// SPDX-License-Identifier: GPL-2.0+
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/*
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* Broadcom tag support
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*
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* Copyright (C) 2014 Broadcom Corporation
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*/
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include "dsa_priv.h"
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/* This tag length is 4 bytes, older ones were 6 bytes, we do not
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* handle them
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*/
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#define BRCM_TAG_LEN 4
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/* Tag is constructed and desconstructed using byte by byte access
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* because the tag is placed after the MAC Source Address, which does
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* not make it 4-bytes aligned, so this might cause unaligned accesses
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* on most systems where this is used.
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*/
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/* Ingress and egress opcodes */
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#define BRCM_OPCODE_SHIFT 5
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#define BRCM_OPCODE_MASK 0x7
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/* Ingress fields */
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/* 1st byte in the tag */
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#define BRCM_IG_TC_SHIFT 2
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#define BRCM_IG_TC_MASK 0x7
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/* 2nd byte in the tag */
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#define BRCM_IG_TE_MASK 0x3
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#define BRCM_IG_TS_SHIFT 7
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/* 3rd byte in the tag */
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#define BRCM_IG_DSTMAP2_MASK 1
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#define BRCM_IG_DSTMAP1_MASK 0xff
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/* Egress fields */
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/* 2nd byte in the tag */
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#define BRCM_EG_CID_MASK 0xff
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/* 3rd byte in the tag */
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#define BRCM_EG_RC_MASK 0xff
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#define BRCM_EG_RC_RSVD (3 << 6)
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#define BRCM_EG_RC_EXCEPTION (1 << 5)
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#define BRCM_EG_RC_PROT_SNOOP (1 << 4)
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#define BRCM_EG_RC_PROT_TERM (1 << 3)
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#define BRCM_EG_RC_SWITCH (1 << 2)
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#define BRCM_EG_RC_MAC_LEARN (1 << 1)
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#define BRCM_EG_RC_MIRROR (1 << 0)
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#define BRCM_EG_TC_SHIFT 5
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#define BRCM_EG_TC_MASK 0x7
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#define BRCM_EG_PID_MASK 0x1f
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
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IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
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static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
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struct net_device *dev,
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unsigned int offset)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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u16 queue = skb_get_queue_mapping(skb);
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u8 *brcm_tag;
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/* The Ethernet switch we are interfaced with needs packets to be at
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* least 64 bytes (including FCS) otherwise they will be discarded when
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* they enter the switch port logic. When Broadcom tags are enabled, we
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* need to make sure that packets are at least 68 bytes
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* (including FCS and tag) because the length verification is done after
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* the Broadcom tag is stripped off the ingress packet.
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*
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* Let dsa_slave_xmit() free the SKB
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*/
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if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
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return NULL;
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skb_push(skb, BRCM_TAG_LEN);
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if (offset)
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memmove(skb->data, skb->data + BRCM_TAG_LEN, offset);
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brcm_tag = skb->data + offset;
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/* Set the ingress opcode, traffic class, tag enforcment is
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* deprecated
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*/
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brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
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((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
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brcm_tag[1] = 0;
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brcm_tag[2] = 0;
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if (dp->index == 8)
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brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
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brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
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/* Now tell the master network device about the desired output queue
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* as well
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*/
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skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
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return skb;
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}
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/* Frames with this tag have one of these two layouts:
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* -----------------------------------
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* | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
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* -----------------------------------
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* -----------------------------------
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* | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
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* -----------------------------------
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* In both cases, at receive time, skb->data points 2 bytes before the actual
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* Ethernet type field and we have an offset of 4bytes between where skb->data
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* and where the payload starts. So the same low-level receive function can be
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* used.
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*/
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static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt,
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unsigned int offset)
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{
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int source_port;
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u8 *brcm_tag;
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if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
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return NULL;
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brcm_tag = skb->data - offset;
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/* The opcode should never be different than 0b000 */
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if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
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return NULL;
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/* We should never see a reserved reason code without knowing how to
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* handle it
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*/
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if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
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return NULL;
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/* Locate which port this is coming from */
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source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
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skb->dev = dsa_master_find_slave(dev, 0, source_port);
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if (!skb->dev)
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return NULL;
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/* Remove Broadcom tag and update checksum */
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skb_pull_rcsum(skb, BRCM_TAG_LEN);
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skb->offload_fwd_mark = 1;
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return skb;
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}
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
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static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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/* Build the tag after the MAC Source Address */
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return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
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}
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static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt)
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{
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struct sk_buff *nskb;
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/* skb->data points to the EtherType, the tag is right before it */
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nskb = brcm_tag_rcv_ll(skb, dev, pt, 2);
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if (!nskb)
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return nskb;
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/* Move the Ethernet DA and SA */
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memmove(nskb->data - ETH_HLEN,
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nskb->data - ETH_HLEN - BRCM_TAG_LEN,
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2 * ETH_ALEN);
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return nskb;
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}
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static const struct dsa_device_ops brcm_netdev_ops = {
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.name = "brcm",
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.proto = DSA_TAG_PROTO_BRCM,
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.xmit = brcm_tag_xmit,
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.rcv = brcm_tag_rcv,
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.overhead = BRCM_TAG_LEN,
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};
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DSA_TAG_DRIVER(brcm_netdev_ops);
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
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static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
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struct net_device *dev)
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{
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/* tag is prepended to the packet */
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return brcm_tag_xmit_ll(skb, dev, 0);
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}
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static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt)
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{
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/* tag is prepended to the packet */
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return brcm_tag_rcv_ll(skb, dev, pt, ETH_HLEN);
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}
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static const struct dsa_device_ops brcm_prepend_netdev_ops = {
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.name = "brcm-prepend",
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.proto = DSA_TAG_PROTO_BRCM_PREPEND,
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.xmit = brcm_tag_xmit_prepend,
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.rcv = brcm_tag_rcv_prepend,
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.overhead = BRCM_TAG_LEN,
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};
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DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND);
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#endif
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static struct dsa_tag_driver *dsa_tag_driver_array[] = {
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
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&DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
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&DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
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#endif
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};
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module_dsa_tag_drivers(dsa_tag_driver_array);
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MODULE_LICENSE("GPL");
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