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/kernel.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/net.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/mutex.h>
  19 #include <net/netns/generic.h>
  20 #include <net/net_namespace.h>
  21 #include <net/pkt_sched.h>
  22 #include <net/caif/caif_device.h>
  23 #include <net/caif/caif_layer.h>
  24 #include <net/caif/cfpkt.h>
  25 #include <net/caif/cfcnfg.h>
  26
  27 MODULE_LICENSE("GPL");
  28
  29 /* Used for local tracking of the CAIF net devices */
  30 struct caif_device_entry {
  31         struct cflayer layer;
  32         struct list_head list;
  33         struct net_device *netdev;
  34         int __percpu *pcpu_refcnt;
  35 };
  36
  37 struct caif_device_entry_list {
  38         struct list_head list;
  39         /* Protects simulanous deletes in list */
  40         struct mutex lock;
  41 };
  42
  43 struct caif_net {
  44         struct cfcnfg *cfg;
  45         struct caif_device_entry_list caifdevs;
  46 };
  47
  48 static int caif_net_id;
  49
  50 struct cfcnfg *get_cfcnfg(struct net *net)
  51 {
  52         struct caif_net *caifn;
  53         BUG_ON(!net);
  54         caifn = net_generic(net, caif_net_id);
  55         BUG_ON(!caifn);
  56         return caifn->cfg;
  57 }
  58 EXPORT_SYMBOL(get_cfcnfg);
  59
  60 static struct caif_device_entry_list *caif_device_list(struct net *net)
  61 {
  62         struct caif_net *caifn;
  63         BUG_ON(!net);
  64         caifn = net_generic(net, caif_net_id);
  65         BUG_ON(!caifn);
  66         return &caifn->caifdevs;
  67 }
  68
  69 static void caifd_put(struct caif_device_entry *e)
  70 {
  71         irqsafe_cpu_dec(*e->pcpu_refcnt);
  72 }
  73
  74 static void caifd_hold(struct caif_device_entry *e)
  75 {
  76         irqsafe_cpu_inc(*e->pcpu_refcnt);
  77 }
  78
  79 static int caifd_refcnt_read(struct caif_device_entry *e)
  80 {
  81         int i, refcnt = 0;
  82         for_each_possible_cpu(i)
  83                 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
  84         return refcnt;
  85 }
  86
  87 /* Allocate new CAIF device. */
  88 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
  89 {
  90         struct caif_device_entry_list *caifdevs;
  91         struct caif_device_entry *caifd;
  92
  93         caifdevs = caif_device_list(dev_net(dev));
  94         BUG_ON(!caifdevs);
  95
  96         caifd = kzalloc(sizeof(*caifd), GFP_ATOMIC);
  97         if (!caifd)
  98                 return NULL;
  99         caifd->pcpu_refcnt = alloc_percpu(int);
 100         caifd->netdev = dev;
 101         dev_hold(dev);
 102         return caifd;
 103 }
 104
 105 static struct caif_device_entry *caif_get(struct net_device *dev)
 106 {
 107         struct caif_device_entry_list *caifdevs =
 108             caif_device_list(dev_net(dev));
 109         struct caif_device_entry *caifd;
 110         BUG_ON(!caifdevs);
 111         list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
 112                 if (caifd->netdev == dev)
 113                         return caifd;
 114         }
 115         return NULL;
 116 }
 117
 118 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 119 {
 120         int err;
 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         err = dev_queue_xmit(skb);
 129         if (err > 0)
 130                 err = -EIO;
 131
 132         return err;
 133 }
 134
 135 /*
 136  * Stuff received packets into the CAIF stack.
 137  * On error, returns non-zero and releases the skb.
 138  */
 139 static int receive(struct sk_buff *skb, struct net_device *dev,
 140                    struct packet_type *pkttype, struct net_device *orig_dev)
 141 {
 142         struct cfpkt *pkt;
 143         struct caif_device_entry *caifd;
 144         int err;
 145
 146         pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
 147
 148         rcu_read_lock();
 149         caifd = caif_get(dev);
 150
 151         if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
 152                         !netif_oper_up(caifd->netdev)) {
 153                 rcu_read_unlock();
 154                 kfree_skb(skb);
 155                 return NET_RX_DROP;
 156         }
 157
 158         /* Hold reference to netdevice while using CAIF stack */
 159         caifd_hold(caifd);
 160         rcu_read_unlock();
 161
 162         err = caifd->layer.up->receive(caifd->layer.up, pkt);
 163
 164         /* For -EILSEQ the packet is not freed so so it now */
 165         if (err == -EILSEQ)
 166                 cfpkt_destroy(pkt);
 167
 168         /* Release reference to stack upwards */
 169         caifd_put(caifd);
 170         return 0;
 171 }
 172
 173 static struct packet_type caif_packet_type __read_mostly = {
 174         .type = cpu_to_be16(ETH_P_CAIF),
 175         .func = receive,
 176 };
 177
 178 static void dev_flowctrl(struct net_device *dev, int on)
 179 {
 180         struct caif_device_entry *caifd;
 181
 182         rcu_read_lock();
 183
 184         caifd = caif_get(dev);
 185         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
 186                 rcu_read_unlock();
 187                 return;
 188         }
 189
 190         caifd_hold(caifd);
 191         rcu_read_unlock();
 192
 193         caifd->layer.up->ctrlcmd(caifd->layer.up,
 194                                  on ?
 195                                  _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
 196                                  _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
 197                                  caifd->layer.id);
 198         caifd_put(caifd);
 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         enum cfcnfg_phy_type phy_type;
 210         struct cfcnfg *cfg;
 211         struct caif_device_entry_list *caifdevs =
 212             caif_device_list(dev_net(dev));
 213
 214         if (dev->type != ARPHRD_CAIF)
 215                 return 0;
 216
 217         cfg = get_cfcnfg(dev_net(dev));
 218         if (cfg == NULL)
 219                 return 0;
 220
 221         switch (what) {
 222         case NETDEV_REGISTER:
 223                 caifd = caif_device_alloc(dev);
 224                 if (!caifd)
 225                         return 0;
 226
 227                 caifdev = netdev_priv(dev);
 228                 caifdev->flowctrl = dev_flowctrl;
 229
 230                 caifd->layer.transmit = transmit;
 231
 232                 if (caifdev->use_frag)
 233                         phy_type = CFPHYTYPE_FRAG;
 234                 else
 235                         phy_type = CFPHYTYPE_CAIF;
 236
 237                 switch (caifdev->link_select) {
 238                 case CAIF_LINK_HIGH_BANDW:
 239                         pref = CFPHYPREF_HIGH_BW;
 240                         break;
 241                 case CAIF_LINK_LOW_LATENCY:
 242                         pref = CFPHYPREF_LOW_LAT;
 243                         break;
 244                 default:
 245                         pref = CFPHYPREF_HIGH_BW;
 246                         break;
 247                 }
 248                 strncpy(caifd->layer.name, dev->name,
 249                         sizeof(caifd->layer.name) - 1);
 250                 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
 251
 252                 mutex_lock(&caifdevs->lock);
 253                 list_add_rcu(&caifd->list, &caifdevs->list);
 254
 255                 cfcnfg_add_phy_layer(cfg,
 256                                      phy_type,
 257                                      dev,
 258                                      &caifd->layer,
 259                                      pref,
 260                                      caifdev->use_fcs,
 261                                      caifdev->use_stx);
 262                 mutex_unlock(&caifdevs->lock);
 263                 break;
 264
 265         case NETDEV_UP:
 266                 rcu_read_lock();
 267
 268                 caifd = caif_get(dev);
 269                 if (caifd == NULL) {
 270                         rcu_read_unlock();
 271                         break;
 272                 }
 273
 274                 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
 275                 rcu_read_unlock();
 276
 277                 break;
 278
 279         case NETDEV_DOWN:
 280                 rcu_read_lock();
 281
 282                 caifd = caif_get(dev);
 283                 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
 284                         rcu_read_unlock();
 285                         return -EINVAL;
 286                 }
 287
 288                 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
 289                 caifd_hold(caifd);
 290                 rcu_read_unlock();
 291
 292                 caifd->layer.up->ctrlcmd(caifd->layer.up,
 293                                          _CAIF_CTRLCMD_PHYIF_DOWN_IND,
 294                                          caifd->layer.id);
 295                 caifd_put(caifd);
 296                 break;
 297
 298         case NETDEV_UNREGISTER:
 299                 mutex_lock(&caifdevs->lock);
 300
 301                 caifd = caif_get(dev);
 302                 if (caifd == NULL) {
 303                         mutex_unlock(&caifdevs->lock);
 304                         break;
 305                 }
 306                 list_del_rcu(&caifd->list);
 307
 308                 /*
 309                  * NETDEV_UNREGISTER is called repeatedly until all reference
 310                  * counts for the net-device are released. If references to
 311                  * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
 312                  * the next call to NETDEV_UNREGISTER.
 313                  *
 314                  * If any packets are in flight down the CAIF Stack,
 315                  * cfcnfg_del_phy_layer will return nonzero.
 316                  * If no packets are in flight, the CAIF Stack associated
 317                  * with the net-device un-registering is freed.
 318                  */
 319
 320                 if (caifd_refcnt_read(caifd) != 0 ||
 321                         cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
 322
 323                         pr_info("Wait for device inuse\n");
 324                         /* Enrole device if CAIF Stack is still in use */
 325                         list_add_rcu(&caifd->list, &caifdevs->list);
 326                         mutex_unlock(&caifdevs->lock);
 327                         break;
 328                 }
 329
 330                 synchronize_rcu();
 331                 dev_put(caifd->netdev);
 332                 free_percpu(caifd->pcpu_refcnt);
 333                 kfree(caifd);
 334
 335                 mutex_unlock(&caifdevs->lock);
 336                 break;
 337         }
 338         return 0;
 339 }
 340
 341 static struct notifier_block caif_device_notifier = {
 342         .notifier_call = caif_device_notify,
 343         .priority = 0,
 344 };
 345
 346 /* Per-namespace Caif devices handling */
 347 static int caif_init_net(struct net *net)
 348 {
 349         struct caif_net *caifn = net_generic(net, caif_net_id);
 350         BUG_ON(!caifn);
 351         INIT_LIST_HEAD(&caifn->caifdevs.list);
 352         mutex_init(&caifn->caifdevs.lock);
 353
 354         caifn->cfg = cfcnfg_create();
 355         if (!caifn->cfg) {
 356                 pr_warn("can't create cfcnfg\n");
 357                 return -ENOMEM;
 358         }
 359
 360         return 0;
 361 }
 362
 363 static void caif_exit_net(struct net *net)
 364 {
 365         struct caif_device_entry *caifd, *tmp;
 366         struct caif_device_entry_list *caifdevs =
 367             caif_device_list(net);
 368         struct cfcnfg *cfg;
 369
 370         rtnl_lock();
 371         mutex_lock(&caifdevs->lock);
 372
 373         cfg = get_cfcnfg(net);
 374         if (cfg == NULL) {
 375                 mutex_unlock(&caifdevs->lock);
 376                 return;
 377         }
 378
 379         list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
 380                 int i = 0;
 381                 list_del_rcu(&caifd->list);
 382                 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
 383
 384                 while (i < 10 &&
 385                         (caifd_refcnt_read(caifd) != 0 ||
 386                         cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
 387
 388                         pr_info("Wait for device inuse\n");
 389                         msleep(250);
 390                         i++;
 391                 }
 392                 synchronize_rcu();
 393                 dev_put(caifd->netdev);
 394                 free_percpu(caifd->pcpu_refcnt);
 395                 kfree(caifd);
 396         }
 397         cfcnfg_remove(cfg);
 398
 399         mutex_unlock(&caifdevs->lock);
 400         rtnl_unlock();
 401 }
 402
 403 static struct pernet_operations caif_net_ops = {
 404         .init = caif_init_net,
 405         .exit = caif_exit_net,
 406         .id   = &caif_net_id,
 407         .size = sizeof(struct caif_net),
 408 };
 409
 410 /* Initialize Caif devices list */
 411 static int __init caif_device_init(void)
 412 {
 413         int result;
 414
 415         result = register_pernet_device(&caif_net_ops);
 416
 417         if (result)
 418                 return result;
 419
 420         register_netdevice_notifier(&caif_device_notifier);
 421         dev_add_pack(&caif_packet_type);
 422
 423         return result;
 424 }
 425
 426 static void __exit caif_device_exit(void)
 427 {
 428         unregister_pernet_device(&caif_net_ops);
 429         unregister_netdevice_notifier(&caif_device_notifier);
 430         dev_remove_pack(&caif_packet_type);
 431 }
 432
 433 module_init(caif_device_init);
 434 module_exit(caif_device_exit);