1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2015, The Linux Foundation. All rights reserved.
  4 */
  5
  6#include <linux/etherdevice.h>
  7
  8#include "dsa_priv.h"
  9
 10#define QCA_HDR_LEN	2
 11#define QCA_HDR_VERSION	0x2
 12
 13#define QCA_HDR_RECV_VERSION_MASK	GENMASK(15, 14)
 14#define QCA_HDR_RECV_VERSION_S		14
 15#define QCA_HDR_RECV_PRIORITY_MASK	GENMASK(13, 11)
 16#define QCA_HDR_RECV_PRIORITY_S		11
 17#define QCA_HDR_RECV_TYPE_MASK		GENMASK(10, 6)
 18#define QCA_HDR_RECV_TYPE_S		6
 19#define QCA_HDR_RECV_FRAME_IS_TAGGED	BIT(3)
 20#define QCA_HDR_RECV_SOURCE_PORT_MASK	GENMASK(2, 0)
 21
 22#define QCA_HDR_XMIT_VERSION_MASK	GENMASK(15, 14)
 23#define QCA_HDR_XMIT_VERSION_S		14
 24#define QCA_HDR_XMIT_PRIORITY_MASK	GENMASK(13, 11)
 25#define QCA_HDR_XMIT_PRIORITY_S		11
 26#define QCA_HDR_XMIT_CONTROL_MASK	GENMASK(10, 8)
 27#define QCA_HDR_XMIT_CONTROL_S		8
 28#define QCA_HDR_XMIT_FROM_CPU		BIT(7)
 29#define QCA_HDR_XMIT_DP_BIT_MASK	GENMASK(6, 0)
 30
 31static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
 32{
 33	struct dsa_port *dp = dsa_slave_to_port(dev);
 34	__be16 *phdr;
 35	u16 hdr;
 36
 37	if (skb_cow_head(skb, QCA_HDR_LEN) < 0)
 38		return NULL;
 39
 40	skb_push(skb, QCA_HDR_LEN);
 41
 42	memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
 43	phdr = (__be16 *)(skb->data + 2 * ETH_ALEN);
 44
 45	/* Set the version field, and set destination port information */
 46	hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
 47		QCA_HDR_XMIT_FROM_CPU | BIT(dp->index);
 48
 49	*phdr = htons(hdr);
 50
 51	return skb;
 52}
 53
 54static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 55				   struct packet_type *pt)
 56{
 57	u8 ver;
 58	u16  hdr;
 59	int port;
 60	__be16 *phdr;
 61
 62	if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
 63		return NULL;
 64
 65	/* The QCA header is added by the switch between src addr and Ethertype
 66	 * At this point, skb->data points to ethertype so header should be
 67	 * right before
 68	 */
 69	phdr = (__be16 *)(skb->data - 2);
 70	hdr = ntohs(*phdr);
 71
 72	/* Make sure the version is correct */
 73	ver = (hdr & QCA_HDR_RECV_VERSION_MASK) >> QCA_HDR_RECV_VERSION_S;
 74	if (unlikely(ver != QCA_HDR_VERSION))
 75		return NULL;
 76
 77	/* Remove QCA tag and recalculate checksum */
 78	skb_pull_rcsum(skb, QCA_HDR_LEN);
 79	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
 80		ETH_HLEN - QCA_HDR_LEN);
 81
 82	/* Get source port information */
 83	port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
 84
 85	skb->dev = dsa_master_find_slave(dev, 0, port);
 86	if (!skb->dev)
 87		return NULL;
 88
 89	return skb;
 90}
 91
 92static int qca_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
 93                                int *offset)
 94{
 95	*offset = QCA_HDR_LEN;
 96	*proto = ((__be16 *)skb->data)[0];
 97
 98	return 0;
 99}
100
101static const struct dsa_device_ops qca_netdev_ops = {
102	.name	= "qca",
103	.proto	= DSA_TAG_PROTO_QCA,
104	.xmit	= qca_tag_xmit,
105	.rcv	= qca_tag_rcv,
106	.flow_dissect = qca_tag_flow_dissect,
107	.overhead = QCA_HDR_LEN,
108};
109
110MODULE_LICENSE("GPL");
111MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_QCA);
112
113module_dsa_tag_driver(qca_netdev_ops);