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