net/caif/caif_dev.c

   1 /*
   2  * CAIF Interface registration.
   3  * Copyright (C) ST-Ericsson AB 2010
   4  * Author:      Sjur Brendeland/sjur.brandeland@stericsson.com
   5  * License terms: GNU General Public License (GPL) version 2
   6  *
   7  * Borrowed heavily from file: pn_dev.c. Thanks to
   8  *  Remi Denis-Courmont <remi.denis-courmont@nokia.com>
   9  *  and Sakari Ailus <sakari.ailus@nokia.com>
  10  */
  11
  12 #include <linux/version.h>
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/net.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/sched.h>
  20 #include <linux/wait.h>
  21 #include <net/netns/generic.h>
  22 #include <net/net_namespace.h>
  23 #include <net/pkt_sched.h>
  24 #include <net/caif/caif_device.h>
  25 #include <net/caif/caif_dev.h>
  26 #include <net/caif/caif_layer.h>
  27 #include <net/caif/cfpkt.h>
  28 #include <net/caif/cfcnfg.h>
  29
  30 MODULE_LICENSE("GPL");
  31 #define TIMEOUT (HZ*5)
  32
  33 /* Used for local tracking of the CAIF net devices */
  34 struct caif_device_entry {
  35         struct cflayer layer;
  36         struct list_head list;
  37         atomic_t in_use;
  38         atomic_t state;
  39         u16 phyid;
  40         struct net_device *netdev;
  41         wait_queue_head_t event;
  42 };
  43
  44 struct caif_device_entry_list {
  45         struct list_head list;
  46         /* Protects simulanous deletes in list */
  47         spinlock_t lock;
  48 };
  49
  50 struct caif_net {
  51         struct caif_device_entry_list caifdevs;
  52 };
  53
  54 static int caif_net_id;
  55 static struct cfcnfg *cfg;
  56
  57 static struct caif_device_entry_list *caif_device_list(struct net *net)
  58 {
  59         struct caif_net *caifn;
  60         BUG_ON(!net);
  61         caifn = net_generic(net, caif_net_id);
  62         BUG_ON(!caifn);
  63         return &caifn->caifdevs;
  64 }
  65
  66 /* Allocate new CAIF device. */
  67 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
  68 {
  69         struct caif_device_entry_list *caifdevs;
  70         struct caif_device_entry *caifd;
  71         caifdevs = caif_device_list(dev_net(dev));
  72         BUG_ON(!caifdevs);
  73         caifd = kzalloc(sizeof(*caifd), GFP_ATOMIC);
  74         if (!caifd)
  75                 return NULL;
  76         caifd->netdev = dev;
  77         list_add(&caifd->list, &caifdevs->list);
  78         init_waitqueue_head(&caifd->event);
  79         return caifd;
  80 }
  81
  82 static struct caif_device_entry *caif_get(struct net_device *dev)
  83 {
  84         struct caif_device_entry_list *caifdevs =
  85             caif_device_list(dev_net(dev));
  86         struct caif_device_entry *caifd;
  87         BUG_ON(!caifdevs);
  88         list_for_each_entry(caifd, &caifdevs->list, list) {
  89                 if (caifd->netdev == dev)
  90                         return caifd;
  91         }
  92         return NULL;
  93 }
  94
  95 static void caif_device_destroy(struct net_device *dev)
  96 {
  97         struct caif_device_entry_list *caifdevs =
  98             caif_device_list(dev_net(dev));
  99         struct caif_device_entry *caifd;
 100         ASSERT_RTNL();
 101         if (dev->type != ARPHRD_CAIF)
 102                 return;
 103
 104         spin_lock_bh(&caifdevs->lock);
 105         caifd = caif_get(dev);
 106         if (caifd == NULL) {
 107                 spin_unlock_bh(&caifdevs->lock);
 108                 return;
 109         }
 110
 111         list_del(&caifd->list);
 112         spin_unlock_bh(&caifdevs->lock);
 113
 114         kfree(caifd);
 115 }
 116
 117 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 118 {
 119         struct caif_device_entry *caifd =
 120             container_of(layer, struct caif_device_entry, layer);
 121         struct sk_buff *skb, *skb2;
 122         int ret = -EINVAL;
 123         skb = cfpkt_tonative(pkt);
 124         skb->dev = caifd->netdev;
 125         /*
 126          * Don't allow SKB to be destroyed upon error, but signal resend
 127          * notification to clients. We can't rely on the return value as
 128          * congestion (NET_XMIT_CN) sometimes drops the packet, sometimes don't.
 129          */
 130         if (netif_queue_stopped(caifd->netdev))
 131                 return -EAGAIN;
 132         skb2 = skb_get(skb);
 133
 134         ret = dev_queue_xmit(skb2);
 135
 136         if (!ret)
 137                 kfree_skb(skb);
 138         else
 139                 return -EAGAIN;
 140
 141         return 0;
 142 }
 143
 144 static int modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
 145 {
 146         struct caif_device_entry *caifd;
 147         struct caif_dev_common *caifdev;
 148         caifd = container_of(layr, struct caif_device_entry, layer);
 149         caifdev = netdev_priv(caifd->netdev);
 150         if (ctrl == _CAIF_MODEMCMD_PHYIF_USEFULL) {
 151                 atomic_set(&caifd->in_use, 1);
 152                 wake_up_interruptible(&caifd->event);
 153
 154         } else if (ctrl == _CAIF_MODEMCMD_PHYIF_USELESS) {
 155                 atomic_set(&caifd->in_use, 0);
 156                 wake_up_interruptible(&caifd->event);
 157         }
 158         return 0;
 159 }
 160
 161 /*
 162  * Stuff received packets to associated sockets.
 163  * On error, returns non-zero and releases the skb.
 164  */
 165 static int receive(struct sk_buff *skb, struct net_device *dev,
 166                    struct packet_type *pkttype, struct net_device *orig_dev)
 167 {
 168         struct net *net;
 169         struct cfpkt *pkt;
 170         struct caif_device_entry *caifd;
 171         net = dev_net(dev);
 172         pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
 173         caifd = caif_get(dev);
 174         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 175                 return NET_RX_DROP;
 176
 177         if (caifd->layer.up->receive(caifd->layer.up, pkt))
 178                 return NET_RX_DROP;
 179
 180         return 0;
 181 }
 182
 183 static struct packet_type caif_packet_type __read_mostly = {
 184         .type = cpu_to_be16(ETH_P_CAIF),
 185         .func = receive,
 186 };
 187
 188 static void dev_flowctrl(struct net_device *dev, int on)
 189 {
 190         struct caif_device_entry *caifd = caif_get(dev);
 191         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 192                 return;
 193
 194         caifd->layer.up->ctrlcmd(caifd->layer.up,
 195                                  on ?
 196                                  _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
 197                                  _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
 198                                  caifd->layer.id);
 199 }
 200
 201 /* notify Caif of device events */
 202 static int caif_device_notify(struct notifier_block *me, unsigned long what,
 203                               void *arg)
 204 {
 205         struct net_device *dev = arg;
 206         struct caif_device_entry *caifd = NULL;
 207         struct caif_dev_common *caifdev;
 208         enum cfcnfg_phy_preference pref;
 209         int res = -EINVAL;
 210         enum cfcnfg_phy_type phy_type;
 211
 212         if (dev->type != ARPHRD_CAIF)
 213                 return 0;
 214
 215         switch (what) {
 216         case NETDEV_REGISTER:
 217                 pr_info("CAIF: %s():register %s\n", __func__, dev->name);
 218                 caifd = caif_device_alloc(dev);
 219                 if (caifd == NULL)
 220                         break;
 221                 caifdev = netdev_priv(dev);
 222                 caifdev->flowctrl = dev_flowctrl;
 223                 atomic_set(&caifd->state, what);
 224                 res = 0;
 225                 break;
 226
 227         case NETDEV_UP:
 228                 pr_info("CAIF: %s(): up %s\n", __func__, dev->name);
 229                 caifd = caif_get(dev);
 230                 if (caifd == NULL)
 231                         break;
 232                 caifdev = netdev_priv(dev);
 233                 if (atomic_read(&caifd->state) == NETDEV_UP) {
 234                         pr_info("CAIF: %s():%s already up\n",
 235                                 __func__, dev->name);
 236                         break;
 237                 }
 238                 atomic_set(&caifd->state, what);
 239                 caifd->layer.transmit = transmit;
 240                 caifd->layer.modemcmd = modemcmd;
 241
 242                 if (caifdev->use_frag)
 243                         phy_type = CFPHYTYPE_FRAG;
 244                 else
 245                         phy_type = CFPHYTYPE_CAIF;
 246
 247                 switch (caifdev->link_select) {
 248                 case CAIF_LINK_HIGH_BANDW:
 249                         pref = CFPHYPREF_HIGH_BW;
 250                         break;
 251                 case CAIF_LINK_LOW_LATENCY:
 252                         pref = CFPHYPREF_LOW_LAT;
 253                         break;
 254                 default:
 255                         pref = CFPHYPREF_HIGH_BW;
 256                         break;
 257                 }
 258
 259                 cfcnfg_add_phy_layer(get_caif_conf(),
 260                                      phy_type,
 261                                      dev,
 262                                      &caifd->layer,
 263                                      &caifd->phyid,
 264                                      pref,
 265                                      caifdev->use_fcs,
 266                                      caifdev->use_stx);
 267                 strncpy(caifd->layer.name, dev->name,
 268                         sizeof(caifd->layer.name) - 1);
 269                 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
 270                 break;
 271
 272         case NETDEV_GOING_DOWN:
 273                 caifd = caif_get(dev);
 274                 if (caifd == NULL)
 275                         break;
 276                 pr_info("CAIF: %s():going down %s\n", __func__, dev->name);
 277
 278                 if (atomic_read(&caifd->state) == NETDEV_GOING_DOWN ||
 279                         atomic_read(&caifd->state) == NETDEV_DOWN)
 280                         break;
 281
 282                 atomic_set(&caifd->state, what);
 283                 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 284                         return -EINVAL;
 285                 caifd->layer.up->ctrlcmd(caifd->layer.up,
 286                                          _CAIF_CTRLCMD_PHYIF_DOWN_IND,
 287                                          caifd->layer.id);
 288                 res = wait_event_interruptible_timeout(caifd->event,
 289                                         atomic_read(&caifd->in_use) == 0,
 290                                         TIMEOUT);
 291                 break;
 292
 293         case NETDEV_DOWN:
 294                 caifd = caif_get(dev);
 295                 if (caifd == NULL)
 296                         break;
 297                 pr_info("CAIF: %s(): down %s\n", __func__, dev->name);
 298                 if (atomic_read(&caifd->in_use))
 299                         pr_warning("CAIF: %s(): "
 300                                    "Unregistering an active CAIF device: %s\n",
 301                                    __func__, dev->name);
 302                 cfcnfg_del_phy_layer(get_caif_conf(), &caifd->layer);
 303                 atomic_set(&caifd->state, what);
 304                 break;
 305
 306         case NETDEV_UNREGISTER:
 307                 caifd = caif_get(dev);
 308                 pr_info("CAIF: %s(): unregister %s\n", __func__, dev->name);
 309                 atomic_set(&caifd->state, what);
 310                 caif_device_destroy(dev);
 311                 break;
 312         }
 313         return 0;
 314 }
 315
 316 static struct notifier_block caif_device_notifier = {
 317         .notifier_call = caif_device_notify,
 318         .priority = 0,
 319 };
 320
 321
 322 struct cfcnfg *get_caif_conf(void)
 323 {
 324         return cfg;
 325 }
 326 EXPORT_SYMBOL(get_caif_conf);
 327
 328 int caif_connect_client(struct caif_connect_request *conn_req,
 329                            struct cflayer *client_layer)
 330 {
 331         struct cfctrl_link_param param;
 332         int ret;
 333         ret = connect_req_to_link_param(get_caif_conf(), conn_req, &param);
 334         if (ret)
 335                 return ret;
 336         /* Hook up the adaptation layer. */
 337         return cfcnfg_add_adaptation_layer(get_caif_conf(),
 338                                                 &param, client_layer);
 339 }
 340 EXPORT_SYMBOL(caif_connect_client);
 341
 342 int caif_disconnect_client(struct cflayer *adap_layer)
 343 {
 344        return cfcnfg_disconn_adapt_layer(get_caif_conf(), adap_layer);
 345 }
 346 EXPORT_SYMBOL(caif_disconnect_client);
 347
 348 void caif_release_client(struct cflayer *adap_layer)
 349 {
 350        cfcnfg_release_adap_layer(adap_layer);
 351 }
 352 EXPORT_SYMBOL(caif_release_client);
 353
 354 /* Per-namespace Caif devices handling */
 355 static int caif_init_net(struct net *net)
 356 {
 357         struct caif_net *caifn = net_generic(net, caif_net_id);
 358         INIT_LIST_HEAD(&caifn->caifdevs.list);
 359         spin_lock_init(&caifn->caifdevs.lock);
 360         return 0;
 361 }
 362
 363 static void caif_exit_net(struct net *net)
 364 {
 365         struct net_device *dev;
 366         int res;
 367         rtnl_lock();
 368         for_each_netdev(net, dev) {
 369                 if (dev->type != ARPHRD_CAIF)
 370                         continue;
 371                 res = dev_close(dev);
 372                 caif_device_destroy(dev);
 373         }
 374         rtnl_unlock();
 375 }
 376
 377 static struct pernet_operations caif_net_ops = {
 378         .init = caif_init_net,
 379         .exit = caif_exit_net,
 380         .id   = &caif_net_id,
 381         .size = sizeof(struct caif_net),
 382 };
 383
 384 /* Initialize Caif devices list */
 385 static int __init caif_device_init(void)
 386 {
 387         int result;
 388         cfg = cfcnfg_create();
 389         if (!cfg) {
 390                 pr_warning("CAIF: %s(): can't create cfcnfg.\n", __func__);
 391                 goto err_cfcnfg_create_failed;
 392         }
 393         result = register_pernet_device(&caif_net_ops);
 394
 395         if (result) {
 396                 kfree(cfg);
 397                 cfg = NULL;
 398                 return result;
 399         }
 400         dev_add_pack(&caif_packet_type);
 401         register_netdevice_notifier(&caif_device_notifier);
 402
 403         return result;
 404 err_cfcnfg_create_failed:
 405         return -ENODEV;
 406 }
 407
 408 static void __exit caif_device_exit(void)
 409 {
 410         dev_remove_pack(&caif_packet_type);
 411         unregister_pernet_device(&caif_net_ops);
 412         unregister_netdevice_notifier(&caif_device_notifier);
 413         cfcnfg_remove(cfg);
 414 }
 415
 416 module_init(caif_device_init);
 417 module_exit(caif_device_exit);