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