;
  72         gswip_tag[2] = GSWIP_TX_PORT_MAP_EN | GSWIP_TX_PORT_MAP_SEL;
  73         gswip_tag[3] = BIT(dp->index + GSWIP_TX_PORT_MAP_SHIFT) & GSWIP_TX_PORT_MAP_MASK;
  74         gswip_tag[3] |= GSWIP_TX_DPID_EN;
  75
  76         return skb;
  77 }
  78
  79 static struct sk_buff *gswip_tag_rcv(struct sk_buff *skb,
  80                                      struct net_device *dev)
  81 {
  82         int port;
  83         u8 *gswip_tag;
  84
  85         if (unlikely(!pskb_may_pull(skb, GSWIP_RX_HEADER_LEN)))
  86                 return NULL;
  87
  88         gswip_tag = skb->data - ETH_HLEN;
  89
  90         /* Get source port information */
  91         port = (gswip_tag[7] & GSWIP_RX_SPPID_MASK) >> GSWIP_RX_SPPID_SHIFT;
  92         skb->dev = dsa_conduit_find_user(dev, 0, port);
  93         if (!skb->dev)
  94                 return NULL;
  95
  96         /* remove GSWIP tag */
  97         skb_pull_rcsum(skb, GSWIP_RX_HEADER_LEN);
  98
  99         return skb;
 100 }
 101
 102 static const struct dsa_device_ops gswip_netdev_ops = {
 103         .name = GSWIP_NAME,
 104         .proto  = DSA_TAG_PROTO_GSWIP,
 105         .xmit = gswip_tag_xmit,
 106         .rcv = gswip_tag_rcv,
 107         .needed_headroom = GSWIP_RX_HEADER_LEN,
 108 };
 109
 110 MODULE_DESCRIPTION("DSA tag driver for Lantiq / Intel GSWIP switches");
 111 MODULE_LICENSE("GPL");
 112 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_GSWIP, GSWIP_NAME);
 113
 114 module_dsa_tag_driver(gswip_netdev_ops);