[linux-2.6-block.git] / net / dsa / tag_mtk.c

/*
 * Mediatek DSA Tag support
 * Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
 *		      Sean Wang <sean.wang@mediatek.com>
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#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;
}

const struct dsa_device_ops mtk_netdev_ops = {
	.xmit		= mtk_tag_xmit,
	.rcv		= mtk_tag_rcv,
	.flow_dissect	= mtk_tag_flow_dissect,
};
Commit	Line	Data
5cd8985a SW	1	/*
	2	* Mediatek DSA Tag support
	3	* Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
	4	* Sean Wang <sean.wang@mediatek.com>
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 and
	7	* only version 2 as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*/
	14
	15	#include <linux/etherdevice.h>
f0af3431	16	#include <linux/if_vlan.h>
ea5dd34b	17
5cd8985a SW	18	#include "dsa_priv.h"
	19
	20	#define MTK_HDR_LEN 4
f0af3431 SW	21	#define MTK_HDR_XMIT_UNTAGGED 0
f0af3431 SW	22	#define MTK_HDR_XMIT_TAGGED_TPID_8100 1
5cd8985a SW	23	#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
	24	#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
	25
	26	static struct sk_buff mtk_tag_xmit(struct sk_buff skb,
	27	struct net_device *dev)
	28	{
d945097b	29	struct dsa_port *dp = dsa_slave_to_port(dev);
5cd8985a	30	u8 *mtk_tag;
f0af3431	31	bool is_vlan_skb = true;
5cd8985a	32
f0af3431 SW	33	/* Build the special tag after the MAC Source Address. If VLAN header
	34	* is present, it's required that VLAN header and special tag is
	35	* being combined. Only in this way we can allow the switch can parse
	36	* the both special and VLAN tag at the same time and then look up VLAN
	37	* table with VID.
	38	*/
	39	if (!skb_vlan_tagged(skb)) {
	40	if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
	41	return NULL;
5cd8985a	42
f0af3431 SW	43	skb_push(skb, MTK_HDR_LEN);
	44	memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
	45	is_vlan_skb = false;
	46	}
5cd8985a	47
5cd8985a	48	mtk_tag = skb->data + 2 * ETH_ALEN;
f0af3431 SW	49
	50	/* Mark tag attribute on special tag insertion to notify hardware
	51	* whether that's a combined special tag with 802.1Q header.
	52	*/
	53	mtk_tag[0] = is_vlan_skb ? MTK_HDR_XMIT_TAGGED_TPID_8100 :
	54	MTK_HDR_XMIT_UNTAGGED;
d945097b	55	mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
f0af3431 SW	56
	57	/* Tag control information is kept for 802.1Q */
	58	if (!is_vlan_skb) {
	59	mtk_tag[2] = 0;
	60	mtk_tag[3] = 0;
	61	}
5cd8985a SW	62
5cd8985a SW	63	return skb;
5cd8985a SW	64	}
5cd8985a SW	65
a86d8bec	66	static struct sk_buff mtk_tag_rcv(struct sk_buff skb, struct net_device *dev,
89e49506	67	struct packet_type *pt)
5cd8985a	68	{
5cd8985a SW	69	int port;
	70	__be16 *phdr, hdr;
	71
5cd8985a	72	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
54709795	73	return NULL;
5cd8985a SW	74
	75	/* The MTK header is added by the switch between src addr
	76	* and ethertype at this point, skb->data points to 2 bytes
	77	* after src addr so header should be 2 bytes right before.
	78	*/
	79	phdr = (__be16 *)(skb->data - 2);
	80	hdr = ntohs(*phdr);
	81
	82	/* Remove MTK tag and recalculate checksum. */
	83	skb_pull_rcsum(skb, MTK_HDR_LEN);
	84
	85	memmove(skb->data - ETH_HLEN,
	86	skb->data - ETH_HLEN - MTK_HDR_LEN,
	87	2 * ETH_ALEN);
	88
5cd8985a SW	89	/* Get source port information */
5cd8985a SW	90	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
5cd8985a	91
2231c43b	92	skb->dev = dsa_master_find_slave(dev, 0, port);
3775b1b7 VD	93	if (!skb->dev)
3775b1b7 VD	94	return NULL;
5cd8985a	95
a86d8bec	96	return skb;
5cd8985a SW	97	}
5cd8985a SW	98
2dd592b2 JC	99	static int mtk_tag_flow_dissect(const struct sk_buff skb, __be16 proto,
	100	int *offset)
	101	{
	102	*offset = 4;
	103	proto = ((__be16 )skb->data)[1];
	104
	105	return 0;
	106	}
	107
5cd8985a	108	const struct dsa_device_ops mtk_netdev_ops = {
2dd592b2 JC	109	.xmit = mtk_tag_xmit,
	110	.rcv = mtk_tag_rcv,
	111	.flow_dissect = mtk_tag_flow_dissect,
5cd8985a	112	};