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 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
  13
  14 #include <linux/version.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/net.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/sched.h>
  22 #include <linux/wait.h>
  23 #include <net/netns/generic.h>
  24 #include <net/net_namespace.h>
  25 #include <net/pkt_sched.h>
  26 #include <net/caif/caif_device.h>
  27 #include <net/caif/caif_dev.h>
  28 #include <net/caif/caif_layer.h>
  29 #include <net/caif/cfpkt.h>
  30 #include <net/caif/cfcnfg.h>
  31
  32 MODULE_LICENSE("GPL");
  33 #define TIMEOUT (HZ*5)
  34
  35 /* Used for local tracking of the CAIF net devices */
  36 struct caif_device_entry {
  37         struct cflayer layer;
  38         struct list_head list;
  39         atomic_t in_use;
  40         atomic_t state;
  41         u16 phyid;
  42         struct net_device *netdev;
  43         wait_queue_head_t event;
  44 };
  45
  46 struct caif_device_entry_list {
  47         struct list_head list;
  48         /* Protects simulanous deletes in list */
  49         spinlock_t lock;
  50 };
  51
  52 struct caif_net {
  53         struct caif_device_entry_list caifdevs;
  54 };
  55
  56 static int caif_net_id;
  57 static struct cfcnfg *cfg;
  58
  59 static struct caif_device_entry_list *caif_device_list(struct net *net)
  60 {
  61         struct caif_net *caifn;
  62         BUG_ON(!net);
  63         caifn = net_generic(net, caif_net_id);
  64         BUG_ON(!caifn);
  65         return &caifn->caifdevs;
  66 }
  67
  68 /* Allocate new CAIF device. */
  69 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
  70 {
  71         struct caif_device_entry_list *caifdevs;
  72         struct caif_device_entry *caifd;
  73         caifdevs = caif_device_list(dev_net(dev));
  74         BUG_ON(!caifdevs);
  75         caifd = kzalloc(sizeof(*caifd), GFP_ATOMIC);
  76         if (!caifd)
  77                 return NULL;
  78         caifd->netdev = dev;
  79         list_add(&caifd->list, &caifdevs->list);
  80         init_waitqueue_head(&caifd->event);
  81         return caifd;
  82 }
  83
  84 static struct caif_device_entry *caif_get(struct net_device *dev)
  85 {
  86         struct caif_device_entry_list *caifdevs =
  87             caif_device_list(dev_net(dev));
  88         struct caif_device_entry *caifd;
  89         BUG_ON(!caifdevs);
  90         list_for_each_entry(caifd, &caifdevs->list, list) {
  91                 if (caifd->netdev == dev)
  92                         return caifd;
  93         }
  94         return NULL;
  95 }
  96
  97 static void caif_device_destroy(struct net_device *dev)
  98 {
  99         struct caif_device_entry_list *caifdevs =
 100             caif_device_list(dev_net(dev));
 101         struct caif_device_entry *caifd;
 102         ASSERT_RTNL();
 103         if (dev->type != ARPHRD_CAIF)
 104                 return;
 105
 106         spin_lock_bh(&caifdevs->lock);
 107         caifd = caif_get(dev);
 108         if (caifd == NULL) {
 109                 spin_unlock_bh(&caifdevs->lock);
 110                 return;
 111         }
 112
 113         list_del(&caifd->list);
 114         spin_unlock_bh(&caifdevs->lock);
 115
 116         kfree(caifd);
 117 }
 118
 119 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 120 {
 121         struct caif_device_entry *caifd =
 122             container_of(layer, struct caif_device_entry, layer);
 123         struct sk_buff *skb, *skb2;
 124         int ret = -EINVAL;
 125         skb = cfpkt_tonative(pkt);
 126         skb->dev = caifd->netdev;
 127         /*
 128          * Don't allow SKB to be destroyed upon error, but signal resend
 129          * notification to clients. We can't rely on the return value as
 130          * congestion (NET_XMIT_CN) sometimes drops the packet, sometimes don't.
 131          */
 132         if (netif_queue_stopped(caifd->netdev))
 133                 return -EAGAIN;
 134         skb2 = skb_get(skb);
 135
 136         ret = dev_queue_xmit(skb2);
 137
 138         if (!ret)
 139                 kfree_skb(skb);
 140         else
 141                 return -EAGAIN;
 142
 143         return 0;
 144 }
 145
 146 static int modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
 147 {
 148         struct caif_device_entry *caifd;
 149         struct caif_dev_common *caifdev;
 150         caifd = container_of(layr, struct caif_device_entry, layer);
 151         caifdev = netdev_priv(caifd->netdev);
 152         if (ctrl == _CAIF_MODEMCMD_PHYIF_USEFULL) {
 153                 atomic_set(&caifd->in_use, 1);
 154                 wake_up_interruptible(&caifd->event);
 155
 156         } else if (ctrl == _CAIF_MODEMCMD_PHYIF_USELESS) {
 157                 atomic_set(&caifd->in_use, 0);
 158                 wake_up_interruptible(&caifd->event);
 159         }
 160         return 0;
 161 }
 162
 163 /*
 164  * Stuff received packets to associated sockets.
 165  * On error, returns non-zero and releases the skb.
 166  */
 167 static int receive(struct sk_buff *skb, struct net_device *dev,
 168                    struct packet_type *pkttype, struct net_device *orig_dev)
 169 {
 170         struct net *net;
 171         struct cfpkt *pkt;
 172         struct caif_device_entry *caifd;
 173         net = dev_net(dev);
 174         pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
 175         caifd = caif_get(dev);
 176         if (!caifd || !caifd->layer.up || !caifd->layer.up->receive)
 177                 return NET_RX_DROP;
 178
 179         if (caifd->layer.up->receive(caifd->layer.up, pkt))
 180                 return NET_RX_DROP;
 181
 182         return 0;
 183 }
 184
 185 static struct packet_type caif_packet_type __read_mostly = {
 186         .type = cpu_to_be16(ETH_P_CAIF),
 187         .func = receive,
 188 };
 189
 190 static void dev_flowctrl(struct net_device *dev, int on)
 191 {
 192         struct caif_device_entry *caifd = caif_get(dev);
 193         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
 194                 return;
 195
 196         caifd->layer.up->ctrlcmd(caifd->layer.up,
 197                                  on ?
 198                                  _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
 199                                  _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
 200                                  caifd->layer.id);
 201 }
 202
 203 /* notify Caif of device events */
 204 static int caif_device_notify(struct notifier_block *me, unsigned long what,
 205                               void *arg)
 206 {
 207         struct net_device *dev = arg;
 208         struct caif_device_entry *caifd = NULL;
 209         struct caif_dev_common *caifdev;
 210         enum cfcnfg_phy_preference pref;
 211         int res = -EINVAL;
 212         enum cfcnfg_phy_type phy_type;
 213
 214         if (dev->type != ARPHRD_CAIF)
 215                 return 0;
 216
 217         switch (what) {
 218         case NETDEV_REGISTER:
 219                 netdev_info(dev, "register\n");
 220                 caifd = caif_device_alloc(dev);
 221                 if (caifd == NULL)
 222                         break;
 223                 caifdev = netdev_priv(dev);
 224                 caifdev->flowctrl = dev_flowctrl;
 225                 atomic_set(&caifd->state, what);
 226                 res = 0;
 227                 break;
 228
 229         case NETDEV_UP:
 230                 netdev_info(dev, "up\n");
 231                 caifd = caif_get(dev);
 232                 if (caifd == NULL)
 233                         break;
 234                 caifdev = netdev_priv(dev);
 235                 if (atomic_read(&caifd->state) == NETDEV_UP) {
 236                         netdev_info(dev, "already up\n");
 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_HIGH_BW;
 251                         break;
 252                 case CAIF_LINK_LOW_LATENCY:
 253                         pref = CFPHYPREF_LOW_LAT;
 254                         break;
 255                 default:
 256                         pref = CFPHYPREF_HIGH_BW;
 257                         break;
 258                 }
 259                 dev_hold(dev);
 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                 netdev_info(dev, "going down\n");
 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                 might_sleep();
 290                 res = wait_event_interruptible_timeout(caifd->event,
 291                                         atomic_read(&caifd->in_use) == 0,
 292                                         TIMEOUT);
 293                 break;
 294
 295         case NETDEV_DOWN:
 296                 caifd = caif_get(dev);
 297                 if (caifd == NULL)
 298                         break;
 299                 netdev_info(dev, "down\n");
 300                 if (atomic_read(&caifd->in_use))
 301                         netdev_warn(dev,
 302                                     "Unregistering an active CAIF device\n");
 303                 cfcnfg_del_phy_layer(get_caif_conf(), &caifd->layer);
 304                 dev_put(dev);
 305                 atomic_set(&caifd->state, what);
 306                 break;
 307
 308         case NETDEV_UNREGISTER:
 309                 caifd = caif_get(dev);
 310                 if (caifd == NULL)
 311                         break;
 312                 netdev_info(dev, "unregister\n");
 313                 atomic_set(&caifd->state, what);
 314                 caif_device_destroy(dev);
 315                 break;
 316         }
 317         return 0;
 318 }
 319
 320 static struct notifier_block caif_device_notifier = {
 321         .notifier_call = caif_device_notify,
 322         .priority = 0,
 323 };
 324
 325
 326 struct cfcnfg *get_caif_conf(void)
 327 {
 328         return cfg;
 329 }
 330 EXPORT_SYMBOL(get_caif_conf);
 331
 332 int caif_connect_client(struct caif_connect_request *conn_req,
 333                         struct cflayer *client_layer, int *ifindex,
 334                         int *headroom, int *tailroom)
 335 {
 336         struct cfctrl_link_param param;
 337         int ret;
 338         ret = connect_req_to_link_param(get_caif_conf(), conn_req, &param);
 339         if (ret)
 340                 return ret;
 341         /* Hook up the adaptation layer. */
 342         return cfcnfg_add_adaptation_layer(get_caif_conf(), &param,
 343                                         client_layer, ifindex,
 344                                         headroom, tailroom);
 345 }
 346 EXPORT_SYMBOL(caif_connect_client);
 347
 348 int caif_disconnect_client(struct cflayer *adap_layer)
 349 {
 350        return cfcnfg_disconn_adapt_layer(get_caif_conf(), adap_layer);
 351 }
 352 EXPORT_SYMBOL(caif_disconnect_client);
 353
 354 void caif_release_client(struct cflayer *adap_layer)
 355 {
 356        cfcnfg_release_adap_layer(adap_layer);
 357 }
 358 EXPORT_SYMBOL(caif_release_client);
 359
 360 /* Per-namespace Caif devices handling */
 361 static int caif_init_net(struct net *net)
 362 {
 363         struct caif_net *caifn = net_generic(net, caif_net_id);
 364         INIT_LIST_HEAD(&caifn->caifdevs.list);
 365         spin_lock_init(&caifn->caifdevs.lock);
 366         return 0;
 367 }
 368
 369 static void caif_exit_net(struct net *net)
 370 {
 371         struct net_device *dev;
 372         int res;
 373         rtnl_lock();
 374         for_each_netdev(net, dev) {
 375                 if (dev->type != ARPHRD_CAIF)
 376                         continue;
 377                 res = dev_close(dev);
 378                 caif_device_destroy(dev);
 379         }
 380         rtnl_unlock();
 381 }
 382
 383 static struct pernet_operations caif_net_ops = {
 384         .init = caif_init_net,
 385         .exit = caif_exit_net,
 386         .id   = &caif_net_id,
 387         .size = sizeof(struct caif_net),
 388 };
 389
 390 /* Initialize Caif devices list */
 391 static int __init caif_device_init(void)
 392 {
 393         int result;
 394         cfg = cfcnfg_create();
 395         if (!cfg) {
 396                 pr_warn("can't create cfcnfg\n");
 397                 goto err_cfcnfg_create_failed;
 398         }
 399         result = register_pernet_device(&caif_net_ops);
 400
 401         if (result) {
 402                 kfree(cfg);
 403                 cfg = NULL;
 404                 return result;
 405         }
 406         dev_add_pack(&caif_packet_type);
 407         register_netdevice_notifier(&caif_device_notifier);
 408
 409         return result;
 410 err_cfcnfg_create_failed:
 411         return -ENODEV;
 412 }
 413
 414 static void __exit caif_device_exit(void)
 415 {
 416         dev_remove_pack(&caif_packet_type);
 417         unregister_pernet_device(&caif_net_ops);
 418         unregister_netdevice_notifier(&caif_device_notifier);
 419         cfcnfg_remove(cfg);
 420 }
 421
 422 module_init(caif_device_init);
 423 module_exit(caif_device_exit);