[linux-block.git] / net / dsa / tag_mtk.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Mediatek DSA Tag support
 * Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
 *		      Sean Wang <sean.wang@mediatek.com>
 */

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

#include "dsa_priv.h"

#define MTK_HDR_LEN		4
#define MTK_HDR_XMIT_UNTAGGED		0
#define MTK_HDR_XMIT_TAGGED_TPID_8100	1
#define MTK_HDR_RECV_SOURCE_PORT_MASK	GENMASK(2, 0)
#define MTK_HDR_XMIT_DP_BIT_MASK	GENMASK(5, 0)

static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
				    struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	u8 *mtk_tag;
	bool is_vlan_skb = true;

	/* Build the special tag after the MAC Source Address. If VLAN header
	 * is present, it's required that VLAN header and special tag is
	 * being combined. Only in this way we can allow the switch can parse
	 * the both special and VLAN tag at the same time and then look up VLAN
	 * table with VID.
	 */
	if (!skb_vlan_tagged(skb)) {
		if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
			return NULL;

		skb_push(skb, MTK_HDR_LEN);
		memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
		is_vlan_skb = false;
	}

	mtk_tag = skb->data + 2 * ETH_ALEN;

	/* Mark tag attribute on special tag insertion to notify hardware
	 * whether that's a combined special tag with 802.1Q header.
	 */
	mtk_tag[0] = is_vlan_skb ? MTK_HDR_XMIT_TAGGED_TPID_8100 :
		     MTK_HDR_XMIT_UNTAGGED;
	mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;

	/* Tag control information is kept for 802.1Q */
	if (!is_vlan_skb) {
		mtk_tag[2] = 0;
		mtk_tag[3] = 0;
	}

	return skb;
}

static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
				   struct packet_type *pt)
{
	int port;
	__be16 *phdr, hdr;

	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
		return NULL;

	/* The MTK header is added by the switch between src addr
	 * and ethertype at this point, skb->data points to 2 bytes
	 * after src addr so header should be 2 bytes right before.
	 */
	phdr = (__be16 *)(skb->data - 2);
	hdr = ntohs(*phdr);

	/* Remove MTK tag and recalculate checksum. */
	skb_pull_rcsum(skb, MTK_HDR_LEN);

	memmove(skb->data - ETH_HLEN,
		skb->data - ETH_HLEN - MTK_HDR_LEN,
		2 * ETH_ALEN);

	/* Get source port information */
	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);

	skb->dev = dsa_master_find_slave(dev, 0, port);
	if (!skb->dev)
		return NULL;

	return skb;
}

static int mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
				int *offset)
{
	*offset = 4;
	*proto = ((__be16 *)skb->data)[1];

	return 0;
}

static const struct dsa_device_ops mtk_netdev_ops = {
	.name		= "mtk",
	.proto		= DSA_TAG_PROTO_MTK,
	.xmit		= mtk_tag_xmit,
	.rcv		= mtk_tag_rcv,
	.flow_dissect	= mtk_tag_flow_dissect,
	.overhead	= MTK_HDR_LEN,
};

MODULE_LICENSE("GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK);

module_dsa_tag_driver(mtk_netdev_ops);
Commit	Line	Data
dfedd3b6	1	// SPDX-License-Identifier: GPL-2.0
5cd8985a SW	2	/*
	3	* Mediatek DSA Tag support
	4	* Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
	5	* Sean Wang <sean.wang@mediatek.com>
5cd8985a SW	6	*/
	7
	8	#include <linux/etherdevice.h>
f0af3431	9	#include <linux/if_vlan.h>
ea5dd34b	10
5cd8985a SW	11	#include "dsa_priv.h"
	12
	13	#define MTK_HDR_LEN 4
f0af3431 SW	14	#define MTK_HDR_XMIT_UNTAGGED 0
f0af3431 SW	15	#define MTK_HDR_XMIT_TAGGED_TPID_8100 1
5cd8985a SW	16	#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
	17	#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
	18
	19	static struct sk_buff mtk_tag_xmit(struct sk_buff skb,
	20	struct net_device *dev)
	21	{
d945097b	22	struct dsa_port *dp = dsa_slave_to_port(dev);
5cd8985a	23	u8 *mtk_tag;
f0af3431	24	bool is_vlan_skb = true;
5cd8985a	25
f0af3431 SW	26	/* Build the special tag after the MAC Source Address. If VLAN header
	27	* is present, it's required that VLAN header and special tag is
	28	* being combined. Only in this way we can allow the switch can parse
	29	* the both special and VLAN tag at the same time and then look up VLAN
	30	* table with VID.
	31	*/
	32	if (!skb_vlan_tagged(skb)) {
	33	if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
	34	return NULL;
5cd8985a	35
f0af3431 SW	36	skb_push(skb, MTK_HDR_LEN);
	37	memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
	38	is_vlan_skb = false;
	39	}
5cd8985a	40
5cd8985a	41	mtk_tag = skb->data + 2 * ETH_ALEN;
f0af3431 SW	42
	43	/* Mark tag attribute on special tag insertion to notify hardware
	44	* whether that's a combined special tag with 802.1Q header.
	45	*/
	46	mtk_tag[0] = is_vlan_skb ? MTK_HDR_XMIT_TAGGED_TPID_8100 :
	47	MTK_HDR_XMIT_UNTAGGED;
d945097b	48	mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
f0af3431 SW	49
	50	/* Tag control information is kept for 802.1Q */
	51	if (!is_vlan_skb) {
	52	mtk_tag[2] = 0;
	53	mtk_tag[3] = 0;
	54	}
5cd8985a SW	55
5cd8985a SW	56	return skb;
5cd8985a SW	57	}
5cd8985a SW	58
a86d8bec	59	static struct sk_buff mtk_tag_rcv(struct sk_buff skb, struct net_device *dev,
89e49506	60	struct packet_type *pt)
5cd8985a	61	{
5cd8985a SW	62	int port;
	63	__be16 *phdr, hdr;
	64
5cd8985a	65	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
54709795	66	return NULL;
5cd8985a SW	67
	68	/* The MTK header is added by the switch between src addr
	69	* and ethertype at this point, skb->data points to 2 bytes
	70	* after src addr so header should be 2 bytes right before.
	71	*/
	72	phdr = (__be16 *)(skb->data - 2);
	73	hdr = ntohs(*phdr);
	74
	75	/* Remove MTK tag and recalculate checksum. */
	76	skb_pull_rcsum(skb, MTK_HDR_LEN);
	77
	78	memmove(skb->data - ETH_HLEN,
	79	skb->data - ETH_HLEN - MTK_HDR_LEN,
	80	2 * ETH_ALEN);
	81
5cd8985a SW	82	/* Get source port information */
5cd8985a SW	83	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
5cd8985a	84
2231c43b	85	skb->dev = dsa_master_find_slave(dev, 0, port);
3775b1b7 VD	86	if (!skb->dev)
3775b1b7 VD	87	return NULL;
5cd8985a	88
a86d8bec	89	return skb;
5cd8985a SW	90	}
5cd8985a SW	91
2dd592b2 JC	92	static int mtk_tag_flow_dissect(const struct sk_buff skb, __be16 proto,
	93	int *offset)
	94	{
	95	*offset = 4;
	96	proto = ((__be16 )skb->data)[1];
	97
	98	return 0;
	99	}
	100
f81a43e8	101	static const struct dsa_device_ops mtk_netdev_ops = {
875138f8	102	.name = "mtk",
056eed2f	103	.proto = DSA_TAG_PROTO_MTK,
2dd592b2 JC	104	.xmit = mtk_tag_xmit,
	105	.rcv = mtk_tag_rcv,
	106	.flow_dissect = mtk_tag_flow_dissect,
a5dd3087	107	.overhead = MTK_HDR_LEN,
5cd8985a	108	};
0b42f033	109
f18bba50	110	MODULE_LICENSE("GPL");
0b42f033	111	MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK);
d3b8c049 AL	112
d3b8c049 AL	113	module_dsa_tag_driver(mtk_netdev_ops);