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         return;
 116 }
 117
 118 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 119 {
 120         struct caif_device_entry *caifd =
 121             container_of(layer, struct caif_device_entry, layer);
 122         struct sk_buff *skb, *skb2;
 123         int ret = -EINVAL;
 124         skb = cfpkt_tonative(pkt);
 125         skb->dev = caifd->netdev;
 126         /*
 127          * Don't allow SKB to be destroyed upon error, but signal resend
 128          * notification to clients. We can't rely on the return value as
 129          * congestion (NET_XMIT_CN) sometimes drops the packet, sometimes don't.
 130          */
 131         if (netif_queue_stopped(caifd->netdev))
 132                 return -EAGAIN;
 133         skb2 = skb_get(skb);
 134
 135         ret = dev_queue_xmit(skb2);
 136
 137         if (!ret)
 138                 kfree_skb(skb);
 139         else
 140                 return -EAGAIN;
 141
 142         return 0;
 143 }
 144
 145 static int modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
 146 {
 147         struct caif_device_entry *caifd;
 148         struct caif_dev_common *caifdev;
 149         caifd = container_of(layr, struct caif_device_entry, layer);
 150         caifdev = netdev_priv(caifd->netdev);
 151         if (ctrl == _CAIF_MODEMCMD_PHYIF_USEFULL) {
 152                 atomic_set(&caifd->in_use, 1);
 153                 wake_up_interruptible(&caifd->event);
 154
 155         } else if (ctrl == _CAIF_MODEMCMD_PHYIF_USELESS) {
 156                 atomic_set(&caifd->in_use, 0);
 157                 wake_up_interruptible(&caifd->event);
 158         }
 159         return 0;
 160 }
 161
 162 /*
 163  * Stuff received packets to associated sockets.
 164  * On error, returns non-zero and releases the skb.
 165  */
 166 static int receive(struct sk_buff *skb, struct net_device *dev,
 167                    struct packet_type *pkttype, struct net_device *orig_dev)
 168 {
 169         struct net *net;
 170         struct cfpkt *pkt;
 171         struct caif_device_entry *caifd;
 172         net = dev_net(dev);
 173         pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
 174         caifd = caif_get(dev);
 175         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 176                 return NET_RX_DROP;
 177
 178         if (caifd->layer.up->receive(caifd->layer.up, pkt))
 179                 return NET_RX_DROP;
 180
 181         return 0;
 182 }
 183
 184 static struct packet_type caif_packet_type __read_mostly = {
 185         .type = cpu_to_be16(ETH_P_CAIF),
 186         .func = receive,
 187 };
 188
 189 static void dev_flowctrl(struct net_device *dev, int on)
 190 {
 191         struct caif_device_entry *caifd = caif_get(dev);
 192         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 193                 return;
 194
 195         caifd->layer.up->ctrlcmd(caifd->layer.up,
 196                                  on ?
 197                                  _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
 198                                  _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
 199                                  caifd->layer.id);
 200 }
 201
 202 /* notify Caif of device events */
 203 static int caif_device_notify(struct notifier_block *me, unsigned long what,
 204                               void *arg)
 205 {
 206         struct net_device *dev = arg;
 207         struct caif_device_entry *caifd = NULL;
 208         struct caif_dev_common *caifdev;
 209         enum cfcnfg_phy_preference pref;
 210         int res = -EINVAL;
 211         enum cfcnfg_phy_type phy_type;
 212
 213         if (dev->type != ARPHRD_CAIF)
 214                 return 0;
 215
 216         switch (what) {
 217         case NETDEV_REGISTER:
 218                 pr_info("CAIF: %s():register %s\n", __func__, dev->name);
 219                 caifd = caif_device_alloc(dev);
 220                 if (caifd == NULL)
 221                         break;
 222                 caifdev = netdev_priv(dev);
 223                 caifdev->flowctrl = dev_flowctrl;
 224                 atomic_set(&caifd->state, what);
 225                 res = 0;
 226                 break;
 227
 228         case NETDEV_UP:
 229                 pr_info("CAIF: %s(): up %s\n", __func__, dev->name);
 230                 caifd = caif_get(dev);
 231                 if (caifd == NULL)
 232                         break;
 233                 caifdev = netdev_priv(dev);
 234                 if (atomic_read(&caifd->state) == NETDEV_UP) {
 235                         pr_info("CAIF: %s():%s already up\n",
 236                                 __func__, dev->name);
 237                         break;
 238                 }
 239                 atomic_set(&caifd->state, what);
 240                 caifd->layer.transmit = transmit;
 241                 caifd->layer.modemcmd = modemcmd;
 242
 243                 if (caifdev->use_frag)
 244                         phy_type = CFPHYTYPE_FRAG;
 245                 else
 246                         phy_type = CFPHYTYPE_CAIF;
 247
 248                 switch (caifdev->link_select) {
 249                 case CAIF_LINK_HIGH_BANDW:
 250                         pref = CFPHYPREF_LOW_LAT;
 251                         break;
 252                 case CAIF_LINK_LOW_LATENCY:
 253                         pref = CFPHYPREF_HIGH_BW;
 254                         break;
 255                 default:
 256                         pref = CFPHYPREF_HIGH_BW;
 257                         break;
 258                 }
 259
 260                 cfcnfg_add_phy_layer(get_caif_conf(),
 261                                      phy_type,
 262                                      dev,
 263                                      &caifd->layer,
 264                                      &caifd->phyid,
 265                                      pref,
 266                                      caifdev->use_fcs,
 267                                      caifdev->use_stx);
 268                 strncpy(caifd->layer.name, dev->name,
 269                         sizeof(caifd->layer.name) - 1);
 270                 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
 271                 break;
 272
 273         case NETDEV_GOING_DOWN:
 274                 caifd = caif_get(dev);
 275                 if (caifd == NULL)
 276                         break;
 277                 pr_info("CAIF: %s():going down %s\n", __func__, dev->name);
 278
 279                 if (atomic_read(&caifd->state) == NETDEV_GOING_DOWN ||
 280                         atomic_read(&caifd->state) == NETDEV_DOWN)
 281                         break;
 282
 283                 atomic_set(&caifd->state, what);
 284                 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 285                         return -EINVAL;
 286                 caifd->layer.up->ctrlcmd(caifd->layer.up,
 287                                          _CAIF_CTRLCMD_PHYIF_DOWN_IND,
 288                                          caifd->layer.id);
 289                 res = wait_event_interruptible_timeout(caifd->event,
 290                                         atomic_read(&caifd->in_use) == 0,
 291                                         TIMEOUT);
 292                 break;
 293
 294         case NETDEV_DOWN:
 295                 caifd = caif_get(dev);
 296                 if (caifd == NULL)
 297                         break;
 298                 pr_info("CAIF: %s(): down %s\n", __func__, dev->name);
 299                 if (atomic_read(&caifd->in_use))
 300                         pr_warning("CAIF: %s(): "
 301                                    "Unregistering an active CAIF device: %s\n",
 302                                    __func__, dev->name);
 303                 cfcnfg_del_phy_layer(get_caif_conf(), &caifd->layer);
 304                 atomic_set(&caifd->state, what);
 305                 break;
 306
 307         case NETDEV_UNREGISTER:
 308                 caifd = caif_get(dev);
 309                 pr_info("CAIF: %s(): unregister %s\n", __func__, dev->name);
 310                 atomic_set(&caifd->state, what);
 311                 caif_device_destroy(dev);
 312                 break;
 313         }
 314         return 0;
 315 }
 316
 317 static struct notifier_block caif_device_notifier = {
 318         .notifier_call = caif_device_notify,
 319         .priority = 0,
 320 };
 321
 322
 323 struct cfcnfg *get_caif_conf(void)
 324 {
 325         return cfg;
 326 }
 327 EXPORT_SYMBOL(get_caif_conf);
 328
 329 int caif_connect_client(struct caif_connect_request *conn_req,
 330                            struct cflayer *client_layer)
 331 {
 332         struct cfctrl_link_param param;
 333         if (connect_req_to_link_param(get_caif_conf(), conn_req, &param) == 0)
 334                 /* Hook up the adaptation layer. */
 335                 return cfcnfg_add_adaptation_layer(get_caif_conf(),
 336                                                 &param, client_layer);
 337
 338         return -EINVAL;
 339
 340         caif_assert(0);
 341 }
 342 EXPORT_SYMBOL(caif_connect_client);
 343
 344 int caif_disconnect_client(struct cflayer *adap_layer)
 345 {
 346         return cfcnfg_del_adapt_layer(get_caif_conf(), adap_layer);
 347 }
 348 EXPORT_SYMBOL(caif_disconnect_client);
 349
 350 /* Per-namespace Caif devices handling */
 351 static int caif_init_net(struct net *net)
 352 {
 353         struct caif_net *caifn = net_generic(net, caif_net_id);
 354         INIT_LIST_HEAD(&caifn->caifdevs.list);
 355         spin_lock_init(&caifn->caifdevs.lock);
 356         return 0;
 357 }
 358
 359 static void caif_exit_net(struct net *net)
 360 {
 361         struct net_device *dev;
 362         int res;
 363         rtnl_lock();
 364         for_each_netdev(net, dev) {
 365                 if (dev->type != ARPHRD_CAIF)
 366                         continue;
 367                 res = dev_close(dev);
 368                 caif_device_destroy(dev);
 369         }
 370         rtnl_unlock();
 371 }
 372
 373 static struct pernet_operations caif_net_ops = {
 374         .init = caif_init_net,
 375         .exit = caif_exit_net,
 376         .id   = &caif_net_id,
 377         .size = sizeof(struct caif_net),
 378 };
 379
 380 /* Initialize Caif devices list */
 381 static int __init caif_device_init(void)
 382 {
 383         int result;
 384         cfg = cfcnfg_create();
 385         if (!cfg) {
 386                 pr_warning("CAIF: %s(): can't create cfcnfg.\n", __func__);
 387                 goto err_cfcnfg_create_failed;
 388         }
 389         result = register_pernet_device(&caif_net_ops);
 390
 391         if (result) {
 392                 kfree(cfg);
 393                 cfg = NULL;
 394                 return result;
 395         }
 396         dev_add_pack(&caif_packet_type);
 397         register_netdevice_notifier(&caif_device_notifier);
 398
 399         return result;
 400 err_cfcnfg_create_failed:
 401         return -ENODEV;
 402 }
 403
 404 static void __exit caif_device_exit(void)
 405 {
 406         dev_remove_pack(&caif_packet_type);
 407         unregister_pernet_device(&caif_net_ops);
 408         unregister_netdevice_notifier(&caif_device_notifier);
 409         cfcnfg_remove(cfg);
 410 }
 411
 412 module_init(caif_device_init);
 413 module_exit(caif_device_exit);