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	skb_push(skb, QCA_HDR_LEN);
 38
 39	memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
 40	phdr = (__be16 *)(skb->data + 2 * ETH_ALEN);
 41
 42	/* Set the version field, and set destination port information */
 43	hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
 44		QCA_HDR_XMIT_FROM_CPU | BIT(dp->index);
 45
 46	*phdr = htons(hdr);
 47
 48	return skb;
 49}
 50
 51static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 52				   struct packet_type *pt)
 53{
 54	u8 ver;
 55	u16  hdr;
 56	int port;
 57	__be16 *phdr;
 58
 59	if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
 60		return NULL;
 61
 62	/* The QCA header is added by the switch between src addr and Ethertype
 63	 * At this point, skb->data points to ethertype so header should be
 64	 * right before
 65	 */
 66	phdr = (__be16 *)(skb->data - 2);
 67	hdr = ntohs(*phdr);
 68
 69	/* Make sure the version is correct */
 70	ver = (hdr & QCA_HDR_RECV_VERSION_MASK) >> QCA_HDR_RECV_VERSION_S;
 71	if (unlikely(ver != QCA_HDR_VERSION))
 72		return NULL;
 73
 74	/* Remove QCA tag and recalculate checksum */
 75	skb_pull_rcsum(skb, QCA_HDR_LEN);
 76	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
 77		ETH_HLEN - QCA_HDR_LEN);
 78
 79	/* Get source port information */
 80	port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
 81
 82	skb->dev = dsa_master_find_slave(dev, 0, port);
 83	if (!skb->dev)
 84		return NULL;
 85
 86	return skb;
 87}
 88
 89static const struct dsa_device_ops qca_netdev_ops = {
 90	.name	= "qca",
 91	.proto	= DSA_TAG_PROTO_QCA,
 92	.xmit	= qca_tag_xmit,
 93	.rcv	= qca_tag_rcv,
 94	.needed_headroom = QCA_HDR_LEN,
 95};
 96
 97MODULE_LICENSE("GPL");
 98MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_QCA);
 99
100module_dsa_tag_driver(qca_netdev_ops);