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

/*
 * Broadcom tag support
 *
 * Copyright (C) 2014 Broadcom Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/slab.h>
#include "dsa_priv.h"

/* This tag length is 4 bytes, older ones were 6 bytes, we do not
 * handle them
 */
#define BRCM_TAG_LEN	4

/* Tag is constructed and desconstructed using byte by byte access
 * because the tag is placed after the MAC Source Address, which does
 * not make it 4-bytes aligned, so this might cause unaligned accesses
 * on most systems where this is used.
 */

/* Ingress and egress opcodes */
#define BRCM_OPCODE_SHIFT	5
#define BRCM_OPCODE_MASK	0x7

/* Ingress fields */
/* 1st byte in the tag */
#define BRCM_IG_TC_SHIFT	2
#define BRCM_IG_TC_MASK		0x7
/* 2nd byte in the tag */
#define BRCM_IG_TE_MASK		0x3
#define BRCM_IG_TS_SHIFT	7
/* 3rd byte in the tag */
#define BRCM_IG_DSTMAP2_MASK	1
#define BRCM_IG_DSTMAP1_MASK	0xff

/* Egress fields */

/* 2nd byte in the tag */
#define BRCM_EG_CID_MASK	0xff

/* 3rd byte in the tag */
#define BRCM_EG_RC_MASK		0xff
#define  BRCM_EG_RC_RSVD	(3 << 6)
#define  BRCM_EG_RC_EXCEPTION	(1 << 5)
#define  BRCM_EG_RC_PROT_SNOOP	(1 << 4)
#define  BRCM_EG_RC_PROT_TERM	(1 << 3)
#define  BRCM_EG_RC_SWITCH	(1 << 2)
#define  BRCM_EG_RC_MAC_LEARN	(1 << 1)
#define  BRCM_EG_RC_MIRROR	(1 << 0)
#define BRCM_EG_TC_SHIFT	5
#define BRCM_EG_TC_MASK		0x7
#define BRCM_EG_PID_MASK	0x1f

static netdev_tx_t brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct dsa_slave_priv *p = netdev_priv(dev);
	u8 *brcm_tag;

	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;

	if (skb_cow_head(skb, BRCM_TAG_LEN) < 0)
		goto out_free;

	skb_push(skb, BRCM_TAG_LEN);

	memmove(skb->data, skb->data + BRCM_TAG_LEN, 2 * ETH_ALEN);

	/* Build the tag after the MAC Source Address */
	brcm_tag = skb->data + 2 * ETH_ALEN;

	/* Set the ingress opcode, traffic class, tag enforcment is
	 * deprecated
	 */
	brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
			((skb->priority << BRCM_IG_TC_SHIFT) & BRCM_IG_TC_MASK);
	brcm_tag[1] = 0;
	brcm_tag[2] = 0;
	if (p->port == 8)
		brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
	brcm_tag[3] = (1 << p->port) & BRCM_IG_DSTMAP1_MASK;

	/* Queue the SKB for transmission on the parent interface, but
	 * do not modify its EtherType
	 */
	skb->dev = p->parent->dst->master_netdev;
	dev_queue_xmit(skb);

	return NETDEV_TX_OK;

out_free:
	kfree_skb(skb);
	return NETDEV_TX_OK;
}

static int brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev,
			struct packet_type *pt, struct net_device *orig_dev)
{
	struct dsa_switch_tree *dst = dev->dsa_ptr;
	struct dsa_switch *ds;
	int source_port;
	u8 *brcm_tag;

	if (unlikely(dst == NULL))
		goto out_drop;

	ds = dst->ds[0];

	skb = skb_unshare(skb, GFP_ATOMIC);
	if (skb == NULL)
		goto out;

	if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
		goto out_drop;

	/* skb->data points to the EtherType, the tag is right before it */
	brcm_tag = skb->data - 2;

	/* The opcode should never be different than 0b000 */
	if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
		goto out_drop;

	/* We should never see a reserved reason code without knowing how to
	 * handle it
	 */
	WARN_ON(brcm_tag[2] & BRCM_EG_RC_RSVD);

	/* Locate which port this is coming from */
	source_port = brcm_tag[3] & BRCM_EG_PID_MASK;

	/* Validate port against switch setup, either the port is totally */
	if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
		goto out_drop;

	/* Remove Broadcom tag and update checksum */
	skb_pull_rcsum(skb, BRCM_TAG_LEN);

	/* Move the Ethernet DA and SA */
	memmove(skb->data - ETH_HLEN,
		skb->data - ETH_HLEN - BRCM_TAG_LEN,
		2 * ETH_ALEN);

	skb_push(skb, ETH_HLEN);
	skb->pkt_type = PACKET_HOST;
	skb->dev = ds->ports[source_port];
	skb->protocol = eth_type_trans(skb, skb->dev);

	skb->dev->stats.rx_packets++;
	skb->dev->stats.rx_bytes += skb->len;

	netif_receive_skb(skb);

	return 0;

out_drop:
	kfree_skb(skb);
out:
	return 0;
}

const struct dsa_device_ops brcm_netdev_ops = {
	.xmit	= brcm_tag_xmit,
	.rcv	= brcm_tag_rcv,
};
Commit	Line	Data
5037d532 FF	1	/*
	2	* Broadcom tag support
	3	*
	4	* Copyright (C) 2014 Broadcom Corporation
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*/
	11
	12	#include <linux/etherdevice.h>
	13	#include <linux/list.h>
5037d532 FF	14	#include <linux/slab.h>
	15	#include "dsa_priv.h"
	16
	17	/* This tag length is 4 bytes, older ones were 6 bytes, we do not
	18	* handle them
	19	*/
	20	#define BRCM_TAG_LEN 4
	21
	22	/* Tag is constructed and desconstructed using byte by byte access
	23	* because the tag is placed after the MAC Source Address, which does
	24	* not make it 4-bytes aligned, so this might cause unaligned accesses
	25	* on most systems where this is used.
	26	*/
	27
	28	/* Ingress and egress opcodes */
	29	#define BRCM_OPCODE_SHIFT 5
	30	#define BRCM_OPCODE_MASK 0x7
	31
	32	/* Ingress fields */
	33	/* 1st byte in the tag */
	34	#define BRCM_IG_TC_SHIFT 2
	35	#define BRCM_IG_TC_MASK 0x7
	36	/* 2nd byte in the tag */
	37	#define BRCM_IG_TE_MASK 0x3
	38	#define BRCM_IG_TS_SHIFT 7
	39	/* 3rd byte in the tag */
	40	#define BRCM_IG_DSTMAP2_MASK 1
	41	#define BRCM_IG_DSTMAP1_MASK 0xff
	42
	43	/* Egress fields */
	44
	45	/* 2nd byte in the tag */
	46	#define BRCM_EG_CID_MASK 0xff
	47
	48	/* 3rd byte in the tag */
	49	#define BRCM_EG_RC_MASK 0xff
	50	#define BRCM_EG_RC_RSVD (3 << 6)
	51	#define BRCM_EG_RC_EXCEPTION (1 << 5)
	52	#define BRCM_EG_RC_PROT_SNOOP (1 << 4)
	53	#define BRCM_EG_RC_PROT_TERM (1 << 3)
	54	#define BRCM_EG_RC_SWITCH (1 << 2)
	55	#define BRCM_EG_RC_MAC_LEARN (1 << 1)
	56	#define BRCM_EG_RC_MIRROR (1 << 0)
	57	#define BRCM_EG_TC_SHIFT 5
	58	#define BRCM_EG_TC_MASK 0x7
	59	#define BRCM_EG_PID_MASK 0x1f
	60
	61	static netdev_tx_t brcm_tag_xmit(struct sk_buff skb, struct net_device dev)
	62	{
	63	struct dsa_slave_priv *p = netdev_priv(dev);
	64	u8 *brcm_tag;
	65
	66	dev->stats.tx_packets++;
	67	dev->stats.tx_bytes += skb->len;
	68
	69	if (skb_cow_head(skb, BRCM_TAG_LEN) < 0)
	70	goto out_free;
	71
	72	skb_push(skb, BRCM_TAG_LEN);
	73
	74	memmove(skb->data, skb->data + BRCM_TAG_LEN, 2 * ETH_ALEN);
	75
	76	/* Build the tag after the MAC Source Address */
	77	brcm_tag = skb->data + 2 * ETH_ALEN;
78
79	/* Set the ingress opcode, traffic class, tag enforcment is
80	* deprecated
81	*/
82	brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) \|
83	((skb->priority << BRCM_IG_TC_SHIFT) & BRCM_IG_TC_MASK);
84	brcm_tag[1] = 0;
85	brcm_tag[2] = 0;
86	if (p->port == 8)
87	brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
88	brcm_tag[3] = (1 << p->port) & BRCM_IG_DSTMAP1_MASK;
89
90	/* Queue the SKB for transmission on the parent interface, but
91	* do not modify its EtherType
92	*/
5037d532 FF	93	skb->dev = p->parent->dst->master_netdev;
	94	dev_queue_xmit(skb);
	95
	96	return NETDEV_TX_OK;
	97
	98	out_free:
	99	kfree_skb(skb);
	100	return NETDEV_TX_OK;
	101	}
	102
	103	static int brcm_tag_rcv(struct sk_buff skb, struct net_device dev,
	104	struct packet_type pt, struct net_device orig_dev)
	105	{
	106	struct dsa_switch_tree *dst = dev->dsa_ptr;
	107	struct dsa_switch *ds;
	108	int source_port;
	109	u8 *brcm_tag;
	110
	111	if (unlikely(dst == NULL))
	112	goto out_drop;
	113
	114	ds = dst->ds[0];
	115
	116	skb = skb_unshare(skb, GFP_ATOMIC);
	117	if (skb == NULL)
	118	goto out;
	119
	120	if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
	121	goto out_drop;
	122
	123	/* skb->data points to the EtherType, the tag is right before it */
	124	brcm_tag = skb->data - 2;
	125
	126	/* The opcode should never be different than 0b000 */
	127	if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
	128	goto out_drop;
	129
	130	/* We should never see a reserved reason code without knowing how to
	131	* handle it
	132	*/
	133	WARN_ON(brcm_tag[2] & BRCM_EG_RC_RSVD);
	134
	135	/* Locate which port this is coming from */
	136	source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
	137
	138	/* Validate port against switch setup, either the port is totally */
	139	if (source_port >= DSA_MAX_PORTS \|\| ds->ports[source_port] == NULL)
	140	goto out_drop;
	141
	142	/* Remove Broadcom tag and update checksum */
	143	skb_pull_rcsum(skb, BRCM_TAG_LEN);
	144
	145	/* Move the Ethernet DA and SA */
	146	memmove(skb->data - ETH_HLEN,
	147	skb->data - ETH_HLEN - BRCM_TAG_LEN,
	148	2 * ETH_ALEN);
	149
	150	skb_push(skb, ETH_HLEN);
	151	skb->pkt_type = PACKET_HOST;
	152	skb->dev = ds->ports[source_port];
	153	skb->protocol = eth_type_trans(skb, skb->dev);
	154
	155	skb->dev->stats.rx_packets++;
	156	skb->dev->stats.rx_bytes += skb->len;
157
158	netif_receive_skb(skb);
159
160	return 0;
161
162	out_drop:
163	kfree_skb(skb);
164	out:
165	return 0;
166	}
167
168	const struct dsa_device_ops brcm_netdev_ops = {
169	.xmit = brcm_tag_xmit,
170	.rcv = brcm_tag_rcv,
171	};