LXR linux/net/dsa/tag

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2019 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
   4 */
   5
   6
   7#include <linux/bitfield.h>
   8#include <linux/etherdevice.h>
   9
  10#include "dsa_priv.h"
  11
  12#define AR9331_HDR_LEN                  2
  13#define AR9331_HDR_VERSION              1
  14
  15#define AR9331_HDR_VERSION_MASK         GENMASK(15, 14)
  16#define AR9331_HDR_PRIORITY_MASK        GENMASK(13, 12)
  17#define AR9331_HDR_TYPE_MASK            GENMASK(10, 8)
  18#define AR9331_HDR_BROADCAST            BIT(7)
  19#define AR9331_HDR_FROM_CPU             BIT(6)
  20/* AR9331_HDR_RESERVED - not used or may be version field.
  21 * According to the AR8216 doc it should 0b10. On AR9331 it is 0b11 on RX path
  22 * and should be set to 0b11 to make it work.
  23 */
  24#define AR9331_HDR_RESERVED_MASK        GENMASK(5, 4)
  25#define AR9331_HDR_PORT_NUM_MASK        GENMASK(3, 0)
  26
  27static struct sk_buff *ar9331_tag_xmit(struct sk_buff *skb,
  28                                       struct net_device *dev)
  29{
  30        struct dsa_port *dp = dsa_slave_to_port(dev);
  31        __le16 *phdr;
  32        u16 hdr;
  33
  34        phdr = skb_push(skb, AR9331_HDR_LEN);
  35
  36        hdr = FIELD_PREP(AR9331_HDR_VERSION_MASK, AR9331_HDR_VERSION);
  37        hdr |= AR9331_HDR_FROM_CPU | dp->index;
  38        /* 0b10 for AR8216 and 0b11 for AR9331 */
  39        hdr |= AR9331_HDR_RESERVED_MASK;
  40
  41        phdr[0] = cpu_to_le16(hdr);
  42
  43        return skb;
  44}
  45
  46static struct sk_buff *ar9331_tag_rcv(struct sk_buff *skb,
  47                                      struct net_device *ndev)
  48{
  49        u8 ver, port;
  50        u16 hdr;
  51
  52        if (unlikely(!pskb_may_pull(skb, AR9331_HDR_LEN)))
  53                return NULL;
  54
  55        hdr = le16_to_cpu(*(__le16 *)skb_mac_header(skb));
  56
  57        ver = FIELD_GET(AR9331_HDR_VERSION_MASK, hdr);
  58        if (unlikely(ver != AR9331_HDR_VERSION)) {
  59                netdev_warn_once(ndev, "%s:%i wrong header version 0x%2x\n",
  60                                 __func__, __LINE__, hdr);
  61                return NULL;
  62        }
  63
  64        if (unlikely(hdr & AR9331_HDR_FROM_CPU)) {
  65                netdev_warn_once(ndev, "%s:%i packet should not be from cpu 0x%2x\n",
  66                                 __func__, __LINE__, hdr);
  67                return NULL;
  68        }
  69
  70        skb_pull_rcsum(skb, AR9331_HDR_LEN);
  71
  72        /* Get source port information */
  73        port = FIELD_GET(AR9331_HDR_PORT_NUM_MASK, hdr);
  74
  75        skb->dev = dsa_master_find_slave(ndev, 0, port);
  76        if (!skb->dev)
  77                return NULL;
  78
  79        return skb;
  80}
  81
  82static const struct dsa_device_ops ar9331_netdev_ops = {
  83        .name   = "ar9331",
  84        .proto  = DSA_TAG_PROTO_AR9331,
  85        .xmit   = ar9331_tag_xmit,
  86        .rcv    = ar9331_tag_rcv,
  87        .needed_headroom = AR9331_HDR_LEN,
  88};
  89
  90MODULE_LICENSE("GPL v2");
  91MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_AR9331);
  92module_dsa_tag_driver(ar9331_netdev_ops);
  93