drivers/net/ethernet/chelsio/cxgb3/l2t.h

   1 /*
   2  * Copyright (c) 2003-2008 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 <linux/atomic.h>
  38
  39 enum {
  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
  46 struct neighbour;
  47 struct 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  */
  57 struct 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_head arpq;       /* queue of packets awaiting resolution */
  68         spinlock_t lock;
  69         atomic_t refcnt;        /* entry reference count */
  70         u8 dmac[6];             /* neighbour's MAC address */
  71 };
  72
  73 struct l2t_data {
  74         unsigned int nentries;  /* number of entries */
  75         struct l2t_entry *rover;        /* starting point for next allocation */
  76         atomic_t nfree;         /* number of free entries */
  77         rwlock_t lock;
  78         struct l2t_entry l2tab[0];
  79         struct rcu_head rcu_head;       /* to handle rcu cleanup */
  80 };
  81
  82 typedef 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  */
  88 struct 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
  94 static 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(cdev) (rcu_dereference((cdev)->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
 110 void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e);
 111 void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh);
 112 struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst,
 113                              struct net_device *dev);
 114 int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
 115                      struct l2t_entry *e);
 116 void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e);
 117 struct l2t_data *t3_init_l2t(unsigned int l2t_capacity);
 118 void t3_free_l2t(struct l2t_data *d);
 119
 120 int cxgb3_ofld_send(struct t3cdev *dev, struct sk_buff *skb);
 121
 122 static 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
 130 static inline void l2t_release(struct t3cdev *t, struct l2t_entry *e)
 131 {
 132         struct l2t_data *d;
 133
 134         rcu_read_lock();
 135         d = L2DATA(t);
 136
 137         if (atomic_dec_and_test(&e->refcnt) && d)
 138                 t3_l2e_free(d, e);
 139
 140         rcu_read_unlock();
 141 }
 142
 143 static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
 144 {
 145         if (d && atomic_add_return(1, &e->refcnt) == 1) /* 0 -> 1 transition */
 146                 atomic_dec(&d->nfree);
 147 }
 148
 149 #endif