1/*
2 * Copyright (c) 2003-2007 Chelsio, Inc. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 */
32#ifndef _CHELSIO_L2T_H
33#define _CHELSIO_L2T_H
34
35#include <linux/spinlock.h>
36#include "t3cdev.h"
37#include <asm/atomic.h>
38
39enum {
40	L2T_STATE_VALID,	/* entry is up to date */
41	L2T_STATE_STALE,	/* entry may be used but needs revalidation */
42	L2T_STATE_RESOLVING,	/* entry needs address resolution */
43	L2T_STATE_UNUSED	/* entry not in use */
44};
45
46struct neighbour;
47struct sk_buff;
48
49/*
50 * Each L2T entry plays multiple roles.  First of all, it keeps state for the
51 * corresponding entry of the HW L2 table and maintains a queue of offload
52 * packets awaiting address resolution.  Second, it is a node of a hash table
53 * chain, where the nodes of the chain are linked together through their next
54 * pointer.  Finally, each node is a bucket of a hash table, pointing to the
55 * first element in its chain through its first pointer.
56 */
57struct l2t_entry {
58	u16 state;		/* entry state */
59	u16 idx;		/* entry index */
60	u32 addr;		/* dest IP address */
61	int ifindex;		/* neighbor's net_device's ifindex */
62	u16 smt_idx;		/* SMT index */
63	u16 vlan;		/* VLAN TCI (id: bits 0-11, prio: 13-15 */
64	struct neighbour *neigh;	/* associated neighbour */
65	struct l2t_entry *first;	/* start of hash chain */
66	struct l2t_entry *next;	/* next l2t_entry on chain */
67	struct sk_buff *arpq_head;	/* queue of packets awaiting resolution */
68	struct sk_buff *arpq_tail;
69	spinlock_t lock;
70	atomic_t refcnt;	/* entry reference count */
71	u8 dmac[6];		/* neighbour's MAC address */
72};
73
74struct l2t_data {
75	unsigned int nentries;	/* number of entries */
76	struct l2t_entry *rover;	/* starting point for next allocation */
77	atomic_t nfree;		/* number of free entries */
78	rwlock_t lock;
79	struct l2t_entry l2tab[0];
80};
81
82typedef void (*arp_failure_handler_func)(struct t3cdev * dev,
83					 struct sk_buff * skb);
84
85/*
86 * Callback stored in an skb to handle address resolution failure.
87 */
88struct l2t_skb_cb {
89	arp_failure_handler_func arp_failure_handler;
90};
91
92#define L2T_SKB_CB(skb) ((struct l2t_skb_cb *)(skb)->cb)
93
94static inline void set_arp_failure_handler(struct sk_buff *skb,
95					   arp_failure_handler_func hnd)
96{
97	L2T_SKB_CB(skb)->arp_failure_handler = hnd;
98}
99
100/*
101 * Getting to the L2 data from an offload device.
102 */
103#define L2DATA(dev) ((dev)->l2opt)
104
105#define W_TCB_L2T_IX    0
106#define S_TCB_L2T_IX    7
107#define M_TCB_L2T_IX    0x7ffULL
108#define V_TCB_L2T_IX(x) ((x) << S_TCB_L2T_IX)
109
110void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e);
111void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh);
112struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct neighbour *neigh,
113			     struct net_device *dev);
114int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
115		     struct l2t_entry *e);
116void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e);
117struct l2t_data *t3_init_l2t(unsigned int l2t_capacity);
118void t3_free_l2t(struct l2t_data *d);
119
120int cxgb3_ofld_send(struct t3cdev *dev, struct sk_buff *skb);
121
122static inline int l2t_send(struct t3cdev *dev, struct sk_buff *skb,
123			   struct l2t_entry *e)
124{
125	if (likely(e->state == L2T_STATE_VALID))
126		return cxgb3_ofld_send(dev, skb);
127	return t3_l2t_send_slow(dev, skb, e);
128}
129
130static inline void l2t_release(struct l2t_data *d, struct l2t_entry *e)
131{
132	if (atomic_dec_and_test(&e->refcnt))
133		t3_l2e_free(d, e);
134}
135
136static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
137{
138	if (atomic_add_return(1, &e->refcnt) == 1)	/* 0 -> 1 transition */
139		atomic_dec(&d->nfree);
140}
141
142#endif
143