linux/net/dsa/tag_rtl4_a.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Handler for Realtek 4 byte DSA switch tags
 * Currently only supports protocol "A" found in RTL8366RB
 * Copyright (c) 2020 Linus Walleij <[email protected]>
 *
 * This "proprietary tag" header looks like so:
 *
 * -------------------------------------------------
 * | MAC DA | MAC SA | 0x8899 | 2 bytes tag | Type |
 * -------------------------------------------------
 *
 * The 2 bytes tag form a 16 bit big endian word. The exact
 * meaning has been guessed from packet dumps from ingress
 * frames.
 */

#include <linux/etherdevice.h>
#include <linux/bits.h>

#include "tag.h"

#define RTL4_A_NAME …

#define RTL4_A_HDR_LEN …
#define RTL4_A_PROTOCOL_SHIFT …
/*
 * 0x1 = Realtek Remote Control protocol (RRCP)
 * 0x2/0x3 seems to be used for loopback testing
 * 0x9 = RTL8306 DSA protocol
 * 0xa = RTL8366RB DSA protocol
 */
#define RTL4_A_PROTOCOL_RTL8366RB …

static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
				      struct net_device *dev)
{ … }

static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb,
				     struct net_device *dev)
{ … }

static const struct dsa_device_ops rtl4a_netdev_ops = …;
module_dsa_tag_driver(rtl4a_netdev_ops);

MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;
MODULE_ALIAS_DSA_TAG_DRIVER(…);